WorldWideScience

Sample records for cell wall ultrastructure

  1. Ultrastructure of organic cell walls in Proterozoic microalgae

    Science.gov (United States)

    Moczydlowska-Vidal, M.

    2009-04-01

    The antiquity of life has been well appreciated since the discoveries of microfossils and confirmation of their authenticity, as well as the recognition of geochemical signs of biogenicity in the Archean successions. Resolving the biological affinities of early biota is essential for the unravelling the changes that led to modern biodiversity, but also for the detection of possible biogenic records outside of the terrestrial biosphere. Advanced techniques in microscopy, tomography and spectroscopy applied to examine individual microfossils at the highest attainable spatial resolution have provided unprecedented insights into micro- and nano-scale structure and composition of organic matter. Transmission and scanning electron microscopy studies of the wall ultrastructure of sphaeromorphic and ornamented acritarchs have revealed complex, single to multilayered walls, having a unique texture in sub-layers and an occasionally preserved trilaminar sheath structure (TLS) of the cell wall. A variety of optical characteristics, the electron density and texture of fabrics of discrete layers, and the properties of biopolymers may indicate the polyphyletic affiliations of such microfossils and/or the preservation of various stages (vegetative, resting) in their life cycle. I evaluate the morphological features of organic-walled unicellular microfossils in conjunction with their cell wall ultrastructure to infer their life cycle and to recognize various developmental stages represented among microfossils attributed to a single form-taxon. Several cases of fine wall ultrastructure in microfossils have been documented and have had a conclusive influence on understanding their affinities. Some Proterozoic and Cambrian leiosphaerids are of algal affinities. Certain specimens represent chlorophyceaens, having the multilayered composite wall with TLS structure known from vegetative and resting cells in modern genera of the Chlorococcales and Volvocales. The wall ultrastructure of

  2. Ultrastructure and biochemistry of the cell wall of Methanococcus voltae.

    OpenAIRE

    Koval, S F; Jarrell, K F

    1987-01-01

    The ultrastructure and chemical composition of the cell wall of the marine archaebacterium Methanococcus voltae were studied by negative-staining and freeze-etch electron microscopy and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. M. voltae possesses a single regularly structured (RS) protein layer external to the plasma membrane. Freeze-etch preparations of cells indicated that the protein subunits are hexagonally arranged with a center-to-center spacing of approximately 10 ...

  3. Characters of Fractal Ultrastructure in Wood Cell Wall

    Institute of Scientific and Technical Information of China (English)

    LI Beimei; ZHAO Guangjie

    2006-01-01

    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.

  4. Ultrastructure of Fibre and Parenchyma Cell Walls During Early Stages of Culm Development in Dendrocalamus asper

    OpenAIRE

    Gritsch, Cristina Sanchis; Murphy, Richard J.

    2005-01-01

    • Background and Aims The anatomy of bamboo culms and the multilayered structure of fibre cell walls are known to be the main determinant factors for its physical and mechanical properties. Studies on the bamboo cell wall have focussed mainly on fully elongated and mature fibres. The main aim of this study was to describe the ultrastructure of primary and secondary cell walls in culm tissues of Dendrocalamus asper at different stages of development.

  5. Ultrastructural changes of cell walls under intense mechanical treatment of selective plant raw material

    International Nuclear Information System (INIS)

    Structural changes of cell walls under intense mechanical treatment of corn straw and oil-palm fibers were studied by electron and light microscopy. Differences in the character of destruction of plant biomass were revealed, and the dependence of destruction mechanisms on the structure of cell walls and lignin content was demonstrated. We suggest that the high reactivity of the particles of corn straw (about 18% of lignin) after intense mechanical treatment is related to disordering of cell walls and an increase of the surface area, while in the case of oil palm (10% of lignin) the major contribution into an increase in the reactivity is made by an increase of surface area. -- Highlights: ► Structure of cell walls determines the processes of plant materials' destruction. ► Ultrastructure of highly lignified materials strongly disordering by mechanical action. ► Ultrastructure of low-lignified materials is not disordering by mechanical action.

  6. Abiotic and enzymatic degradation of wheat straw cell wall: a biochemical and ultrastructural investigation.

    Science.gov (United States)

    Lequart, C; Ruel, K; Lapierre, C; Pollet, B; Kurek, B

    2000-07-14

    The action of an abiotic lignin oxidant and a diffusible xylanase on wheat straw was studied and characterized at the levels of the molecular structures by chemical analysis and of the cell wall ultrastructure by transmission electron microscopy. While distinct chemical changes in the target polymers were observed when each system was used separately, a combination of the two types of catalysts did not significantly increase either lignin oxidation or hemicellulose hydrolysis. Microscopic observations however revealed that the supramolecular organization of the cell wall polymers was significantly altered. This suggests that the abiotic Mn-oxalate complex and the xylanase cooperate in modifying the cell wall architecture, without noticeably enhancing the degradation of the constitutive polymers. PMID:10949315

  7. Cell wall ultrastructures of the Proterozoic acritarch Leiosphaeridia asperata and their implications for biological affinity

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Abundant sphaeroidal acritarch Leiosphaeridia asperata,with vesicle size ranging from 13 to 360 μm,occurred in the Proterozoic Liulaobei Formation shales in Huainan,Anhui Province.TEM/SEM studies of these sphaeroidal acritarchs have revealed complex ultrastructures,including ridges,bands,and possible trilaminar structures(TLS).Ridges,spaced ~1 μm apart,are distributed regularly on the vesicle internal surface of one specimen.Some specimens have alternating electron-dense and electron-tenuous bands that are perpendicular to vesicle walls.Some specimens have trilaminar structures(TLS),while a few others have both bands and TLS.These wall ultrastructures provide evidence that the Liulaobei leiosphaerids are of green microalgae.The variation in wall ultrastructures may represent various stages in a life cycle or developmental phases in the cyst formation analogous to some modern chlorophyceaen microalgae.

  8. Sucrose synthase affects carbon partitioning to increase cellulose production and altered cell wall ultrastructure

    OpenAIRE

    Coleman, Heather D.; Yan, Jimmy; Mansfield, Shawn D

    2009-01-01

    Overexpression of the Gossypium hirsutum sucrose synthase (SuSy) gene under the control of 2 promoters was examined in hybrid poplar (Populus alba × grandidentata). Analysis of RNA transcript abundance, enzyme activity, cell wall composition, and soluble carbohydrates revealed significant changes in the transgenic lines. All lines showed significantly increased SuSy enzyme activity in developing xylem. This activity manifested in altered secondary cell wall cellulose content per dry weight in...

  9. Ultrastructural and Chemical Evidence That the Cell Wall of Green Cotton Fiber Is Suberized 1

    Science.gov (United States)

    Yatsu, L. Y.; Espelie, Karl E.; Kolattukudy, P. E.

    1983-01-01

    Green cotton (Gossypium hirsutum L.) fibers were shown by electron microscopy to have numerous thin concentric rings around the lumen of the cell. These rings possessed a lamellar fine structure characteristic of suberin. LiA1D4 depolymerization and gas chromatography-mass spectrometry analysis showed the presence of a suberin polymer in the green cotton with the major aliphatic monomers being ω-hydroxydocosanoic acid (70%) and docosanedoic acid (25%). Ordinary white cotton was shown by chemical and ultrastructural examination to be encircled by a thin cuticular polymer containing less than 0.5% of the aliphatic components found in green cotton. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:16663251

  10. Ultrastructural effects of lysozymes on the cell wall of Caryophanon latum.

    Science.gov (United States)

    Trentini, W C; Murray, R G

    1975-02-01

    When Caryophanon latum was exposed to egg white lysozyme in isotonic sucrose and observed by phase-contrast microscopy, protoplasts emerged along the length of the trichomes, apparently at sites corresponding to cross septa. Electron microscopy of sections revealed that this enzyme initially attacked the core of the septal peptidoglycan and delamination of septa resulted. The inner densely staining layer of the lateral and polar wall (considered to contain peptidoglycan as the major component) remained intact except for destruction at the advancing tip of partial septa; protoplasts or cell debris could escape from the gaps formed at developing septa. Treatment of intact trichomes with pronase, a lipase - phospholipase C mixture, EDTA, glutaraldehyde, or heat, before exposure to egg white lysozyme did not alter this pattern nor did it render the remaining peptidoglycan more susceptible to attack. The wall material external to the peptidoglycan was solubilized by pronase. The peptidoglycan remaining after lysozyme treatment was not morphologically changed by treatment with pronase. Lysozyme derived from Chalaropsis hydrolyzed incomplete septa initially, while the lateral and polar wall and complete septa were degraded later. Therefore, it is most probable that the inner dense layer does contain the peptidoglycan component and that some biochemical maturation distinguishes the substrate for these enzymes in the lateral wall and septa. PMID:803400

  11. Cell Wall

    OpenAIRE

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

    2008-01-01

    This chapter covers our present knowledge of cell wall proteomics highlighting the distinctive features of cell walls and cell wall proteins in relation to problems encountered for protein extraction, separation and identification. It provides clues to design strategies for efficient cell wall proteomic studies. It gives an overview of the kinds of proteins that have yet been identified: the expected proteins vs the identified proteins. Finally, the new vision of the cell wall proteome, and t...

  12. Structural and ultrastructural evaluation of the aortic wall after transplantation of bone marrow-derived cells (BMCs) in a model for atherosclerosis.

    Science.gov (United States)

    Felix, Alyne Souza; Monteiro, Nemesis; Rocha, Vinícius Novaes; Oliveira, Genilza; Nascimento, Ana Lucia; de Carvalho, Laís; Thole, Alessandra; Carvalho, Jorge

    2015-08-01

    Stem cells are characterized by their ability to differentiate into multiple cell lineages and display the paracrine effect. The aim of this work was to evaluate the effect of therapy with bone marrow-derived cells (BMCs) on glucose, lipid metabolism, and aortic wall remodeling in mice through the administration of a high-fat diet and subsequent BMCs transplantation. C57BL/6 mice were fed a control diet (CO group) or an atherogenic diet (AT group). After 16 weeks, the AT group was divided into 4 subgroups: an AT 14 days group and AT 21 days group that were given an injection of vehicle and sacrificed after 14 and 21 days, respectively, and an AT-BMC 14 days group and AT-BMC 21 days group that were given an injection of BMCs and sacrificed after 14 and 21 days, respectively. The BMCs transplant had reduced blood glucose, triglycerides, and total cholesterol. There was no significant difference in relation to body mass between the transplanted groups and non-transplanted groups, and all were different than CO. There was no significant difference in the glycemic curve among AT 14 days, AT-BMC 14 days, and AT 21 days, and these were different than the CO and the AT-BMC 21 days groups. The increased thickness of the aortic wall was observed in all atherogenic groups, but was significantly smaller in group AT-BMC 21 days compared to AT 14 days and AT 21 days. Vacuoles in the media tunic, delamination and the thinning of the elastic lamellae were observed in AT 14 days and AT 21 days. The smallest number of these was displayed on the AT-BMC 14 days and AT-BMC 21 days. Marking to CD105, CD133, and CD68 were observed in AT 14 days and AT 21 days. These markings were not observed in AT-BMC 14 days or in AT-BMC 21 days. Electron micrographs show the beneficial remodeling in AT-BMC 14 days and AT-BMC 21 days, and the structural organization was similar to the CO group. Vesicles of pinocytosis, projection of smooth muscle cells, and delamination of the internal elastic lamina

  13. Ultrastructural characteristics of the vascular wall components of ruptured atherosclerotic abdominal aortic aneurysm

    Directory of Open Access Journals (Sweden)

    Tanasković Irena

    2013-01-01

    Full Text Available The aim of this study was to determine the ultrastructural characteristics of cell populations and extracellular matrix components in the wall of ruptured atherosclerotic abdominal aortic aneurysm (AAA. We analyzed 20 samples of ruptured AAA. For orientation to the light microscopy, we used routine histochemical techniques by standard procedures. For ultrastructural analysis, we applied transmission electron microscopy (TEM. Our results have shown that ruptured AAA is characterized by the remains of an advanced atherosclerotic lesion in the intima followed by a complete absence of endothelial cells, the disruption of basal membrane and disruption of internal elastic lamina. On plaque margins as well as in the inner media we observed smooth muscle cells (SMCs that posses a euchromatic nucleus, a well-developed granulated endoplasmic reticulum around the nucleus and reduced myofilaments. The remains of the ruptured lipid core were acellular in all samples; however, on the lateral sides of ruptured plaque we observed a presence of two types of foam cells (FCs, spindle- and star-shaped. Fusiform FCs possess a well-differentiated basal lamina, caveolae and electron dense bodies, followed by a small number of lipid droplets in the cytoplasm. Star-shaped FCs contain a large number of lipid droplets and do not possess basal lamina. On the inner margins of the plaque, we observed a large number of cells undergoing apoptosis and necrosis, extracellular lipid droplets as well as a large number of lymphocytes. The media was thinned out with disorganized elastic lamellas, while the adventitia exhibited leukocyte infiltration. The presented results suggest that atherosclerotic plaque in ruptured AAA contains vascular SMC synthetic phenotype and two different types of FCs: some were derived from monocyte/macrophage lineage, while others were derived from SMCs of synthetic phenotype. The striking plaque hypocellularity was the result of apoptosis and necrosis

  14. Long clinostation influence on the ultrastructure of Funaria hygrometrica moss protonema cells

    Science.gov (United States)

    Nedukha, E. M.

    Changes in the ultrastructure of protonema cells of Funaria hygrometrica, cultivated during 20 days on a horizontal clinostat (2 rev/min), were determined by the electron microscopy method. About 20% of the cells were almost identical to those in the control, 20% were destructive cells, and in 60% ultrastructure changes were observed. The heterogeneity of the reaction demonstrated the evidence of sensitive cells on the clinostation process. Changes affected the ultrastructure of plastids, wall of the cell, and the form of the nucleus as well. Starch disappeared from chloroplasts practically completely, thylakoids swelled, granas frequently disappeared from plastids. Peroxisomes number in cells increased appreciably, width of cell walls decreased by almost half their size. Ca++-binding sites were revealed in cytoplasma of cells. Electronocytochemical exposure of ATPases activity with the presence of Mg++ and Ca++ ions showed that Mg2+-ATPase activity localization in clinosted cells was not too different from the control, while Ca2+-ATPase location presented differences in plasmalemma and Ca-sites. These changes are perhaps connected with the membranes permeability breaking and affect the plant cells adaptation to the influence of hypogravitation.

  15. Ultrastructural effects of heat shock and ionizing radiation on leaf cells of winter wheat

    International Nuclear Information System (INIS)

    Full text: The effects of heat shock (HS) and gamma-radiation (GR) on mesophyll ultrastructure of the first leaf of etiolated 5-day winter wheat seedlings (Triticum aestivum L.) were studied. Two hours after the HS considerable changes in cell ultrastructure were noted. Nuclei were lociniate-shaped as a result of invagination of nuclear membranes, with condensed chromatin. Some nuclei with particularly damaged membranes were present. Etioplasts took rounded shape and were situated next to cell walls in close contact with each other. The distance between the inner membranes, as well as a number of the electron-light vesicles were increased, with electron-dense plastoglobules and large starch grains clearly visible. The majority of mitochondria were smaller than in the control cells, had well-defined cristae and were in contact with plastids and nuclei. Rough endoplasmic reticulum was well developed, which could indicate protein synthesis taking place. Considerable increase in cell wall density was noted. GR (dose 100 Gy, 4 hours following irradiation) caused less considerable changes of cell ultrastructure. Nuclei took lociniate-shape, nuclear chromatin had small-grained structure. Some etioplasts changed their shape. Plastoglobules, as well as large starch grains in the stroma of most etioplasts, were well visible. Mitochondria were in close contact with etioplasts, nuclei, and with each other. Endoplasmic reticulum was well developed but with ribosomes covering the membrane surface less densely compared to cells exposed to HS. The obtained data allowed to conclude that ultrastructure of all studied organelles was changing during 2 h after heat shock. These changes could be either the result of cell damage or adaptation mechanisms. In contrast, a relatively short time interval (4 hours) after exposure to gamma-radiation (dose 100 Gy), was shown to be insufficient for the development of cellular ultrastructural changes

  16. THE ULTRASTRUCTURE OF SEPARATED AND CULTURED CELL OF PORPHYRA YEZOENSIS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There are many reports that cells (protoplasts) separated from the thallus of Porphyra by enzyme can develop to normal leafy thalli in the same way as monospores. But there are few investigations on the subcellular structure of the isolated vegetative cell for comparison with the subcellular structure of monospores. To clarify whether the separated and cultured cells undergo the same or similar ultrastructure changes during culture and germination as monospores undergo in their formation and germination, we observed their ultrastructure, compared them with those of the monospore and found that the ultrastructure of separated and cultured cells did not have the characteristic feature as that of monospore formation, such as production of small and large fibrous vesicles, but was accompanied by vacuolation and starch mobilization like that in monospore germination. The paper also discusses the relations between monospores and separated and cultured cells.

  17. Ultrastructure study of apple meristem cells during cryopreservation

    Science.gov (United States)

    The ultrastructure of apple (Malus x domestica Borkh.) meristem cells was studied before and after cold acclimation (CA) and during the steps of PVS2 vitrification. We compared cells of in vitro grown shoots of two cultivars, Grushovka Vernenskaya and Voskhod. Cells of the two cultivars were simila...

  18. Changes in cell ultrastructure and morphology of Arabidopsis thaliana roots after coumarins treatment

    Directory of Open Access Journals (Sweden)

    Ewa Kupidłowska

    2014-02-01

    Full Text Available The ultrastructure and morphology of roots treated with coumarin and umbelliferone as well as the reversibility of the coumarins effects caused by exogenous GA, were studied in Arabidopsis thaliana. Both coumarins suppressed root elongation and appreciably stimulated radial expansion of epidermal and cortical cells in the upper part of the meristem and in the elongation zone. The gibberellic acid applied simultaneously with coumarins decreased their inhibitory effect on root elongation and reduced cells swelling.Microscopic observation showed intensive vacuolization of cells and abnormalities in the structure of the Golgi stacks and the nuclear envelope. The detection of active acid phosphatase in the cytosol of swollen cells indicated increased membrane permeability. Significant abnormalities of newly formed cell walls, e.g. the discontinuity of cellulose layer, uncorrect position of walls and the lack of their bonds with the mother cell wall suggest that coumarins affected the cytoskeleton.

  19. Effects of Photodynamic Therapy on the Ultrastructure of Glioma Cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To study the change in ultrastructure of C6 glioma cells after photodynamic therapy (PDT), to compare morphological differences in necrosis and apoptosis before and after PDT treatment, and to evaluate the effect of photodynamic therapy on the blood brain tumor barrier (BTB) of C6 glioma. Methods The model was produced by transplanting C6 glioma cells cultured in vitro using Peterson method into the caudate nuclei of Wister rats. The experiment group received PDT for two weeks after the operation. The sub-cellular structure, blood-brain-barrier (BBB) and BTB in both groups were observed under electron microscope. Results Apoptosis in different phases and necrosis could be observed in some C6 glioma cells.Swelling occurred on the ultrastructure of cellular organs such as mitochondria and endoplasmic reticulum in most of the cells.Damage to the BTB, reduction of the number of cellular organs in endothelial cells of the capillary blood vessels, stretch of the tight junction, and enlargement of the gaps between endothelial cells were also seen in the experiment group. Meanwhile,limited impact on the normal sub-cellular structures and BBB was observed. Conclusion PDT could induce apoptosis and necrosis of C6 glioma cells due to the damage to the ultrastructure of mitochondria and endoplasmic reticulum. The weakened function of C6 glioma BTB initiated by PDT makes it possible to perform a combined therapy of PDT and chemotherapy for glioma.

  20. Cutaneous postirradiation sarcoma. Ultrastructural evidence of pluripotential mesenchymal cell derivation

    International Nuclear Information System (INIS)

    A 75-year-old man developed synchronous multicentric cutaneous sarcomas and basal cell carcinoma of the face 57 years after receiving irradiation for acne. During the previous 30 years he had been treated many times for actinic keratoses and basal cell carcinomas. Surgical treatment had included total nasectomy, excision, and replacement of the skin of the upper and lower lips and the chin. Due to the multiplicity of morphologic patterns, it was difficult to subtype the sarcomas. Ultrastructural studies showed histiocyte-like, fibroblast-like and vasoformative cells suggesting an origin from a pluripotential mesenchymal stem cells

  1. 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

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  3. 蓝猪耳花粉管细胞壁超微结构的FESEM和AFM比较研究%Ultrastructure of Pollen Tube Cell Wall in Torenia fournieri L.Observed by FESEM and AFM

    Institute of Scientific and Technical Information of China (English)

    吴娟子

    2011-01-01

    [目的]比较场发射扫描电镜(FESEM)和原子力显微镜(AFM)观察蓝猪耳花粉管表面形貌和细胞壁中纤维素微纤丝排列的效果.[方法]蓝猪耳花粉离体培养2h后,利用FESEM和AFM原位观察无损的花粉管表面形貌和细胞壁的精细结构.[结果]FESEM可见花粉管表面粗糙的网状结构;AFM可获得花粉管的三维立体图像,并可见花粉管细胞壁物质的精细结构和纤维素微纤丝的排列情况.[结论]AFM是一种观察花粉管表面结构和细胞壁中纤维素微纤丝排向的有效手段.%[Objective] To compare the effects of FESEM and AFM observing the surface topography and cellulose microfibrils arrangement of pollen tube cell wall in Torenia foumieri L.. [ Method] After 2 h culture,the surface topography and cellulose microfibrils arrangement of pollen tubes were observed by FESEM and AFM. [ Result ] FESEM image revealed the rough network structure of pollen tube, AFM revealed the three-dimensional images of pollen tubes and the fine structure of cell wall and the cellulose microfilaments orientation. [ Conclusion ] AFM was a powerful technique for examining the surface topography and cellulose microfibrils arrangement of pollen tube wall.

  4. Linking progression of fibrotic lung remodeling and ultrastructural alterations of alveolar epithelial type II cells in the amiodarone mouse model.

    Science.gov (United States)

    Birkelbach, Bastian; Lutz, Dennis; Ruppert, Clemens; Henneke, Ingrid; Lopez-Rodriguez, Elena; Günther, Andreas; Ochs, Matthias; Mahavadi, Poornima; Knudsen, Lars

    2015-07-01

    Chronic injury of alveolar epithelial type II cells (AE2 cells) represents a key event in the development of lung fibrosis in animal models and in humans, such as idiopathic pulmonary fibrosis (IPF). Intratracheal delivery of amiodarone to mice results in a profound injury and macroautophagy-dependent apoptosis of AE2 cells. Increased autophagy manifested in AE2 cells by disturbances of the intracellular surfactant. Hence, we hypothesized that ultrastructural alterations of the intracellular surfactant pool are signs of epithelial stress correlating with the severity of fibrotic remodeling. With the use of design-based stereology, the amiodarone model of pulmonary fibrosis in mice was characterized at the light and ultrastructural level during progression. Mean volume of AE2 cells, volume of lamellar bodies per AE2 cell, and mean size of lamellar bodies were correlated to structural parameters reflecting severity of fibrosis like collagen content. Within 2 wk amiodarone leads to an increase in septal wall thickness and a decrease in alveolar numbers due to irreversible alveolar collapse associated with alveolar surfactant dysfunction. Progressive hypertrophy of AE2 cells and increase in mean individual size and total volume of lamellar bodies per AE2 cell were observed. A high positive correlation of these AE2 cell-related ultrastructural changes and the deposition of collagen fibrils within septal walls were established. Qualitatively, similar alterations could be found in IPF samples with mild to moderate fibrosis. We conclude that ultrastructural alterations of AE2 cells including the surfactant system are tightly correlated with the progression of fibrotic remodeling. PMID:25957292

  5. Cell wall proteomics of crops

    OpenAIRE

    Komatsu, Setsuko; Yanagawa, Yuki

    2013-01-01

    Cell wall proteins play key roles in cell structure and metabolism, cell enlargement, signal transduction, responses to environmental stress, and many other physiological events. Agricultural crops are often used for investigating stress tolerance because cultivars with differing degrees of tolerance are available. Abiotic and biotic stress factors markedly influence the geographical distribution and yields of many crop species. Crop cell wall proteomics is of particular importance for improv...

  6. The Chlamydomonas cell wall: characterization of the wall framework

    OpenAIRE

    1985-01-01

    The cell wall of the biflagellate alga Chlamydomonas reinhardtii is a multilayered, extracellular matrix composed of carbohydrates and 20-25 polypeptides. To learn more about the forces responsible for the integrity of this cellulose-deficient cell wall, we have begun studies to identify and characterize the framework of the wall and to determine the effects of the cell wall-degrading enzyme, lysin, on framework structure and protein composition. In these studies we used walls released into t...

  7. Alterations of Intracellular Ca2+ Concentration and Ultrastructure in Spruce Apical Bud Cells during Seasonal Transition

    Institute of Scientific and Technical Information of China (English)

    Jian Lingcheng; Sun Delan; Deng Jiangming; Song Yanmei; Paul H. Li

    2004-01-01

    Potassium antimonite was used to localize Ca2+ in the apical bud cells of spruce from July 1999 to May 2000. During the period of active growth (July 14), Calcium precipitates, an indication of Ca2+ localization, were mainly distributed in vacuoles, intercellular spaces and cell walls. Few Ca2+ deposits localized in the cytosol and nucleus, showing a low level of the cytosolic and nuclear Ca2+ concentration in the warm summer. In August, some Ca2+ deposits appeared in the cytosol and nuclei, indicating that Ca2+ influx occurred in the cytosol and nucleus as the day length became shorter. From September to November, high levels of the cytosolic and nuclear Ca2+ remained. During the mid-winter (December and January), the distribution of Ca2+ deposits and the ultrastructures in the cells were altered dramatically. Plasmolysis occurred in many cells due to the protoplasmic dehydration. In addition plasmalemma invagination and nuclear chromatin aggregation also occurred. A large number of Ca2+ deposits appeared in the space between the plasmalemma and the cell wall. And also some Ca2+ deposits were distributed in the plastids. However, few Ca2+ deposits were observed in the cytosol and nuclei. By spring of the next year (May), when plants were de-acclimated and resumed active growth, Ca2+ subcellular localization essentially restored to that observed in July of the last year, i.e., the cells contained low cytosolic and nuclear Ca2+ concentrations; Ca2+ deposits were mainly distributed in the vacuoles, cell walls and intercellular spaces. The relationships between the seasonal changes of intracellular Ca2+ concentration and the development of dormancy/cold acclimation, as well as plasmolysis associated with dormancy and cold hardiness were discussed.

  8. Ultra-structural identification of interstitial cells of Cajal in the zebrafish Danio rerio

    OpenAIRE

    Ball, Evan R.; Matsuda, Miho M.; Dye, Louis; Hoffmann, Victoria; Zerfas, Patricia M; Szarek, Eva; Rich, Adam; Chitnis, Ajay B.; Stratakis, Constantine A.

    2012-01-01

    The interstitial cells of Cajal (ICCs) are important mediators of gastrointestinal (GI) motility because of their role as pacemakers in the GI tract. In addition to their function, ICCs are also structurally distinct cells most easily identified by their ultra-structural features and expression of the tyrosine kinase receptor c-KIT. ICCs have been described in mammals, rodents, birds, reptiles, and amphibians, but there are no reports at the ultra-structural level of ICCs within the GI tract ...

  9. Radiation induced cell death in cervical squamous cell carcinoma. An immunohistochemical and ultrastructural study

    International Nuclear Information System (INIS)

    To study the process of cell death in cervical squamous cell carcinoma (SCC) after radiation, an ultrastructural and immunohistochemical study was performed. Paraffin-embedded tissue blocks of biopsy samples pre- and post-radiation stage III SCC (n=15) were collected. Irradiation caused varying ultrastructural changes including nuclear and cytoplasmic disorganization suggesting cell necrosis. Immunohistochemically, the pre-radiation specimens showed no positive reaction for tumor necrosis factor-alpha (TNF-α), tumor necrosis factor-receptor (TNF-γ) or Fas. C-fos, p53 and bcl-2 showed positive reactions in only a few non-irradiated specimens. All of the irradiated specimens showed a positive reaction for TNF-α, and variable positive reactions were observed for TNF-γ, Fas, p53, c-fos and bcl-2. These results suggest that TNF-α, TNF-γ, and c-fos are responsible for radiation induced cell death in cervical SCC. (author)

  10. DIVERSITY IN THE DISTRIBUTION OF POLYSACCHARIDE AND GLYCOPROTEIN EPITOPES IN THE CELL WALLS OF BRYOPHYTES: NEW EVIDENCE FOR THE MULTIPLE EVOLUTION OF WATER-CONDUCTING CELLS

    Science.gov (United States)

    Bryophyte water conducting cells produce some of the most unusual wall ultrastructures of any plant. In fact, the only similar sorts of wall structures are produced by herbicidal treatment of higher plants with herbicides that inhibit cellulose biosynthesis. To determine if the similar sorts of st...

  11. The reorganization of root anatomy and ultrastructure of syncytial cells in tomato (Lycopersicon esculentum Mill. infected with potato cyst nematode (Globodera rostochiensis Woll.

    Directory of Open Access Journals (Sweden)

    Sylwia Fudali

    2011-04-01

    Full Text Available The sequence of anatomical and ultrastructural events leading to the syncytium development in tomato roots infected with Globodera rostochiensis was examined. The syncytia were preferentially induced in cortical or pericyclic cells in the elongation zone of root. They developed towards the vascular cylinder by incorporation of new cells via local cell wall breakdown. After surrounding primary phloem bundle and reaching xylem tracheary elements syncytia spread along vascular cylinder. Roots in primary state of growth seemed to be the best place for syncytium induction as syncytia formed in the zone of secondary growth were less hypertrophied. At the ultrastructural level syncytial elements were characterized by strong hypertrophy, breakdown of central vacuole, increased volume of cytoplasm, proliferation of organelles, and enlargement of nuclei. On the syncytial wall adjoining vessels the cell wall ingrowths were formed, while the syncytial walls at interface of phloem were considerably thickened. They lacked of functional plasmodesmata and did not form any ingrowths. Using immunofluorescent-labelling and immunogold-labelling methods tomato expansin 5 protein was localized in nematode infected roots. The distribution of LeEXP A5 was restricted only to the walls of syncytia. The protein distribution pattern indicated that LeEXP A5 could mediates cell wall expansion during hypertrophy of syncytial elements.

  12. Cell Wall Integrity Signaling in Saccharomyces cerevisiae

    OpenAIRE

    Levin, David E.

    2005-01-01

    The yeast cell wall is a highly dynamic structure that is responsible for protecting the cell from rapid changes in external osmotic potential. The wall is also critical for cell expansion during growth and morphogenesis. This review discusses recent advances in understanding the various signal transduction pathways that allow cells to monitor the state of the cell wall and respond to environmental challenges to this structure. The cell wall integrity signaling pathway controlled by the small...

  13. Back wall solar cell

    Science.gov (United States)

    Brandhorst, H. W., Jr. (Inventor)

    1978-01-01

    A solar cell is disclosed which comprises a first semiconductor material of one conductivity type with one face having the same conductivity type but more heavily doped to form a field region arranged to receive the radiant energy to be converted to electrical energy, and a layer of a second semiconductor material, preferably highly doped, of opposite conductivity type on the first semiconductor material adjacent the first semiconductor material at an interface remote from the heavily doped field region. Instead of the opposite conductivity layer, a metallic Schottky diode layer may be used, in which case no additional back contact is needed. A contact such as a gridded contact, previous to the radiant energy may be applied to the heavily doped field region of the more heavily doped, same conductivity material for its contact.

  14. Ultrastructure of Guerin's carcinoma cells after chemotherapy and local tumor irradiation

    International Nuclear Information System (INIS)

    It was established that administration of cisplatin (CP) resulted in pronounced disorders in Guerin's carcinoma cell ultrastructure and did not influence the number of mitoses in the tumor. Main effect of TT was significant reduction of mitotic activity in the tumor against a background of inconsiderable changes in the cell ultrastructure. Administration of CP followed by irradiation changed little in the structural functional state of Guerin's carcinoma cells while Taxotere administration prior to irradiation caused necroses of the tumor tissue and significant reduction of the number of mitoses in the survived cells

  15. Ultrastructure and Development of Anthracoidea Elynae Ustilospores

    Directory of Open Access Journals (Sweden)

    Marcel PARVU

    2009-06-01

    Full Text Available The aim of the study was to examine the ultrastructure of Anthracoidea elynae ustilospores isolated from Kobresia myosuroides (Vill. Fiori plant ovaries, harvested in the Bucegi Mountains, Romania. Samples examination was performed using scanning (SEM and transmission (TEM electron microscopy. The results showed that A. elynae ustilospores had a dynamic ultrastructure, because their three-layered cell wall, nucleus shape, lipid and glycogen accumulations in the cytoplasm changed at each developmental stage. In conclusion, according to the ultrastructural changes, A. elynae ustilospores development may be divided into three stages.

  16. Accelerating forward genetics for cell wall deconstruction

    OpenAIRE

    Vidaurre, Danielle; Bonetta, Dario

    2012-01-01

    The elucidation of the genes involved in cell wall synthesis and assembly remains one of the biggest challenges of cell wall biology. Although traditional genetic approaches, using simple yet elegant screens, have identified components of the cell wall, many unknowns remain. Exhausting the genetic toolbox by performing sensitized screens, adopting chemical genetics or combining these with improved cell wall imaging, hold the promise of new gene discovery and function. With the recent introduc...

  17. Moss cell walls: structure and biosynthesis

    OpenAIRE

    Alison W. Roberts; Eric M Roberts; Haigler, Candace H.

    2012-01-01

    The genome sequence of the moss Physcomitrella patens has stimulated new research examining the cell wall polysaccharides of mosses and the glycosyl transferases that synthesize them as a means to understand fundamental processes of cell wall biosynthesis and plant cell wall evolution. The cell walls of mosses and vascular plants are composed of the same classes of polysaccharides, but with differences in side chain composition and structure. Similarly, the genomes of P. patens and angiosperm...

  18. Ultrastructure of neuronal-like cells differentiated from adult adipose-derived stromal cells

    Institute of Scientific and Technical Information of China (English)

    Changqing Ye; Xiaodong Yuan; Hui Liu; Yanan Cai; Ya Ou

    2010-01-01

    β-mercaptoethanol induces in vitro adult adipose-derived stromal cells (ADSCs) to differentiate into neurons. However, the ultrastructural features of the differentiated neuronal-like cells remain unknown. In the present study, inverted phase contrast microscopy was utilized to observe β-mercaptcethanol-induced differentiation of neuronal-like cells from human ADSCs, and immunocytochemistry and real-time polymerase chain reaction were employed to detect expression of a neural stem cells marker (nestin), a neuronal marker (neuron-specific enolase), and a glial marker (glial fibrillary acidic protein). In addition, ultrastructure of neuronal-like cells was observed by transmission election microscopy. Results revealed highest expression rate of nestin and neuron-specific enolase at 3 and 5 hours following induced differentiation; cells in the 5-hour induction group exhibited a neuronal-specific structure, i.e., Nissl bodies. However, when induction solution was replaced by complete culture medium after 8-hour induction, the differentiated cells reverted to the fibroblast-like morphology from day 1. These results demonstrate that β-mercaptoethanol-induced ADSCs induced differentiation into neural stem cells, followed by morphology of neuronal-like cells. However, this differentiation state was not stable.

  19. Comparative Ultrastructure of Langerhans-Like Cells in Spleens of Ray-Finned Fishes (Actinopterygii)

    Czech Academy of Sciences Publication Activity Database

    Lovy, J.; Wright, G. M.; Speare, D. J.; Tyml, Tomáš; Dyková, Iva

    2010-01-01

    Roč. 271, č. 10 (2010), s. 1229-1239. ISSN 0362-2525 R&D Projects: GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : fish * cyprinidae * halibut * dendritic cells * Langerhans cell * Birbeck granules * ultrastructure Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.773, year: 2010

  20. Freeze-etch studies on the bacterial cell surfaces: action of the cell wall lytic enzymes on the gram-positive cocci

    Directory of Open Access Journals (Sweden)

    Tomochika,Ken-ichi

    1974-12-01

    Full Text Available Using a freeze-etching method, the ultrastructure of cell surface of gram-positive cocci was studied by digesting cell wall with lytic enzyme. In M. lysodeikticus, the cell surface revealed a very simplified ultrastructure, i. e. a single cell wall layer and a single plasma membrane layer. On the contrary, the cell surface of S. aureus exhibited a unique structure composed of two cell wall layers and a single ploasma membrane layer. The wall layers were constituted of 160 -180 A particle layer (CWl which was unsusceptible to the L-ll enzyme and amorphous layer (CW2 which was susceptible. These results suggested that 160-180 A particles in CWl consisted mainly of the teichoic acid.

  1. The cell wall of Fusarium oxysporum

    NARCIS (Netherlands)

    Schoffelmeer, EAM; Klis, FM; Sietsma, JH; Cornelissen, BJC

    1999-01-01

    Sugar analysis of isolated cell walls from three formae speciales of Fusarium oxysporum showed that they contained not only glucose and (N-acetyl)-glucosamine, but also mannose, galactose, and uronic acids, presumably originating from cell wall glycoproteins. Cell wall glycoproteins accounted for 50

  2. Unique aspects of the grass cell wall

    Science.gov (United States)

    Grasses are amongst the most important crops worldwide, and the composition of their cell walls is critical for uses as food, feed, and energy crops. Grass cell walls differ dramatically from dicot cell walls in terms of the major structural polysaccharides present, how those polysaccharides are lin...

  3. Shape dynamics of growing cell walls

    OpenAIRE

    Banerjee, Shiladitya; Scherer, Norbert F.; Dinner, Aaron R.

    2015-01-01

    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...

  4. Tissue organization and cell ultrastructure in the roots of three Arabidopsis species grown at different zinc concentrations

    Directory of Open Access Journals (Sweden)

    M. Čiamporová

    2015-05-01

    Full Text Available The model plant Arabidopsis thaliana is known to be heavy metal-sensitive in contrast to its relative species A. arenosa and A. halleri classified as pseudometallophytes. Quantitative differences in primary root anatomy previously found between A. thaliana and the non-metallicolous (NM and metallicolous (M populations of the non-model Arabidopsis species necessitated further research at cellular and ultrastructural levels. Seedlings of A. thaliana, ecotype Columbia and a natural population Ratkovo, the NM and M populations of A. arenosa and A. halleri were grown on agar medium containing 10 μM (control and 1000 μM Zn2+ for 5 days. Light microscopy confirmed the higher number of cells in the endodermal, cortical and epidermal layers and a higher incidence of additional cell tiers, the so-called middle cortex (MC in the tolerant genotypes. Such differences were present in untreated plants and even more pronounced in plants exposed to excess of zinc (Zn. Electron microscopy of the root tissues at comparable distances from the root tip showed Casparian bands only in the radial cell walls of endodermis of A. halleri M population originating from severely (Cu, Cd and Pb contaminated site. Casparian bands were not differentiated yet in the roots of the other species and populations, and they were not formed in the cell walls between endodermis and MC cells. In the apical cytoplasm of trichoblast bulges, autophagic vacuoles were found only in the sensitive A. thaliana and small vacuoles in the other genotypes. The enhanced concentration of Zn confirmed the higher metal sensitivity of the model species and did not substantially disturb the root cell ultrastructure of the tolerant Arabidopsis species.

  5. Shape dynamics of growing cell walls

    CERN Document Server

    Banerjee, Shiladitya; Dinner, Aaron R

    2015-01-01

    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...

  6. Glycoprotein Hypersecretion Alters the Cell Wall in Trichoderma reesei Strains Expressing the Saccharomyces cerevisiae Dolichylphosphate Mannose Synthase Gene▿

    OpenAIRE

    Perlińska-Lenart, Urszula; Orłowski, Jacek; Laudy, Agnieszka E.; Zdebska, Ewa; Palamarczyk, Grażyna; Kruszewska, Joanna S.

    2006-01-01

    Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increas...

  7. The effects of γ-ray ultrastructure and ethylene biosynthesis in apple pulp cells

    International Nuclear Information System (INIS)

    Ultrastructural changes caused by gamma-ray (Co-60) irradiation were investigated in preclimacteric apple fruits during storage. Under the electron microscope, the cellulose in the cell walls was reduced to a line when treated with 40 Krad gamma radiation for 38 hr, and disappeared completely after treatment with 100 Krad. The disintegration of plasmalemma and mitochondria membranes was observed. Plasmalemma membranes were impaired after 10 Krads for 38 hr, while in the mitochondria the destruction of the original structure and its inner membrane spine began at 40 Krads for 38 hr. Moreover, the size of starch granules was reduced by the irradiation, disappearing after treatment with 100 Krads. Both ethylene production and respiration rate were drastically reduced. The reduction of ethylene production in treated apple fruit was found to be due to the decrease of ACC content and the inhibition of ethylene-forming enzyme activity. MACC content was also decreased. Fruits treated with 40 Krad gamma radiation and stored at 0-2 degrees C maintained their quality for six months

  8. The cell-wall glycoproteins of the green alga Scenedesmus obliquus. The predominant cell-wall polypeptide of Scenedesmus obliquus is related to the cell-wall glycoprotein gp3 of Chlamydomonas reinhardtii.

    Science.gov (United States)

    Voigt, Jürgen; Stolarczyk, Adam; Zych, Maria; Malec, Przemysław; Burczyk, Jan

    2014-02-01

    The green alga Scenedesmus obliquus contains a multilayered cell wall, ultrastructurally similar to that of Chlamydomonas reinhardtii, although its proportion of hydroxyproline is considerably lower. Therefore, we have investigated the polypeptide composition of the insoluble and the chaotrope-soluble wall fractions of S. obliquus. The polypeptide pattern of the chaotrope-soluble wall fraction was strongly modified by chemical deglycosylation with anhydrous hydrogen fluoride (HF) in pyridine indicating that most of these polypeptides are glycosylated. Polypeptide constituents of the chaotrope-soluble cell-wall fraction with apparent molecular masses of 240, 270, 265, and 135 kDa cross-reacted with a polyclonal antibody raised against the 100 kDa deglycosylation product of the C. reinhardtii cell-wall glycoprotein GP3B. Chemical deglycosylation of the chaotrope-soluble wall fraction resulted in a 135 kDa major polypeptide and a 106 kDa minor component reacting with the same antibody. This antibody recognized specific peptide epitopes of GP3B. When the insoluble wall fraction of S. obliquus was treated with anhydrous HF/pyridine, three polypeptides with apparent molecular masses of 144, 135, and 65 kDa were solubilized, which also occured in the deglycosylated chaotrope-soluble wall fraction. These findings indicate that theses glycoproteins are cross-linked to the insoluble wall fraction via HF-sensitive bonds. PMID:24388513

  9. Ultrastructural study of the endothelial cells in teleost liver sinusoids under normal and experimental conditions.

    Science.gov (United States)

    Ferri, S; Sesso, A

    1981-01-01

    The ultrastructure of the endothelial cells of liver sinusoids was studied in the teleost, Pimelodus maculatus. These cells have the ability to form pinocytotic vacuoles, starting with the formation of marginal folds. The latter occur in many cells after stimulation by India ink injections and ink particles are ingested by pinocytosis and by micropinocytosis. Desmosomes, structures rarely described between liver sinusoidal endothelial cells, are present in this species. PMID:7273119

  10. Acute respiratory bronchiolitis: an ultrastructural and autoradiographic study of epithelial cell injury and renewal in Rhesus monkeys exposed to ozone

    International Nuclear Information System (INIS)

    The pathogenesis of acute respiratory bronchiolitis was examined in Rhesus monkeys exposed to 0.8 ppM ozone for 4 to 50 hours. Epithelial injury and renewal were qualitatively and quantitatively characterized by correlated techniques of scanning and transmission electron microscopy as well as by light-microscopic autoradiography following labeling with tritiated thymidine. Extensive degeneration and necrosis of Type 1 epithelial cells occurred on the respiratory bronchiolar wall during the initial 4 to 12 hours of exposure. Increased numbers of labeled epithelial cells were present in this region after 18 hours of exposure, and the highest labeling index (18%) was measured after 50 hours of exposure. Most (67 to 80%) of the labeled cells and all the mitotic epithelial cells (22) observed ultrastructurally were cuboidal bronchiolar epithelial cells. Of the labeled epithelial cells, 20 to 33% were Type 2 epithelial cells. After 50 hours of exposure the respiratory bronchiolar epithelium was hyperplastic. The predominant inflammatory cell in respiratory bronchiolar exudate was the alveolar macrophage. Monkeys that were exposed for 50 hours and allowed to recover in unozonized air for 7 days had incomplete resolution of respiratory bronchiolar epithelial hyperplasia. The results indicate that Type 1 epithelial cells lining respiratory bronchioles are the cell types most sensitive to injury and that both cuboidal bronchiolar epithelial cells and Type 2 epithelial cells function as stem cells in epithelial renewal

  11. Hierarchical structure and dynamics of plant cell wall studied using x-rays

    OpenAIRE

    Svedström, Kirsi

    2012-01-01

    The interest in wood and its main constituent, cellulose, is growing continuously. This can be explained by the demands of sustainable development and the extending scope of applications enabled by novel materials like nanocrystalline cellulose. Outstanding mechanical properties are one of the main reasons for the usability of wood. However, details on the ultrastructure of wood cell wall are still lacking, and thus also the origin for the mechanical properties is partly unknown. The various ...

  12. Ultrastructural characteristics of type A epithelioid cells during BCG-granulomatosis and treatment with lysosomotropic isoniazid.

    Science.gov (United States)

    Shkurupii, V A; Kozyaev, M A; Nadeev, A P

    2006-04-01

    We studied BCG-granulomas, their cellular composition, and ultrastructure of type A epithelioid cells in the liver of male BALB/c mice with spontaneous granulomatous inflammation. The animals received free isoniazid or isoniazid conjugated with lysosomotropic intracellularly prolonged matrix (dialdehyde dextran, molecular weight 65-75 kDa). Lysosomotropic isoniazid was accumulated in the vacuolar apparatus of epithelioid cells and produced a stimulatory effect on plastic processes in these cells. PMID:17152378

  13. Ultrastructure characteristic of the endocrine cells of prostate in poorly differentiated adenocarcinoma

    OpenAIRE

    Prokopyuk O.V.; Volkov K.S.; Kurik O.G.

    2008-01-01

    A research purpose was a ultrastructural study of prostatic APUD-system at poorly differentiated adenocarcinoma. The electron-microscopic investigation of the endocrine cells of prostate in 6 patients with poorly differentiated adenocarcinoma and fragments of 3 prostates without a tumour process (control group) was performed. Both the increase of the morphofunctional activity and presence of dystrophic changes of endocrine cells of prostate was found. At tumours, built from dark cells, APUD-c...

  14. Ultrastructural alterations in human lymphoblastoid B cell lines treated with tunicamycin.

    OpenAIRE

    Glassy, M C; Ferrone, S

    1981-01-01

    The ultrastructure of three human lymphoblastoid B cell lines, Raji, RPMI 4098, and WIL-2, was analyzed after the cells were incubated with tunicamycin, and antibiotic that selectively inhibits N-linked glycosylation of macromolecules. After a 24-hour exposure to 1.0 microgram/ml of tunicamycin, the lymphocytes lose their microvilli and become smooth spheres or develop a few blebs. Also, the cells show a dilation of the endoplasmic reticulum and an increase in myelin figures resulting from in...

  15. Cell wall remodelling enzymes modulate fungal cell wall elasticity and osmotic stress resistance

    OpenAIRE

    Ene, Iuliana; Walker, Louise; Schiavone, Marion; Lee, Keunsook K.; Dague, Etienne; Gow, Neil A.R.; Munro, Carol A

    2015-01-01

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Ce...

  16. Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

    OpenAIRE

    Levin, David E.

    2011-01-01

    The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to...

  17. Architecture of dermatophyte cell Walls: Electron microscopic and biochemical analysis

    Science.gov (United States)

    Nozawa, Y.; Kitajima, Y.

    1984-01-01

    A review with 83 references on the cell wall structure of dermatophytes is presented. Topics discussed include separation and preparation of cell walls; microstructure of cell walls by electron microscopy; chemical composition of cell walls; structural model of cell walls; and morphological structure of cell walls.

  18. Distribution and ultrastructure of Merkel cell of the fishing bat (Myotis ricketti)

    Institute of Scientific and Technical Information of China (English)

    YIN JiangXia; WANG HongMei; RACEY Paul; ZHANG ShuYi

    2009-01-01

    The distribution and ultrastructure of Merkel cells were described in detail in piscivorous bats through immunohistochemistry and transmission electron microscopy techniques. The findings indicated that Merkel cells are commonly found in raised-domes, hair follicles and in the basal epidermis of the skin from their back, abdomen, intercrural membranes, wing membranes and footpads. However, the density of Merkel cells is significantly higher in the footpad than in other places. These results suggested that there may be a link between Merkel cells and tactile sense, and also might imply that raised-domes with air-flow sensitive hairs played an important role in adjusting flying gestures by monitoring the air flow around the body. The ultrastructure of Merkel cells is similar to other vertebrates except having more intermediate filaments and larger granules.

  19. Distribution and ultrastructure of Merkel cell of the fishing bat (Myotis ricketti)

    Institute of Scientific and Technical Information of China (English)

    RACEY; Paul

    2009-01-01

    The distribution and ultrastructure of Merkel cells were described in detail in piscivorous bats through immunohistochemistry and transmission electron microscopy techniques. The findings indicated that Merkel cells are commonly found in raised-domes,hair follicles and in the basal epidermis of the skin from their back,abdomen,intercrural membranes,wing membranes and footpads. However,the density of Merkel cells is significantly higher in the footpad than in other places. These results suggested that there may be a link between Merkel cells and tactile sense,and also might imply that raised-domes with air-flow sensitive hairs played an important role in adjusting flying gestures by monitoring the air flow around the body. The ultrastructure of Merkel cells is similar to other vertebrates except having more intermediate filaments and larger granules.

  20. Ultrastructural and immunocytochemical characterization of interstitial cells in pre- and postnatal developing sheep pineal gland

    Directory of Open Access Journals (Sweden)

    E Redondo

    2009-12-01

    Full Text Available Pineal gland interstitial cells from 32 sheep embryos (from day 54 of gestation until birth and 18 sheep (from 1 month to >2 years were analysed using ultrastructural and immunohistochemical techniques. From day 98 of gestation and throughout postnatal development, a second cell type was observed in addition to pinealocytes; these cells displayed uniform ultrastructural features similar to those of CNS astrocytes. Ultrastructural homogeneity was not matched by the results of histochemical and immunohistochemical analysis. Expression of phosphotungstic acid hematoxylin, glial fibrillary acidic protein and vimentin indicates that the second cell population in the developing ovine pineal gland is, in fact, a combination of glial-astrocyte cells at varying stages of maturity. Pineal interstitial cells started to show signs of functional activity evident in vascular tropism; such activity, evident from around day 98 of gestation, appeared to relate to the exchange of substances between the pineal parenchyma and blood vessels and, though it continued throughout postnatal development, was most evident in animals slaughtered between 9 months and 2 years of age (group II. Morphologically, functional activi- ty in interstitial cells in this age-group was apparent in: 1, formation of specific contact sites between interstitial cells and nerve fibres in the perivascular space; and 2, the presence of numerous gap junctions between the bulbous endings of cytoplasmic processes.

  1. Improved sectioning and ultrastructure of bacteria and animal cells embedded in Lowicryl.

    Science.gov (United States)

    Bénichou, J C; Fréhel, C; Ryter, A

    1990-04-01

    Lowicryl K4M-embedded Gram-positive and Gram-negative bacteria have a tendency to separate between the cell surface and the resin. This often leads to distortion of bacteria and more especially of mycobacteria. We describe attempts made to overcome this technical problem. Different assays were made on Bacillus subtilis, Escherichia coli, and Mycobacterium avium: 1) Modification of the bacterial surface by coating of bacteria with proteinic compounds; 2) treatment of bacteria with metallic salts known to modify cell wall polysaccharides; and 3) comparison between Lowicryl K4M and HM20. Conditions have been found in which the separation of all bacterial species from the resin is abolished. The most important factor appeared to be the treatment of bacteria before dehydration, with 0.5% uranyl acetate for 30 min. The second most important factor, especially for M. avium and to a lower extent for Gram-negative bacteria, was the use of Lowicryl HM20. No differences were observed with Gram-positive bacteria between K4M and HM20. Pre-embedding in gelatin instead of agar improved sectioning of M. avium, but had no effects on the other bacterial species. These conditions applied to macrophages infected with Shigella dysenteriae or M. avium also gave excellent results. In addition to sectioning improvement of bacteria, uranyl acetate improved the ultrastructure of bacteria and macrophages. All organelles were more clearly delineated and, hence, more easily identified. Finally, it was shown that UA treatment did not affect immunogold labeling of a variety of antigens. PMID:2110246

  2. Cell Wall Assembly in Saccharomyces cerevisiae

    OpenAIRE

    Lesage, Guillaume; Bussey, Howard

    2006-01-01

    An extracellular matrix composed of a layered meshwork of β-glucans, chitin, and mannoproteins encapsulates cells of the yeast Saccharomyces cerevisiae. This organelle determines cellular morphology and plays a critical role in maintaining cell integrity during cell growth and division, under stress conditions, upon cell fusion in mating, and in the durable ascospore cell wall. Here we assess recent progress in understanding the molecular biology and biochemistry of cell wall synthesis and it...

  3. The ultrastructure of the kinetochore and kinetochore fiber in Drosophila somatic cells

    OpenAIRE

    Maiato, Helder; Hergert, Polla J.; Moutinho-Pereira, Sara; Dong, Yimin; VandenBeldt, Kristin J.; Rieder, Conly L.; McEwen, Bruce F.

    2006-01-01

    Drosophila melanogaster is a widely used model organism for the molecular dissection of mitosis in animals. However, despite the popularity of this system, no studies have been published on the ultrastructure of Drosophila kinetochores and kinetochore fibers (K-fibers) in somatic cells. To amend this situation, we used correlative light (LM) and electron microscopy (EM) to study kinetochores in cultured Drosophila S2 cells during metaphase, and after colchicine treatment to depolymerize all m...

  4. Ultrastructural characteristics of nurse cell-larva complex of four species of Trichinella in several hosts

    OpenAIRE

    Sacchi L.; Corona S.; Gajadhar A.A.; Pozio E.

    2001-01-01

    The nurse cell-larva complex of nematodes of the genus Trichinella plays an Important role in the survival of the larva in decaying muscles, frequently favouring the transmission of the parasite in extreme environmental conditions. The ultrastructure of the nurse cell-larva complex in muscles from different hosts infected with T. nativa (a walrus and a polar bear), T. spiralis (horses and humans), T. pseudospiralis (a laboratory mouse) and T. papuae (a laboratory mouse) were examined. Analysi...

  5. How do plant cell walls extend?

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

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

  6. Peculiarities of ultrastructure of Chlorella cells growing aboard the Bion-10 during 12 days

    Science.gov (United States)

    Popova, A. F.; Sytnik, K. M.

    The ultrastructure of Chlorella cells grown in darkness on a solid agar medium with organic additions aboard the Bion-1O biosatellite was studied. Certain differences in submicroscopic organization of organelles in the experimental cells were revealed compared to the Earth control. The changes are registered mainly in ultrastructure of energetic organelles - mitochondria and plastids of the experimental cells, in particular, an increase of mitochondria and their cristae size, as well as an increase of the total volume of mitochondrion per cell were established. The decrease of the starch amount in the plastid stroma and the electron density of the latter was also observed. In many experimental cells, the increase of condensed chromatin in the nuclei has been noted. Ultrastructural rearrangements in cells after laboratory experiment realized according to the thermogram registered aboard the Bion-10 were insignificant compared to the flight experiment. Data obtained are compared to results of space flight experiments carried out aboard the Bion-9 (polycomponent aquatic system) and the orbital station Mir (solid agar medium).

  7. Acinar cell ultrastructure after taurine treatment in rat acute necrotizing pancreatitis

    International Nuclear Information System (INIS)

    To evaluate the organelle-based changes in acinar cells in experimental acute necrotizing pancreatitis (ANP) after taurine treatment and the association of electron microscopic findings with histopathalogical changes and oxidative stress markers. The study was performed in February 2005at Gulhane School of Medicine and Hacettepe University, Turkey. Forty-five rats were divided into 3 groups. Acute necrotizing pancreatitis was induced in groups II and III. Groups I and II were treated with saline and Group III with taurine 1000mg/kg/day, i.p, for 48 hours. Histopathological and ultrastructural examinations were determined using one-way analysis of variance and Kruskal-Wallis tests. Histopathologic findings improved significantly after taurine treatment. Degree of injury in rough and smooth endoplasmic reticulums, Golgi apparatus, mitochondria and nucleus of acinar cells also decreased with taurine in correlation with biochemical and histological results. Taurine improves acinar cell organelle structure, and ultrastructural recovery in ANP reflects histological improvement. (author)

  8. Glial cells of the central nervous system of Bothrops jararaca (Reptilia, Ofidae: an ultrastructural study

    Directory of Open Access Journals (Sweden)

    Eduardo F. Bondan

    2015-07-01

    Full Text Available Abstract Although ultrastructural characteristics of mature neuroglia in the central nervous system (CNS are very well described in mammals, much less is known in reptiles, especially serpents. In this context, two specimens of Bothrops jararaca were euthanized for morphological analysis of CNS glial cells. Samples from telencephalon, mesencephalon and spinal cord were collected and processed for light and transmission electron microscopy investigation. Astrocytes, oligodendrocytes, microglial cells and ependymal cells, as well as myelin sheaths, presented similar ultrastructural features to those already observed in mammals and tended to maintain their general aspect all over the distinct CNS regions observed. Morphological similarities between reptilian and mammalian glia are probably linked to their evolutionary conservation throughout vertebrate phylogeny.

  9. 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

    2009-01-01

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

  10. Glycoprotein component of plant cell walls

    International Nuclear Information System (INIS)

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

  11. Cell wall composition of chlorococcal algae

    OpenAIRE

    Blumreisinger, Maria; Meindl, Doris; Loos, Eckhard

    1983-01-01

    The cell walls of representatives of the genera Chlorella, Monoraphidium, Ankistrodesmus and Scenedesmus contained 24–74% neutral sugars, 1–24% uronic acids, 2–16% protein and 0–15% glucosamine. Two types of cell walls could be discerned containing as main sugars either rhamnose and galactose or mannose and glucose with a lack of galactose.

  12. MITOCHONDRIAL DYSFUNCTION AND APOPTOSIS IN TROPHOBLAST CELLS DURING PREECLAMPSIA: AN ULTRASTRUCTURAL STUDY

    Directory of Open Access Journals (Sweden)

    Castejón O

    2011-01-01

    Full Text Available Objective: The aim of this study was to examine the ultrastructure of the mitochondria in trophoblast cells of pregnant women with preeclampsia and to relate it with apoptotic events.Material and methods: Placentas at term were obtained immediately after cesarean delivery. Three biopsies per placenta were taken from the maternal basal surface in the delivery room. Specimens from peripheral ramifications of the villous tree (especially immature intermediate and terminal villi were processed through conventional procedures of transmission electron microscopy and opportunely compared with controls obtained from normal placentas.Results: Ultrastructural degenerative changes in mitochondrial inner membrane and matrix of trophoblast cells (lysis of cristae and matrix vacuolization were visualized. Swollen mitochondria in diverse degenerative grades were found. Two types of degenerated mitochondria in accordance with the mitochondrial matrix were detected in apoptotic trophoblast cells.Conclusion: Mitochondrial ultrastructural changes appear to be the origin of trophoblast cell death by apoptosis. Subsequently, trophoblast debris would fall from placental villi into the intervillous space and could become not only corpuscles damaging the endothelium of the fetal-placental maternal unit but one of the stimuli for endothelial dysfunction and the maintenance of the pathogenesis of preeclampsia.

  13. Ultrastructural study of mouse adipose-derived stromal cells induced towards osteogenic direction.

    Science.gov (United States)

    Tsupykov, Oleg; Ustymenko, Alina; Kyryk, Vitaliy; Smozhanik, Ekaterina; Yatsenko, Kateryna; Butenko, Gennadii; Skibo, Galina

    2016-06-01

    We investigated the ultrastructural characteristics of mouse adipose-derived stem/stromal cells (ASCs) induced towards osteogenic lineage. ASCs were isolated from adipose tissue of FVB-Cg-Tg(GFPU)5Nagy/J mice and expanded in monolayer culture. Flow cytometry, histochemical staining, and electron microscopy techniques were used to characterize the ASCs with respect to their ability for osteogenic differentiation capacity. Immunophenotypically, ASCs were characterized by high expression of the CD44 and CD90 markers, while the relative content of cells expressing CD45, CD34 and CD117 markers was alkaline phosphatase production. Electron microscopy analysis revealed that undifferentiated ASCs had a rough endoplasmic reticulum with dilated cisterns and elongated mitochondria. At the end of the osteogenic differentiation, the ASCs transformed from their original fibroblast-like appearance to having a polygonal osteoblast-like morphology. Ultrastructurally, these cells were characterized by large euchromatic nucleus and numerous cytoplasm containing elongated mitochondria, a very prominent rough endoplasmic reticulum, Golgi apparatus and intermediate filament bundles. Extracellular matrix vesicles of variable size similar to the calcification nodules were observed among collagen fibrils. Our data provide the ultrastructural basis for further studies on the cellular mechanisms involved in osteogenic differentiation of mouse adipose-derived stem/stromal cells. Microsc. Res. Tech. 79:557-564, 2016. © 2016 Wiley Periodicals, Inc. PMID:27087359

  14. WallProtDB, a database resource for plant cell wall proteomics

    OpenAIRE

    San Clemente, Hélène; Jamet, Elisabeth

    2015-01-01

    Background During the last fifteen years, cell wall proteomics has become a major research field with the publication of more than 50 articles describing plant cell wall proteomes. The WallProtDB database has been designed as a tool to facilitate the inventory, the interpretation of cell wall proteomics data and the comparisons between cell wall proteomes. Results WallProtDB (http://www.polebio.lrsv.ups-tlse.fr/WallProtDB/) presently contains 2170 proteins and ESTs identified experimentally i...

  15. Safranine fluorescent staining of wood cell walls.

    Science.gov (United States)

    Bond, J; Donaldson, L; Hill, S; Hitchcock, K

    2008-06-01

    Safranine is an azo dye commonly used for plant microscopy, especially as a stain for lignified tissues such as xylem. Safranine fluorescently labels the wood cell wall, producing green/yellow fluorescence in the secondary cell wall and red/orange fluorescence in the middle lamella (ML) region. We examined the fluorescence behavior of safranine under blue light excitation using a variety of wood- and fiber-based samples of known composition to interpret the observed color differentiation of different cell wall types. We also examined the basis for the differences in fluorescence emission using spectral confocal microscopy to examine lignin-rich and cellulose-rich cell walls including reaction wood and decayed wood compared to normal wood. Our results indicate that lignin-rich cell walls, such as the ML of tracheids, the secondary wall of compression wood tracheids, and wood decayed by brown rot, tend to fluoresce red or orange, while cellulose-rich cell walls such as resin canals, wood decayed by white rot, cotton fibers and the G-layer of tension wood fibers, tend to fluoresce green/yellow. This variation in fluorescence emission seems to be due to factors including an emission shift toward red wavelengths combined with dye quenching at shorter wavelengths in regions with high lignin content. Safranine fluorescence provides a useful way to differentiate lignin-rich and cellulose-rich cell walls without counterstaining as required for bright field microscopy. PMID:18802812

  16. Morphological and ultrastructural changes in vegetative cells and heterocysts of Anabaena variabilis grown with fructose.

    OpenAIRE

    Lang, N. J.; Krupp, J M; Koller, A L

    1987-01-01

    The morphology and ultrastructure of Anabaena variabilis grown in medium with and without 40 mM fructose were compared. Vegetative cells and young heterocysts in fructose-supplemented medium were significantly larger, were filled with glycogen granules, and had fewer thylakoids. Developing heterocysts contained large numbers of glycogen granules well into mature stages, and envelope formation was precocious. As heterocysts enlarged in fructose medium, their shape became more broadly oblong co...

  17. Ultrastructural study of long-term canine distemper virus infection in tissue culture cells.

    OpenAIRE

    Narang, H K

    1982-01-01

    The morphogenesis of canine distemper virus was studied in Vero cell cultures for 43 days post-inoculation. Active replication of the virus was observed by electron microscopy and assay from 12 h after inoculation on, and peak production was observed on days 5, 14, and 22. From day 28 on, constant but smaller amounts of infectious virus were detected. Two ultrastructural types of intracytoplasmic nucleoprotein filaments were observed; although they first appeared at different times, their sub...

  18. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    OpenAIRE

    Márcia de Mello Luvielmo; Caroline Dellinghausen Borges; Daniela de Oliveira Toyama; Claire Tondo Vendruscolo; Adilma Regina Pippa Scamparini

    2016-01-01

    Abstract The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on g...

  19. Effects of 900 MHz electromagnetic radiation on ultrastructure of rats’ hippocampal neural stem cells in vitro

    Directory of Open Access Journals (Sweden)

    Hai-shui LUO

    2012-04-01

    Full Text Available Objective To investigate the effect of 900MHz electromagnetic radiation on the ultrastructure of rat hippocampal neural stem cells (NSCs in vitro in order to provide basic materials for studying the biological effects of electromagnetic wave on the central nervous system. Methods Rat NSCs were divided into sham group, Radi1 group and Radi2 group, and they were respectively exposed to 900 MHz electromagnetic wave at power density of 0, 1, and 3mW/cm2 in vitro. Cells in Radi1 group and Radi2 group were sub-grouped according to the way radiation was given: continuous irradiation, in which cells were exposed on the second day after culture for 2h per day for 6 consecutive days; single exposure to irradiation, in which cells were exposed for 12h on the sixth day after the culture. The ultrastructural changes on the surface of the cells were observed with atomic force microscope (AFM, whereas the ultrastructural changes in the cells were observed with transmission electron microscope (TEM. Results After 900 MHz electromagnetic radiation, when compared with the sham group (0mW/cm2, it was shown that the surface of neural stem cells in the exposure groups (1 and 3mW/cm2 became rough, and there were some changes such as "cavitation" and "fissure formation" in the membrane. The intracellular ultrastructure was found to have obviously disrupted in the exposure groups, such as homogenization of cytoplasm, obvious change organelle structure, morphological damage of structure of nucleus, nuclear membrane disappearance, and chromatin pyknosis, and the changes were more obvious in Radi2 group. Compared with the sham group, the surface roughness (Ra of cells in the exposure group was significantly intensified (P < 0.05, and it was higher in Radi2 group than that in Radi1 group (P < 0.05. Conclusion A 900MHz electromagnetic radiation may cause injury changes in NSCs membrane and ultrastructure in vitro, and the extent of injury may be related to the

  20. Cell wall proteins: a new insight through proteomics

    OpenAIRE

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

    2006-01-01

    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-translation...

  1. An ultrastructural study of cell-cell interactions in capture organs of the nematophagous fungus Arthrobotrys oligospora

    NARCIS (Netherlands)

    Veenhuis, Marten; Nordbring-Hertz, Birgit; Harder, Willem

    1985-01-01

    A detailed ultrastructural analysis was made of interactions between individual cells within the same adhesive network (trap) of the nematophagous fungus Arthrobotrys oligospora. These interactions were confined to traps which had captured nematodes, and occurred concurrently with the fungus-nematod

  2. Autophagy as an ultrastructural marker of heavy metal toxicity in human cord blood hematopoietic stem cells

    International Nuclear Information System (INIS)

    Stem cells are a key target of environmental toxicants, but little is known about their toxicological responses. We aimed at developing an in-vitro model based on adult human stem cells to identify biomarkers of heavy metal exposure. To this end we investigated the responses of human CD34+ hematopoietic progenitor cells to hexavalent chromium (Cr[VI]) and cadmium (Cd). Parallel cultures of CD34+ cells isolated from umbilical cord blood were exposed for 48 h to 0.1 μM and 10 μM Cr(VI) or Cd. Cultures treated with 10 μM Cr(VI) or Cd showed marked cell loss. Ultrastructural analysis of surviving cells revealed prominent autophagosomes/autophagolysosomes, which is diagnostic of autophagy, associated with mitochondrial damage and replication, dilatation of the rough endoplasmic reticulum and Golgi complex, cytoplasmic lipid droplets and chromatin condensation. Treated cells did not show the morphologic hallmarks of apoptosis. Treatment with 0.1 μM Cr(VI) or Cd did not result in cell loss, but at the ultrastructural level cells showed dilated endoplasmic reticulum and evidence of mitochondrial damage. We conclude that autophagy is implicated in the response of human hematopoietic stem cells to toxic concentrations of Cr(VI) and Cd. Autophagy, which mediates cell survival and death under stress, deserves further evaluation to be established as biomarker of metal exposure

  3. GABAergic and glycinergic pathways to goldfish retinal ganglion cells: an ultrastructural double label study

    International Nuclear Information System (INIS)

    An ultrastructural double label has been employed to compare GABAergic and glycinergic systems in the inner plexiform layer (IPL) of the goldfish retina. Electron microscope autoradiography of 3H-GABA and 3H-glycine uptake was combined with retrograde HRP-labeling of ganglion cells. When surveyed for distribution, GABAergic and glycinergic synapses were found onto labeled ganglion cells throughout the IPL. This reinforces previous physiological work that described GABAergic and glycinergic influences on a variety of ganglion cells in goldfish and carp; These physiological effects often reflect direct inputs

  4. Molecular regulation of plant cell wall extensibility

    Science.gov (United States)

    Cosgrove, D. J.

    1998-01-01

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

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

    OpenAIRE

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

    2013-01-01

    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 wa...

  6. Ultrastructural appearance and cytoskeletal architecture of the clear, chromophilic, and chromophobe types of human renal cell carcinoma in vitro.

    OpenAIRE

    Gerharz, C D; Moll, R.; Störkel, S.; Ramp, U; Thoenes, W.; Gabbert, H E

    1993-01-01

    The clear, chromophilic, and chromophobe types of human renal cell carcinoma have been defined as distinct morphological entities and can be clearly separated by differences of ultrastructural appearance, cytoskeletal architecture, enzyme synthesis, and cytogenetic aberrations. In this report, the cytomorphological aspects of these tumor types are compared in vitro, showing that essential ultrastructural and cytoskeletal characteristics of each tumor type are expressed even after prolonged in...

  7. Effects of Shuanghuangbu on the total protein content and ultrastructure in cultured human periodontal ligament cells

    Institute of Scientific and Technical Information of China (English)

    许彦枝; 邹慧儒; 王小玲; 刘世正; 王永军

    2004-01-01

    Background Successful periodontal regeneration depends on the migration, proliferation and differentiation of periodontal ligament cells in periodontal defects. The total protein content and the ultrastructure demonstrate the metabolizability and activity of periodontal ligament cells. This study was conducted to observe the effects of Shuanghuangbu, a mixture of medicinal herbs, on the total protein content and the ultrastructure of human periodontal ligament cells.Methods Periodontal ligament cells were grown to confluence and then cultured in Dulbecco's modified eagle medium (DMEM) supplemented with Shuanghuangbu over the concentration range of 0 to 1000 μg/ml. The total protein content in cultured cells was determined by using Coommasie brilliant blue technique. Periodontal ligament cells were incubated in 0 and 100 μg/ml Shuanghuangbu decoction for 5 days, then observed through transmission electron microscope.Results The total protein content of human periodontal ligament cells increased in each experiment group added 10-1000 μg/ml Shuanghuangbu respectively, and the effect of 100 μg/ml was excellent. Under the transmission electron microscope, there were more rough endoplasmic reticulums and mitochodrias in the experiment group than those in the control group. Conclusion Shuanghuangbu stimulates the protein synthesis of human periodontal ligament cells and improves human periodontal ligament cells' metabolizability and activity.

  8. 2003 Plant Cell Walls Gordon Conference

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Cosgrove

    2004-09-21

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

  9. Refractive index of plant cell walls

    Science.gov (United States)

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

    1974-01-01

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

  10. Ulcerative colitis: ultrastructure of interstitial cells in myenteric plexus

    DEFF Research Database (Denmark)

    Rumessen, Jüri Johs.; Rumessen, J J; Vanderwinden, J-M; Horn, T

    2010-01-01

    degenerative changes, such as lipid droplets and irregular vacuoles. Nerve terminals often appeared swollen and empty. Glial cells, muscle cells, and fibroblast-like cells (FLC) showed no alterations. FLC enclosed macrophages (MLC), which were in close contact with naked axon terminals. The organization and...

  11. Morphological and ultrastructural changes in the cell structure of enterohaemorrhagic Escherichia coli O157:H7 following treatment with Quercus infectoria nut galls.

    Science.gov (United States)

    Suwalak, Sakol; Voravuthikunchai, Supayang P

    2009-10-01

    Some information is available on the oak (Quercus infectoria) nut gall as an effective medicinal plant against Shiga toxin-producing Escherichia coli (STEC) O157:H7. However, its antibacterial mechanisms have not yet been elucidated. In this study, some antibacterial actions against STEC O157:H7 were investigated by observing cell viability as well as morphological and ultrastructural changes. An ethanolic extract of Q. infectoria demonstrated inhibitory and bactericidal effects on all of the strains tested with minimal inhibition concentrations (MICs) at 0.78-1.56 mg ml(-1) and minimal bactericidal concentrations (MBCs) at 1.56-3.12 mg ml(-1). Cell numbers treated with 4MIC of the extract decreased at least two log-fold within 4 h and were completely killed within 12 h. Scanning electron microscopy illustrated a complete loss of surface appendages and pronounced morphological changes at MIC and 2MIC. The whole cell collapsed at 4MIC. Ultrastructural changes from corresponding transmission electron micrographs further verified that damages in the treated cells increased with the increase in the extract concentrations. At MIC (0.78 mg ml(-1)), there was some evidence that the cytoplasmic membranes of the treated E. coli were bulging and/or ruptured, and the cells appeared to be discharging intracellular materials. At 2MIC, the outer membrane of the treated E. coli which was attached to the cell wall became separated from the wall. Disruption in the outer wall and cytoplasmic membranes, especially at the polar regions of the cells occurred and some vacuolization appeared. At 4MIC, the damage to E. coli cells was extensive, and there was loss of their cellular integrity. PMID:19451663

  12. Homogenization of a viscoelastic model for plant cell wall biomechanics

    OpenAIRE

    Ptashnyk, Mariya; Seguin, Brian

    2015-01-01

    The microscopic structure of a plant cell wall is given by cellulose microfibrils embedded in a cell wall matrix. In this paper we consider a microscopic model for interactions between viscoelastic deformations of a plant cell wall and chemical processes in the cell wall matrix. We consider elastic deformations of the cell wall microfibrils and viscoelastic Kelvin--Voigt type deformations of the cell wall matrix. Using homogenization techniques (two-scale convergence and periodic unfolding me...

  13. Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize.

    Science.gov (United States)

    Ren, Baizhao; Cui, Haiyan; Camberato, James J; Dong, Shuting; Liu, Peng; Zhao, Bin; Zhang, Jiwang

    2016-08-01

    A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of mesophyll cell ultrastructure, chloroplast configuration of mesophyll cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in mesophyll cells and the endomembrane system was destroyed, which resulted in the dissolution of cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged mesophyll cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK. PMID:27437706

  14. Nuclear DNA content and ultrastructure of secretory cells of Vicia faba L. stigma

    Directory of Open Access Journals (Sweden)

    Bogdan Wróbel

    2014-02-01

    Full Text Available The object of study was the level of nuclear DNA and the ultrastructural transformations in the secretory cells of the stigma in Vicia faba L. It has been found that the stigmal cells which are active in biogenesis and exudate secretion are diploid cells whose differentiation starts from 2C DNA level. The presence of a population of nuclei with an amount DNA of about 2.5 C suggests that the metabolic activity of those cells may be regulated through supplementary incomplete replication. The ultrastructural transformations of secretory cells point to three stages of biogenesis and secretion of exudate. Stage I, before the start of the cell's secretory functions, is characterized by the development of the protein synthesizing apparatus and the activity of dictyosomes. In development stage II vesicular electron-transparent exudate is secreted. Stage III of exudate biogenesis is production of lipids. They form mainly in the plastids and are secreted with the involvement of the cell's vacuolar system.

  15. Function of laccases in cell wall biosynthesis

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...... 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 the...... 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...

  16. Ultrastructural characteristic of cells and pigment analysis in floating and submerged leaves of Trapa natans L.

    Directory of Open Access Journals (Sweden)

    Оlena M. Nedukha

    2012-03-01

    Full Text Available The comparative analysis of ultrastructure of the photosynthetic cells and pigment content of Trapa natans in both floating and submerged leaves at vegetative phase were conducted. It has shown that the changes of cell ultrasructure and pigment content in leaves are depended from the location of leaves above or under water surface. It has ascertained that submersion of the leaves under water lead to: 1 increase of thylakoid number in grana; 2 decrease of number of the chloroplasts with starch grains; 3 decrease of the relation between chlorophylls (Chlа/ Chlb and of the sum of chlorophylls (Chlа+ Chlb in comparison with analogical parameters in floating leaves

  17. Ultrastructural effects of acute tetraethyllead poisoning on nerve cells of the rabbit brain

    Energy Technology Data Exchange (ETDEWEB)

    Niklowitz, W.J.

    1974-08-01

    A study of the ultrastructural alterations of nerve cell components in specific areas of the brain of the rabbit after acute poisoning with tetraethyllead (TEL). A single dose of 100 mg/kg of TEL caused neurological disorders such as convulsions after a latency of 12 to 18 h. An electron microscopic study revealed that the nerve cells of the areas investigated contained different stages of degenerative changes not demonstrated by light microscopy. These appear to be dependent on location and antedate the neurological disorders. The cytopathogenesis is discussed in the light of these findings and available biochemical data. (CIS Abstract Vol. 2)

  18. Cell wall remodeling under abiotic stress

    OpenAIRE

    Tenhaken, Raimund

    2015-01-01

    Plants exposed to abiotic stress respond to unfavorable conditions on multiple levels. One challenge under drought stress is to reduce shoot growth while maintaining root growth, a process requiring differential cell wall synthesis and remodeling. Key players in this process are the formation of reactive oxygen species (ROS) and peroxidases, which initially cross-link phenolic compounds and glycoproteins of the cell walls causing stiffening. The function of ROS shifts after having converted a...

  19. Structural Insight into Cell Wall Architecture of Micanthus sinensis cv. using Correlative Microscopy Approaches.

    Science.gov (United States)

    Ma, Jianfeng; Lv, Xunli; Yang, Shumin; Tian, Genlin; Liu, Xing'e

    2015-10-01

    Structural organization of the plant cell wall is a key parameter for understanding anisotropic plant growth and mechanical behavior. Four imaging platforms were used to investigate the cell wall architecture of Miscanthus sinensis cv. internode tissue. Using transmission electron microscopy with potassium permanganate, we found a great degree of inhomogeneity in the layering structure (4-9 layers) of the sclerenchymatic fiber (Sf). However, the xylem vessel showed a single layer. Atomic force microscopy images revealed that the cellulose microfibrils (Mfs) deposited in the primary wall of the protoxylem vessel (Pxv) were disordered, while the secondary wall was composed of Mfs oriented in parallel in the cross and longitudinal section. Furthermore, Raman spectroscopy images indicated no variation in the Mf orientation of Pxv and the Mfs in Pxv were oriented more perpendicular to the cell axis than that of Sfs. Based on the integrated results, we have proposed an architectural model of Pxv composed of two layers: an outermost primary wall composed of a meshwork of Mfs and inner secondary wall containing parallel Mfs. This proposed model will support future ultrastructural analysis of plant cell walls in heterogeneous tissues, an area of increasing scientific interest particularly for liquid biofuel processing. PMID:26358178

  20. Ultrastructural analysis of different human mesenchymal stem cells after in vitro expansion: a technical review

    Directory of Open Access Journals (Sweden)

    M. Miko

    2015-10-01

    Full Text Available Transmission electron microscopy reveals ultrastructural details of cells, and it is a valuable method for studying cell organelles. That is why we used this method for detailed morphological description of different adult tissuederived stem cells, focusing on the morphological signs of their functions (proteosynthetic activity, exchange with external environment, etc. and their comparison. Preparing a specimen from the cell culture suitable for transmission electron microscopy is, however, much more challenging than routine tissue processing for normal histological examination. There are several issues that need to be solved while working with cell pellets instead of solid tissue. Here we describe a simple protocol for the isolation and culture of mesenchymal stem cells from different adult tissues, with applications to stem cell biology and regenerative medicine. Since we are working with population of cells that was obtained after many days of passaging, very efficient and gentle procedures are highly necessary. We demonstrated that our semi-conservative approach regarding to histological techniques and processing of cells for transmission electron microscopy is a well reproducible procedure which results in quality pictures and images of cell populations with minimum distortions and artifacts. We also commented about riskiest steps and histochemical issues (e.g., precise pH, temperature while preparing the specimen. We bring full and detailed procedures of fixation, post-fixation, infiltration, embedding, polymerization and contrasting of cell obtained from in vitro cell and tissue cultures, with modifications according to our experience. All this steps are essential for us to know more about adult stem cells derived from different sources or about other random cell populations. The knowledge about detailed ultra-structure of adult stem cells cultured in vitro are also essential for their using in regenerative medicine and tissue engineering.

  1. Ultrastructure of Zika virus particles in cell cultures

    Science.gov (United States)

    Barreto-Vieira, Debora Ferreira; Barth, Ortrud Monika; da Silva, Marcos Alexandre Nunes; Santos, Carolina Cardoso; Santos, Aline da Silva; F, Joaquim Batista; de Filippis, Ana Maria Bispo

    2016-01-01

    Zika virus (ZIKV) has infected thousands of Brazilian people and spread to other American countries since 2015. The introduction of ZIKV brought a strong impact to public health in Brazil. It is of utmost importance to identify a susceptible cell line that will enable the isolation and identification of the virus from patient samples, viral mass production, and testing of drug and vaccine candidates. Besides real-time reverse transcriptase polymerase chain reaction diagnosis for detecting the viral genome, virus isolation in cell lines was useful in order to study the structure of the viral particle and its behaviour inside cells. Analysis of ZIKV infected cell lines was achieved using transmission electron microscopy (TEM). Blood was obtained from a Brazilian patient during the first days after presenting with signs of the disease, and ZIKV from the patient’s blood was isolated in the C6/36 mosquito cell line. Afterwards, Vero cells were inoculated with the viral suspension, fixed six days after inoculation, embedded in polymers, and ultra-thin cut. Like dengue viruses, this flavivirus showed numerous virus particles present inside cellular vesicles thereby confirming the susceptibility of the Vero cell line to ZIKV replication. TEM is a unique technique available to make the virus visible.

  2. Ultrastructure of Zika virus particles in cell cultures.

    Science.gov (United States)

    Barreto-Vieira, Debora Ferreira; Barth, Ortrud Monika; Silva, Marcos Alexandre Nunes da; Santos, Carolina Cardoso; Santos, Aline da Silva; F, Joaquim Batista; Filippis, Ana Maria Bispo de

    2016-08-01

    Zika virus (ZIKV) has infected thousands of Brazilian people and spread to other American countries since 2015. The introduction of ZIKV brought a strong impact to public health in Brazil. It is of utmost importance to identify a susceptible cell line that will enable the isolation and identification of the virus from patient samples, viral mass production, and testing of drug and vaccine candidates. Besides real-time reverse transcriptase polymerase chain reaction diagnosis for detecting the viral genome, virus isolation in cell lines was useful in order to study the structure of the viral particle and its behaviour inside cells. Analysis of ZIKV infected cell lines was achieved using transmission electron microscopy (TEM). Blood was obtained from a Brazilian patient during the first days after presenting with signs of the disease, and ZIKV from the patient's blood was isolated in the C6/36 mosquito cell line. Afterwards, Vero cells were inoculated with the viral suspension, fixed six days after inoculation, embedded in polymers, and ultra-thin cut. Like dengue viruses, this flavivirus showed numerous virus particles present inside cellular vesicles thereby confirming the susceptibility of the Vero cell line to ZIKV replication. TEM is a unique technique available to make the virus visible. PMID:27581122

  3. Cell-wall dynamics in growing bacteria

    Science.gov (United States)

    Furchtgott, Leon; Wingreen, Ned; Huang, Kerwyn Casey

    2010-03-01

    Bacterial cells come in a large variety of shapes, and cell shape plays an important role in the regulation of many biological functions. Cell shape in bacterial cells is dictated by a cell wall composed of peptidoglycan, a polymer made up of long, stiff glycan strands and flexible peptide crosslinks. Although much is understood about the structural properties of peptidoglycan, little is known about the dynamics of cell wall organization in bacterial cells. In particular, during cell growth, how does the bacterial cell wall continuously expand and reorganize while maintaining cell shape? In order to investigate this question quantitatively, we model the cell wall of the Gram-negative bacterium Escherichia coli using a simple elastic model, in which glycan and peptide subunits are treated as springs with different spring constants and relaxed lengths. We consider the peptidoglycan network as a single-layered network of these springs under tension due to an internal osmotic pressure. Within this model, we simulate possible hypotheses for cell growth as different combinations of addition of new springs and breakage of old springs.

  4. Ultrastructural comparison of porcine putative embryonic stem cells derived by in vitro fertilization and somatic cell nuclear transfer

    Science.gov (United States)

    YOO, Hyunju; KIM, Eunhye; HWANG, Seon-Ung; YOON, Junchul David; JEON, Yubyeol; PARK, Kyu-Mi; KIM, Kyu-Jun; JIN, Minghui; LEE, Chang-Kyu; LEE, Eunsong; KIM, Hyunggee; KIM, Gonhyung; HYUN, Sang-Hwan

    2016-01-01

    The ultrastructure of porcine putative embryonic stem cells and porcine fetal fibroblasts (PFFs) was analyzed by transmission electron microscopy. The aim of this study was to compare the features of organelles in in vitro fertilization (IVF) derived porcine embryonic stem cells (IVF-pESCs) and somatic cell nuclear transfer (SCNT) derived pESCs (SCNT-pESCs). Also, the features of organelles in high-passage IVF-pESCs were compared with those in low-passage cells. The ultrastructure of PFFs showed rare microvilli on the cell surfaces, polygonal or irregular nuclei with one to two reticular-shaped nucleoli and euchromatin, low cytoplasm-to-nucleus ratios, rare ribosomes, rare rough endoplasmic reticulum, elongated mitochondria, rich lysosomes and rich phagocytic vacuoles. IVF-pESCs showed rare microvilli on the cell surfaces, round or irregular nuclei with one to two reticular-shaped nucleoli and euchromatin, low cytoplasm-to-nucleus ratios, rich ribosomes, long stacks of rough endoplasmic reticulum, elongated mitochondria, rare lysosomes and rare autophagic vacuoles. By contrast, SCNT-pESCs showed rich microvilli with various lengths and frequencies on the cell surfaces, polygonal nuclei with one reticular shaped nucleoli and heterochromatin, high cytoplasm-to-nucleus ratios, rare ribosomes, rare rough endoplasmic reticulum, round mitochondria, rich lysosomes and rich phagocytic vacuoles with clear intercellular junctions. Furthermore, high-passage IVF-pESCs showed irregularly shaped colonies, pyknosis and numerous lysosomes associated with autophagic vacuoles showing signs of apoptosis. In conclusion, this study confirms that the ultrastructural characteristics of pESCs differ depending on their origin. These ultrastructural characteristics might be useful in biomedical research using pESCs, leading to new insights regarding regenerative medicine and tissue repair. PMID:26821870

  5. Ultrastructure of interstitial cells in subserosa of human colon

    DEFF Research Database (Denmark)

    Rumessen, Jüri Johannes; Vanderwinden, Jean-Marie; Hansen, Alastair;

    2013-01-01

    processes, most densely arranged close to the longitudinal muscle cells. Caveolae, bundles of intermediate filaments and membrane-associated dense bands, often with a patchy basal lamina, were characteristic. Secretory organelles (granular endoplasmic reticulum, smooth endoplasmic reticulum, Golgi, coated...

  6. Adaptive response to starvation in the fish pathogen Flavobacterium columnare: cell viability and ultrastructural changes

    Directory of Open Access Journals (Sweden)

    Arias Covadonga R

    2012-11-01

    Full Text Available Abstract Background The ecology of columnaris disease, caused by Flavobacterium columnare, is poorly understood despite the economic losses that this disease inflicts on aquaculture farms worldwide. Currently, the natural reservoir for this pathogen is unknown but limited data have shown its ability to survive in water for extended periods of time. The objective of this study was to describe the ultrastructural changes that F. columnare cells undergo under starvation conditions. Four genetically distinct strains of this pathogen were monitored for 14 days in media without nutrients. Culturability and cell viability was assessed throughout the study. In addition, cell morphology and ultrastructure was analyzed using light microscopy, scanning electron microscopy, and transmission electron microscopy. Revival of starved cells under different nutrient conditions and the virulence potential of the starved cells were also investigated. Results Starvation induced unique and consistent morphological changes in all strains studied. Cells maintained their length and did not transition into a shortened, coccus shape as observed in many other Gram negative bacteria. Flavobacterium columnare cells modified their shape by morphing into coiled forms that comprised more than 80% of all the cells after 2 weeks of starvation. Coiled cells remained culturable as determined by using a dilution to extinction strategy. Statistically significant differences in cell viability were found between strains although all were able to survive in absence of nutrients for at least 14 days. In later stages of starvation, an extracellular matrix was observed covering the coiled cells. A difference in growth curves between fresh and starved cultures was evident when cultures were 3-months old but not when cultures were starved for only 1 month. Revival of starved cultures under different nutrients revealed that cells return back to their original elongated rod shape upon

  7. Analysis of the changes in the basal cell region of oral lichen planus: An ultrastructural study

    Directory of Open Access Journals (Sweden)

    Mayura Paul

    2013-01-01

    Full Text Available Context: Oral lichen planus (OLP affects 0.5-1% of the total world′s population. The histological features of oral lichen planus were first described by Dubreuill in 1906. Despite the advent of various techniques, the etiology of lichen planus remains obscure, although many theories for the etiology have been proposed. Aims: By studying OLP electron microscopically, we shall be emphasizing on the cells and its interactions in specific/altered surroundings which would help us in hypothesizing the effects of its specific cell-to-cell interactions. Materials and Methods: A total of 20 cases of oral lichen planus were selected and categorized into erosive and nonerosive forms based upon clinical pattern and confirmed as lichen planus by histopathological analysis. Tissue specimens thus obtained were cut into two halves and fixed in appropriate fixatives, i.e., neutral buffered formalin for paraffin-embedded hematoxylin and eosin stained sections and 2.5% glutaraldehyde and 2% paraformaldehyde for electron microscopic purpose respectively. Results: Ultrastructural comparison among the two forms showed significant differences between them. The basal layer showed cytoplasmic processes, intercellular spaces, desmosomes, nuclei, and signs of degeneration. The erosive form showed elongated, narrow or irregular cytoplasmic projections whereas the nonerosive showed short and broad based projections. Conclusions: The present study confirms the ultrastructural findings of basal cells in OLP with previous authors findings. Besides this, the categorization of the ultrastructural differences between erosive and nonerosive has raised the question of difference in the probable cellular and molecular mechanism between erosive and nonerosive forms.

  8. ANF and exocrine pancreas: ultrastructural autoradiographic localization in acinar cells

    International Nuclear Information System (INIS)

    Atrial natriuretic factor (ANF) binding sites have been recently demonstrated to be present in exocrine pancreas by an in vitro autoradiographic approach. An autoradiographic study was carried out to identify the exocrine cells containing ANF binding sites and to monitor the fate of 125I-labeled ANF in acinar cells after removal of pancreas at specific time intervals (1-30 min) after intravenous administration. At the light microscopic level, silver grains were found over acinar and centroacinar cells. Concomitant injection of an excess of unlabeled ANF inhibited the binding of labeled peptide by approximately 60%. At the electron microscopic level, the time-course study in acinar cells has revealed that of the cell compartments examined, plasma membrane, Golgi apparatus, mitochondria, and zymogen granules, the nucleus had distinct labeling patterns. Plasma membrane was maximally labeled 1 and 2 min after injection with 125I-ANF. Golgi apparatus was significantly labeled from 2 to 30 min after injection, mitochondria from 1 to 30 min after injection, zymogen granules at 1 and 15 min, and the nucleus only at 30 min. The lysosomal compartment was not labeled during the 30-min observation period. These results suggest that after binding to the plasma membrane, ANF is rapidly internalized and distributed to the intracellular organelles as a function of time. Labeling of the zymogen granules suggests that they may bind ANF and that the atrial peptide may be secreted by acinar cells. The significance of association of radioactivity with mitochondria and nuclei remains to be elucidated but may represent intracellular sites of action of ANF complementary to those on plasma membranes

  9. Ultrastructural similarity between bat and human mast cell secretory granules.

    Science.gov (United States)

    Oliani, S M; Vugman, I; Jamur, M C

    1993-01-01

    Mast cells in the tongue of the bat (Artibeus lituratus) show a well-developed Golgi area and abundant mitochondria in the granule-free perinuclear cytoplasm. Rough endoplasmic reticulum profiles, free ribosomes, mitochondria, bundles of filaments and a great number of secretory granules are found throughout the remaining cytoplasm. The granules, of various shapes and sizes, are simple containing an electron-dense, homogeneous matrix, coarse particles or cylindrical scrolls, or combinations (cylindrical scrolls with either electron-dense, homogeneous matrix or coarse particle contents). Up to now, scroll-containing granules have been considered to be a unique feature of human mast cells. PMID:8453310

  10. Crohn's disease: ultrastructure of interstitial cells in colonic myenteric plexus

    DEFF Research Database (Denmark)

    Rumessen, Jüri J; Vanderwinden, Jean-Marie; Horn, Thomas

    2011-01-01

    bundles were dilated and appeared to be empty. Lipid droplets and lipofuscin-bodies were prominent in glial cells and neurons. ICC-MP were scanty but, as in controls, had caveolae, prominent intermediate filaments, cytoplasmic dense bodies, and membrane-associated dense bands with a patchy basal lamina...

  11. Ultrastructure of the digestive cells in millipedes (Myriapoda, Diplopoda)

    Czech Academy of Sciences Publication Activity Database

    Kszuk-Jendrysik, M.; Sosinka, A.; Rost-Roszkowska, M.M.; Vilímová, J.; Tajovský, Karel; Poprawa, I.; Hyra, M.; Sonakowska, L.; Kamińska, K.

    Olomouc : Institute of Soil Biology , BC ASCR, 2014. s. 45. ISBN 978-80-86525-28-0. [International Congress of Myriapodology /16./. 20.07.2014-25.07.2014, Olomouc] Institutional support: RVO:60077344 Keywords : millipedes * digestive cells Subject RIV: EG - Zoology

  12. ULTRASTRUCTURAL ASPECTS OF PROGRAMMED CELL DEATH IN THE EXOCARP OIL GLANDS OF MANDARIN (CITRUS DELICIOSA TEN.)

    OpenAIRE

    Artemios Michael BOSABALIDIS

    2014-01-01

    In the exocarp of mandarin fruit (Citrus deliciosa Ten.), numerous globular/ovoid oil glands occur. In the centre of each gland, an essential oil-accumulating cavity is formed by a process of cell lysis. This process is induced by PCD which becomes ultrastructurally evident by the presence of a large number of fragmented ER-elements with a dark content. They appear only at the stage of PCD initiation and they disappear afterwards. ER-elements are scattered over the entire cytoplasmic area and...

  13. "Steiner trees" between cell walls of sisal

    Institute of Scientific and Technical Information of China (English)

    LI GuanShi; YIN YaJun; LI Yan; ZHONG Zheng

    2009-01-01

    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.

  14. Calcium Forms,Subcelluar Distribution and Ultrastructure of Pulp Cells as Influenced by Calcium Deficiency in Apple (Malus pumila) Fruits

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

    Calcium in Red Fuji and Starkrimson apples during storage were fractionated by sequent extracting. Localization and distribution of calcium and influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improved method of potassium pyroantimonate technique. Results indicated that spraying calcium solution on surface of young fruits increased contents of calcium in all forms. During storage, contents of soluble calcium and pectic calcium declined and thosein calcium phosphate, calcium oxalate and calcium silicate increased. Calcium contents of Red Fuji in all forms were higher than those of Starkrimson, indicating that calcium accumulating capability of Red Fuji fruits preceded that of Starkrimson. Under transmission electron microscopy, calcium antimonite precipitates (CaAP) was mainly distributed in cell wall, tonoplast, nuclear membrane and nucleoplasm,much more CaAP deposited in vacuole. Calcium deficiency during storage leads to decrease of CaAP in locations mentioned above, disappearance of compartmentation, and entrance of CaAP to cytoplasm. Transformation from soluble calcium and pectic calcium to calcium phosphate,oxalate and damages of biomembranes structuraly and functionally resulted from calcium deficiency during storage were the crucial causation of physiological disorder.

  15. Ultrastructural analysis of midgut cells from Culex quinquefasciatus (Diptera: Culicidae) larvae resistant to Bacillus sphaericus.

    Science.gov (United States)

    de Melo, Janaina Viana; Vasconcelos, Romero Henrique Teixeira; Furtado, André Freire; Peixoto, Christina Alves; Silva-Filha, Maria Helena Neves Lobo

    2008-12-01

    The larvicidal action of the entomopathogen Bacillus sphaericus towards Culex quinquefasciatus is due to the binary (Bin) toxin present in crystals, which are produced during bacterial sporulation. The Bin toxin needs to recognize and bind specifically to a single class of receptors, named Cqm1, which are 60-kDa alpha-glucosidases attached to the apical membrane of midgut cells by a glycosylphosphatidylinositol anchor. C. quinquefasciatus resistance to B. sphaericus has been often associated with the absence of the alpha-glucosidase Cqm1 in larvae midgut microvilli. In this work, we aimed to investigate, at the ultrastructural level, the midgut cells from C. quinquefasciatus larvae whose resistance relies on the lack of the Cqm1 receptor. The morphological analysis showed that midgut columnar cells from the resistant larvae are characterized by a pronounced production of lipid inclusions, throughout the 4th instar. At the end of this stage, resistant larvae had an increased size and number of these inclusions in the midgut cells, while only a small number were observed in the cells from susceptible larvae. The morphological differences in the midgut cells of resistant larvae found in this work suggested that the lack of the Cqm1 receptor, which also has a physiological role as being an alpha-glucosidase, can be related to changes in the cell metabolism. The ultrastructural effects of Bin toxin on midgut epithelial cells from susceptible and resistant larvae were also investigated. The cytopathological alterations observed in susceptible larvae treated with a lethal concentration of toxin included breakdown of the endoplasmic reticulum, mitochondrial swelling, microvillar disruption and vacuolization. Some effects were observed in cells from resistant larvae, although those alterations did not lead to larval death, indicating that the receptor Cqm1 is essential to mediate the larvicidal action of the toxin. This is the first ultrastructural study to show differences

  16. Ultrastructural effects of radiation on cells and tissues: concluding remarks

    International Nuclear Information System (INIS)

    Concluding remarks which condense the subject matter covered in the preceding series of reports which indicate the complex nature of the biological response to ionizing radiation and the inherent difficulties associated with developing unifying concepts and definitions. The multiplicity of the major response variables, i.e., specimen type, radiation parameters, analytical approach and endpoints measured, is undoubtedly a major problem. In these studies, the specimens analyzed ranged from eucaryotic algae grown in vitro in suspension cultures to brain tissue of cancer patients. Specimens were irradiated with now fewer than seven types of ionizing radiation, which varied both in quality (i.e., high and low LET) and quantity (i.e., doses from 0.1 to 90 Gy). Exposure regimens included single, fractionated, and chronic exposures. Further, there were major differences in the analytical approach employed (e.g., structural and functional assays) and end-points measured (e.g., lethality, cell growth, surface topography, etc.)

  17. Ultrastructure of Kupffer cells and hepatocytes in the Dubin-Johnson syndrome: A case report

    Institute of Scientific and Technical Information of China (English)

    Maria Elzbieta Sobaniec-Lotowska; Dariusz Marek Lebensztejn

    2006-01-01

    Ultrastructure of Kupffer cells and hepatocytes in liver bioptate was evaluated in a 17-year-old boy with Dubin -Johnson syndrome (DJS). The liver tissue obtained by needle biopsy was fixed in glutaraldehyde and paraformaldehyde and routinely processed for electron microscopic analysis. The ultrastructural examinations of liver bioptate revealed the accumulation of membranebound, electron-dense lysosomal granules within the cytoplasm of hepatocytes, characteristic of DJS. They were located mainly in the vicinity of the biliary pole, and preferentially in the centrilobular region that corresponded to the pigment deposits seen under light microscope. The presence of the granules was accompanied by dilated elements of the granular endoplasmic reticulum and paracrystalline mitochondrial inclusions as well as dilation of the bile canaliculi. The changes in hepatocytes coexisted with marked stimulation and enhanced phagocytic activity of Kupffer cells. This was manifested in the accumulation of pigment deposits within their cytoplasm that corresponded to those observed in hepatocytes.Hyperactive pericentral Kupffer cells which are involved in the response to pigmentary material originating from disintegrated hepatocytes may play an essential role in the development of DJS.

  18. Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

    DEFF Research Database (Denmark)

    Hansen, G H; Belhage, B; Schousboe, A;

    1987-01-01

    The temporal development of the effect of THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) on the ultrastructure composition and GABA receptor expression in cerebellar granule cells was investigated by quantitative electron microscopy (morphometric analysis) and GABA binding assays. It was...... exposed to THIP (150 microM) for 3 hr low affinity GABA receptors were induced. These findings show that the effect of THIP on the ultrastructure composition and GABA receptor expression in cultured cerebellar granule cells may be interrelated and moreover it is likely that the turn-over of GABA receptors...

  19. He-Ne laser irradiation causes changes in mitochondria ultrastructure in successive generations of yeast cells

    International Nuclear Information System (INIS)

    Changes in the mitochondria ultrastructural organization in the Torulopsis sphaerica yeast cells, cultivated in 18 hours after irradiation by the He-Ne laser, are studied. Two doses - 460 and 1150 J/m2 were chosen, while irradiation in low doses optimally stimulates the given culture growth (the biomass increases up to 141.2 %). The studies were conducted on the cells of 4-5 generation after irradiation. It is shown, that laser irradiation in the yeast cells effects the ATP-ase synthesis not only through the mechanism of fast respiratory control but also through the synthesis of mitochondrial fermentation complexes (slow respiratory control), which is regulated at the genetic level

  20. Ultrastructural characteristics of nurse cell-larva complex of four species of Trichinella in several hosts

    Directory of Open Access Journals (Sweden)

    Sacchi L.

    2001-06-01

    Full Text Available The nurse cell-larva complex of nematodes of the genus Trichinella plays an Important role in the survival of the larva in decaying muscles, frequently favouring the transmission of the parasite in extreme environmental conditions. The ultrastructure of the nurse cell-larva complex in muscles from different hosts infected with T. nativa (a walrus and a polar bear, T. spiralis (horses and humans, T. pseudospiralis (a laboratory mouse and T. papuae (a laboratory mouse were examined. Analysis with transmission electron microscope showed that the typical nurse cell structure was present in all examined samples, irrespective of the species of larva, of the presence of a collagen capsule, of the age of infection and of the host species, suggesting that there exists a molecular mechanism that in the first stage of larva invasion is similar for encapsulated and non-encapsulated species.

  1. ULTRASTRUCTURAL ASPECTS OF PROGRAMMED CELL DEATH IN THE EXOCARP OIL GLANDS OF MANDARIN (CITRUS DELICIOSA TEN.

    Directory of Open Access Journals (Sweden)

    Artemios Michael BOSABALIDIS

    2014-12-01

    Full Text Available In the exocarp of mandarin fruit (Citrus deliciosa Ten., numerous globular/ovoid oil glands occur. In the centre of each gland, an essential oil-accumulating cavity is formed by a process of cell lysis. This process is induced by PCD which becomes ultrastructurally evident by the presence of a large number of fragmented ER-elements with a dark content. They appear only at the stage of PCD initiation and they disappear afterwards. ER-elements are scattered over the entire cytoplasmic area and do not locally aggregate or associate with other cell organelles and particularly the vacuoles. TEM observations favour the interpretation that ER involves in PCD of oil gland cells by releasing hydrolytic enzymes directly to the cytosol.

  2. Comparison of pigment cell ultrastructure and organisation in the dermis of marble trout and brown trout, and first description of erythrophore ultrastructure in salmonids.

    Science.gov (United States)

    Djurdjevič, Ida; Kreft, Mateja Erdani; Sušnik Bajec, Simona

    2015-11-01

    Skin pigmentation in animals is an important trait with many functions. The present study focused on two closely related salmonid species, marble trout (Salmo marmoratus) and brown trout (S. trutta), which display an uncommon labyrinthine (marble-like) and spot skin pattern, respectively. To determine the role of chromatophore type in the different formation of skin pigment patterns in the two species, the distribution and ultrastructure of chromatophores was examined with light microscopy and transmission electron microscopy. The presence of three types of chromatophores in trout skin was confirmed: melanophores; xanthophores; and iridophores. In addition, using correlative microscopy, erythrophore ultrastructure in salmonids was described for the first time. Two types of erythrophores are distinguished, both located exclusively in the skin of brown trout: type 1 in black spot skin sections similar to xanthophores; and type 2 with a unique ultrastructure, located only in red spot skin sections. Morphologically, the difference between the light and dark pigmentation of trout skin depends primarily on the position and density of melanophores, in the dark region covering other chromatophores, and in the light region with the iridophores and xanthophores usually exposed. With larger amounts of melanophores, absence of xanthophores and presence of erythrophores type 1 and type L iridophores in the black spot compared with the light regions and the presence of erythrophores type 2 in the red spot, a higher level of pigment cell organisation in the skin of brown trout compared with that of marble trout was demonstrated. Even though the skin regions with chromatophores were well defined, not all the chromatophores were in direct contact, either homophilically or heterophilically, with each other. In addition to short-range interactions, an important role of the cellular environment and long-range interactions between chromatophores in promoting adult pigment pattern

  3. Roles of membrane trafficking in plant cell wall dynamics

    OpenAIRE

    Ebine, Kazuo; Ueda, Takashi

    2015-01-01

    The cell wall is one of the characteristic components of plant cells. The cell wall composition differs among cell types and is modified in response to various environmental conditions. To properly generate and modify the cell wall, many proteins are transported to the plasma membrane or extracellular space through membrane trafficking, which is one of the key protein transport mechanisms in eukaryotic cells. Given the diverse composition and functions of the cell wall in plants, the transpor...

  4. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Pawlowski, A.; Persad, S.D.; Menon, I.A.; Haberman, H.F.

    1988-01-01

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells.

  5. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    International Nuclear Information System (INIS)

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells

  6. Ultrastructural proof of polyomavirus in Merkel cell carcinoma tumour cells and its absence in small cell carcinoma of the lung.

    Directory of Open Access Journals (Sweden)

    Charlotte T A H Wetzels

    Full Text Available BACKGROUND: A new virus called the Merkel Cell Polyomavirus (MCPyV has recently been found in Merkel Cell Carcinoma (MCC. MCC is a rare aggressive small cell neuroendocrine carcinoma primarily derived from the skin, morphologically indistinguishable from small cell lung carcinoma (SCLC. So far the actual presence of the virus in MCC tumour cells on a morphological level has not been demonstrated, and the presence of MCPyV in other small cell neuroendocrine carcinomas has not been studied yet. METHODOLOGY/PRINCIPAL FINDINGS: We investigated MCC tissue samples from five patients and SCLCs from ten patients for the presence of MCPyV-DNA by PCR and sequencing. Electron microscopy was used to search ultrastructurally for morphological presence of the virus in MCPyV-DNA positive samples. MCPyV was detected in two out of five primary MCCs. In one MCC patient MCPyV-DNA was detected in the primary tumour as well as in the metastasis, strongly suggesting integration of MCPyV in the cellular DNA of the tumour in this patient. In the primary MCC of another patient viral particles in tumour cell nuclei and cytoplasm were identified by electron microscopy, indicating active viral replication in the tumour cells. In none of the SCLCs MCPyV-DNA was detected. CONCLUSIONS/SIGNIFICANCE: Our results strongly suggest that MCPyV is an oncogenic polyomavirus in humans, and is potentially causally related to the development of MCC but not to the morphological similar SCLC.

  7. Quantitative description of a teleost exocrine pancreas. Ultrastructural morphometric study of nonstimulated acinar cells.

    Science.gov (United States)

    Stipp, A C; Ferri, S; Sesso, A

    1984-01-01

    The quantitative analysis of exocrine pancreas was fulfilled in teleost fish ( Pimelodus maculatus). The volume fraction occupied by acinar cells, blood vessels and ducts has been assessed by point-counting volumetry in 0.25 micron araldite sections. Measurements of the diameters of the transections of acinar cells nuclei and nucleolus allowed the assessment of the mean nuclear and nucleolar volume according to the method of Bach (1963). With these data, the cytoplasm nuclei and nucleolus volume was calculated in cubic micrometers. Morphometric ultrastructural data was obtained by applying over the electronmicrophotographs (X 21,000) a test system of 84 segments regularly spaced one from another (Weibel 1966). The results obtained was analysed and compared to the mammalian. PMID:6721199

  8. The ultrastructure of tumor cells in patients with rectal cancer after pre-operative irradiation and intra-operative cryotherapy

    International Nuclear Information System (INIS)

    Electronic microscopy of the tumor cells was performed to confirm the efficacy of combined pre-operative gamma-therapy and intraoperative cryotherapy (CT). Pre-operative irradiation at the dose of 20 Gy accompanied by intra-operative cryotherapy caused the changes in the ultrastructure, the depth and degree of which allow to consider them destructive and irreversible

  9. Characterization of the Sclerotinia sclerotiorum cell wall proteome.

    Science.gov (United States)

    Liu, Longzhou; Free, Stephen J

    2016-08-01

    We used a proteomic analysis to identify cell wall proteins released from Sclerotinia sclerotiorum hyphal and sclerotial cell walls via a trifluoromethanesulfonic acid (TFMS) digestion. Cell walls from hyphae grown in Vogel's glucose medium (a synthetic medium lacking plant materials), from hyphae grown in potato dextrose broth and from sclerotia produced on potato dextrose agar were used in the analysis. Under the conditions used, TFMS digests the glycosidic linkages in the cell walls to release intact cell wall proteins. The analysis identified 24 glycosylphosphatidylinositol (GPI)-anchored cell wall proteins and 30 non-GPI-anchored cell wall proteins. We found that the cell walls contained an array of cell wall biosynthetic enzymes similar to those found in the cell walls of other fungi. When comparing the proteins in hyphal cell walls grown in potato dextrose broth with those in hyphal cell walls grown in the absence of plant material, it was found that a core group of cell wall biosynthetic proteins and some proteins associated with pathogenicity (secreted cellulases, pectin lyases, glucosidases and proteases) were expressed in both types of hyphae. The hyphae grown in potato dextrose broth contained a number of additional proteins (laccases, oxalate decarboxylase, peroxidase, polysaccharide deacetylase and several proteins unique to Sclerotinia and Botrytis) that might facilitate growth on a plant host. A comparison of the proteins in the sclerotial cell wall with the proteins in the hyphal cell wall demonstrated that sclerotia formation is not marked by a major shift in the composition of cell wall protein. We found that the S. sclerotiorum cell walls contained 11 cell wall proteins that were encoded only in Sclerotinia and Botrytis genomes. PMID:26661933

  10. Cell Wall Heterogeneity in Root Development of Arabidopsis.

    Science.gov (United States)

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

    2016-01-01

    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

  11. Ultrastructural Observation of the Skin Chloride Cells of Japanese Flounder Paralichthys olivaceus and Turbot Scophthamus maximus Larvae

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The ultrastructures of skin chloride cells in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride cells were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride cells of euryhaline fish gill. They locate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying network of tubules. The degeneration of skin chloride cells is observed with development of Japanese flounder larvae. Skin chloride cells of turbot are less developmental than those of Japanese flounder in the same developmental stage.

  12. Functional canine dendritic cells can be generated in vitro from peripheral blood mononuclear cells and contain a cytoplasmic ultrastructural marker.

    Science.gov (United States)

    Ibisch, C; Pradal, G; Bach, J M; Lieubeau, B

    2005-03-01

    For physiological and practical reasons the dog is a large animal model used increasingly to study the pathogenesis of human diseases and new therapeutic approaches, in particular for immune disorders. However, some immunological resources are lacking in this model, especially concerning dendritic cells. The aim of our study was to develop an efficient method to generate dendritic cells (DC) in vitro from dog peripheral blood mononuclear cells (PBMC) and to characterize their functional, structural and ultrastructural properties. PBMC were cultured in vitro with IL-4 and GM-CSF. After 1 week of culture, a great proportion of non-adherent cells displayed typical cytoplasmic processes, as evidenced both by optical and electron microscopy. Cytometric analysis revealed the presence of 41.7+/-24.6% CD14+ cells expressing both CD11c and MHC class II molecules. Allogeneic mixed lymphocyte reactions confirmed the ability of these cultures to stimulate the proliferation of allogeneic lymphocytes as already reported as a characteristic of DC in other species. In addition, we describe for the first time the presence in canine DC of cytoplasmic periodic microstructures (PMS) that could represent ultrastructural markers of canine DC. In conclusion, our study provides an easy method to generate DC from PBMC in sufficient numbers for immunological in vitro investigations in dogs, a pre-clinical model for many human diseases. PMID:15847807

  13. 3D Ultrastructural Organization of Whole Chlamydomonas reinhardtii Cells Studied by Nanoscale Soft X-Ray Tomography

    OpenAIRE

    Hummel, Eric; Guttmann, Peter; Werner, Stephan; Tarek, Basel; SCHNEIDER, Gerd; Kunz, Michael; Frangakis, Achilleas S.; Westermann, Benedikt

    2012-01-01

    The complex architecture of their structural elements and compartments is a hallmark of eukaryotic cells. The creation of high resolution models of whole cells has been limited by the relatively low resolution of conventional light microscopes and the requirement for ultrathin sections in transmission electron microscopy. We used soft x-ray tomography to study the 3D ultrastructural organization of whole cells of the unicellular green alga Chlamydomonas reinhardtii at unprecedented spatial re...

  14. 3D ultrastructural organization of whole Chlamydomonas reinhardtii cells studied by nanoscale soft x-ray tomography

    OpenAIRE

    Hummel, Eric; Guttmann, Peter; Werner, Stephan; Tarek, Basel; SCHNEIDER, Gerd; Kunz, Michael; Frangakis, Achilleas S.; Westermann, Benedikt

    2012-01-01

    The complex architecture of their structural elements and compartments is a hallmark of eukaryotic cells. The creation of high resolution models of whole cells has been limited by the relatively low resolution of conventional light microscopes and the requirement for ultrathin sections in transmission electron microscopy. We used soft x-ray tomography to study the 3D ultrastructural organization of whole cells of the unicellular green alga Chlamydomonas reinhardtii at unprecedented spatial re...

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

    OpenAIRE

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

    1982-01-01

    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 ...

  16. Hippocampal ultrastructural changes and apoptotic cell death in rats following endurance training and acute exhaustive exercise

    Institute of Scientific and Technical Information of China (English)

    Jianjun Zhang

    2008-01-01

    BACKGROUND: Exhaustive exercise can lead to apoptosis of skeletal muscle cells and myocardial cells as a result of pathological changes in the corresponding cellular ultrastructure. It is hypothesized that such changes could also occur in neurons. OBJECTIVE: To observe brain cell apoptosis and ultrastmctural changes in hippocampal neurons in rats following endurance training and acute exhaustive exercise. DESIGN, TIME AND SETTING: A randomized, controlled, morphological analysis was performed at the Medical Laboratory Center of Zhengzhou University between July and November 2007. MATERIALS: Forty male, 8-week-old, Sprague Dawley rats were included in this study. METHODS: Endurance training consisted of treadmill running once a day, 6 days a week, for 4 weeks. For acute exhaustive exercise, graded treadmill running was conducted. Rats were exposed to exercise at an increasing speed (10 m/min, increasing to 20 and 36 m/min for moderate- and high-intensity exhaustive exercise, respectively, and then was continued until exhaustion). A total of 40 rats were evenly distributed into the following 4 groups: Group A-rats were not exercised; Group B- rats were not trained but sacrificed 24 hours after acute exhaustive treadmill running exercise; Group C rats were subjected to endurance training and sacrificed immediately after acute exhaustive treadmill running exercise; Group D-rats were subjected to endurance training and sacrificed 24 hours after acute exhaustive treadmill running exercise. MAIN OUTCOME MEASURES: Apoptotic cell death was detected by the TUNEL method and hippocampal neuronal ultrastructural change was observed through using transmission electron microscopy. RESULTS: All 40 rats were included in the final analysis. Subsequent to exhaustive exercise, rat cerebral cortex and hippocampal neurons appeared contracted and degenerated. In addition, high amount of lipofuscin was visible in the hippocampal region. Necrotic neurons encased by glial cells appeared in

  17. Ultrastructural study of the mast cells of the human duodenal mucosa.

    Science.gov (United States)

    Moneret-Vautrin, D A; de Korwin, J D; Tisserant, J; Grignon, M; Claudot, N

    1984-09-01

    The ultrastructure of the process of degranulation of mast cells of human duodenal mucosa was examined. In normal controls little degranulation was seen, but in persons with false food allergy (pseudo-allergy) considerable degranulation of mast cells was detected. This is consistent with the hypothesis that some persons have an abnormal fragility of duodenal mast cells in the presence of histamine-releasing substances. Incubation of duodenal biopsy material with various histamine-releasing agents (compound 48/80, Concanavalin A, the calcium ionophore A 23187, and anti-IgE) confirmed the susceptibility of duodenal mast cells for antigen non-specific release of histamine, or that mediated by IgE. In a group of patients with immediate-type, anaphylactic, food allergy, mast cells in the absence of antigen are in a normal state, but degranulation occurs on exposure in vitro or in vivo to specific antigen. The susceptibility to degranulation continues in persons cured of their food allergy. This suggests that a clinical cure is not due to a change of susceptibility of duodenal mast cells to release histamine, but is possibly associated with formation of blocking antibodies, and/or a modification in reactivity of basophils and mast cells of other organs. PMID:6207955

  18. Fluorescent tags to explore cell wall structure and dynamics

    OpenAIRE

    Gonneau, Martine; Höfte, Herman; Vernhettes, Samantha

    2012-01-01

    Plant cell walls are highly dynamic and heterogeneous structures, which vary between cell types, growth stages but also between microdomains within a single cell wall. In this review, we summarize the imaging techniques using fluorescent tags that are currently being used and which should in the coming years revolutionize our understanding of the dynamics of cell wall architecture and the cellular processes involved in the synthesis of cell wall components.

  19. Measuring in vitro extensibility of growing plant cell walls.

    Science.gov (United States)

    Cosgrove, Daniel J

    2011-01-01

    This article summarizes the theory and practical aspects of measuring cell wall properties by four different extensometer techniques and how the results of these methods relate to the concept and ideal measurement of cell wall extensibility in the context of cell growth. These in vivo techniques are particularly useful for studies of the molecular basis of cell wall extension. Measurements of breaking strength, elastic compliance, and plastic compliance may be informative about changes in cell wall structure, whereas measurements of wall stress relaxation and creep are sensitive to both changes in wall structure and wall-loosening processes, such as those mediated by expansins and some lytic enzymes. A combination of methods is needed to obtain a broader view of cell wall behavior and properties connected with the concept of cell wall extensibility. PMID:21222092

  20. 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

    2009-01-01

    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.

  1. Morphological and ultrastructural characteristics of extracellular matrix changes in oral squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Usha Agrawal

    2011-01-01

    Full Text Available Background: The biology of oral squamous cell carcinoma (OSCC, including its progression from dysplasia to carcinoma, "field effects", genetic changes in tumor associated mucosa (TAM and effect of matrix metalloproteinases in breaking down of matrix proteins to facilitate invasion, has been well documented. However, what remains to be done is to extrapolate this knowledge to improve patient care. Aim: The aim of this study was to observe the extracellular matrix (ECM changes with the routine histochemical stains available to most histopathologists. Materials and Methods: The study includes 72 cases of OSCC in which the tumor and adjacent normal appearing areas were sampled to study the ECM changes with hematoxylin and eosin (H and E and Verhoeff′s-Van Gieson elastic stain (VVG. Results: Basophilic fragmentation of collagen (H and E and clumped short elastic fibers (VVG were seen in 12 (16.7% cases. Of the remaining cases, 18 (25% had a dense lymphocytic infiltrate and had no demonstrable elastic fibers. Those cases with H and E changes were further studied and compared with normal mucosa for ultrastructural changes. The ultrastructural study demonstrated an increase in oxytalan, elaunin and elastic fibers and decrease in collagen fibers with some transformation changes associated with OSCCs and lymph node metastasis. Conclusion: Changes in transformation of collagen to elastic fibers and also the loss of both the fibers in areas of lymphocytic infiltration possibly indicate degradation of ECM fibers by factors released from the lymphocytes or tumor cells and the limiting effect on the tumor by ECM remodeling.

  2. Occurrence and ultrastructural characterization of bacteria in association with and isolated from Azolla caroliniana.

    OpenAIRE

    Nierzwicki-Bauer, S A; Aulfinger, H

    1991-01-01

    The occurrence and ultrastructure of bacteria in leaf cavities of symbiotic Azolla caroliniana were examined by transmission electron microscopy. Bacteria were observed in all leaf cavities of Azolla cultures. Five ultrastructurally distinct types of bacteria were observed in each individual leaf cavity. Features used to characterize the bacteria included morphology, cell wall structure, and cytoplasmic organization. At least one gram-positive and as many as four gram-negative types of bacter...

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  4. Effects of long-term space condition on cell ultrastructure and the molecular level change of the tomato

    Science.gov (United States)

    Jinying, L.; Min, L.; Huai, X.; Yi, P.; Chunhua, Z.; Nechitalo, G.

    Effects of long-term exposure to physical factors of space flight on dormant seeds were studied on plants derived from tomato seeds flown for 6 years on board of the space station MIR Upon return to the Earth the seeds were germinated and grown to maturity Samples of plants were compared to plants from parallel ground-based controls Various differences of ultrastructure of the tomato leaf cell were observed with an electron microscope One plant carried by space station has the anatomy of leaves with a three-layered palisade tissue and other plants similar with ground controls have the anatomy of leaves with a one-layered palisade tissue The number of starch grains per chloroplast of every space-treated tomato leaf increased significantly compared with that of the ground control The leaf cell walls of two plants carried by space station became contracted and deformed The size of chloroplast in some space-treated plants was larger and the lamellae s structure of some chloroplasts turned curvature and loose The results obtained point out to significant changes occurring on the molecular level among the space-flight treated seedlings and the ground control The leaves of plants were used for AFLP Amplification Fragment Length Polymorphism analysis For the first generation space-flight treated tomato plants among 64 pairs of primers used in this experiment 43 primers generated the same DNA bands type and 21 primers generated a different DNA band type 2582 DNA bands were produced among which 34 DNA bands were polymorphic with the percentage

  5. Structure-property relationships in vegetable cell wall suspensions

    OpenAIRE

    Sankaran, Ashwin Karthik

    2015-01-01

    Plant cell wall suspensions are widely present in daily food, such as soups, dressings and sauces. Cell walls of edible plants are made up of an intricate biopolymer network of mainly cellulose microfibrils, pectins, and hemicelluloses. Foodsnbsp;as soups, ketchup, etc are made up of cell wall components. Modern processing methods alter the chemical and physical nature of the cell wall which in turn affect the properties of the end product. There is a need in the industry to build a fundament...

  6. Bio-based composites that mimic the plant cell wall

    OpenAIRE

    Li, Zhuo

    2009-01-01

    Nature creates high performance materials under modest conditions, i.e., neutral pH and ambient temperature and pressure. One of the most significant materials is the plant cell wall. The plant cell wall is a composite of oriented cellulose microfibrils reinforcing a lignin/hemicellulose matrix. In principle, the plant cell wall composite is designed much like a synthetic fiber-reinforced polymer composite. Unlike synthetic composites, the plant cell wall has an excellent combination of h...

  7. Fluorescent tags to explore cell wall structure and dynamics.

    OpenAIRE

    Martine eGonneau; Herman eHöfte; Samantha eVernhettes

    2012-01-01

    Plant cell walls are highly dynamic and heterogeneic structures, which vary between celltypes, growth stages but also between microdomains within a single cell wall. In this review, we summarize the imaging techniques using fluorescent tags that are currently being used and which should in the coming years revolutionize our understanding of the dynamics of cell wall architecture and the cellular processes involved in synthesis of cell wall components.

  8. 阿米卡星致聋大鼠鼓阶壁上皮超微结构的改变%Ultrastructural changes of epithelium on wall of scala tympani in rats with Amikacin induced hearing loss

    Institute of Scientific and Technical Information of China (English)

    李登科; 赵立东; 孙建和; 刘慧占; 杨仕明

    2012-01-01

    Objective To investigate ultrastructural changes of epithelium attached to the bony wall of scala tympani in rat cochleae after amikacin sulfate administration and the structural basis for migration of transplanted mouse embryonic stem cells. Methods Rats were randomly divided into an experiment group (n=20) and a control group(n=10).For rats in the experiment group, amikacin sulfate was injected hypodermically at a dose of 200 mg/kg/day for seven days, while rats in the control group received physiological saline of the same volume instead. The cochlea was removed on Od, 7d, 14, 21d and 28d after amikacin administration was finished. Cochlea on one randomly selected side was prepared for SEM observation and the other co-chlear for HE examination. Results Amikacin sulfate administred to rats induced hearing loss. Epithelia on the bony wall of scala tympani underwent serial ultrastructural changes, including inflammatory exudation and increase of the intercellular spaces, which recovered in a time dependent manner. Conclusion Besides injury and loss of the hair cells in the Organ of Corti, amikacin sulfate treatment can also induce ultrastructural changes on the bony wall of scala tympani which may be the structural base for transplanted stem cell migration from scala tympani in the cochlea. Our results show the time window for inner ear stem cell therapy after ototoxic drugs injury.%目的 观察大鼠经氨基糖苷类抗生素硫酸阿米卡星注射致聋后,耳蜗鼓阶壁上皮超微结构的改变;探索干细胞移植进入鼓阶后,干细胞在内耳发生迁移的结构基础.方法 出生7天的SD大鼠30只,随机分为实验组(20只)与对照组(10只).实验组连续7天经腹腔按照200mg/kg/day的剂量腹腔注射硫酸阿米卡星注射液;对照组注射相同体积的生理盐水.在停药后0天、7天、14天、21天、28天取耳蜗组织,随机选择其中一侧行扫描电镜观察耳蜗底回鼓阶的上皮的变化,另一侧耳蜗

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-31

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

  10. Ultrastructure and histochemistry of rat myocardial capillary endothelial cells in response to diabetes and hypertension

    Institute of Scientific and Technical Information of China (English)

    Ludmila OKRUHLICOVA; Narcis TRIBULOVA; Peter WEISMANN; Ruzena SOTNIKOVA

    2005-01-01

    Insufficient growth and rarefaction of capillaries,followed by endothelial dysfunction may represent one of the most critical mechanisms involved in heart damage.In this study we examined histochemical and ultrastructural changes in myocardial capillary endothelium in two models of heart failure streptozotocin-induced diabetes mellitus (STZ) and NOdeficient hypertension in male Wistar rats.Diabetes was induced by a single i.v.dose of STZ (45 mg/kg) and chronic 9-week stage was analysed.To induce NO-deficient hypertension,animals were treated with inhibitor of NO synthase Lnitroarginine methylester (L-NAME) (40 mg/kg) for 4 weeks.Left ventricular tissue was processed for enzyme catalytic histochemistry of capillary alkaline phosphatase (AlPh),dipeptidyl peptidase Ⅳ (DPP Ⅳ),and endothelial NO synthase/NADPH-diaphorase (NOS) and for ultrastructural analysis.In diabetic and hypertensive rats,lower/absent AlPh and DPP Ⅳ activities were found in focal micro-areas.NOS activity was significantly reduced and persisted only locally.Quantitative evaluation demonstrated reduction of reaction product intensity of AlPh,DPP and NOS by 49.50%,74.36%,20.05% in diabetic and 62.93%,82.71%,37.65% in hypertensive rats.Subcellular alterations of endothelial cells were found in heart of both groups suggesting injury of capillary function as well as compensatory processes.Endothelial injury was more significant in diabetic animals,in contrast the adaptation was more evident in hypertensive ones.Concluding: both STZ-induced diabetes- and NO-deficient hypertension-related cardiomyopathy were accompanied by similar features of structural remodelling of cardiac capillary network manifested as angiogenesis and angiopathy.The latter was however,predominant and may accelerate disappearance of capillary endothelium contributing to myocardial dysfunction.

  11. Effects of Waterlogging on Leaf Mesophyll Cell Ultrastructure and Photosynthetic Characteristics of Summer Maize.

    Science.gov (United States)

    Ren, Baizhao; Zhang, Jiwang; Dong, Shuting; Liu, Peng; Zhao, Bin

    2016-01-01

    A field experiment was performed to study the effects of waterlogging on the leaf mesophyll cell ultrastructure, chlorophyll content, gas exchange parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content of summer maize (Zea mays L.) hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The waterlogging treatments were implemented for different durations (3 and 6 days) at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT). Leaf area index (LAI), chlorophyll content, photosynthetic rate (Pn), and actual photochemical efficiency (ΦPSII) were reduced after waterlogging, indicating that waterlogging significantly decreased photosynthetic capacity. The chloroplast shapes changed from long and oval to elliptical or circular after waterlogging. In addition, the internal structures of chloroplasts were degenerated after waterlogging. After waterlogging for 6 d at V3, the number of grana and grana lamellae of the third expanded leaf in DH605 were decreased by 26.83% and 55.95%, respectively, compared to the control (CK). Those in ZD958 were reduced by 30.08% and 31.94%, respectively. Waterlogging increased MDA content in both hybrids, suggesting an impact of waterlogging on membrane integrity and thus membrane deterioration. Waterlogging also damaged the biological membrane structure and mitochondria. Our results indicated that the physiological reactions to waterlogging were closely related to lower LAI, chlorophyll content, and Pn and to the destruction of chloroplast ultrastructure. These negative effects resulted in the decrease of grain yield in response to waterlogging. Summer maize was the most susceptible to damage when waterlogging occurred at V3, followed by V6 and 10VT, with damage increasing in the wake of waterlogging duration increasing. PMID:27583803

  12. Wall relaxation and the driving forces for cell expansive growth

    Science.gov (United States)

    Cosgrove, D. J.

    1987-01-01

    When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

  13. Plant cell wall dynamics and wall-related susceptibility in plant–pathogen interactions

    OpenAIRE

    Bellincampi, Daniela; Cervone, Felice; Lionetti, Vincenzo

    2014-01-01

    The cell wall is a dynamic structure that often determines the outcome of the interactions between plants and pathogens. It is a barrier that pathogens need to breach to colonize the plant tissue. While fungal necrotrophs extensively destroy the integrity of the cell wall through the combined action of degrading enzymes, biotrophic fungi require a more localized and controlled degradation of the cell wall in order to keep the host cells alive and utilize their feeding structures. Also bacteri...

  14. Plant cell wall dynamics and wall-related susceptibility in plant-pathogen interactions

    OpenAIRE

    Daniela eBellincampi; Felice eCervone; Vincenzo eLionetti

    2014-01-01

    The cell wall is a dynamic structure that often determines the outcome of the interactions between plants and pathogens. It is a barrier that pathogens need to breach to colonize the plant tissue. While fungal necrotrophs extensively destroy the integrity of the cell wall through the combined action of degrading enzymes, biotrophic fungi require a more localized and controlled degradation of the cell wall in order to keep the host cells alive and utilize their feeding structures. Also bacteri...

  15. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    Science.gov (United States)

    de Mello Luvielmo, Márcia; Borges, Caroline Dellinghausen; de Oliveira Toyama, Daniela; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  16. Inflammation and Cell Death in Age-Related Macular Degeneration: An Immunopathological and Ultrastructural Model.

    Science.gov (United States)

    Ardeljan, Christopher P; Ardeljan, Daniel; Abu-Asab, Mones; Chan, Chi-Chao

    2014-01-01

    The etiology of Age-related Macular Degeneration (AMD) remains elusive despite the characterization of many factors contributing to the disease in its late-stage phenotypes. AMD features an immune system in flux, as shown by changes in macrophage polarization with age, expression of cytokines and complement, microglial accumulation with age, etc. These point to an allostatic overload, possibly due to a breakdown in self vs. non-self when endogenous compounds and structures acquire the appearance of non-self over time. The result is inflammation and inflammation-mediated cell death. While it is clear that these processes ultimately result in degeneration of retinal pigment epithelium and photoreceptor, the prevalent type of cell death contributing to the various phenotypes is unknown. Both molecular studies as well as ultrastructural pathology suggest pyroptosis, and perhaps necroptosis, are the predominant mechanisms of cell death at play, with only minimal evidence for apoptosis. Herein, we attempt to reconcile those factors identified by experimental AMD models and integrate these data with pathology observed under the electron microscope-particularly observations of mitochondrial dysfunction, DNA leakage, autophagy, and cell death. PMID:25580276

  17. Structure of xanthan gum and cell ultrastructure at different times of alkali stress.

    Science.gov (United States)

    Luvielmo, Márcia de Mello; Borges, Caroline Dellinghausen; Toyama, Daniela de Oliveira; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  18. Ultrastructure and phylogeny of Glugea nagelia sp. n. (Microsporidia: Glugeidae), infecting the intestinal wall of the yellowfin hind, Cephalopholis hemistiktos (Actinopterygii: Serranidae), from the Red Sea.

    Science.gov (United States)

    Abdel-Baki, Abdel-Azeem S; Al-Quraishy, Saleh; Rocha, Sonia; Dkhil, Mohamed A; Casal, Graca; Azevedo, Carlos

    2015-01-01

    A new microsporidian species of the genus Glugea Thélohan, 1891 parasitising the marine teleost fish Cephalopholis hemistiktos Rüppell, collected from the Red Sea in Saudi Arabia, is described on the basis of microscopic and molecular procedures. Spherical and whitish xenoma were observed adhering to the intestinal wall. The numerous spores contained within these xenoma, were ovoid to pyriform and measured 4.3-6.0 µm (5.1 µm) in length and 1.8-2.9 µm (2.2 µm) in width. The spore's wall was composed of two thick layers, which were thinner in the area contacting the anchoring disk. The latter appeared at the spore's anterior pole, in an eccentric position to the longitudinal axis. A lamellar polaroplast surrounded the uncoiled portion of the polar filament projected to the basal region of the spore, giving rise to 26-29 turns with winding from the base to the anterior zone of the spore. The posterior vacuole, located at the spore's posterior pole, and surrounded by the polar filament coils, was irregular and composed of light material. Molecular analysis of the rRNA genes, including the ITS region, was performed using maximum parsimony, neighbour-joining and maximum likelihood methods. The ultrastructural features observed, combined with the phylogenetic data analysed, suggest this parasite to be a new species of the genus Glugea. This is the first species of this genus to be reported from Saudi Arabia and is herein named Glugea nagelia sp. n. PMID:25960551

  19. Ultrastructural and immunohistochemical studies on Trichomonas vaginalis adhering to and phagocytizing genitourinary epithelial cells

    Institute of Scientific and Technical Information of China (English)

    陈文列; 陈金富; 钟秀容; 梁平; 林炜

    2004-01-01

    Background Trichomonas vaginalis (T. vaginalis) belongs to a common sexually transmitted disease pathogen causing genitourinary trichomoniasis in both sexes. We investigated the pathogenetic mechanism of genitourinary trichomoniasis.Methods Cultured T. vaginalis bodies were injected into the vaginas of rats, or incubated with genitourinary epithelial cells of female subjects, male subjects, and sperm. The ultrastructural and microscopic changes were observed via transmission and scanning electron microscopy and through microscopic histochemistry.Results Groups of T.vaginalis adhered to PAS positive columnar cells at the surface of stratified epithelium in the middle and upper portions of the vaginas. They also traversed under these cells. The parasites were shown to be PAS, cathepsin D, and actin positive, and they could release hydrolase into the cytoplasm of adhered epithelial cells. In the amebiform T.vaginalis, microfilaments were arranged into reticular formation. Similar phenomena were found during the interaction of T.vaginalis with host cells, both in vitro and in vivo. Usually several protozoa adhered to an epithelial cell and formed polymorphic pseudopodia or surface invaginations to surround and phagocytize the microvilli or other parts of the epithelial cytoplasm. Adhesion and phagocytosis of sperm by the protozoa occurred at 15-30 minutes of incubation. Digestion of sperm was found at 45-75 minutes and was complete at 90-105 minutes.Conclusions T.vaginalis tends to parasitize at the fornix of the vagina, because this is the site where columnar cells are rich in mucinogen granules and their microvilli are helpful for adhesion and nibbling. T.vaginalis possesses some invading and attacking abilities. Shape change, canalization, encystation, phagocytosis, digestion, the cell coat, cytoskeleton, and lysosome all play important roles in the process of adhesion. They have two methods of phagocytosis: nibbling and ingestion. Genitourinary epithelium may be

  20. Integrin VLA-3: ultrastructural localization at cell-cell contact sites of human cell cultures

    OpenAIRE

    1989-01-01

    The integrin VLA-3 is a cell surface receptor, which binds to fibronectin, laminin, collagen type I and VI (Takada, Y., E. A. Wayner, W. G. Carter, and M. E. Hemler. 1988. J. Cell. Biochem. 37:385-393) and is highly expressed in substrate adherent cultures of almost all human cell types. The ligand specificity of VLA-3 and the inhibition of cell adhesion by anti-VLA-3 monoclonal antibodies suggest its involvement in cell-substrate interaction. In normal tissues, VLA-3 is restricted to few cel...

  1. Glycosytransferases involved in arabinosylation of cell wall extensins

    DEFF Research Database (Denmark)

    Petersen, Bent L; Harholt, Jesper; Jørgensen, Bodil;

    2011-01-01

    Extensins are a group of ancient hydroxyproline rich cell wall glycoproteins that are found in some chlorophyte algae (such as Chlamydomonas), where they constitute the main wall building block, as well as in higher plant cell walls, where they constitute a relatively minor component of particular...

  2. The effect of irradiation on the cell ultrastructure of the shoot apical meristem in garlic

    International Nuclear Information System (INIS)

    Irradiation with doses of 0.02-0.3 kGy of γ-rays could cause varied damages to the cellular and subcellular structures of the shoot apical meristems in garlic. The irradiated cells were elongated and cell walls were thickened. The highest radio-sensitivity was found in the vacuoles which developed morphological abnormality before the end of dormancy, while the nuclei and nucleoli, which remained intact even after the cell walls were broken, demonstrated the highest resistance to irradiation. The observed morphological damages were of higher magnitude in sprouting period than that in dormancy in which irradiation treatments were conducted, suggesting that metabolism plays an important role in the development of initial irradiation lesions into structural damages in the cells

  3. Effect of anisotonic NaCl treatment on cellular ultrastructure of V79 Chinese hamster cells

    International Nuclear Information System (INIS)

    The ultrastructural modifications produced by anisotonic NaCl treatment of Chinese hamster mitotic cells were observed at three NaCl concentrations which have been frequently used in radiosensitization studies: 0.05, 0.5 and 1.5 M. After exposureto 0.05 M NaCl, many well-spread chromosomes are visible. The chromatin fibres are well dispersed and membraneous material is associated with the chromosomes. After hypertonic treatment with 0.5 M NaCl, the chromosomes have a uniform, structureless appearance with some coalescing into larger anaphase-like masses. At 1.5 M NaCl, large scale cellular dehydration is apparent, and filamentous structures such as microfilaments are tightly constricted. The degree of chromosome staining is also reduced below the level of the cytoplasm. After both hypo- and hypertonic NaCl treatment the chromosomes appear swollen relative to untreated cells, but hypertonic treatment causes chromosome clumping and dissociates chromatin. Conformational changes in the chromatin may restrict the capacity for DNA repair and be related to cellular radiosensitivity. (author)

  4. Cell wall integrity signaling and innate immunity in plants

    OpenAIRE

    Nühse, Thomas S.

    2012-01-01

    All plant pathogens and parasites have had to develop strategies to overcome cell walls in order to access the host’s cytoplasm. As a mechanically strong, multi-layered composite exoskeleton, the cell wall not only enables plants to grow tall but also protects them from such attacks. Many plant pathogens employ an arsenal of cell wall degrading enzymes, and it has long been thought that the detection of breaches in wall integrity contributes to the induction of defense. Cell wall fragments ar...

  5. Enzymes and other agents that enhance cell wall extensibility

    Science.gov (United States)

    Cosgrove, D. J.

    1999-01-01

    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.

  6. Anthocyanins influence tannin-cell wall interactions.

    Science.gov (United States)

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

    2016-09-01

    The rate of tannin extraction was studied in a vinification of red grapes and the results compared with another vinification made with white grapes fermented as for typical red wine, in the presence of skins and seeds. Even though the grapes presented a quite similar skin and seed tannin content, the differences in tannin concentration between both vinifications was very large, despite the fact that the only apparent difference between the phenolic composition of both wines was the anthocyanin content. This suggests that anthocyanins play an important role in tannin extractability, perhaps because they affect the extent of the tannin-cell wall interaction, a factor that largely controls the resulting quantity of tannins in wines. To confirm this observation, the effect of anthocyanins on the tannin extractability from grape seeds and skin and on the interaction between tannins and grape cell walls suspended in model solutions were studied. The results indicated that anthocyanins favored skin and seed tannin extraction and that there is a competition for the adsorption sites between anthocyanins and tannins that increases the tannin content when anthocyanins are present. PMID:27041322

  7. Disruption of hydrogen bonding between plant cell wall polymers by proteins that induce wall extension.

    Science.gov (United States)

    McQueen-Mason, S; Cosgrove, D J

    1994-07-01

    Plant cell enlargement is controlled by the ability of the constraining cell wall to expand. This ability has been postulated to be under the control of polysaccharide hydrolases or transferases that weaken or rearrange the loadbearing polymeric networks in the wall. We recently identified a family of wall proteins, called expansins, that catalyze the extension of isolated plant cell walls. Here we report that these proteins mechanically weaken pure cellulose paper in extension assays and stress relaxation assays, without detectable cellulase activity (exo- or endo- type). Because paper derives its mechanical strength from hydrogen bonding between cellulose microfibrils, we conclude that expansins can disrupt hydrogen bonding between cellulose fibers. This conclusion is further supported by experiments in which expansin-mediated wall extension (i) was increased by 2 M urea (which should weaken hydrogen bonding between wall polymers) and (ii) was decreased by replacement of water with deuterated water, which has a stronger hydrogen bond. The temperature sensitivity of expansin-mediated wall extension suggests that units of 3 or 4 hydrogen bonds are broken by the action of expansins. In the growing cell wall, expansin action is likely to catalyze slippage between cellulose microfibrils and the polysaccharide matrix, and thereby catalyze wall stress relaxation, followed by wall surface expansion and plant cell enlargement. PMID:11607483

  8. In situ microscopy reveals reversible cell wall swelling in kelp sieve tubes: one mechanism for turgor generation and flow control?

    Science.gov (United States)

    Knoblauch, Jan; Tepler Drobnitch, Sarah; Peters, Winfried S; Knoblauch, Michael

    2016-08-01

    Kelps, brown algae (Phaeophyceae) of the order Laminariales, possess sieve tubes for the symplasmic long-distance transport of photoassimilates that are evolutionarily unrelated but structurally similar to the tubes in the phloem of vascular plants. We visualized sieve tube structure and wound responses in fully functional, intact Bull Kelp (Nereocystis luetkeana [K. Mertens] Postels & Ruprecht 1840). In injured tubes, apparent slime plugs formed but were unlikely to cause sieve tube occlusion as they assembled at the downstream side of sieve plates. Cell walls expanded massively in the radial direction, reducing the volume of the wounded sieve elements by up to 90%. Ultrastructural examination showed that a layer of the immediate cell wall characterized by circumferential cellulose fibrils was responsible for swelling and suggested that alginates, abundant gelatinous polymers of the cell wall matrix, were involved. Wall swelling was rapid, reversible and depended on intracellular pressure, as demonstrated by pressure-injection of silicon oil. Our results revive the concept of turgor generation and buffering by swelling cell walls, which had fallen into oblivion over the last century. Because sieve tube transport is pressure-driven and controlled physically by tube diameter, a regulatory role of wall swelling in photoassimilate distribution is implied in kelps. PMID:26991892

  9. Simultaneous ultrastructural analysis of fluorochrome-photoconverted diaminobenzidine and gold immunolabeling in cultured cells

    Directory of Open Access Journals (Sweden)

    M. Malatesta

    2013-09-01

    Full Text Available Diaminobenzidine photoconversion is a technique by which a fluorescent dye is transformed into a stably insoluble, brown, electrondense signal, thus enabling examination at both bright field light microscopy and transmission electron microscopy. In this work, a procedure is proposed for combining photoconversion and immunoelectron microscopy: in vitro cell cultures have been first submitted to photoconversion to analyse the intracellular fate of either fluorescent nanoparticles or photosensitizing molecules, then processed for transmission electron microscopy; different fixative solutions and embedding media have been used, and the ultrathin sections were finally submitted to post-embedding immunogold cytochemistry. Under all conditions the photoconversion reaction product and the target antigen were properly detected in the same section; Epon-embedded, osmicated samples required a pre-treatment with sodium metaperiodate to unmask the antigenic sites. This simple and reliable procedure exploits a single sample to simultaneously localise the photoconversion product and a variety of antigens allowing a specific identification of subcellular organelles at the ultrastructural level.

  10. Biochemistry and cell ultrastructure changes during senescence of Beta vulgaris L. leaf.

    Science.gov (United States)

    Romanova, Alla K; Semenova, Galina A; Ignat'ev, Alexander R; Novichkova, Natalia S; Fomina, Irina R

    2016-05-01

    The comparative study of biochemical and ultrastructure features in senescing sugar beet (Beta vulgaris L.) leaves was carried out. One group of plants was grown under normal conditions in washed river sand and poured in turn with nitrate-containing mineral solution or water (N plants). Another group of plants, after 1 month of normal growth, was further grown with nitrate omitted in the nutritive solution (defN plants). The starting point of normal leaf senescence in N plants was identified by the maximal content of soluble protein. Soluble carbohydrate pools were statistically constant in senescing N plants, whereas glucose pools varied noticeably. A decrease in the contents of soluble protein and chlorophyll (a + b) in the course of senescing was typical for N plant leaves. The cell membrane in N plant leaves remained mostly intact; the central vacuoles in the leaf cells were large, and their membranes remained intact. The chloroplasts and mitochondria in senescing N plant leaves became swollen. The vesicles that were present in the cytoplasm of N plant leaves were especially large in the oldest leaves. It was concluded that senescing of sugar beet leaves at sufficient nitrate nutrition occurs according to a "vacuolar" scenario. In the case of nitrate deficiency, the content of soluble carbohydrates in defN leaves first reached maximum and then decreased in older leaves; the protein and chlorophyll (a + b) contents were totally lower than those in normal leaves and continuously decreased during the experiments. Chloroplasts in mesophyll cells of defN plant leaves became more rounded; starch grains in chloroplasts degraded and the number and size of lipid globules increased. The multitude of membrane impairments and lots of large vesicles-"crystals" appeared during the experiment. The results showed the controlling action of nitrogen nutrition in the senescing of sugar beet leaves. PMID:26666552

  11. Two endogenous proteins that induce cell wall extension in plants

    Science.gov (United States)

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

    1992-01-01

    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.

  12. 3D Ultrastructural organization of whole Chlamydomonas reinhardtii cells studied by nanoscale soft x-ray tomography.

    Directory of Open Access Journals (Sweden)

    Eric Hummel

    Full Text Available The complex architecture of their structural elements and compartments is a hallmark of eukaryotic cells. The creation of high resolution models of whole cells has been limited by the relatively low resolution of conventional light microscopes and the requirement for ultrathin sections in transmission electron microscopy. We used soft x-ray tomography to study the 3D ultrastructural organization of whole cells of the unicellular green alga Chlamydomonas reinhardtii at unprecedented spatial resolution. Intact frozen hydrated cells were imaged using the natural x-ray absorption contrast of the sample without any staining. We applied different fiducial-based and fiducial-less alignment procedures for the 3D reconstructions. The reconstructed 3D volumes of the cells show features down to 30 nm in size. The whole cell tomograms reveal ultrastructural details such as nuclear envelope membranes, thylakoids, basal apparatus, and flagellar microtubule doublets. In addition, the x-ray tomograms provide quantitative data from the cell architecture. Therefore, nanoscale soft x-ray tomography is a new valuable tool for numerous qualitative and quantitative applications in plant cell biology.

  13. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    cannot really be synthesised or sequenced. The work described in this thesis is focused to a large extent on the development of a microarray-based high-throughput method for cell wall analysis known as Comprehensive microarray polymer profiling or CoMPP. The procedure uses highly specific molecular...... 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......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...

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

    OpenAIRE

    Hilz, H

    2007-01-01

    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 enzymes most efficiently, the structure and composition of the cell walls had to be known. This thesis describes a detailed composition of the cell walls of bilberries and black currants. The obtained ...

  15. Melanin is an essential component for the integrity of the cell wall of Aspergillus fumigatus conidia

    Directory of Open Access Journals (Sweden)

    Georgeault Sonia

    2009-08-01

    Full Text Available Abstract Background Aspergillus fumigatus is the most common agent of invasive aspergillosis, a feared complication in severely immunocompromised patients. Despite the recent commercialisation of new antifungal drugs, the prognosis for this infection remains uncertain. Thus, there is a real need to discover new targets for therapy. Particular attention has been paid to the biochemical composition and organisation of the fungal cell wall, because it mediates the host-fungus interplay. Conidia, which are responsible for infections, have melanin as one of the cell wall components. Melanin has been established as an important virulence factor, protecting the fungus against the host's immune defences. We suggested that it might also have an indirect role in virulence, because it is required for correct assembly of the cell wall layers of the conidia. Results We used three A. fumigatus isolates which grew as white or brown powdery colonies, to demonstrate the role of melanin. Firstly, sequencing the genes responsible for biosynthesis of melanin (ALB1, AYG1, ARP1, ARP2, ABR1 and ABR2 showed point mutations (missense mutation, deletion or insertion in the ALB1 gene for pigmentless isolates or in ARP2 for the brownish isolate. The isolates were then shown by scanning electron microscopy to produce numerous, typical conidial heads, except that the conidia were smooth-walled, as previously observed for laboratory mutants with mutations in the PKSP/ALB1 gene. Flow cytometry showed an increase in the fibronectin binding capacity of conidia from mutant isolates, together with a marked decrease in the binding of laminin to the conidial surface. A marked decrease in the electronegative charge of the conidia and cell surface hydrophobicity was also seen by microelectrophoresis and two-phase partitioning, respectively. Ultrastructural studies of mutant isolates detected considerable changes in the organisation of the conidial wall, with the loss of the outermost

  16. Effects of reserpine on ECL-cell ultrastructure and histamine compartmentalization in the rat stomach.

    Science.gov (United States)

    Zhao, C M; Chen, D; Lintunen, M; Panula, P; Håkanson, R

    1999-01-01

    The histamine-storing ECL cells in the stomach play a key role in the control of acid secretion. They contain granules, secretory vesicles and microvesicles, and sustained gastrin stimulation results in the additional formation of vacuoles and lipofuscin bodies. The cells are rich in the vesicle monoamine transporter type-2 (VMAT-2), which can be inhibited by reserpine. The present study examines the effect of reserpine on ECL-cell ultrastructure and histamine compartmentalization. Rats received reserpine and/or gastrin. Reserpine was given twice by the intraperitoneal route (25 mg/kg once daily). Gastrin-17 was given by subcutaneous infusion (5 nmol/kg/h), starting at the time of the first reserpine injection and continuing for 4 days when the rats were killed. At this stage, histamine in the oxyntic mucosa was unaffected by reserpine but elevated by gastrin. Immunocytochemical analysis (confocal microscopy) showed ECL-cell histamine in control and gastrin-treated rats to be localized in cytoplasmic organelles (e.g., secretory vesicles). After treatment with reserpine alone or reserpine+gastrin, ECL-cell histamine occurred mainly in the cytosol. Planimetric analysis (electron microscopy) of ECL cells showed reserpine to increase the number, size and volume density of the granules and to reduce the size and volume density of the secretory vesicles. Gastrin reduced the number and volume density of granules and secretory vesicles, increased the number and volume density of microvesicles and caused vacuoles and lipofuscin bodies to appear. Reserpine+gastrin increased the number, volume density and size of the granules. Reserpine prevented the effects of gastrin on secretory vesicles, vacuoles and microvesicles, but did not prevent the development of lipofuscin. Our findings are in line with the views: (1) that preformed cytosolic histamine is taken up by granules/secretory vesicles via VMAT-2, that histamine is instrumental in the transformation of granules into

  17. Composition of lignin in outer cell-wall layers

    OpenAIRE

    Christiernin, Maria

    2006-01-01

    The composition of lignin in the outer cell-wall layers of spruce and poplar has been studied and the data obtained have been compared with those of the mature reference wood in which the secondary cell wall predominates. Materials with exclusively or predominantly outer cell-wall layers were examined. Accurate data relating to the lignin monomer composition and the number of β-O-4´ bonds were obtained from pure middle lamella/primary cell wall lignin. Firstly, a 10 000 year old white spruce ...

  18. Cosegregation of cell wall and DNA in Bacillus subtilis.

    OpenAIRE

    Schlaeppi, J M; Karamata, D

    1982-01-01

    Cosegregation of cell wall and DNA of a lysis-negative mutant of Bacillus subtilis was examined by continuously labeling (i) cell wall, (ii) DNA, and (iii) both cell wall and DNA. After four to five generations of chase in liquid media it was found by light microscope autoradiography that the numbers of wall segregation units per cell are 29 and 9 in rich and minimal medium, respectively. Under the same conditions the numbers of segregation units of DNA were almost 50% lower: 15 and 5, respec...

  19. Cell wall sorting of lipoproteins in Staphylococcus aureus.

    OpenAIRE

    Navarre, W W; Daefler, S; Schneewind, O

    1996-01-01

    Many surface proteins are thought to be anchored to the cell wall of gram-positive organisms via their C termini, while the N-terminal domains of these molecules are displayed on the bacterial surface. Cell wall anchoring of surface proteins in Staphylococcus aureus requires both an N-terminal leader peptide and a C-terminal cell wall sorting signal. By fusing the cell wall sorting of protein A to the C terminus of staphylococcal beta-lactamase, we demonstrate here that lipoproteins can also ...

  20. Identification and Ultrastructural Characterization of a Novel Nuclear Degradation Complex in Differentiating Lens Fiber Cells.

    Science.gov (United States)

    Costello, M Joseph; Brennan, Lisa A; Mohamed, Ashik; Gilliland, Kurt O; Johnsen, Sönke; Kantorow, Marc

    2016-01-01

    An unresolved issue in structural biology is how the encapsulated lens removes membranous organelles to carry out its role as a transparent optical element. In this ultrastructural study, we establish a mechanism for nuclear elimination in the developing chick lens during the formation of the organelle-free zone. Day 12-15 chick embryo lenses were examined by high-resolution confocal light microscopy and thin section transmission electron microscopy (TEM) following fixation in 10% formalin and 4% paraformaldehyde, and then processing for confocal or TEM as described previously. Examination of developing fiber cells revealed normal nuclei with dispersed chromatin and clear nucleoli typical of cells in active ribosome production to support protein synthesis. Early signs of nuclear degradation were observed about 300 μm from the lens capsule in Day 15 lenses where the nuclei display irregular nuclear stain and prominent indentations that sometimes contained a previously undescribed macromolecular aggregate attached to the nuclear envelope. We have termed this novel structure the nuclear excisosome. This complex by confocal is closely adherent to the nuclear envelope and by TEM appears to degrade the outer leaflet of the nuclear envelope, then the inner leaflet up to 500 μm depth. The images suggest that the nuclear excisosome separates nuclear membrane proteins from lipids, which then form multilamellar assemblies that stain intensely in confocal and in TEM have 5 nm spacing consistent with pure lipid bilayers. The denuded nucleoplasm then degrades by condensation and loss of structure in the range 600 to 700 μm depth producing pyknotic nuclear remnants. None of these stages display any classic autophagic vesicles or lysosomes associated with nuclei. Uniquely, the origin of the nuclear excisosome is from filopodial-like projections of adjacent lens fiber cells that initially contact, and then appear to fuse with the outer nuclear membrane. These filopodial

  1. Cell wall structure and biogenesis in Aspergillus species.

    Science.gov (United States)

    Yoshimi, Akira; Miyazawa, Ken; Abe, Keietsu

    2016-09-01

    Aspergillus species are among the most important filamentous fungi from the viewpoints of industry, pathogenesis, and mycotoxin production. Fungal cells are exposed to a variety of environmental stimuli, including changes in osmolality, temperature, and pH, which create stresses that primarily act on fungal cell walls. In addition, fungal cell walls are the first interactions with host cells in either human or plants. Thus, understanding cell wall structure and the mechanism of their biogenesis is important for the industrial, medical, and agricultural fields. Here, we provide a systematic review of fungal cell wall structure and recent findings regarding the cell wall integrity signaling pathways in aspergilli. This accumulated knowledge will be useful for understanding and improving the use of industrial aspergilli fermentation processes as well as treatments for some fungal infections. PMID:27140698

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

    OpenAIRE

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

    2011-01-01

    Plant cells have a rigid cell wall that constrains internal turgor pressure yet extends in a regulated and organized manner to allow the cell to acquire shape. The primary load-bearing macromolecule of a plant cell wall is cellulose, which forms crystalline microfibrils that are organized with respect to a cell's function and shape requirements. A primary cell wall is deposited during expansion whereas secondary cell wall is synthesized post expansion during differentiation. A complex form of...

  3. Measurement of streptococcal cell wall in tissues of rats resistant or susceptible to cell wall-induced chronic erosive arthritis.

    OpenAIRE

    Anderle, S K; Allen, J B; Wilder, R L; Eisenberg, R A; Cromartie, W J; Schwab, J. H.

    1985-01-01

    The quantity of streptococcal cell wall localized in the joints of rats of strains which are either susceptible (Sprague-Dawley, LEW/N, M520/N) or resistant (Buffalo, WKY/N, F344/N) to cell wall-induced chronic erosive arthritis was measured after intraperitoneal injection of group A streptococcal cell wall fragments. Susceptibility or resistance was not associated with a difference in the amount of cell wall localized in limbs or other tissues. It is concluded that although localization of c...

  4. Ultrastructural maturation of human bone marrow mesenchymal stem cells-derived cardiomyocytes under alternative induction of 5-azacytidine.

    Science.gov (United States)

    Piryaei, Abbas; Soleimani, Masoud; Heidari, Mohammad Hassan; Saheli, Mona; Rohani, Razieh; Almasieh, Mohammadali

    2015-05-01

    Adult cardiomyocytes lack the ability to proliferate and are unable to repair damaged heart tissue, therefore differentiation of stem cells to cardiomyocytes represents an exceptional opportunity to study cardiomyocytes in vitro and potentially provides a valuable source for replacing damaged tissue. However, characteristic maturity of the in vitro differentiated cardiomyocytes and methods to achieve it are yet to be optimized. In this study, differentiation of human bone marrow-mesenchymal stem cells (hBM-MSCs) into cardiomyocytes is accomplished and the process investigated ultrastructurally. The hBM-MSCs were alternatively treated with 5 μM of 5-azacytidine (5-aza) for 8 weeks resulting in differentiation to cardiomyocytes. Expressions of cardiomyocyte-specific genes [cardiac α-actinin, cardiac β-myosin heavy chain (MHC) and connexin-43] and proteins (cardiac α-actinin, cardiac troponin and connexin-43) were confirmed in a time-dependent manner from the first to the fifth weeks post-induction. Ultrastructural maturation of hBM-MSCs-derived cardiomyocyte (MSCs-CM) corresponded with increase in number and organization of myofilaments in cells over time. Starting from week five, organized myofibrils along with developing sarcomeres were detectable. Later on, MSCs-CM were characterized by the presence of sarcoplasmic reticulum, T-tubules and diads as cardiomyocytes connected to each other by intercalated disc-like structures. Here, we showed the potential of hBM-MSCs as a source for the production of cardiomyocytes and confirmed mature ultrastructural characteristics of these cells using our alternative incubation method. PMID:25573851

  5. Micropipette aspiration on the outer hair cell lateral wall.

    OpenAIRE

    Sit, P S; Spector, A A; Lue, A J; Popel, A S; Brownell, W.E.

    1997-01-01

    The mechanical properties of the lateral wall of the guinea pig cochlear outer hair cell were studied using the micropipette aspiration technique. A fire-polished micropipette with an inner diameter of approximately 4 microm was brought into contact with the lateral wall and negative pressure was applied. The resulting deformation of the lateral wall was recorded on videotape and subjected to morphometric analysis. The relation between the length of the aspirated portion of the cell and aspir...

  6. Regulation of Meristem Morphogenesis by Cell Wall Synthases in Arabidopsis

    OpenAIRE

    Yang, Weibing; Schuster, Christoph; Beahan, Cherie T.; Charoensawan, Varodom; Peaucelle, Alexis; Bacic, Antony; Doblin, Monika S.; Wightman, Raymond; Meyerowitz, Elliot M.

    2016-01-01

    The cell walls of the shoot apical meristem (SAM), containing the stem cell niche that gives rise to the above-ground tissues, are crucially involved in regulating differentiation. It is currently unknown how these walls are built and refined or their role, if any, in influencing meristem developmental dynamics. We have combined polysaccharide linkage analysis, immuno-labeling, and transcriptome profiling of the SAM to provide a spatiotemporal plan of the walls of this dynamic structure. We f...

  7. Ultrastructural characterization (morphological and topochemical) of wood pulp fibres

    OpenAIRE

    Fernando, Dinesh

    2007-01-01

    Different electron microscopy techniques including SEM (scanning electron microscopy), FE-SEM (field emission-scanning electron microscopy), TEM (transmission electron microscopy) and Immuno-gold TEM (immuno-gold transmission electron microscopy) were applied in order to gain a better understanding of the influence of the native softwood fibre cell wall ultrastructure including morphology and topochemistry (i.e. lignin and glucomannan distribution) during mechanical pulping. In thermomechanic...

  8. Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

    International Nuclear Information System (INIS)

    The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B1 and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

  9. Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

    Science.gov (United States)

    Ribeiro, J.; Cavaglieri, L.; Vital, H.; Cristofolini, A.; Merkis, C.; Astoreca, A.; Orlando, J.; Carú, M.; Dalcero, A.; Rosa, C. A. R.

    2011-05-01

    The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B 1 and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

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

    Science.gov (United States)

    Cosgrove, D. J.

    1997-01-01

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

  11. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-17

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

  12. Hemicellulose biosynthesis and degradation in tobacco cell walls

    NARCIS (Netherlands)

    Compier, M.G.M.

    2005-01-01

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

  13. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.

    2012-01-01

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

  14. Ultrastructural alteration of the cell surface of Staphylococcus aureus cultured in a different salt condition

    Directory of Open Access Journals (Sweden)

    Kanemasa,Yasuhiro

    1974-10-01

    Full Text Available Staphylococcus aureus growing in a normal NaGI medium has a specific NaGI tolerance property to grow in the medium contain. ing NaGl in as high a concentration as over 10%. In our comparative study of the cells proliferating in the normal NaGI medium and 10% NaGl medium, we have observed the following differences aside from the changes of lipid composition in the cytoplasmic membrane previously reported. 1. S. aureus grown in high NaGl medium undergoes changes as to increase its size and reduce its surface area. 2. The thickness and weight of cell wall are increased to about 1. 7 times and 1. 32 times, respectively. 3. The protoplast prepared from S. aureus growing in the high NaGI medium shows a weaker resistance to hypotonic condition than that from normal cell.

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

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

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

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

    Science.gov (United States)

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

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  17. Ultrastructure of the extended ribonucleic acid molecules from purified ribosomes of Rous sarcoma virus-induced mouse ascites sarcoma cells

    Directory of Open Access Journals (Sweden)

    Yamamoto,Goki

    1974-04-01

    Full Text Available To clarify the ultrastructure of the extended ribosomal RNA molecules, electron microscopic observations were carried out on the RNA molecules extracted from purified ribosomes of mouse ascites sarcoma cells. By the treatment with ethylenediamine-tetraacetate agglomerated rRNA molecules were elongated to thread-like structure by partial unfolding. The lengths of thread-like molecules were measured as less than Iii. The strand of RNA molecules stained with uranyl acetate was observed approximately l5A in width.

  18. On-Off Switches for Secondary Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Huan-Zhong Wang; Richard A.Dixon

    2012-01-01

    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.

  19. The role of wall calcium in the extension of cell walls of soybean hypocotyls

    Science.gov (United States)

    Virk, S. S.; Cleland, R. E.

    1990-01-01

    Calcium crosslinks are load-bearing bonds in soybean (Glycine max (L.) Merr.) hypocotyl cell walls, but they are not the same load-bearing bonds that are broken during acid-mediated cell elongation. This conclusion is reached by studying the relationship between wall calcium, pH and the facilitated creep of frozen-thawed soybean hypocotyl sections. Supporting data include the following observations: 1) 2-[(2-bis-[carboxymethyl]amino-5-methylphenoxy)methyl]-6-methoxy-8-bis[car boxymethyl]aminoquinoline (Quin 2) and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) caused only limited facilitated creep as compared with acid, despite removal of comparable or larger amounts of wall calcium; 2) the pH-response curves for calcium removal and acid-facilitated creep were different; 3) reversible acid-extension occurred even after removal of almost all wall calcium with Quin 2; and 4) growth of abraded sections did not involve a proportional loss of wall calcium. Removal of wall calcium, however, increased the capacity of the walls to undergo acid-facilitated creep. These data indicate that breakage of calcium crosslinks is not a major mechanism of cell-wall loosening in soybean hypocotyl tissues.

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

    OpenAIRE

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

    2009-01-01

    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 play an important role in the defence mechanisms against plant pathogens and wounding. As constituents of plant cell walls and due to their anionic nature, pectic polysaccharides are considered to be ...

  1. Protection of ultrastructure in chilling-stressed banana leaves by salicylic acid

    Institute of Scientific and Technical Information of China (English)

    KANG Guo-zhang; WANG Zheng-xun; XIA Kuai-fei; SUN Gu-chou

    2007-01-01

    Objective: Chilling tolerance of salicylic acid (SA) in banana seedlings (Musa acuminata cv., Williams 8818) was investigated by changes in ultrastructure in this study. Methods: Light and electron microscope observation. Results: Pretreatment with 0.5 mmol/L SA under normal growth conditions (30/22 ℃) by foliar spray and root irrigation resulted in many changes in ultrastructure of banana cells, such as cells separation from palisade parenchymas, the appearance of crevices in cell walls, the swelling of grana and stromal thylakoids, and a reduction in the number of starch granules. These results implied that SA treatment at 30/22 ℃ could be a type of stress. During 3 d of exposure to 7 ℃ chilling stress under low light, however, cell ultrastructure of SA-pretreated banana seedlings showed less deterioration than those of control seedlings (distilled water-pretreated). Conclusion:SA could provide some protection for cell structure of chilling-stressed banana seedling.

  2. The state of cell wall pectin monitored by wall associated kinases: A model

    OpenAIRE

    Kohorn, Bruce D

    2015-01-01

    The Wall Associated Kinases (WAKs) bind to both cross-linked polymers of pectin in the plant cell wall, but have a higher affinity for smaller fragmented pectins that are generated upon pathogen attack or wounding. WAKs are required for cell expansion during normal seedling development and this involves pectin binding and a signal transduction pathway involving MPK3 and invertase induction. Alternatively WAKs bind pathogen generated pectin fragments to activate a distinct MPK6 dependent stres...

  3. Glucuronoarabinoxylan structure in the walls of Aechmea leaf chlorenchyma cells is related to wall strength.

    Science.gov (United States)

    Ceusters, Johan; Londers, Elsje; Brijs, Kristof; Delcour, Jan A; De Proft, Maurice P

    2008-09-01

    In CAM-plants rising levels of malic acid in the early morning cause elevated turgor pressures in leaf chlorenchyma cells. Under specific conditions this process is lethal for sensitive plants resulting in chlorenchyma cell burst while other species can cope with these high pressures and do not show cell burst under comparable conditions. The non-cellulosic polysaccharide composition of chlorenchyma cell walls was investigated and compared in three cultivars of Aechmea with high sensitivity for chlorenchyma cell burst and three cultivars with low sensitivity. Chlorenchyma layers were cut from the leaf and the non-cellulosic carbohydrate fraction of the cell wall fraction was analyzed by gas-liquid chromatography. Glucuronoarabinoxylans (GAXs) were the major non-cellulosic polysaccharides in Aechmea. The fine structure of these GAXs was strongly related to chlorenchyma wall strength. Chlorenchyma cell walls from cultivars with low sensitivity to cell burst were characterized by an A/X ratio of ca. 0.13 while those from cultivars with high sensitivity showed an A/X ratio of ca. 0.23. Xylose chains from cultivars with high cell burst sensitivity were ca. 40% more substituted with arabinose compared to cultivars with low sensitivity for cell burst. The results indicate a relationship in vivo between glucuronoarabinoxylan fine structure and chlorenchyma cell wall strength in Aechmea. The evidence obtained supports the hypothesis that GAXs with low degrees of substitution cross-link cellulose microfibrils, while GAXs with high degrees of substitution do not. A lower degree of arabinose substitution on the xylose backbone implies stronger cell walls and the possibility of withstanding higher internal turgor pressures without cell bursting. PMID:18632122

  4. How cell wall complexity influences saccharification efficiency in Miscanthus sinensis.

    Science.gov (United States)

    De Souza, Amanda P; Alvim Kamei, Claire L; Torres, Andres F; Pattathil, Sivakumar; Hahn, Michael G; Trindade, Luisa M; Buckeridge, Marcos S

    2015-07-01

    The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell walls are thought to display compositional differences that lead to emergence of a very high level of complexity, resulting in great diversity in cell wall architectures. In this work, a set of different techniques was used to access the complexity of cell walls of different genotypes of Miscanthus sinensis in order to understand how they interfere with saccharification efficiency. Three genotypes of M. sinensis displaying different patterns of correlation between lignin content and saccharification efficiency were subjected to cell wall analysis by quantitative/qualitative analytical techniques such as monosaccharide composition, oligosaccharide profiling, and glycome profiling. When saccharification efficiency was correlated negatively with lignin, the structural features of arabinoxylan and xyloglucan were found to contribute positively to hydrolysis. In the absence of such correlation, different types of pectins, and some mannans contributed to saccharification efficiency. Different genotypes of M. sinensis were shown to display distinct interactions among their cell wall components, which seem to influence cell wall hydrolysis. PMID:25908240

  5. Messenger Functions of the Bacterial Cell Wall-derived Muropeptides

    OpenAIRE

    Boudreau, Marc A.; Fisher, Jed F.; Mobashery, Shahriar

    2012-01-01

    Bacterial muropeptides are soluble peptidoglycan structures central to recycling of the bacterial cell wall, and messengers in diverse cell-signaling events. Bacteria sense muropeptides as signals that antibiotics targeting cell-wall biosynthesis are present, and eukaryotes detect muropeptides during the innate immune response to bacterial infection. This review summarizes the roles of bacterial muropeptides as messengers, with a special emphasis on bacterial muropeptide structures and the re...

  6. Ultrastructural study of sperm cells in Acanthocolpidae: the case of Stephanostomum murielae and Stephanostomoides tenuis (Digenea

    Directory of Open Access Journals (Sweden)

    Abdoulaye J.S. Bakhoum

    2015-02-01

    Full Text Available The mature spermatozoa of Stephanostomum murielae and Stephanostomoides tenuis are described by transmission electron microscopy. They present several ultrastructural features previously reported in other digeneans. Their spermatozoa possess two axonemes of different length showing the 9 + ‘1’ trepaxonematan pattern, four attachment zones, two mitochondria (with an anterior moniliform one in S. murielae, a nucleus, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The main differences between the mature spermatozoon of S. murielae and S. tenuis are the maximum number of cortical microtubules, the morphology of the anterior spermatozoon extremity and the anterior mitochondrion. This study is the first concerning members of the family Acanthocolpidae. The main ultrastructural characteristics discussed are the morphology of the anterior and posterior spermatozoon extremities, antero-lateral electron dense material, external ornamentations, spine-like bodies and number and morphology of mitochondria. In addition, the phylogenetic significance of all these ultrastructural features is discussed and compared to molecular results in order to highlight the complex relationships in the Digenea.

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

    Science.gov (United States)

    Balestrini, Raffaella; Bonfante, Paola

    2014-01-01

    Cell walls are deeply involved in the molecular talk between partners during plant and microbe interactions, and their role in mycorrhizae, i.e., the widespread symbiotic associations established between plant roots and soil fungi, has been investigated extensively. All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged. The exchange of molecules between the fungal and the plant cytoplasm takes place both through their plasma membranes and their cell walls; a functional compartment, known as the symbiotic interface, is thus defined. Among all the symbiotic interfaces, the complex intracellular interface of arbuscular mycorrhizal (AM) symbiosis has received a great deal of attention since its first description. Here, in fact, the host plasma membrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. By contrast, in ectomycorrhizae (ECM), where the fungus grows outside and between the root cells, plant and fungal cell walls are always in direct contact and form the interface between the two partners. The organization and composition of cell walls within the interface compartment is a topic that has attracted widespread attention, both in ecto- and endomycorrhizae. The aim of this review is to provide a general overview of the current knowledge on this topic by integrating morphological observations, which have illustrated cell wall features during mycorrhizal interactions, with the current data produced by genomic and transcriptomic approaches. PMID:24926297

  8. A proteomic and genetic analysis of the Neurospora crassa conidia cell wall proteins identifies two glycosyl hydrolases involved in cell wall remodeling.

    Science.gov (United States)

    Ao, Jie; Aldabbous, Mash'el; Notaro, Marysa J; Lojacono, Mark; Free, Stephen J

    2016-09-01

    A proteomic analysis of the conidial cell wall identified 35 cell wall proteins. A comparison with the proteome of the vegetative hyphae showed that 16 cell wall proteins were shared, and that these shared cell wall proteins were cell wall biosynthetic proteins or cell wall structural proteins. Deletion mutants for 34 of the genes were analyzed for phenotypes indicative of conidial cell wall defects. Mutants for two cell wall glycosyl hydrolases, the CGL-1 β-1,3-glucanase (NCU07523) and the NAG-1 exochitinase (NCU10852), were found to have a conidial separation phenotype. These two enzymes function in remodeling the cell wall between adjacent conidia to facilitate conidia formation and dissemination. Using promoter::RFP and promoter::GFP constructs, we demonstrated that the promoters for 15 of the conidia-specific cell wall genes, including cgl-1 and nag-1, provided for conidia-specific gene expression or for a significant increase in their expression during conidiation. PMID:27381444

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    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......Relax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is...

  10. Regulation of Meristem Morphogenesis by Cell Wall Synthases in Arabidopsis.

    Science.gov (United States)

    Yang, Weibing; Schuster, Christoph; Beahan, Cherie T; Charoensawan, Varodom; Peaucelle, Alexis; Bacic, Antony; Doblin, Monika S; Wightman, Raymond; Meyerowitz, Elliot M

    2016-06-01

    The cell walls of the shoot apical meristem (SAM), containing the stem cell niche that gives rise to the above-ground tissues, are crucially involved in regulating differentiation. It is currently unknown how these walls are built and refined or their role, if any, in influencing meristem developmental dynamics. We have combined polysaccharide linkage analysis, immuno-labeling, and transcriptome profiling of the SAM to provide a spatiotemporal plan of the walls of this dynamic structure. We find that meristematic cells express only a core subset of 152 genes encoding cell wall glycosyltransferases (GTs). Systemic localization of all these GT mRNAs by in situ hybridization reveals members with either enrichment in or specificity to apical subdomains such as emerging flower primordia, and a large class with high expression in dividing cells. The highly localized and coordinated expression of GTs in the SAM suggests distinct wall properties of meristematic cells and specific differences between newly forming walls and their mature descendants. Functional analysis demonstrates that a subset of CSLD genes is essential for proper meristem maintenance, confirming the key role of walls in developmental pathways. PMID:27212401

  11. Sperm-cell ultrastructure of North American sturgeons. IV. The pallid sturgeon (Scaphirhynchus albus Forbes and Richardson, 1905)

    Science.gov (United States)

    DiLauro, M.N.; Walsh, R.A.; Peiffer, M.; Bennett, R.M.

    2001-01-01

    Sperm-cell morphology and ultrastructure in the pallid sturgeon (Scaphirhynchus albus) were examined using transmission and scanning electron microscopy. Metrics and structure were compared with similar metrics obtained from other published descriptions of sturgeon sperm cells. General morphology was found to be similar to that of sperm cells of the white (Acipenser transmontanus), lake (A. fulvescens), stellate (A. stellatus), Chinese (A. sinensis), Russian (A. gueldenstaedti colchicus), and shortnose (A. brevirostrum) sturgeons, which all shared a gradual tapering of the nuclear diameter from posterior to anterior, unlike that of the Atlantic sturgeon (A. oxyrhynchus). The sperm cell of the pallid sturgeon was similar in size to that of the Atlantic sturgeon, being only slightly larger. The sperm cell of the pallid sturgeon differed from those of other sturgeons chiefly in the acrosomal region, where the posterolateral projections (PLP) have the shape of an acute triangle and are arranged in a spiral about the longitudinal axis of the cell. The PLP were longer than those of other sturgeons, being twice the length of those of the Atlantic sturgeon and 58% longer than those of the lake sturgeon. Also, in cross section the acrosome had the shape of a hollow cone rather than the cap of an oak tree acorn, as was found in ultrastructural studies of other sturgeons. In addition, we were able to confirm that the structural arrangement of the distal centriole of the midpiece is identical with that of the proximal centriole: nine sets of microtubular triplets around the periphery of the centriole. This information is of potential use to fishery biologists, forensic biologists, zoologists, reproductive physiologists, taxonomists, evolutionary biologists, and aquaculturists.

  12. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    Directory of Open Access Journals (Sweden)

    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  13. Echinococcus multilocularis Leuckart, 1863 (Taeniidae): new data on sperm ultrastructure.

    Science.gov (United States)

    Miquel, Jordi; Świderski, Zdzisław; Azzouz-Maache, Samira; Pétavy, Anne-Françoise

    2016-06-01

    The present study establishes the ultrastructural organisation of the mature spermatozoon of Echinococcus multilocularis, which is essential for future research on the location of specific proteins involved in the sperm development in this species and also in Echinococcus granulosus. Thus, the ultrastructural characteristics of the sperm cell are described by means of transmission electron microscopy. The spermatozoon of E. multilocularis is a filiform cell, which is tapered at both extremities and lacks mitochondria. It exhibits all the characteristics of type VII spermatozoon of tapeworms, namely a single axoneme, crested bodies, spiralled cortical microtubules and nucleus, a periaxonemal sheath and intracytoplasmic walls. Other characteristics observed in the male gamete are the presence of a >900-nm long apical cone in its anterior extremity and only the axoneme in its posterior extremity. The ultrastructural characters of the spermatozoon of E. multilocularis are compared with those of other cestodes studied to date, with particular emphasis on representatives of the genus Taenia. The most interesting finding concerns the presence of two helical crested bodies in E. multilocularis while in the studied species of Taenia, there is only one crested body. Future ultrastructural studies of other species of the genus Echinococcus would be of particular interest in order to confirm whether or not the presence of two crested bodies is a characteristic of this genus. PMID:26960958

  14. Modification of cell wall polysaccharides during retting of cassava roots.

    Science.gov (United States)

    Ngolong Ngea, Guillaume Legrand; Guillon, Fabienne; Essia Ngang, Jean Justin; Bonnin, Estelle; Bouchet, Brigitte; Saulnier, Luc

    2016-12-15

    Retting is an important step in traditional cassava processing that involves tissue softening of the roots to transform the cassava into flour and various food products. The tissue softening that occurs during retting was attributed to the degradation of cell wall pectins through the action of pectin-methylesterase and pectate-lyase that possibly originated from a microbial source or the cassava plant itself. Changes in cell wall composition were investigated during retting using chemical analysis, specific glycanase degradation and immuno-labelling of cell wall polysaccharides. Pectic 1,4-β-d-galactan was the main cell wall polysaccharide affected during the retting of cassava roots. This result suggested that better control of pectic galactan degradation and a better understanding of the degradation mechanism by endogenous endo-galactanase and/or exogenous microbial enzymes might contribute to improve the texture properties of cassava products. PMID:27451197

  15. Roles of tRNA in cell wall biosynthesis

    DEFF Research Database (Denmark)

    Dare, Kiley; Ibba, Michael

    2012-01-01

    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...... specificity of this diverse enzymatic family is necessary to aid current efforts in designing potential bactericidal agents. These two enzyme families are linked only by the substrate with which they modify the cell wall, aa-tRNA; their structure, cell wall modification processes and the physiological changes...... responsible for cell wall modifications, aminoacyl-phosphatidylglycerol synthases (aaPGSs) and Fem, were discovered some time ago, they have recently become of intense interest for their roles in the antimicrobial resistance of pathogenic microorganisms. The addition of positively charged amino acids to...

  16. Ultrastructure of Single Cells, Callus-like and Monosore-like Cells in Porphyra yezoensis Ueda on Semi solid Culture Medium

    Institute of Scientific and Technical Information of China (English)

    梅俊学; 沈颂东; 姜明; 费修绠

    2003-01-01

    It had been demonstrated that individual cells or protoplasts isolated from Porphyra thallus by enzyme could develop into normal leafy thalli in the same way as monospores, and that isolated cells develop in different way in liquid and on semi solid media. The authors observed the ultrastructure of isolated vegetative cells cultured on semi solid media and compared them with those of monospores and isolated cells cultured in liquid media. The results showed that subcellular structures were quite different among cells in different conditions. In their development, isolated cells on semi solid media did not show the characteristic subcellular feature of monospore formation, such as production of fibrous vesicles. Callus like cells formed on semi solid media underwent a distinctive modification in cellular organization. They developed characteristic cell inclusions and a special 2 layer cell covering. Golgi bodies, ER, starch grains, mitochondria. Vacuoles were not commonly found in them.

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

    Directory of Open Access Journals (Sweden)

    Lima D.U.

    2001-01-01

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

  18. Transformation of Abdominal Wall Endometriosis to Clear Cell Carcinoma

    OpenAIRE

    Maria Paula Ruiz; Darryl Lewis Wallace; Matthew Thomas Connell

    2015-01-01

    Clear cell carcinoma is the least common of the malignant transformations reported in nonpelvic sites of endometriosis. Two cases with clear cell carcinoma transformation arising from endometriosis in abdominal wall scars are presented. These patients underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy, pelvic washings, and abdominal wall lesion resection. The first case had initial treatment with chemotherapy, while chemotherapy and radiation therapy were given for th...

  19. Analyzing the complex machinery of cell wall biosynthesis

    OpenAIRE

    Timmers, J.F.P.

    2009-01-01

    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 highly interesting target of scientific research. In this thesis a protein-protein interaction strategy was used to gain insight in the cell wall biosynthesis of Arabidopsis thaliana and to identif...

  20. Biosynthetic origin of mycobacterial cell wall arabinosyl residues.

    OpenAIRE

    Scherman, M.; Weston, A; Duncan, K; Whittington, A; Upton, R; Deng, L.; Comber, R; Friedrich, J D; McNeil, M

    1995-01-01

    Designing new drugs that inhibit the biosynthesis of the D-arabinan moiety of the mycobacterial cell wall arabinogalactan is one important basic approach for treatment of mycobacterial diseases. However, the biosynthetic origin of the D-arabinosyl monosaccharide residues themselves is not known. To obtain information on this issue, mycobacteria growing in culture were fed glucose labeled with 14C or 3H in specific positions. The resulting radiolabeled cell walls were isolated and hydrolyzed, ...

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

    NARCIS (Netherlands)

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

    2009-01-01

    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

  2. Ultrastructure of oval cells in children with chronic hepatitis B, with special emphasis on the stage of liver fibrosis: The first pediatric study

    Institute of Scientific and Technical Information of China (English)

    Maria Elzbieta Sobaniec-Lotowska; Joanna Maria Lotowska; Dariusz Marek Lebensztejn

    2007-01-01

    AIM: To investigate the ultrastructure of oval ceils in children with chronic hepatitis B, with special emphasis on their location in areas of collagen fibroplasia.METHODS: Morphological investigations were conducted on biopsy material obtained from 40 children,aged 3-16 years with chronic hepatitis B. The stage of fibrosis was assessed histologically using the arbitrary semiquantitative numerical scoring system proposed by Ishak et al. The material for ultrastructural investigation was fixed in glutaraldehyde and paraformaldehyde and processed for transmission-electron microscopic analysis.RESULTS: Ultrastructural examination of biopsy specimens obtained from children with chronic hepatitis B showed the presence of two types of oval cells, the hepatic progenitor cells and intermediate hepatic-like cells. These cells were present in the parenchyma and were seen most commonly in areas of intense periportal fibrosis (at least stage 2 according to Ishak et al) and in the vicinity of the limiting plate of the lobule. The activated nonparenchymal hepatic cells, i.e. transformed hepatic stellate cells and Kupffer cells were seen in close proximity to the intermediate hepatic-like cells.CONCLUSION: We found a distinct relationship between the prevalence of oval cells (hepatic progenitor cells and intermediate hepatocyte-like cells) and fibrosis stage in pediatric patients with chronic hepatitis B.

  3. Ultrastructural and histological changes induced by ivermectin in the ovary of Argas persicus after feeding

    OpenAIRE

    Hamdy, H.Swelim; Aleya, S.Marzouk;Ashraf,A.M.Montasser

    2003-01-01

    The ovarian wall of A.persicus consists of primary oocytes of three developmental stages namely , young , previtellogenic and vitellogenic in addition to interstitial cells . After feeding and mating , the three stages and interstitial cells , particularly funicle cells that carry oocytes , markedly increased in size and their cytoplasmic organelles exhibit notable changes correlated with yolk and egg shell formation . The present study examined the hitological and ultrastructural aspects dur...

  4. Bacterial glycobiology: rhamnose-containing cell wall polysaccharides in Gram-positive bacteria.

    OpenAIRE

    Mistou, Michel-Yves; Sutcliffe, Iain; van Sorge, Nina

    2016-01-01

    The composition of the Gram-positive cell wall is typically described as containing peptidoglycan, proteins and essential secondary cell wall structures called teichoic acids, which comprise approximately half of the cell wall mass. The cell walls of many species within the genera Streptococcus, Enterococcus and Lactococcus contain large amounts of the sugar rhamnose, which is incorporated in cell wall-anchored polysaccharides (CWP) that possibly function as homologues of well-studied wall te...

  5. Bioacumulation and ultrastructural effects of Cd, Cu, Pb and Zn in the moss Scorpiurum circinatum (Brid.) Fleisch. and Loeske

    International Nuclear Information System (INIS)

    This paper tested if culturing the moss Scorpiurum circinatum (Brid.) Fleisch. and Loeske with metal solutions (Cd, Cu, Pb and Zn) for 30 days causes metal bioaccumulation and ultrastructural changes. The results showed that despite the high heavy metal concentrations in treatment solutions, treated samples did not show severe ultrastructural changes and cells were still alive and generally well preserved. Bioaccumulation highlighted that moss cells survived to heavy metal toxicity by immobilizing most toxic ions extracellularly, likely in binding sites of the cell wall, which is the main site of metal detoxification. - Highlights: ► Ultrastructural effects of metal ions on moss cells are not severe. ► Plastids are the main target of heavy metal pollution. ► Moss cells survive to metal toxicity by immobilizing most toxic ions extracellularly. - Moss cells survive to heavy metal toxicity by immobilizing most toxic ions extracellularly.

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

    Directory of Open Access Journals (Sweden)

    Canut Hervé

    2006-05-01

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

  7. From Dynamic Live Cell Imaging to 3D Ultrastructure: Novel Integrated Methods for High Pressure Freezing and Correlative Light-Electron Microscopy.

    OpenAIRE

    Spiegelhalter, Coralie; Tosch, Valérie; Hentsch, Didier; Koch, Marc; Kessler, Pascal; Schwab, Yannick; Laporte, Jocelyn

    2010-01-01

    BACKGROUND: In cell biology, the study of proteins and organelles requires the combination of different imaging approaches, from live recordings with light microscopy (LM) to electron microscopy (EM). METHODOLOGY: To correlate dynamic events in adherent cells with both ultrastructural and 3D information, we developed a method for cultured cells that combines confocal time-lapse images of GFP-tagged proteins with electron microscopy. With laser micro-patterned culture substrate, we created coo...

  8. DCB-adapted plant cells possess unique wall structure

    Energy Technology Data Exchange (ETDEWEB)

    Shedletzky, E.; Shmuel, M. (Hebrew Univ., Jerusalem (Israel)); Delmer, D. (Hebrew Univ., Jerusalem (Israel) Michigan State Univ., East Lansing (USA)); Lamport, D. (Michigan State Univ., East Lansing (USA))

    1990-05-01

    Suspension-cultured cells of tomato (Lycopersicon esculentum VF 36) haven been adapted to growth on high concentrations of 2,6-dichloro-benzonitrile (DCB), an herbicide which inhibits cellulose biosynthesis. The mechanism of adaptation appears to rest largely on the ability of thee cells to divide and expand in the virtual absence of a cellulose-xyloglucan network. Walls of adapted cells growing on DCB also differ from non-adapted cells by having reduced levels of hydroxyproline in protein, both in bound and salt-elutable form, and in having a much higher proportion of homogalacturonon and rhamnogalacturonan-like polymers. Most of these latter polymers are apparently cross-linked in the wall via phenolic-esters and/or phenolic ether linkages, and these polymers appear to represent the major load-bearing network in thee unusual cell walls. The surprising finding that plant cells can survive in the virtual absence of a major load-bearing network in their primary cell walls indicates that plants possess remarkable flexibility for tolerating changes in wall composition.

  9. 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.

  10. Active caspase-3 and ultrastructural evidence of apoptosis in spontaneous and induced cell death in bovine in vitro produced pre-implantation embryos

    DEFF Research Database (Denmark)

    Gjørret, Jakob O.; Fabian, Dusan; Avery, Birthe;

    2007-01-01

    In this study we investigated chronological onset and involvement of active caspase-3, apoptotic nuclear morphology, and TUNEL-labeling, as well as ultrastructural evidence of apoptosis, in both spontaneous and induced cell death during pre-implantation development of bovine in vitro produced...... staining for detection of apoptotic nuclear morphology, and subjected to fluorescence microscopy. Additionally, treated and untreated blastocysts were fixed and processed for ultrastructural identification of apoptosis. Untreated embryos revealed no apoptotic features at 2- and 4-cell stages. However......, active caspase-3 and apoptotic nuclear morphology were observed in an untreated 8-cell stage, and TUNEL-labeling was observed from the 16-cell stage. Blastomeres concurrently displaying all apoptotic features were present in a few embryos at 16-cell and morula stages and in all blastocysts. All three...

  11. Cell wall proteomics of the green alga Haematococcus pluvialis (Chlorophyceae).

    Science.gov (United States)

    Wang, Sheng-Bing; Hu, Qiang; Sommerfeld, Milton; Chen, Feng

    2004-03-01

    The green microalga Haematococcus pluvialis can synthesize and accumulate large amounts of the ketocarotenoid astaxanthin, and undergo profound changes in cell wall composition and architecture during the cell cycle and in response to environmental stresses. In this study, cell wall proteins (CWPs) of H. pluvialis were systematically analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with peptide mass fingerprinting (PMF) and sequence-database analysis. In total, 163 protein bands were analyzed, which resulted in positive identification of 81 protein orthologues. The highly complex and dynamic composition of CWPs is manifested by the fact that the majority of identified CWPs are differentially expressed at specific stages of the cell cycle along with a number of common wall-associated 'housekeeping' proteins. The detection of cellulose synthase orthologue in the vegetative cells suggested that the biosynthesis of cellulose occurred during primary wall formation, in contrast to earlier observations that cellulose was exclusively present in the secondary wall of the organism. A transient accumulation of a putative cytokinin oxidase at the early stage of encystment pointed to a possible role in cytokinin degradation while facilitating secondary wall formation and/or assisting in cell expansion. This work represents the first attempt to use a proteomic approach to investigate CWPs of microalgae. The reference protein map constructed and the specific protein markers obtained from this study provide a framework for future characterization of the expression and physiological functions of the proteins involved in the biogenesis and modifications in the cell wall of Haematococcus and related organisms. PMID:14997492

  12. Inhibitors targeting on cell wall biosynthesis pathway of MRSA.

    Science.gov (United States)

    Hao, Haihong; Cheng, Guyue; Dai, Menghong; Wu, Qinghua; Yuan, Zonghui

    2012-11-01

    Methicillin resistant Staphylococcus aureus (MRSA), widely known as a type of new superbug, has aroused world-wide concern. Cell wall biosynthesis pathway is an old but good target for the development of antibacterial agents. Peptidoglycan and wall teichoic acids (WTAs) biosynthesis are two main processes of the cell wall biosynthesis pathway (CWBP). Other than penicillin-binding proteins (PBPs), some key factors (Mur enzymes, lipid I or II precursor, etc.) in CWBP are becoming attractive molecule targets for the discovery of anti-MRSA compounds. A number of new compounds, with higher affinity for PBPs or with inhibitory activity on such molecule targets in CWBP of MRSA, have been in the pipeline recently. This review concludes recent research achievements and provides a complete picture of CWBP of MRSA, including the peptidoglycan and wall teichoic acids synthesis pathway. The potential inhibitors targeting on CWBP are subsequently presented to improve development of novel therapeutic strategies for MRSA. PMID:22898792

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

    OpenAIRE

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

    2015-01-01

    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...

  14. Co-delivery of cell-wall-forming enzymes in the same vesicle for coordinated fungal cell wall formation.

    Science.gov (United States)

    Schuster, Martin; Martin-Urdiroz, Magdalena; Higuchi, Yujiro; Hacker, Christian; Kilaru, Sreedhar; Gurr, Sarah J; Steinberg, Gero

    2016-01-01

    Fungal cells are surrounded by an extracellular cell wall. This complex matrix of proteins and polysaccharides protects against adverse stresses and determines the shape of fungal cells. The polysaccharides of the fungal wall include 1,3-β-glucan and chitin, which are synthesized by membrane-bound synthases at the growing cell tip. A hallmark of filamentous fungi is the class V chitin synthase, which carries a myosin-motor domain. In the corn smut fungus Ustilago maydis, the myosin-chitin synthase Mcs1 moves to the plasma membrane in secretory vesicles, being delivered by kinesin-1 and myosin-5. The myosin domain of Mcs1 enhances polar secretion by tethering vesicles at the site of exocytosis. It remains elusive, however, how other cell-wall-forming enzymes are delivered and how their activity is coordinated post secretion. Here, we show that the U. maydis class VII chitin synthase and 1,3-β-glucan synthase travel in Mcs1-containing vesicles, and that their apical secretion depends on Mcs1. Once in the plasma membrane, anchorage requires enzyme activity, which suggests co-synthesis of chitin and 1,3-β-glucan polysaccharides at sites of exocytosis. Thus, delivery of cell-wall-forming enzymes in Mcs1 vesicles ensures local foci of fungal cell wall formation. PMID:27563844

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    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.

  16. Simulated microgravity inhibits cell wall regeneration of Penicillium decumbens protoplasts

    Science.gov (United States)

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

    2010-09-01

    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.

  17. How cell wall complexity influences saccharification efficiency in Miscanthus sinensis

    NARCIS (Netherlands)

    Souza, De Amanda P.; Lessa Alvim Kamei, Claire; Torres Salvador, Andres Francisco; Pattathil, Sivakumar; Hahn, Michael G.; Trindade, Luisa M.; Buckeridge, Marcos S.

    2015-01-01

    The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell wal

  18. Alterations in auxin homeostasis suppress defects in cell wall function.

    Directory of Open Access Journals (Sweden)

    Blaire J Steinwand

    Full Text Available The plant cell wall is a highly dynamic structure that changes in response to both environmental and developmental cues. It plays important roles throughout plant growth and development in determining the orientation and extent of cell expansion, providing structural support and acting as a barrier to pathogens. Despite the importance of the cell wall, the signaling pathways regulating its function are not well understood. Two partially redundant leucine-rich-repeat receptor-like kinases (LRR-RLKs, FEI1 and FEI2, regulate cell wall function in Arabidopsis thaliana roots; disruption of the FEIs results in short, swollen roots as a result of decreased cellulose synthesis. We screened for suppressors of this swollen root phenotype and identified two mutations in the putative mitochondrial pyruvate dehydrogenase E1α homolog, IAA-Alanine Resistant 4 (IAR4. Mutations in IAR4 were shown previously to disrupt auxin homeostasis and lead to reduced auxin function. We show that mutations in IAR4 suppress a subset of the fei1 fei2 phenotypes. Consistent with the hypothesis that the suppression of fei1 fei2 by iar4 is the result of reduced auxin function, disruption of the WEI8 and TAR2 genes, which decreases auxin biosynthesis, also suppresses fei1 fei2. In addition, iar4 suppresses the root swelling and accumulation of ectopic lignin phenotypes of other cell wall mutants, including procuste and cobra. Further, iar4 mutants display decreased sensitivity to the cellulose biosynthesis inhibitor isoxaben. These results establish a role for IAR4 in the regulation of cell wall function and provide evidence of crosstalk between the cell wall and auxin during cell expansion in the root.

  19. Changes of lipid domains in Bacillus subtilis cells with disrupted cell wall peptidoglycan

    OpenAIRE

    Muchová, Katarína; Wilkinson, Anthony J.; Barák, Imrich

    2011-01-01

    The cell wall is responsible for cell integrity and the maintenance of cell shape in bacteria. The Gram-positive bacterial cell wall consists of a thick peptidoglycan layer located on the outside of the cytoplasmic membrane. Bacterial cell membranes, like eukaryotic cell membranes, are known to contain domains of specific lipid and protein composition. Recently, using the membrane-binding fluorescent dye FM4-64, helix-like lipid structures extending along the long axis of the cell and consist...

  20. The Interplay between Cell Wall Mechanical Properties and the Cell Cycle in Staphylococcus aureus

    OpenAIRE

    Bailey, Richard G.; Turner, Robert D.; Mullin, Nic; Clarke, Nigel,; Foster, Simon J.; Hobbs, Jamie K.

    2014-01-01

    The nanoscale mechanical properties of live Staphylococcus aureus cells during different phases of growth were studied by atomic force microscopy. Indentation to different depths provided access to both local cell wall mechanical properties and whole-cell properties, including a component related to cell turgor pressure. Local cell wall properties were found to change in a characteristic manner throughout the division cycle. Splitting of the cell into two daughter cells followed a local softe...

  1. Structure, function, and biosynthesis of plant cell walls: proceedings of the seventh annual symposium in botany

    Energy Technology Data Exchange (ETDEWEB)

    Dugger, W.M.; Bartnicki-Garcia, S. (eds.)

    1984-01-01

    Papers in the following areas were included in these symposium proceedings: (1) cell wall chemistry and biosynthesis; (2) cell wall hydrolysis and associated physiology; (3) cellular events associated with cell wall biosynthesis; and (4) interactions of plant cell walls with pathogens and related responses. Papers have been individually abstracted for the data base. (ACR)

  2. Ultrastructural Analysis of Nanogold-Labeled Cell Surface Microvilli in Liquid by Atmospheric Scanning Electron Microscopy and Their Relevance in Cell Adhesion

    Directory of Open Access Journals (Sweden)

    Mitsuo Suga

    2013-10-01

    Full Text Available The adhesion of leukocytes circulating in the blood to vascular endothelium is critical for their trafficking in the vasculature, and CD44 is an important cell surface receptor for rolling adhesion. In this study, we demonstrate the correlative observation of CD44 distribution at the lymphocyte cell surface in liquid by fluorescence optical microscopy and immuno-electron microscopy using an atmospheric scanning electron microscope (ASEM. The ultrastructure of the cell surface was clearly imaged by ASEM using positively charged Nanogold particles. ASEM analysis demonstrated microvilli projections around the cell surface and the localization of CD44 on the microvilli. Treatment of cells with cytochalasin D resulted in a loss of the microvilli projections and concomitantly abrogated CD44-mediated adhesion to its ligand hyaluronan. These results suggest the functional relevance of microvilli in CD44-mediated rolling adhesion under shear flow.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    analysed showed calcofluor-stained appositions. However, in habituated and dehabituated cells, appositions were not recognized by an anticallose antibody. This finding suggested the accumulation of an extracellular polysaccharide different to callose, probably a 1,4-ß-glucan in these cell lines......The effects of the cellulose inhibitor dichlobenil on the cell wall composition and structure during the habituation/dehabituation process of suspension-cultured bean cells were assessed. A range of techniques were used including cell wall fractionation, sugar analysis, immunofluorescence and...... fluorochrome labelling of resin-embedded sections, and immunodot assays (IDAs) of cell wall fractions. The cell walls from bean cell suspensions with initial levels of habituation to dichlobenil had decreased levels of cellulose, but this effect lessened with increasing numbers of subcultures. All cell walls...

  4. 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

    2009-01-01

    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 (http://aranet.mpimp-golm.mpg.de/corecarb) containing downloadable files for all the transcriptional associations.

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

    Directory of Open Access Journals (Sweden)

    Gabriel Paës

    2014-07-01

    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.

  6. Synthesis and Application of Plant Cell Wall Oligogalactans

    DEFF Research Database (Denmark)

    Andersen, Mathias Christian Franch

    The plant cell walls represent almost 50% of the biomass found in plants and are therefore one of the main targets for biotechnological research. Major motivators are their potential as a renewable energy source for transport fuels, as functional foods, and as a source of raw materials to generate...... chemical building blocks for industrial processes. To achieve a sustainable development it is necessary to optimize plant production and utilization. This will require a better understanding of the cell wall structure and function at the molecular level. The cell wall is composed by an intricate network of...... as part of the arabinogalactans series. The fragments were applied in the characterization of a glycosyl transferase, a hydrolase and to study the important cancer biomarker galectin-3. The work done during an external stay at University of Oxford is also presented. This concerns isolation and...

  7. The role of the cell wall in plant immunity

    DEFF Research Database (Denmark)

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

    2014-01-01

    The battle between plants and microbes is evolutionarily ancient, highly complex, and often co-dependent. A primary challenge for microbes is to breach the physical barrier of host cell walls whilst avoiding detection by the plant's immune receptors. While some receptors sense conserved microbial...... features, others monitor physical changes caused by an infection attempt. Detection of microbes leads to activation of appropriate defense responses that then challenge the attack. Plant cell walls are formidable and dynamic barriers. They are constructed primarily of complex carbohydrates joined by...... numerous distinct connection types, and are subject to extensive post-synthetic modification to suit prevailing local requirements. Multiple changes can be triggered in cell walls in response to microbial attack. Some of these are well described, but many remain obscure. The study of the myriad of subtle...

  8. Cell wall integrity signalling in human pathogenic fungi.

    Science.gov (United States)

    Dichtl, Karl; Samantaray, Sweta; Wagener, Johannes

    2016-09-01

    Fungi are surrounded by a rigid structure, the fungal cell wall. Its plasticity and composition depend on active regulation of the underlying biosynthesis and restructuring processes. This involves specialised signalling pathways that control gene expression and activities of biosynthetic enzymes. The cell wall integrity (CWI) pathway is the central signalling cascade required for the adaptation to a wide spectrum of cell wall perturbing conditions, including heat, oxidative stress and antifungals. In the recent years, great efforts were made to analyse the CWI pathway of diverse fungi. It turned out that the CWI signalling cascade is mostly conserved in the fungal kingdom. In this review, we summarise as well as compare the current knowledge on the canonical CWI pathway in the human pathogenic fungi Candida albicans, Candida glabrata, Aspergillus fumigatus and Cryptococcus neoformans. Understanding the differences and similarities in the stress responses of these organisms could become a key to improving existing or developing new antifungal therapies. PMID:27155139

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

    International Nuclear Information System (INIS)

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

  10. Stem and progenitor cells in biostructure of blood vessel walls

    Directory of Open Access Journals (Sweden)

    Krzysztof Korta

    2013-09-01

    Full Text Available Development of vascular and hematopoietic systems during organogenesis occurs at the same time. During vasculogenesis, a small part of cells does not undergo complete differentiation but stays on this level, “anchored” in tissue structures described as stem cell niches. The presence of blood vessels within tissue stem cell niches is typical and led to identification of niches and ensures that they are functioning. The three-layer biostructure of vessel walls for artery and vein, tunica: intima, media and adventitia, for a long time was defined as a mechanical barrier between vessel light and the local tissue environment. Recent findings from vascular biology studies indicate that vessel walls are dynamic biostructures, which are equipped with stem and progenitor cells, described as vascular wall-resident stem cells/progenitor cells (VW-SC/PC. Distinct zones for vessel wall harbor heterogeneous subpopulations of VW-SC/PC, which are described as “subendothelial or vasculogenic zones”. Recent evidence from in vitro and in vivo studies show that prenatal activity of stem and progenitor cells is not only limited to organogenesis but also exists in postnatal life, where it is responsible for vessel wall homeostasis, remodeling and regeneration. It is believed that VW-SC/PC could be engaged in progression of vascular disorders and development of neointima. We would like to summarize current knowledge about mesenchymal and progenitor stem cell phenotype with special attention to distribution and biological properties of VW-SC/PC in biostructures of intima, media and adventitia niches. It is postulated that in the near future, niches for VW-SC/PC could be a good source of stem and progenitor cells, especially in the context of vessel tissue bioengineering as a new alternative to traditional revascularization therapies.

  11. Evolution of the cell wall components during terrestrialization

    Directory of Open Access Journals (Sweden)

    Alicja Banasiak

    2014-12-01

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

  12. Bacterial Cell Wall-Induced Arthritis: Chemical Composition and Tissue Distribution of Four Lactobacillus Strains

    OpenAIRE

    Šimelyte, Egle; Rimpiläinen, Marja; Lehtonen, Leena; Zhang, Xiang; Toivanen, Paavo

    2000-01-01

    To study what determines the arthritogenicity of bacterial cell walls, cell wall-induced arthritis in the rat was applied, using four strains of Lactobacillus. Three of the strains used proved to induce chronic arthritis in the rat; all were Lactobacillus casei. The cell wall of Lactobacillus fermentum did not induce chronic arthritis. All arthritogenic bacterial cell walls had the same peptidoglycan structure, whereas that of L. fermentum was different. Likewise, all arthritogenic cell walls...

  13. Particle Trajectories in Rotating Wall Cell Culture Devices

    Science.gov (United States)

    Ramachandran N.; Downey, J. P.

    1999-01-01

    Cell cultures are extremely important to the medical community since such cultures provide an opportunity to perform research on human tissue without the concerns inherent in experiments on individual humans. Development of cells in cultures has been found to be greatly influenced by the conditions of the culture. Much work has focused on the effect of the motions of cells in the culture relative to the solution. Recently rotating wall vessels have been used with success in achieving improved cellular cultures. Speculation and limited research have focused on the low shear environment and the ability of rotating vessels to keep cells suspended in solution rather than floating or sedimenting as the primary reasons for the improved cellular cultures using these devices. It is widely believed that the cultures obtained using a rotating wall vessel simulates to some degree the effect of microgravity on cultures. It has also been speculated that the microgravity environment may provide the ideal acceleration environment for culturing of cellular tissues due to the nearly negligible levels of sedimentation and shear possible. This work predicts particle trajectories of cells in rotating wall vessels of cylindrical and annular design consistent with the estimated properties of typical cellular cultures. Estimates of the shear encountered by cells in solution and the interactions with walls are studied. Comparisons of potential experiments in ground and microgravity environments are performed.

  14. Cell Wall Polysaccharides of Candida albicans Induce Mast Cell Degranulation in the Gut

    OpenAIRE

    Sakurai, Atsuko; Yamaguchi, Natsu; Sonoyama, Kei

    2012-01-01

    We investigated Candida albicans-induced mast cell degranulation in vitro and in vivo. Cell wall fraction but not culture supernatant and cell membrane fraction prepared from hyphally grown C. albicans induced β-hexosaminidase release in RBL-2H3 cells. Cell wall mannan and soluble β-glucan fractions also induced β-hexosaminidase release. Histological examination of mouse forestomach showed that C. albicans gut colonization induces mast cell degranulation. However, intragastric administration ...

  15. Phagocytic properties of lung alveolar wall cells

    Directory of Open Access Journals (Sweden)

    Tanaka,Akisuke

    1974-04-01

    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.

  16. A new nidovirus (NamDinh virus NDiV): Its ultrastructural characterization in the C6/36 mosquito cell line

    International Nuclear Information System (INIS)

    We describe the ultrastructure of the NamDinh virus (NDiV), a new member of the order Nidovirales grown in the C6/36 mosquito cell line. Uninfected and NDiV-infected cells were investigated by electron microscopy 24–48 h after infection. The results show that the viral nucleocapsid-like particles form clusters concentrated in the vacuoles, the endoplasmic reticulum, and are scattered in the cytoplasm. Mature virions of NDiV were released as budding particles on the cell surface where viral components appear to lie beneath and along the plasma membrane. Free homogeneous virus particles were obtained by ultracentrifugation on sucrose gradients of culture fluids. The size of the round-shaped particles with a complete internal structure was 80 nm in diameter. This is the first study to provide information on the morphogenesis and ultrastructure of the first insect nidovirus NDiV, a missing evolutionary link in the emergence of the viruses with the largest RNA genomes. - Highlights: • NamDinh virus (NDiV), a new member of the order Nidovirales was tested in cultured cell line. • The morphogenesis and ultrastructure of NDiV were investigated by electron microscopy. • The viral nucleocapsid-like particles clustered and scattered in the cytoplasm. • NDiVs were released as budding particles on the cell surface. • The size of the viral particles with a complete internal structure was 80 nm in diameter

  17. A new nidovirus (NamDinh virus NDiV): Its ultrastructural characterization in the C6/36 mosquito cell line

    Energy Technology Data Exchange (ETDEWEB)

    Thuy, Nguyen Thanh, E-mail: ngtthuy02@yahoo.com [National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hai Ba Trung District, Hanoi (Viet Nam); Huy, Tran Quang, E-mail: huytq@nihe.org.vn [National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hai Ba Trung District, Hanoi (Viet Nam); Nga, Phan Thi [National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hai Ba Trung District, Hanoi (Viet Nam); Morita, Kouichi [Department of Virology, Institute of Tropical Medicine, Global COE Program, Nagasaki University, Nagasaki (Japan); Dunia, Irene; Benedetti, Lucio [Institut Jacques Monod, UMR7592 Université Paris Diderot/CNRS, Paris (France)

    2013-09-15

    We describe the ultrastructure of the NamDinh virus (NDiV), a new member of the order Nidovirales grown in the C6/36 mosquito cell line. Uninfected and NDiV-infected cells were investigated by electron microscopy 24–48 h after infection. The results show that the viral nucleocapsid-like particles form clusters concentrated in the vacuoles, the endoplasmic reticulum, and are scattered in the cytoplasm. Mature virions of NDiV were released as budding particles on the cell surface where viral components appear to lie beneath and along the plasma membrane. Free homogeneous virus particles were obtained by ultracentrifugation on sucrose gradients of culture fluids. The size of the round-shaped particles with a complete internal structure was 80 nm in diameter. This is the first study to provide information on the morphogenesis and ultrastructure of the first insect nidovirus NDiV, a missing evolutionary link in the emergence of the viruses with the largest RNA genomes. - Highlights: • NamDinh virus (NDiV), a new member of the order Nidovirales was tested in cultured cell line. • The morphogenesis and ultrastructure of NDiV were investigated by electron microscopy. • The viral nucleocapsid-like particles clustered and scattered in the cytoplasm. • NDiVs were released as budding particles on the cell surface. • The size of the viral particles with a complete internal structure was 80 nm in diameter.

  18. Reorganization of the endosomal system in Salmonella-infected cells: the ultrastructure of Salmonella-induced tubular compartments.

    Directory of Open Access Journals (Sweden)

    Viktoria Krieger

    2014-09-01

    Full Text Available During the intracellular life of Salmonella enterica, a unique membrane-bound compartment termed Salmonella-containing vacuole, or SCV, is formed. By means of translocated effector proteins, intracellular Salmonella also induce the formation of extensive, highly dynamic membrane tubules termed Salmonella-induced filaments or SIF. Here we report the first detailed ultrastructural analyses of the SCV and SIF by electron microscopy (EM, EM tomography and live cell correlative light and electron microscopy (CLEM. We found that a subset of SIF is composed of double membranes that enclose portions of host cell cytosol and cytoskeletal filaments within its inner lumen. Despite some morphological similarities, we found that the formation of SIF double membranes is independent from autophagy and requires the function of the effector proteins SseF and SseG. The lumen of SIF network is accessible to various types of endocytosed material and our CLEM analysis of double membrane SIF demonstrated that fluid phase markers accumulate only between the inner and outer membrane of these structures, a space continual with endosomal lumen. Our work reveals how manipulation of the endosomal membrane system by an intracellular pathogen results in a unique tubular membrane compartmentalization of the host cell, generating a shielded niche permissive for intracellular proliferation of Salmonella.

  19. EffectS Of Synergism Between PVY and PVX on Vi rus Titer and Cell Ultrastructure in Tobacco Plants

    Institute of Scientific and Technical Information of China (English)

    LI Han; GUO Xing-qi; LI Xiang-dong; GUO Heng-jun; LI Zhao-hui

    2003-01-01

    The viruses titer and the ultrastructure of infected cells in tobacco host (Nicotiana tabacum cv.Samsun), which doubly infected with potato virus Y necrosis strain (PVYN) and potato virus X (PVX), were studied under greenhouse conditions. The results indicated that PVYN and PVX interacted synergistically, and tobacco plants which doubly infected with PVX and PVYN could greatly increase symptom severity as compared with that induced by the single virus. As determined by triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA), the titer of PVX in the tobacco leaves infected with both PVYN and PVX was up to 9.10 times higher than the plants infected with PVX only. No significant differences in PVYN titer were detected between singly and doubly infected plants. The enhancement of PVX titer in doubly infected plants was evident in greenhouse and was independent of the virus strains, tested seasons, intervals between PVYN and PVX inoculation. When sections of doubly infected leaves were examined with an electron microscope, it could be frequently found that cells contained pinwheels and large masses of PVX-like particles, pinwheels and laminate inclusions, or all three structures, most of them were swollen, and their chloroplast and other organella were destructed heavily. This suggested that doubly infected cells were involved in the enhancement phenomenon,which seemed to be the result of an increase in the amount of PVX synthesized in them.

  20. Distribution and ultrastructure of pigment cells in the skins of normal and albino adult turbot, Scophthalmus Maximus

    Institute of Scientific and Technical Information of China (English)

    GUO Huarong; HUANG Bing; QI Fei; ZHANG Shicui

    2007-01-01

    The distribution and ultrastructure of pigment cells in skins of normal and albino adult turbots were examined with transmission electron microscopy (TEM). Three types of pigment cells of melanophore, iridophore and xanthophore have been recognized in adult turbot skins. The skin color depends mainly on the amount and distribution of melanophore and iridophore, as xanthophore is quite rare. No pigment cells can be found in the epidermis of the skins. In the pigmented ocular skin of the turbot, melanophore and iridophore are usually co-localized in the dermis. This is quite different from the distribution in larvae skin. In albino and white blind skins of adult turbots, however, only iridophore monolayer still exists, while the melanophore monolayer disappears. This cytological evidence explains why the albino adult turbot, unlike its larvae, could never resume its body color no matter what environmental and nutritional conditions were provided. Endocytosis is quite active in the cellular membrane of the iridophore. This might be related to the formation of reflective platelet and stability of the iridophore.

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

    International Nuclear Information System (INIS)

    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. The Cellulose System in the Cell Wall of Micrasterias

    Science.gov (United States)

    Kim; Herth; Vuong; Chanzy

    1996-11-01

    The cellulose system of the cell wall of Micrasterias denticulata and Micrasterias rotata was analyzed by diffraction contrast transmission electron microscopy, electron diffraction, and X-ray analysis. The studies, achieved on disencrusted cell ghosts, confirmed that the cellulose microfibrils occurred in crisscrossed bands consisting of a number of parallel ribbon-like microfibrils. The individual microfibrils had thicknesses of 5 nm for a width of around 20 nm, but in some instances, two or three microfibrils merged into one another to yield larger monocrystalline domains reaching up to 60 nm in lateral size. The orientation of the cellulose of Micrasterias is very unusual, as it was found that in the cell wall, the equatorial crystallographic planes of cellulose having a d-spacing of 0.60 nm [(11;0) in the Ibeta cellulose unit cell defined by Sugiyama et al., 1991, Macromolecules 24, 4168-4175] were oriented perpendicular to the cell wall surface. Up to now, such orientation has been found only in Spirogyra, another member of the Zygnemataceae group. The unusual structure of the secondary wall cellulose of Micrasterias may be tentatively correlated with the unique organization of the terminal complexes, which in this alga occur as hexagonal arrays of rosettes. PMID:8986649

  3. The metabolic enzyme ManA reveals a link between cell wall integrity and chromosome morphology.

    OpenAIRE

    Maya Elbaz; Sigal Ben-Yehuda

    2010-01-01

    Author Summary The bacterial cell is resistant to extremes of osmotic pressure and protected against mechanical damages by the existence of a rigid outer shell defined as the cell wall. The strength of the cell wall is achieved by the presence of long glycan strands cross-linked by peptide side bridges. The cell wall is a dynamic structure continuously being synthesized and modified to allow for cell growth and division. Damaging the cell wall leads to abnormal cellular morphologies and cell ...

  4. A model of cell wall expansion based on thermodynamics of polymer networks

    Science.gov (United States)

    Veytsman, B. A.; Cosgrove, D. J.

    1998-01-01

    A theory of cell wall extension is proposed. It is shown that macroscopic properties of cell walls can be explained through the microscopic properties of interpenetrating networks of cellulose and hemicellulose. The qualitative conclusions of the theory agree with the existing experimental data. The dependence of the cell wall yield threshold on the secretion of the wall components is discussed.

  5. Heat stress causes alterations in the cell-wall polymers and anatomy of coffee leaves (Coffea arabica L.).

    Science.gov (United States)

    Lima, Rogério Barbosa; dos Santos, Tiago Benedito; Vieira, Luiz Gonzaga Esteves; Ferrarese, Maria de Lourdes Lúcio; Ferrarese-Filho, Osvaldo; Donatti, Lucélia; Boeger, Maria Regina Torres; Petkowicz, Carmen Lúcia de Oliveira

    2013-03-01

    Coffee plants were subjected to heat stress (37 °C) and compared with control plants (24 °C). Cell wall polysaccharides were extracted using water (W), EDTA (E) and 4M NaOH (H30 and H70). In addition, monolignols were analyzed, and the leaves were observed by microscopy. Plants under heat stress accumulated higher contents of arabinose and galactose in fraction W. Xylose contents were observed to decrease in H30 fractions after the heat stress, whereas galactose and uronic acid increased. H70 fractions from plants exposed to heat stress showed increased xylose contents, whereas the contents of arabinose and glucose decreased. Differences in the molar-mass profiles of polysaccharides were also observed. The primary monolignol contents increased after the heat stress. Structural alterations in palisade cells and ultrastructural damage in chloroplasts were also observed. Our results demonstrate that the chemical profile of coffee cell-wall polymers and structural cell anatomy change under heat stress. PMID:23465912

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. [Ultrastructural analysis of anastomosis group 9 of Rhizoctonia solani].

    Science.gov (United States)

    Cedeño, L; Palacios Prü, E

    1996-01-01

    The ultrastructure of R. solani AG-9 (S-21, ATCC 62804) was investigated with transmission electron microscopy (TEM). The most important characteristics were those related with cell wall thickness, cytoplasmic matrix composition, number of nuclei and nucleoli and secretory material production. The majority of examined hyphae showed lateral cell walls thinner than those recorded before. The cytoplasmic matrix consistently appeared differentiated into two classes, one formed by a highly electron dense granular fine material and the other one showing a coloidal substance of very low density which give these cells a 'tiger-like' aspect. The grannular dense matrix always had abundant free ribosomes and usually surrounded the cytoplasmic organelles and the septal pore apparatus. The somatic cells showed up to 5 nuclei, some of which with three nucleoli. Masses of secretory material surrounded by membrane were regularly seen in the cytoplasm, with sizes similar to those of nuclei. PMID:9334448

  8. Ultrastructural analysis of anastomosis group 9 of Rhizoctonia solani

    International Nuclear Information System (INIS)

    The ultrastructure of R. solani AG-9 (S-21, ATCC 62804) was investigated with transmission electron microscopy (TEM). The most important characteristics were those related with cell wall thickness, cytoplasmic matrix composition, number of nuclei and nucleoli and secretory material production. The majority of examined hyphae showed lateral cell walls thinner than those recorded before. The cytoplasmic matrix consistently appeared differentiated into two classes, one formed by a highly electron dense granular fine material and the other one showing a coloidal substance of very low density which give these cells a 'tiger-like' aspect. The granular dense matrix always had abundant free ribosomes and usually surrounded the cytoplasmic organelles and the septal pore apparatus. The somatic cells showed up to 5 nuclei, some of which with three nucleoli. Masses of secretory material surrounded by membrane were regularly seen in the cytoplasm, with sizes similar to those of nuclei

  9. Characterization of uterine granular cell tumors in B6C3F1 mice: a histomorphologic, immunohistochemical, and ultrastructural study.

    Science.gov (United States)

    Veit, A C; Painter, J T; Miller, R A; Hardisty, J F; Dixon, D

    2008-09-01

    The granular cell tumor is most often a benign neoplasm of uncertain origin. Four uterine granular cell tumors in control and treated female B6C3F1 mice were identified in chronic studies at the National Toxicology Program. Two tumors occurred in untreated control animals and 2 in treated animals receiving different compounds. Tissue sections were evaluated histologically and stained with hematoxylin and eosin, periodic acid-Schiff with diastase resistance, Masson's trichrome, toluidine blue, phosphotungstic acid-hematoxylin, and stained immunohistochemically with a panel of antibodies to muscle (desmin, alpha smooth muscle actin), neural (S-100, neuron specific enolase), epithelial (wide-spectrum cytokeratin), and macrophage (F4/80) markers. The main histomorphologic feature of tumor cells was the presence of abundant cytoplasmic eosinophilic granules that stained positive for periodic acid-Schiff with diastase resistance. Tumors varied in appearance and were comprised of sheets and nests of round to polygonal cells with distinct borders. Nuclei were hyperchromatic, pleomorphic, and centrally to eccentrically located and often contained single nucleoli. Occasional multinucleated giant cells were observed. Tumors were pale pink and homogeneous with trichrome stain and negative with toluidine blue. Three tumors had positive to weakly positive immunoreactivity for desmin, and 1 was positive for alpha smooth muscle actin. Expression of S-100, wide-spectrum cytokeratin, and neuron-specific enolase was negative for all tumors. Ultrastructurally, prominent electron-dense cytoplasmic granules were abundant and contained secondary lysosomes with heterogeneous lysosomal contents. The characteristics of these uterine granular cell tumors were suggestive of a myogenic origin. PMID:18725470

  10. Catalysts of plant cell wall loosening [version 1; referees: 2 approved

    OpenAIRE

    Cosgrove, Daniel J.

    2016-01-01

    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...

  11. An emerging role of pectic rhamnogalacturonanII for cell wall integrity

    OpenAIRE

    Reboul, Rebecca; Tenhaken, Raimund

    2012-01-01

    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 pre...

  12. Cell wall structure and function in lactic acid bacteria.

    Science.gov (United States)

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2014-08-29

    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. PMID:25186919

  13. A new type of 3-D peripheral ultrastructure in Glaucocystis (Glaucocystales, Glaucophyta) as revealed by ultra-high voltage electron microscopy.

    Science.gov (United States)

    Takahashi, Toshiyuki; Nishida, Tomoki; Saito, Chieko; Yasuda, Hidehiro; Nozaki, Hisayoshi

    2016-06-01

    The coccoid glaucophyte genus Glaucocystis is characterized by having a thick cell wall, which has to date prohibited examination of the native ultrastructural features of the protoplast periphery. Recently, however, the three-dimensional (3-D) ultrastructure of the protoplast periphery was revealed in two divergent Glaucocystis species, with the world's most powerful ultra-high voltage electron microscope (UHVEM). The two species exhibit morphological diversity in terms of their 3-D ultrastructural features. However, these two types do not seem to encompass actual ultrastructural diversity in the genetically diverse genus Glaucocystis. Here, we report a new type of peripheral 3-D ultrastructure resolved in "G. incrassata" SAG 229-2 cells by 3-D modeling based on UHVEM tomography using high-pressure freezing and freeze-substitution fixation. The plasma membrane and underlying flattened vesicles in "G. incrassata" SAG 229-2 exhibited grooves at intervals of 200-600 nm, and the flattened vesicles often overlapped one another at the protoplast periphery. This 3-D ultrastructure differs from those of the two types previously reported in other species of Glaucocystis. The possibility of classification of Glaucocystis species based on the 3-D ultrastructure of the protoplast periphery is discussed. PMID:27273537

  14. Analyzing the complex machinery of cell wall biosynthesis

    NARCIS (Netherlands)

    Timmers, J.F.P.

    2009-01-01

    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

  15. The identification of cell wall degrading enzymes in Globodera rostochiensis

    NARCIS (Netherlands)

    Popeijus, H.E.

    2002-01-01

    This thesis describes the identification of cell wall degrading enzymes of the potato cyst nematode Globodera rostochiensis . A robust method using expressed sequence tags (ESTs) was applied to identify new parasitism related enzymes. One of the ESTs revealed the first pectate lyase from a metazoan

  16. Magnetic domain wall conduits for single cell applications

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

    Hilz, H.

    2007-01-01

    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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    OpenAIRE

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

    2003-01-01

    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.

  20. Hetero-oligomeric cell wall channels (porins) of Nocardia farcinica.

    Science.gov (United States)

    Kläckta, Christian; Knörzer, Philipp; Riess, Franziska; Benz, Roland

    2011-06-01

    The cell wall of Nocardia farcinica contains a cation-selective cell wall channel, which may be responsible for the limited permeability of the cell wall of N. farcinica for negatively charged antibiotics. Based on partial sequencing of the protein responsible for channel formation derived from N. farcinica ATTC 3318 we were able to identify the corresponding genes (nfa15890 and nfa15900) within the known genome of N. farcinica IFM 10152. The corresponding genes of N. farcinica ATTC 3318 were separately expressed in the Escherichia coli BL21DE3Omp8 strain and the N-terminal His10-tagged proteins were purified to homogeneity using immobilized metal affinity chromatography. The pure proteins were designated NfpANHis and NfpBNHis, for N. farcinica porin A and N. farcinica porin B. The two proteins were checked separately for channel formation in lipid bilayers. Our results clearly indicate that the proteins NfpANHis and NfpBNHis expressed in E. coli could only together form a channel in lipid bilayer membranes. This means that the cell wall channel of N. farcinica is formed by a heterooligomer. NfpA and NfpB form together a channel that may structurally be related to MspA of Mycobacterium smegmatis based on amino acid comparison and renaturation procedure. PMID:21092733

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

    Czech Academy of Sciences Publication Activity Database

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

    2013-01-01

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

  2. Polymer mobility in cell walls of cucumber hypocotyls

    Science.gov (United States)

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

    1999-01-01

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

  3. Environmental stability of stem cell wall traits in alfalfa

    Science.gov (United States)

    The concentration of stem cell wall constituents in alfalfa, Medicago sativa L., herbage can affect dry matter intake and energy availability in dairy and beef production systems and impact energy conversion efficiency when alfalfa is used to produce biofuels. Stem Klason lignin, glucose, xylose, an...

  4. Plant Cell Wall Carbohydrates as Substrates for Azospirillum brasiliense†

    OpenAIRE

    Myers, Mary L.; Hubbell, David H.

    1987-01-01

    Carbohydrate components (simple sugars and polysaccharides) of cell walls of pearl millet (Pennisetum americanum L., cv. Gahi) were studied as potential substrates for the root-associated diazotroph Azospirillum brasiliense Sp. 7. Simple sugars were utilized, but no evidence was obtained to support the suggestion that the polysaccharide components tested might serve as substrates for growth following hydrolysis by the associated azospirilla.

  5. Effects of zinc on the ultrastructure of the brain cells of the larvae of Clupea harengus L

    Energy Technology Data Exchange (ETDEWEB)

    Somasundaram, B.; King, P.E.; Shackley, S.E.

    1984-11-01

    C. harengus adults, which were about to spawn, were gill netted from Castle Reach, Wales, during March 1983. Eggs were stripped from these fish and artificially fertilized. The ultrastructural changes in the brain cells of C. harengus larvae, hatched from eggs incubated in four zinc concentrations (0.5, 2.0, 6.0 and 12.0 ppm), were examined by morphometric analysis. The fine structure of the brain cell was affected by zinc at all concentrations examined. Significant swelling of the nuclear membranes, rough endoplasmic reticulum, an increase in intracellular spaces and a decrease in the relative volume of mitochondria were observed. At 12.0 ppm zinc significant reduction in the relative volume of the nucleus, degeneration of the mitochondrial cristae and a reduction in the ribosomes were observed. In the zinc-treated larvae the reduced oxygen utilization by the mitochondria, accompanied by a possible loss of energy, would affect the normal function of the mid and hind brain, which would result in an impairment of visual and swimming responses. The effects of zinc, at concentrations which are not immediately lethal, are of importance to movement and hence to viability of the larvae. 26 references, 7 figures, 1 table.

  6. Distribution and ultrastructure of interstitial cells of Cajal in the mouse colon, using antibodies to Kit and Kit(W-lacZ) mice

    DEFF Research Database (Denmark)

    Vanderwinden, J M; Rumessen, J J; Bernex, F;

    2000-01-01

    place of the first exon of the Kit gene. In the subserosa, the interstitial cells of Cajal formed a two-dimensional plexus. In the myenteric area, the interstitial cells of Cajal formed a dense plexus that gradually merged with the interstitial cells of Cajal in the outer half of the circular muscle...... kinase receptor Kit as a marker. Sections and whole mounts were studied by confocal microscopy after double immunofluorescence with specific antibodies. The ultrastructure of Kit-expressing cells was examined by electron microcopy in KitW-lacz/+ transgenic mice, which carry the lacz gene inserted in...

  7. Cell wall structure and function in lactic acid bacteria

    OpenAIRE

    Kulakauskas, Saulius

    2014-01-01

    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 traditionall...

  8. A Phosphorylated Pseudokinase Complex Controls Cell Wall Synthesis in Mycobacteria

    OpenAIRE

    Gee, Christine L.; Papavinasasundaram, Kadamba G.; Blair, Sloane R.; Baer, Christina E.; Falick, Arnold M.; King, David S.; Griffin, Jennifer E.; Venghatakrishnan, Harene; Zukauskas, Andrew; Wei, Jun-Rong; Dhiman, Rakesh K.; Crick, Dean C.; Rubin, Eric J.; Sassetti, Christopher M.; Alber, Tom

    2012-01-01

    Prokaryotic cell wall biosynthesis is coordinated with cell growth and division, but the mechanisms regulating this dynamic process remain obscure. Here, we describe a phosphorylation-dependent regulatory complex that controls peptidoglycan (PG) biosynthesis in Mycobacterium tuberculosis. We found that PknB, a PG-responsive Ser-Thr protein kinase (STPK), initiates complex assembly by phosphorylating a kinase-like domain in the essential PG biosynthetic protein, MviN. This domain was structura...

  9. Molecular Mechanisms for Vascular Development and Secondary Cell Wall Formation

    OpenAIRE

    Yang, Jung Hyun; Wang, Huanzhong

    2016-01-01

    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 bio...

  10. Ultrastructure of cells after reversible dark-induced blocking of mitotic divisions in antheridial filaments of Chara vulgaris L.

    Directory of Open Access Journals (Sweden)

    Maria Kwiatkowska

    2014-02-01

    Full Text Available As compared with the control plants cultured under photoperiodic L : D = =14 : 10 conditions (K w i a t k o w s k a, M a s z e w s k i, 1978, the ultrastructure of nuclei -in cells blocked by a 5 day exposure to continuous darkness is characterized by homogenous arrangement. This homogeneity is maintained in all generations of antheridial filaments irrespective of cell length, which in the controls, being directly correlated with particular type of nuclear structure, may serve as a precise indicator of a given stage of interphase. From similarities in both the spatial distribution and content of condensed chromatin in is concluded that the block of the cell cycle is imposed at the beginning of the G2 phase. On comparing these cells with the early G2 period (stage VII in the control plants, marked changes in the structure of nucleoli were found. They decrease in size by half owing to the complete decline of granular component. The area occupied by endoplasmic reticulum undergoes a 50% reduction. The decrease in the activity of Golgi apparatus expressed by a drop in number of smooth vesicles surrounding a single dictyosome is found to parallel the limited rate of cell growth. The number of coated vesicles and cisterns of dictyosome slightly increases. Mitochondria show typical condensed configuration with dense matrices and swollen cristae, while in the control orthodox forms are prevailing. The mean size of mitochondria is smaller, but their number exceeds that of the control plants. The surface area of mitochondrial profiles is found to remain constant proportion of the cytoplasm section, e.g., about 3%. Dark-cultured antheridial filaments show absolute decline of lipid droplets. No differences were found in structure of plastids and vacuols, as well as in number of ribosomes in cytoplasm surface unit.

  11. From dynamic live cell imaging to 3D ultrastructure: novel integrated methods for high pressure freezing and correlative light-electron microscopy.

    Directory of Open Access Journals (Sweden)

    Coralie Spiegelhalter

    Full Text Available BACKGROUND: In cell biology, the study of proteins and organelles requires the combination of different imaging approaches, from live recordings with light microscopy (LM to electron microscopy (EM. METHODOLOGY: To correlate dynamic events in adherent cells with both ultrastructural and 3D information, we developed a method for cultured cells that combines confocal time-lapse images of GFP-tagged proteins with electron microscopy. With laser micro-patterned culture substrate, we created coordinates that were conserved at every step of the sample preparation and visualization processes. Specifically designed for cryo-fixation, this method allowed a fast freezing of dynamic events within seconds and their ultrastructural characterization. We provide examples of the dynamic oligomerization of GFP-tagged myotubularin (MTM1 phosphoinositides phosphatase induced by osmotic stress, and of the ultrastructure of membrane tubules dependent on amphiphysin 2 (BIN1 expression. CONCLUSION: Accessible and versatile, we show that this approach is efficient to routinely correlate functional and dynamic LM with high resolution morphology by EM, with immuno-EM labeling, with 3D reconstruction using serial immuno-EM or tomography, and with scanning-EM.

  12. Immunocytochemical and ultrastructural characterization of mammosomatotrope-, growth hormone-, and prolactin-cells from the gilthead sea bream (Sparus aurata l., Teleostei): an ontogenic study.

    Science.gov (United States)

    Villaplana, Mariano; García Ayala, Alfonsa; García Hernández, Maria Pilar; Agulleiro, Blanca

    2003-03-01

    Growth hormone (GH), prolactin (PRL), and mammosomatotrope (MS) cells of gilthead sea bream, Sparus aurata, a teleost fish, were studied in specimens from hatching to 15 months (adults) using conventional electron microscopy and an immunogold method using anti-tilapia GH sera and anti-chum salmon PRL serum. MS cells, immunoreactive to both anti-GH sera and anti-PRL sera, had been first identified in fish in a previous study in newly hatched larvae and in older larvae and juvenile specimens of Sparus aurata by light microscopic immunocytochemistry. In the present work, MS cells reacted positively to immunogold label only in older larvae and juveniles and their secretory granules immunoreacted with both GH and PRL antisera or with only one of them. MS cells were ultrastructurally similar to the PRL cells, with which they coincided in time. This is the first report on the ultrastructural characterization of MS cells in fish. In adults, the secretory granules of GH cells (immunoreactive to anti-GH serum) were mainly round, of variable size, and had a homogeneous, highly electron-dense content. Irregularly shaped secretory granules were also present. PRL cells (immunoreactive to anti-PRL serum) were usually observed in a follicular arrangement; they showed few, small, and mainly round secretory granules with a homogeneous and high or medium electron-dense content. Some oval or elongated secretory granules were also observed. GH and PRL cells that showed involutive features were also found. In newly hatched larvae, GH, PRL, and MS cells could not be distinguished either by their ultrastructure or by the immunogold labeling of the secretory granules. In 1-day-old larvae, presumptive GH and PRL cells were observed according to their position in the pituitary gland. In 2-day-old larvae, a few cells showed some of the ultrastructural features described for GH and PRL cells of adults. During development, the number, size, and shape of the secretory granules in both cell types

  13. Quantification of endocrine cells and ultrastructural study of insulin granules in the large intestine of opossum Didelphis aurita (Wied-Neuwied, 1826).

    Science.gov (United States)

    dos Santos, Daiane Cristina Marques; Cupertino, Marli do Carmo; Fialho, Maria do Carmo Queiroz; Barbosa, Alfredo Jose Afonso; Fonseca, Cláudio Cesar; Sartori, Sirlene Souza Rodrigues; da Matta, Sérgio Luis Pinto

    2014-02-01

    This study aimed to investigate the distribution of argyrophil, argentaffin, and insulin-immunoreactive endocrine cells in the large intestine of opossums (Didelphis aurita) and to describe the ultrastructure of the secretory granules of insulin-immunoreactive endocrine cells. Fragments of the large intestine of 10 male specimens of D. aurita were collected, processed, and subjected to staining, immunohistochemistry, and transmission electron microscopy. The argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells were sparsely distributed in the intestinal glands of the mucous layer, among other cell types of the epithelium in all regions studied. Proportionally, the argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells represented 62.75%, 36.26%, and 0.99% of the total determined endocrine cells of the large intestine, respectively. Quantitatively, there was no difference between the argyrophil and the argentaffin endocrine cells, whereas insulin-immunoreactive endocrine cells were less numerous. The insulin-immunoreactive endocrine cells were elongated or pyramidal, with rounded nuclei of irregularly contoured, and large amounts of secretory granules distributed throughout the cytoplasm. The granules have different sizes and electron densities and are classified as immature and mature, with the mature granules in predominant form in the overall granular population. In general, the granule is shown with an external electron-lucent halo and electron-dense core. The ultrastructure pattern in the granules of the insulin-immunoreactive endocrine cells was similar to that of the B cells of pancreatic islets in rats. PMID:24359801

  14. Crushing Strength of Aluminum Honeycomb with Thinning Cell Wall

    Science.gov (United States)

    Ogasawara, Nagahisa; Chiba, Norimasa; Kobayashi, Eiji; Kikuchi, Yuji

    To evaluate the crash safety of automobiles, various collision tests are performed by the auto industry. In the offset frontal collision test and the side collision test, the target is an aluminum honeycomb material which has thinning cell walls. In this study, based on the analyses of the shock absorption mechanism, a new crushing strength formula is proposed. First, load-displacement curves obtained from compression tests in quasi-static condition showed an almost linear relation between a thinning rate of cell walls and a crushing strength. Second, based on Wierzbicki's theory, a new formula was proposed, which can estimate a crushing strength of a honeycomb material with thinning wall. In addition, a correcting equation which considered an elastic deformation was also proposed. Third, parametric analyses were carried out with a FE model which can simulate a delamination between cell walls. The results obtained from the theory and FEM almost corresponded to each other for a wide range of the thinning rate. Fourth, impact tests were carried out, in which the weight was dropped freely at the speed used for the automobile tests. Those results almost agreed well with the sum of the theoretical crush strength and the inside air pressure.

  15. Nucleated assembly of Chlamydomonas and Volvox cell walls.

    Science.gov (United States)

    Adair, W S; Steinmetz, S A; Mattson, D M; Goodenough, U W; Heuser, J E

    1987-11-01

    The Chlamydomonas reinhardtii cell wall is made up of hydroxyproline-rich glycoproteins, arranged in five distinct layers. The W6 (crystalline) layer contains three major glycoproteins (GP1, GP2, GP3), selectively extractable with chaotropic agents, that self-assemble into crystals in vitro. A system to study W6 assembly in a quantitative fashion was developed that employs perchlorate-extracted Chlamydomonas cells as nucleating agents. Wall reconstitution by biotinylated W6 monomers was monitored by FITC-streptavidin fluorescence and quick-freeze/deep-etch electron microscopy. Optimal reconstitution was obtained at monomer concentrations (0.2-0.3 mg/ml) well below those required for nonnucleated assembly. Assembly occurred from multiple nucleation sites, and faithfully reflected the structure of the intact W6 layer. Specificity of nucleated assembly was demonstrated using two cell-wall mutants (cw-2 and cw-15); neither served as a substrate for assembly of wild-type monomers. In addition, W6 sublayers were assembled from purified components: GP2 and GP3 coassembled to form the inner (W6A) sublayer; this then served as a substrate for self-assembly of GP1 into the outer (W6B) sublayer. Finally, evolutionary relationships between C. reinhardtii and two additional members of the Volvocales (Chlamydomonas eugametos and Volvox carteri) were explored by performing interspecific reconstitutions. Hybrid walls were obtained between C. reinhardtii and Volvox but not with C. eugametos, confirming taxonomic assignments based on structural criteria. PMID:3680387

  16. Ultrastructural analysis of primary human urethral epithelial cell cultures infected with Neisseria gonorrhoeae.

    Science.gov (United States)

    Harvey, H A; Ketterer, M R; Preston, A; Lubaroff, D; Williams, R; Apicella, M A

    1997-06-01

    In men with gonococcal urethritis, the urethral epithelial cell is a site of infection. To study the pathogenesis of gonorrhea in this cell type, we have developed a method to culture primary human urethral epithelial cells obtained at the time of urologic surgery. Fluorescent analysis demonstrated that 100% of the cells stained for keratin. Microscopic analyses indicated that these epithelial cells arrayed in a pattern similar to that seen in urethral epithelium. Using immunoelectron and confocal microscopy, we compared the infection process seen in primary cells with events occurring during natural infection of the same cell type in men with gonococcal urethritis. Immunoelectron microscopy studies of cells infected with Neisseria gonorrhoeae 1291 Opa+ P+ showed adherence of organisms to the epithelial cell membrane, pedestal formation with evidence of intimate association between the gonococcal and the epithelial cell membranes, and intracellular gonococci present in vacuoles. Confocal studies of primary urethral epithelial cells showed actin polymerization upon infection. Polyclonal antibodies to the asialoglycoprotein receptor (ASGP-R) demonstrated the presence of this receptor on infected cells in the primary urethral cell culture. In situ hybridization using a fluorescent-labeled probe specific to the ASGP-R mRNA demonstrated this message in uninfected and infected cells. These features were identical to those seen in urethral epithelial cells in exudates from males with gonorrhea. Infection of primary urethral cells in culture mimics events seen in natural infection and will allow detailed molecular analysis of gonococcal pathogenesis in a human epithelial cell which is commonly infected. PMID:9169783

  17. 黄瓜黑星病菌致病机理的研究Ⅲ细胞壁降解酶和毒素对寄主超微结构的影响及其协同作用%PATHOGENIC MECHANISM OF SCAB OF CUCUMBER CAUSED BY Cladosporium cucumerinum Ⅲ EFFECTS AND SYNERGISM OF CELL WALL-DEGRADING ENZYMES ANDTOXIN PRODUCED BY C. cucumerinum ON ULTRASTRUCTURE OF CUCUMBER

    Institute of Scientific and Technical Information of China (English)

    李宝聚; 周长力; 赵奎华; 李凤云; 黄国坤

    2001-01-01

    本文通过透射电镜和扫描电镜观察,初步明确了果胶酶、纤维素酶及毒素对黄瓜叶组织超微结构的影响。在致病过程中,3种致病因子起着各自独立又相互联系的作用。3种致病因子对寄主超微结构的影响中,纤维素酶分解细胞壁能力最强,毒素对细胞质膜的作用最大,3种致病因子均可造成质壁分离,液泡、内质网受损。而叶绿体的被膜、片层结构主要被纤维素酶降解,线粒体的被膜主要被果胶酶降解,3种致病因子均能使叶绿体、线粒体内部空泡化。在分解叶表皮的过程中,所研究的3种致病因子首先是果胶酶降解果胶层,然后是纤维素酶、果胶酶、毒素对栅栏组织的分解,最后是纤维素酶、毒素作用于薄壁细胞壁,毒素、纤维素酶、果胶酶协同作用于细胞内部组织。%The effects of the cellulase, pectinase and toxin produced by Cladosporium cucumerinum on the leaf cell of cucumber were studied by TEM and SEM. The results indicated that the three pathogenic factors played independent and symplastic roles. The cellulase and pectinase played leading roles respectively in decomposition of cell wall and plasma membrane. The three factors could all result in plasmolysis and damage vacuoles and endoplasmic reticulum. Chloroplast envelope and lamellae structure were mainly digested by cellulase, whiles, mitochondrion envelope was chiefly digested by the pectinase. Each of the three factors could cause vacuolation in chloroplast and mitochondria. During the process of breach up the structure of epidermis of leaf, the cellulase acted on reticulate region, then the pectinase dissolved pectic layer.Following this, palisade tissue was damaged by the cellulase, pectinase and toxin. Finally,parenchyma was destroyed by cellulase and toxin,successively.

  18. In situ microscopic observation of chitin and fungal cells with chitinous cell walls in hydrothermal conditions

    OpenAIRE

    Shigeru Deguchi; Kaoru Tsujii; Koki Horikoshi

    2015-01-01

    Recent findings of intact chitin in fossil records suggest surprisingly high recalcitrance of this biopolymer during hydrothermal treatments. We also know in the experience of everyday life that mushroom, cells of which have chitinous cell walls, do not fall apart however long they are simmered. We used in situ optical microscopy to examine chitin and fungal cells with chitinous cell walls during hydrothermal treatments, and obtained direct evidence that they remained undegraded at temperatur...

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

    OpenAIRE

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

    2015-01-01

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

  20. Ultrastructural study of Kupffer cells in teleost liver under normal and experimental conditions.

    Science.gov (United States)

    Ferri, S; Sesso, A

    1981-01-01

    The Kupffer cells in the liver of the teleost fish, Pimelodus maculatus, are attached by desmosomes to the endothelial cells lining the sinusoids. These provide a strong attachment allowing them to resist the passage of blood. Following perfusion with India ink, both endothelial and Kupffer cells ingest India ink particles by pinocytosis and micropinocytosis. It is suggested that both cell types may represent two different functional states of the same cell. PMID:7296637

  1. The influenza fingerprints: NS1 and M1 proteins contribute to specific host cell ultrastructure signatures upon infection by different influenza A viruses

    International Nuclear Information System (INIS)

    Influenza A are nuclear replicating viruses which hijack host machineries in order to achieve optimal infection. Numerous functional virus–host interactions have now been characterized, but little information has been gathered concerning their link to the virally induced remodeling of the host cellular architecture. In this study, we infected cells with several human and avian influenza viruses and we have analyzed their ultrastructural modifications by using electron and confocal microscopy. We discovered that infections lead to a major and systematic disruption of nucleoli and the formation of a large number of diverse viral structures showing specificity that depended on the subtype origin and genomic composition of viruses. We identified NS1 and M1 proteins as the main actors in the remodeling of the host ultra-structure and our results suggest that each influenza A virus strain could be associated with a specific cellular fingerprint, possibly correlated to the functional properties of their viral components.

  2. The influenza fingerprints: NS1 and M1 proteins contribute to specific host cell ultrastructure signatures upon infection by different influenza A viruses

    Energy Technology Data Exchange (ETDEWEB)

    Terrier, Olivier; Moules, Vincent; Carron, Coralie; Cartet, Gaeelle [Equipe VirCell, Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Frobert, Emilie [Laboratoire de Virologie, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, 59 boulevard Pinel, F-69677 Bron Cedex, Lyon (France); Yver, Matthieu; Traversier, Aurelien [Equipe VirCell, Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Wolff, Thorsten [Division of Influenza/Respiratory Viruses, Robert Koch Institute, Nordufer 20, D-13353 Berlin (Germany); Riteau, Beatrice [Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Naffakh, Nadia [Institut Pasteur, Unite de Genetique Moleculaire des Virus Respiratoires, URA CNRS 3015, EA302 Universite Paris Diderot, Paris (France); and others

    2012-10-10

    Influenza A are nuclear replicating viruses which hijack host machineries in order to achieve optimal infection. Numerous functional virus-host interactions have now been characterized, but little information has been gathered concerning their link to the virally induced remodeling of the host cellular architecture. In this study, we infected cells with several human and avian influenza viruses and we have analyzed their ultrastructural modifications by using electron and confocal microscopy. We discovered that infections lead to a major and systematic disruption of nucleoli and the formation of a large number of diverse viral structures showing specificity that depended on the subtype origin and genomic composition of viruses. We identified NS1 and M1 proteins as the main actors in the remodeling of the host ultra-structure and our results suggest that each influenza A virus strain could be associated with a specific cellular fingerprint, possibly correlated to the functional properties of their viral components.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-26

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

  4. Mitochondrial ultrastructural and atpase changes during the life cycle of Ascaris Suum

    OpenAIRE

    Rodrick, G E; S. D. Long; W. A. Sodeman Junior; Smith, D. L.

    1982-01-01

    Ultrastructural morphology and ATPase specific activities of mitochondria isolated from 1-celled fertilized egg, 10-day embryo, 21-day infective larvae and adult body wall muscle of Ascaris suum and rat liver were determined and compared. Although cristae of both muscle and egg mitochondria contained numerous elementary particles with head pieces of conventional diameter (85 A), each muscle mitochondrion contained relatively few, short cristae with a diminished frequency of elementary particl...

  5. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    OpenAIRE

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M; Li, Hongjia; Wyman, Charles E; Langan, Paul; Art J. Ragauskas; Kumar, Rajeev

    2014-01-01

    Background Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial kn...

  6. 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

    2015-01-01

    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.

  7. Surface Analyses and Immune Reactivities of Major Cell Wall-Associated Proteins of Group A Streptococcus

    OpenAIRE

    Cole, Jason N; Ramirez, Ruben D.; Currie, Bart J.; Cordwell, Stuart J.; Djordjevic, Steven P.; Mark J Walker

    2005-01-01

    A proteomic analysis was undertaken to identify cell wall-associated proteins of Streptococcus pyogenes. Seventy-four distinct cell wall-associated proteins were identified, 66 of which were novel. Thirty-three proteins were immunoreactive with pooled S. pyogenes-reactive human antisera. Biotinylation of the GAS cell surface identified 23 cell wall-associated proteins that are surface exposed.

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

    DEFF Research Database (Denmark)

    Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha;

    2013-01-01

    The Reduced Wall Acetylation (RWA) proteins are involved in cell wall acetylation in plants. Previously, we described a single mutant, rwa2, which has about 20% lower level of O-acetylation in leaf cell walls and no obvious growth or developmental phenotype. In this study, we generated double...... 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...... in different combinations of triple mutants, suggesting their diversity in substrate preference. The overall degree of wall acetylation in the rwa quadruple mutant was reduced by 63% compared with the wild type, and histochemical analysis of the rwa quadruple mutant stem indicates defects in cell...

  9. Antigenicity and immunogenicity of an extract from the cell wall and cell membrane of Histoplasma capsulatum yeast cells.

    OpenAIRE

    Gómez, A M; Rhodes, J C; Deepe, G S

    1991-01-01

    In order to identify T-cell antigens from Histoplasma capsulatum yeast cells, we prepared a detergent extract of the cell wall and cell membrane of yeast-phase H. capsulatum G217B and analyzed its antigenicity and immunogenicity. Mice injected with viable H. capsulatum yeast cells or with 500 or 1,000 micrograms of the extract mounted a delayed-type hypersensitivity response to solubilized cell wall and cell membrane. Vaccination with this antigenic preparation conferred a protective immune r...

  10. Orbital wall infarction in child with sickle cell disease.

    Science.gov (United States)

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

    2015-12-01

    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. PMID:26790559

  11. Ultrastructure of cells in an initiating lateral root primordium of Raphanus sativus

    OpenAIRE

    F. Kadej; B. Rodkiewicz

    2015-01-01

    Lateral root primordia in Raphanus sativus had developed 10 hours after main root decapitation. The primordia consisted of three cell layers — basal layer continuous with the pericycle. The primordia were initiated by activated groups of pericycle cells. Inactive pericycle cells with a thin layer of parietal cytoplasme large central vacuole and well developed leucoplasts with starch grains were trans-formed into meristematic cells. During transformation the amount of cytoplasm and number of c...

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

    OpenAIRE

    Maria de Fatima D. Baptista-Farias; Anna Kohn

    1998-01-01

    An electron microscopic study of the vitelline follicles of Metamicrocotyla macracantha (Alexander, 1954) Koratha,1955 showed that they are composed of cells in different stages of development. The immature cells have a large nucleus, nucleolus, cytoplasm with free ribosomes and few mitochondria. The developing vitelline cells present granules which are small in the early stages, increasing with maturity. The mature cells have an extensive granular endoplasmic reticulum and droplets of shell-...

  13. Structure and ultrastructure of the pigmented cells in the adult dog pineal gland.

    OpenAIRE

    Calvo, J.; Boya, J; Garcia-Mauriño, J E; Lopez-Carbonell, A

    1988-01-01

    The light and electron microscopic features of pigmented cells in the adult dog pineal gland have been described. The presence of pigmented cells was a constant characteristic of the dog pineal gland, though wide variations in the amount of pigment could be found among different animals. Conversely, the localisation of pigmented cells was very constant on the basal surface of the proximal region of the pineal gland. Frequently, clusters of pigmented cells were seen in the posterior commissure...

  14. The Basal Level Ethylene Response is Important to the Wall and Endomembrane Structure in the Hypocotyl Cells of Etiolated Arabidopsis Seedlings

    Institute of Scientific and Technical Information of China (English)

    Chan Xu; Xiaoyan Gao; Xiaobin Sun; Chi-Kuang Wen

    2012-01-01

    The sub-cellular events that occur during the ethylene-modulated cell elongation were characterized by examining the ultra-structure of etiolated Arabidopsis seedling hypocotyl cells.Preventing the basal level ethylene response facilitated cell elongation,and the cells exhibited wall loosening and separation phenotype.Nearby the wall separation sites were frequently associated with an increase in the cortical rough endoplasmic reticulum (rER) membranes,the presence of paramural bodies,and the circular Golgi formation.The cortical rER proliferation and circular Golgi phenotype were reverted by the protein biosynthesis inhibitor cycloheximide.The cortical rER membranes were longer when the ethylene response was prevented and shortened with elevated ethylene responses.Proteomic changes between wild type and the ethylene-insensitive mutant ethylene insensitive2 (ein2) seedling hypocotyls indicated that distinct subsets of proteins involving endomembrane trafficking,remodeling,and wall modifications were differentially expressed.FM4-64 staining supported the proteomic changes,which indicated reduced endocytosis activity with alleviation of the ethylene response.The basal level ethylene response has an important role in endomembrane trafficking,biological materials transport and maintenance of the endomembrane organization.It is possible that endomembrane alterations may partly associate with the wall modifications,though the biological significance of the alterations should be addressed in future studies.

  15. The basal level ethylene response is important to the wall and endomembrane structure in the hypocotyl cells of etiolated Arabidopsis seedlings.

    Science.gov (United States)

    Xu, Chan; Gao, Xiaoyan; Sun, Xiaobin; Wen, Chi-Kuang

    2012-07-01

    The sub-cellular events that occur during the ethylene-modulated cell elongation were characterized by examining the ultra-structure of etiolated Arabidopsis seedling hypocotyl cells. Preventing the basal level ethylene response facilitated cell elongation, and the cells exhibited wall loosening and separation phenotype. Nearby the wall separation sites were frequently associated with an increase in the cortical rough endoplasmic reticulum (rER) membranes, the presence of paramural bodies, and the circular Golgi formation. The cortical rER proliferation and circular Golgi phenotype were reverted by the protein biosynthesis inhibitor cycloheximide. The cortical rER membranes were longer when the ethylene response was prevented and shortened with elevated ethylene responses. Proteomic changes between wild type and the ethylene-insensitive mutant ethylene insensitive2 (ein2) seedling hypocotyls indicated that distinct subsets of proteins involving endomembrane trafficking, remodeling, and wall modifications were differentially expressed. FM4-64 staining supported the proteomic changes, which indicated reduced endocytosis activity with alleviation of the ethylene response. The basal level ethylene response has an important role in endomembrane trafficking, biological materials transport and maintenance of the endomembrane organization. It is possible that endomembrane alterations may partly associate with the wall modifications, though the biological significance of the alterations should be addressed in future studies. PMID:22591458

  16. Ultrastructural Evidence of Exosome Secretion by Progenitor Cells in Adult Mouse Myocardium and Adult Human Cardiospheres

    Directory of Open Access Journals (Sweden)

    Lucio Barile

    2012-01-01

    Full Text Available The demonstration of beneficial effects of cell therapy despite the persistence of only few transplanted cells in vivo suggests secreted factors may be the active component of this treatment. This so-called paracrine hypothesis is supported by observations that culture media conditioned by progenitor cells contain growth factors that mediate proangiogenic and cytoprotective effects. Cardiac progenitor cells in semi-suspension culture form spherical clusters (cardiospheres that deliver paracrine signals to neighboring cells. A key component of paracrine secretion is exosomes, membrane vesicles that are stored intracellularly in endosomal compartments and are secreted when these structures fuse with the cell plasma membrane. Exosomes have been identified as the active component of proangiogenic effects of bone marrow CD34+ stem cells in mice and the regenerative effects of embryonic mesenchymal stem cells in infarcted hearts in pigs and mice. Here, we provide electron microscopic evidence of exosome secretion by progenitor cells in mouse myocardium and human cardiospheres. Exosomes are emerging as an attractive vector of paracrine signals delivered by progenitor cells. They can be stored as an “off-the-shelf” product. As such, exosomes have the potential for circumventing many of the limitations of viable cells for therapeutic applications in regenerative medicine.

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

    Directory of Open Access Journals (Sweden)

    Ying Luo

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

  18. Effects of spaceflight on polysaccharides of Saccharomyces cerevisiae cell wall.

    Science.gov (United States)

    Liu, Hong-Zhi; Wang, Qiang; Liu, Xiao-Yong; Tan, Sze-Sze

    2008-12-01

    Freeze-dried samples of four Saccharomyces cerevisiae strains, namely, FL01, FL03, 2.0016, and 2.1424, were subjected to spaceflight. After the satellite's landing on Earth, the samples were recovered and changes in yeast cell wall were analyzed. Spaceflight strains of all S. cerevisiae strains showed significant changes in cell wall thickness (P growth curve analysis showed spaceflight S. cerevisiae 2.0016 had a faster growth rate, shorter lag phase periods, higher final biomass, and higher content of beta-glucan. Genetic stability analysis showed that prolonged subculturing of spaceflight strain S. cerevisiae 2.0016 did not lead to the appearance of variants, indicating that the genetic stability of S. cerevisiae 2.0016 mutant could be sufficient for its exploitation of beta-glucan production. PMID:18797865

  19. Effect of plagiochin E, an antifungal macrocyclic bis(bibenzyl), on cell wall chitin synthesis in Candida albicans

    Institute of Scientific and Technical Information of China (English)

    Xiu-zhen WU; Ai-xia CHENG; Ling-mei SUN; Hong-xiang LOU

    2008-01-01

    Aim: To investigate the effect of plagiochin E (PLE), an antifungal macrocyclic bis(bibenzyl) isolated from liverwort Marchantia polymorpha L, on cell wall chitin synthesis in Candida albicans. Methods: The effect of PLE on chitin synthesis in Candida albicans was investigated at the cellular and molecular lev-els. First, the ultrastructural changes were observed under transmission electron microscopy (TEM). Second, the effects of PLE on chitin synthetase (Chs) activi-ties in vitro were assayed using 6-O-dansyl-N-acetylglucosamine as a fluorescent substrate, and its effect on chitin synthesis in situ was assayed by spheroplast regeneration. Finally, real-time RT-PCR was performed to assay its effect on the expression of Chs genes (CHS). Results: Observation under TEM showed that the structure of the cell wall in Candida albicans was seriously damaged, which suggested that the antifungal activity of PLE was associated with its effect on the cell wail. Enzymatic assays and spheroplast regeneration showed that PLE inhibited chitin synthesis in vitro and in situ. The results of the PCR showed that PLE significantly downregulated the expression of CHS1, and upregulated the expression of CHS2 and CHS3. Because different Chs is regulated at different stages of transcription and post-translation, the downregulation of CHS1 would decrease the level of Chs 1 and inhibit its activity, and the inhibitory effects of PLE on Chs2 and Chs3 would be at the post-translational level or by the inhibi-tion on the enzyme-active center. Conclusion: These results indicate that the antifungal activity of PLE would be attributed to its inhibitory effect on cell wall chitin synthesis in Candida albicans.

  20. Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

    Directory of Open Access Journals (Sweden)

    S Matsubara

    2010-01-01

    Full Text Available Glucose-6-phosphate dehydrogenase (G6PD is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly- developed enzyme-cytochemistry (copper-ferrocyanide method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

  1. Nitrate sensing and cell wall modification in Staphylococci

    OpenAIRE

    Niemann, Volker

    2015-01-01

    This thesis highlights two topics concerning the regulation of energy metabolism and the cell wall biosynthesis in Staphylococci. Most members of this genus are facultative anaerobic microorganisms able to respire on nitrate as final electron acceptor. The completely apathogenic organism Staphylococcus carnosus is used as starter culture in food industry. Dissimilatory nitrate reduction causes desired effects during the ripening process of sausages. First, the nitrate concentra...

  2. Transcriptome analysis of secondary cell wall development in Medicago truncatula

    OpenAIRE

    Wang, Huanzhong; Yang, Jung Hyun; Chen, Fang; Torres-Jerez, Ivone; Tang, Yuhong; Wang, Mingyi; Du, Qian; Cheng, Xiaofei; Wen, Jiangqi; Dixon, Richard

    2016-01-01

    Background Legumes are important to humans by providing food, feed and raw materials for industrial utilizations. Some legumes, such as alfalfa, are potential bioenergy crops due to their high biomass productivity. Global transcriptional profiling has been successfully used to identify genes and regulatory pathways in secondary cell wall thickening in Arabidopsis, but such transcriptome data is lacking in legumes. Results A systematic microarray assay and high through-put real time PCR analys...

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

    OpenAIRE

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

    2014-01-01

    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 thei...

  4. Cell-wall hemicelluloses as mobile carbon stores in plants

    OpenAIRE

    Schädel, Christina

    2009-01-01

    Hemicelluloses are the second most abundant polysaccharide in nature after cellulose. So far, the chemical heterogeneity of cell-wall hemicelluloses and the relatively large sample-volume required in existing methods represent major obstacles for large-scale, cross-species analyses of this important plant compounds. Here, we apply a new micro-extraction method to analyse hemicelluloses and the ratio of ‘cellulose and lignin’ to hemicelluloses in different tissues of 28 plant species comprisin...

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

    OpenAIRE

    Thygesen, Lisbeth G; Thybring, Emil E.; Johansen, Katja S.; Claus Felby

    2014-01-01

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

  6. Plant cell walls: New insights from ancient species

    DEFF Research Database (Denmark)

    Sørensen, Iben; Willats, William George Tycho

    2008-01-01

    ¿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....

  7. Cell wall perturbation sensitizes fungi to the antimalarial drug chloroquine

    OpenAIRE

    Islahudin, Farida; Khozoie, Combiz; Bates, Steven; Ting, Kang-Nee; Pleass, Richard J.; Avery, Simon V.

    2013-01-01

    Chloroquine (CQ) has been a mainstay of antimalarial drug treatment for several decades. Additional therapeutic actions of CQ have been described, including some reports of fungal inhibition. Here we investigated the action of CQ in fungi, including the yeast model Saccharomyces cerevisiae. A genomewide yeast deletion strain collection was screened against CQ, revealing that bck1Δ and slt2Δ mutants of the cell wall integrity pathway are CQ hypersensitive. This phenotype was rescued with sorbi...

  8. Enzyme Amplified Detection of Microbial Cell Wall Components

    Science.gov (United States)

    Wainwright, Norman R.

    2004-01-01

    This proposal is MBL's portion of NASA's Johnson Space Center's Astrobiology Center led by Principal Investigator, Dr. David McKay, entitled: 'Institute for the Study of Biomarkers in Astromaterials.' Dr. Norman Wainwright is the principal investigator at MBL and is responsible for developing methods to detect trace quantities of microbial cell wall chemicals using the enzyme amplification system of Limulus polyphemus and other related methods.

  9. Ultrastructure observation on the cells at different life history stages of Cryptocaryon irritans (Ciliophora: Prostomatea), a parasitic ciliate of marine fishes.

    Science.gov (United States)

    Ma, Rui; Ni, Bing; Fan, Xinpeng; Warren, Alan; Yin, Fei; Gu, Fukang

    2016-09-01

    Cells of Cryptocaryon irritans at different life history stages were studied using both light and electron microscopy. The characteristics of several organelles were revealed for the first time at the ultrastructural level. It was confirmed that the cytostome of trophonts, protomonts and theronts was surrounded by cilium-palp triplets rather than ciliary triplets. The nematodesmata underlying the circumoral dikinetids were single bundles, whereas these were always paired in Prorodontids. Toxicysts were present in late-stage tomonts and theronts, but were absent in trophonts and protomonts. We posited that toxicysts might play a role in infection and invasion of host-fish tissue by theronts. The adoral brosse was unlike that of any other family of the class Prostomatea based on its location and morphology. Membranous folds were present in trophonts, protomonts and theronts. These folds were longer and more highly developed in C. irritans than in exclusively free-living prostome ciliates suggesting that they might be linked to parasitism in C. irritans. Trophonts, protomonts and theronts had multiple contractile vacuoles. The basic ultrastructure of the contractile vacuole of C. irritans was similar to that of other kinetofragminophoran ciliates. They might play different roles in different stages of the life cycle since their ultrastructure varied among trophonts, protomonts and theronts. PMID:27460894

  10. Cardiomyocytes derived from human embryonic and induced pluripotent stem cells: comparative ultrastructure

    OpenAIRE

    Gherghiceanu, Mihaela; Barad, Lili; Novak, Atara; Reiter, Irina; Itskovitz-Eldor, Joseph; Binah, Ofer; Popescu, LM

    2011-01-01

    Abstract Induced pluripotent stem cells (iPSC) are generated from fully differentiated somatic cells that were reprogrammed into a pluripotent state. Human iPSC which can be obtained from various types of somatic cells such as fibroblasts or keratinocytes can differentiate into cardiomyocytes (iPSC-CM), which exhibit cardiac-like transmembrane action potentials, intracellular Ca2+ transients and contractions. While major features of the excitation-contraction coupling of iPSC-CM have been wel...

  11. Changes in alfalfa cell wall structure during vegetation

    Directory of Open Access Journals (Sweden)

    Božičković Aleksa Đ.

    2014-01-01

    Full Text Available The investigation was done on 141 samples of one alfalfa cultivar, collected from the same location during the first three growth cycles: spring growth, the first and the second regrowth. Within each growth cycle, sampling was done during the whole growing period, commencing when plant height was below 150 mm and continuing until plants were bearing ripe seeds. On all collected samples the following cell wall characteristics were determined: neutral detergent fibre (NDF, acid detergent fibre (ADF, acid detergent lignin (ADL, neutral detergent insoluble crude protein (NDICP, acid detergent insoluble crude protein (ADICP. Cellulose and hemicellulose were detected on the base of the mentioned chemical parameters. Significantly lower (p<0.01 content of aNDF, ADF, ADL, ADICP and cellulose is found in the second regrowth, while there were no significant differences between the other two growth cycles. Except in NDICP and ADICP, the increase in all accompanying components of the cell wall was observed, and expressed in average daily changes. There was no consistent trend in NDICP and ADICP. During the spring growth from late bud to full-bloom stage the ’plateau’ was observed. The plateau was represented as almost constant content of aNDF, ADF, ADL and cellulose. The correlations between all components of the cell wall were shown. The equation aNDF = 36.713 + 1.181 × ADF is recommended for conversion of ADF into aNDF in alfalfa. [Projekat Ministarstva nauke Republike Srbije, br. III 46012

  12. The ultrastructural changes in the liver cells induced by high doses of Benzodiazepine Tranquilizing drugs: An experimental transmission electron microscopic study on male guinea pigs

    International Nuclear Information System (INIS)

    Benzodiazepines are tranquilizing psychotropic drugs. Unfortunately, despite their therapeutic benefits, they are illegally consumed in high doses by some addicts to reach a sedative, exhilarative and euphoria state similar to that produced by narcotic substances. The present study, using transmission electron microscope on male guinea pigs, aims to investigate the potential ultrastructural changes in the liver cells induced by the high doses of Benzodiazepines. Animals in three treated groups administrated a daily combined dose consisted of (10mg Alprazolam with 10mg Diazepam/day/animal) for three different treatment periods: 7, 15, and 25 days. The ultrastructural examination of the hepatocytes of the animals treated for 15 days showed limited changes in the form of marginal heterochromatine accompanied with marginal nucleoli enlargement. On the other hand, severe ultrastructural damages are observed in the animals treated for 25 days, which appeared in the following various patterns: fatty degeneration of the hepatocytes as indicated by the accumulation of large number of lipid droplets in the cytoplasm, marked nuclear atrophy in some necrotic hepatocytes, massive nuclear degeneration in other hepatocytes, mitochondrial damages in the form of cristea destruction accompanied with abnormal oval shape, massive lysis of the cytoplasmic organelles with severe plasma membrane rupture. In conclusion, the observed ultrastructural damages in the present study may refer to the potential hepatotoxic effects of the high dose of Benzodiazepins. It is recommended that much more official restrictions should be applied on the pharmacies sector to prevent any illegal selling of these drugs in order to prevent abusers from obtaining them, as unfortunately in some developing countries the illegal selling of these drugs is known to occur due to the absence of official control. (author)

  13. Secondary cell wall polysaccharides in Bacillus anthracis and Bacillus cereus strains

    OpenAIRE

    Leoff, Christine

    2009-01-01

    This thesis presents a systematic comparison of cell wall carbohydrates, in particular the non classical secondary cell wall polysaccharides from closely related strains within the Bacillus cereus group. The results suggest that the cell wall glycosyl composition of the various Bacillus cereus group strains display differences that correlate with their phylogenetic relatedness. Comparative structural analysis of polysaccharide components that were released from the cell walls of the various s...

  14. Protein transport across the cell wall of monoderm Gram-positive bacteria

    OpenAIRE

    Forster, Brian M.; Marquis, Hélène

    2012-01-01

    In monoderm (single membrane) Gram-positive bacteria, the majority of secreted proteins are first translocated across the cytoplasmic membrane into the inner wall zone. For a subset of these proteins, final destination is within the cell envelope either as membrane-anchored or cell wall-anchored proteins, whereas another subset of proteins is destined to be transported across the cell wall into the extracellular milieu. Although the cell wall is a porous structure, there is evidence that, for...

  15. The cell wall and endoplasmic reticulum stress responses are coordinately regulated in Saccharomyces cerevisiae

    OpenAIRE

    Krysan, Damian J.

    2009-01-01

    The unfolded protein response (UPR) is an intracellular signaling pathway that regulates the cellular response to the accumulation of misfolded proteins in eukaryotes. Our group has demonstrated that cell wall stress activates UPR in yeast through signals transmitted by the cell wall integrity (CWI) mitogen-activated protein (MAP) kinase cascade. The UPR is required to maintain cell wall integrity; mutants lacking a functional UPR have defects in cell wall biosynthesis and are hypersensitive ...

  16. Homogenization of a system of elastic and reaction-diffusion equations modelling plant cell wall biomechanics

    OpenAIRE

    Ptashnyk, Mariya; Seguin, Brian

    2014-01-01

    In this paper we present a derivation and multiscale analysis of a mathematical model for plant cell wall biomechanics that takes into account both the microscopic structure of a cell wall coming from the cellulose microfibrils and the chemical reactions between the cell wall's constituents. Particular attention is paid to the role of pectin and the impact of calcium-pectin cross-linking chemistry on the mechanical properties of the cell wall. We prove the existence and uniqueness of the stro...

  17. Ultrastructure of Cajal-like interstitial cells in the human detrusor

    DEFF Research Database (Denmark)

    Rasmussen, Helle; Rumessen, Jüri J; Hansen, Alastair; Smedts, Frank; Horn, Thomas

    2009-01-01

    of interstitial cells were identified by TEM: ICC-L and fibroblast-like cells (FLC). ICC-L were bipolar with slender (0.04 microm) flattened dendritic-like processes, frequently forming a branching labyrinth network. Caveolae and short membrane-associated dense bands were present. Mitochondria, rough...

  18. Ultrastructure of interstitial cells of Cajal at the colonic submuscular border in patients with ulcerative colitis

    DEFF Research Database (Denmark)

    Rumessen, J J

    1996-01-01

    Submuscular interstitial cells of Cajal (ICC) are putative pacemaker cells of the colonic external muscle. Although motility disturbances and smooth muscle dysfunction are prevalent in patients with ulcerative colitis (UC), ICC have never been studied in this disease. The aim of this study was to...

  19. Innervation of amphibian reproductive system. Histological and ultrastructural studies.

    Science.gov (United States)

    Cisint, Susana; Crespo, Claudia A; Medina, Marcela F; Iruzubieta Villagra, Lucrecia; Fernández, Silvia N; Ramos, Inés

    2014-10-01

    In the present study we describe for the first time in anuran amphibians the histological and ultrastructural characteristics of innervation in the female reproductive organs. The observations in Rhinella arenarum revealed the presence of nerve fibers located predominantly in the ovarian hilium and in the oviduct wall. In both organs the nerves fibers are placed near blood vessels and smooth muscles fibers. In the present study the histological observations were confirmed using antibodies against peripherin and neurofilament 200 proteins. Ultrastructural analyses demonstrated that the innervation of the reproductive organs is constituted by unmyelinated nerve fibers surrounded by Schwann cells. Axon terminals contain a population of small, clear, translucent vesicles that coexist with a few dense cored vesicles. The ultrastructural characteristics together with the immunopositive reaction to tyrosine hydroxylase of the nerve fibers and the type of synaptic vesicles present in the axon terminal would indicate that the reproductive organs of R. arenarum females are innervated by the sympathetic division of the autonomic nervous system. PMID:24882461

  20. Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads

    Science.gov (United States)

    Dashtdar, Havva; Selvaratnam, Lakshmi; Balaji Raghavendran, Hanumantharao; Suhaeb, Abdulrazzaq Mahmod; Ahmad, Tunku Sara

    2016-01-01

    Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis. PMID:26966647

  1. [Ultrastructure of the subepithelial capillaries and venules in the forestomach of sheep].

    Science.gov (United States)

    Karmona, Kh; Kovachev, G

    1986-01-01

    Described is the ultrastructure of the subepithelial capillaries and venules in the forestomach, of sheep. The vessels have proved to be fenestrated, with an entire endothelial lining, the fenestrae being closed by a well contoured membrane (diaphragm). Certain differences were established in the wall of the subepithelial vessels of the individual compartments of the forestomach. The fenestral portions are usually located at the side that is closer to the basal epithelium, while within the deeper layers they are replaced by nonfenestrated endothelium. A well defined pericapillary space, full of cross, olblique, and longitudinal collagen fibres was found between capillaries and epithelial basal cells. There were a number of ultrastructural findings in the walls of the capillaries, venules, and epithelium, which could be referred to as morphologic indices of the active transport of metabolic substances. PMID:3727386

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

    DEFF Research Database (Denmark)

    Schneider, Tanja; Kruse, Thomas; Wimmer, Reinhard;

    2010-01-01

    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...

  3. Staphylococcus aureus Cell Wall Stress Stimulon Gene-lacZ Fusion Strains: Potential for Use in Screening for Cell Wall-Active Antimicrobials▿

    OpenAIRE

    Steidl, Rebecca; Pearson, Stacy; Stephenson, Robert E.; Ledala, Nagender; Sitthisak, Sutthirat; Wilkinson, Brian J; Jayaswal, Radheshyam K.

    2008-01-01

    lacZ fusion strains were constructed using the promoters of five cell wall stress stimulon genes: pbp2, tcaA, vraSR, sgtB, and lytR. All fusion strains were induced only in the presence of cell wall-active antibiotics, suggesting the potential of these strains for use in high-throughput screening for new cell wall-active agents.

  4. The Unfolded Protein Response Is Induced by the Cell Wall Integrity Mitogen-activated Protein Kinase Signaling Cascade and Is Required for Cell Wall Integrity in Saccharomyces cerevisiae

    OpenAIRE

    Scrimale, Thomas; DiDone, Louis; de Mesy Bentley, Karen L.; Krysan, Damian J.

    2009-01-01

    The yeast cell wall is an extracellular structure that is dependent on secretory and membrane proteins for its construction. We investigated the role of protein quality control mechanisms in cell wall integrity and found that the unfolded protein response (UPR) and, to a lesser extent, endoplasmic reticulum (ER)-associated degradation (ERAD) pathways are required for proper cell wall construction. Null mutation of IRE1, double mutation of ERAD components (hrd1Δ and ubc7Δ) and ire1Δ, or expres...

  5. 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

    2007-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-22

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

  7. A Model for Cell Wall Dissolution in Mating Yeast Cells: Polarized Secretion and Restricted Diffusion of Cell Wall Remodeling Enzymes Induces Local Dissolution

    OpenAIRE

    Huberman, Lori B.; Murray, Andrew W.

    2014-01-01

    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...

  8. Plexus muscularis profundus and associated interstitial cells. II. Ultrastructural studies of mouse small intestine

    DEFF Research Database (Denmark)

    Rumessen, J J; Thuneberg, L; Mikkelsen, H B

    1982-01-01

    A), synapse-like contacts to interstitial cells of Cajal (ICC-III). Presynaptic densities were frequent in type I endings. A direct innervation of muscle cells via PMP was only very occasionally suggested. ICC-III possessed a basal lamina and numerous caveolae associated with subsurface SER......, and the lack of caveolae and a basal lamina. FLC never participated in synaptic arrangements or gap junctions. Macrophage-like cells were occasionally encountered. It is concluded that possible efferent and afferent nerve terminals in PMP may chiefly, if not exclusively, innervate ICC-III, the...

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    BACKGROUND: Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally...... 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...... 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...

  10. Response of the common cutworm Spodoptera litura to zinc stress: Zn accumulation, metallothionein and cell ultrastructure of the midgut

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Yinghua [Key Laboratory of Agro-Environments in Tropics, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642 (China); Key Laboratory of Agroecology and Rural Environment of Guangdong Regular Higher Education Institutions, South China Agricultural University, Guangzhou 510642 (China); Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642 (China); State Key Laboratory of Biological Control and Institute of Entomology, Sun Yat-sen University, Guangzhou 510275 (China); Zhang, Guren [State Key Laboratory of Biological Control and Institute of Entomology, Sun Yat-sen University, Guangzhou 510275 (China); Wang, Jianwu, E-mail: wangjw@scau.edu.cn [Key Laboratory of Agro-Environments in Tropics, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642 (China); Key Laboratory of Agroecology and Rural Environment of Guangdong Regular Higher Education Institutions, South China Agricultural University, Guangzhou 510642 (China); Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642 (China)

    2012-11-01

    By exposing the common cutworm Spodoptera litura Fabricius larvae to a range of Zinc (Zn) stress, we investigated the effects of dietary Zn on Zn accumulation, metallothionein (MT), and on the ultrastructure of the midgut. The techniques we used were inductively coupled plasma-atomic emission spectrometer (ICP-AES), real-time PCR combined with cadmium-hemoglobin total saturation, and transmission electron microscopy (TEM), respectively. There was a significant dose-response relationship between the Zn accumulations in the midgut of the larvae and the Zn concentrations in the diet. Furthermore, both MT content and MT gene expression in the midgut were significantly induced in the 50-500 mg Zn/kg treatments, and were significantly positively correlated with the Zn accumulations in the midgut. When S. litura larvae were fed with the diet treated with 500 mg Zn/kg, Zn accumulation and MT content in the midgut was 4450.85 mg Zn/kg and 372.77 mg/kg, respectively, thereafter there was a little increase; the level of MT gene expression was maximal, thereafter there was a sharp decrease. TEM showed that numerous electron-dense granules (EDGs) and vacuoles appeared in the cytoplasm of the midgut cells, their number and size being closely correlated with the Zn accumulations in the midgut. Moreover, the nuclei were strongly influenced by Zn stress, evidenced by chromatin condensation and irregular nuclear membranes. Therefore, after being exposed to Zn in the threshold (500 mg Zn/kg) range, S. litura larvae could accumulate Zn in the midgut, which led to the induction of MT and changes in cell ultrastructure (mainly the presence of EDGs). The induction of MT and precipitation of Zn in EDGs may be the effective detoxification mechanisms by which the herbivorous insect S. litura defends itself against heavy metals. -- Graphical abstract: When the herbivorous insect Spodoptera litura Fabricius larvae were fed on the artificial diet with different concentrations of Zn, amounts of

  11. Early ultrastructural lesions in kidney cells after intravenous administration of 239 plutonium citrate in the rat

    International Nuclear Information System (INIS)

    After intravenous administration of (5 x 2.3 kBq and 5 x 9.25 kBq) plutonium citrate in adult male Sprague Dawley rats, their kidneys are withdrawn and prepared for observation under a transmission electron microscope. Seven days after the first injections, deep cellular alterations are observed in the proximal convoluted tubules. These alterations are mainly mitochondrial. The affected mitochondria are of swollen aspect and have their cristae partially or completely destroyed. Nevertheless within the same tubule we observe non altered cells directly in contact with deeply altered cells. In all the cases the lysosomes of the altered cells appear to be perfectly normal. The cell nuclei are mostly unaltered but a few cases of nuclear fragmentation exist. We also notice some architectural modifications in the brush border and in the betacytomembranes of the proximal convoluted tubule. Equally important mitochondrial alterations are also noticed in the different varieties of glomerular cells. We observe no other glomerular alterations. The major subcellular alterations in the proximal convoluted tubules and in the different varieties of glomerular cells deeply contrast with the distal convoluted tubules which are found to be totally unaltered. These mitochondrial alterations may be due to the α particle disintegration of plutonium which may either directly react with the mitochondria or, through the products of radiolysis of water react with the mitochondria respiration process. However the direct chemo-toxicity of plutonium cannot be neglected. (Authors). 21 refs., 1 fig

  12. The digestive cells of the hepatopancreas in Aplysia depilans (Mollusca, Opisthobranchia): ultrastructural and cytochemical study.

    Science.gov (United States)

    Lobo-da-Cunha, A

    2000-02-01

    Digestive cells are the most abundant cell type in the digestive diverticula of Aplysia depilans. These are tall columnar or club shaped cells, covered with microvilli on their apical surface. A large number of endocytic vesicles containing electron-dense substances can be found in the apical zone, but the presence of many heterolysosomes of large diameter is the main feature of these cells. Glycogen particles and some lipid droplets were also observed. Peroxisomes with a circular or oval profile were common, but crystalline nucleoids were not detected in them, although a dense spot in the matrix was observed in a few cases. These organelles were strongly stained after cytochemical detection of catalase activity. The Golgi stacks are formed by 4 or 5 cisternae, with dilated zones containing electron dense material. Arylsulphatase activity was detected in the Golgi stacks and also in lysosomes. Cells almost entirely occupied by a very large vacuole containing a residual dense mass seem to be digestive cells in advanced stages of maturation. The observation of semithin and ultrathin sections indicates that these very large vacuoles are the result of a fusion among the smaller lysosomes. Some images suggest that the content of these large vacuoles is extruded into the lumen of the digestive diverticula. PMID:10798317

  13. Expansins are among plant cell wall modifying agents specifically expressed during development of nematode-induced syncytia

    OpenAIRE

    Fudali, Sylwia; Sobczak, Miroslaw; Janakowski, Slawomir; Griesser, Michaela; Grundler, Florian MW; Golinowski, Wladyslaw

    2008-01-01

    Cyst nematodes are economically important pests. As obligatory biotrophic endoparasites they invade host roots and induce formation of syncytia, structures that serve them as the only source of nutrients. During syncytium development, extensive cell wall modifications take place. Cell wall dissolution occurs during cell wall opening formation, cell walls expand during hypertrophy of syncytial elements and local cell wall synthesis leads to the thickening of syncytial cell wall and the formati...

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

    Science.gov (United States)

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

    2012-09-19

    Procyanidins can bind cell wall material in raw product, and it could be supposed that the same mechanism of retention of procyanidins by apple cell walls takes place in cooked products. To evaluate the influence of cell wall composition and disassembly during cooking on the cell walls' capacity to interact with procyanidins, four cell wall materials differing in their protein contents and physical characteristics were prepared: cell wall with proteins, cell wall devoid of protein, and two processed cell walls differing by their drying method. Protein contents varied from 23 to 99 mg/g and surface areas from 1.26 to 3.16 m(2)/g. Apple procyanidins with an average polymerization degree of 8.7 were used. The adsorption of apple procyanidins on solid cell wall material was quantified using the Langmuir isotherm formulation. The protein contents in cell wall material had no effect on procyanidin/cell wall interactions, whereas modification of the cell wall material by boiling, which reduces pectin content, and drying decreased the apparent affinity and increased the apparent saturation levels when constants were expressed relative to cell wall weight. However, boiling and drying increased apparent saturation levels and had no effect on apparent affinity when the same data were expressed per surface units. Isothermal titration calorimetry indicated strong affinity (K(a) = 1.4 × 10(4) M(-1)) between pectins solubilized by boiling and procyanidins. This study higllights the impact of highly methylated pectins and drying, that is, composition and structure of cell wall in the cell wall/procyanidin interactions. PMID:22861056

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

    Science.gov (United States)

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

    2010-07-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation, and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, the mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. Several genes affecting MSC differentiation, pectin synthesis, and mucilage release have been identified and additional genes involved in these and related processes including pectin secretion and the mechanical alteration of cell walls await to be discovered. PMID:20505351

  16. Cell wall pH and auxin transport velocity

    Science.gov (United States)

    Hasenstein, K. H.; Rayle, D.

    1984-01-01

    According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport.

  17. Scattering properties of microalgae: the effect of cell size and cell wall

    Science.gov (United States)

    Svensen, Øyvind; Frette, Øyvind; Rune Erga, Svein

    2007-08-01

    The main objective of this work was to investigate how the cell size and the presence of a cell wall influence the scattering properties of the green microalgae Chlamydomonas reinhardtii. The growth cycle of two strains, one with a cell wall and one without, was synchronized to be in the same growth phase. Measurements were conducted at two different phases of the growth cycle on both strains of the algae. It was found that the shape of the scattering phase function was very similar for both strains at both growth phases, but the regular strain with a cell wall scatters more strongly than the wall-less mutant. It was also found that the mutant strain has a stronger increase in scattering than the regular strain, as the algae grow, and that the scattering from the regular strain is more wavelength dependent than from the mutant strain.

  18. Ultrastructure of interstitial cells of Cajal in myenteric plexus of human colon

    DEFF Research Database (Denmark)

    Rumessen, Jüri Johannes; Vanderwinden, Jean-Marie; Rasmussen, Helle;

    2009-01-01

    had myoid features such as scattered caveolae, prominent intermediate filaments, and cytoplasmic dense bodies. We found characteristic dense membrane-associated bands with a patchy basal lamina, invaginating cellular protrusions (peg and socket junctions) between ICC and between ICC and muscle cells......, and close contacts (<100 nm) between ICC and nerves. No gap junctions were observed. Fibroblast-like cells (FLC) were abundant showing well-developed secretory organelles, including coated vesicles, but lacked prominent intermediate filaments and caveolae. FLC had a patchy basal lamina, and peg and...

  19. Immunotherapy with BCG cell wall plus irradiated tumor cells

    International Nuclear Information System (INIS)

    Two different fibrosarcomas (MCB-I, MCB-II) were induced by methylcholcholanthrene in syngeneic Balb/C mice were used. The tumor cells irradiated with 5,000 to 30,000 rads did not growth in mice on 30 days after inoculation. The viable tumor cells were challenged intradermally to mice on 7 days after inoculation of the tumor cells irradiated with 5,000 to 30,000 rads. The challenged tumor cells were all rejected at 30 days after inoculation. Mice were challenged with 5 x 105 viable tumor cells on 7 days after inoculation of 103 to 108 irradiated tumor cells. Mice pretreated with 105 or 106 irradiated tumor cells rejected the tumor cells completely. The viable tumor cells were challenged to mice on 7 days after inoculation of BCG-CW emulsion plus 106 irradiated tumor cells. 0, 50, 100, 200, and 400 mu g of BCG-CW emulsion were mixed in 106 irradiated tumor cells. Optimal dosage of BCG-CW emulsion was 50 or 100 mu g. BCG-CW emulsion plus irradiated tumor cells were injected subcutaneously to the mice after tumor cells inoculation. Three injections of the vaccine significantly suppressed the tumor outgrowth, but not one or two injections in no-treated mice. However, in the mice pretreated with BCG-CW emulsion, the tumor growth was significantly suppressed by one or two injections of the vaccine. Especially, the three injections of the vaccine significantly suppressed the tumor growth and the 25% of the mice were completely cured. The effect of the vaccine was almost the same grade by contralateral or ipsilateral treatment. The irradiated MCB-II tumor cells plus BCG-CW emulsion were not effective to the MCB-1 tumor bearing mice, suggesting the anti-tumor effect of this vaccine was immunologically specific

  20. Immunotherapy with BCG cell wall plus irradiated tumor cells

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-04-01

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

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

    OpenAIRE

    Domozych, David S

    2014-01-01

    Penium margaritaceum is a new and valuable unicellular model organism for studying plant cell wall structure and developmental dynamics. This charophyte has a cell wall composition remarkably similar to the primary cell wall of many higher plants and clearly-defined inclusive zones containing specific polymers. Penium has a simple cylindrical phenotype with a distinct region of focused wall synthesis. Specific polymers, particularly pectins, can be identified using monoclonal antibodies rais...

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

    Energy Technology Data Exchange (ETDEWEB)

    Varner, J.E.

    1993-01-01

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

  3. Ultrastructure of interstitial cells of Cajal associated with deep muscular plexus of human small intestine

    DEFF Research Database (Denmark)

    Rumessen, J J; Mikkelsen, H B; Thuneberg, L

    1992-01-01

    (with a continuous basal lamina, caveolae, intermediate filaments, dense bodies, dense bands, and a well-developed subsurface smooth endoplasmic reticulum), but the arrangement of organelles was clearly different, and cisternae of granular endoplasmic reticulum were abundant. Interstitial cells of Cajal...

  4. Effects of hypothyroidism on the ultrastructure of rat pancreatic acinar cells: a stereological analysis

    OpenAIRE

    Blanco-Molina, A.; González-Reyes, J. A.; Torre-Cisneros, J; López-Miranda, J.; Nicolás, M.; Pérez-Jiménez, F.

    1991-01-01

    The morphological and stereological characteristics of the exocrine pancreas subcellular organelles from healthy and thyroidectomized rats have been studied. The acinar tissue from hypothyroid rats showed an interstitial edema and evidence of degenerative processes. Stereological parameters of zymogen granules were significantly reduced in thyroidectomized rats. The hypothyroidism induced degenerative changes in the pancreatic acinar cells as well as a decr...

  5. Ultrastructural features of organization of the cell and pirenoids in Stichococcus-like algae

    Directory of Open Access Journals (Sweden)

    Victoria M. Karbovska

    2014-04-01

    Full Text Available The results of SEM study of cell organization and some feature of the structure of pyrenoids in several authentic strains of the genus Stichococcus Nägeli from ACKU collection are reported. Our results showed a variety of organizations of the pyrenoid in this group of green microalgae and allowed to describe five main types of pyrenoids.

  6. Liquid crystal-type assembly of native cellulose-glucuronoxylans extracted from plant cell wall.

    Science.gov (United States)

    Reis, D; Vian, B; Chanzy, H; Roland, J C

    1991-01-01

    In numerous plant cell walls, the cellulose microfibrils are arranged in a helicoidal pattern which has been considered as an analog to a cholesteric order. Here, we report on the spontaneous helicoidal organization which occurs in acellular conditions from aqueous suspensions of cellulose. The cellulosic mucilage of mature seeds of quince (Cydonia oblonga L) was studied both in situ (pre-release mucilage) and after water extraction and in in vitro re-assembly (prolonged high speed ultracentrifugation, further progressive dehydration and embedding in LR White methacrylate or hydrosoluble melamine resin). The cellulosic component was characterized by the use of cellobiohydrolase (CBH1) bound to colloidal gold, and the glucuronic acid residues of the xylan matrix were characterized by the use of cationised gold. Inside the seeds, the pre-release mucilage is mostly helicoidal, with the occurrence of more or less ordered domains, which indicate a fluid organization relevant to an actual liquid crystal state. Cytochemical tests revealed the tight association between cellulose and glucuronoxylans, the latter constituting a charged coat around each microfibril. Following the hydration of the seed, a cellulosic suspension was extracted in which microfibrils were totally dispersed. The progressive dehydration of the suspension gave rise to concentrated viscous drops. Ultrastructural observations revealed the occurrence of multidomain organization, from non-ordered to cholesteric-like regions, revealing that the mucilage is at the same time crystalline and liquid. This constitutes the first demonstration that liquid crystal type assemblies can arise from crystalline and biological cellulose in aqueous suspension. It strengthens the hypothesis that a transient liquid crystal state must occur during the cellulose ordering. The possible morphogenetic role of the glucuronoxylans in the cholesteric organization of the cellulose is discussed. PMID:1804508

  7. Ultrastructural study of vitellogenesis of Ligula intestinalis (Diphyllobothriidea) reveals the presence of cytoplasmic-like cell death in cestodes

    Czech Academy of Sciences Publication Activity Database

    Yoneva, Aneta; Scholz, Tomáš; Młocicki, D.; Kuchta, Roman

    2015-01-01

    Roč. 12, DEC 4 2015 (2015), s. 35. ISSN 1742-9994 R&D Projects: GA ČR GAP506/12/1632 Institutional support: RVO:60077344 Keywords : Vitellogenesis * Ultrastructure * Paraptosis * Cestoda * Diphyllobothriidea * Ligula intestinalis Subject RIV: EG - Zoology Impact factor: 3.051, year: 2014

  8. Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics

    Directory of Open Access Journals (Sweden)

    Berger-Bächi Brigitte

    2011-01-01

    Full Text Available Abstract Background Staphylococcus aureus activates a protective cell wall stress stimulon (CWSS in response to the inhibition of cell wall synthesis or cell envelope damage caused by several structurally and functionally different antibiotics. CWSS induction is coordinated by the VraSR two-component system, which senses an unknown signal triggered by diverse cell wall active agents. Results We have constructed a highly sensitive luciferase reporter gene system, using the promoter of sas016 (S. aureus N315, which detects very subtle differences in expression as well as measuring > 4 log-fold changes in CWSS activity, to compare the concentration dependence of CWSS induction kinetics of antibiotics with different cell envelope targets. We compared the effects of subinhibitory up to suprainhibitory concentrations of fosfomycin, D-cycloserine, tunicamycin, bacitracin, flavomycin, vancomycin, teicoplanin, oxacillin, lysostaphin and daptomycin. Induction kinetics were both strongly antibiotic- and concentration-dependent. Most antibiotics triggered an immediate response with induction beginning within 10 min, except for tunicamycin, D-cycloserine and fosfomycin which showed lags of up to one generation before induction commenced. Induction characteristics, such as the rate of CWSS induction once initiated and maximal induction reached, were strongly antibiotic dependent. We observed a clear correlation between the inhibitory effects of specific antibiotic concentrations on growth and corresponding increases in CWSS induction kinetics. Inactivation of VraR increased susceptibility to the antibiotics tested from 2- to 16-fold, with the exceptions of oxacillin and D-cycloserine, where no differences were detected in the methicillin susceptible S. aureus strain background analysed. There was no apparent correlation between the induction capacity of the various antibiotics and the relative importance of the CWSS for the corresponding resistance phenotypes

  9. Chromatin and Cell Wall Staining of Schizosaccharomyces pombe.

    Science.gov (United States)

    Hagan, Iain M

    2016-01-01

    Fission yeasts grow by tip extension, maintaining a constant width until they reach a critical size threshold and divide. Division by medial fission-which gives these yeast their name-generates a new end that arises from the site of cytokinesis. The old end, which was produced during the previous cell cycle, initiates progression of the new cell cycle, and in G2, the new end is activated in a process termed new-end takeoff (NETO). In this protocol, the fluorescent stains calcofluor and 4',6-diamidino-2-phenylindole (DAPI) are used to give a rapid and informative assessment of morphogenesis and cell-cycle progression in the fission yeast Schizosaccharomyces pombe Calcofluor reveals the timing of NETO because it stains the birth scars that are generated at new ends by cytokinesis less efficiently than the rest of the cell wall. Intense calcofluor staining of the septum and measurement of cell length are also widely used to identify dividing cells and to gauge the timing of mitotic commitment. Staining nuclei with DAPI identifies mono- and binucleated cells and complements the calcofluor staining procedure to evaluate the stages of the cell cycle and identify mitotic errors. Equally simple DAPI staining procedures reveal chromatin structure in higher resolution, facilitating more accurate staging of mitotic progression and characterization of mitotic errors. PMID:27250942

  10. Aqueous Diffusion Pathways as a Part of the Ventricular Cell Ultrastructure

    OpenAIRE

    Parfenov, A. S.; Salnikov, V.; Lederer, W.J.; Lukyánenko, V.

    2005-01-01

    The physical organization of the ventricular myocyte includes barriers for the movement of objects of varying dimensions ranging from ions to solid particles. There are two kinds of diffusion in the cell: lateral (in membranes) and aqueous. Here we examine the size constraints of aqueous diffusion pathways and discuss their impact on cellular physiology. Calibrated gold nanoparticles were used to probe the accessibility of the entire transverse-axial tubular system (TATS), the sarcoplasm, and...

  11. Towards an atlas of mammalian cell ultrastructure by cryo soft X-ray tomography

    OpenAIRE

    Müller, Waltraud G.; Heymann, J. Bernard; Nagashima, Kunio; Guttmann, Peter; Werner, Stephan; Rehbein, Stefan; Schneider, Gerd; McNally, James G

    2011-01-01

    We provide a catalog of 3D cryo soft X-ray tomography (cryo-SXT) images obtained from ~6–12 µm thick mouse adenocarcinoma cells. Included are multiple representative images of nuclei, nucleoli, nuclear membrane, nuclear membrane channels, mitochondria, lysosomes, endoplasmic reticulum, filaments and plasma membrane, plus three structures not previously described by cryo-SXT, namely Golgi, microvilli and nuclear-membrane blebs. Sections from the 3D cryo-SXT tomograms for all the preceding stru...

  12. Ultrastructural and biochemical studies of two dynamically expressed cell surface determinants on Candida albicans.

    OpenAIRE

    Brawner, D L; Cutler, J E

    1986-01-01

    Variability in the expression of two different cell surface carbohydrate determinants was examined with two agglutinating immunoglobulin M monoclonal antibodies (H9 and C6) and immunoelectron microscopy during growth of three strains of Candida albicans. A single strain of Candida parapsilosis did not express either antigen at any time during growth. Antigens were detected on the surface of C. albicans by agglutination tests with either H9 or C6 over a 48-h growth period. The difference in sp...

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

    Science.gov (United States)

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

    2015-09-23

    The unraveling of crushed grapes by maceration enzymes during winemaking is difficult to study because of the complex and rather undefined nature of both the substrate and the enzyme preparations. In this study we simplified both the substrate, by using isolated grape skin cell walls, and the enzyme preparations, by using purified enzymes in buffered conditions, to carefully follow the impact of the individual and combined enzymes on the grape skin cell walls. By using cell wall profiling techniques we could monitor the compositional changes in the grape cell wall polymers due to enzyme activity. Extensive enzymatic hydrolysis, achieved with a preparation of pectinases or pectinases combined with cellulase or hemicellulase enzymes, completely removed or drastically reduced levels of pectin polymers, whereas less extensive hydrolysis only opened up the cell wall structure and allowed extraction of polymers from within the cell wall layers. Synergistic enzyme activity was detectable as well as indications of specific cell wall polymer associations. PMID:26309153

  14. Scrotal angiokeratoma (Fordyce): histopathological and ultrastructural findings.

    Science.gov (United States)

    Gioglio, L; Porta, C; Moroni, M; Nastasi, G; Gangarossa, I

    1992-01-01

    Bioptic findings related to four cases of scrotal angiokeratoma-Fordyce, were studied under light and electron microscopy. A particular heterogeneity of the structural and ultrastructural patterns typical of this lesion was thus observed. Light microscopy study pointed out, in particular, different degrees of dilation of papillary vessels, whereas ultrastructural study highlighted marked alterations of endothelial cells with structural and quantitative modifications of cytoplasmic organelles. PMID:1576434

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

    International Nuclear Information System (INIS)

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

  16. Members of the Hsp70 family of proteins in the cell wall of Saccharomyces cerevisiae.

    OpenAIRE

    López-Ribot, J L; Chaffin, W L

    1996-01-01

    Western blot (immunoblot) analysis of cell wall and cytosolic extracts obtained from parental and ssa1 and ssa2 single- and double-mutant strains of Saccharomyces cerevisiae showed that the heat shock protein 70 (Hsp70) products of these genes, previously thought to be restricted to the cell interior, are also present in the cell wall. A cell wall location was further confirmed by indirect immunofluorescence with intact cells and biotinylation of extracellular Hsp70. Hsp70s have been implicat...

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

    Science.gov (United States)

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

    2015-12-01

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

  18. Nutrient depletion modifies cell wall adsorption activity of wine yeast.

    Science.gov (United States)

    Sidari, R; Caridi, A

    2016-06-01

    Yeast cell wall is a structure that helps yeasts to manage and respond to many environmental stresses. The mannosylphosphorylation is a modification in response to stress that provides the cell wall with negative charges able to bind compounds present in the environment. Phenotypes related to the cell wall modification such as the filamentous growth in Saccharomyces cerevisiae are affected by nutrient depletion. The present work aimed at describing the effect of carbon and/or nitrogen limitation on the aptitude of S. cerevisiae strains to bind coloured polyphenols. Carbon- and nitrogen-rich or deficient media supplemented with grape polyphenols were used to simulate different grape juice conditions-early, mid, 'adjusted' for nitrogen, and late fermentations. In early fermentation condition, the R+G+B values range from 106 (high adsorption, strain Sc1128) to 192 (low adsorption, strain Σ1278b), in mid-fermentation the values range from 111 (high adsorption, strain Sc1321) to 258 (low adsorption, strain Sc2306), in 'adjusted' for nitrogen conditions the values range from 105 (high adsorption, strain Sc1321) to 194 (low adsorption, strain Sc2306) while in late fermentation conditions the values range from 101 (high adsorption, strain Sc384) to 293 (low adsorption, strain Sc2306). The effect of nutrient availability is not univocal for all the strains and the different media tested modified the strains behaviour. In all the media the strains show significant differences. Results demonstrate that wine yeasts decrease/increase their parietal adsorption activity according to the nutrient availability. The wide range of strain variability observed could be useful in selecting wine starters. PMID:27116955

  19. A radioimmunoassay for lignin in plant cell walls

    International Nuclear Information System (INIS)

    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 β-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 ηg/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. 125I 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 NaClO2 delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed

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

    Science.gov (United States)

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

    2012-09-01

    The lignification process in poplar tension wood lignified cell wall layers, specifically the S(1) and S(2) layers and the compound middle lamella (CML), was analysed using ultraviolet (UV) and transmission electron microscopy (TEM). Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the lignified cell wall layers had completed their lignification before the deposition of G-layers, or, on the contrary, if lignification of these layers was still active during G-layer formation. Observations using UV microscopy and TEM indicated that both UV absorbance and the degree of potassium permanganate staining increased in the CML and S(1) and S(2) layers during G-layer formation, suggesting that the lignification of these lignified layers is still in progress during G-layer formation. In the context of the cell-autonomous monolignol synthesis hypothesis, our observations suggest that monolignols must go through the developing G-layer during the lignification of CML and the S(1) and S(2) layers. The alternative hypothesis of external synthesis (in the rays) does not require that monolignols go through the G-layer before being deposited in the CML, or the S(1) and S(2) layers. Interestingly, the previous observation of lignin in the poplar G-layer was not confirmed with the microscopy techniques used in the present study. PMID:22933655

  1. X-ray and proton induced ultrastructural changes in Chlamydomonas reinhardi, with special reference to the dividing cell

    International Nuclear Information System (INIS)

    Liquid cultures were exposed to 9000 R x-irradiation delivered at approximately 600 R/min. This produced 69 percent mortality in the 137c wild type strain and 71 percent mortality in the acetate-requiring strain ac-31. Irradiated and control cells were fixed for electron microscopic examination at intervals up to five days post exposure. Proton-irradiations using a positive ion Van de Graff accelerator were administered to monolayers of cells attached to Millipore filters. Irradiated and control cells were later resuspended and incubated in liquid culture medium. The dose rate was approximately 20 kilorad/second for thin targets with the dose monitored with a solid state detector. Distinctive fine structural responses were observed for the two kinds of radiation at the indicated exposure levels. Alterations affecting the nucleus were prominent after x-irradiation. Nuclei were observed in which non-nucleolar condensations and swollen nuclear envelopes were evident. Nuclear envelope rupture was noted when cells were in an advanced state of disorganization. Multiple nuclei per cell were also observed. Proton-irradiation often resulted in both live and dead daughter cells within the same mother cell wall. Changes in the chloroplast and mitochondria were seen after both types of irradiation. Two features absent in control cells were of special interest. Following x- and proton-irradiation, cells were observed which remained joined in configurations closely resembling division profiles or division conformations. Irradiated cells also possessed chromosomes and spindle fibers at a time not characteristic for such events in control cells

  2. Absence of correlation between rates of cell wall turnover and autolysis shown by Bacillus subtilis mutants.

    OpenAIRE

    Vitković, L; Cheung, H. Y.; Freese, E

    1984-01-01

    Bacillus subtilis mutants with reduced rates of cell wall autolysis reached a constant rate of wall turnover after a longer lag than the standard strain but eventually showed the same turnover rate. In reverse, a turnover-deficient mutant autolysed at a slightly higher rate than the standard strain. Consequently, there is no correlation between the rates of cell wall turnover and autolysis.

  3. Cell wall loosening proteins of the stigma exudate

    OpenAIRE

    Nieuwland, J.H.

    2004-01-01

    Outline of the thesis: The idea, formulated by Cosgrove, that cell wall loosening of the maternal tissue facilitates pollen tube growth is a central theme of this thesis. This idea was originally proposed for beta-expansins released by maize pollen. Since the pollen coat of dry stigma type plants, like maize, bears a functional similarity with the exudate of wet stigma type plants (e.g. tobacco and petunia), this research was started with the analysis of the putative function of the pistil-sp...

  4. Clinical analysis of lateral oropharyngeal-wall squamous cell carcinoma

    International Nuclear Information System (INIS)

    We retrospectively reviewed 98 cases of lateral-oropharyngeal wall squamous cell carcinoma seen from January 1999 to March 2011. The majority-75 cases-involeved advanced cancer. For these, we conducted concurrent chemoradiotherapy (CCRT) with cisplatin, docetaxel, and 5-FU from 2007. Five-year overall survival was 64.4%. In advanced cases, three-year overall survival was 77.8% in surgery, 71.2% in radiation therapy, and 84.6% in CCRT. While no statistically significant difference was seen, CCRT, appeared to provide more curative effectiveness. (author)

  5. Mass spectrometry for characterizing plant cell wall polysaccharides

    Directory of Open Access Journals (Sweden)

    Stefan eBauer

    2012-03-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  7. 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

    2004-01-01

    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.

  8. Intracellular Target-Specific Accretion of Cell Penetrating Peptides and Bioportides: Ultrastructural and Biological Correlates.

    Science.gov (United States)

    Jones, Sarah; Uusna, Julia; Langel, Ülo; Howl, John

    2016-01-20

    Cell penetrating peptide (CPP) technologies provide a viable strategy to regulate the activities of intracellular proteins that may be intractable to other biological agents. In particular, the cationic helical domains of proteins have proven to be a reliable source of proteomimetic bioportides, CPPs that modulate the activities of intracellular proteins. In this study we have employed live cell imaging confocal microscopy to determine the precise intracellular distribution of a chemically diverse set of CPPs and bioportides. Our findings indicate that, following efficient cellular entry, peptides are usually accreted at intracellular sites rather than being freely maintained in an aqueous cytosolic environment. The binding of CPPs to proteins in a relatively stable manner provides a molecular explanation for our findings. By extension, it is probable that many bioportides influence biological processes through a dominant-negative influence upon discrete protein-protein interactions. As an example, we report that bioportides derived from the leucine-rich repeat kinase 2 discretely influence the biology and stability of this key therapeutic target in Parkinson's disease. The intracellular site-specific accretion of CPPs and bioportides can also be readily modulated by the attachment of larger cargoes or, more conveniently, short homing motifs. We conclude that site-specific intracellular targeting could be further exploited to expand the scope of CPP technologies. PMID:26623479

  9. Rhodiola Rosea as antioxidant in red blood cells: ultrastructural and hemolytic behaviour

    Directory of Open Access Journals (Sweden)

    M Battistelli

    2009-06-01

    Full Text Available Rhodiola rosea L. (Crassulaceae is a plant that lives at high altitude in Europe and Asia, usually used for its high capacity to increase the organism resistance to different stress conditions. Although a few international literature supports these effects, today R. rosea has become a common component of many dietary supplements also in the Western world. The aim of the present study was to investigate the effect of the R. rosea roots aqueous extract on in vitro human erythrocytes exposed to hypochlorous acid (HOCl- oxidative stress. Several damages occur in human erythrocytes exposed in vitro to HOCl, among these membrane protein and lipid modifications, shifting from the discocyte shape to the echinocyte one, and determining lysis ultimately. Therefore, in the present work, the evaluation of the antioxidant capacity of the Rhodiola extract has been carried out by means of scanning electron microscopy and of hemolytic behaviour on human erythrocytes exposed to HOCl in the presence of increasing doses of the aqueous extract in different experimental environments (co-incubation and subsequent incubations. The results obtained are consistent with a significative protection of the extract in presence of the oxidative agent, but a cautionary note emerges from the analysis of the data related to the cell exposition to the plant extract in the absence of any induced oxidative stress. In fact, the addition to erythrocyte of high doses of R. rosea extract always determines severe alterations of the cell shape.

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

    International Nuclear Information System (INIS)

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

  11. Effects of Colistin on Surface Ultrastructure and Nanomechanics of Pseudomonas aeruginosa Cells

    DEFF Research Database (Denmark)

    Mortensen, Ninell Pollas; Fowlkes, Jason D.; Sullivan, Claretta J.;

    2009-01-01

    Chronic lung infections in cystic fibrosis patients are primarily caused by Pseudomonas aeruginosa. Though difficult to counteract effectively, colistin, an antimicrobial peptide, is proving useful. However, the exact mechanism of action of colistin is not fully understood. In this study, atomic...... force microscopy (AFM) was used to evaluate, in a liquid environment, the changes in P. aeruginosa morphology and nanomechanical properties due to exposure to colistin. The results of this work revealed that after 1 h of colistin exposure the ratio of individual bacteria to those found to be arrested in...... the process of division changed from 1.9 to 0.4 and the length of the cells decreased significantly. Morphologically, it was observed that the bacterial surface changed from a smooth to a wrinkled phenotype after 3 h exposure to colistin. Nanomechanically, in untreated bacteria, the cantilever...

  12. Dynamic distribution of TTK in HeLa cells: insights from an ultrastructural study

    Institute of Scientific and Technical Information of China (English)

    ZHEN DOU; AKIRA SAWAGECHI; JIE ZHANG; HONG LUO; LAWRENCE BRAKO; XUE BIAO YAO

    2003-01-01

    Entry into mitosis is driven by signaling cascades of mitotic kinases.Our recent studies show that TTK,a kinetochore-associated protein kinase,interacts with CENP-E,a mitotic kinesin located to corona fiber ofkinetochore.Using immunoelectron microscopy,here we show that TTK is present at the nuclear pore adjacent complex of interphase HeLa cells.Upon nuclear envelope fragmentation,TTK targets to the outermostregion of the developing kinetochores ofmonoorient chromosome as well as to spindle poles.After stable attachment,throughout chromosome congression,TTK is a constituent of the corona fibers,extending up to 90 nm away from the kinetochore outer plate.Upon metaphase alignment,TTK departs from the kinetochore and migrates toward the centrosomes.Taken together,this evidence strongly supports a model in which TTK functions in spindle checkpoint signaling cascades at both kinetochore and centrosome.

  13. Comparison of cell wall proteins of Saccharomyces cerevisiae as anchors for cell surface expression of heterologous proteins.

    OpenAIRE

    van der Vaart, J. M.; te Biesebeke, R; Chapman, J.W.; Toschka, H Y; Klis, F M; Verrips, C. T.

    1997-01-01

    The carboxyl-terminal regions of five cell wall proteins (Cwp1p, Cwp2p, Ag alpha 1p, Tip1p, and Flo1p) and three potential cell wall proteins (Sed1p, YCR89w, and Tir1p) all proved capable of immobilizing alpha-galactosidase in the cell wall of Saccharomyces cerevisiae. The fraction of the total amount of fusion protein that was localized to the cell wall varied depending on the anchor domain used. The highest proportion of cell wall incorporation was achieved with Cwp2p, Ag alpha 1p, or Sed1p...

  14. Determination of the pore size of cell walls of living plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Carpita, N.; Sabularse, D.; Montezinos, D.; Delmer, D.P.

    1979-09-14

    The limiting diameter of pores in the walls of living plant cells through which molecules can freely pass has been determined by a solute exclusion technique to be 35 to 38 angstroms for hair cells of Raphanus sativus roots and fibers of Gossypium hirsutum, 38 to 40 angstroms for cultured cells of Acer pseudoplatanus, and 45 to 52 angstroms for isolated palisade parenchyma cells of the leaves of Xanthium strumarium and Commelina communis. These results indicate that molecules with diameters larger than these pores would be restricted in their ability to penetrate such a cell wall, and that such a wall may represent a more significant barrier to cellular communication than has been previously assumed.

  15. GABA agonist induced changes in ultrastructure and GABA receptor expression in cerebellar granule cells is linked to hyperpolarization of the neurons

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, Gert Helge; Schousboe, A

    1990-01-01

    GABA has been shown to exert a neurotrophic like activity by enhancing the morphological and functional maturation of neurons. Mechanisms involved in this effect of GABA are largely unknown but since GABA has been shown to mediate a hyperpolarizing action on neurons it can be assumed that this...... action might be important. In order to investigate this possibility, the ability to mimic the trophic actions of GABA of different agents known to influence the membrane potential or the GABA gated chloride channels was studied. Hence, GABA receptor expression as well as the ultrastructure of cerebellar...... granule cells were monitored after exposure of the cells in culture to either bromide, valinomycin or picrotoxin. It was found that cells which at early developmental stages (4 days in culture) were exposed to bromide or valinomycin expressed low affinity GABA receptors similar to cells treated with the...

  16. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  17. Rhizobium sp. Degradation of Legume Root Hair Cell Wall at the Site of Infection Thread Origin

    OpenAIRE

    Ridge, Robert W.; Rolfe, Barry G.

    1985-01-01

    Using a new microinoculation technique, we demonstrated that penetration of Rhizobium sp. into the host root hair cell occurs at 20 to 22 h after inoculation. It did this by dissolving the cell wall maxtrix, leaving a layer of depolymerized wall microfibrils. Colony growth pressure “stretched” the weakened wall, forming a bulge into an interfacial zone between the wall and plasmalemma. At the same time vesicular bodies, similar to plasmalemmasomes, accumulated at the penetration site in a man...

  18. Proteomic Analysis to Identify Tightly-Bound Cell Wall Protein in Rice Calli

    OpenAIRE

    Cho, Won Kyong; Hyun, Tae Kyung; Kumar, Dhinesh; Rim, Yeonggil; Chen, Xiong Yan; Jo, Yeonhwa; Kim, Suwha; Lee, Keun Woo; Park, Zee-Yong; Lucas, William J.; Kim, Jae-Yean

    2015-01-01

    Rice is a model plant widely used for basic and applied research programs. Plant cell wall proteins play key roles in a broad range of biological processes. However, presently, knowledge on the rice cell wall proteome is rudimentary in nature. In the present study, the tightly-bound cell wall proteome of rice callus cultured cells using sequential extraction protocols was developed using mass spectrometry and bioinformatics methods, leading to the identification of 1568 candidate proteins. Ba...

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

    OpenAIRE

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

    2010-01-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the s...

  20. Perpetual production of hair cells and maturational changes in hair cell ultrastructure accompany postembryonic growth in an amphibian ear.

    OpenAIRE

    Corwin, J T

    1985-01-01

    Sensory hair cells are produced in the ears of birds and mammals only during early development, so that a programmed termination of hair cell proliferation leaves adult birds and mammals susceptible to irreversible deafness and balance disorders. This study reports that this is not an inherent feature of hair cells and is not shared through all the vertebrate classes. In toads (Bufo marinus) hair cells accumulate throughout life, increasing in the sacculus from approximately 400 cells at meta...

  1. The effects of gamma irradiation and calcium treatment on the ultrastructure of apples and pears

    International Nuclear Information System (INIS)

    The post-storage quality of fruits depends on the ultrastructure of the outer tissues and on the fruit mineral composition (mostly on calcium). Pectins and their bonds with calcium play a central role in the tissues during ripening. During senescence the middle lamella disappears from the cell walls, the fruits become soft and cell wall reticulation can be seen. There are changes within the cells too; plasmalemma separates from the wall, tonoplast from the cytoplasm, and plastids, mitochondria and nuclei are disorganized. The ultrastructure of the skin and flesh of apples and pears were studied as a function of treatments (calcium, irradiation, calcium combined with irradiation), storage time and varieties. The texture and calcium content of the different parts of fruits were determined. We established that low dose (1 kGy) irradiation induced softening in the fruit, dissolution of middle lamellae, wrinkling of cell membranes which generally remained intact, and retention of starch by plastids of the skin. Calcium treatment preserved the cell membranes and middle lamellae. The combined treatment preserved the cell compartments the best (with a lot of starch in the plastids; the cytopolasm remained essentially unchanged). At the same time this treatment could not prevent the breakdown of the middle lamellae in irradiated tissue

  2. Plumbagin, a plant-derived naphthoquinone metabolite induces mitochondria mediated apoptosis-like cell death in Leishmania donovani: an ultrastructural and physiological study.

    Science.gov (United States)

    Awasthi, Bhanu Priya; Kathuria, Manoj; Pant, Garima; Kumari, Neema; Mitra, Kalyan

    2016-08-01

    Naphthoquinones are known to exhibit a broad range of biological activities against microbes, cancer and parasitic diseases and have been widely used in Indian traditional medicine. Plumbagin is a plant-derived naphthoquinone metabolite (5-hydroxy-2-methyl-1,4-naphthoquinone) reported to inhibit trypanothione reductase, the principal enzyme and a validated drug target involved in detoxification of oxidative stress in Leishmania. Here, we report the mechanistic aspects of cell death induced by plumbagin including physiological effects in the promastigote form and ultrastructural alterations in both promastigote and amastigote forms of Leishmania donovani which till now remained largely unknown. Our observations show that oxidative stress induced by plumbagin resulted in depolarization of the mitochondrial membrane, depletion in ATP levels, elevation of cytosolic calcium, increase in caspase 3/7-like protease activity and lipid peroxidation in promastigotes. Apoptosis-like cell death induction post plumbagin treatment was confirmed by biochemical assays like Annexin V/FITC staining, TUNEL as well as morphological and ultrastructural studies. These findings collectively highlight the mode of action and importance of oxidative stress inducing agents in effectively killing both forms of the Leishmania parasite and opens up the possibility of exploring plumbagin and its derivatives as promising candidates in the chemotherapy of Leishmaniasis. PMID:27315817

  3. The effect of AgNO{sub 3} on the bioenergetic processes and the ultrastructure of Chlorella and Dunaliella cells exposed to different saline conditions

    Energy Technology Data Exchange (ETDEWEB)

    Loseva, N.L. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation)]. E-mail: loseva@mail.knc.ru; Alyabyev, A.Ju. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation); Gordon, L.Kh. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation); Andreyeva, I.N. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation); Kolesnikov, O.P. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation); Ponomareva, A.A. [Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111 (Russian Federation); Kemp, R.B. [Institute of Biological Sciences, Edward Llwyd Building, Penglais, University of Wales, Aberystwyth SY23 3DA (United Kingdom)

    2007-06-25

    The effect of AgNO{sub 3}, an inhibitor of the H{sup +} pump in the plasma membrane, on the bioenergetic processes and on the ultrastructure of the microalgae Chlorella vulgaris (salt sensitive) and Dunaliella maritima (salt resistant) was examined under varying salt concentrations. Differences between them were observed in changes of the cellular energy metabolism depending on their salt sensitivity and the inhibition of the H{sup +} pump activity. A decrease was observed in the rates of heat production (about 45%), O{sub 2} uptake (greater than 40-50% of the control) and particularly photosynthesis (more than 80%) in Chlorella cells under the simultaneous action of NaCl and AgNO{sub 3}. Dunaliella cells showed small to moderate rate increases for heat production (less than 7%), O{sub 2} uptake (10-15%) and O{sub 2} evolution (40%) in higher salt concentrations and under the action of AgNO{sub 3}. The production of active oxygen species was studied as an early unspecific response of microalgal cells to possible unfavorable conditions, including salt stress. The amount of superoxide formed by the Dunaliella cells was higher than that by the Chlorella cells. However, Ag{sup +} ions increased the generation rate of superoxide radicals considerably in both Chlorella and Dunaliella cells. The electron microscopy showed that changes of the algal ultrastructure of cells exposed to the action of Ag{sup +} ions were connected with the observed physiological changes and to a large extent with the alteration of the bioenergetic processes in them.

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

    OpenAIRE

    Laar, van, J.A.

    2000-01-01

    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...

  5. 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

    2015-01-01

    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.

  6. Ultrastructure of potato tubers formed in microgravity under controlled environmental conditions

    Science.gov (United States)

    Cook, Martha E.; Croxdale, Judith G.; Tibbitts, T. W. (Principal Investigator)

    2003-01-01

    Previous spaceflight reports attribute changes in plant ultrastructure to microgravity, but it was thought that the changes might result from growth in uncontrolled environments during spaceflight. To test this possibility, potato explants were examined (a leaf, axillary bud, and small stem segment) grown in the ASTROCULTURETM plant growth unit, which provided a controlled environment. During the 16 d flight of space shuttle Columbia (STS-73), the axillary bud of each explant developed into a mature tuber. Upon return to Earth, tuber slices were examined by transmission electron microscopy. Results showed that the cell ultrastructure of flight-grown tubers could not be distinguished from that of tuber cells grown in the same growth unit on the ground. No differences were observed in cellular features such as protein crystals, plastids with starch grains, mitochondria, rough ER, or plasmodesmata. Cell wall structure, including underlying microtubules, was typical of ground-grown plants. Because cell walls of tubers formed in space were not required to provide support against the force due to gravity, it was hypothesized that these walls might exhibit differences in wall components as compared with walls formed in Earth-grown tubers. Wall components were immunolocalized at the TEM level using monoclonal antibodies JIM 5 and JIM 7, which recognize epitopes of pectins, molecules thought to contribute to wall rigidity and cell adhesion. No difference in presence, abundance or distribution of these pectin epitopes was seen between space- and Earth-grown tubers. This evidence indicates that for the parameters studied, microgravity does not affect the cellular structure of plants grown under controlled environmental conditions.

  7. Ultrastructure of ovarian follicular epithelium of the amazonian fish Pseudotylosurus microps (Gunther (Teleostei, Belonidae: I. the follicular cells cycle of development

    Directory of Open Access Journals (Sweden)

    Carminda da Cruz-Landim

    2001-03-01

    Full Text Available The present paper deals with the changes on ultrastructural features of the follicular cells along the growth of the oocyte of Pseudotylosurus microps (Gunther, 1868. The epithelium pass from single squamous to pseudostratified and finally cylindric. Remarkable are the changes in the nuclear shapes, the increasing amount of rough endoplasmic reticulum and the formation of large lipid deposits in the follicular cells by the end of vitellogenic phase. Very peculiar intercellular deposits forms between the perinucleolar and vitellogenic phase of oocyte maturation. Although largely referred to in the specialized literature, our attempts to correlate the follicular cells changes with the formation of the oocyte envelopes or even with an endocrine function are not supported by conclusive evidences in the present paper.

  8. Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, J. [Departamento de Microbiologia e Inmunologia Veterinaria, Universidad Federal Rural de Rio de Janeiro (UFRRJ) (Brazil); Cavaglieri, L., E-mail: lcavaglieri@arnet.com.a [Departamento de Microbiologia e Inmunologia, Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Cordoba (Argentina); Member of Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CIC-CONICET) (Argentina); Vital, H. [Centro Tecnologico do Exercito (CTEx), Secao de Defesa Nuclear, Rio de Janeiro (Brazil); Cristofolini, A.; Merkis, C. [Departamento de Microscopia Electronica, Universidad Nacional de Rio Cuarto. Ruta 36 km 601 (5800) Rio Cuarto (Argentina); Astoreca, A. [Departamento de Microbiologia e Inmunologia, Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Cordoba (Argentina); Member of Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CIC-CONICET) (Argentina); Orlando, J.; Caru, M. [Departamento de Ciencias Ecologicas, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Dalcero, A. [Departamento de Microbiologia e Inmunologia, Universidad Nacional de Rio Cuarto (UNRC), Rio Cuarto, Cordoba (Argentina); Member of Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CIC-CONICET) (Argentina); Rosa, C.A.R. [Departamento de Microbiologia e Inmunologia Veterinaria, Universidad Federal Rural de Rio de Janeiro (UFRRJ) (Brazil); Member of Consejo Nacional de Pesquisas (CNPq) (Brazil)

    2011-05-15

    The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B{sub 1} and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

  9. 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

    2009-01-01

    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.

  10. Area Expansivity Moduli of Regenerating Plant Protoplast Cell Walls Exposed to Shear Flows

    Science.gov (United States)

    Fujimura, Yuu; Iino, Masaaki; Watanabe, Ugai

    2005-05-01

    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.

  11. Starting to Gel: How Arabidopsis Seed Coat Epidermal Cells Produce Specialized Secondary Cell Walls

    Directory of Open Access Journals (Sweden)

    Cătălin Voiniciuc

    2015-02-01

    Full Text Available For more than a decade, the Arabidopsis seed coat epidermis (SCE has been used as a model system to study the synthesis, secretion and modification of cell wall polysaccharides, particularly pectin. Our detailed re-evaluation of available biochemical data highlights that Arabidopsis seed mucilage is more than just pectin. Typical secondary wall polymers such as xylans and heteromannans are also present in mucilage. Despite their low abundance, these components appear to play essential roles in controlling mucilage properties, and should be further investigated. We also provide a comprehensive community resource by re-assessing the mucilage phenotypes of almost 20 mutants using the same conditions. We conduct an in-depth functional evaluation of all the SCE genes described in the literature and propose a revised model for mucilage production. Further investigation of SCE cells will improve our understanding of plant cell walls.

  12. Ultrastructural Islet Study of Early Fibrosis in the Ren2 Rat Model of Hypertension. Emerging Role of the Islet Pancreatic Pericyte-Stellate Cell

    Directory of Open Access Journals (Sweden)

    Melvin R Hayden

    2007-11-01

    Full Text Available Context Type 2 diabetes mellitus is a multifactorial disease with polygenic and environmental stressors resulting in multiple metabolic toxicities and islet oxidative stress. We have integrated the role of the islet reninangiotensin system (RAS in the pathogenesis of early islet fibrosis utilizing the transgenic (mRen227 rodent model of hypertension and tissue RAS overexpression. Objective The Ren2 pancreatic islet tissue was evaluated with transmission electron microscopy to study both early cellular and extracellular matrix remodeling. Animals Four 9- to 10-week-old male Ren2 untreated models and four Sprague Dawley sex and age matched controls were used. Design Ultrastructural study to compare pancreatic islet tissue. Main outcome measures Only qualitative and observational transmission electron microscopy findings are reported. Results Major remodeling differences in the Ren2 model were found to be located within the islet exocrine interface, including deposition of early fibrillar-banded collagen (fibrosis and cellular remodeling of the pericyte suggesting proliferation, migration, hypertrophy and activation as compared to the Sprague Dawley controls. Conclusion This study points to the possibility of the pericyte cell being one of many contributors to the fibrogenic pool of cells important for peri-islet fibrosis as a result of excess angiotensin II at the local tissue level in the Ren2 model. These findings suggest that the pericyte may be capable of differentiating into the pancreatic stellate cell. This islet ultrastructure study supports the notion that pericyte cells could be the link between islet vascular oxidative stress and peri-islet fibrosis. Pericyte-endothelialpancreatic stellate cell associations and morphology are discussed.

  13. Elucidation of the chemical fine structure of polysaccharides from soybean and maize kernel cell walls

    OpenAIRE

    Huisman, M.M.H.

    2000-01-01

    The subject of this thesis was the elucidation of the chemical fine structure of polysaccharides from cell walls of soybean and maize kernel. The two species investigated represent different taxonomic groups, soybean belonging to the dicotyledonous and maize to the monocotyledonous plants. Besides representing the most important structures present in cell wall material, these raw materials are of great importance in food and feed industry.The characterisation of the soybean cell wall polysacc...

  14. In vivo cell wall loosening by hydroxyl radicals during cress seed germination and elongation growth

    OpenAIRE

    Müller, Kerstin; Linkies, Ada; Vreeburg, Robert A. M.; Fry, Stephen C; Krieger-Liszkay, Anja; Leubner-Metzger, Gerhard

    2009-01-01

    Loosening of cell walls is an important developmental process in key stages of plant life cycles, 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 seedling growth. We used electron paramagnetic resonance (EPR)-spectroscopy to show that •OH is generated in the cell wall during radicle elongation and weakening of the endosperm of cress (Lepidium sativ...

  15. Cell wall synthesis and initiation of deoxyribonucleic acid replication in Bacillus subtilis.

    OpenAIRE

    Sandler, N.; Keynan, A

    1981-01-01

    We have observed a connection between cell wall synthesis and the initiation of chromosome replication in Bacillus subtilis. Initiation of chromosome replication was prevented in synchronous cultures in the presence of the cell wall synthesis inhibitor vancomycin. When vancomycin was added to the cultures after initiation of chromosome replication, one round of replication was completed but no reinitiation occurred. Similar results were obtained when cell wall synthesis was inhibited by risto...

  16. Cell wall sorting signals in surface proteins of gram-positive bacteria.

    OpenAIRE

    Schneewind, O; Mihaylova-Petkov, D; Model, P

    1993-01-01

    Staphylococcal protein A is anchored to the cell wall, a unique cellular compartment of Gram-positive bacteria. The sorting signal sufficient for cell wall anchoring consists of an LPXTG motif, a C-terminal hydrophobic domain and a charged tail. Homologous sequences are found in many surface proteins of Gram-positive bacteria and we explored the universality of these sequences to serve as cell wall sorting signals. We show that several signals are able to anchor fusion proteins to the staphyl...

  17. Diversity of beetle genes encoding novel plant cell wall degrading enzymes

    OpenAIRE

    Pauchet, Y.; Wilkinson, P.; Chauhan, R.; Ffrench-Constant, R.

    2010-01-01

    Plant cell walls are a heterogeneous mixture of polysaccharides and proteins that require a range of different enzymes to degrade them. Plant cell walls are also the primary source of cellulose, the most abundant and useful biopolymer on the planet. Plant cell wall degrading enzymes (PCWDEs) are therefore important in a wide range of biotechnological processes from the production of biofuels and food to waste processing. However, despite the fact that the last common ancestor of all deuterost...

  18. Two cationic peroxidases from cell walls of Araucaria araucana seeds.

    Science.gov (United States)

    Riquelme, A; Cardemil, L

    1995-05-01

    We have previously reported the purification and partial characterization of two cationic peroxidases from the cell walls of seeds and seedlings of the South American conifer, Araucaria araucana. In this work, we have studied the amino acid composition and NH2-terminal sequences of both enzymes. We also compare the data obtained from these analyses with those reported for other plant peroxidases. The two peroxidases are similar in their amino acid compositions. Both are particularly rich in glycine, which comprises more than 30% of the amino acid residues. The content of serine is also high, ca 17%. The two enzymes are different in their content of arginine, alanine, valine, phenylalanine and threonine. Both peroxidases have identical NH2-terminal sequences, indicating that the two proteins are genetically related and probably are isoforms of the same kind of peroxidase. The amino acid composition and NH2-terminal sequence analyses showed marked differences from the cationic peroxidases from turnip and horseradish. PMID:7786490

  19. Single Wall Carbon Nanotube-polymer Solar Cells

    Science.gov (United States)

    Bailey, Sheila G.; Castro, Stephanie L.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2005-01-01

    Investigation of single wall carbon nanotube (SWNT)-polymer solar cells has been conducted towards developing alternative lightweight, flexible devices for space power applications. Photovoltaic devices were constructed with regioregular poly(3-octylthiophene)-(P3OT) and purified, >95% w/w, laser-generated SWNTs. The P3OT composites were deposited on ITO-coated polyethylene terapthalate (PET) and I-V characterization was performed under simulated AM0 illumination. Fabricated devices for the 1.0% w/w SWNT-P3OT composites showed a photoresponse with an open-circuit voltage (V(sub oc)) of 0.98 V and a short-circuit current density (I(sub sc)) of 0.12 mA/sq cm. Optimization of carrier transport within these novel photovoltaic systems is proposed, specifically development of nanostructure-SWNT complexes to enhance exciton dissociation.

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

    Science.gov (United States)

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

    2016-07-01

    Lead, one of the most abundant and hazardous trace metals affecting living organisms, has been commonly detected in plant cell walls including some tolerant plants, mining ecotypes and hyperaccumulators. We have previously shown that in tip growing Funaria sp. protonemata cell wall is remodeled in response to lead by formation of thickenings rich in low-methylesterified pectins (pectin epitope JIM5 - JIM5-P) able to bind metal ions, which accumulate large amounts of Pb. Hence, it leads to the increase of cell wall capacity for Pb compartmentalization. Here we show that diverse plant species belonging to different phyla (Arabidopsis, hybrid aspen, star duckweed), form similar cell wall thickenings in response to Pb. These thickenings are formed in tip growing cells such as the root hairs, and in diffuse growing cells such as meristematic and root cap columella cells of root apices in hybrid aspen and Arabidopsis and in mesophyll cells in star duckweed fronds. Notably, all analyzed cell wall thickenings were abundant in JIM5-P and accumulated high amounts of Pb. In addition, the co-localization of JIM5-P and Pb commonly occurred in these cells. Hence, cell wall thickenings formed the extra compartment for Pb accumulation. In this way plant cells increased cell wall capacity for compartmentalization of this toxic metal, protecting protoplast from its toxicity. As cell wall thickenings occurred in diverse plant species and cell types differing in the type of growth we may conclude that pectinous cell wall thickenings formation is a widespread defense strategy of plants to cope with Pb. Moreover, detection of natural defense strategy, increasing plant cell walls capacity for metal accumulation, reveals a promising direction for enhancing plant efficiency in phytoremediation. PMID:27107260

  1. In-vitro fermentability of cell walls as influenced by lignin composition and cross-linking.

    Science.gov (United States)

    We assessed how diverse modifications in lignin composition and reductions in ferulate-lignin cross-linking influence the degradability of cell walls. Cell walls from nonlignified maize cell suspensions were artificially lignified with varying ratios of normal monolignols (coniferyl and sinapyl alco...

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

    Energy Technology Data Exchange (ETDEWEB)

    Carpita, Nicholas C.

    2001-10-18

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

  3. Cell wall antibiotics provoke accumulation of anchored mCherry in the cross wall of Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Wenqi Yu

    Full Text Available A fluorescence microscopy method to directly follow the localization of defined proteins in Staphylococcus was hampered by the unstable fluorescence of fluorescent proteins. Here, we constructed plasmid (pCX encoded red fluorescence (RF mCherry (mCh hybrids, namely mCh-cyto (no signal peptide and no sorting sequence, mCh-sec (with signal peptide, and mCh-cw (with signal peptide and cell wall sorting sequence. The S. aureus clones targeted mCh-fusion proteins into the cytosol, the supernatant and the cell envelope respectively; in all cases mCherry exhibited bright fluorescence. In staphylococci two types of signal peptides (SP can be distinguished: the +YSIRK motif SP(lip and the -YSIRK motif SP(sasF. mCh-hybrids supplied with the +YSIRK motif SP(lip were always expressed higher than those with -YSIRK motif SP(sasF. To study the location of the anchoring process and also the influence of SP type, mCh-cw was supplied on the one hand with +YSIRK motif (mCh-cw1 and the other hand with -YSIRK motif (mCh-cw2. MCh-cw1 preferentially localized at the cross wall, while mCh-cw2 preferentially localized at the peripheral wall. Interestingly, when treated with sub-lethal concentrations of penicillin or moenomycin, both mCh-cw1 and mCh-cw2 were concentrated at the cross wall. The shift from the peripheral wall to the cross wall required Sortase A (SrtA, as in the srtA mutant this effect was blunted. The effect is most likely due to antibiotic mediated increase of free anchoring sites (Lipid II at the cross wall, the substrate of SrtA, leading to a preferential incorporation of anchored proteins at the cross wall.

  4. Principles of bacterial cell-size determination revealed by cell wall synthesis perturbations

    OpenAIRE

    Carolina Tropini; Timothy K. Lee; Jen Hsin; Samantha M. Desmarais; Tristan Ursell; Russell D. Monds; Kerwyn Casey Huang

    2014-01-01

    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 cyto...

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

    Directory of Open Access Journals (Sweden)

    Mediesse Kengne Francine

    2014-12-01

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

  6. 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

    2014-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

    2009-02-16

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

  8. A 3-D Model of a Perennial Ryegrass Primary Cell Wall and Its Enzymatic Degradation

    OpenAIRE

    Indrakumar Vetharaniam; Kelly, William J.; Graeme T. Attwood; Harris, Philip J.

    2014-01-01

    We have developed a novel 3-D, agent-based model of cell-wall digestion to improve our understanding of ruminal cell-wall digestion. It offers a capability to study cell walls and their enzymatic modification, by providing a representation of cellulose microfibrils and non-cellulosic polysaccharides and by simulating their spatial and catalytic interactions with enzymes. One can vary cell-wall composition and the types and numbers of enzyme molecules, allowing the model to be applied to a ran...

  9. Igf1r+/CD34+ immature ICC are putative adult progenitor cells, identified ultrastructurally as fibroblast-like ICC in Ws/Ws rat colon

    DEFF Research Database (Denmark)

    Wang, X Y; Albertí, E; White, E J; Mikkelsen, Hanne Birte; Larsen, Jytte Overgaard; Jiménez, M; Huizinga, J D

    (ICC-AP) were significantly decreased and ICC located at the submuscular plexus and intramuscular ICC were rarely observed based on immunohistochemistry and electron microscopy. Ultrastructural investigations revealed that there was no overall loss of all types of interstitial cells combined. Where...... loss of ICC was observed, a marked increase in fibroblast-like ICC (FL-ICC) was found at the level of AP. Immunoelectron microscopy proved FL-ICC to be c-Kit(-) but gap junction coupled to each other and to c-Kit(+) ICC; they were associated with enteric nerves and occupied space normally occupied by...... ICC in the wild-type rat colon, suggesting them to be immature ICC. In addition, a marked increase in immunoreactivity for insulin-like growth factor 1 receptor (Igf1r) occurred, co-localized with CD34 but not with c-Kit. A significantly higher number of Igf1r(+)/CD34(+) cells were found in Ws...

  10. A phosphorylated pseudokinase complex controls cell wall synthesis in mycobacteria.

    Science.gov (United States)

    Gee, Christine L; Papavinasasundaram, Kadamba G; Blair, Sloane R; Baer, Christina E; Falick, Arnold M; King, David S; Griffin, Jennifer E; Venghatakrishnan, Harene; Zukauskas, Andrew; Wei, Jun-Rong; Dhiman, Rakesh K; Crick, Dean C; Rubin, Eric J; Sassetti, Christopher M; Alber, Tom

    2012-01-24

    Prokaryotic cell wall biosynthesis is coordinated with cell growth and division, but the mechanisms regulating this dynamic process remain obscure. Here, we describe a phosphorylation-dependent regulatory complex that controls peptidoglycan (PG) biosynthesis in Mycobacterium tuberculosis. We found that PknB, a PG-responsive Ser-Thr protein kinase (STPK), initiates complex assembly by phosphorylating a kinase-like domain in the essential PG biosynthetic protein, MviN. This domain was structurally diverged from active kinases and did not mediate phosphotransfer. Threonine phosphorylation of the pseudokinase domain recruited the FhaA protein through its forkhead-associated (FHA) domain. The crystal structure of this phosphorylated pseudokinase-FHA domain complex revealed the basis of FHA domain recognition, which included unexpected contacts distal to the phosphorylated threonine. Conditional degradation of these proteins in mycobacteria demonstrated that MviN was essential for growth and PG biosynthesis and that FhaA regulated these processes at the cell poles and septum. Controlling this spatially localized PG regulatory complex is only one of several cellular roles ascribed to PknB, suggesting that the capacity to coordinate signaling across multiple processes is an important feature conserved between eukaryotic and prokaryotic STPK networks. PMID:22275220

  11. CELL-WALL GROWTH AND PROTEIN SECRETION IN FUNGI

    NARCIS (Netherlands)

    SIETSMA, JH; WOSTEN, HAB; WESSELS, JGH

    1995-01-01

    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

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

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

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

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

    Directory of Open Access Journals (Sweden)

    António Rego

    2014-08-01

    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.

  14. Ultra-estrutura dos mastócitos de diferentes tipos histológicos de mastocitoma em cães Mast cell ultrastructure in different types of canine mast cell tumor

    Directory of Open Access Journals (Sweden)

    F.A.R. Sueiro

    2002-06-01

    Full Text Available Este trabalho teve por objetivo estudar as diferenças ultraestruturais de mastócitos neoplásicos de diferentes tipos histológicos de mastocitoma em cães, usando microscopia eletrônica de transmissão Os resultados mostraram que o núcleo e os grânulos citoplasmáticos são as estruturas mais indicadas para se avaliar o grau de anaplasia celular e o estádio de indiferenciação do tumor.The objective of this work was study the ultrastructural differences among the different histologic types of mast cell tumors in dogs collected in vivo. The ultrastructural analyses showed that the nuclei and cytoplasmic granules characteristics are the best structures to be appointed on evaluating the undifferentiation stage of this tumor.

  15. The Cell Wall Protein Ecm33 of Candida albicans is Involved in Chronological Life Span, Morphogenesis, Cell Wall Regeneration, Stress Tolerance, and Host–Cell Interaction

    Science.gov (United States)

    Gil-Bona, Ana; Reales-Calderon, Jose A.; Parra-Giraldo, Claudia M.; Martinez-Lopez, Raquel; Monteoliva, Lucia; Gil, Concha

    2016-01-01

    Ecm33 is a glycosylphosphatidylinositol-anchored protein in the human pathogen Candida albicans. This protein is known to be involved in fungal cell wall integrity (CWI) and is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis, but its function remains unknown. In this work, several phenotypic analyses of the C. albicans ecm33/ecm33 mutant (RML2U) were performed. We observed that RML2U displays the inability of protoplast to regenerate the cell wall, activation of the CWI pathway, hypersensitivity to temperature, osmotic and oxidative stresses and a shortened chronological lifespan. During the exponential and stationary culture phases, nuclear and actin staining revealed the possible arrest of the cell cycle in RML2U cells. Interestingly, a “veil growth,” never previously described in C. albicans, was serendipitously observed under static stationary cells. The cells that formed this structure were also observed in cornmeal liquid cultures. These cells are giant, round cells, without DNA, and contain large vacuoles, similar to autophagic cells observed in other fungi. Furthermore, RML2U was phagocytozed more than the wild-type strain by macrophages at earlier time points, but the damage caused to the mouse cells was less than with the wild-type strain. Additionally, the percentage of RML2U apoptotic cells after interaction with macrophages was fewer than in the wild-type strain. PMID:26870022

  16. Delineation of six species of the primitive algal genus Glaucocystis based on in situ ultrastructural characteristics.

    Science.gov (United States)

    Takahashi, Toshiyuki; Nishida, Tomoki; Tuji, Akihiro; Saito, Chieko; Matsuzaki, Ryo; Sato, Mayuko; Toyooka, Kiminori; Yasuda, Hidehiro; Nozaki, Hisayoshi

    2016-01-01

    The field of microbiology was established in the 17(th) century upon the discovery of microorganisms by Antonie van Leeuwenhoek using a single-lens microscope. Now, the detailed ultrastructures of microorganisms can be elucidated in situ using three-dimensional electron microscopy. Since the availability of electron microscopy, the taxonomy of microscopic organisms has entered a new era. Here, we established a new taxonomic system of the primitive algal genus Glaucocystis (Glaucophyta) using a new-generation electron microscopic methodology: ultra-high-voltage electron microscopy (UHVEM) and field-emission scanning electron microscopy (FE-SEM). Various globally distributed Glaucocystis strains were delineated into six species, based on differences in in situ ultrastructural features of the protoplast periphery under UHVEM tomography and in the mother cell wall by FE-SEM, as well as differences in the light microscopic characteristics and molecular phylogenetic results. The present work on Glaucocystis provides a model case of new-generation taxonomy. PMID:27383831

  17. Glycosylation of Candida albicans cell wall proteins is critical for induction of innate immune responses and apoptosis of epithelial cells.

    OpenAIRE

    Wagener, Jeanette; Weindl, Günther; de Groot, Piet W. J.; de Boer, Albert D.; Kaesler, Susanne; Thavaraj, Selvam; Bader, Oliver; Mailänder-Sanchez, Daniela; Borelli, Claudia; Weig, Michael; Biedermann, Tilo; Naglik, Julian R.; Korting, Hans Christian; Schaller, Martin

    2012-01-01

    C. albicans is one of the most common fungal pathogen of humans, causing local and superficial mucosal infections in immunocompromised individuals. Given that the key structure mediating host-C. albicans interactions is the fungal cell wall, we aimed to identify features of the cell wall inducing epithelial responses and be associated with fungal pathogenesis. We demonstrate here the importance of cell wall protein glycosylation in epithelial immune activation with a predominant role for the ...

  18. Restrictive glycosylphosphatidylinositol anchor synthesis in cwh6/gpi3 yeast cells causes aberrant biogenesis of cell wall proteins.

    OpenAIRE

    Vossen, J.H.; Müller, W. H.; Lipke, P N; Klis, F. M.

    1997-01-01

    We previously reported that the defects in the Saccharomyces cerevisiae cwh6 Calcofluor white-hypersensitive cell wall mutant are caused by a mutation in SPT14/GPI3, a gene involved in glycosylphosphatidylinositol (GPI) anchor biosynthesis. Here we describe the effect of cwh6/spt14/gpi3 on the biogenesis of cell wall proteins. It was found that the release of precursors of cell wall proteins from the endoplasmic reticulum (ER) was retarded. This was accompanied by proliferation of ER structur...

  19. NAC-MYB-based transcriptional regulation of secondary cell wall biosynthesis in land plants

    OpenAIRE

    Nakano, Yoshimi; Yamaguchi, Masatoshi; Endo, Hitoshi; Rejab, Nur Ardiyana; Ohtani, Misato

    2015-01-01

    Plant cells biosynthesize primary cell walls (PCW) in all cells and produce secondary cell walls (SCWs) in specific cell types that conduct water and/or provide mechanical support, such as xylem vessels and fibers. The characteristic mechanical stiffness, chemical recalcitrance, and hydrophobic nature of SCWs result from the organization of SCW-specific biopolymers, i.e., highly ordered cellulose, hemicellulose, and lignin. Synthesis of these SCW-specific biopolymers requires SCW-specific enz...

  20. 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

    2013-01-01

    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.

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

    International Nuclear Information System (INIS)

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

  2. FINITE ELEMENT ANALYSIS OF THE FATIGUE BEHAVIOR OF WOOD FIBER CELL WALLS

    Directory of Open Access Journals (Sweden)

    Phichit Somboon

    2008-11-01

    Full Text Available The fatigue behavior of the wood fiber cell wall under mechanical treatment in refining was simulated dynamically using a finite element method. The effect of the amplitude and frequency of impacts on the mechanical breakdown of the fiber wall structure was examined. The proposed model of the fiber cell wall was constructed from elementary microfibrils in various orientations embedded in isotropic lignin. The fatigue of the cell wall was simulated under normal refiner mechanical pulping conditions. A cyclic load was applied on the model fiber through a hemispherical grit proposed to be applied on the surface on refiner segments. Changes in the elastic modulus of the cell wall were analyzed to determine the potential for cell wall breakdown. An increase in the amplitude of applied forces and frequency of impacts was found to have a significant influence on the reduction of the elastic modulus of the wall structure. A high frequency of impacts increased the stiffness of the cell wall, but resulted in faster reduction of the elastic modulus. At a lower amplitude of impacts, efficient breakdown of the cell wall using grits was achieved with a high frequency of impacts or a high rotational speed of refiners.

  3. Building and degradation of secondary cell walls: are there common patterns of lamellar assembly of cellulose microfibrils and cell wall delamination?

    Science.gov (United States)

    De Micco, Veronica; Ruel, Katia; Joseleau, Jean-Paul; Aronne, Giovanna

    2010-08-01

    During cell wall formation and degradation, it is possible to detect cellulose microfibrils assembled into thicker and thinner lamellar structures, respectively, following inverse parallel patterns. The aim of this study was to analyse such patterns of microfibril aggregation and cell wall delamination. The thickness of microfibrils and lamellae was measured on digital images of both growing and degrading cell walls viewed by means of transmission electron microscopy. To objectively detect, measure and classify microfibrils and lamellae into thickness classes, a method based on the application of computerized image analysis combined with graphical and statistical methods was developed. The method allowed common classes of microfibrils and lamellae in cell walls to be identified from different origins. During both the formation and degradation of cell walls, a preferential formation of structures with specific thickness was evidenced. The results obtained with the developed method allowed objective analysis of patterns of microfibril aggregation and evidenced a trend of doubling/halving lamellar structures, during cell wall formation/degradation in materials from different origin and which have undergone different treatments. PMID:20532796

  4. Tensile test of plant cell wall analogs thin films using image stereocorrelation

    OpenAIRE

    Assor, Carole; Sabatier, Laurent; Cathala, Bernard; Aguié Béghin, Véronique; Arnould, Olivier

    2013-01-01

    The plant cell wall can be the optimal scale of investigation for understanding the properties and the variability of vegetal organs structure. At the molecular scale, the wall constituents’ organisation might have a strong influence on theses properties. Primary cell walls are separated into monocotyledons (cereals) and dicotyledons (fleshy fruits) depending on the type of molecules involved (cellulose, hemicelluloses, pectin, etc.). These polymers structures and concentration within the cel...

  5. Impact of Cell Wall Composition on Maize Resistance to Pests and Diseases

    OpenAIRE

    Malvar, Rosa A.; Rogelio Santiago; Jaime Barros-Rios

    2013-01-01

    In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form mixed lignins. Several of these cell wall components show a determinative role in maize resistance to pest and diseases. However, defense mechanisms are very complex and vary among t...

  6. Immuno and Affinity Cytochemical Analysis of Cell Wall Composition in the Moss Physcomitrella patens.

    Science.gov (United States)

    Berry, Elizabeth A; Tran, Mai L; Dimos, Christos S; Budziszek, Michael J; Scavuzzo-Duggan, Tess R; Roberts, Alison W

    2016-01-01

    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. PMID:27014284

  7. Morphologic and functional alterations induced by low doses of mercuric chloride in the kidney OK cell line: ultrastructural evidence for an apoptotic mechanism of damage

    International Nuclear Information System (INIS)

    Mercury produces acute renal failure in experimental animal models, but the mechanism of tubular injury has not completely been clarified. There is an increased interest in the role of apoptosis in the pathogenesis of renal diseases that result primarily from injury to renal tubular epithelial cells. However, detailed studies of morpho-functional alterations induced by mercuric chloride in kidney cell lines are scarce. This work characterizes these alterations in OK cell cultures. Morphological alterations were profiled using light microscopy, transmission electron microscopy, and confocal microscopy, as well as mitochondrial functional assays in the cells exposed to low concentrations of HgCl2. At concentrations of 1 and 10 μM of HgCl2 there were no morphological or ultrastructural alterations, but the mitochondrial function (MTT assay) and intracellular ATP content was increased, especially at longer incubation times (6 and 9 h). At 15 μM HgCl2, both the mitochondrial activity and the endogenous ATP decreased significantly. At this concentration the OK cells rounded up, had increased number of cytoplasmic vacuoles, and detached from the cell monolayer. At 15 μM HgCl2 ultrastructural changes were characterized by dispersion of the ribosomes, dilatation of the cisterns of the rough endoplasmic reticulum, increase of number of cytoplasmic vacuoles, chromatin condensation, invaginations of the nuclear envelope, presence of cytoplasmic inclusion bodies, and alterations in the size and morphology of mitochondria. At 15 μM HgCl2 apoptotic signs included membrane blebbing, chromatin condensation, mitochondrial alterations, apoptotic bodies, and nuclear envelope rupture. Using confocal microscopy and the mitochondrial specific dye MitoTracker Red, it was possible to establish qualitative changes induced by mercury on the mitochondrial membrane potential after incubation of the cells for 6 and 9 h with 15 μM HgCl2. This effect was not observed at short times (1 and 3

  8. DNB test results for R grid thimble cold wall cells

    International Nuclear Information System (INIS)

    Two sets of type ''R'' mixing vane grid DNB data from a 4 x 4 rod bundle, where one of the central rods is a simulated control rod thimble, are presented. The range of parameters for this thimble cold wall data is given. The results show that the W-3 correlation with cold wall factor and the Modified Spacer Factor is applicable to ''R'' grid thimble cold wall rod bundle data. (7 references) (auth)

  9. Genome-Wide Association Mapping for Cell Wall Composition and Properties in Temperate Grasses

    DEFF Research Database (Denmark)

    Bellucci, Andrea

    -glucans. Plant cell wall biosynthesis is regulated by a large number of genes and regulatory factors but very few of these are known and characterized. This PhD project aimed to the identification of putative candidate genes involved in plant cell wall composition and properties using a genome wide (GWAS...

  10. Consolidated pretreatment and hydrolysis of plant biomass expressing cell wall degrading enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Raab, R. Michael; Zhang, Dongcheng; Bougri, Oleg

    2016-02-02

    Methods for consolidated pretreatment and hydrolysis of genetically engineered plants expressing cell wall degrading enzymes are provided. Expression cassettes and vectors for making transgenic plants are described. Plants engineered to express one or more cell wall degrading enzymes using expression cassettes and vectors of the invention are also provided.

  11. CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

    Directory of Open Access Journals (Sweden)

    TABORDA Valeria B.A.

    1999-01-01

    Full Text Available Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.

  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

    2012-01-01

    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. Structure of the cell wall of mango after application of ionizing radiation

    International Nuclear Information System (INIS)

    Cells of the mesocarp of mango cultivar Tommy Atkins were analyzed by Transmission Electron Microscope—TEM to evaluate the effects of doses of 0.5 and 1.0 kGy applied immediately after the fruit and after storage for twenty days at a temperature of 12 °C followed by 5 days of simulated marketing at a temperature of 21 °C. No alteration was found in the structure of the cell wall, middle lamella, and plasma membrane of fruits when analyzed immediately after application of doses. The mesocarp cell structure of the cell wall, middle lamella, and the plasma membrane did however undergo changes after storage. Fruits that received a dose of 0.5 kGy displayed slight changes in cell wall structure and slight disintegration of the middle lamella. Fruits that received a dose of 1.0 kGy displayed more severe changes in the structure of the cell wall, greater middle lamella degradation, and displacement of the plasma membrane. - Highlights: ► Mesocarp cells were analyzed by Transmission Electron Microscope—TEM. ► No change in cell wall structure, middle lamella and plasma membrane was found in fruits immediately after irradiation. ► Changes in cell wall structure, middle lamella and plasma membrane happened after storage. ► Fruits subjected to 0.5 kGy showed smaller cell wall change.

  14. Clinostation influence on regeneration of cell wall in Solanum Tuberosum L. protoplasts

    Science.gov (United States)

    Nedukha, Elena M.; Sidorov, V. A.; Samoylov, V. M.

    1994-08-01

    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.

  15. Non-invasive imaging of cellulose microfibril orientation within plant cell walls by polarized Raman microspectroscopy.

    Science.gov (United States)

    Sun, Lan; Singh, Seema; Joo, Michael; Vega-Sanchez, Miguel; Ronald, Pamela; Simmons, Blake A; Adams, Paul; Auer, Manfred

    2016-01-01

    Cellulose microfibrils represent the major scaffold of plant cell walls. Different packing and orientation of the microfibrils at the microscopic scale determines the macroscopic properties of cell walls and thus affect their functions with a profound effect on plant survival. We developed a polarized Raman microspectroscopic method to determine cellulose microfibril orientation within rice plant cell walls. Employing an array of point measurements as well as area imaging and subsequent Matlab-assisted data processing, we were able to characterize the distribution of cellulose microfibril orientation in terms of director angle and anisotropy magnitude. Using this approach we detected differences between wild type rice plants and the rice brittle culm mutant, which shows a more disordered cellulose microfibril arrangement, and differences between different tissues of a wild type rice plant. This novel non-invasive Raman imaging approach allows for quantitative assessment of cellulose fiber orientation in cell walls of herbaceous plants, an important advancement in cell wall characterization. PMID:26137889

  16. The three-dimensional structure of the cell wall glycoprotein of Chlorogonium elongatum.

    Science.gov (United States)

    Shaw, P J; Hills, G J

    1984-06-01

    The green alga Chlorogonium elongatum, a member of the Volvocales, possesses a crystalline cell wall composed of hydroxyproline-rich glycoprotein similar to the primary cell wall glycoproteins of higher plants. Electron microscopy and computer image processing have been used to determine the crystal structure of the Chlorogonium cell wall in three dimensions to a resolution of 2.0 nm. The structure is composed of heterologous dimers. Each subunit of the dimer comprises a long, thin spacer domain and a large globular domain, which is the site of the intra- and inter-dimer interactions. There are also sites of intersubunit interactions at the opposite ends of the rod domains. We suggest that the rods are composed predominantly of glycosylated polyproline helix, as has been suggested for higher plant cell wall glycoproteins and has been shown for the cell wall glycoprotein of Chlamydomonas reinhardtii, which is closely related to Chlorogonium. PMID:6490737

  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;

    2014-01-01

    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...... probes. Moreover, homogalacturonan and callose were shown to be significant predictors for fiber length. The role of these polysaccharides was already pointed out in previous cell wall elongation studies. Additional relationships were predicted for fiber strength and elongation which will need further...

  18. A new picture of cell wall protein dynamics in elongating cells of Arabidopsis thaliana: Confirmed actors and newcomers

    OpenAIRE

    Jamet Elisabeth; Pont-Lezica Rafael; Borderies Gisèle; Canut Hervé; Irshad Muhammad

    2008-01-01

    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 g...

  19. Intracellular vesicles as reproduction elements in cell wall-deficient L-form bacteria

    OpenAIRE

    Briers, Yves; Staubli, Titu; Schmid, Markus C; Wagner, Michael; Schuppler, Markus; Loessner, Martin J.

    2012-01-01

    Cell wall-deficient bacteria, or L-forms, represent an extreme example of bacterial plasticity. Stable L-forms can multiply and propagate indefinitely in the absence of a cell wall. Data presented here are consistent with the model that intracellular vesicles in Listeria monocytogenes L-form cells represent the actual viable reproductive elements. First, small intracellular vesicles are formed along the mother cell cytoplasmic membrane, originating from local phospholipid accumulation. During...

  20. Decreased Polysaccharide Feruloylation Compromises Plant Cell Wall Integrity and Increases Susceptibility to Necrotrophic Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Nathan T Reem

    2016-05-01

    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.

  1. Single-Wall Carbon Nanotube Anodes for Lithium Cells

    Science.gov (United States)

    Hepp, Aloysius F.; Raffaelle, Ryne; Gennett, Tom; Kumta, Prashant; Maranchi, Jeff; Heben, Mike

    2006-01-01

    In recent experiments, highly purified batches of single-wall carbon nanotubes (SWCNTs) have shown promise as superior alternatives to the graphitic carbon-black anode materials heretofore used in rechargeable thin-film lithium power cells. The basic idea underlying the experiments is that relative to a given mass of graphitic carbon-black anode material, an equal mass of SWCNTs can be expected to have greater lithium-storage and charge/discharge capacities. The reason for this expectation is that whereas the microstructure and nanostructure of a graphitic carbon black is such as to make most of the interior of the material inaccessible for intercalation of lithium, a batch of SWCNTs can be made to have a much more open microstructure and nanostructure, such that most of the interior of the material is accessible for intercalation of lithium. Moreover, the greater accessibility of SWCNT structures can be expected to translate to greater mobilities for ion-exchange processes and, hence, an ability to sustain greater charge and discharge current densities.

  2. Effects of cadmium and copper on the ultrastructure ofAnkistrodesmus braunii andAnabaena 7120.

    Science.gov (United States)

    Massalski, A; Laube, V M; Kushner, D J

    1981-06-01

    The effects of brief exposure to, or growth in the presence of, lethal and sublethal concentrations of Cu(NO)2 and Cd(NO3) on the ultrastructure of the blue-green algaAnabaena 7120 and the green algaAnkistrodesmus braunii were studied. Exposure to increasing amount of both metal ions led to the appearance of larger proportions of electron-dense cells whose organelles were less well defined than those of untreated cells. Metal-treated cells ofAnabaena 7120 became distorted. Some had a corrugated appearance. Others lysed, leaving a much larger proportion of heterocysts. Such heterocysts were often empty or had a curious collapsed appearance. Growth ofA. braunii in the presence of 10(-4) M Cu(NO2)2 produced substantial numbers of multinucleate giant cells with thick walls; such cells result from repeated mitotic division without subsequent cytokinesis. The giant cells contained centrioles, structures not as yet found in normal cells of the genusAnkistrodesmus. Some nuclei of giant, but not of normal, cells contained deep indentations that appeared as "holes" in cross section. Some giant cells also contained triple parallel strands of endoplasmic reticulum which extended across much of the cell, connecting to the nuclear envelope. Some ultrastructural changes were also noted in algal cells grown over sediment containing Cu or Cd, but these were generally less severe than those occurring when metal ions were added directly to the algal cultures. PMID:24227427

  3. Spermatozoon ultrastructure of Thysanotaenia congolensis (Cyclophyllidea, Anoplocephalidae, Inermicapsiferinae): phylogenetic implications.

    Science.gov (United States)

    Miquel, Jordi; Świderski, Zdzisław; Feliu, Carlos

    2016-08-01

    The mature spermatozoon of Thysanotaenia congolensis, an intestinal parasite of black rat Rattus rattus from Cape Verde, is described by means of transmission electron microscopy. The ultrastructural organization of the sperm cell of T. congolensis follows Levron et al.'s type VII of the Eucestoda. It corresponds to a uniflagellate spermatozoon that presents crested bodies, periaxonemal sheath and intracytoplasmic walls, spiralled cortical microtubules and nucleus spiralled around the axoneme. These characteristics are also present in the spermatozoa of other inermicapsiferines and differ from the characters found in species belonging to the remaining subfamilies of anoplocephalids, namely Anoplocephalinae, Linstowiinae and Thysanosomatinae. Several authors consider the family Anoplocephalidae as a polyphyletic group, and its relationships with the Davaineidae are a matter of controversy. The phylogenetic implications of spermatological ultrastructural features present in inermicapsiferines and in the remaining anoplocephalids are discussed, and the available data on anoplocephalids are compared to similar results in davaineids in order to contribute to a better knowledge of relationships between these cyclophyllidean families. PMID:27083191

  4. Identification of the cell wall receptor for Candida nodaensis Killer toxin

    OpenAIRE

    Silva, Sónia Carina; Aguiar, Cristina; Veríssimo, P.; Pires, E.; Lucas, Cândida

    2004-01-01

    Comunicação efectuada no XIV Congresso Nacional de Bioquímica em Vilamoura (Portugal), 2004. The biological action of the K toxins involves a first step in the killing process, which correspond to the adsorption the toxin to the cell wall of sensitive cells. Here we describe the work performed towards the identification of the cell wall receptor for the zymocin under this study. For this purpose, the main cell wall components of the sensitive yeast Pichia guilliermondii were extracted. Th...

  5. Atomic Force Microscopy Measurements of the Mechanical Properties of Cell Walls on Living Bacterial Cells

    Science.gov (United States)

    Bailey, Richard; Mullin, Nic; Turner, Robert; Foster, Simon; Hobbs, Jamie

    2014-03-01

    Staphylococcus aureus is a major cause of infection in humans, including the Methicillin resistant strain, MRSA. However, very little is known about the mechanical properties of these cells. Our investigations use AFM to examine live S. aureus cells to quantify mechanical properties. These were explored using force spectroscopy with different trigger forces, allowing the properties to be extracted at different indentation depths. A value for the cell wall stiffness has been extracted, along with a second, higher value which is found upon indenting at higher forces. This higher value drops as the cells are exposed to high salt, sugar and detergent concentrations, implying that this measurement contains a contribution from the internal turgor pressure. We have monitored these properties as the cells progress through the cell cycle. Force maps were taken over the cells at different stages of the growth process to identify changes in the mechanics throughout the progression of growth and division. The effect of Oxacillin has also been studied, to better understand its mechanism of action. Finally mutant strains of S. aureus and a second species Bacillus subtilis have been used to link the mechanical properties of the cell walls with the chain lengths and substructures involved.

  6. Genetic modification of plant cell walls to enhance biomass yield and biofuel production in bioenergy crops.

    Science.gov (United States)

    Wang, Yanting; Fan, Chunfen; Hu, Huizhen; Li, Ying; Sun, Dan; Wang, Youmei; Peng, Liangcai

    2016-01-01

    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. PMID:27269671

  7. 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

    2008-09-01

    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.

  8. Trifluoromethanesulfonic acid-based proteomic analysis of cell wall and secreted proteins of the ascomycetous fungi Neurospora crassa and Candida albicans.

    Science.gov (United States)

    Maddi, Abhiram; Bowman, Shaun M; Free, Stephen J

    2009-10-01

    Cell wall proteins from purified Candida albicans and Neurospora crassa cell walls were released using trifluoromethanesulfonic acid (TFMS) which cleaves the cell wall glucan/chitin matrix and deglycosylates the proteins. The cell wall proteins were then characterized by SDS-PAGE and identified by proteomic analysis. The analyses for C. albicans identified 15 cell wall proteins and six secreted proteins. For N. crassa, the analyses identified 26 cell wall proteins and nine secreted proteins. Most of the C. albicans cell wall proteins are found in the cell walls of both yeast and hyphae cells, but some cell type-specific cell wall proteins were observed. The analyses showed that the pattern of cell wall proteins present in N. crassa vegetative hyphae and conidia (asexual spores) are quite different. Almost all of the cell wall proteins identified in N. crassa have close homologs in the sequenced fungal genomes, suggesting that these proteins have important conserved functions within the cell wall. PMID:19555771

  9. Cell Wall Nonlinear Elasticity and Growth Dynamics: How Do Bacterial Cells Regulate Pressure and Growth?

    Science.gov (United States)

    Deng, Yi

    In my thesis, I study intact and bulging Escherichia coli cells using atomic force microscopy to separate the contributions of the cell wall and turgor pressure to the overall cell stiffness. I find strong evidence of power--law stress--stiffening in the E. coli cell wall, with an exponent of 1.22±0.12, such that the wall is significantly stiffer in intact cells (E = 23±8 MPa and 49±20 MPa in the axial and circumferential directions) than in unpressurized sacculi. These measurements also indicate that the turgor pressure in living cells E. coli is 29±3 kPa. The nonlinearity in cell elasticity serves as a plausible mechanism to balance the mechanical protection and tension measurement sensitivity of the cell envelope. I also study the growth dynamics of the Bacillus subtilis cell wall to help understand the mechanism of the spatiotemporal order of inserting new cell wall material. High density fluorescent markers are used to label the entire cell surface to capture the morphological changes of the cell surface at sub-cellular to diffraction-limited spatial resolution and sub-minute temporal resolution. This approach reveals that rod-shaped chaining B. subtilis cells grow and twist in a highly heterogeneous fashion both spatially and temporally. Regions of high growth and twisting activity have a typical length scale of 5 μm, and last for 10-40 minutes. Motivated by the quantification of the cell wall growth dynamics, two microscopy and image analysis techniques are developed and applied to broader applications beyond resolving bacterial growth. To resolve densely distributed quantum dots, we present a fast and efficient image analysis algorithm, namely Spatial Covariance Reconstruction (SCORE) microscopy that takes into account the blinking statistics of the fluorescence emitters. We achieve sub-diffraction lateral resolution of 100 nm from 5 to 7 seconds of imaging, which is at least an order of magnitude faster than single-particle localization based methods

  10. Navigating the transcriptional roadmap regulating plant secondary cell wall deposition

    Directory of Open Access Journals (Sweden)

    Steven Grant Hussey

    2013-08-01

    Full Text Available The current status of lignocellulosic biomass as an invaluable resource in industry, agriculture and health has spurred increased interest in understanding the transcriptional regulation of secondary cell wall (SCW biosynthesis. The last decade of research has revealed an extensive network of NAC, MYB and other families of transcription factors regulating Arabidopsis SCW biosynthesis, and numerous studies have explored SCW-related transcription factors in other dicots and monocots. Whilst the general structure of the Arabidopsis network has been a topic of several reviews, they have not comprehensively represented the detailed protein-DNA and protein-protein interactions described in the literature, and an understanding of network dynamics and functionality has not yet been achieved for SCW formation. Furthermore the methodologies employed in studies of SCW transcriptional regulation have not received much attention, especially in the case of non-model organisms. In this review, we have reconstructed the most exhaustive literature-based network representations to date of SCW transcriptional regulation in Arabidopsis. We include a manipulable Cytoscape representation of the Arabidopsis SCW transcriptional network to aid in future studies, along with a list of supporting literature for each documented interaction. Amongst other topics, we discuss the various components of the network, its evolutionary conservation in plants, putative modules and dynamic mechanisms that may influence network function, and the approaches that have been employed in network inference. Future research should aim to better understand network function and its response to dynamic perturbations, whilst the development and application of genome-wide approaches such as ChIP-seq and systems genetics are in progress for the study of SCW transcriptional regulation in non-model organisms.

  11. Xyloglucans from flaxseed kernel cell wall: Structural and conformational characterisation.

    Science.gov (United States)

    Ding, Huihuang H; Cui, Steve W; Goff, H Douglas; Chen, Jie; Guo, Qingbin; Wang, Qi

    2016-10-20

    The structure of ethanol precipitated fraction from 1M KOH extracted flaxseed kernel polysaccharides (KPI-EPF) was studied for better understanding the molecular structures of flaxseed kernel cell wall polysaccharides. Based on methylation/GC-MS, NMR spectroscopy, and MALDI-TOF-MS analysis, the dominate sugar residues of KPI-EPF fraction comprised of (1,4,6)-linked-β-d-glucopyranose (24.1mol%), terminal α-d-xylopyranose (16.2mol%), (1,2)-α-d-linked-xylopyranose (10.7mol%), (1,4)-β-d-linked-glucopyranose (10.7mol%), and terminal β-d-galactopyranose (8.5mol%). KPI-EPF was proposed as xyloglucans: The substitution rate of the backbone is 69.3%; R1 could be T-α-d-Xylp-(1→, or none; R2 could be T-α-d-Xylp-(1→, T-β-d-Galp-(1→2)-α-d-Xylp-(1→, or T-α-l-Araf-(1→2)-α-d-Xylp-(1→; R3 could be T-α-d-Xylp-(1→, T-β-d-Galp-(1→2)-α-d-Xylp-(1→, T-α-l-Fucp-(1→2)-β-d-Galp-(1→2)-α-d-Xylp-(1→, or none. The Mw of KPI-EPF was calculated to be 1506kDa by static light scattering (SLS). The structure-sensitive parameter (ρ) of KPI-EPF was calculated as 1.44, which confirmed the highly branched structure of extracted xyloglucans. This new findings on flaxseed kernel xyloglucans will be helpful for understanding its fermentation properties and potential applications. PMID:27474598

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

    Science.gov (United States)

    Coll-Almela, Luis; Saura-López, Domingo; Laencina-Sánchez, José; Schols, Henk A; Voragen, Alfons G J; Ros-García, José María

    2015-05-15

    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 pectin fraction (DASS), a 1M sodium hydroxide-soluble hemicellulose fraction (1MASS), a 4M sodium hydroxide-soluble hemicellulose fraction (4MASS) and a cellulose-rich residue (3.1, 0.9, 0.4, 0.7 and 1.6%w/w of fresh membrane, respectively). The ChSS pectin consisted mainly of galacturonic acid followed by arabinose and galactose. The DASS fraction contained less galacturonic acid and more neutral sugars than ChSS. Eighty-nine percent of the galacturonic acid present in the segment membranes was recovered in the above two pectin fractions. The two hemicellulosic fractions consisted of two different molecular weight populations, which also differed in their sugar composition. Arabinose, xylose, mannose, galactose and glucose were the main sugar constituents of these hemicellulose fractions. In addition to an (arabino)xylan and a xyloglucan, the presence of an arabinogalactan is suggested by the sugar composition of both hemicelluloses. The pectin fractions were also characterised by their degradability by the pectic enzymes polygalacturonase, pectinmethylesterase and rhamnogalacturonan hydrolase. However the degree of degradation of the pectin fractions by enzymes differed, and the amount of the polymeric materials resistant to further degradation and the oligomeric products also differed. Using pectic enzymes it is possible to obtain peeled mandarin segments ready to eat or for canning. PMID:25577048

  13. Investigating the role of pectin in carrot cell wall changes during thermal processing: A microscopic approach

    OpenAIRE

    Ribas, Albert; Van Buggenhout, Sandy; Palmero, Paola; Hendrickx, Marc; Van Loey, Ann

    2014-01-01

    Changes in cell wall integrity upon thermal treatment were assessed in carrot cells using novel microscopic approaches using Congo red and different cell wall polysaccharide specific probes (JIM7, LM10, LM11, LM15, LM21, LM22 and CBM3a). Strong thermal processing induced an increased accessibility of cellulose and hemicelluloses by Congo red and the specific probes, except galactomannan, which detection was not affected by the thermal processing. Detection of pectin by JIM7 disappeared upon t...

  14. Evaluation of Chlorella (Chlorophyta) as Source of Fermentable Sugars via Cell Wall Enzymatic Hydrolysis

    OpenAIRE

    Marcoaurélio Almenara Rodrigues; Elba Pinto da Silva Bon

    2011-01-01

    The cell wall of Chlorella is composed of up to 80% carbohydrates including cellulose. In this study, Chlorella homosphaera and Chlorella zofingiensis were evaluated as source of fermentable sugars via their cell wall enzymatic degradation. The algae were cultivated in inorganic medium, collected at the stationary growth phase and centrifuged. The cell pellet was suspended in citrate buffer, pH 4.8 and subjected to 24 hours hydrolysis at 50°C using a cellulases, xylanases, and amylases ble...

  15. 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

    2010-01-01

    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...

  16. Investigating the effect of carbon nanotube diameter and wall number in carbon nanotube/silicon heterojunction solar cells

    OpenAIRE

    Tom Grace; LePing Yu; Christopher Gibson; Daniel Tune; Huda Alturaif; Zeid Al Othman; Joseph Shapter

    2016-01-01

    Suspensions of single-walled, double-walled and multi-walled carbon nanotubes (CNTs) were generated in the same solvent at similar concentrations. Films were fabricated from these suspensions and used in carbon nanotube/silicon heterojunction solar cells and their properties were compared with reference to the number of walls in the nanotube samples. It was found that single-walled nanotubes generally produced more favorable results; however, the double and multi-walled nanotube films used in...

  17. 'Strengthening the fungal cell wall through chitin-glucan cross-links: effects on morphogenesis and cell integrity'.

    Science.gov (United States)

    Arroyo, Javier; Farkaš, Vladimír; Sanz, Ana Belén; Cabib, Enrico

    2016-09-01

    The cross-linking of polysaccharides to assemble new cell wall in fungi requires transglycosylation mechanisms by which preexisting glycosidic linkages are broken and new linkages are created between the polysaccharides. The molecular mechanisms for these processes, which are essential for fungal cell biology, are only now beginning to be elucidated. Recent development of in vivo and in vitro biochemical approaches has allowed characterization of important aspects about the formation of chitin-glucan covalent cell wall cross-links by cell wall transglycosylases of the CRH family and their biological function. Covalent linkages between chitin and glucan mediated by Crh proteins control morphogenesis and also play important roles in the remodeling of the fungal cell wall as part of the compensatory responses necessary to counterbalance cell wall stress. These enzymes are encoded by multigene families of redundant proteins very well conserved in fungal genomes but absent in mammalian cells. Understanding the molecular basis of fungal adaptation to cell wall stress through these and other cell wall remodeling enzymatic activities offers an opportunity to explore novel antifungal treatments and to identify potential fungal virulence factors. PMID:27185288

  18. Identification of a Streptococcus salivarius Cell Wall Component Mediating Coaggregation with Veillonella alcalescens VI

    Science.gov (United States)

    Weerkamp, Anton H.; McBride, Barry C.

    1981-01-01

    Cell walls of Streptococcus salivarius HB aggregated Veillonella alcalescens V1, but cell walls of the mutant S. salivarius HB-V5 did not. We found no correlation between the presence of fimbriae on streptococcal walls and the ability to aggregate Veillonella strains. Treatment of the walls with lysozyme solubilized a fraction which possessed Veillonella-aggregating activity. Solubilized cell wall preparations of strain HB contained three major (glyco)proteins as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and at least four antigens as determined by immunoelectrophoresis with antiserum prepared against strain HB walls. A specific antiserum, which was obtained by adsorption of anti-HB serum on strain HB-V5 cells, contained monospecific antibody that reacted with the solubilized strain HB wall preparation. Similar fractions prepared from strain HB-V5 cell walls did not possess aggregating activity and lacked one protein band (protein I) after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and one antigen (antigen b) after immunoelectrophoresis. The same antigen was absent when lysozyme-solubilized wall preparations of strain HB were reacted with anti-HB-V5 serum. Crossed-immunoisoelectric focusing indicated that this specific (glyco)protein and this antigen were identical and had an isoelectric point of 4.60. Protein I and antigen b were specifically adsorbed when solubilized strain HB cell walls were incubated with V. alcalescens V1 but were not adsorbed by nonaggregating Veillonella parvula ATCC 10790 cells. Culture supernatants of strain HB contained V. alcalescens V1-aggregating activity. Antigen b was present in the culture supernatant, but was not found in cultures of strain HB-V5. A total of 18 S. salivarius isolates possessing the streptococcal group K antigen released aggregating activity and antigen b into the culture medium, but 11 strains which lacked the K-antigen did not. Images PMID:7251145

  19. Proteomics of loosely bound cell wall proteins of Arabidopsis thaliana cell suspension cultures: a critical analysis.

    OpenAIRE

    Borderies, Gisèle; Jamet, Elisabeth; Lafitte, Claude; Rossignol, Michel; Jauneau, Alain; Boudart, Georges; Monsarrat, Bernard; Esquerré-Tugayé, Marie-Thérèse; Boudet, Alain; Pont-Lezica, Rafael

    2003-01-01

    The complete sequencing of the Arabidopsis thaliana genome allows the use of the recently developed mass spectrometry techniques to identify the cell wall proteins (CWPs). Most proteomic approaches depend on the quality of sample preparation. Extraction of CWPs is particularly complex since the proteins may be free in the apoplast or are embedded in a polysaccharide matrix where they are retained by Van der Waals interactions, hydrogen bonds, hydrophobic or ionic interactions, or cross-linked...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue. In essence, plant cell expansion represents the foundation of development. Most studies of plant cell expansion...

  1. Recent advances on the posttranslational modifications of EXTs and their roles in plant cell walls

    DEFF Research Database (Denmark)

    Velasquez, Melina; Salter, Juan Salgado; Dorosz, Javier Gloazzo;

    2012-01-01

    The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O......-glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4...... and function of extensins in plant cell walls....

  2. Temperature Gradients on the Cell Wall in the Critical Viscosity Experiment

    Science.gov (United States)

    Berg, Robert F.; Moldover, Michael R.

    1993-01-01

    Because of the diverging susceptibility delta rho/delta Tau near the liquid-vapor critical point, temperature gradients must be kept small to maintain adequate sample homogeneity. In our Science Requirements Document we paid particular attention to radial density gradients caused by equilibration of the xenon sample. Axial density gradients were addressed through the requirement that the cell's copper wall have a gradient less than 22 microK/m. This report re-examines the cell wall's temperature distribution in more detail by estimating all known significant contributions to temperature differences on the cell's wall.

  3. Evidence for land plant cell wall biosynthetic mechanisms in charophyte green algae

    DEFF Research Database (Denmark)

    Mikkelsen, Maria Dalgaard; Harholt, Jesper; Ulvskov, Peter;

    2014-01-01

    BACKGROUND AND AIMS: The charophyte green algae (CGA) are thought to be the closest living relatives to the land plants, and ancestral CGA were unique in giving rise to the land plant lineage. The cell wall has been suggested to be a defining structure that enabled the green algal ancestor to...... colonize land. These cell walls provide support and protection, are a source of signalling molecules, and provide developmental cues for cell differentiation and elongation. The cell wall of land plants is a highly complex fibre composite, characterized by cellulose cross-linked by non......-cellulosic polysaccharides, such as xyloglucan, embedded in a matrix of pectic polysaccharides. How the land plant cell wall evolved is currently unknown: early-divergent chlorophyte and prasinophyte algae genomes contain a low number of glycosyl transferases (GTs), while land plants contain hundreds. The number of GTs in...

  4. Role of (1,3)(1,4)-β-glucan in cell walls: interaction with cellulose.

    Science.gov (United States)

    Kiemle, Sarah N; Zhang, Xiao; Esker, Alan R; Toriz, Guillermo; Gatenholm, Paul; Cosgrove, Daniel J

    2014-05-12

    (1,3)(1,4)-β-D-Glucan (mixed-linkage glucan or MLG), a characteristic hemicellulose in primary cell walls of grasses, was investigated to determine both its role in cell walls and its interaction with cellulose and other cell wall polysaccharides in vitro. Binding isotherms showed that MLG adsorption onto microcrystalline cellulose is slow, irreversible, and temperature-dependent. Measurements using quartz crystal microbalance with dissipation monitoring showed that MLG adsorbed irreversibly onto amorphous regenerated cellulose, forming a thick hydrogel. Oligosaccharide profiling using endo-(1,3)(1,4)-β-glucanase indicated that there was no difference in the frequency and distribution of (1,3) and (1,4) links in bound and unbound MLG. The binding of MLG to cellulose was reduced if the cellulose samples were first treated with certain cell wall polysaccharides, such as xyloglucan and glucuronoarabinoxylan. The tethering function of MLG in cell walls was tested by applying endo-(1,3)(1,4)-β-glucanase to wall samples in a constant force extensometer. Cell wall extension was not induced, which indicates that enzyme-accessible MLG does not tether cellulose fibrils into a load-bearing network. PMID:24678830

  5. The role of the secondary cell wall in plant resistance to pathogens.

    Science.gov (United States)

    Miedes, Eva; Vanholme, Ruben; Boerjan, Wout; Molina, Antonio

    2014-01-01

    Plant resistance to pathogens relies on a complex network of constitutive and inducible defensive barriers. The plant cell wall is one of the barriers that pathogens need to overcome to successfully colonize plant tissues. The traditional view of the plant cell wall as a passive barrier has evolved to a concept that considers the wall as a dynamic structure that regulates both constitutive and inducible defense mechanisms, and as a source of signaling molecules that trigger immune responses. The secondary cell walls of plants also represent a carbon-neutral feedstock (lignocellulosic biomass) for the production of biofuels and biomaterials. Therefore, engineering plants with improved secondary cell wall characteristics is an interesting strategy to ease the processing of lignocellulosic biomass in the biorefinery. However, modification of the integrity of the cell wall by impairment of proteins required for its biosynthesis or remodeling may impact the plants resistance to pathogens. This review summarizes our understanding of the role of the plant cell wall in pathogen resistance with a focus on the contribution of lignin to this biological process. PMID:25161657

  6. 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

    2011-01-01

    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.

  7. Changes in cell wall architecture of wheat coleoptiles grown under continuous hypergravity conditions

    Science.gov (United States)

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

    Modifications of cell wall structure of wheat coleoptiles in response to continuous hypergravity (300 g) treatment were investigated. Length of coleoptiles exposed to hypergravity for 2-4 days from germination stage was 60-70% of that of 1 g control. The net amounts of cell wall polysaccharides, such as hemicellulose and cellulose, of hypergravity-treated coleoptiles increased as much as those of 1 g control coleoptiles during the incubation period. As a result, the levels of cell wall polysaccharides per unit length of coleoptile, which mean the thickness of cell walls, largely increased under hypergravity conditions. Particularly, the amounts of hemicellulosic polymers with middle molecular mass (0.2-1 MDa) largely increased from day 2 to 3 under hypergravity conditions. The major sugar components of the hemicellulose fraction are arabinose, xylose and glucose. The ratios of arabinose and xylose to glucose were higher in hypergravity-treated coleoptiles than in control coleoptiles. The fractionation of hemicellulosic polymers into the neutral and acidic polymers by the anion-exchange column showed that the levels of acidic polymers (mainly composed of arabinoxylans) in cell walls of hypergravity-treated coleoptiles were higher than those of control coleoptiles. In addition to wall polysaccharides, the amounts of cell wall-bound phenolics, such as ferulic acid and diferulic acid, substantially increased during the incubation period both in 1 g control and hypergravity-treated coleoptiles. Especially, the levels of diferulic acid which cross-links hemicellulosic polymers were higher in hypergravity-treated coleoptiles than in control coleoptiles during the incubation period. These results suggest that hypergravity stimuli from the germination stage bias the type of synthesized hemicellulosic polysaccharides, although they do not restrict the net synthesis of cell wall constituents in wheat coleoptiles. The stimulation of the synthesis of arabinoxylans and of the

  8. Specific labeling of peptidoglycan precursors as a tool for bacterial cell wall studies

    NARCIS (Netherlands)

    van Dam, V.; Olrichs, N.K.; Breukink, E.J.

    2009-01-01

    Wall chart: The predominant component of the bacterial cell wall, peptidoglycan, consists of long alternating stretches of aminosugar subunits interlinked in a large three-dimensional network and is formed from precursors through several cytosolic and membrane-bound steps. The high tolerance of the

  9. Improved methods for binding acma-type protein anchor fusions yo cell-wall material of micro-organisms

    NARCIS (Netherlands)

    Leenhouts, Cornelis; Ramasamy, R.; Steen, Anton; Kok, Jan; Buist, Girbe; Kuipers, Oscar

    2002-01-01

    The invention provides a method for improving binding of a proteinaceous substance to cell-wall material of a Gram-positive bacterium, said substance comprising an AcmA cell wall binding domain or homolog or functional derivative thereof, said method comprising treating said cell-wall material with

  10. Expression of S-adenosylmethionine Hydrolase in Tissues Synthesizing Secondary Cell Walls Alters Specific Methylated Cell Wall Fractions and Improves Biomass Digestibility

    Science.gov (United States)

    Eudes, Aymerick; Zhao, Nanxia; Sathitsuksanoh, Noppadon; Baidoo, Edward E. K.; Lao, Jeemeng; Wang, George; Yogiswara, Sasha; Lee, Taek Soon; Singh, Seema; Mortimer, Jenny C.; Keasling, Jay D.; Simmons, Blake A.; Loqué, Dominique

    2016-01-01

    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 AdoMet hydrolase (AdoMetase, E.C. 3.3.1.2) in secondary cell wall synthesizing tissues reduces the AdoMet pool and impacts lignin content and composition. In particular, both NMR analysis and pyrolysis gas chromatography mass spectrometry of lignin in engineered biomass showed relative enrichment of non-methylated p-hydroxycinnamyl (H) units and a reduction of dimethylated syringyl (S) units. This indicates a lower degree of methylation compared to that in wild-type lignin. Quantification of cell wall-bound hydroxycinnamates revealed a reduction of ferulate in AdoMetase transgenic lines. Biomass from transgenic lines, in contrast to that in control plants, exhibits an enrichment of glucose content and a reduction in the degree of hemicellulose glucuronoxylan methylation. We also show that these modifications resulted in a reduction of cell wall recalcitrance, because sugar yield generated by enzymatic biomass saccharification was greater than that of wild-type plants. Considering that transgenic plants show no important diminution of biomass yields, and that heterologous expression of AdoMetase protein can be spatiotemporally optimized, this novel approach provides a valuable option for the improvement of lignocellulosic biomass feedstock. PMID:27486577

  11. Expression of S-adenosylmethionine Hydrolase in Tissues Synthesizing Secondary Cell Walls Alters Specific Methylated Cell Wall Fractions and Improves Biomass Digestibility.

    Science.gov (United States)

    Eudes, Aymerick; Zhao, Nanxia; Sathitsuksanoh, Noppadon; Baidoo, Edward E K; Lao, Jeemeng; Wang, George; Yogiswara, Sasha; Lee, Taek Soon; Singh, Seema; Mortimer, Jenny C; Keasling, Jay D; Simmons, Blake A; Loqué, Dominique

    2016-01-01

    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 AdoMet hydrolase (AdoMetase, E.C. 3.3.1.2) in secondary cell wall synthesizing tissues reduces the AdoMet pool and impacts lignin content and composition. In particular, both NMR analysis and pyrolysis gas chromatography mass spectrometry of lignin in engineered biomass showed relative enrichment of non-methylated p-hydroxycinnamyl (H) units and a reduction of dimethylated syringyl (S) units. This indicates a lower degree of methylation compared to that in wild-type lignin. Quantification of cell wall-bound hydroxycinnamates revealed a reduction of ferulate in AdoMetase transgenic lines. Biomass from transgenic lines, in contrast to that in control plants, exhibits an enrichment of glucose content and a reduction in the degree of hemicellulose glucuronoxylan methylation. We also show that these modifications resulted in a reduction of cell wall recalcitrance, because sugar yield generated by enzymatic biomass saccharification was greater than that of wild-type plants. Considering that transgenic plants show no important diminution of biomass yields, and that heterologous expression of AdoMetase protein can be spatiotemporally optimized, this novel approach provides a valuable option for the improvement of lignocellulosic biomass feedstock. PMID:27486577

  12. Effects of external phosphorus on the cell ultrastructure and the chlorophyll content of maize under cadmium and zinc stress

    International Nuclear Information System (INIS)

    Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis, it was found that the ultrastructure of chloroplasts were changed, the shape of the chloroplasts altered and the numbers of grana that were asymmetrical increased; the numbers of grana and thylakoids decreased under the stress of Cd and Zn. The results indicated that the complex pollution involving Cd and Zn resulted in the membrane system of chloroplasts being damaged. When external phosphorus was applied, the numbers of damaged chloroplasts were significantly reduced and the nucleoli were better formed than those that did not receive phosphorus treatment. Moreover, many phosphate deposits were found in the vacuoles and on the surface of the roots, which were formed by phosphorus complexing with Cd (K sp = 2.53 x 10-33) and Zn (K sp = 9.00 x 10-33), respectively. Treatment with phosphorus conduced an increased chlorophyll content in plants compared with those that did not receive external phosphorus. - External P could decrease the bioavailability of Cd and Zn

  13. Investigation on Adsorption of Lithospermum erythrorhizon onto Fungal Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    孟琴; 薛莲

    2003-01-01

    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.

  14. Cell Wall Growth and Modulation Dynamics in a Model Unicellular Green Alga—Penium margaritaceum: Live Cell Labeling with Monoclonal Antibodies

    OpenAIRE

    Domozych, David S; Hannah Brechka; Alicia Britton; Marc Toso

    2011-01-01

    Penium margaritaceum is a unicellular charophycean green alga that possesses cell wall polymers similar to those of land plants. Several wall macromolecules of this alga are recognized by monoclonal antibodies specific for wall polymer epitopes of land plants. Immunofluorescence protocols using these antibodies may be employed to label specific cell wall constituents of live cells. Fluorescent labeling persists for several days, and this attribute allows for tracing of wall epitopes in both l...

  15. Identification and characterization of the BCG cell wall-stimulated suppressor cells in inbred rats

    International Nuclear Information System (INIS)

    In vitro experiments were undertaken to investigate the effect of intraperitoneal (i.p.) inoculation of BCG cell walls attached to oil droplets (BCGcw) on mitogenic and alloantigenic responses of spleen and bone marrow cells. These in vitro studies demonstrated that: (1) spleen cells from BCGcw-immunized ACI rats had decreased responsiveness to Concanavalin A (Con A) and to alloantigenic stimulation, (2) depressed Con A reactivity could also be induced in Buffalo rat spleen cells by the i.p. inoculation of BCGcw, (3) normal ACI rats had suppressor cells in their bone marrow but not in their spleens, (4) BCGcw-immunized ACI rats demonstrated an increase in the suppressive activity of their bone marrow as early as 1 day after inoculation of BCGcw, while suppressor activity was found in the spleen as early as 2 days after BCGcw inoculation, (5) characterization of the BCGcw-induced splenic suppressor cell demonstrated it to be adherent to plastic or nylon wool, radiation-resistant, and removed by treatment with carbonyl iron. These properties were consistent with the identification of the suppressor cell as a macrophage, (6) the Con A and mixed lymphocyte reactivities of normal spleen cells could be suppressed by the addition of the adherent spleen cell population from BCGcw-immunized ACI rats, and (7) the adherent suppressor cell from BCGcw-immunized rats suppressed Con A reactivity across a major histocompatability barrier. (Auth.)

  16. Trifluoromethanesulfonic acid-based proteomic analysis of cell wall and secreted proteins of the ascomycetous fungi Neurospora crassa and Candida albicans

    OpenAIRE

    Maddi, Abhiram; Bowman, Shaun M.; Free, Stephen J.

    2009-01-01

    Cell wall proteins from purified Candida albicans and Neurospora crassa cell walls were released using trifluoromethanesulfonic acid (TFMS) which cleaves the cell wall glucan/chitin matrix and deglycosylates the proteins. The cell wall proteins were then characterized by SDS PAGE and identified by proteomic analysis. The analyses for C. albicans identified 15 cell wall proteins and 6 secreted proteins. For N. crassa, the analyses identified 26 cell wall proteins and 9 secreted proteins. Most ...

  17. Turnover of galactans and other cell wall polysaccharides during development of flax plants

    International Nuclear Information System (INIS)

    We investigated the synthesis and turnover of cell wall polysaccharides of the flax (Linum usitatissimum L.) plant during development of the phloem fibers. One-month-old flax plants were exposed to a 40-min pulse with 14CO2 followed by 8-h, 24-h, and 1-month periods of chase with ambient CO2, and radioactivity in cell wall sugars was determined in various plant parts. The relative radioactivity of glucose in noncellulosic polysaccharides was the highest compared with all other cell wall sugars immediately after the pulse and decreased substantially during the subsequent chase. The relative radioactivities of the other cell wall sugars changed with differing rates, indicating turnover of specific polysaccharides. Notably, after 1 month of chase there was a marked decrease in the proportional mass and total radioactivity in cell wall galactose, indicating a long-term turnover of the galactans enriched in the fiber-containing tissues. The ratio of radiolabeled xylose to arabinose also increased during the chase, indicating a turnover of arabinose-containing polymers and interconversion to xylose. The pattern of label redistribution differed between organs, indicating that the cell wall turnover processes are tissue- and cell-specific

  18. Ultrastructural inquiries of the effects of X-radiation on melanocytes in monolayer cultures

    International Nuclear Information System (INIS)

    Melanocytes (HPM-73 cells) in monolayer culture, which in the exponential growth phase were irradiated with an X-ray dose of 8 Gy (800 rad) and 16 Gy (1600 rad), showed ultrastructural changes in the cell wall (for example, microvilli), in elements of the cytoskeleton (microtubules and microfilaments), of the mitochondria and a change in structures containing melanin (melanosomes/pre-melanosomes). As a control, melanocytes incubated in a culture medium containing serum were used. The irradiated cells showed morphologically tangible cell changes. It resulted in a strong development of the cytoskeleton (microtubules and microfilaments), an increase in lysosome-like structures, a re-orientation of cell wall structures in the form of a reduction of wall extensions (decrease in size of microvilli) and an increase in structures containing melanin. It was also noticed that the cells which had received 16 Gy (1600 rad) were damaged more than the cells which had received 8 Gy (800 rad), whereby the more highly irradiated cells still were not understood to be in 'disintegration'. All of these changes should be considered under the aspect of repair mechanisms after cell damage (irradiation). Altogether melanocytes are in comparison to other tumor cells less radiation sensitive. (orig.)

  19. Use of energy-filtering transmission electron microscopy for routine ultrastructural analysis of high-pressure-frozen or chemically fixed plant cells.

    Science.gov (United States)

    Lütz-Meindl, U; Aichinger, N

    2004-06-01

    In the present study energy-filtering transmission electron microscopy by use of an in-column spectrometer is employed as a powerful tool for ultrastructural analysis of plant cells. Images of unstained very thin (50 nm) and thick (140 nm) sections of the unicellular green alga Micrasterias denticulata, as a model system for a growing plant cell, taken by conventional transmission electron microscopy are compared to those obtained from filtering at zero energy loss (elastic bright field) and to those generated by energy filtering below the carbon-specific absorption edge at about 250 eV. The results show that the high-contrast images produced by the latter technique are distinctly superior in contrast and information content to micrographs taken at conventional transmission electron microscopy mode or at elastic bright field. Post- or en bloc staining with heavy metals, which is indispensable for conventional bright-field transmission electron microscopy, can be completely omitted. Delicate structural details such as membranous or filamentous connections between organelles, organelle interactions, or vesicle and vacuole contents are clearly outlined against the cytoplasmic background. Also, immunoelectron microscopic localization of macromolecules benefits from energy-filtering transmission electron microscopy by a better and more accurate assignment of antigens and structures and by facilitating the detection of immunomarkers without renunciation of contrast. PMID:15221520

  20. Early events of secretory granule formation in the rat parotid acinar cell under the influence of isoproterenol. An ultrastructural and lectin cytochemical study

    Directory of Open Access Journals (Sweden)

    F D’Amico

    2009-12-01

    Full Text Available The events involved in the maturation process of acinar secretory granules of rat parotid gland were investigated ultrastructurally and cytochemically by using a battery of four lectins [Triticum vulgaris agglutinin (WGA, Ulex europaeus agglutinin I (UEA-I, Glycine max agglutinin (SBA, Arachys hypogaea agglutinin (PNA]. In order to facilitate the study, parotid glands were chronically stimulated with isoproterenol to induce secretion. Specimens were embedded in the Lowicryl K4M resin. The trans-Golgi network (TGN derived secretory granules, which we refer to as immature secretory granules, were found to be intermediate structures in the biogenesis process of the secretory granules in the rat parotid acinar cell. These early structures do not seem to be the immediate precursor of the mature secretory granules: in fact, a subsequent interaction process between these early immature granule forms and TGN elements seems to occur, leading, finally, to the mature granules. These findings could explain the origin of the polymorphic subpopulations of the secretory granules in the normal acinar cells of the rat parotid gland. The lectin staining patterns were characteristic of each lectin. Immature and mature secretory gran- ules were labelled with WGA, SBA, PNA, and lightly with UEA-I. Cis and intermediate cisternae of the Golgi apparatus were labelled with WGA, and trans cisternae with WGA and SBA.