Sample records for cell wall ultrastructure

  1. Ultrastructure of organic cell walls in Proterozoic microalgae

    Moczydlowska-Vidal, M.


    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.

    Koval, S F; Jarrell, K F


    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

    LI Beimei; ZHAO Guangjie


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

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

    Gritsch, Cristina Sanchis; Murphy, Richard J.


    • 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

    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.

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


    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


    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

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


    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

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


    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.

    Trentini, W C; Murray, R G


    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

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


    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.

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


    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

    Tanasković Irena


    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

    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

    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



    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

    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

    Ewa Kupidłowska


    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


    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

    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

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


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

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

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


    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



    [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.

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


    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

    Komatsu, Setsuko; Yanagawa, Yuki


    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


    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

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


    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

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


    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

    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)


    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.

    Sylwia Fudali


    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

    Levin, David E.


    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

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


    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

    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

    Marcel PARVU


    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

    Vidaurre, Danielle; Bonetta, Dario


    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

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


    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

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


    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)

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


    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



    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

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


    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

    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

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


    We introduce a general theoretical framework to study the shape dynamics of actively growing and remodeling surfaces. Using this framework we develop a physical model for growing bacterial cell walls and study the interplay of cell shape with the dynamics of growth and constriction. The model allows us to derive constraints on cell wall mechanical energy based on the observed dynamics of cell shape. We predict that exponential growth in cell size requires a constant amount of cell wall energy...

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

    M. Čiamporová


    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

    Banerjee, Shiladitya; Dinner, Aaron R


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

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

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


    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

    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.

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


    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.

    Ferri, S; Sesso, A


    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

    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

    Svedström, Kirsi


    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.

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


    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

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


    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.

    Glassy, M C; Ferrone, S


    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

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


    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

    Levin, David E.


    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

    Nozawa, Y.; Kitajima, Y.


    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)

    YIN JiangXia; WANG HongMei; RACEY Paul; ZHANG ShuYi


    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)

    RACEY; Paul


    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

    E Redondo


    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.

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


    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

    Lesage, Guillaume; Bussey, Howard


    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

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


    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

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


    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?

    Cosgrove, D. J.


    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

    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

    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

    Eduardo F. Bondan


    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

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


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

  10. Glycoprotein component of plant cell walls

    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

    Blumreisinger, Maria; Meindl, Doris; Loos, Eckhard


    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.


    Castejón O


    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.

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


    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

    San Clemente, Hélène; Jamet, Elisabeth


    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 ( presently contains 2170 proteins and ESTs identified experimentally i...

  15. Safranine fluorescent staining of wood cell walls.

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


    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.

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


    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.

    Narang, H K


    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

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


    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

    Hai-shui LUO


    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

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


    Cell wall proteins are essential constituents of plant cell walls; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface. The application of proteomic approaches to the cell wall compartment raises important questions: are there technical problems specific to cell wall proteomics? What kinds of proteins can be found in Arabidopsis walls? Are some of them unexpected? What sort of post-translation...

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

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


    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

    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

    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

    Cosgrove, D. J.


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

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

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth


    Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell wa...

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

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


    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

    许彦枝; 邹慧儒; 王小玲; 刘世正; 王永军


    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

    Daniel J. Cosgrove


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

  9. Refractive index of plant cell walls

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


    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

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


    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.

    Suwalak, Sakol; Voravuthikunchai, Supayang P


    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

    Ptashnyk, Mariya; Seguin, Brian


    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.

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


    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

    Bogdan Wróbel


    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

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


    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.

    Оlena M. Nedukha


    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

    Niklowitz, W.J.


    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

    Tenhaken, Raimund


    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.

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


    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

    M. Miko


    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

    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


    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.

    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


    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

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


    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

    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


    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

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


    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

    Arias Covadonga R


    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

    Mayura Paul


    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

    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.

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


    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

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


    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)

    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


    Artemios Michael BOSABALIDIS


    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

    LI GuanShi; YIN YaJun; LI Yan; ZHONG Zheng


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

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

    CHEN Jian-hui; ZHOU Wei


    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.

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


    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

    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

    Maria Elzbieta Sobaniec-Lotowska; Dariusz Marek Lebensztejn


    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

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


    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

    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

    Sacchi L.


    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.


    Artemios Michael BOSABALIDIS


    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.

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


    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

    Ebine, Kazuo; Ueda, Takashi


    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

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


    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

    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.

    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.

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


    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

    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.

    Liu, Longzhou; Free, Stephen J


    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.

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


    Plant cell walls provide stability and protection to plant cells. During growth and development the composition of cell walls changes, but provides enough strength to withstand the turgor of the cells. Hence, cell walls are highly flexible and diverse in nature. These characteristics are important during root growth, as plant roots consist of radial patterns of cells that have diverse functions and that are at different developmental stages along the growth axis. Young stem cell daughters undergo a series of rapid cell divisions, during which new cell walls are formed that are highly dynamic, and that support rapid anisotropic cell expansion. Once the cells have differentiated, the walls of specific cell types need to comply with and support different cell functions. For example, a newly formed root hair needs to be able to break through the surrounding soil, while endodermal cells modify their walls at distinct positions to form Casparian strips between them. Hence, the cell walls are modified and rebuilt while cells transit through different developmental stages. In addition, the cell walls of roots readjust to their environment to support growth and to maximize nutrient uptake. Many of these modifications are likely driven by different developmental and stress signaling pathways. However, our understanding of how such pathways affect cell wall modifications and what enzymes are involved remain largely unknown. In this review we aim to compile data linking cell wall content and re-modeling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes. PMID:27582757

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


    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.

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


    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

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


    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

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


    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.

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


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

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

    Jianjun Zhang


    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.

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


    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

    Gonneau, Martine; Höfte, Herman; Vernhettes, Samantha


    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.

    Cosgrove, Daniel J


    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

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


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

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

    Usha Agrawal


    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.

    Nierzwicki-Bauer, S A; Aulfinger, H


    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

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


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

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

    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

    Sankaran, Ashwin Karthik


    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

    Li, Zhuo


    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.

    Martine eGonneau; Herman eHöfte; Samantha eVernhettes


    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

    李登科; 赵立东; 孙建和; 刘慧占; 杨仕明


    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

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


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

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



    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.

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


    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

    Cosgrove, D. J.


    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

    Bellincampi, Daniela; Cervone, Felice; Lionetti, Vincenzo


    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

    Daniela eBellincampi; Felice eCervone; Vincenzo eLionetti


    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

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


    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.

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


    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.

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


    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.

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


    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

    陈文列; 陈金富; 钟秀容; 梁平; 林炜


    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


    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

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


    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

    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

    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

    Nühse, Thomas S.


    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

    Cosgrove, D. J.


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

  6. Anthocyanins influence tannin-cell wall interactions.

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


    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.

    McQueen-Mason, S; Cosgrove, D J


    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?

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


    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

    M. Malatesta


    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.

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


    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

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


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

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

    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

    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

    Hilz, H


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

    Georgeault Sonia


    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.

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


    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

    Christiernin, Maria


    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.

    Schlaeppi, J M; Karamata, D


    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.

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


    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.

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


    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.

    Yoshimi, Akira; Miyazawa, Ken; Abe, Keietsu


    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

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


    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.

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


    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.

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


    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.

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


    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

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


    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

    Fernando, Dinesh


    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

    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

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


    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

    Cosgrove, D. J.


    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

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


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

  12. Hemicellulose biosynthesis and degradation in tobacco cell walls

    Compier, M.G.M.


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

  13. Characterising the cellulose synthase complexes of cell walls

    Mansoori Zangir, N.


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

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



    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

    Kouki eYoshida


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

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

    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


    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



    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

    Huan-Zhong Wang; Richard A.Dixon


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

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

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


    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

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


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

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


    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

    Kohorn, Bruce D


    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.

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


    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.

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


    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

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


    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

    Abdoulaye J.S. Bakhoum


    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

    Balestrini, Raffaella; Bonfante, Paola


    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.

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


    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

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


    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.

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


    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)

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


    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

    Jean-Claude Mollet


    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.

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


    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.

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


    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

    Dare, Kiley; Ibba, Michael


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

    梅俊学; 沈颂东; 姜明; 费修绠


    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

    Lima D.U.


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

  18. Transformation of Abdominal Wall Endometriosis to Clear Cell Carcinoma

    Maria Paula Ruiz; Darryl Lewis Wallace; Matthew Thomas Connell


    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

    Timmers, J.F.P.


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

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


    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

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


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

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

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


    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

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


    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.

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


    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

    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

    Canut Hervé


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

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

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


    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

    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))


    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.

    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

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


    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).

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


    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.

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


    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

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


    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.

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


    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


    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

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


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

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

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


    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.

    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

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


    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

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


    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

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


    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

    Mitsuo Suga


    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

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


    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

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


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

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

    Gabriel Paës


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

  6. Synthesis and Application of Plant Cell Wall Oligogalactans

    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

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


    The battle between plants and microbes is evolutionarily ancient, highly complex, and often co-dependent. A primary challenge for microbes is to breach the physical barrier of host cell walls whilst avoiding detection by the plant's immune receptors. While some receptors sense conserved microbial...... 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.

    Dichtl, Karl; Samantaray, Sweta; Wagener, Johannes


    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

    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

    Krzysztof Korta


    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.