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Sample records for sanguinalis mesophyll cells

  1. Metabolomic Responses of Guard Cells and Mesophyll Cells to Bicarbonate.

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    Biswapriya B Misra

    Full Text Available Anthropogenic CO2 presently at 400 ppm is expected to reach 550 ppm in 2050, an increment expected to affect plant growth and productivity. Paired stomatal guard cells (GCs are the gate-way for water, CO2, and pathogen, while mesophyll cells (MCs represent the bulk cell-type of green leaves mainly for photosynthesis. We used the two different cell types, i.e., GCs and MCs from canola (Brassica napus to profile metabolomic changes upon increased CO2 through supplementation with bicarbonate (HCO3-. Two metabolomics platforms enabled quantification of 268 metabolites in a time-course study to reveal short-term responses. The HCO3- responsive metabolomes of the cell types differed in their responsiveness. The MCs demonstrated increased amino acids, phenylpropanoids, redox metabolites, auxins and cytokinins, all of which were decreased in GCs in response to HCO3-. In addition, the GCs showed differential increases of primary C-metabolites, N-metabolites (e.g., purines and amino acids, and defense-responsive pathways (e.g., alkaloids, phenolics, and flavonoids as compared to the MCs, indicating differential C/N homeostasis in the cell-types. The metabolomics results provide insights into plant responses and crop productivity under future climatic changes where elevated CO2 conditions are to take center-stage.

  2. Metabolomic Responses of Guard Cells and Mesophyll Cells to Bicarbonate.

    Science.gov (United States)

    Misra, Biswapriya B; de Armas, Evaldo; Tong, Zhaohui; Chen, Sixue

    2015-01-01

    Anthropogenic CO2 presently at 400 ppm is expected to reach 550 ppm in 2050, an increment expected to affect plant growth and productivity. Paired stomatal guard cells (GCs) are the gate-way for water, CO2, and pathogen, while mesophyll cells (MCs) represent the bulk cell-type of green leaves mainly for photosynthesis. We used the two different cell types, i.e., GCs and MCs from canola (Brassica napus) to profile metabolomic changes upon increased CO2 through supplementation with bicarbonate (HCO3-). Two metabolomics platforms enabled quantification of 268 metabolites in a time-course study to reveal short-term responses. The HCO3- responsive metabolomes of the cell types differed in their responsiveness. The MCs demonstrated increased amino acids, phenylpropanoids, redox metabolites, auxins and cytokinins, all of which were decreased in GCs in response to HCO3-. In addition, the GCs showed differential increases of primary C-metabolites, N-metabolites (e.g., purines and amino acids), and defense-responsive pathways (e.g., alkaloids, phenolics, and flavonoids) as compared to the MCs, indicating differential C/N homeostasis in the cell-types. The metabolomics results provide insights into plant responses and crop productivity under future climatic changes where elevated CO2 conditions are to take center-stage.

  3. Programmed Cell Death Progresses Differentially in Epidermal and Mesophyll Cells of Lily Petals.

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    Hiroko Mochizuki-Kawai

    Full Text Available In the petals of some species of flowers, programmed cell death (PCD begins earlier in mesophyll cells than in epidermal cells. However, PCD progression in each cell type has not been characterized in detail. We separately constructed a time course of biochemical signs and expression patterns of PCD-associated genes in epidermal and mesophyll cells in Lilium cv. Yelloween petals. Before visible signs of senescence could be observed, we found signs of PCD, including DNA degradation and decreased protein content in mesophyll cells only. In these cells, the total proteinase activity increased on the day after anthesis. Within 3 days after anthesis, the protein content decreased by 61.8%, and 22.8% of mesophyll cells was lost. A second peak of proteinase activity was observed on day 6, and the number of mesophyll cells decreased again from days 4 to 7. These biochemical and morphological results suggest that PCD progressed in steps during flower life in the mesophyll cells. PCD began in epidermal cells on day 5, in temporal synchrony with the time course of visible senescence. In the mesophyll cells, the KDEL-tailed cysteine proteinase (LoCYP and S1/P1 nuclease (LoNUC genes were upregulated before petal wilting, earlier than in epidermal cells. In contrast, relative to that in the mesophyll cells, the expression of the SAG12 cysteine proteinase homolog (LoSAG12 drastically increased in epidermal cells in the final stage of senescence. These results suggest that multiple PCD-associated genes differentially contribute to the time lag of PCD progression between epidermal and mesophyll cells of lily petals.

  4. Differential positioning of chloroplasts in C4 mesophyll and bundle sheath cells.

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    Maai, Eri; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2011-08-01

    Chloroplast photorelocation movement is extensively studied in C3 but not C4 plants. C4 plants have 2 types of photosynthetic cells: mesophyll and bundle sheath cells. Mesophyll chloroplasts are randomly distributed along cell walls, whereas bundle sheath chloroplasts are located close to the vascular tissues or mesophyll cells depending on the plant species. The cell-specific C 4 chloroplast arrangement is established during cell maturation, and is maintained throughout the life of the cell. However, only mesophyll chloroplasts can change their positions in response to environmental stresses. The migration pattern is unique to C4 plants and differs from that of C3 chloroplasts. In this mini-review, we highlight the cell-specific disposition of chloroplasts in C4 plants and discuss the possible physiological significances.

  5. Phytosulfokine, Sulfated Peptides that Induce the Proliferation of Single Mesophyll Cells of Asparagus officinalis L

    National Research Council Canada - National Science Library

    Yoshikatsu Matsubayashi; Youji Sakagami

    1996-01-01

    ...). No known plant hormones have been able to substitute for CM. To quantify the mitogenic activity of CM, we examined conditions for the assay system using mechanically dispersed mesophyll cells of Asparagus officinalis L...

  6. FUNCTION OF MALATDEHYDROGENASE COMPLEX OF MAIZE MESOPHYLL AND BUNDLE SHEATH CELLS UNDER SALT STRESS CONDITION

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    Еprintsev А.Т.

    2006-12-01

    Full Text Available Salt-induced changes in malatdehydrogenase system activity make the essential contribution to cell adaptation to stress condition. The enzyme systems of C4-plants are most interesting due to their ability for adaptation to environment conditions. The role of separate components of malatdehydrogenase complex of mesophyll and bundle sheath cells of corn in formation of adaptive reaction in stressful conditions is investigated in presented work.The activation of all enzymes of malatdehydrogenase system and the subsequent decrease in their activity was observed in mesophyll durring the first stage of adaptation to salt influence. In bundle sheath cells such parameters are differed from control less essentially. Fast accumulation of piruvate in cells and malate in both investigated tissues was induced. The further salinity led to falling of concentration this intermediate. The concentration of piruvate was below control level, and it was raised by the end of an exposition.The results show that sodium chloride causes induction of Krebs-cycle in mesophyll and bundle sheath cells of corn and intensification of Hatch-Slack cycle. The described differences in function malatdehydrogenase systems of mesophyll and bundle sheath cells of leaves of corn under salinity mainly consist of the activity of enzymes of a studied complex in bundle sheath cells is subject to the minimal changes in comparison with mesophyll. Role of this enzymesystem in mechanisms of adaptive reaction of various tissues of corn to salt stress is discussed.

  7. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

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    Yuan, Hengguang; Hu, Shanglian; Huang, Peng; Song, Hua; Wang, Kan; Ruan, Jing; He, Rong; Cui, Daxiang

    2011-12-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  8. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

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    Huang Peng

    2011-01-01

    Full Text Available Abstract Herein we are the first to report that single-walled carbon nanotubes (SWCNTs exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  9. Cytochemical characterization of plastidal inclusions in Abutilon mosaic-infected Malva parviflora mesophyll cells.

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    Jeske, H; Werz, G

    1980-10-15

    Electron microscopy of plastids from mesophyll cells of Malva parviflora infected with the Abutilon mosaic virus revealed elongated "chains of pearls" with subunits of 7.5 nm in diameter. Paracrystalline inclusions of the chains of pearls studied by means of cytochemical techniques gave evidence of the presence of DNA.

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

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

    2016-08-01

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

  11. Distinct abscisic acid signaling pathways for modulation of guard cell versus mesophyll cell potassium channels revealed by expression studies in Xenopus laevis oocytes

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    Sutton, F.; Paul, S. S.; Wang, X. Q.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

    2000-01-01

    Regulation of guard cell ion transport by abscisic acid (ABA) and in particular ABA inhibition of a guard cell inward K(+) current (I(Kin)) is well documented. However, little is known concerning ABA effects on ion transport in other plant cell types. Here we applied patch clamp techniques to mesophyll cell protoplasts of fava bean (Vicia faba cv Long Pod) plants and demonstrated ABA inhibition of an outward K(+) current (I(Kout)). When mesophyll cell protoplast mRNA (mesophyll mRNA) was expressed in Xenopus laevis oocytes, I(Kout) was generated that displayed similar properties to I(Kout) observed from direct analysis of mesophyll cell protoplasts. I(Kout) expressed by mesophyll mRNA-injected oocytes was inhibited by ABA, indicating that the ABA signal transduction pathway observed in mesophyll cells was preserved in the frog oocytes. Co-injection of oocytes with guard cell protoplast mRNA and cRNA for KAT1, an inward K(+) channel expressed in guard cells, resulted in I(Kin) that was similarly inhibited by ABA. However, oocytes co-injected with mesophyll mRNA and KAT1 cRNA produced I(Kin) that was not inhibited by ABA. These results demonstrate that the mesophyll-encoded signaling mechanism could not substitute for the guard cell pathway. These findings indicate that mesophyll cells and guard cells use distinct and different receptor types and/or signal transduction pathways in ABA regulation of K(+) channels.

  12. Salt-mediated changes in leaf mesophyll cells of Lycopersicon esculentum Mill. plants

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    Magdalena Gapinska

    2014-09-01

    Full Text Available Five-week-old tomato plants (Lycopersicon esculentum cv. Perkoz grown in pots containing garden soil in a growth chamber were submitted to 50 or 150 mM NaCl for 1 h, 2 and 5 days. Tomato leaf anatomy generally did not change after short time salinity, except 5-day-treatment with 150 mM NaCl, where changed cell shape (shrunk and deformed simultaneously with increased volume of intercellular spaces (IS were observed. Although leaf hydration (H depleted only 1 h after 150 mM NaCl treatment both salt concentrations generated two coexisting populations of salt-affected mesophyll cells: (i slightly-affected (Sl-A which showed incipient plasmolysis or slightly changed shapes, and (ii severely-affected (Sv-A which showed severe plasmolysis; serious deformation of cell shape or disorganization including cell degeneration. In Sl-A cells salinity changed location and shape of chloroplasts which were: more rounded, with oversized starch grains (SG (2d or more flat (5d. Salt-mediated changes were becoming more distinguished and pronounced with length of 150 mM NaCl treatment. The amount of salt-affected cells was changing during the experiment and depended on the salt concentration. In 50 mM-treated plants salt-affected cells appeared 1 h after treatment (~40% and raised up to 78% on 2nd day, however the population of Sl-A cells dominated. In 150 mM NaCl-treated plants the percentage of affected cells raised during the experiment from 75% to 99%. Firstly Sl-A cells dominated, but on the 5th day the majority was Sv-A. Salt-affected cells were distributed quite evenly in palisade or spongy mesophyll, except 2 d after treatment with 50 mM NaCl, when their number was higher in the palisade mesophyll. Sv-A cells in the spongy mesophyll were located mostly near the bundle while in the palisade mesophyll more irregularly. Different susceptibility of cells to salt stress might be the consequence of an unequal distribution of osmotic stress and subsequent ionic

  13. Signal function of cytokinin 6-benzylaminopurine in the reaction of Triticum aestivum L. mesophyll cells to hyperthermia

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    M. M. Musienko

    2014-12-01

    Full Text Available The signaling effect of 6-benzylaminopurine (BAP on leaf mesophyll cells of Triticum aestivum L. under hyperthermic conditions was studied­. It was found that BAP regulated photosynthetic pigment, hydrogen peroxide content and activity of antioxidant enzymes, namely superoxide dismutase, ascorbate peroxidase and catalase under high-temperature conditions. The additive effect of BAP and high temperature on the activation of cell antioxidant systems was demonstrated. BAP regulated reducing processes in mesophyll leaf cells under high-temperature conditions.

  14. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  15. Clinorotation affects mesophyll photosynthetic cells in leaves of pea seedlings.

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    Adamchuk, N I

    1998-07-01

    Experiments with autotrophs in altered gravity condition have a grate significant for development of space biology. The main results of investigation in the photosynthetic apparatus state under microgravity condition have based on the experiments with maturity plants and their differentiated cells. The structural and functional organization of photosynthetic cells in seedlings is poor understandable still. Along with chloroplasts preserving a native membrane system in palisade parenchyma cells of the 29-day pea plant leaves in microgravity, chloroplasts with fribly packed or damaged granae, whose thylakoids appeared as vesicles with an electrontransparent content, were also observed. The investigation of preceding process induced these effects have a sense. That is why, the goal of our experiments was to perform the study of a structural organization of the photosynthetic cells of 3-d pair of pea seedlings leaves under the influence of clinorotation.

  16. The production and efflux of 4-aminobutyrate in isolated mesophyll cells.

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    Chung, I; Bown, A W; Shelp, B J

    1992-06-01

    The pathway of 4-aminobutyric acid (GABA) production and efflux was investigated in suspensions of mesophyll cells isolated from asparagus (Asparagus sprengeri Regel) cladophylls. Analysis of free amino acids demonstrated that, on a molar basis, GABA represented 11.4, 19, and 6.5% of the xylem sap, intact cladophyll tissue, and isolated mesophyll cells, respectively. l-Glu, a GABA precursor, was abundant in intact cladophylls and isolated cells but not in xylem sap. When cells were incubated with l-[U-(14)C]Glu, intracellular GABA contained less than 10% of the radioactivity found in intracellular Glu. However, GABA in the medium contained 78% of the radioactivity found in extracellular l-Glu metabolites. Incubation with l-[1-(14)C]Glu resulted in the appearance of unlabeled GABA, demonstrating its production through decarboxylation at carbon 1. GABA released to the medium from cells incubated with l-[U-(14)C]Glu had a specific activity of 18 nanocuries per nanomole, whereas GABA remaining in the cell had a specific activity of 2.25 x 10(-1) nanocuries per nanomole. In the presence of exogenous l-Glu, amino acid analysis and cell volume measurements indicated intracellular Ala and GABA concentrations of 4.2 and 1.4 millimolar, respectively. In the medium, however, the corresponding concentrations were 2 and 57 micromolar. The data indicate that l-Glu entering the cell is decarboxylated to GABA, and that specific and passive efflux is from this pool of recently synthesized GABA and not from a previously synthesized unlabeled pool of GABA.

  17. RNA processing body (P-body) dynamics in mesophyll protoplasts re-initiating cell division.

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    Bhullar, Dilbag S; Sheahan, Michael B; Rose, Ray J

    2017-07-01

    The ability of plants to regenerate lies in the capacity of differentiated cells to reprogram and re-enter the cell cycle. Reprogramming of cells requires changes in chromatin organisation and gene expression. However, there has been less focus on changes at the post transcription level. We have investigated P-bodies, sites of post transcriptional gene regulation, in plant cell reprogramming in cultured mesophyll protoplasts; by using a YFP-VARICOSE (YFP-VCSc) translational fusion. We showed an early increase in P-body number and volume, followed by a decline, then a subsequent continued increase in P-body number and volume as cell division was initiated and cell proliferation continued. We infer that plant P-bodies have a role to play in reprogramming the mature cell and re-initiating the cell division cycle. The timing of the first phase is consistent with the degredation of messages no longer required, as the cell transits to the division state, and may also be linked to the stress response associated with division induction in cultured cells. The subsequent increase in P-body formation, with partitioning to the daughter cells during the division process, suggests a role in the cell cycle and its re-initiation in daughter cells. P-bodies were shown to be mobile in the cytoplasm and show actin-based motility which facilitates their post-transcriptional role and partitioning to daughter cells.

  18. Differential gene expression for Curvularia eragrostidis pathogenic incidence in crabgrass (Digitaria sanguinalis revealed by cDNA-AFLP analysis.

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    Jianshu Wang

    Full Text Available Gene expression profiles of Digitaria sanguinalis infected by Curvularia eragrostidis strain QZ-2000 at two concentrations of conidia and two dew durations were analyzed by cDNA amplified fragment length polymorphisms (cDNA-AFLP. Inoculum strength was more determinant of gene expression than dew duration. A total of 256 primer combinations were used for selective amplification and 1214 transcript-derived fragments (TDFs were selected for their differential expression. Of these, 518 up-regulated differentially expressed TDFs were identified. Forty-six differential cDNA fragments were chosen to be cloned and 35 of them were successfully cloned and sequenced, of which 25 were homologous to genes of known function according to the GenBank database. Only 6 genes were up-regulated in Curvularia eragrostidis-inoculated D. sanguinalis, with functions involved in signal transduction, energy metabolism, cell growth and development, stress responses, abscisic acid biosynthesis and response. It appears that a few pathways may be important parts of the pathogenic strategy of C. eragrostidis strain QZ-2000 on D. sanguinalis. Our study provides the fundamentals to further study the pathogenic mechanism, screen for optimal C. eragrostidis strains as potential mycoherbicide and apply this product to control D. sanguinalis.

  19. Differential gene expression for Curvularia eragrostidis pathogenic incidence in crabgrass (Digitaria sanguinalis) revealed by cDNA-AFLP analysis.

    Science.gov (United States)

    Wang, Jianshu; Wang, Xuemin; Yuan, Bohua; Qiang, Sheng

    2013-01-01

    Gene expression profiles of Digitaria sanguinalis infected by Curvularia eragrostidis strain QZ-2000 at two concentrations of conidia and two dew durations were analyzed by cDNA amplified fragment length polymorphisms (cDNA-AFLP). Inoculum strength was more determinant of gene expression than dew duration. A total of 256 primer combinations were used for selective amplification and 1214 transcript-derived fragments (TDFs) were selected for their differential expression. Of these, 518 up-regulated differentially expressed TDFs were identified. Forty-six differential cDNA fragments were chosen to be cloned and 35 of them were successfully cloned and sequenced, of which 25 were homologous to genes of known function according to the GenBank database. Only 6 genes were up-regulated in Curvularia eragrostidis-inoculated D. sanguinalis, with functions involved in signal transduction, energy metabolism, cell growth and development, stress responses, abscisic acid biosynthesis and response. It appears that a few pathways may be important parts of the pathogenic strategy of C. eragrostidis strain QZ-2000 on D. sanguinalis. Our study provides the fundamentals to further study the pathogenic mechanism, screen for optimal C. eragrostidis strains as potential mycoherbicide and apply this product to control D. sanguinalis.

  20. Effects of High Temperature Stress on Microscopic and Ultrastructural Characteristics of Mesophyll Cells in Flag Leaves of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gui-lian; CHEN Li-yun; ZHANG Shun-tang; ZHENG Hua; LIU Guo-hua

    2009-01-01

    The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines (a thermo- sensitive line 4628 and a thermo-resistant line 996) under high temperature stress (37°C during 8:00-17:00 and 30°C during 17:00-8:00) were investigated using an optical and a transmission electron microscopy. The membrane permeability and malondialdehyde content increased under the high temperature stress, and the increase of both variables was greater in the line 4628 than in the line 996. Under the high temperature stress, the line 996 showed tightly arranged mesophyll cells in flag leaves, fully developed vascular bundles and some closed stomata, whereas the line 4628 suffered from injury because of undeveloped vascular bundles, loosely arranged mesophyll cells and opened stomata. The mesophyll cells in flag leaves of the line 4628 were severely damaged under the high temperature stress, i.e. the chloroplast envelope became blurred, the grana thylakoid layer was arranged loosely and irregularly, the stroma layer disappeared, many osmiophilic granules appeared within the chloroplast, the outer membrane of mitochondria and the nucleus disintegrated and became blurred, the nucleolus disappeared, and much fibrillar-granular materials appeared within the nucleus. In contrast, the mesophyll cells in flag leaves of the line 996 maintained an intact ultrastructure under the high temperature stress. From these results, it is suggested that the ultrastructural modification of the cell membrane system is the primary plant response to high temperature stress and can be used as an index to evaluate the crop heat tolerance.

  1. Possible association of actin filaments with chloroplasts of spinach mesophyll cells in vivo and in vitro.

    Science.gov (United States)

    Kumatani, T; Sakurai-Ozato, N; Miyawaki, N; Yokota, E; Shimmen, T; Terashima, I; Takagi, S

    2006-11-01

    In palisade mesophyll cells of spinach (Spinacia oleracea L.) kept under low-intensity white light, chloroplasts were apparently immobile and seemed to be surrounded by fine bundles of actin filaments. High-intensity blue light induced actin-dependent chloroplast movement concomitant with the appearance of a couple of long, straight bundles of actin filaments in each cell, whereas high-intensity red light was essentially ineffective in inducing these responses. The actin organization observed under low-intensity white light has been postulated to function in anchoring chloroplasts at proper intracellular positions through direct interaction with the chloroplasts. Intact chloroplasts, which retained their outer envelopes, were isolated after homogenization of leaves and Percoll centrifugation. No endogenous actin was detected by immunoblotting in the final intact-chloroplast fraction prepared from the leaves kept under low-intensity white light or in darkness. In cosedimentation assays with exogenously added skeletal muscle filamentous actin, however, actin was detected in the intact-chloroplast fraction precipitated after low-speed centrifugation. The association of actin with chloroplasts was apparently dependent on incubation time and chloroplast density. After partial disruption of the outer envelope of isolated chloroplasts by treatment with trypsin, actin was no longer coprecipitated. The results suggest that chloroplasts in spinach leaves can directly interact with actin, and that this interaction may be involved in the regulation of intracellular positioning of chloroplasts.

  2. Pico-projector-based optical sectioning microscopy for 3D chlorophyll fluorescence imaging of mesophyll cells

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    Chen, Szu-Yu; Hsu, Yu John; Yeh, Chia-Hua; Chen, S.-Wei; Chung, Chien-Han

    2015-03-01

    A pico-projector-based optical sectioning microscope (POSM) was constructed using a pico-projector to generate structured illumination patterns. A net rate of 5.8 × 106 pixel/s and sub-micron spatial resolution in three-dimensions (3D) were achieved. Based on the pico-projector’s flexibility in pattern generation, the characteristics of POSM with different modulation periods and at different imaging depths were measured and discussed. With the application of different modulation periods, 3D chlorophyll fluorescence imaging of mesophyll cells was carried out in freshly plucked leaves of four species without sectioning or staining. For each leaf, an average penetration depth of 120 μm was achieved. Increasing the modulation period along with the increment of imaging depth, optical sectioning images can be obtained with a compromise between the axial resolution and signal-to-noise ratio. After ∼30 min imaging on the same area, photodamage was hardly observed. Taking the advantages of high speed and low damages of POSM, the investigation of the dynamic fluorescence responses to temperature changes was performed under three different treatment temperatures. The three embedded blue, green and red light-emitting diode light sources were applied to observe the responses of the leaves with different wavelength excitation.

  3. Ultrastructural changes in chloroplasts of mesophyll cells of chlorotic and prematurely yellowed leaves of Betula pendula Rothr

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    Krystyna Przybył

    2011-04-01

    Full Text Available The ultrastructure of chloroplasts was studied in mesophyll cells of the leaves of silver birch (Betula pendula showing interveinal chlorosis or premature yellowing, in comparison with leaves without symptoms or exhibiting symptoms of natural senescence. The leaves were collected between May 26 to June 7 and additionally in the September 10-12 from the upper part of the crown, from increments of the past four years. No major difference in ultrastructure of chloroplasts was found between spongy and palisade mesophyll cells. The following senescencerelated changes were observed in chloroplasts of prematurely yellowed leaves and showing inteveinal chlorosis: reduced chloroplast size, degeneration of the membrane systems of thylakoids and increased electron density of plastoglobuli. The most electron dark globules (lipid droplets were found together with starch grains in cells of spongy mesophyll of leaves showing interveinal chlorosis. Abnormal, spherical and rounded chloroplasts with electron-dark inside of thylakoids or the electron-dark stroma between thylakoids were found only in yellowed and chlorotic leaves in spring.

  4. Kinetics of Ca2+- and ATP-dependent, voltage-controlled anion conductance in the plasma membrane of mesophyll cells of Pisum sativum

    NARCIS (Netherlands)

    Elzenga, J.T.M.; van Volkenburgh, E.

    1997-01-01

    Whole-cell patch-clamp techniques were used to measure anion currents through the plasma membrane of protoplasts of mesophyll cells of expanding pea (Pisum sativum L.) leaves. Voltage-induced changes of the currents could be modelled with single exponential activation and deactivation kinetics. The

  5. Blue light-dependent changes in loosely bound calcium in Arabidopsis mesophyll cells: an X-ray microanalysis study.

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    Łabuz, Justyna; Samardakiewicz, Sławomir; Hermanowicz, Paweł; Wyroba, Elżbieta; Pilarska, Maria; Gabryś, Halina

    2016-06-01

    Calcium is involved in the signal transduction pathway from phototropins, the blue light photoreceptor kinases which mediate chloroplast movements. The chloroplast accumulation response in low light is controlled by both phot1 and phot2, while only phot2 is involved in avoidance movement induced by strong light. Phototropins elevate cytosolic Ca(2+) after activation by blue light. In higher plants, both types of chloroplast responses depend on Ca(2+), and internal calcium stores seem to be crucial for these processes. Yet, the calcium signatures generated after the perception of blue light by phototropins are not well understood. To characterize the localization of calcium in Arabidopsis mesophyll cells, loosely bound (exchangeable) Ca(2+) was precipitated with potassium pyroantimonate and analyzed by transmission electron microscopy followed by energy-dispersive X-ray microanalysis. In dark-adapted wild-type Arabidopsis leaves, calcium precipitates were observed at the cell wall, where they formed spherical structures. After strong blue light irradiation, calcium at the apoplast prevailed, and bigger, multilayer precipitates were found. Spherical calcium precipitates were also detected at the tonoplast. After red light treatment as a control, the precipitates at the cell wall were smaller and less numerous. In the phot2 and phot1phot2 mutants, calcium patterns were different from those of wild-type plants. In both mutants, no elevation of calcium after blue light treatment was observed at the cell periphery (including the cell wall and a fragment of cytoplasm). This result confirms the involvement of phototropin2 in the regulation of Ca(2+) homeostasis in mesophyll cells.

  6. A new mechanism for the regulation of stomatal aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping; Outlaw, W.H. Jr.; Smith, B.G.; Freed, G.A. [Florida State Univ., Tallahassee, FL (United States)

    1997-05-01

    At various times after pulse-labeling broad bean (Vicia faba L.) leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents, whereas those from rinsed peels contained only symplastic contents. Sucrose (Suc)-specific radioactivity peaked (111 GBq mol{sup -1}) in palisade cells at 20 min. In contrast, the {sup 14}C content and Suc-specific radioactivity were very low in guard cells for 20 min, implying little CO, incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum Suc-specific radioactivity (204 GBq mol{sup -1}) and a high Suc influx rate (0.05 pmol stoma{sup -1} min{sup -1}). These and other comparisons implied the presence of (a) multiple Suc pools in mesophyll cells, M a localized mesophyll-apoplast region that exchanges with phloem and stomata, and mesophyll-derived Suc in guard-cell walls sufficient to diminish stomatal opening by approximately 3 pm. Factors expected to enhance Suc accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and N high apoplastic Suc concentration, which is elevated when mesophyll Suc efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal aperture size by this previously unrecognized mechanism. 50 refs., 9 figs.

  7. A New Mechanism for the Regulation of Stomatal Aperture Size in Intact Leaves (Accumulation of Mesophyll-Derived Sucrose in the Guard-Cell Wall of Vicia faba).

    Science.gov (United States)

    Lu, P.; Outlaw Jr, W. H.; Smith, B. G.; Freed, G. A.

    1997-05-01

    At various times after pulse-labeling broad bean (Vicia faba L.) leaflets with 14CO2, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents, whereas those from rinsed peels contained only symplastic contents. Sucrose (Suc)-specific radioactivity peaked (111 GBq mol-1) in palisade cells at 20 min. In contrast, the 14C content and Sucspecific radioactivity were very low in guard cells for 20 min, implying little CO2 incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum Suc-specific radioactivity (204 GBq mol-1) and a high Suc influx rate (0.05 pmol stoma-1 min-1). These and other comparisons implied the presence of (a) multiple Suc pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived Suc in guard-cell walls sufficient to diminish stomatal opening by approximately 3 [mu]m. Factors expected to enhance Suc accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic Suc concentration, which is elevated when mesophyll Suc efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal aperture size by this previously unrecognized mechanism.

  8. Intracellular position of mitochondria and chloroplasts in bundle sheath and mesophyll cells of C3 grasses in relation to photorespiratory CO2 loss

    Directory of Open Access Journals (Sweden)

    Yuto Hatakeyama

    2016-10-01

    Full Text Available In C3 plants, photosynthetic efficiency is reduced by photorespiration. A part of CO2 fixed during photosynthesis in chloroplasts is lost from mitochondria during photorespiration by decarboxylation of glycine by glycine decarboxylase (GDC. Thus, the intracellular position of mitochondria in photosynthetic cells is critical to the rate of photorespiratory CO2 loss. We investigated the intracellular position of mitochondria in parenchyma sheath (PS and mesophyll cells of 10 C3 grasses from 3 subfamilies (Ehrhartoideae, Panicoideae, and Pooideae by immunostaining for GDC and light and electron microscopic observation. Immunostaining suggested that many mitochondria were located in the inner half of PS cells and on the vacuole side of chloroplasts in mesophyll cells. Organelle quantification showed that 62–75% of PS mitochondria were located in the inner half of cells, and 62–78% of PS chloroplasts were in the outer half. In mesophyll cells, 61–92% of mitochondria were positioned on the vacuole side of chloroplasts and stromules. In PS cells, such location would reduce the loss of photorespiratory CO2 by lengthening the path of CO2 diffusion and allow more efficient fixation of CO2 from intercellular spaces. In mesophyll cells, it would facilitate scavenging by chloroplasts of photorespiratory CO2 released from mitochondria. Our data suggest that the PS cells of C3 grasses have already acquired an initial structure leading to proto-Kranz and further C3–C4 intermediate anatomy. We also found that in the Pooideae, organelle positioning in PS cells on the phloem side resembles that in mesophyll cells.

  9. Cell wall matrix polysaccharide distribution and cortical microtubule organization: two factors controlling mesophyll cell morphogenesis in land plants.

    Science.gov (United States)

    Sotiriou, P; Giannoutsou, E; Panteris, E; Apostolakos, P; Galatis, B

    2016-03-01

    This work investigates the involvement of local differentiation of cell wall matrix polysaccharides and the role of microtubules in the morphogenesis of mesophyll cells (MCs) of three types (lobed, branched and palisade) in the dicotyledon Vigna sinensis and the fern Asplenium nidus. Homogalacturonan (HGA) epitopes recognized by the 2F4, JIM5 and JIM7 antibodies and callose were immunolocalized in hand-made leaf sections. Callose was also stained with aniline blue. We studied microtubule organization by tubulin immunofluorescence and transmission electron microscopy. In both plants, the matrix cell wall polysaccharide distribution underwent definite changes during MC differentiation. Callose constantly defined the sites of MC contacts. The 2F4 HGA epitope in V. sinensis first appeared in MC contacts but gradually moved towards the cell wall regions facing the intercellular spaces, while in A. nidus it was initially localized at the cell walls delimiting the intercellular spaces, but finally shifted to MC contacts. In V. sinensis, the JIM5 and JIM7 HGA epitopes initially marked the cell walls delimiting the intercellular spaces and gradually shifted in MC contacts, while in A. nidus they constantly enriched MC contacts. In all MC types examined, the cortical microtubules played a crucial role in their morphogenesis. In particular, in palisade MCs, cortical microtubule helices, by controlling cellulose microfibril orientation, forced these MCs to acquire a truncated cone-like shape. Unexpectedly in V. sinensis, the differentiation of colchicine-affected MCs deviated completely, since they developed a cell wall ingrowth labyrinth, becoming transfer-like cells. The results of this work and previous studies on Zea mays (Giannoutsou et al., Annals of Botany 2013; 112: : 1067-1081) revealed highly controlled local cell wall matrix differentiation in MCs of species belonging to different plant groups. This, in coordination with microtubule-dependent cellulose microfibril

  10. Death of mitochondria during programmed cell death of leaf mesophyll cells.

    Science.gov (United States)

    Selga, Tūrs; Selga, Maija; Pāvila, Vineta

    2005-12-01

    The role of plant mitochondria in the programmed cell death (PCD) is widely discussed. However, spectrum and sequence of mitochondrial structural changes during different types of PCD in leaves are poorly described. Pea, cucumber and rye plants were grown under controlled growing conditions. A part of them were sprinkled with ethylene releaser to accelerate cell death. During yellowing the palisade parenchyma mitochondria were attracted to nuclear envelope. Mitochondrial matrix became electron translucent. Mitochondria entered vacuole by invagination of tonoplast and formed multivesicular bodies. Ethephon treatment increased the frequency of sticking of mitochondria to the nuclear envelope or chloroplasts and peroxisomes. Mitochondria divided by different mechanisms and became enclosed in Golgi and ER derived authopagic vacuoles or in the central vacuole. Several fold increase of the diameter of cristae became typical. In all cases mitochondria were attached to nuclear envelope. It can be considered as structural mechanism of promoting of PCD.

  11. A lower content of de-methylesterified homogalacturonan improves enzymatic cell separation and isolation of mesophyll protoplasts in Arabidopsis.

    Science.gov (United States)

    Lionetti, Vincenzo; Cervone, Felice; De Lorenzo, Giulia

    2015-04-01

    Cell adhesion occurs primarily at the level of middle lamella which is mainly composed by pectin polysaccharides. These can be degraded by cell wall degrading enzymes (CWDEs) during developmental processes to allow a controlled separation of plant cells. Extensive cell wall degradation by CWDEs with consequent cell separation is performed when protoplasts are isolated from plant tissues by using mixtures of CWDEs. We have evaluated whether modification of pectin affects cell separation and protoplast isolation. Arabidopsis plants overexpressing the pectin methylesterase inhibitors AtPMEI-1 or AtPMEI-2, and Arabidopsis pme3 plants, mutated in the gene encoding pectin methylesterase 3, showed an increased efficiency of isolation of viable mesophyll protoplasts as compared with Wild Type Columbia-0 plants. The release of protoplasts was correlated with the reduced level of long stretches of de-methylesterified homogalacturonan (HGA) present in these plants. Response to elicitation, cell wall regeneration and efficiency of transfection in protoplasts from transgenic plants was comparable to those of wild type protoplasts.

  12. Mesophyll cells of C4 plants have fewer chloroplasts than those of closely related C3 plants.

    Science.gov (United States)

    Stata, Matt; Sage, Tammy L; Rennie, Troy D; Khoshravesh, Roxana; Sultmanis, Stefanie; Khaikin, Yannay; Ludwig, Martha; Sage, Rowan F

    2014-11-01

    The evolution of C(4) photosynthesis from C(3) ancestors eliminates ribulose bisphosphate carboxylation in the mesophyll (M) cell chloroplast while activating phosphoenolpyruvate (PEP) carboxylation in the cytosol. These changes may lead to fewer chloroplasts and different chloroplast positioning within M cells. To evaluate these possibilities, we compared chloroplast number, size and position in M cells of closely related C(3), C(3) -C(4) intermediate and C(4) species from 12 lineages of C(4) evolution. All C(3) species had more chloroplasts per M cell area than their C(4) relatives in high-light growth conditions. C(3) species also had higher chloroplast coverage of the M cell periphery than C(4) species, particularly opposite intercellular air spaces. In M cells from 10 of the 12 C(4) lineages, a greater fraction of the chloroplast envelope was pulled away from the plasmalemma in the C(4) species than their C(3) relatives. C(3) -C(4) intermediate species generally exhibited similar patterns as their C(3) relatives. We interpret these results to reflect adaptive shifts that facilitate efficient C(4) function by enhancing diffusive access to the site of primary carbon fixation in the cytosol. Fewer chloroplasts in C(4) M cells would also reduce shading of the bundle sheath chloroplasts, which also generate energy required by C(4) photosynthesis.

  13. Effects of Temperature Acclimation Pretreatment on the Ultrastructure of Mesophyll Cells in Young Grape Plants (Vitis vinifera L. cv. Jingxiu) Under Cross-Temperature Stresses

    Institute of Scientific and Technical Information of China (English)

    Jun-Huan ZHANG; Wei-Dong HUANG; Yue-Ping LIU; Qiu-Hong PAN

    2005-01-01

    Leaves from annual young grape plants (Vitis vinifera L. cv. Jingxiu) were used as experimentalmaterials. The ultrastructural characteristics of mesophyll cells in chilling-treated plants after heat acclima-tion (HA) and in heat-treated plants after cold acclimation (CA) were observed and compared using trans-mission electron microscopy. The results showed that slight injury appeared in the ultrastructure of meso-phyll cells after either HA (38℃ for 10 h) or CA (8℃ for 2.5 d), but the tolerance to subsequent extremetemperature stress was remarkably improved by HA or CA pretreatment. The increases in membrane perme-ability and malondialdehyde concentration under chilling (0℃) or heat (45℃) stress were markedly inhib-ited by HA or CA pretreatment. The mesophyll cells of plants not pretreated with HA were markedly dam-aged following chilling stress. The chloroplasts appeared irregular in shape, the arrangement of the stromalamellae was disordered, and no starch granules were present. The cristae of the mitochondria were dis-rupted and became empty. The nucleus became irregular in shape and the nuclear membrane was digested.In contrast, the mesophyll cells of HA-pretreated plants maintained an intact ultrastructure under chillingstress. The mesophyll cells of control plants were also severely damaged under heat stress. The chloroplastbecame round in shape, the stroma lamellae became swollen, and the contents of vacuoles formed clumps.In the case of mitochondria of control plants subjected to heat stress, the outer envelope was digested andthe cristae were disrupted and became many small vesicles. Compared with cellular organelles in controlplants, those in CA plant cells always maintained an integrated state during whole heat stress, except for thechloroplasts, which became round in shape after 10 h heat stress. From these data, we suggest that thestability of mesophyll cells under chilling stress can be increased by HA pretreatment. Similarly, CA pretreat

  14. An investigation into the roles of photosynthesis and respiration in h efflux from aerated suspensions of asparagus mesophyll cells.

    Science.gov (United States)

    Bown, A W

    1982-09-01

    Aerated and stirred suspensions of mechanically isolated Asparagus sprengeri Regel mesophyll cells were used to investigate the roles of respiration and photosynthesis in net H(+) efflux. Rates varied between 0.12 and 1.99 nanomoles H(+) per 10(6) cells per minute or 3 and 40 nanomoles H(+) per milligram chlorophyll per minute. The mean rate of H(+) efflux was 10% greater in the dark. 3-(3,4-Dichlorophenyl)-l,l-dimethylurea, an inhibitor of noncyclic photophosphorylation, did not inhibit H(+) efflux from illuminated cells. Bubbling with N(2) or addition of oligomycin, an inhibitor of mitochondrial ATP production, resulted in rapid and virtually complete inhibition of H(+) efflux in light or dark. In the absence of aeration, H(+) efflux came to a halt but resumed with aeration or illumination. When aeration was switched to CO(2)-free air, rates of H(+) efflux were reduced 43% in the dark and 57% in the light. Oligomycin eliminated dark CO(2) fixation but not photosynthetic CO(2) fixation. It is suggested that H(+) efflux is dependent on respiration and dark CO(2) fixation, but independent of photosynthesis.

  15. Proton/l-Glutamate Symport and the Regulation of Intracellular pH in Isolated Mesophyll Cells.

    Science.gov (United States)

    Snedden, W A; Chung, I; Pauls, R H; Bown, A W

    1992-06-01

    Addition of l-[U-(14)C]glutamate to a suspension of mechanically isolated asparagus (Asparagus sprengeri Regel) mesophyll cells results in (a) alkalinization of the medium, (b) uptake of l-[U-(14)C]glutamate, and (c) efflux of [(14)C]4-aminobutyrate, a product of glutamate decarboxylation. All three phenomena were eliminated by treatment with 1 millimolar aminooxyacetate. In vitro glutamate decarboxylase (GAD) assays showed that (a) 2 millimolar aminooxyacetate eliminated enzyme activity, (b) activity was pyridoxal phosphate-dependent, and (c) activity exhibited a sharp pH optimum at 6.0 that decreased to 20% of optimal activity at pH 5.0 and 7.0. Addition of 1.5 millimolar sodium butyrate or sodium acetate to cell suspensions caused immediate alkalinization of the medium followed by a resumption of acidification of the medium at a rate approximately double the initial rate. The data indicate that (a) continued H(+)/l-glutamate contransport is dependent upon GAD activity, (b) the pH-dependent properties of GAD are consistent with a role in a metabolic pH-stat, and (c) the regulation of intracellular pH during H(+)/l-Glu symport may involve both H(+) consumption during 4-aminobutyrate production and ATP-driven H(+) efflux.

  16. Plastidic Phosphoglucose Isomerase Is an Important Determinant of Starch Accumulation in Mesophyll Cells, Growth, Photosynthetic Capacity, and Biosynthesis of Plastidic Cytokinins in Arabidopsis

    OpenAIRE

    Abdellatif Bahaji; Ángela M Sánchez-López; Nuria De Diego; Muñoz, Francisco J.; Edurne Baroja-Fernández; Jun Li; Adriana Ricarte-Bermejo; Marouane Baslam; Iker Aranjuelo; Goizeder Almagro; Humplík, Jan F.; Ondřej Novák; Lukáš Spíchal; Karel Doležal; Javier Pozueta-Romero

    2015-01-01

    Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP). In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of th...

  17. Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

    Directory of Open Access Journals (Sweden)

    Andreia Michelle Smith-Moritz

    2015-08-01

    Full Text Available The CELLULOSE SYNTHASE-LIKE F6 (CslF6 gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG, a cell wall polysaccharide that is hypothesized to be a tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to test the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of three day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell was of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.

  18. Light-dependent intracellular positioning of mitochondria in Arabidopsis thaliana mesophyll cells.

    Science.gov (United States)

    Islam, Md Sayeedul; Niwa, Yasuo; Takagi, Shingo

    2009-06-01

    Mitochondria, the power house of the cell, are one of the most dynamic cell organelles. Although there are several reports on actin- or microtubule-dependent movement of mitochondria in plant cells, intracellular positioning and motility of mitochondria under different light conditions remain open questions. Mitochondria were visualized in living Arabidopsis thaliana leaf cells using green fluorescent protein fused to a mitochondrion-targeting signal. In darkness, mitochondria were distributed randomly in palisade cells. In contrast, mitochondria accumulated along the periclinal walls, similar to the accumulation response of chloroplasts, when treated with weak blue light (470 nm, 4 micromol m(-2) s(-1)). Under strong blue light (100 micromol m(-2) s(-1)), mitochondria occupied the anticlinal positions similar to the avoidance response of chloroplasts and nuclei. While strong red light (660 nm, 100 micromol m(-2) s(-1)) induced the accumulation of mitochondria along the inner periclinal walls, green light exhibited little effect on the distribution of mitochondria. In addition, the mode of movement of individual mitochondria along the outer periclinal walls under different light conditions was precisely analyzed by time-lapse fluorescence microscopy. A gradual increase in the number of static mitochondria located in the vicinity of chloroplasts with a time period of blue light illumination clearly demonstrated the accumulation response of mitochondria. Light-induced co-localization of mitochondria with chloroplasts strongly suggested their mutual metabolic interactions. This is the first characterization of the light-dependent redistribution of mitochondria in plant cells.

  19. Stomatal crypts may facilitate diffusion of CO(2) to adaxial mesophyll cells in thick sclerophylls.

    Science.gov (United States)

    Hassiotou, Foteini; Evans, John R; Ludwig, Martha; Veneklaas, Erik J

    2009-11-01

    In some plants, stomata are exclusively located in epidermal depressions called crypts. It has been argued that crypts function to reduce transpiration; however, the occurrence of crypts in species from both arid and wet environments suggests that crypts may play another role. The genus Banksia was chosen to examine quantitative relationships between crypt morphology and leaf structural and physiological traits to gain insight into the functional significance of crypts. Crypt resistance to water vapour and CO(2) diffusion was calculated by treating crypts as an additional boundary layer partially covering one leaf surface. Gas exchange measurements of polypropylene meshes confirmed the validity of this approach. Stomatal resistance was calculated as leaf resistance minus calculated crypt resistance. Stomata contributed significantly more than crypts to leaf resistance. Crypt depth increased and accounted for an increasing proportion of leaf resistance in species with greater leaf thickness and leaf dry mass per area. All Banksia species examined with leaves thicker than 0.6 mm had their stomata in deep crypts. We propose that crypts function to facilitate CO(2) diffusion from the abaxial surface to adaxial palisade cells in thick leaves. This and other possible functions of stomatal crypts, including a role in water use, are discussed.

  20. IRON UPTAKE BY LEAF MESOPHYLL-CELLS - THE ROLE OF THE PLASMA MEMBRANE-BOUND FERRIC-CHELATE REDUCTASE

    NARCIS (Netherlands)

    BRUGGEMANN, W; MAASKANTEL, K; MOOG, PR

    1993-01-01

    The uptake of Fe-59 from FeCl3, ferric (Fe3+) citrate (FeCitr) and Fe3+-EDTA (FeEDTA) was studied in leaf mesophyll of Vigna unguiculata (L.) Walp. Uptake rates decreased in the order FeCl3>FeCitr much greater than FeEDTA, and uptake depended on an obligatory reduction step of Fe3+ to Fe2+, after wh

  1. Plastidic phosphoglucose isomerase is an important determinant of starch accumulation in mesophyll cells, growth, photosynthetic capacity, and biosynthesis of plastidic cytokinins in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Abdellatif Bahaji

    Full Text Available Phosphoglucose isomerase (PGI catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP. In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of the pPGI encoding gene, PGI1. Starch content in pgi1-3 source leaves was ca. 10-15% of that of wild type (WT leaves, which was similar to that of leaves of pgi1-2, a T-DNA insertion pPGI null mutant. Starch deficiency of pgi1 leaves could be reverted by the introduction of a sex1 null mutation impeding β-amylolytic starch breakdown. Although previous studies showed that starch granules of pgi1-2 leaves are restricted to both bundle sheath cells adjacent to the mesophyll and stomata guard cells, microscopy analyses carried out in this work revealed the presence of starch granules in the chloroplasts of pgi1-2 and pgi1-3 mesophyll cells. RT-PCR analyses showed high expression levels of plastidic and extra-plastidic β-amylase encoding genes in pgi1 leaves, which was accompanied by increased β-amylase activity. Both pgi1-2 and pgi1-3 mutants displayed slow growth and reduced photosynthetic capacity phenotypes even under continuous light conditions. Metabolic analyses revealed that the adenylate energy charge and the NAD(PH/NAD(P ratios in pgi1 leaves were lower than those of WT leaves. These analyses also revealed that the content of plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP-pathway derived cytokinins (CKs in pgi1 leaves were exceedingly lower than in WT leaves. Noteworthy, exogenous application of CKs largely reverted the low starch content phenotype of pgi1 leaves. The overall data show that pPGI is an important determinant of photosynthesis, energy

  2. Effects of potentially acidic air pollutants on the intracellular distribution and transport of plant growth regulators in mesophyll cells of leaves. Consequences on stress- and developmental physiology

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, H.; Pfanz, H.; Hartung, W.

    1987-07-11

    The influence of SO/sub 2/ on the intracellular distribution of abscisic acid (ABA) and indole-acetic acid (IAA) in mesophyll cells of Picea abies, Tsuga americana and Hordeum vulgare was investigated. The compartmentation of ABA and IAA depends on intracellular pH-gradients. The hydrophilic anions ABA and IAA are accumulated in the alkaline cell compartments cytosol and chloroplasts, which act as anion traps for weak acids. Uptake of sulfur dioxide into leaves leads to an acidification of alkaline cell compartments, thus decreasing intracellular pH-gradients. Consequently this results in an increased release of plant growth regulators from the cell interior into the apoplast. Therefore the target cells of plant hormones i.e. meristems and stomates are exposed to altered hormone concentrations. Obviously this influences the regulation of cellular metabolism plant development and growth.

  3. The Mechanistic Basis of Internal Conductance: A Theoretical Analysis of Mesophyll Cell Photosynthesis and CO2 Diffusion1[W][OA

    Science.gov (United States)

    Tholen, Danny; Zhu, Xin-Guang

    2011-01-01

    Photosynthesis is limited by the conductance of carbon dioxide (CO2) from intercellular spaces to the sites of carboxylation. Although the concept of internal conductance (gi) has been known for over 50 years, shortcomings in the theoretical description of this process may have resulted in a limited understanding of the underlying mechanisms. To tackle this issue, we developed a three-dimensional reaction-diffusion model of photosynthesis in a typical C3 mesophyll cell that includes all major components of the CO2 diffusion pathway and associated reactions. Using this novel systems model, we systematically and quantitatively examined the mechanisms underlying gi. Our results identify the resistances of the cell wall and chloroplast envelope as the most significant limitations to photosynthesis. In addition, the concentration of carbonic anhydrase in the stroma may also be limiting for the photosynthetic rate. Our analysis demonstrated that higher levels of photorespiration increase the apparent resistance to CO2 diffusion, an effect that has thus far been ignored when determining gi. Finally, we show that outward bicarbonate leakage through the chloroplast envelope could contribute to the observed decrease in gi under elevated CO2. Our analysis suggests that physiological and anatomical features associated with gi have been evolutionarily fine-tuned to benefit CO2 diffusion and photosynthesis. The model presented here provides a novel theoretical framework to further analyze the mechanisms underlying diffusion processes in the mesophyll. PMID:21441385

  4. Influence of pH on the /sup 14/C-labelling pattern after photosynthesis of suspended leaf slices and isolated mesophyll cells from chenopodium album in NaH/sup 14/CO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, G.; Guenther, G. (Paedagogische Hochschule Karl Liebknecht, Potsdam (German Democratic Republic). Sektion Chemie/Biologie)

    1983-01-01

    Photosynthetic fixation of /sup 14/C from solutions of NaH/sup 14/CO/sub 3/ (at constant concentrations of free CO/sub 2/) by suspended leaf slices or isolated mesophyll cells from Chenopodium album is increased with increasing pH. Above all, the incorporation of radioactivity into amino acids and malate is stimulated. A direct uptake of HCO/sub 3/ ions and its fixation by PEP carboxylase is suggested. Isolated mesophyll cells showed at pH 7.3 a higher rate of photosynthesis than at pH 5.0.

  5. High-contrast three-dimensional imaging of the Arabidopsis leaf enables the analysis of cell dimensions in the epidermis and mesophyll

    Directory of Open Access Journals (Sweden)

    Granier Christine

    2010-07-01

    Full Text Available Abstract Background Despite the wide spread application of confocal and multiphoton laser scanning microscopy in plant biology, leaf phenotype assessment still relies on two-dimensional imaging with a limited appreciation of the cells' structural context and an inherent inaccuracy of cell measurements. Here, a successful procedure for the three-dimensional imaging and analysis of plant leaves is presented. Results The procedure was developed based on a range of developmental stages, from leaf initiation to senescence, of soil-grown Arabidopsis thaliana (L. Heynh. Rigorous clearing of tissues, made possible by enhanced leaf permeability to clearing agents, allowed the optical sectioning of the entire leaf thickness by both confocal and multiphoton microscopy. The superior image quality, in resolution and contrast, obtained by the latter technique enabled the three-dimensional visualisation of leaf morphology at the individual cell level, cell segmentation and the construction of structural models. Image analysis macros were developed to measure leaf thickness and tissue proportions, as well as to determine for the epidermis and all layers of mesophyll tissue, cell density, volume, length and width. For mesophyll tissue, the proportion of intercellular spaces and the surface areas of cells were also estimated. The performance of the procedure was demonstrated for the expanding 6th leaf of the Arabidopsis rosette. Furthermore, it was proven to be effective for leaves of another dicotyledon, apple (Malus domestica Borkh., which has a very different cellular organisation. Conclusions The pipeline for the three-dimensional imaging and analysis of plant leaves provides the means to include variables on internal tissues in leaf growth studies and the assessment of leaf phenotypes. It also allows the visualisation and quantification of alterations in leaf structure alongside changes in leaf functioning observed under environmental constraints. Data

  6. Expression of a ferredoxin-dependent glutamate synthase gene in mesophyll and vascular cells and functions of the enzyme in ammonium assimilation in Nicotiana tabacum (L.).

    Science.gov (United States)

    Feraud, Magali; Masclaux-Daubresse, Céline; Ferrario-Méry, Sylvie; Pageau, Karine; Lelandais, Maud; Ziegler, Christine; Leboeuf, Edouard; Jouglet, Tiphaine; Viret, Lauriane; Spampinato, Axelle; Paganelli, Vanina; Hammouda, Mounir Ben; Suzuki, Akira

    2005-11-01

    GLU1 encodes the major ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.1) in Arabidopsis thaliana (ecotype Columbia). With the aim of providing clues on the role of Fd-GOGAT, we analyzed the expression of Fd-GOGAT in tobacco (Nicotiana tabacum L. cv. Xanthi). The 5' flanking element of GLU1 directed the expression of the uidA reporter gene in the palisade and spongy parenchyma of mesophyll, in the phloem cells of vascular tissue and in the roots of tobacco. White light, red light or sucrose induced GUS expression in the dark-grown seedlings in a pattern similar to the GLU1 mRNA accumulation in Arabidopsis. The levels of GLU2 mRNA encoding the second Fd-GOGAT and NADH-glutamate synthase (NADH-GOGAT, EC 1.4.1.14) were not affected by light. Both in the light and in darkness, (15)NH4(+) was incorporated into [5-(15)N]glutamine and [2-(15)N]glutamate by glutamine synthetase (GS, EC 6.3.1.2) and Fd-GOGAT in leaf disks of transgenic tobacco expressing antisense Fd-GOGAT mRNA and in wild-type tobacco. In the light, low level of Fd-glutamate synthase limited the [2-(15)N]glutamate synthesis in transgenic leaf disks. The efficient dark labeling of [2-(15)N]glutamate in the antisense transgenic tobacco leaves indicates that the remaining Fd-GOGAT (15-20% of the wild-type activity) was not the main limiting factor in the dark ammonium assimilation. The antisense tobacco under high CO2 contained glutamine, glutamate, asparagine and aspartate as the bulk of the nitrogen carriers in leaves (62.5%), roots (69.9%) and phloem exudates (53.2%). The levels of glutamate, asparagine and aspartate in the transgenic phloem exudates were similar to the wild-type levels while the glutamine level increased. The proportion of these amino acids remained unchanged in the roots of the transgenic plants. Expression of GLU1 in mesophyll cells implies that Fd-GOGAT assimilates photorespiratory and primary ammonium. GLU1 expression in vascular cells indicates that Fd-GOGAT provides

  7. Alterations in the sugar metabolism and in the vacuolar system of mesophyll cells contribute to the desiccation tolerance of Haberlea rhodopensis ecotypes.

    Science.gov (United States)

    Georgieva, K; Rapparini, F; Bertazza, G; Mihailova, G; Sárvári, É; Solti, Á; Keresztes, Á

    2017-01-01

    Haberlea rhodopensis belongs to the small group of resurrection plants having the unique ability to survive desiccation to air dry state retaining most of its chlorophyll content and then resume normal function upon rehydration. It prefers the shady valleys and northward facing slopes of limestone ridges in mountain zones with high average humidity. Nevertheless, it can be found rarely on rocks directly exposed to the sunlight, without the coverage of the canopy. In the present study, we follow the alterations in the subcellular organization of mesophyll cells and sugar metabolism upon desiccation of shade and sun H. rhodopensis plants. Composition and content of soluble carbohydrates during desiccation and rehydration were different in plants grown below the trees or on the sunny rocks. Sucrose, however, was dominating in both ecotypes. The amount of starch grains in chloroplasts was inversely related to that of sugars. Concomitantly with these changes, the number of vacuoles was multiplied in the cells. This can be explained by the development of small (secondary) vacuoles peripherally in the cytoplasm, rather than by the fragmentation of the single vacuole, proposed earlier in the literature. Accordingly, the centripetal movement of chloroplasts and other organelles may be a result of the dynamic changes in the vacuolar system. Upon rehydration, the inner vacuoles enlarged and the organelles returned to their normal position.

  8. Interaction of Plant Epicuticular Waxes and Extracellular Esterases of Curvularia eragrostidis during Infection of Digitaria sanguinalis and Festuca arundinacea by the Fungus

    Directory of Open Access Journals (Sweden)

    Lang-Lai Xu

    2006-09-01

    Full Text Available Curvularia eragrostidis, a causal agent of head blight on the weed (Digitariasanguinalis, did not cause disease on the turfgrass Festuca arundinacea. Differentextracellular esterase isoenzymes were detected in saprophytic and parasitic phases duringthe fungal germination. The epicuticular waxes of D. sanguinalis were more efficient toinduce the secretion of esterases from the fungus than that of F. arundinacea, but were morerapidly degraded by the fungal enzymes. Component analysis indicated that the epicuticularwaxes from D. sanguinalis were mostly composed of alcohols, with 54.3% being 9,12-Octadecadien-1-ol. The main component of F arundinacea waxes was alkyl compounds,with 49.8% being olefin, 9-Tricosence. More long-chained esters were found in D.sanguinalis waxes, which were easier to be digested than those in F. arundinacea waxes byextreacellular esterases of the fungus. Epicuticular waxes play a role in varyingpathogenicity of C. eragrostidis on D. sanguinalis and F arundinacea.

  9. Isolation of mesophyll protoplasts from mature leaves of soybeans.

    Science.gov (United States)

    Lin, W

    1983-12-01

    A procedure based on a combined cellulase-Pectolyase Y-23 enzyme digestion and metrizamide-sorbitol gradient purification protocol was developed for isolating mesophyll protoplasts from mature leaves of soybean (Glycine max L. Merr.). Based on chlorophyll content, this procedure results in a 10 to 15% protoplast yield from fully expanded mature leaves and a 20 to 30% yield from young (expanding) leaves within 3 hours. Isolated protoplasts displayed high rates of HCO(3) (-)-dependent photosynthesis; greater than 75 micromoles O(2) evolved per milligram chlorophyll per hour at 25 degrees C. This photosynthetic rate is comparable to that of mesophyll cells isolated mechanically from the same leaves.

  10. Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. A new mechanism for the regulation of stomatal-aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba L.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, P.; Outlaw, W.H. Jr.; Smith, B.G.; Freed, G.A.

    1996-12-31

    At various times after pulse labeling Vicia faba L. leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents whereas those from rinsed peels contained only cytoplastic contents. Sucrose specific radioactivity peaked in palisade cells, 111 GBq{center_dot}mol{sup {minus}1}, at 20 min. In contrast, the {sup 14}C content and sucrose specific radioactivity were very low in guard cells for 20 min, implying little CO{sub 2} incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum sucrose specific radioactivity and a high sucrose influx rate. These and other comparisons implied the presence of (a) multiple sucrose pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived sucrose in guard-cell walls sufficient to diminish stomatal opening by {approximately} 4 {micro}m. Factors expected to enhance sucrose accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic sucrose concentration, which is elevated when mesophyll-sucrose efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal-aperture size by this previously unrecognized mechanism.

  11. Isolation and culture of daylily mesophyll protoplasts.

    Science.gov (United States)

    Ling, J T; Sauve, R J

    1995-12-01

    Mesophyll protoplasts were isolated from leaf tissues of a diploid daylily (Hemerocallisx'Red Magic') by enzymatic digestion with a solution containing 0.5% Pectolyase Y-23, 0.1% Cellulase R-10, 0.1% Driselase, 0.6 M sorbitol and half-strength MS inorganic salts. When cultured on MS medium supplemented with 0.5 mg/l NAA and 0.5 mg/l BA, the protoplasts underwent sustained division to produce multicellular colonies. The optimal plating density for cell division was 0.5 × 10(5) protoplasts/ml. The highest plating efficiency was obtained in cultures grown in media solidified with 0.2% Gelrite. Under these conditions, formation of colonies occurred from 14% of cultured protoplasts. Calli were recovered from 9 colonies only after the cultures were treated with a conditioned medium. Intact plants were regenerated from protoplast-derived calli through organogenesis.

  12. Leaf architecture and direction of incident light influence mesophyll fluorescence profiles.

    Science.gov (United States)

    Johnson, Daniel M; Smith, William K; Vogelmann, Thomas C; Brodersen, Craig R

    2005-09-01

    Light propagation and distribution inside leaves have been recognized as important processes influencing photosynthesis. Monochromatic light absorption across the mesophyll was measured using chlorophyll fluorescence generated from illumination of the cut edge (epi-illumination), as well as the adaxial or abaxial surfaces of the leaf. Species were selected that had basic leaf types: laminar leaf with adaxial palisade layer (Rhododendron catawbiense), needle with palisade (Abies fraseri), and needle without palisade (Picea rubens). Fluorescence was more evenly distributed across the mesophyll for adaxially illuminated leaves with a palisade cell layer, as well as for the needles (cylindrical) without palisade, when compared to fluorescence generated by abaxial illumination. Moreover, fluorescence from green light illumination remained high across the mesophyll of adaxially illuminated R. catawbiense, indicating a possible influence of mesophyll structure on internal light distribution beyond that of chlorophyll levels. These data support the idea that light propagation within the mesophyll is associated with asymmetric mesophyll structure, in particular the presence of palisade cell layers. In addition, we propose that the evolution of a more cylindrical leaf form, such as found in conifer species, may be a structural solution to excessive sunlight that replaces the highly differentiated mesophyll found in most laminar-leaved species.

  13. 马唐对烟嘧磺隆的抗药性研究%Resistance of Digitaria sanguinalis to Nicosulfuron

    Institute of Scientific and Technical Information of China (English)

    张宏军; 王贵启; 刘学; 边全乐

    2013-01-01

    2008-2009年在我国东北、华北的6个省份烟嘧磺隆防效下降的玉米田块采集80个马唐种群,在可控温室中采用整株测定法对其进行抗性检测试验.结果表明,不同用药历史玉米田的马唐种群对烟嘧磺隆已经产生了不同程度的抗药性,其中有10个种群产生的抗药性较显著.%Whole - plant bioassays were conducted in 2008 -2009 under controlled greenhouse conditions to determine the response to nicosulfuron of 80 Digitaria sanguinalis populations collected from maize fields in 6 provinces of the North and Northeast of China where efficacy of the herbicide had been declining. D. sanguinalis populations with different herbicide exposure histories had different degrees of resistance to nicosulfuron; ten of the populations were highly resistant to the herbicide.

  14. PHANTASTICA regulates development of the adaxial mesophyll in Nicotiana leaves.

    Science.gov (United States)

    McHale, Neil A; Koning, Ross E

    2004-05-01

    Initiation and growth of leaf blades is oriented by an adaxial/abaxial axis aligned with the original axis of polarity in the leaf primordium. To investigate mechanisms regulating this process, we cloned the Nicotiana tabacum ortholog of PHANTASTICA (NTPHAN) and generated a series of antisense transgenics in N. sylvestris. We show that NSPHAN is expressed throughout emerging blade primordia in the wild type and becomes localized to the middle mesophyll in the expanding lamina. Antisense NSPHAN leaves show ectopic expression of NTH20, a class I KNOX gene. Juvenile transgenic leaves have normal adaxial/abaxial polarity and generate leaf blades in the normal position, but the adaxial mesophyll shows disorganized patterns of cell division, delayed maturation of palisade, and ectopic reinitiation of blade primordia along the midrib. Reversal of the phenotype with exogenous gibberellic acid suggests that NSPHAN, acting via KNOX repression, maintains determinacy in the expanding lamina and sustains the patterns of cell proliferation critical to palisade development.

  15. Culture of soybean mesophyll protoplasts in alginate beads.

    Science.gov (United States)

    Tricoli, D M; Hein, M B; Carnes, M G

    1986-10-01

    Mesophyll protoplasts were isolated from leaves of 10 day old aseptically grown soybean seedlings, or from surface disinfested leaves of 3 week old plants grown in environmental chambers. The protoplasts were encapsulated in 2mm diameter Ca alginate beads. Immobilized protoplasts were induced to divide by culturing in shaker flasks containing an actively growing soybean cell suspension. The feeder cell suspension supported the division of protoplasts independent of the protoplast density in the Ca alginate beads. At day 18 after encapsulation, the alginate matrix was dissolved, releasing viable callus colonies. The feeder cell suspension obviated plating of protoplasts at high density which is usually required for subsequent cell division and colony development. Since the protoplasts were embedded at low density, the cell colonies were derived from single cells.

  16. Effect of Enhanced UV-B Radiation on Arabidopsis Mesophyll Cell Protein%增强UV-B辐射对拟南芥叶肉细胞蛋白的影响

    Institute of Scientific and Technical Information of China (English)

    魏小丽; 郑娜; 李晓阳; 韩榕

    2013-01-01

    Four-week-old wild-type Arabidopsis seedlings ( Columbia-O) was treated using different doses of UV-B radiation,the protein in the mesophyll cells was extracted using acetone precipitation and TCA-acetone,then Arabidopsis mesophyllcellular protein content and composition of the different intensity of UV-B radiation response were analyzed.The results showed that comparing two methods,the protein content of the TCA-acetone extract is relatively higher,which was more suitable for the analysis of enhanced UV-B radiation on Arabidopsis mesophyll cell protein; The changes of protein contents by two extraction methods showed the same trend,along with the increasing of UV-B radiation dose,the protein content increased first and then reduced,B2 group reached a maximum.In addition,the number of protein bands and expression has taken place significant change,the most obvious changes were also in the middle dose treatment group ( B2) ,both new bands and disappearance bands.This may be due to the Arabidopsis thaliana can activate some of its own resistance gene expressions and induce resistance protein by low doses of UV-B radiation,and thus resist the damage of UV-B; however,when subjected to high doses of UV-B radiation,damage their own protein synthesis pathway,and affect protein synthesis.%采用不同剂量的UV-B辐射处理4周龄的野生型拟南芥幼苗(Columbia-0),分别采用丙酮沉淀法和TCA-丙酮法提取其叶肉细胞中的蛋白质,进而研究分析拟南芥叶肉细胞中蛋白质的含量与组成对不同强度UV-B辐射的响应.结果显示,两种方法相比较,TCA-丙酮法所提取得到的蛋白含量相对较多,更适合于分析增强UV-B辐射对拟南芥叶肉细胞蛋白质的影响;而两种方法所提取得到的蛋白质含量的变化趋势相同,随着UV-B辐射剂量的增加,蛋白质含量呈先增加后减少的趋势,B2组达到了最大.此外,蛋白条带的数目和表达量也都发生了显著变化,同样

  17. Algunos aspectos de la biología y manejo de Digitaria sanguinalis (L. Scop. En asociación con el cultivo del arroz y otras especies adventicias Sorne aspects of the biology and rnanagernt of Digitaria sanguinalis (L. Scop. in rice crop and other weeds

    Directory of Open Access Journals (Sweden)

    Plaza T. Guido A.

    1998-12-01

    Full Text Available Para el cultivo del arroz en Colombia se reportan más de 70 especies de malezas que, por orden de competitividad biológica y económica, las malezas gramíneas son las de mayor afección al cultivo. Por su nocividad, las más importantes son: Echinochloa colonum (L. Link, Oryza sativa L. (arroz rojo, Cyperus rotundus L., Rottboellia cochinchinensis U., Fimbristylis annua (Alt. Riets, Murdania nudiflora (L. Brenan, y Digitaria sanguinalis (L. Scop. La ausencia de trabajos realizados sobre Digitaria sanguinalis (L Scop., dirigidos al conocimiento de sus aspectos biológicos, el aumento en la incidencia y agresividad de la especie en los cultivos de arroz y sorgo en la zona norte del Tolima, justificó la elaboración del presente estudio, para el cual se propusieron los siguientes objetivos: identificar aspectos de
    la biología y fenología, evaluar el banco de semillas y medir el efecto de la competencia de diferentes densidades de población de Digitaria sanguina lis (L. Scop. en los cultivos de arroz en Lérida, (Tolima. Los momentos de mayor suceptibilidad a la presencia de malezas en el cultivo del arroz fueron: a Germinación: D. sanguinalis completó esta fase en los tres primeros días después de humedecer el terreno, a diferencia de las semillas de arroz que requirieron dos días más. b Macollamiento: D. sanguinalis inició esta fase a los 20 días, a diferencia de las plantas de arroz que iniciaron a los 28 días. e Formación de Panícula: D. sanguina lis, la inició a los 65 días, a diferencia del arroz que inició a los 70 días. d Maduración de semillas: Las semillas de D. sanguinalis necesitaron 110 días para completar esta fase, las semillas de las plantas de arroz necesitaron 10 días más. D sanguinalis comenzó a liberar semillas a los 100 días aproximadamente. Mediante la emergencia de plántulas se
    logró estimar la composición del Banco de Semilla, obteniendo los mayores porcentajes de emergencia en

  18. Distinction between injury to tree leaves by ozone and mesophyll-feeding leafhoppers

    Energy Technology Data Exchange (ETDEWEB)

    Hibben, C.R.

    1969-06-01

    The phytotoxic effects of ozone and mesophyll-feeding leafhoppers were contrasted microscopically and histologically on leaves of Acer saccharum Marsh., Quercus rubra L., and Cornus florida L. Injuries induced by the two agents were readily distinguished by the differences in location, configuration, color, and size of the external symptoms, and by the characteristics of affected palisade parenchyma cells.

  19. Ontogenetic differences in mesophyll structure and chlorophyll distribution in Eucalyptus globulus ssp. globulus.

    Science.gov (United States)

    James, S A; Smith, W K; Vogelmann, T C

    1999-02-01

    Mesophyll structure has been associated with the photosynthetic performance of leaves via the regulation of internal light and CO(2) profiles. Differences in mesophyll structure and chlorophyll distribution within three ontogenetically different leaf types of Eucalyptus globulus ssp. globulus were investigated. Juvenile leaves are blue-grey in color, dorsiventral (adaxial palisade layer only), hypostomatous, and approximately horizontal in orientation. In contrast, adult leaves are dark green in color, isobilateral (adaxial and abaxial palisade), amphistomatous, and nearly vertical in orientation. The transitional leaf type has structural features that appear intermediate between the juvenile and adult leaves. The ratio of mesophyll cell surface area per unit leaf surface area (A(mes)/A) of juvenile leaves was maximum at the base of a single, adaxial palisade layer and declined through the spongy mesophyll. Chlorophyll a + b content showed a coincident pattern, while the chlorophyll a:b ratio declined linearly from the adaxial to abaxial epidermis. In comparison, the mesophyll of adult leaves had a bimodal distribution of A(mes)/A, with maxima occurring beneath both the adaxial and abaxial surfaces within the first layer of multiple palisade layers. The distribution of chlorophyll a + b content had a similar pattern, although the maximum ratio of chlorophyll a:b occurred immediately beneath the adaxial and abaxial epidermis. The matching distributions of A(mes)/A and chlorophyll provide further evidence that mesophyll structure may act to influence photosynthetic performance. These changes in internal leaf structure at different life stages of E. globulus may be an adaptation for increased xeromorphy under increasing light exposure experienced from the seedling to adult tree, similar to the characteristics reported for different species according to sunlight exposure and water availability within their native habitats.

  20. Angiosperms evolved a higher mesophyll surface area per volume to maximize exchange surface under a low CO2 world

    Science.gov (United States)

    Théroux-Rancourt, Guillaume; Mason Earles, J.; Gilbert, Matthew E.; Zwieniecki, Maciej A.; Boyce, C. Kevin; McElrone, Andrew; Brodersen, Craig

    2017-04-01

    Variation in leaf mesophyll structure strongly affects CO2 diffusion and photosynthetic rates. One key trait is the surface of mesophyll cells exposed to intercellular airspace (Sm) which increases mesophyll conductance. Consequently, Sm is a key control of CO2 diffusion among species and genotypes. Using Sm values from the literature (> 200 species with 500 data points) and from our high-resolution X-ray computed tomography (μCT) dataset (currently 117 species), Sm shows little variation from pteridophytes to early angiosperms, while eudicots show the greatest structural diversity. However, Sm increases with total thickness of the mesophyll. By considering the exposed surface of the mesophyll to the intercellular air space (IAS) on a leaf or mesophyll volume (Ames/V mes) rather than leaf area basis (Sm), we demonstrate that angiosperms, and most specifically commelinids and non-basal eudicots, have constructed leaves with more surface per volume, while gymnosperms keep a constant Ames/V mes ratio. Thus, this strong phylogenetic signal suggests that angiosperms have developed IAS properties favoring leaves with higher surface to volume ratio, trait that allowed for the potential of high productivity even as atmospheric CO2 declined over the Cenozoic.

  1. The paraveinal mesophyll of soybean leaves in relation to assimilate transfer and compartmentation : I. Ultrastructure and histochemistry during vegetative development.

    Science.gov (United States)

    Franceschi, V R; Giaquinta, R T

    1983-04-01

    The paraveinal mesophyll (PVM) is a unique and specialized, one-cell-thick tissue spanning the vascular bundles at the level of the phloem in soybean (Glycine max) (L.) Merr.) leaves. Its position within the leaf dictates that all photosynthate produced in the palisade and spongy mesophyll must pass through this specialized layer enroute to the phloem. Symplastic continuity, via plasmodesmata, exists between the PVM and bundle sheath, palisade parenchyma and spongy mesophyll. During leaf ontogeny the PVM is the first tissue to differentiate and at maturity these cells are six to eight times larger than other mesophyll cells, are highly vacuolate, and are interconnected by tubular arms. The PVM undergoes several unique structural and metabolic modifications during leaf development. The PVM cytoplasm, in vegetative plants, is dense, enriched in rough endoplasmic reticulum and dictyosomes, but contains few, small starch-free chloroplasts and few microbodies. Unlike the tonoplast of mesophyll cells, the tonoplast of the PVM is unusually thick and dense-staining. During leaf development the vacuoles of PVM cells accumulate a glycoprotein derived from the dictyosomes which reacts with the protein staining reagents, mercuric bromophenol blue and sulfaflavine, and is degraded by Pronase. Both the vacuolar material and tonoplast are also stained by phosphotungstic acid, which at low pH is relatively selective for glycoprotein. A unique role of the PVM in the transport and compartmentation of nitrogen reserves in soybeans is discussed.

  2. Effect of clinorotation on the leaf mesophyll structure and pigment content in Arabidopsis thaliana L. and Pisum sativum L.

    Science.gov (United States)

    Adamchuk, N I

    2004-07-01

    Properties of mesophyll cells and photosynthetic membranes of Arabidopsis thaliana (L.) Heynh. and Pisum sativum (L.) plants grown in a horizontal clinostat and in control conditions were compared. Obtained data have show that under clinorotation conditions seedlings have experienced the following cell morphology changes structural chloroplast rearrangement in palisade cells, pigment content alteration, and cell aging acceleration.

  3. Regeneration of plants from mesophyll protoplasts of the wild crucifer Eruca sativa Lam.

    Science.gov (United States)

    Sikdar, S R; Chatterjee, G; Das, S; Sen, S K

    1987-12-01

    Protoplasts isolated from mesophyll cells of Eruca sativa Lam., cultured on suitable medium, underwent sustained cell divisions to form calli. The plating efficiency was found to be 0.4%. The protoplast-derived calli subsequently produced plantlets through organogenesis (15.71%) and somatic embryogenesis (11.25%). Regenerated plants exhibited normal appearance. These results indicate potential to introgress desirable traits from this wild crucifer into important oilseed and cole Brassicas by protoplast fusion and hybrid recovery.

  4. Callus formation from leaf mesophyll protoplasts of Malus Xdomestica Borkh. cv. Greensleeves.

    Science.gov (United States)

    Doughty, S; Power, J B

    1988-05-01

    Large yields (1.85 × 10(7)/g.f.wt.) of viable protoplasts were obtained from leaves of axenic shoot cultures of Malus Xdomestica Borkh. cv. 'Greensleeves'. Protoplasts cultured in liquid or agarose semi-solidified KM8P medium underwent cell wall regeneration and colony formation.Protoplast-derived cell colonies developed to callus on semi-solid KM8 medium. This is the first report of callus formation from mesophyll protoplasts of apple.

  5. Potassium retention in leaf mesophyll as an element of salinity tissue tolerance in halophytes.

    Science.gov (United States)

    Percey, William J; Shabala, Lana; Wu, Qi; Su, Nana; Breadmore, Michael C; Guijt, Rosanne M; Bose, Jayakumar; Shabala, Sergey

    2016-12-01

    Soil salinity remains a major threat to global food security, and the progress in crop breeding for salinity stress tolerance may be achieved only by pyramiding key traits mediating plant adaptive responses to high amounts of dissolved salts in the rhizosphere. This task may be facilitated by studying natural variation in salinity tolerance among plant species and, specifically, exploring mechanisms of salinity tolerance in halophytes. The aim of this work was to establish the causal link between mesophyll ion transport activity and plant salt tolerance in a range of evolutionary contrasting halophyte and glycophyte species. Plants were grown under saline conditions in a glasshouse, followed by assessing their growth and photosynthetic performance. In a parallel set of experiments, net K(+) and H(+) transport across leaf mesophyll and their modulation by light were studied in control and salt-treated mesophyll segments using vibrating non-invasive ion selective microelectrode (the MIFE) technique. The reported results show that mesophyll cells in glycophyte species loses 2-6 fold more K(+) compared with their halophyte counterparts. This decline was reflected in a reduced maximum photochemical efficiency of photosystem II, chlorophyll content and growth observed in the glasshouse experiments. In addition to reduced K(+) efflux, the more tolerant species also exhibited reduced H(+) efflux, which is interpreted as an energy-saving strategy allowing more resources to be redirected towards plant growth. It is concluded that the ability of mesophyll to retain K(+) without a need to activate plasma membrane H(+)-ATPase is an essential component of salinity tolerance in halophytes and halophytic crop plants.

  6. Online CO2 and H2 O oxygen isotope fractionation allows estimation of mesophyll conductance in C4 plants, and reveals that mesophyll conductance decreases as leaves age in both C4 and C3 plants.

    Science.gov (United States)

    Barbour, Margaret M; Evans, John R; Simonin, Kevin A; von Caemmerer, Susanne

    2016-05-01

    Mesophyll conductance significantly, and variably, limits photosynthesis but we currently have no reliable method of measurement for C4 plants. An online oxygen isotope technique was developed to allow quantification of mesophyll conductance in C4 plants and to provide an alternative estimate in C3 plants. The technique is compared to an established carbon isotope method in three C3 species. Mesophyll conductance of C4 species was similar to that in the C3 species measured, and declined in both C4 and C3 species as leaves aged from fully expanded to senescing. In cotton leaves, simultaneous measurement of carbon and oxygen isotope discrimination allowed the partitioning of total conductance to the chloroplasts into cell wall and plasma membrane versus chloroplast membrane components, if CO2 was assumed to be isotopically equilibrated with cytosolic water, and the partitioning remained stable with leaf age. The oxygen isotope technique allowed estimation of mesophyll conductance in C4 plants and, when combined with well-established carbon isotope techniques, may provide additional information on mesophyll conductance in C3 plants.

  7. The research of cytokinin and hydrogen peroxide influence on the leaf mesophyll structure and morphometric parameters of winter wheat

    Directory of Open Access Journals (Sweden)

    Vladislav V. Zhuk

    2013-04-01

    Full Text Available The last leaf mesophyll structure of Triticum aestivumcv. ‘Tronka’which was grown in the field experiment conditions was investigated by the method of confocal laser scanning microscopy. The experiment plants were treated by BAP and Н 2О2 in booting phase. It is established that plant treatment didn’t effect on structure of leaf tissues but enhanced the functional ability of chloroplast pigment complexes. It has shown that influence of exogenous BAP enhanced chlorophyll autofluorescence, especially in palisade mesophyll cells, delayed aging of pigment complex. The action of exogenous mainly increased chlorophyll fluorescence of spongy mesophyll near stomata, but its influence was less significant than BAP. In winter wheat plants treated by BAP and Н 2О2 plant height and last leaf length enlarged. The plant treatment by BAP increased productivity of T. aestivumcv. ‘Tronka’ mainly by the cost of increasing of corns’ quantity in ear and corns’weight.

  8. Plants regenerated from mesophyll protoplasts of white mulberry

    Institute of Scientific and Technical Information of China (English)

    WEIZHIMING; ZHIHONGXU; 等

    1994-01-01

    Morus alba(white mulberry) mesophyll protoplasts were isolated from leaves of 30-45 day old sterile shoots,with protoplast yields of 2.5×107 g-1/F.W.after purification.The protoplasts were cultured in a modified K8P liquid medium containing 0.2mg/L 2,4-(2,4-Dichlorophenoxy acetic acid),1mg/L NAA(Naphthyl acetic acid) and 0.5mg/L BA(6-benzylaminopurine).A low plating density(5×104/ml) proved to be favourable to the division of protoplast-derived cells.The first division occurred 4 days after culture,and the division frequency reached 24% at 10 days.A number of cell colonies and microcalli formed in 6 weeks.The microcalli were transferred onto MSB medium with 0.5mg/L NAA and 0.5mg/L BA for further proliferation.Shoot formation was initiated when the calli of 3-4 mm in size were transferred onto MSB differentiation medium with 0.1mg/L NAA and 1mg/L BA.The frequency of shoot formation was 35%.The shoots of 4-5 cm in height were excised from the callus and rooted on half strength MS medium with 0.5 mg/L IBA and 0.1 mg/L BA.After transplantation into pots,the regenerated plants grew vigorously in the phytotron.

  9. A three-dimensional RNA motif in Potato spindle tuber viroid mediates trafficking from palisade mesophyll to spongy mesophyll in Nicotiana benthamiana.

    Science.gov (United States)

    Takeda, Ryuta; Petrov, Anton I; Leontis, Neocles B; Ding, Biao

    2011-01-01

    Cell-to-cell trafficking of RNA is an emerging biological principle that integrates systemic gene regulation, viral infection, antiviral response, and cell-to-cell communication. A key mechanistic question is how an RNA is specifically selected for trafficking from one type of cell into another type. Here, we report the identification of an RNA motif in Potato spindle tuber viroid (PSTVd) required for trafficking from palisade mesophyll to spongy mesophyll in Nicotiana benthamiana leaves. This motif, called loop 6, has the sequence 5'-CGA-3'...5'-GAC-3' flanked on both sides by cis Watson-Crick G/C and G/U wobble base pairs. We present a three-dimensional (3D) structural model of loop 6 that specifies all non-Watson-Crick base pair interactions, derived by isostericity-based sequence comparisons with 3D RNA motifs from the RNA x-ray crystal structure database. The model is supported by available chemical modification patterns, natural sequence conservation/variations in PSTVd isolates and related species, and functional characterization of all possible mutants for each of the loop 6 base pairs. Our findings and approaches have broad implications for studying the 3D RNA structural motifs mediating trafficking of diverse RNA species across specific cellular boundaries and for studying the structure-function relationships of RNA motifs in other biological processes.

  10. Dissection of miRNA pathways using arabidopsis mesophyll protoplasts.

    Science.gov (United States)

    Martinho, Cláudia; Confraria, Ana; Elias, Carlos Alexandre; Crozet, Pierre; Rubio-Somoza, Ignacio; Weigel, Detlef; Baena-González, Elena

    2015-02-01

    MicroRNAs (miRNAs) control gene expression mostly post-transcriptionally by guiding transcript cleavage and/or translational repression of complementary mRNA targets, thereby regulating developmental processes and stress responses. Despite the remarkable expansion of the field, the mechanisms underlying miRNA activity are not fully understood. In this article, we describe a transient expression system in Arabidopsis mesophyll protoplasts, which is highly amenable for the dissection of miRNA pathways. We show that by transiently overexpressing primary miRNAs and target mimics, we can manipulate miRNA levels and consequently impact on their targets. Furthermore, we developed a set of luciferase-based sensors for quantifying miRNA activity that respond specifically to both endogenous and overexpressed miRNAs and target mimics. We demonstrate that these miRNA sensors can be used to test the impact of putative components of the miRNA pathway on miRNA activity, as well as the impact of specific mutations, by either overexpression or the use of protoplasts from the corresponding mutants. We further show that our miRNA sensors can be used for investigating the effect of chemicals on miRNA activity. Our cell-based transient expression system is fast and easy to set up, and generates quantitative results, being a powerful tool for assaying miRNA activity in vivo.

  11. NaCl胁迫对5个引自北美的树种叶肉细胞超微结构的影响%Effect of NaCl stress on ultrastructure of mesophyll cells of five tree species introduced from North America

    Institute of Scientific and Technical Information of China (English)

    郝明灼; 马健; 梁有旺; 谭鹏鹏; 彭方仁

    2012-01-01

    为明确美国白蜡(Fraxinus americana L.)、茶条槭(Aceginnala Maxim.)、红桤木(Alnus rubra Bong.)、水紫树(Nyssa aquatica L.)和美国皂荚(Gleditsia triacanthos L.)5个引自北美的树种的耐盐性,采用水培方法、利用透射电镜技术对0(对照)、4和8 g·L-1 NaCl胁迫处理后5个树种1年生苗叶肉细胞超微结构的变化进行了观察和比较.观察结果表明:正常条件(0g·L-1NaCl)下,5个树种叶肉细胞在叶绿体形态、嗜锇颗粒数量等方面略有差异,但均未发生质壁分离现象.经NaCl胁迫处理后,5个树种叶肉细胞中的叶绿体和细胞核受到不同程度的损伤,表现为叶绿体膜消失,类囊体片层结构肿胀,叶绿体降解,嗜锇颗粒增大或增多,细胞核的核膜消失、核染色质凝聚;且随NaCl质量浓度的提高,损伤程度均逐渐加剧.4和8g·L-1NaC1胁迫条件下,美国皂荚、茶条槭和水紫树的叶肉细胞发生质壁分离现象,而红桤木、美国白蜡和水紫树的叶肉细胞内出现环状片层.根据观察结果,推测红桤木和美国白蜡对NaCl胁迫的耐性较强,美国皂荚和茶条槭也有一定的耐性,而水紫树的耐性最弱.%In order to definite the salt tolerance of five tree species introduced from North America, such as Fraxinus americana L., Acer ginnala Maxim., Alnus rubra Bong., Nyssa aquatica L. And Gleditsia triacanthos L., using water culture method, the ultrastructure of mesophyll cells of one-year-old seedlings of them after treated with 0( CK) , 4 and 8 g ? L-1 NaCl was observed and compared by TEM technique. The observation results show that under normal condition (0 g ? L-1 NaCl) , mesophyll cell of five tree species has slight difference in chloroplast morphology and osmiophilic granule number, and so on, but no occurrence of plasmolysis. Generally, chloroplasts and cell nuclei of mesophyll cells of five tree species are injured at different degrees after stressed by NaCl, it is presented as

  12. Mesophyll conductance and reaction-diffusion models for CO

    NARCIS (Netherlands)

    Berghuijs, Herman N.C.; Yin, Xinyou; Tri Ho, Q.; Driever, Steven M.; Retta, Moges A.; Nicolaï, Bart M.; Struik, Paul C.

    2016-01-01

    One way to increase potential crop yield could be increasing mesophyll conductance gm. This variable determines the difference between the CO2 partial pressure in the intercellular air spaces (Ci) and that near Rubisco (Cc). Various methods can determin

  13. The photosynthetic capacity in 35 ferns and fern allies: mesophyll CO2 diffusion as a key trait.

    Science.gov (United States)

    Tosens, Tiina; Nishida, Keisuke; Gago, Jorge; Coopman, Rafael Eduardo; Cabrera, Hernán Marino; Carriquí, Marc; Laanisto, Lauri; Morales, Loreto; Nadal, Miquel; Rojas, Roke; Talts, Eero; Tomas, Magdalena; Hanba, Yuko; Niinemets, Ülo; Flexas, Jaume

    2016-03-01

    Ferns and fern allies have low photosynthetic rates compared with seed plants. Their photosynthesis is thought to be limited principally by physical CO2 diffusion from the atmosphere to chloroplasts. The aim of this study was to understand the reasons for low photosynthesis in species of ferns and fern allies (Lycopodiopsida and Polypodiopsida). We performed a comprehensive assessment of the foliar gas-exchange and mesophyll structural traits involved in photosynthetic function for 35 species of ferns and fern allies. Additionally, the leaf economics spectrum (the interrelationships between photosynthetic capacity and leaf/frond traits such as leaf dry mass per unit area or nitrogen content) was tested. Low mesophyll conductance to CO2 was the main cause for low photosynthesis in ferns and fern allies, which, in turn, was associated with thick cell walls and reduced chloroplast distribution towards intercellular mesophyll air spaces. Generally, the leaf economics spectrum in ferns follows a trend similar to that in seed plants. Nevertheless, ferns and allies had less nitrogen per unit DW than seed plants (i.e. the same slope but a different intercept) and lower photosynthesis rates per leaf mass area and per unit of nitrogen.

  14. Efeitos de hexazinone e diuron, e suas misturas, no controle de capim-de-colchão (Digitaria sanguinalis (L. Scop em cana-de-açúcar (Saccharum spp Effects of hexazinone and diuron and mixtures on crabgrass (Digitaria sanguinalis (L. Scop control on sugarcane (Saccharum spp

    Directory of Open Access Journals (Sweden)

    L. S. P. Cruz

    1983-06-01

    Full Text Available Foi conduzido em 1976 /77, um experimento de campo em área do Centro de Tecnologia da Copersucar, em Piracicaba, SP , com a finalidade de se conhecer o efeito dos herbicidas hexazinone e diuron , assim como o de suas misturas, no controle do capim-de -colchão (Digitaria sanguinalis (L. Scop em avançado estádio de desenvolvimento vegetativo infestando cultura de cana-deaçúcar (Saccharum spp. Os tratamentos constaram da aplicação pós - emergente de hexazinone a 0,30, 0,35, 0,45 e 0, 65 kg/h a; de diuro na 0, 88 , 1, 20 e 2, 50 kg/h a; de hexazinone -i - diuron a 0,30 0,88, 0,35 + 1 , 2 0 e 0 , 4 5 + 1 , 3 6 kg / ha . Foram incluídos mais dois tratamentos com herbicidas ( ter - bacila 0,9 6 kg/ ha e metribuzin a 1,5 0 kg/ ha e um sem herbicida, mantidos empreno limpo com o auxílio de enxada. Esses 13 tratamentos foram distribuídos em blocos ao acaso, com quatro repetições. Foram determinados também os efeitos dos tratamentos sobre a produção de cana -de-açúcar no campo e sobre suas características tecnológicas (Brix, Pol, Pureza, Fibra. Os melhores resultados de controle da gramínea , aos 15 dias da aplicação dos herbicidas , foram obtidos com a mistura de hexazinone a 0, 45 kg/h a com diuron a 1, 36 kg/h a. Hexazinon e a 0,6 4 kg /h a, aplicado isolado, também apresentou bons resultados de controle. Nos tratamentos com hexazinone apareceram sintomas de fitotoxicidade na cana-de-açúcar, os quais desapareceram posteriormente, sem interferir na produção. Os demais tratamentos também não foram prejudiciais à cana de-açúcar.A field experiment was carried out at the Centre of Technology of Copers ucar, Piracicaba , SP, to know the action of hexazinone and diuron and mixtures on crab grass (Digitaria sanguinali s (L . Scop control, at advanced stage of development in sugarcane crop. Treatments were post -emergence aplication of hexazinone at 0,30; 0,35; 0,45 and 0,64 kg/ha; diuron at 0,88; 1,20 ; 1,36 and 2, 50 kg/h a

  15. Comparative studies on leaf epidermal micromorphology and mesophyll structure of Elaeagnus angustifolia L. in two different regions of desert habitat

    Institute of Scientific and Technical Information of China (English)

    MengMeng Li; YuBing Liu; MeiLing Liu; Dan Liu

    2015-01-01

    In order to obtain qualitative and quantitative characteristics of leaf epidermal micromorphology and mesophyll structure to evaluate the responses of Elaeagnus angustifolia L. to different environmental factors, epidermal micromorphology was observed by scanning electron microscopy (SEM), and mesophyll structure was studied by light microscopy (LM) and transmission electron microscopy (TEM). Materials were selected from Linze County, Gansu Province (material A) and Qitai County, Xinjiang Uygur Autonomous Region (material B) of China. Results show that lamina thickness was higher in material A, with one layer of epidermal cells in both adaxial and abaxial surfaces, and epidermal cell radial length was significantly longer in the adaxial surface. E. angustifolia leaves are typically bifacial, with a higher ratio of palisade to spongy tissue in material A. The thickness of trichome layer of epidermis was thicker in material A. In contrast, cell wall and cuticular wax of the epidermal cells were thinner in material A than in material B. Chloroplast ultrastructure was different with the approximate spherical chloroplast containing numerous starch grains and osmiophilic granules in ma-terial A, while only the spindly chloroplast contained starch grains in material B. Multiple layers of peltate or stel-late-peltate trichomes occupied both leaf surfaces in material A and the abaxial surface in material B, while the adaxial surface of material B contained few trichomes. Stomata were not observed on the leaf surfaces in materials A and B by SEM because of trichome obstruction. Our results indicate that the leaf structure of E. angustifolia is closely correlated with environmental factors, and the combination of leaf epidermal micromorphology and mesophyll structure afford re-sistance to environmental stress.

  16. Cytological investigations of mesophyll of Phaseolus vulgaris L. 'Red Kidney' infected with PVS

    Directory of Open Access Journals (Sweden)

    Krystyna Brzezicka-Szymczyk

    2013-12-01

    Full Text Available We have put under cytological observation 2-, 4-, and 8-day fragments of mesophyll of the leaves Phaseolus 'Red Kidney' infected with PVS. In the necrosis caused by PVS can be distinguished a necrotic centre, a seminecrotic zone, and a belt of terminal cells. The necrotic centre is the most changed area whose cells are most often decayed. In the seminecrotic zone, the presence of viruses in the cell causes some pathological changes. The ER canals assume the shape of swollen cisterns. The chloroplasts reacts with the softening of granas, the growth of starch granules and plastoglobules content as well as with the presence of proteinaceous fibrous structures. The karyolymph and mitochondrium matrix become elucidated. The continuity of plasmalemma and tonoplast become interrupted. Virus particles appear in the area of cytoplasm of seminecrotic zone and in the necrotic centre, they are dispersed or rarely arranged in aggregations which often are in contact with tonoplast. We have observed virus packs enclosed with lipoproteid membrane. Viruses were not stated in the terminal zone. We have ascertained the intensive development of cell walls in the cells of terminal and seminecrotic zones. A lobar or punctual way of the development appeared in different areas of the cell wall and was found independently in various cells. The modified areas included as well plasmodesmata. The above observations enable us to presume that the cells of necrotic centre and seminecrotic zone are the place of replication and assembling of viruses and is responsible for the mechanical localization of virus infection.

  17. The paraveinal mesophyll of soybean leaves in relation to assimilate transfer and compartmentation : II. Structural, metabolic and compartmental changes during reproductive growth.

    Science.gov (United States)

    Franceschi, V R; Giaquinta, R T

    1983-04-01

    Nitrogen and carbohydrate assimilates were temporally and spatially compartmented among various cell types in soybean (Glycine max L., Merr.) leaves during seed filling. The paraveinal mesophyll (PVM), a unique cell layer found in soybean, was demonstrated to function in the synthesis, compartmentation and remobilization of nitrogen reserves prior to and during the seed-filling stages. At anthesis, the PVM vacuoles contain substantial protein which completely disappears by two weeks into the seed filling. Distinct changes in the PVM cytoplasm, tonoplast and organelles were correlated with the presence or absence of the vacuolar material. Microautoradiography following the accumulation of several radiolabeled sugars and amino acids demonstrated the glycoprotein nature of the vacuolar material. Incorporation of methionine, leucine, glucose, and glucosamine resulted in heavy labelling of the PVM vacuole, in contrast to galactose, proline, and mannose which resulted in a much reduced labelling pattern. In addition, starch is unequally compartmented and degraded among the various leaf cells during seed filling. At the end of the photoperiod at the flowering stage, the highest starch accumulation was in the second palisade layer followed by the spongy mesophyll and the first (uppermost) palisade layer. Starch in the first palisade layer was completely degraded during the dark whereas the starch in the second palisade and spongy mesophyll was not remobilized to any appreciable extent. By mid-podfilling (approximately five weeks postanthesis) starch was absent in the first palisade layer at the end of the photoperiod while the second palisade and spongy mesophyll layers contained substantial starch. Starch was remobilized from these latter cells during the remainder of seed filling when current photosynthetic production is low. Structural changes associated with cell senescence first appear in the upper palisade layer and then progress (excluding the PVM) to the second

  18. Differential positioning of C4 mesophyll and bundle sheath chloroplasts: aggregative movement of C4 mesophyll chloroplasts in response to environmental stresses.

    Science.gov (United States)

    Yamada, Masahiro; Kawasaki, Michio; Sugiyama, Tatsuo; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2009-10-01

    In C(4) plants, mesophyll (M) chloroplasts are randomly distributed along the cell walls, while bundle sheath (BS) chloroplasts are typically located in either a centripetal or centrifugal position. We investigated whether these intracellular positions are affected by environmental stresses. When mature leaves of finger millet (Eleusine coracana) were exposed to extremely high intensity light, most M chloroplasts aggregatively re-distributed to the BS side, whereas the intracellular arrangement of BS chloroplasts was unaffected. Compared with the homologous light-avoidance movement of M chloroplasts in C(3) plants, it requires extremely high light (3,000-4,000 micromol m(-2) s(-1)) and responds more slowly (distinctive movement observed in 1 h). The high light-induced movement of M chloroplasts was also observed in maize (Zea mays), another C(4) species, but with a distinct pattern of redistribution along the sides of anticlinal walls, analogous to C(3) plants. The aggregative movement of M chloroplasts occurred at normal light intensities (250-500 micromol m(-2) s(-1)) in response to environmental stresses, such as drought, salinity and hyperosmosis. Moreover, the re-arrangement of M chloroplasts was observed in field-grown C(4) plants when exposed to mid-day sunlight, but also under midsummer drought conditions. The migration of M chloroplasts was controlled by actin filaments and also induced in a light-dependent fashion upon incubation with ABA, which may be the physiological signal transducer. Together these results suggest that M and BS cells of C(4) plants have different mechanisms controlling intracellular chloroplast positioning, and that the aggregative movement of C(4) M chloroplasts is thought to be a protective response under environmental stress conditions.

  19. Epidermal Micromorphology and Mesophyll Structure of Populus euphratica Heteromorphic Leaves at Different Development Stages.

    Science.gov (United States)

    Liu, Yubing; Li, Xinrong; Chen, Guoxiong; Li, Mengmeng; Liu, Meiling; Liu, Dan

    2015-01-01

    Leaf epidermal micromorphology and mesophyll structure during the development of Populus euphratica heteromorphic leaves, including linear, lanceolate, ovate, dentate ovate, dentate rhombic, dentate broad-ovate and dentate fan-shaped leaves, were studied by using electron and light microscopy. During development of heteromorphic leaves, epidermal appendages (wax crystals and trichomes) and special cells (mucilage cells and crystal idioblasts) increased in all leaf types while chloroplast ultrastructure and stomatal characters show maximum photosynthetic activity in dentate ovate and rhombic leaves. Also, functional analysis by subordinate function values shows that the maximum adaptability to adverse stress was exhibited in the broad type of mature leaves. The 12 heteromorphic leaf types are classified into three major groups by hierarchical cluster analysis: young, developing and mature leaves. Mature leaves can effectively obtain the highest stress resistance by combining the protection of xerophytic anatomy from drought stress, regulation of water uptake in micro-environment by mucilage and crystal idioblasts, and assistant defense of transpiration reduction through leaf epidermal appendages, which improves photosynthetic activity under arid desert conditions. Our data confirms that the main leaf function is differentiated during the developing process of heteromorphic leaves.

  20. Culture and fusion of pollen protoplasts of Brassica oleracea L. var. italica with haploid mesophyll protoplasts of B. rapa L. ssp. pekinensis.

    Science.gov (United States)

    Liu, Fan; Ryschka, U; Marthe, F; Klocke, E; Schumann, G; Zhao, H

    2007-01-01

    Hybrid callus was formed from the successful protoplast fusion between pollen protoplasts of Brassica oleracea var. italica and haploid mesophyll protoplasts of Brassica rapa. The pollen protoplast isolation frequency in broccoli was highly related to the ratio of trinucleate pollens in the male gametophyte population. Large quantities of pollen protoplasts with high vigor could be isolated, and the isolation frequency reached up to 90% in 6.0-7.0 mm long flower buds with about 94.7% trinucleate-stage pollens. Pollen protoplasts could be collected and purified by discontinuous gradient centrifugation. In 1% Na-alginate embedding culture, cell divisions were observed but no further development was found. The haploid mesophyll protoplasts were isolated from in vitro haploid plants of B. rapa. Results strongly showed the variability in culturability of mesophyll protoplasts from different haploid lines. Both pollen protoplasts and haploid mesophyll protoplasts retained a stable round shape in the designed prefusion solution with an osmotic pressure of 0.74 osmol/kg. Polyethylene glycol was used for the protoplast fusion, and 40% polyethylene glycol 4000 enabled the highest fusion frequency of about 20%. Some postfusion protoplasts showed cell divisions up to callus proliferation. Calli were screened by random amplified polymorphic DNA analysis for their hybrid character. Results revealed the existence of the hybrid calli. Some of the hybrid calli grew well with green color and shoot primordia. According to our knowledge, this is the first report about a hybrid formation between two haploid protoplasts. Potential comprehensive applications, as well as problems of this technique, are discussed.

  1. Mesophyll Chloroplast Investment in C3, C4 and C2 Species of the Genus Flaveria.

    Science.gov (United States)

    Stata, Matt; Sage, Tammy L; Hoffmann, Natalie; Covshoff, Sarah; Ka-Shu Wong, Gane; Sage, Rowan F

    2016-05-01

    The mesophyll (M) cells of C4 plants contain fewer chloroplasts than observed in related C3 plants; however, it is uncertain where along the evolutionary transition from C3 to C4 that the reduction in M chloroplast number occurs. Using 18 species in the genus Flaveria, which contains C3, C4 and a range of C3-C4 intermediate species, we examined changes in chloroplast number and size per M cell, and positioning of chloroplasts relative to the M cell periphery. Chloroplast number and coverage of the M cell periphery declined in proportion to increasing strength of C4 metabolism in Flaveria, while chloroplast size increased with increasing C4 cycle strength. These changes increase cytosolic exposure to the cell periphery which could enhance diffusion of inorganic carbon to phosphenolpyruvate carboxylase (PEPC), a cytosolic enzyme. Analysis of the transcriptome from juvenile leaves of nine Flaveria species showed that the transcript abundance of four genes involved in plastid biogenesis-FtsZ1, FtsZ2, DRP5B and PARC6-was negatively correlated with variation in C4 cycle strength and positively correlated with M chloroplast number per planar cell area. Chloroplast size was negatively correlated with abundance of FtsZ1, FtsZ2 and PARC6 transcripts. These results indicate that natural selection targeted the proteins of the contractile ring assembly to effect the reduction in chloroplast numbers in the M cells of C4 Flaveria species. If so, efforts to engineer the C4 pathway into C3 plants might evaluate whether inducing transcriptome changes similar to those observed in Flaveria could reduce M chloroplast numbers, and thus introduce a trait that appears essential for efficient C4 function.

  2. Arabidopsis ANGULATA10 is required for thylakoid biogenesis and mesophyll development.

    Science.gov (United States)

    Casanova-Sáez, Rubén; Mateo-Bonmatí, Eduardo; Kangasjärvi, Saijaliisa; Candela, Héctor; Micol, José Luis

    2014-06-01

    The chloroplasts of land plants contain internal membrane systems, the thylakoids, which are arranged in stacks called grana. Because grana have not been found in Cyanobacteria, the evolutionary origin of genes controlling the structural and functional diversification of thylakoidal membranes in land plants remains unclear. The angulata10-1 (anu10-1) mutant, which exhibits pale-green rosettes, reduced growth, and deficient leaf lateral expansion, resulting in the presence of prominent marginal teeth, was isolated. Palisade cells in anu10-1 are larger and less packed than in the wild type, giving rise to large intercellular spaces. The ANU10 gene encodes a protein of unknown function that localizes to both chloroplasts and amyloplasts. In chloroplasts, ANU10 associates with thylakoidal membranes. Mutant anu10-1 chloroplasts accumulate H2O2, and have reduced levels of chlorophyll and carotenoids. Moreover, these chloroplasts are small and abnormally shaped, thylakoidal membranes are less abundant, and their grana are absent due to impaired thylakoid stacking in the anu10-1 mutant. Because the trimeric light-harvesting complex II (LHCII) has been reported to be required for thylakoid stacking, its levels were determined in anu10-1 thylakoids and they were found to be reduced. Together, the data point to a requirement for ANU10 for chloroplast and mesophyll development.

  3. Routes to the tonoplast: the sorting of tonoplast transporters in Arabidopsis mesophyll protoplasts.

    Science.gov (United States)

    Wolfenstetter, Susanne; Wirsching, Petra; Dotzauer, Dorina; Schneider, Sabine; Sauer, Norbert

    2012-01-01

    Vacuoles perform a multitude of functions in plant cells, including the storage of amino acids and sugars. Tonoplast-localized transporters catalyze the import and release of these molecules. The mechanisms determining the targeting of these transporters to the tonoplast are largely unknown. Using the paralogous Arabidopsis thaliana inositol transporters INT1 (tonoplast) and INT4 (plasma membrane), we performed domain swapping and mutational analyses and identified a C-terminal di-leucine motif responsible for the sorting of higher plant INT1-type transporters to the tonoplast in Arabidopsis mesophyll protoplasts. We demonstrate that this motif can reroute other proteins, such as INT4, SUCROSE TRANSPORTER2 (SUC2), or SWEET1, to the tonoplast and that the position of the motif relative to the transmembrane helix is critical. Rerouted INT4 is functionally active in the tonoplast and complements the growth phenotype of an int1 mutant. In Arabidopsis plants defective in the β-subunit of the AP-3 adaptor complex, INT1 is correctly localized to the tonoplast, while sorting of the vacuolar sucrose transporter SUC4 is blocked in cis-Golgi stacks. Moreover, we demonstrate that both INT1 and SUC4 trafficking to the tonoplast is sensitive to brefeldin A. Our data show that plants possess at least two different Golgi-dependent targeting mechanisms for newly synthesized transporters to the tonoplast.

  4. Abscisic acid and blue light signaling pathways in chloroplast movements in Arabidopsis mesophyll.

    Science.gov (United States)

    Eckstein, Aleksandra; Krzeszowiec, Weronika; Banaś, Agnieszka Katarzyna; Janowiak, Franciszek; Gabryś, Halina

    2016-01-01

    Abscisic acid (ABA) and phototropins act antagonistically to control stomatal movements. Here, we investigated the role of ABA in phototropin-directed chloroplast movements in mesophyll cells of Arabidopsis thaliana. We analyzed the expression of phototropins at mRNA and protein level under the influence of ABA. PHOT1 mRNA level was decreased by ABA in the dark while it was insensitive to ABA in light. PHOT2 mRNA level was independent of the hormone treatment. The levels of phototropin proteins were down-regulated by ABA, both in darkness and light. No impact of exogenous ABA on amplitudes and kinetics of chloroplast movements was detected. Chloroplast responses in wild type Arabidopsis and three mutants, abi4, abi2 (abscisic acid insensitive4, 2) and aba1 (abscisic acid1), were measured to account for endogenous ABA signaling. The chloroplast responses were slightly reduced in abi2 and aba1 mutants in strong light. To further investigate the effect, abi2 and aba1 mutants were supplemented with exogenous ABA. In the aba1 mutant, the reaction was rescued but in abi2 it was unaffected. Our results show that ABA is not directly involved in phototropin-controlled chloroplast responses in mature leaves of Arabidopsis. However, the disturbance of ABA biosynthesis and signaling in mutants affects some elements of the chloroplast movement mechanism. In line with its role as a stress hormone, ABA appears to enhance plant sensitivity to light and promote the chloroplast avoidance response.

  5. In vitro shoot regeneration from leaf mesophyll protoplasts of hybrid poplar (Populus nigra x P. maximowiczii).

    Science.gov (United States)

    Park, Y G; Son, S H

    1992-02-01

    Protoplasts were isolated from leaf mesophyll of hybrid poplar (Populus nigra X P. maximowiczii) with a mean yield of 10.4 x 10(6) protoplasts per g fresh weight using 2.0% Cellulase 'Onozuka' R-10, 0.8% Macerozyme R-10, 1.2% Hemicellulase, 2.0% Driselase, and 0.05% Pectolyase Y-23 with CPW salts solution containing 0.6 M mannitol, 0.002 M DTT, 3 mM MES at pH 5.6. A liquid plating method produced the highest frequency of dividing protoplasts (48.6%) using an MS medium without NH4NO3. The highest percent of colony formation was 22.8%, produced with fabric supported semi-solid (0.5% w/v) agar plating method using the same culture medium. Growing cell colonies and/or micro-calli were transferred to a fresh semisolid agar medium containing 0.44 μM BAP and 9.0 μM 2,4-D. Multiple shoots were produced from protoplast-derived callus after culture on MS medium containing 6.8 μM zeatin. After root induction on half-strength MS medium that lacked growth regulators, shoots were transferred to pots containing artificial soil mix.

  6. Photosystem II efficiency of the palisade and spongy mesophyll in Quercus coccifera using adaxial/abaxial illumination and excitation light sources with wavelengths varying in penetration into the leaf tissue.

    Science.gov (United States)

    Peguero-Pina, José Javier; Gil-Pelegrín, Eustaquio; Morales, Fermín

    2009-01-01

    The existence of major vertical gradients within the leaf is often overlooked in studies of photosynthesis. These gradients, which involve light heterogeneity, cell composition, and CO(2) concentration across the mesophyll, can generate differences in the maximum potential PSII efficiency (F (V)/F (M) or F (V)/F (P)) of the different cell layers. Evidence is presented for a step gradient of F (V)/F (P) ratios across the mesophyll, from the adaxial (palisade parenchyma, optimal efficiencies) to the abaxial (spongy parenchyma, sub-optimal efficiencies) side of Quercus coccifera leaves. For this purpose, light sources with different wavelengths that penetrate more or less deep within the leaf were employed, and measurements from the adaxial and abaxial sides were performed. To our knowledge, this is the first report where a low photosynthetic performance in the abaxial side of leaves is accompanied by impaired F (V)/F (P) ratios. This low photosynthetic efficiency of the abaxial side could be related to the occurrence of bundle sheath extensions, which facilitates the penetration of high light intensities deep within the mesophyll. Also, leaf morphology (twisted in shape) and orientation (with a marked angle from the horizontal plane) imply direct sunlight illumination of the abaxial side. The existence of cell layers within leaves with different photosynthetic efficiencies makes appropriate the evaluation of how light penetrates within the mesophyll when using Chl fluorescence or gas exchange techniques that use different wavelengths for excitation and/or for driving photosynthesis.

  7. 盐胁迫对酿酒葡萄叶片细胞结构及光合特性的影响%Effects of Salt Stress on Mesophyll Cell Structures and Photosynthetic Characteristics in Leaves of Wine Grape (Vitis spp.)

    Institute of Scientific and Technical Information of China (English)

    秦玲; 康文怀; 齐艳玲; 蔡爱军

    2012-01-01

    100 mmol·L-1 for 30 d. When the height of grapevines was about 60 cm, chlorophyll contents, gas exchange and chlorophyll fluorescence parameters, and cell structure characteristics in leaves were determined by using spectrophotometer, chlorophyll fluorometer, and observed with microscope and transmission electron microscopy. [Results] Compared with the control, the thickness of epidermis cells, palisade tissue and spongy tissue in leaves of grapevine increased, and thickness ratio of the palisade/spongy tissue reduced under salt stress(100 mmol·L-1 NaCl). Thylakoids became swollen, the length and width of chloroplast increased by 130%-150% and 130%-200%, respectively. Meanwhile, chlorophyll (especially Ch1 b) content, PSⅡ potential activity(Fv/Fo), maximal photochemistry efficiency of PSII (Fv/Fm) and net photosynthetic rate(Pn) dramatically decreased in leaves of grapevines under salt stress(100 mmol·L-1 NaCl). There was a difference in effect on three grapevines by salt stress. Among them, '5BB' showed a lesser negative effect on cell and chloroplast structures, photosynthetic rate, and PSⅡ photochemical reaction. 'Cabernet Sauvignon' in the middle and 'Cabernet Sauvignon/5BB' was the largest. [Conclusion] The alterations of mesophyll cell structure and chlorophyll content under salt stress(100 mmol-L"1 NaCl) could led to the deduction of photosynthetic electron transfer efficiency and photosynthetic rate. Rootstock '5BB' exhibited higher salt-tolerance characters which may be beneficial to improve the salt-tolerance of 'Cabernet Sauvignon' by grafting on the '5BB'.

  8. Mesophyll conductance and leaf carbon isotope composition of two high elevation conifers along an altitudinal gradient

    Science.gov (United States)

    Guo, J.; Beverly, D.; Cook, C.; Ewers, B.; Williams, D. G.

    2016-12-01

    Carbon isotope ratio values (δ13C) of conifer leaf material generally increases with elevation, potentially reflecting decreases in the leaf internal to ambient CO2 concentration ratio (Ci/Ca) during photosynthesis. Reduced stomatal conductance or increased carboxylation capacity with increasing elevation could account for these patterns. But some studies reported conifers δ13C increased with altitude consistently, but Ci/Ca did not significantly decrease and leaf nitrogen content remained constant with increasing of altitude in Central Rockies. Variation in leaf mesophyll conductance to CO2 diffusion, which influences leaf δ13C independently of effects related to stomatal conductance and carboxylation demand, might reconcile these conflicting observations. Leaf mass per unit area (LMA) increases with altitude and often correlates with δ13C and mesophyll conductance. Therefore, we hypothesized that increases in δ13C of conifers with altitude are controlled mainly by changes in mesophyll conductance. To test this hypothesis, leaf δ13C, photosynthetic capacity, leaf nitrogen content, LMA, and mesophyll conductance were determined on leaves of two dominant conifers (Pinus contorta and Picea engelmannii) along a 90-km transect in SE Wyoming at altitudes ranging from 2400 to 3200 m above sea level. Mesophyll conductance was determined by on-line 13C discrimination using isotope laser spectroscopy. We expected to observe relatively small differences in stomatal conductance and decreases in mesophyll conductance from lower and higher altitude sites. Such a pattern would have important implications for how differences in leaf δ13C values across altitude are interpreted in relation to forest water use and productivity from scaling of leaf-level water-use efficiency.

  9. Impact of Mesophyll Diffusion on Estimated Global Land CO2 Fertilization

    Science.gov (United States)

    Sun, Y.; Gu, L.; Dickinson, R. E.

    2014-12-01

    In C3 plants, CO2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdown and so overestimate CO2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO2 fertilization effect (CFE) for global gross primary production (GPP) from 915 PgC to 1057 PgC for the period of 1901 to 2010. This increase represents a 16% correction large enough to explain the persistent overestimation of growth rates of historical atmospheric CO2 by Earth System Models. Without this correction, the CFE for global GPP is underestimated by 0.05 PgC yr-1ppm-1. This finding implies that the contemporary terrestrial biosphere is more CO2-limited than previously thought.

  10. Impact of mesophyll diffusion on estimated global land CO2 fertilization.

    Science.gov (United States)

    Sun, Ying; Gu, Lianhong; Dickinson, Robert E; Norby, Richard J; Pallardy, Stephen G; Hoffman, Forrest M

    2014-11-01

    In C3 plants, CO2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdown and therefore overestimate CO2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO2 fertilization effect (CFE) for global gross primary production (GPP) from 915 to 1,057 PgC for the period of 1901-2010. This increase represents a 16% correction, which is large enough to explain the persistent overestimation of growth rates of historical atmospheric CO2 by Earth system models. Without this correction, the CFE for global GPP is underestimated by 0.05 PgC/y/ppm. This finding implies that the contemporary terrestrial biosphere is more CO2 limited than previously thought.

  11. Virtual microstructural leaf tissue generation based on cell growth modeling

    NARCIS (Netherlands)

    Abera, M.K.; Retta, M.A.; Verboven, P.; Nicolai, B.M.; Berghuijs, H.; Struik, P.

    2016-01-01

    A cell growth algorithm for virtual leaf tissue generation is presented based on the biomechanics of plant cells in tissues. The algorithm can account for typical differences in epidermal layers, palisade mesophyll layer and spongy mesophyll layer which have characteristic differences in the shap

  12. Large-scale protein-protein interaction analysis in Arabidopsis mesophyll protoplasts by split firefly luciferase complementation.

    Directory of Open Access Journals (Sweden)

    Jian-Feng Li

    Full Text Available Protein-protein interactions (PPIs constitute the regulatory network that coordinates diverse cellular functions. There are growing needs in plant research for creating protein interaction maps behind complex cellular processes and at a systems biology level. However, only a few approaches have been successfully used for large-scale surveys of PPIs in plants, each having advantages and disadvantages. Here we present split firefly luciferase complementation (SFLC as a highly sensitive and noninvasive technique for in planta PPI investigation. In this assay, the separate halves of a firefly luciferase can come into close proximity and transiently restore its catalytic activity only when their fusion partners, namely the two proteins of interest, interact with each other. This assay was conferred with quantitativeness and high throughput potential when the Arabidopsis mesophyll protoplast system and a microplate luminometer were employed for protein expression and luciferase measurement, respectively. Using the SFLC assay, we could monitor the dynamics of rapamycin-induced and ascomycin-disrupted interaction between Arabidopsis FRB and human FKBP proteins in a near real-time manner. As a proof of concept for large-scale PPI survey, we further applied the SFLC assay to testing 132 binary PPIs among 8 auxin response factors (ARFs and 12 Aux/IAA proteins from Arabidopsis. Our results demonstrated that the SFLC assay is ideal for in vivo quantitative PPI analysis in plant cells and is particularly powerful for large-scale binary PPI screens.

  13. The avoidance and aggregative movements of mesophyll chloroplasts in C(4) monocots in response to blue light and abscisic acid.

    Science.gov (United States)

    Maai, Eri; Shimada, Shouu; Yamada, Masahiro; Sugiyama, Tatsuo; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2011-05-01

    In C(4) plants, mesophyll (M) chloroplasts are randomly distributed along the cell walls, whereas bundle sheath chloroplasts are located in either a centripetal or centrifugal position. It was reported previously that only M chloroplasts aggregatively redistribute to the bundle sheath side in response to extremely strong light or environmental stresses. The aggregative movement of M chloroplasts is also induced in a light-dependent fashion upon incubation with abscisic acid (ABA). The involvement of reactive oxygen species (ROS) and red/blue light in the aggregative movement of M chloroplasts are examined here in two distinct subtypes of C(4) plants, finger millet and maize. Exogenously applied hydrogen peroxide or ROS scavengers could not change the response patterns of M chloroplast movement to light and ABA. Blue light irradiation essentially induced the rearrangement of M chloroplasts along the sides of anticlinal walls, parallel to the direction of the incident light, which is analogous to the avoidance movement of C(3) chloroplasts. In the presence of ABA, most of the M chloroplasts showed the aggregative movement in response to blue light but not red light. Together these results suggest that ROS are not involved in signal transduction for the aggregative movement, and ABA can shift the blue light-induced avoidance movement of C(4)-M chloroplasts to the aggregative movement.

  14. Roles of mesophyll conductance and plant functional diversities in tropical photosynthesis

    Science.gov (United States)

    Gu, L.

    2013-12-01

    Tropical photosynthesis dominates global terrestrial gross primary production (GPP) and will likely play a defining role in determining how global GPP will respond to climate change. Yet, our current understanding of biological, ecological, edaphic and environmental controls on tropical photosynthesis is poor. The overly simplistic schemes that current Earth System Models use to simulate tropical photosynthesis cannot capture the functional diversities associated with high species diversities in the tropics. New approaches that explicitly represent the functional diversities of tropical photosynthesis in Earth System Models are needed in order to realistically model responses of tropical photosynthesis to increased atmospheric CO2 concentrations and associated climate changes. To establish a basis for such approaches, we conducted intensive field measurements of leaf photosynthesis at three forest sites along a strong rainfall gradient in Panama in 2012-2013. The three sites are Parque Natural Metropolitano, Gamboa, and Parque Nacional San Lorenzo. The Parque Natural Metropolitano receives an annual precipitation of less than 1800mm and Parque Nacional San Lorenzo over 3300 mm with Gamboa in between. The three sites differ in species diversity with Parque Nacional San Lorenzo having the highest species diversity and Parque Nacional San Lorenzo the lowest. At the three contrasting sites, we measured A/Ci curves, leaf traits and leaf nutrient (N and P) contents of about 100 species. We determined mesophyll conductance with the LeafWeb approach. From these measurements, we developed practical but realistic parameterizations of functional diversities of tropical plant species at the three sites and implemented these parameterizations in the latest version of the Community Land Model. We found that mesophyll conductance is key to representing functional diversities of tropical forest species. Without it, responses of tropical photosynthesis to increased atmospheric CO2

  15. Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

    Directory of Open Access Journals (Sweden)

    Giuseppe Sorrentino

    Full Text Available The rate of photosynthesis (A of plants exposed to water deficit is a function of stomatal (gs and mesophyll (gm conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci. Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis.

  16. Variation among Soybean Cultivars in Mesophyll Conductance and Leaf Water Use Efficiency

    Directory of Open Access Journals (Sweden)

    James Bunce

    2016-12-01

    Full Text Available Improving water use efficiency (WUE may prove a useful way to adapt crop species to drought. Since the recognition of the importance of mesophyll conductance to CO2 movement from inside stomatal pores to the sites of photosynthetic carboxylation, there has been interest in how much intraspecific variation in mesophyll conductance (gm exists, and how such variation may impact leaf WUE within C3 species. In this study, the gm and leaf WUE of fifteen cultivars of soybeans grown under controlled conditions were measured under standardized environmental conditions. Leaf WUE varied by a factor of 2.6 among the cultivars, and gm varied by a factor of 8.6. However, there was no significant correlation (r = −0.047 between gm and leaf WUE. Leaf WUE was linearly related to the sub-stomatal CO2 concentration. The value of gm affected the ratio of maximum Rubisco carboxylation capacity calculated from the sub-stomatal CO2 concentration to that calculated from the CO2 concentration at the site of carboxylation. That is, variation in gm affected the efficiency of Rubisco carboxylation, but not leaf WUE. Nevertheless, there is considerable scope for genetically improving soybean leaf water use efficiency.

  17. Kþ retention in leaf mesophyll, an overlooked component of salinity tolerance mechanism:A case study for barley

    Institute of Scientific and Technical Information of China (English)

    Sergey Shabala

    2015-01-01

    Plant salinity tolerance is a physiological y complex trait, with numerous mechanisms contributing to it. In this work, we show that the ability of leaf mesophyl to retain Kþ represents an important and essential y overlooked component of a salinity tolerance mechanism. The strong positive correlation between mesophyl Kþ retention ability under saline conditions (quantified by the magnitude of NaCl‐induced Kþ efflux from mesophyl ) and the overal salinity tolerance (relative fresh weight and/or survival or damage under salinity stress) was found while screening 46 barley (Hordeum vulgare L.) genotypes contrasting in their salinity tolerance. Genotypes with intrinsical y higher leaf Kþ content under control conditions were found to possess better Kþ retention ability under salinity and, hence, overal higher tolerance. Contrary to previous reports for barley roots, Kþ retention in mesophyl was not associated with an increased Hþ‐pumping in tolerant varieties but instead correlated negatively with this trait. These findings are explained by the fact that increased Hþ extrusion may be needed to charge balance the activity and provide the driving force for the high affinity HAK/KUP Kþ transporters required to restore cytosolic Kþ homeostasis in salt‐sensitive genotypes.

  18. Simple generalisation of a mesophyll resistance model for various intracellular arrangements of chloroplasts and mitochondria in C

    NARCIS (Netherlands)

    Yin, Xinyou; Struik, Paul C.

    2017-01-01

    The classical definition of mesophyll conductance (gm) represents an apparent parameter (gm,app) as it places (photo)respired CO2 at the same compartment where the carboxylation by Rubisco takes place. Recently, Tholen and co-workers developed a framework, in whic

  19. Isolation and identification of thermophilic and mesophylic proteolytic bacteria from shrimp paste "Terasi"

    Science.gov (United States)

    Murwani, R.; Supriyadi, Subagio, Trianto, A.; Ambariyanto

    2015-12-01

    Terasi is a traditional product generally made of fermented shrimp. There were many studies regarding lactic acid bacteria of terasi but none regarding proteolitic bacteria. This study was conducted to isolate and identify the thermophilic and mesophylic proteolytic bacteria from terasi. In addition, the effect of different salt concentrations on the growth of the isolated proteolytic bacteria with the greatest proteolytic activity was also studied. Terasi samples were obtained from the Northern coast region of Java island i.e. Jepara, Demak and Batang. The study obtained 34 proteolytic isolates. Four isolates were identified as Sulfidobacillus, three isolates as Vibrio / Alkaligenes / Aeromonas, two isolates as Pseudomonas, 21 isolates as Bacillus, three isolates as Kurthia/ Caryophanon and one isolates as Amphibacillus. The growth of proteolytic bacteria was affected by salt concentration. The largest growth was found at 0 ppm salt concentrations and growth was declined as salt concentration increased. Maximum growth at each salt concentration tested was found at 8 hours incubation.

  20. Highly efficient isolation of Populus mesophyll protoplasts and its application in transient expression assays.

    Directory of Open Access Journals (Sweden)

    Jianjun Guo

    Full Text Available BACKGROUND: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. METHODOLOGY/PRINCIPAL FINDINGS: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. CONCLUSIONS/SIGNIFICANCE: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  1. Highly Efficient Isolation of Populus Mesophyll Protoplasts and Its Application in Transient Expression Assays

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianjun [ORNL; Morrell-Falvey, Jennifer L [ORNL; Labbe, Jessy L [ORNL; Muchero, Wellington [ORNL; Kalluri, Udaya C [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL

    2012-01-01

    Background: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. Methodology/Principal Findings: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. Conclusions/Significance: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  2. Rapid assessment of gene function in the circadian clock using artificial microRNA in Arabidopsis mesophyll protoplasts.

    Science.gov (United States)

    Kim, Jeongsik; Somers, David E

    2010-10-01

    Rapid assessment of the effect of reduced levels of gene products is often a bottleneck in determining how to proceed with an interesting gene candidate. Additionally, gene families with closely related members can confound determination of the role of even a single one of the group. We describe here an in vivo method to rapidly determine gene function using transient expression of artificial microRNAs (amiRNAs) in Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. We use a luciferase-based reporter of circadian clock activity to optimize and validate this system. Protoplasts transiently cotransfected with promoter-luciferase and gene-specific amiRNA plasmids sustain free-running rhythms of bioluminescence for more than 6 d. Using both amiRNA plasmids available through the Arabidopsis Biological Resource Center, as well as custom design of constructs using the Weigel amiRNA design algorithm, we show that transient knockdown of known clock genes recapitulates the same circadian phenotypes reported in the literature for loss-of-function mutant plants. We additionally show that amiRNA designed to knock down expression of the casein kinase II β-subunit gene family lengthens period, consistent with previous reports of a short period in casein kinase II β-subunit overexpressors. Our results demonstrate that this system can facilitate a much more rapid analysis of gene function by obviating the need to initially establish stably transformed transgenics to assess the phenotype of gene knockdowns. This approach will be useful in a wide range of plant disciplines when an endogenous cell-based phenotype is observable or can be devised, as done here using a luciferase reporter.

  3. Benzophenone Synthase and Chalcone Synthase Accumulate in the Mesophyll of Hypericum perforatum Leaves at Different Developmental Stages.

    Science.gov (United States)

    Belkheir, Asma K; Gaid, Mariam; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2016-01-01

    The active medicinal constituents in Hypericum perforatum, used to treat depression and skin irritation, include flavonoids and xanthones. The carbon skeletons of these compounds are formed by chalcone synthase (CHS) and benzophenone synthase (BPS), respectively. Polyclonal antisera were raised against the polyketide synthases from Hypericum androsaemum and their IgG fractions were isolated. Immunoblotting and immunotitration were used to test the IgGs for crossreactivity and monospecificity in H. perforatum leaf protein extract. Immunofluorescence localization revealed that both CHS and BPS are located in the mesophyll. The maximum fluorescence levels were observed in approx. 0.5 and 1 cm long leaves, respectively. The fluorescence intensity observed for CHS significantly exceeded that for BPS. Using histochemical staining, flavonoids were detected in the mesophyll, indicating that the sites of biosynthesis and accumulation coincide. Our results help understand the biosynthesis and underlying regulation of active H. perforatum constituents.

  4. An Arabidopsis and tomato mesophyll protoplast system for fast identification of early MAMP-triggered immunity-suppressing effectors.

    Science.gov (United States)

    Fraiture, Malou; Zheng, Xiangzi; Brunner, Frédéric

    2014-01-01

    Transient expression in plant mesophyll protoplasts allows rapid characterisation of gene functions in vivo in a simplified and synchronized manner without bias due to the use of bacteria-based gene or protein delivery systems. It offers the possibility to test whether microbial effectors can subvert early events of plant immune signaling that are activated upon recognition of Microbe-Associated Molecular Patterns (MAMPs), the so-called MAMP-triggered immunity (MTI). Here, we describe the isolation and transfection with effector genes of Arabidopsis thaliana and Solanum lycopersicum mesophyll protoplasts, the use of a non-invasive luciferase reporter assay and a simple method to detect activated Mitogen-Activated Protein Kinases (MAPKs) to identify and study, in a medium-throughput manner, new effectors suppressing early signal transduction events of MTI.

  5. Benzophenone Synthase and Chalcone Synthase Accumulate in the Mesophyll of Hypericum perforatum Leaves at Different Developmental Stages

    Science.gov (United States)

    Belkheir, Asma K.; Gaid, Mariam; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2016-01-01

    The active medicinal constituents in Hypericum perforatum, used to treat depression and skin irritation, include flavonoids and xanthones. The carbon skeletons of these compounds are formed by chalcone synthase (CHS) and benzophenone synthase (BPS), respectively. Polyclonal antisera were raised against the polyketide synthases from Hypericum androsaemum and their IgG fractions were isolated. Immunoblotting and immunotitration were used to test the IgGs for crossreactivity and monospecificity in H. perforatum leaf protein extract. Immunofluorescence localization revealed that both CHS and BPS are located in the mesophyll. The maximum fluorescence levels were observed in approx. 0.5 and 1 cm long leaves, respectively. The fluorescence intensity observed for CHS significantly exceeded that for BPS. Using histochemical staining, flavonoids were detected in the mesophyll, indicating that the sites of biosynthesis and accumulation coincide. Our results help understand the biosynthesis and underlying regulation of active H. perforatum constituents. PMID:27446151

  6. Manganese accumulation in the leaf mesophyll of four tree species: a PIXE/EDAX localization study.

    Science.gov (United States)

    Fernando, D R; Bakkaus, E J; Perrier, N; Baker, A J M; Woodrow, I E; Batianoff, G N; Collins, R N

    2006-01-01

    Little is known about the spatial distribution of excess manganese (Mn) in the leaves of tolerant plants. Recently, the first such study of a Mn hyperaccumulator showed that the highest localized Mn concentrations occur in the photosynthetic tissue. This is in contrast to reports based on localization of foliar accumulation of other heavy metals. Here, four tree species, Gossia bidwillii, Virotia neurophylla, Macadamia integrifolia and Macadamia tetraphylla, which hyperaccumulate or strongly accumulate Mn, were studied. Cross-sectional foliar Mn localization was carried out in situ using proton-induced X-ray emission/energy dispersive X-ray analysis (PIXE/EDAX). All four species contained photosynthetic tissues with multiple palisade layers. These were shown to be the primary sequestration sites for Mn. Mn was not detected in the epidermal tissues. The findings of this study demonstrate a concurrence of three traits in four tree species, that is, accumulation of excess Mn in the leaves, its primary sequestration in the photosynthetic tissues, and multiple-layer palisade mesophyll.

  7. Transport of Arginine and Aspartic Acid into Isolated Barley Mesophyll Vacuoles 1

    Science.gov (United States)

    Martinoia, Enrico; Thume, Monika; Vogt, Esther; Rentsch, Doris; Dietz, Karl-Josef

    1991-01-01

    The transport of arginine into isolated barley (Hordeum vulgare L.) mesophyll vacuoles was investigated. In the absence of ATP, arginine uptake was saturable with a Km of 0.3 to 0.4 millimolar. Positively charged amino acids inhibited arginine uptake, lysine being most potent with a Ki of 1.2 millimolar. In the presence of free ATP, but not of its Mg-complex, uptake of arginine was drastically enhanced and a linear function of its concentration up to 16 millimolar. The nonhydrolyzable adenylyl imidodiphosphate, but no other nucleotide tested, could substitute for ATP. Therefore, it is suggested that this process does not require energy and does not involve the tonoplast ATPase. The ATP-dependent arginine uptake was strongly inhibited by p-chloromercuriphenylsulfonic acid. Furthermore, hydrophobic amino acids were inhibitory (I50 phenylalanine 1 millimolar). Similar characteristics were observed for the uptake of aspartic acid. However, rates of ATP-stimulated aspartic acid transport were 10-fold lower as compared to arginine transport. Uptake of aspartate in the absence of ATP was negligible. PMID:16668447

  8. A simple and effective method to encapsulate tobacco mesophyll protoplasts to maintain cell viability

    Directory of Open Access Journals (Sweden)

    Rong Lei

    2015-01-01

    • It is very convenient to change or collect the solution without mechanically disturbing the protoplasts. This simple and effective silica sol–gel/alginate two-step immobilization of protoplasts in Transwell has great potential for applications in genetic transformation, metabolite production, and migration assays.

  9. Direct gene transfer study and transgenic plant regeneration after electroporation into mesophyll protoplasts of Pelargonium x hortorum, 'Panaché Sud'.

    Science.gov (United States)

    Hassanein, Anber; Hamama, Latifa; Loridon, Karine; Dorion, Noëlle

    2009-10-01

    Direct genetic transformation of mesophyll protoplasts was studied in Pelargonium x hortorum. Calcein and green-fluorescent protein (GFP) gene were used to set up the process. Electroporation (three electric pulses from a 33-microF capacitor in a 250-V cm(-1) electric field) was more efficient than PEG 6000 for membrane permeation, protoplast survival and cell division. Transient expression of GFP was detected in 33-36% of electroporated protoplasts after 2 days and further in colonies. A protoplast suspension conductivity of >1,500 microS cm(-1) allowed high colony formation and plant regeneration. Stable transformation was obtained using the plasmid FAJ3000 containing uidA and nptII genes. When selection (50 mg l(-1) kanamycin) was achieved 6 weeks after electroporation, regenerated shoots were able to grow and root on 100 mg l(-1) kanamycin. The maximum transformation efficiency was 4.5%, based on the number of colonies producing kanamycin-resistant rooted plants or 0.7% based on the number of cultured protoplasts. Polymerase chain reaction (PCR) analysis on in vitro micropropagated plants showed that 18 clones out of 20 contained the nptII gene, while the uidA gene was absent. These results were confirmed after PCR analyses of five glasshouse-acclimatized clones.

  10. Isolation, culture and plantlet regeneration from cotyledon and mesophyll protoplasts of two pickling cucumber (Cucumis sativus L.) genotypes.

    Science.gov (United States)

    Punja, Z K; Tang, F A; Sarmento, G G

    1990-07-01

    Optimal protoplast yields from cotyledons (2.0×10(6) protoplasts/ 0.5 g tissue) and from true leaves (5.0×10(6) protoplasts/g tissue) of two Cucumis sativus genotypes were obtained following a 16 h digestion with, respectively, 1.25% pectinase+0.5% Cellulysin and 0.5 % pectinase+ 1.0% Cellulysin. Enzyme solutions were prepared in modified MS medium containing half-strength major salts, full complement of minor salts and vitamins, 2% sucrose and 0.25 M mannitol. A plating density of 3.5-4.0× 10(4) protoplasts/ml or higher was required for sustained division, with first division occurring in 6-7 days, second-third division in 8-9 days, and minicalli formation by day 13. Embedding in 0.4% agarose provided the highest plating efficiency (proportion that formed minicalli) of mesophyll protoplasts, which was 28.3% for genotype 3672 and 15% for genotype 3676. By comparison, liquid culture and droplet culture gave lower plating efficiencies (10-19%). Cotyledon and mesophyll protoplasts of one genotype formed minicalli on MS medium containing 2,4-D/BA at 1.0/2.5 μM and 5.0/5.0 μM, respectively, within 21 days, while mesophyll protoplasts of the second genotype formed minicalli on MS medium containing NAA/BA at 5.0/5.0 μM within 12 days. Shoot buds or somatic embryos were obtained upon subculture of calli to MS medium containing lower concentrations (0.05-0.01 μM) of 2,4-D/BA or NAA/BA and a few plantlets, ca.18, were recovered on hormone-free medium.

  11. Comparative proteomics of chloroplasts envelopes from bundle sheath and mesophyll chloroplasts reveals novel membrane proteins with a possible role in C4-related metabolite fluxes and development.

    Directory of Open Access Journals (Sweden)

    Kalpana eManandhar-Shrestha

    2013-03-01

    Full Text Available As the world population grows, our need for food increases drastically. Limited amounts of arable land lead to a competition between food and fuel crops, while changes in the global climate may impact future crop yields. Thus, a second green revolution will need a better understanding of the processes essential for plant growth and development. One approach toward the solution of this problem is to better understand regulatory and transport processes in C4 plants. C4 plants display an up to 10-fold higher apparent CO2 assimilation and higher yields while maintaining high water use efficiency. This requires differential regulation of mesophyll (M and bundle sheath (BS chloroplast development as well as higher metabolic fluxes of photosynthetic intermediates between cells and across chloroplast envelopes. While previous analyses of overall chloroplast membranes have yielded significant insight, our comparative proteomics approach using enriched BS and M chloroplast envelopes of Zea mays allowed us to identify 37 proteins of unknown function that have not been seen in these earlier studies. We identified 280 proteins, 84% of which are known/predicted to be present in chloroplasts (cp. 74% have a known or predicted membrane association. 21 membrane proteins were 2-15 times more abundant in BS cells, while 36 proteins were more abundant in M cp envelopes. These proteins could represent additional candidates of proteins essential for development or metabolite transport processes in C4 plants. RT-PCR confirmed differential expression of thirteen candidate genes. Cp association was confirmed using GFP labeling. Genes for a PIC-like protein and an ER-AP-like protein show an early transient increase in gene expression during the transition to light. In addition, PIC gene expression is increased in the immature part of the leaf and was lower in the fully developed parts of the leaf, suggesting a need for/incorporation of the protein during chloroplast

  12. Stomatal and mesophyll conductances to CO2 are the main limitations to photosynthesis in sugar beet (Beta vulgaris) plants grown with excess zinc.

    Science.gov (United States)

    Sagardoy, R; Vázquez, S; Florez-Sarasa, I D; Albacete, A; Ribas-Carbó, M; Flexas, J; Abadía, J; Morales, F

    2010-07-01

    *The effects of zinc (Zn) toxicity on photosynthesis and respiration were investigated in sugar beet (Beta vulgaris) plants grown hydroponically with 1.2, 100 and 300 microM Zn. *A photosynthesis limitation analysis was used to assess the stomatal, mesophyll, photochemical and biochemical contributions to the reduced photosynthesis observed under Zn toxicity. *The main limitation to photosynthesis was attributable to stomata, with stomatal conductances decreasing by 76% under Zn excess and stomata being unable to respond to physiological and chemical stimuli. The effects of excess Zn on photochemistry were minor. Scanning electron microscopy showed morphological changes in stomata and mesophyll tissue. Stomatal size and density were smaller, and stomatal slits were sealed in plants grown under high Zn. Moreover, the mesophyll conductance to CO(2) decreased by 48% under Zn excess, despite a marked increase in carbonic anhydrase activity. Respiration, including that through both cytochrome and alternative pathways, was doubled by high Zn. *It can be concluded that, in sugar beet plants grown in the presence of excess Zn, photosynthesis is impaired due to a depletion of CO(2) at the Rubisco carboxylation site, as a consequence of major decreases in stomatal and mesophyll conductances to CO(2).

  13. Changes in photosynthesis, mesophyll conductance to CO2, and isoprenoid emissions in Populus nigra plants exposed to excess nickel.

    Science.gov (United States)

    Velikova, Violeta; Tsonev, Tsonko; Loreto, Francesco; Centritto, Mauro

    2011-05-01

    Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 μM Ni (Ni30 and Ni200). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO2] than in control leaves. However chloroplastic [CO2] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-β-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Senescence vs. changes in nuclear DNA, protein and dry mass contents in leaf mesophyll of two species differing in occurrence of endomitotic polyploidy.

    Science.gov (United States)

    Kuran, H

    1999-01-01

    DNA and Naphtol yellow S-staining (F-NYS) protein contents were measured cytophotometrically using the Feulgen method in the nuclei of the mesophyll from the basal and apical zone of young and old leaves in two perennial monocotyledonous species: Rhoeo discolor and Clivia miniata, differing in presence or absence of DNA endoreplication. Dry mass content was determined interferometrically using an uniform field with large image shearing method. It has been shown that nuclei with 2C DNA and below 2C DNA content dominate in old leaves. The decrease in dry mass content of nuclei correlated with the decrease in NYS protein content. Parallelly a significant increase in NYS protein and DNA contents observed in chromocenters Rhoeo discolor was proportional to the increase in their dry mass. The decrease in nuclear DNA content in mesophyll of old leaves in endoreplicating species was the same as in non-edoreplicating one, however the senescence was more intensive in endoreplicating species.

  15. Asymmetrical effects of mesophyll conductance on fundamental photosynthetic parameters and their relationships estimated from leaf gas exchange measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ying [University of Texas at Austin; Gu, Lianhong [ORNL

    2013-01-01

    Worldwide measurements of nearly 130 C3 species covering all major plant functional types are analyzed in conjunction with model simulations to determine the effects of mesophyll conductance (gm) on photosynthetic parameters and their relationships estimated from A/Ci curves. We find that an assumption of infinite gm results in up to 75% underestimation for maximum carboxylation rate Vcmax, 60% for maximum electron transport rate Jmax, and 40% for triose phosphate utilization rate Tu. Vcmax is most sensitive, Jmax is less sensitive, and Tu has the least sensitivity to the variation of gm. Due to this asymmetrical effect of gm, the ratios of Jmax to Vcmax, Tu to Vcmax, and Tu to Jmax are all overestimated. An infinite gm assumption also limits the freedom of variation of estimated parameters and artificially constrains parameter relationships to stronger shapes. These findings suggest the importance of quantifying gm for understanding in-situ photosynthetic machinery functioning. We show that a nonzero resistance to CO2 movement in chloroplasts has small effects on estimated parameters. A nonlinear function with gm as input is developed to convert the parameters estimated under an assumption of infinite gm to proper values. This function will facilitate gm representation in global carbon cycle models.

  16. Transgenic Rice Expressing Ictb and FBP/Sbpase Derived from Cyanobacteria Exhibits Enhanced Photosynthesis and Mesophyll Conductance to CO2.

    Directory of Open Access Journals (Sweden)

    Han Yu Gong

    Full Text Available To find a way to promote the rate of carbon flux and further improve the photosynthetic rate in rice, two CO2-transporting and fixing relevant genes, Ictb and FBP/Sbpase, which were derived from cyanobacteria with the 35SCaMV promotor in the respective constructs, were transformed into rice. Three homologous transgenic groups with Ictb, FBP/Sbpase and the two genes combined were constructed in parallel, and the functional effects of these two genes were investigated by physiological, biochemical and leaf anatomy analyses. The results indicated that the mesophyll conductance and net photosynthetic rate were higher at approximately 10.5-36.8% and 13.5-34.6%, respectively, in the three groups but without any changes in leaf anatomy structure compared with wild type. Other physiological and biochemical parameters increased with the same trend in the three groups, which showed that the effect of FBP/SBPase on improving photosynthetic capacity was better than that of ICTB and that there was an additive effect in ICTB+FBP/SBPase. ICTB localized in the cytoplasm, whereas FBP/SBPase was successfully transported to the chloroplast. The two genes might show a synergistic interaction to promote carbon flow and the assimilation rate as a whole. The multigene transformation engineering and its potential utility for improving the photosynthetic capacity and yield in rice were discussed.

  17. Asymmetrical effects of mesophyll conductance on fundamental photosynthetic parameters and their relationships estimated from leaf gas exchange measurements.

    Science.gov (United States)

    Sun, Ying; Gu, Lianhong; Dickinson, Robert E; Pallardy, Stephen G; Baker, John; Cao, Yonghui; DaMatta, Fábio Murilo; Dong, Xuejun; Ellsworth, David; Van Goethem, Davina; Jensen, Anna M; Law, Beverly E; Loos, Rodolfo; Martins, Samuel C Vitor; Norby, Richard J; Warren, Jeffrey; Weston, David; Winter, Klaus

    2014-04-01

    Worldwide measurements of nearly 130 C3 species covering all major plant functional types are analysed in conjunction with model simulations to determine the effects of mesophyll conductance (g(m)) on photosynthetic parameters and their relationships estimated from A/Ci curves. We find that an assumption of infinite g(m) results in up to 75% underestimation for maximum carboxylation rate V(cmax), 60% for maximum electron transport rate J(max), and 40% for triose phosphate utilization rate T(u) . V(cmax) is most sensitive, J(max) is less sensitive, and T(u) has the least sensitivity to the variation of g(m). Because of this asymmetrical effect of g(m), the ratios of J(max) to V(cmax), T(u) to V(cmax) and T(u) to J(max) are all overestimated. An infinite g(m) assumption also limits the freedom of variation of estimated parameters and artificially constrains parameter relationships to stronger shapes. These findings suggest the importance of quantifying g(m) for understanding in situ photosynthetic machinery functioning. We show that a nonzero resistance to CO2 movement in chloroplasts has small effects on estimated parameters. A non-linear function with gm as input is developed to convert the parameters estimated under an assumption of infinite gm to proper values. This function will facilitate gm representation in global carbon cycle models. © 2013 John Wiley & Sons Ltd.

  18. Chloroplast downsizing under nitrate nutrition restrained mesophyll conductance and photosynthesis in rice (Oryza sativa L.) under drought conditions.

    Science.gov (United States)

    Li, Yong; Ren, Binbin; Yang, Xiuxia; Xu, Guohua; Shen, Qirong; Guo, Shiwei

    2012-05-01

    The phenomenon whereby ammonium enhances the tolerance of rice seedlings (Oryza sativa L., cv. 'Shanyou 63' hybrid indica China) to water stress has been reported in previous studies. To study the intrinsic mechanism of biomass synthesis related to photosynthesis, hydroponic experiments supplying different nitrogen (N) forms were conducted; water stress was simulated by the addition of polyethylene glycol. Water stress decreased leaf water potential (Ψ(leaf)) under nitrate nutrition, while it had no negative effect under ammonium nutrition. The decreased Ψ(leaf) under nitrate nutrition resulted in chloroplast downsizing and subsequently decreased mesophyll conductance to CO(2) (g(m)). The decreased g(m) and stomatal conductance (g(s)) under nitrate nutrition with water stress restrained the CO(2) supply to the chloroplast and Rubisco. The relatively higher distribution of leaf N to Rubisco under ammonium nutrition might also be of benefit for photosynthesis under water stress. In conclusion, chloroplast downsizing induced a decline in g(m), a relatively higher decrease in g(s) under nitrate nutrition with water stress, restrained the CO(2) supply to Rubisco and finally decreased the photosynthetic rate.

  19. The coordination of ploidy and cell size differs between cell layers in leaves.

    Science.gov (United States)

    Katagiri, Yohei; Hasegawa, Junko; Fujikura, Ushio; Hoshino, Rina; Matsunaga, Sachihiro; Tsukaya, Hirokazu

    2016-04-01

    Growth and developmental processes are occasionally accompanied by multiple rounds of DNA replication, known as endoreduplication. Coordination between endoreduplication and cell size regulation often plays a crucial role in proper organogenesis and cell differentiation. Here, we report that the level of correlation between ploidy and cell volume is different in the outer and inner cell layers of leaves of Arabidopsis thaliana using a novel imaging technique. Although there is a well-known, strong correlation between ploidy and cell volume in pavement cells of the epidermis, this correlation was extremely weak in palisade mesophyll cells. Induction of epidermis cell identity based on the expression of the homeobox gene ATML1 in mesophyll cells enhanced the level of correlation between ploidy and cell volume to near that of wild-type epidermal cells. We therefore propose that the correlation between ploidy and cell volume is regulated by cell identity.

  20. Stomatal and mesophyll conductances to CO₂ in different plant groups: underrated factors for predicting leaf photosynthesis responses to climate change?

    Science.gov (United States)

    Flexas, Jaume; Carriquí, Marc; Coopman, Rafael E; Gago, Jorge; Galmés, Jeroni; Martorell, Sebastià; Morales, Fermín; Diaz-Espejo, Antonio

    2014-09-01

    The climate change conditions predicted for the end of the current century are expected to have an impact on the performance of plants under natural conditions. The variables which are foreseen to have a larger effect are increased CO2 concentration and temperature. Although it is generally considered CO2 assimilation rate could be increased by the increasing levels of CO2, it has been reported in previous studies that acclimation to high CO2 results in reductions of physiological parameters involved in photosynthesis, like the maximum carboxylation rate (Vc,max), stomatal conductance (gs) and mesophyll conductance to CO2 (gm). On the one hand, most of the previous modeling efforts have neglected the potential role played by the acclimation of gm to high CO2 and temperature. On the other hand, the effect of climate change on plant clades other than angiosperms, like ferns, has received little attention, and there are no studies evaluating the potential impact of increasing CO2 and temperature on these species. In this study we predicted responses of several representative species among angiosperms, gymnosperms and ferns to increasing CO2 and temperature. Our results show that species with lower photosynthetic capacity - such as some ferns and gymnosperms - would be proportionally more favored under these foreseen environmental conditions. The main reason for this difference is the lower diffusion limitation imposed by gs and gm in plants having high capacity for photosynthesis among the angiosperms, which reduces the positive effect of increasing CO2. However, this apparent advantage of low-diffusion species would be canceled if the two conductances - gs and gm - acclimate and are down regulated to high CO2, which is basically unknown, especially for gymnosperms and ferns. Hence, for a better understanding of different plant responses to future climate, studies are urged in which the actual photosynthetic response/acclimation to increased CO2 and temperature of

  1. Height-related decreases in mesophyll conductance, leaf photosynthesis and compensating adjustments associated with leaf nitrogen concentrations in Pinus densiflora.

    Science.gov (United States)

    Han, Qingmin

    2011-09-01

    Hydraulic limitations associated with increasing tree height result in reduced foliar stomatal conductance (g(s)) and light-saturated photosynthesis (A(max)). However, it is unclear whether the decline in A(max) is attributable to height-related modifications in foliar nitrogen concentration (N), to mesophyll conductance (g(m)) or to biochemical capacity for photosynthesis (maximum rate of carboxylation, V(cmax)). Simultaneous measurements of gas exchange and chlorophyll fluorescence were made to determine g(m) and V(cmax) in four height classes of Pinus densiflora Sieb. & Zucc. trees. As the average height of growing trees increased from 3.1 to 13.7 m, g(m) decreased from 0.250 to 0.107 mol m(-2) s(-1), and the CO(2) concentration from the intercellular space (C(i)) to the site of carboxylation (C(c)) decreased by an average of 74 µmol mol(-1). Furthermore, V(cmax) estimated from C(c) increased from 68.4 to 112.0 µmol m(-2) s(-1) with the increase in height, but did not change when it was calculated based on C(i). In contrast, A(max) decreased from 14.17 to 10.73 µmol m(-2) s(-1). Leaf dry mass per unit area (LMA) increased significantly with tree height as well as N on both a dry mass and an area basis. All of these parameters were significantly correlated with tree height. In addition, g(m) was closely correlated with LMA and g(s), indicating that increased diffusive resistance for CO(2) may be the inevitable consequence of morphological adaptation. Foliar N per unit area was positively correlated with V(cmax) based on C(c) but negatively with A(max), suggesting that enhancement of photosynthetic capacity is achieved by allocating more N to foliage in order to minimize the declines in A(max). Increases in the N cost associated with carbon gain because of the limited water available to taller trees lead to a trade-off between water use efficiency and photosynthetic nitrogen use efficiency. In conclusion, the height-related decrease in photosynthetic

  2. Implications of the mesophyll conductance to CO2 for photosynthesis and water-use efficiency during long-term water stress and recovery in two contrasting Eucalyptus species.

    Science.gov (United States)

    Cano, F Javier; López, Rosana; Warren, Charles R

    2014-11-01

    Water stress (WS) slows growth and photosynthesis (A(n)), but most knowledge comes from short-time studies that do not account for longer term acclimation processes that are especially relevant in tree species. Using two Eucalyptus species that contrast in drought tolerance, we induced moderate and severe water deficits by withholding water until stomatal conductance (g(sw)) decreased to two pre-defined values for 24 d, WS was maintained at the target g(sw) for 29 d and then plants were re-watered. Additionally, we developed new equations to simulate the effect on mesophyll conductance (g(m)) of accounting for the resistance to refixation of CO(2). The diffusive limitations to CO(2), dominated by the stomata, were the most important constraints to A(n). Full recovery of A(n) was reached after re-watering, characterized by quick recovery of gm and even higher biochemical capacity, in contrast to the slower recovery of g(sw). The acclimation to long-term WS led to decreased mesophyll and biochemical limitations, in contrast to studies in which stress was imposed more rapidly. Finally, we provide evidence that higher gm under WS contributes to higher intrinsic water-use efficiency (iWUE) and reduces the leaf oxidative stress, highlighting the importance of gm as a target for breeding/genetic engineering.

  3. Reconstruction of Metabolic Pathways, Protein Expression, and Homeostasis Machineries across Maize Bundle Sheath and Mesophyll Chloroplasts: Large-Scale Quantitative Proteomics Using the First Maize Genome Assembly1[W][OA

    Science.gov (United States)

    Friso, Giulia; Majeran, Wojciech; Huang, Mingshu; Sun, Qi; van Wijk, Klaas J.

    2010-01-01

    Chloroplasts in differentiated bundle sheath (BS) and mesophyll (M) cells of maize (Zea mays) leaves are specialized to accommodate C4 photosynthesis. This study provides a reconstruction of how metabolic pathways, protein expression, and homeostasis functions are quantitatively distributed across BS and M chloroplasts. This yielded new insights into cellular specialization. The experimental analysis was based on high-accuracy mass spectrometry, protein quantification by spectral counting, and the first maize genome assembly. A bioinformatics workflow was developed to deal with gene models, protein families, and gene duplications related to the polyploidy of maize; this avoided overidentification of proteins and resulted in more accurate protein quantification. A total of 1,105 proteins were assigned as potential chloroplast proteins, annotated for function, and quantified. Nearly complete coverage of primary carbon, starch, and tetrapyrole metabolism, as well as excellent coverage for fatty acid synthesis, isoprenoid, sulfur, nitrogen, and amino acid metabolism, was obtained. This showed, for example, quantitative and qualitative cell type-specific specialization in starch biosynthesis, arginine synthesis, nitrogen assimilation, and initial steps in sulfur assimilation. An extensive overview of BS and M chloroplast protein expression and homeostasis machineries (more than 200 proteins) demonstrated qualitative and quantitative differences between M and BS chloroplasts and BS-enhanced levels of the specialized chaperones ClpB3 and HSP90 that suggest active remodeling of the BS proteome. The reconstructed pathways are presented as detailed flow diagrams including annotation, relative protein abundance, and cell-specific expression pattern. Protein annotation and identification data, and projection of matched peptides on the protein models, are available online through the Plant Proteome Database. PMID:20089766

  4. Light-induced changes in hydrogen, calcium, potassium, and chloride ion fluxes and concentrations from the mesophyll and epidermal tissues of bean leaves. Understanding the ionic basis of light-induced bioelectrogenesis

    Science.gov (United States)

    Shabala; Newman

    1999-03-01

    Noninvasive, ion-selective vibrating microelectrodes were used to measure the kinetics of H+, Ca2+, K+, and Cl- fluxes and the changes in their concentrations caused by illumination near the mesophyll and attached epidermis of bean (Vicia faba L.). These flux measurements were related to light-induced changes in the plasma membrane potential. The influx of Ca2+ was the main depolarizing agent in electrical responses to light in the mesophyll. Changes in the net fluxes of H+, K+, and Cl- occurred only after a significant delay of about 2 min, whereas light-stimulated influx of Ca2+ began within the time resolution of our measurements (5 s). In the absence of H+ flux, light caused an initial quick rise of external pH near the mesophyll and epidermal tissues. In the mesophyll this fast alkalinization was followed by slower, oscillatory pH changes (5-15 min); in the epidermis the external pH increased steadily and reached a plateau 3 min later. We explain the initial alkalinization of the medium as a result of CO2 uptake by photosynthesizing tissue, whereas activation of the plasma membrane H+ pump occurred 1.5 to 2 min later. The epidermal layer seems to be a substantial barrier for ion fluxes but not for CO2 diffusion into the leaf.

  5. Light-Induced Changes in Hydrogen, Calcium, Potassium, and Chloride Ion Fluxes and Concentrations from the Mesophyll and Epidermal Tissues of Bean Leaves. Understanding the Ionic Basis of Light-Induced Bioelectrogenesis1

    Science.gov (United States)

    Shabala, Sergey; Newman, Ian

    1999-01-01

    Noninvasive, ion-selective vibrating microelectrodes were used to measure the kinetics of H+, Ca2+, K+, and Cl− fluxes and the changes in their concentrations caused by illumination near the mesophyll and attached epidermis of bean (Vicia faba L.). These flux measurements were related to light-induced changes in the plasma membrane potential. The influx of Ca2+ was the main depolarizing agent in electrical responses to light in the mesophyll. Changes in the net fluxes of H+, K+, and Cl− occurred only after a significant delay of about 2 min, whereas light-stimulated influx of Ca2+ began within the time resolution of our measurements (5 s). In the absence of H+ flux, light caused an initial quick rise of external pH near the mesophyll and epidermal tissues. In the mesophyll this fast alkalinization was followed by slower, oscillatory pH changes (5–15 min); in the epidermis the external pH increased steadily and reached a plateau 3 min later. We explain the initial alkalinization of the medium as a result of CO2 uptake by photosynthesizing tissue, whereas activation of the plasma membrane H+ pump occurred 1.5 to 2 min later. The epidermal layer seems to be a substantial barrier for ion fluxes but not for CO2 diffusion into the leaf. PMID:10069851

  6. Changes in photosynthesis, mesophyll conductance to CO{sub 2}, and isoprenoid emissions in Populus nigra plants exposed to excess nickel

    Energy Technology Data Exchange (ETDEWEB)

    Velikova, Violeta, E-mail: violet@obzor.bio21.bas.bg [Bulgarian Academy of Sciences, Acad. M. Popov Institute of Plant Physiology, Acad. G. Bonchev, Bl. 21, 1113 Sofia (Bulgaria); Tsonev, Tsonko [Bulgarian Academy of Sciences, Acad. M. Popov Institute of Plant Physiology, Acad. G. Bonchev, Bl. 21, 1113 Sofia (Bulgaria); Loreto, Francesco [Consiglio Nazionale delle Ricerche, Istituto per la Protezione delle Piante, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze (Italy); Centritto, Mauro [Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale, 00015 Monterotondo Scalo (RM) (Italy)

    2011-05-15

    Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 {mu}M Ni (Ni{sub 30} and Ni{sub 200}). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO{sub 2}] than in control leaves. However chloroplastic [CO{sub 2}] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-{beta}-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. - Graphical abstract: Visible damage caused by Ni treatment. 1 - Ni{sub 0} (control plants); 2 - Ni{sub 200}; M = mature and D = developing Populus nigra leaves. Display Omitted Highlights: > We study the effect of Ni pollution on photosynthesis and isoprenoid emissions. > Ni stress significantly decreases photosynthesis. The main limitations are attributed to mesophyll conductance and metabolism impairment. > Constitutive isoprene emission was significantly stimulated in Ni-stressed leaves. Exposure to enhanced Ni concentration induces cis-beta-ocimene and linalool emissions. - The study reveals consequences of Ni stress on plant physiology, namely increasing diffusional limitation to photosynthesis and isoprenoid emissions.

  7. Short-term water stress impacts on stomatal, mesophyll and biochemical limitations to photosynthesis differ consistently among tree species from contrasting climates.

    Science.gov (United States)

    Zhou, Shuangxi; Medlyn, Belinda; Sabaté, Santiago; Sperlich, Dominik; Prentice, I Colin

    2014-10-01

    Predicting the large-scale consequences of drought in contrasting environments requires that we understand how drought effects differ among species originating from those environments. A previous meta-analysis of published experiments suggested that the effects of drought on both stomatal and non-stomatal limitations to photosynthesis may vary consistently among species from different hydroclimates. Here, we explicitly tested this hypothesis with two short-term water stress experiments on congeneric mesic and xeric species. One experiment was run in Australia using Eucalyptus species and the second was run in Spain using Quercus species as well as two more mesic species. In each experiment, plants were grown under moist conditions in a glasshouse, then deprived of water, and gas exchange was monitored. The stomatal response was analysed with a recently developed stomatal model, whose single parameter g1 represents the slope of the relationship between stomatal conductance and photosynthesis. The non-stomatal response was partitioned into effects on mesophyll conductance (gm), the maximum Rubisco activity (Vcmax) and the maximum electron transport rate (Jmax). We found consistency among the drought responses of g1, gm, Vcmax and Jmax, suggesting that drought imposes limitations on Rubisco activity and RuBP regeneration capacity concurrently with declines in stomatal and mesophyll conductance. Within each experiment, the more xeric species showed relatively high g1 under moist conditions, low drought sensitivity of g1, gm, Vcmax and Jmax, and more negative values of the critical pre-dawn water potential at which Vcmax declines most steeply, compared with the more mesic species. These results indicate adaptive interspecific differences in drought responses that allow xeric tree species to continue transpiration and photosynthesis for longer during periods without rain.

  8. Methods of mesophyll conductance estimation: its impact on key biochemical parameters and photosynthetic limitations in phosphorus-stressed soybean across CO2.

    Science.gov (United States)

    Singh, Shardendu K; Reddy, Vangimalla R

    2016-06-01

    Despite the development of various methods, the rapid estimation of mesophyll conductance (gm ) for a large number of samples is still a daunting challenge. Although the accurate estimation of gm is critical to partition photosynthetic limitations by stomatal (Ls ) and mesophyll (Lm ) conductance and by photo-biochemical (Lb ) processes, the impact of various gm estimation methods on this is ambiguous. As phosphorus (P) starvation and elevated CO2 (eCO2 ) strongly affect photosynthetic processes, their combined effect on the proportional changes in these limitations are not well understood. To investigate this, while also evaluating distinct recent methods of gm estimation sharing few common theories and assumptions, soybean was grown under a range of P nutrition at ambient and eCO2 . Methods significantly affected gm and carboxylation efficiency (VCmax ) but not other photosynthetic parameters. In all the methods, all photosynthetic parameters responded similarly to treatments. However, the percentage difference between VCmax assuming finite and infinite gm was highly inconsistent among methods. The primary mechanism responsible for P limitation to soybean photosynthesis was not CO2 diffusion limitations but Lb comprised of reduced chlorophyll, photochemistry and biochemical processes. The eCO2 decreased Lb but increased Lm without affecting Ls across leaf P concentration. Although each method explored advances of our understanding about gm variability, they all require assumptions of varying degrees, which lead to the discrepancy in the gm values. Among the methods, the oxygen sensitivity-based gm estimation appeared to be suitable for the quick assessment of a large number of samples or genotypes. Digital tools are provided for the easy estimation of gm for some methods.

  9. Proton extrusion is an essential signalling component in the HR of epidermal single cells in the barley-powdery mildew interaction

    DEFF Research Database (Denmark)

    Zhou, F.S.; Andersen, C.H.; Burhenne, K.;

    2000-01-01

    between the epidermal cell and underlying mesophyll cells; (2) scavenger treatment reduces HR; (3) treatment of leaves with low-pH (3.5) citrate and succinate buffers causes more cells to undergo HR in the compatible interaction, while treatment with the same buffers at pH 5.5 reduces the number of HR...

  10. Mutation of a chloroplast-targeting signal in Alternanthera mosaic virus TGB3 impairs cell-to-cell movement and eliminates long-distance virus movement.

    Science.gov (United States)

    Lim, Hyoun-Sub; Vaira, Anna Maria; Bae, Hanhong; Bragg, Jennifer N; Ruzin, Steven E; Bauchan, Gary R; Dienelt, Margaret M; Owens, Robert A; Hammond, John

    2010-08-01

    Cell-to-cell movement of potexviruses requires coordinated action of the coat protein and triple gene block (TGB) proteins. The structural properties of Alternanthera mosaic virus (AltMV) TGB3 were examined by methods differentiating between signal peptides and transmembrane domains, and its subcellular localization was studied by Agrobacterium-mediated transient expression and confocal microscopy. Unlike potato virus X (PVX) TGB3, AltMV TGB3 was not associated with the endoplasmic reticulum, and accumulated preferentially in mesophyll cells. Deletion and site-specific mutagenesis revealed an internal signal VL(17,18) of TGB3 essential for chloroplast localization, and either deletion of the TGB3 start codon or alteration of the chloroplast-localization signal limited cell-to-cell movement to the epidermis, yielding a virus that was unable to move into the mesophyll layer. Overexpression of AltMV TGB3 from either AltMV or PVX infectious clones resulted in veinal necrosis and vesiculation at the chloroplast membrane, a cytopathology not observed in wild-type infections. The distinctive mesophyll and chloroplast localization of AltMV TGB3 highlights the critical role played by mesophyll targeting in virus long-distance movement within plants.

  11. The expression of different superoxide dismutase forms is cell-type dependent in olive (Olea europaea L.) leaves.

    Science.gov (United States)

    Corpas, Francisco J; Fernández-Ocaña, Ana; Carreras, Alfonso; Valderrama, Raquel; Luque, Francisco; Esteban, Francisco J; Rodríguez-Serrano, María; Chaki, Mounira; Pedrajas, José R; Sandalio, Luisa M; del Río, Luis A; Barroso, Juan B

    2006-07-01

    Superoxide dismutase (SOD) is a key antioxidant enzyme present in prokaryotic and eukaryotic cells as a first line of defense against the accumulation of superoxide radicals. In olive leaves, the SOD enzymatic system was characterized and was found to be comprised of three isozymes, an Mn-SOD, an Fe-SOD and a CuZn-SOD. Transcript expression analysis of whole leaves showed that the three isozymes represented 82, 17 and 0.8% of the total SOD expressed, respectively. Using the combination of laser capture microdissection (LCM) and real-time quantitative reverse transcription-PCR (RT-PCR), the expression of these SOD isozymes was studied in different cell types of olive leaves, including spongy mesophyll, palisade mesophyll, xylem and phloem. In spongy mesophyll cells, the isozyme proportion was similar to that in whole leaves, but in the other cells the proportion of expressed SOD isozymes was different. In palisade mesophyll cells, Fe-SOD was the most abundant, followed by Mn-SOD and CuZn-SOD, but in phloem cells Mn-SOD was the most prominent isozyme, and Fe-SOD was present in trace amounts. In xylem cells, only the Mn-SOD was detected. On the other hand, the highest accumulation of superoxide radicals was localized in vascular tissue which was the tissue with the lowest level of SOD transcripts. These data show that in olive leaves, each SOD isozyme has a different gene expression depending on the cell type of the leaf.

  12. ISOLATION OF MESOPHYLL PROTOPLASTS FROM MEDITERRANEAN WOODY PLANTS FOR THE STUDY OF DNA INTEGRITY UNDER ABIOTIC STRESS

    Directory of Open Access Journals (Sweden)

    Elena Kuzminsky

    2016-08-01

    Full Text Available Abiotic stresses have considerable negative impact on Mediterranean plant ecosystems and better comprehension of the genetic control of response and adaptation of trees to global changes is urgently needed. The Single Cell Gel Electrophoresis assay could be considered a good estimator of DNA damage in an individual eukaryotic cell. This method has been mainly employed in animal tissues, because the plant cell wall represents an obstacle for the extraction of nuclei; moreover, in Mediterranean woody species, especially in the sclerophyll plants, this procedure can be quite difficult because of the presence of sclerenchyma and hardened cells. On the other hand, these plants represent an interesting material to be studied because of the ability of these plants to tolerate abiotic stress. For instance, holm oak (Quercus ilex L. has been selected as the model plant to identify critical levels of O3 for Southern European forests. Consequently, a quantitative method for the evaluation of cell injury of leaf tissues of this species is required. Optimal conditions for high-yield nuclei isolation were obtained by using protoplast technology and a detailed description of the method is provided and discussed. White poplar (Populus alba L. was used as an internal control for protoplast isolation. Such a method has not been previously reported in newly fully developed leaves of holm oak. This method combined with Single Cell Gel Electrophoresis assay represents a new tool for testing the DNA integrity of leaf tissues in higher plants under stress conditions.

  13. Isolation of Mesophyll Protoplasts from Mediterranean Woody Plants for the Study of DNA Integrity under Abiotic Stress.

    Science.gov (United States)

    Kuzminsky, Elena; Meschini, Roberta; Terzoli, Serena; Pavani, Liliana; Silvestri, Cristian; Choury, Zineb; Scarascia-Mugnozza, Giuseppe

    2016-01-01

    Abiotic stresses have considerable negative impact on Mediterranean plant ecosystems and better comprehension of the genetic control of response and adaptation of trees to global changes is urgently needed. The single cell gel electrophoresis (SCGE) assay could be considered a good estimator of DNA damage in an individual eukaryotic cell. This method has been mainly employed in animal tissues, because the plant cell wall represents an obstacle for the extraction of nuclei; moreover, in Mediterranean woody species, especially in the sclerophyll plants, this procedure can be quite difficult because of the presence of sclerenchyma and hardened cells. On the other hand, these plants represent an interesting material to be studied because of the ability of these plants to tolerate abiotic stress. For instance, holm oak (Quercus ilex L.) has been selected as the model plant to identify critical levels of O3 for Southern European forests. Consequently, a quantitative method for the evaluation of cell injury of leaf tissues of this species is required. Optimal conditions for high-yield nuclei isolation were obtained by using protoplast technology and a detailed description of the method is provided and discussed. White poplar (Populus alba L.) was used as an internal control for protoplast isolation. Such a method has not been previously reported in newly fully developed leaves of holm oak. This method combined with SCGE assay represents a new tool for testing the DNA integrity of leaf tissues in higher plants under stress conditions.

  14. Yellow mosaic symptom caused by the nuclear shuttle protein gene of mungbean yellow mosaic virus is associated with single-stranded DNA accumulation and mesophyll spread of the virus.

    Science.gov (United States)

    Kuruba, B L; Buvani, A P; Veluthambi, K

    Mungbean yellow mosaic virus-[India:Vigna] (MYMV-[IN:Vig]), a blackgram isolate of MYMV, causes yellow mosaic disease in blackgram and mungbean. Two variable DNA-B components, KA22 and KA27, cause distinct symptoms in blackgram [V. mungo (L.) Hepper] with the same DNA-A component. KA22 + DNA-A-agroinoculated blackgram plants displayed yellow mosaic symptom and accumulated high levels of viral single-stranded (ss) DNA. KA27 + DNA-A-agroinoculated blackgram plants displayed severe stunting symptom and accumulated very low levels of viral ssDNA. However, in mungbean [V. radiata (L.) Wilczek], KA27 + DNA-A caused yellow mosaic symptom and a high level of viral ssDNA accumulated. Swapping of KA27 DNA-B with the nuclear shuttle protein gene (NSP) of KA22 DNA-B (KA27xKA22 NSP) caused yellow mosaic symptom in blackgram, suggesting that KA22 NSP is the determinant of yellow mosaic symptom. Interestingly, KA27xKA22 NSP-infected blackgram plants accumulated high levels of viral ssDNA, comparable to that of KA22 DNA-B infection, suggesting that the KA22 NSP is responsible for accumulation of high levels of viral ssDNA. MYMV distribution was studied in blackgram and mungbean plants by leaf tissue hybridization, which showed mesophyll spread of the virus in KA22-infected blackgram leaflets and in KA27-infected mungbean leaflets, both of which displayed yellow mosaic symptom. However, the virus did not accumulate in the mesophyll in the case of KA27-infected blackgram leaflets. Interestingly, the swapped KA27xKA22 NSP-infected blackgram leaflets showed mesophyll accumulation of the virus, suggesting that KA22 NSP determines its mesophyll spread.

  15. Changes in antenna sizes of photosystems during state transitions in granal and stroma-exposed thylakoid membrane of intact chloroplasts in Arabidopsis mesophyll protoplasts.

    Science.gov (United States)

    Kim, Eunchul; Ahn, Tae Kyu; Kumazaki, Shigeichi

    2015-04-01

    In chloroplasts of plants and algae, state transition is an important regulatory mechanism to maintain the excitation balance between PSI and PSII in the thylakoid membrane. Light-harvesting complex II (LHCII) plays a key role as the regulated energy distributor between PSI and PSII. It is widely accepted that LHCII, which is bound to PSII localized mainly in the granal thylakoid, migrates to bind with PSI localized mainly in the stroma-exposed thylakoid under preferential excitation of PSII. The phenomena have been extensively characterized by many methods. However, the exchange of LHCII between PSII and PSI has not been directly observed in vivo at physiological temperatures. Herein we applied fluorescence spectromicroscopy to Arabidopsis mesophyll protoplasts in order to observe in vivo changes in fluorescence spectra of granal and stromal thylakoid regions during the state transition. The microscopic fluorescence spectra obtained from a few sections with different depths were decomposed into PSI and PSII spectra and self-absorption effects were removed. We were able to determine amplitude changes of PSI and PSII in fluorescence spectra solely due to state transition. Subdomain analysis of granal and stromal thylakoid regions clarified variant behaviors in the different regions.

  16. Plant regeneration from mesophyll protoplast of indica rice Qiugui'ai 11 (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    JIANYuyu; JintaanankulSuwan

    1998-01-01

    In the recent decade, plant regeneration from protoplast has been obtained through embryogenic cell suspension cultures of rice. However, not only the establishment of embryogenic call suspension cultures of rice was difficult, but also the protoplasts became less and less regenerable and the genetic change was gradu ally accumulated during the prolonged culture.Since 1976 (Deka.), extensive efforts have been made to induce sustained division and regenerate plants from rnesophyll protoplasts of rice, but not successful.

  17. The effect of osmotic stress on the metabolism in guard cells of Vicia faba L.

    OpenAIRE

    Asai, Naoko

    2000-01-01

    When plant is subjected to drought stress (low water potential caused by drying soil and/or low humidity), stomata are closed mainly by the action of a phytohormone abscisic acid (ABA) which is synthesized in the mesophyll cells or root cells and transported to the stomata. This stomatal closure causes a delay of wilting. Under drought stress,stomatal guard cells are possible to be exposed to low water potential in the substomatal cavity. However, the protective mechanism of guard cells from ...

  18. Comparative conventional- and quantum dot-labelling strategies for LPS binding site detection in Arabidopsis thaliana mesophyll protoplasts

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    Londiwe Siphephise Mgcina

    2015-05-01

    Full Text Available Lipopolysaccharide (LPS from Gram-negative bacteria is recognized as a microbe-associated molecular pattern (MAMP and not only induces an innate immune response in plants, but also stimulates the development of characteristic defense responses. However, identification and characterization of a cell surface LPS-receptor/binding site, as described in mammals, remains elusive in plants. As an amphiphilic, macromolecular lipoglycan, intact LPS potentially contains three MAMP-active regions, represented by the O-polysaccharide chain, the core and the lipid A. Binding site studies with intact labelled LPS were conducted in Arabidopsis thaliana protoplasts and quantified using flow cytometry fluorescence changes. Qdots, which allow non-covalent, hydrophobic labelling were used as a novel strategy in this study and compared to covalent, hydrophilic labelling with Alexa 488. Affinity for LPS-binding sites was clearly demonstrated by concentration-, temperature- and time-dependent increases in protoplast fluorescence following treatment with the labelled LPS. Moreover, this induced fluorescence increase was convincingly reduced following pre-treatment with excess unlabeled LPS, thereby indicating reversibility of LPS binding. Inhibition of the binding process is also reported using endo- and exocytosis inhibitors. Here, we present evidence for the anticipated presence of LPS-specific binding sites in Arabidopsis protoplasts, and furthermore propose Qdots as a more sensitive LPS-labelling strategy in comparison to the conventional Alexa 488 hydrazide label for binding studies.

  19. Longevity of guard cell chloroplasts in falling leaves: implication for stomatal function and cellular aging

    Energy Technology Data Exchange (ETDEWEB)

    Zeiger, E.; Schwartz, A.

    1982-11-12

    Guard cell chloroplasts in senescing leaves from 12 species of perennial trees and three species of annual plants survived considerably longer than their mesophyll counterparts. In Ginkgo biloba, stomata from yellow leaves opened during the day and closed at night; guard cell chloroplasts from these leaves showed fluorescence transients associated with electron transport and photophosphorylation. These findings indicate that guard cell chloroplasts are highly conserved throughout the life-span of the leaf and that leaves retain stomatal control during senescence.

  20. Does ascorbate in the mesophyll cell walls form the first line of defence against ozone? Testing the concept using broad bean (Vicia faba L.).

    Science.gov (United States)

    Turcsányi, E; Lyons, T; Plöchl, M; Barnes, J

    2000-05-01

    Broad bean (Vicia faba L.) plants were exposed, in duplicate controlled environment chambers, to charcoal/Purafil-filtered air (CFA-grown plants) or to 75 nmol mol(-1) ozone (O(3)) for 7 h d(-1) (O(3)-grown plants) for 28 d, and then exposed to 150 nmol mol(-1) O(3 )for 8 h. The concentration of ascorbate (ASC) was determined in leaf extracellular washing fluid (apoplast) and in the residual leaf tissue (symplast) after 0, 4 and 8 h acute fumigation, and after a 16 h "recovery" period in CFA. Changes in stomatal conductance were measured in vivo in order to model pollutant uptake, while the light-saturated rate of CO(2) assimilation (A:(sat)) was recorded as an indicator of O(3)-induced intracellular damage. Measurements of A:(sat) revealed enhanced tolerance to 150 nmol mol(-1) O(3) in plants pre-exposed to the pollutant compared with equivalent plants grown in CFA, consistent with the observed reduction in pollutant uptake due to lower stomatal conductance. The concentration of ASC in the leaf apoplast (ASC(apo)) declined upon O(3)-treatment in both CFA- and O(3)-grown plants, consistent with the oxidation of ASC(apo) under O(3)-stress. Furthermore, the decline in ASC(apo) was reversible in O(3)-grown plants after a 16 h "recovery" period, but not in plants grown in CFA. No significant change in the level and/or redox state of ASC in the symplast (ASC(symp)) was observed in plants exposed to 150 nmol mol(-1) O(3), and there was no difference in the constitutive level of ASC(symp) between CFA- and O(3)-grown plants. Model calculations indicated that the reaction of O(3) with ASC(apo) in the leaves of Vicia faba is potentially sufficient to intercept a substantial proportion (30-40%) of the O(3)entering the plant under environmentally-relevant conditions. The potential role of apoplastic ASC in mediating the tolerance of leaves to O(3) is discussed.

  1. Crabgrass (Digitaria sanguinalis) allelochemicals that interfere with crop growth and the soil microbial community.

    Science.gov (United States)

    Zhou, Bin; Kong, Chui-Hua; Li, Yong-Hua; Wang, Peng; Xu, Xiao-Hua

    2013-06-05

    Three chemicals, veratric acid, maltol, and (−)-loliolide, were isolated from crabgrass and their structures were identified by spectroscopic analysis. The chemicals were detected in crabgrass root exudates and rhizosphere soils, and their concentrations ranged from 0.16 to 8.10 μg/g. At an approximate concentration determined in crabgrass root exudates, all chemicals significantly inhibited the growth of wheat, maize, and soybean and reduced soil microbial biomass carbon. Phospholipid fatty acid profiling showed that veratric acid, maltol, and (−)-loliolide affected the signature lipid biomarkers of soil bacteria, actinobacteria, and fungi, resulting in changes in soil microbial community structures. There were significant relationships between crop growth and soil microbes under the chemicals' application. Chemical-specific changes in the soil microbial community generated negative feedback on crop growth. The results suggest that veratric acid, maltol, and (−)-loliolide released from crabgrass may act as allelochemicals interfering with crop growth and the soil microbial community.

  2. Sudden collapse of vacuoles in Saintpaulia sp. palisade cells induced by a rapid temperature decrease.

    Directory of Open Access Journals (Sweden)

    Noriaki Kadohama

    Full Text Available It is well known that saintpaulia leaf is damaged by the rapid temperature decrease when cold water is irrigated onto the leaf surface. We investigated this temperature sensitivity and the mechanisms of leaf damage in saintpaulia (Saintpaulia sp. cv. 'Iceberg' and other Gesneriaceae plants. Saintpaulia leaves were damaged and discolored when subjected to a rapid decrease in temperature, but not when the temperature was decreased gradually. Sensitivity to rapid temperature decrease increased within 10 to 20 min during pre-incubation at higher temperature. Injury was restricted to the palisade mesophyll cells, where there was an obvious change in the color of the chloroplasts. During a rapid temperature decrease, chlorophyll fluorescence monitored by a pulse amplitude modulated fluorometer diminished and did not recover even after rewarming to the initial temperature. Isolated chloroplasts were not directly affected by the rapid temperature decrease. Intracellular pH was monitored with a pH-dependent fluorescent dye. In palisade mesophyll cells damaged by rapid temperature decrease, the cytosolic pH decreased and the vacuolar membrane collapsed soon after a temperature decrease. In isolated chloroplasts, chlorophyll fluorescence declined when the pH of the medium was lowered. These results suggest that a rapid temperature decrease directly or indirectly affects the vacuolar membrane, resulting in a pH change in the cytosol that subsequently affects the chloroplasts in palisade mesophyll cells. We further confirmed that the same physiological damage occurs in other Gesneriaceae plants. These results strongly suggested that the vacuoles of palisade mesophyll cells collapsed during the initial phase of leaf injury.

  3. Sudden collapse of vacuoles in Saintpaulia sp. palisade cells induced by a rapid temperature decrease.

    Science.gov (United States)

    Kadohama, Noriaki; Goh, Tatsuaki; Ohnishi, Miwa; Fukaki, Hidehiro; Mimura, Tetsuro; Suzuki, Yoshihiro

    2013-01-01

    It is well known that saintpaulia leaf is damaged by the rapid temperature decrease when cold water is irrigated onto the leaf surface. We investigated this temperature sensitivity and the mechanisms of leaf damage in saintpaulia (Saintpaulia sp. cv. 'Iceberg') and other Gesneriaceae plants. Saintpaulia leaves were damaged and discolored when subjected to a rapid decrease in temperature, but not when the temperature was decreased gradually. Sensitivity to rapid temperature decrease increased within 10 to 20 min during pre-incubation at higher temperature. Injury was restricted to the palisade mesophyll cells, where there was an obvious change in the color of the chloroplasts. During a rapid temperature decrease, chlorophyll fluorescence monitored by a pulse amplitude modulated fluorometer diminished and did not recover even after rewarming to the initial temperature. Isolated chloroplasts were not directly affected by the rapid temperature decrease. Intracellular pH was monitored with a pH-dependent fluorescent dye. In palisade mesophyll cells damaged by rapid temperature decrease, the cytosolic pH decreased and the vacuolar membrane collapsed soon after a temperature decrease. In isolated chloroplasts, chlorophyll fluorescence declined when the pH of the medium was lowered. These results suggest that a rapid temperature decrease directly or indirectly affects the vacuolar membrane, resulting in a pH change in the cytosol that subsequently affects the chloroplasts in palisade mesophyll cells. We further confirmed that the same physiological damage occurs in other Gesneriaceae plants. These results strongly suggested that the vacuoles of palisade mesophyll cells collapsed during the initial phase of leaf injury.

  4. Ultrastructure of fusion products from soybean cell culture and sweet clover leaf protoplasts.

    Science.gov (United States)

    Fowke, L C; Rennie, P J; Kirkpatrick, J W; Constabel, F

    1976-01-01

    Protoplasts from cultured cells of soybean (Glycine max L.) and from sweet clover (Melilotus officinalis L.) mesophyll cells were fused with polyethylene glycol and subsequently cultured for six days. The resulting fusion products as well as unfused protoplasts of each parental species regenerated cell walls and divided. The fusion products were characterized by the presence of soybean leucoplasts and sweet clover chloroplasts. The chloroplasts appeared to be degenerating but other cytoplasmic organelles were typical of actively growing plant cells. The fate of individual nuclei could not be determined.

  5. The effects of sooty mold on photosynthesis and mesophyll structure of mahogany (Swietenia macrophylla King., Meliaceae Efeitos da fumagina sobre a fotossíntese e a estrutura do mesofilo de mogno

    Directory of Open Access Journals (Sweden)

    José Pires de Lemos Filho

    2006-01-01

    Full Text Available The aim of present study was to evaluate the effects of the sooty mold on anatomy and photochemical activity of mahogany (Swietenia macrophylla leaves. The photochemical features of shade-developed leaves with or without sooty mold were compared to those of sun leaves using chlorophyll a fluorescence measurements. Leaf anatomy was also evaluated using conventional techniques. The degree of blockage of the photosynthetic active photon flux density (PPFD by sooty mold and its effect on photochemistry were evaluated. Sun leaves showed thick mesophyll with palisade parenchyma disposed in a uniseriate layer, whereas shade leaves showed narrow mesophyll, independently of sooty mold presence. The effective quantum yield (deltaF/Fm' and the apparent electron transport rate (ETR of sun leaves were higher than those of shade leaves. The values of ETR suggested that photochemistry saturation occurred at lower PPFD in shade-grown plants. Lower values of the deltaF/Fm' and, consequently, lower values of ETR were observed in leaves with sooty mold. A reduction of 40% of the incident light was seen due to physical blockage by sooty mold which is presumably responsible for an additional decrease of ETR values. Our data indicated that sooty mold did not directly damage the leaf, but reduce leaf photochemistry capacity, by decreasing light availability.O objetivo do presente estudo foi avaliar os efeitos da fumagina na anatomia e a atividade fotoquímica em folhas de mogno (Swietenia macrophylla King., Meliaceae. Folhas com e sem fumagina desenvolvidas na sombra foram comparadas com as de folhas de sol, para verificar as diferenças em parâmetros fotoquímicos utilizando-se medidas de fluorescência. As amostras de folhas destinadas a estudos anatômicos foram processadas segundo técnicas convencionais. A intensidade de bloqueio da radiação densidade de fótons fotossinteticamente ativos (DFFA pela fumagina e seu efeito sobre a atividade fotoquímica foram

  6. ‘石牌’广藿香叶肉原生质体的分离及纯化%Isolation and Purification of Mesophyll Protoplasts of Pogostem cablin cv. shipaiensis

    Institute of Scientific and Technical Information of China (English)

    莫小路; 邱蔚芬; 黄珊珊; 陈瑜珍; 严振

    2012-01-01

      以‘石牌’广藿香无菌苗叶片为材料,对原生质体分离、纯化方法以及影响因素进行了研究.结果表明:以继代培养12~22 d 的无菌苗顶芽下第3对展开叶片为材料,用0.5%果胶酶、0.2%离析酶和1.5%纤维素酶作用8 h,渗透压调节剂为11%甘露醇,‘石牌’广藿香叶肉原生质体产量达1.85×107个/g fw,活力达89%;原生质体纯化以12%聚蔗糖(Ficoll)漂浮法效果最佳%  Mesophyll protoplasts were isolated and purified from leaves of in vitro propagated Polgostemon cablin (Blanco) Benth. cv. shipaiensis, and different factors affecting protoplasts yield and activity were investigated. The results showed that young leaves of seedling subcultured for 12~22 days in the enzyme solution consisting of 0.5% (w/v) pectolyase Y-23, 0.2%(w/v) Macerozyme R-10 and 1. 5% (w/v) cellulase R-10, in 11% (w/v) mannitol buffered with 0.1% MES and 0.02%CaCl2 for 8 h, the yield was 1.85×107 protoplasts per gram leaves (fresh weight), the viability was above 89%.

  7. Spatial variation in photosynthetic CO(2) carbon and oxygen isotope discrimination along leaves of the monocot triticale (Triticum × Secale) relates to mesophyll conductance and the Péclet effect.

    Science.gov (United States)

    Kodama, Naomi; Cousins, Asaph; Tu, Kevin P; Barbour, Margaret M

    2011-09-01

    Carbon and oxygen isotope discrimination of CO(2) during photosynthesis (Δ(13)C(obs) and Δ(18)O(obs)) were measured along a monocot leaf, triticale (Triticum × Secale). Both Δ(13)C(obs) and Δ(18)O(obs) increased towards the leaf tip. While this was expected for Δ(18)O(obs) , because of progressive enrichment of leaf water associated with the Péclet effect, the result was surprising for Δ(13) C(obs). To explore parameters determining this pattern, we measured activities of key photosynthetic enzymes [ribulose bis-phosphate carboxylase-oxygenase (Rubisco), phosphoenolpyruvate carboxylase (PEPC) and carbonic anhydrase) as well as maximum carboxylation and electron transport rates (V(cmax) and J(max)) along the leaf. Patterns in leaf internal anatomy along the leaf were also quantified. Mesophyll conductance (g(m)) is known to have a strong influence on Δ(13)C(obs) , so we used three commonly used estimation methods to quantify variation in g(m) along the leaf. Variation in Δ(13)C(obs) was correlated with g(m) and chloroplast surface area facing the intercellular air space, but unrelated to photosynthetic enzyme activity. The observed variation could cause errors at higher scales if the appropriate portion of a leaf is not chosen for leaf-level measurements and model parameterization. Our study shows that one-third of the way from the base of the leaf represents the most appropriate portion to enclose in the leaf chamber. © 2011 Blackwell Publishing Ltd.

  8. Electrophoretic assay for ribulose 1,5-bisphosphate carboxylase/oxygenase in guard cells and other leaf cells of Vicia faba L

    Energy Technology Data Exchange (ETDEWEB)

    Tarczynski, M.C.; Outlaw, W.H. Jr.; Arold, N.; Neuhoff, V.; Hampp, R. (Florida State Univ., Tallahassee (USA) Max-Planck-Institute fuer Experimentelle Medizin, Goettingen (West Germany) Universitaet Tuebingen (West Germany))

    1989-04-01

    The ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) contents of guard cells and other cells of Vicia faba L. leaflet were determined. To prevent proteolysis, proteins of frozen protoplast preparations or of cells excised from freeze-dried leaf were extracted directly in a sodium-dodecyl-sulfate-containing solution which was heated immediately after sample addition. Protein profiles of the different cell types were obtained by electrophoresis of the extracts and subsequent densitometry of the stained protein bands. About one-third of the protein of palisade parenchyma and of spongy parenchyma was Rubisco large subunit. Using chlorophyll (Chl):protein ratios previously obtained, we calculate mesophyll contained ca. 22 millimoles Rubisco per mole Chl. In contrast, guard-cell protoplast preparations were calculated to contain from 0.7 to 2.2 millimoles Rubisco per mole Chl. The upper end of this range is an overestimate resulting from contamination by mesophyll and to the method of peak integration. Extracts of excised guard cells were calculated to contain 0.05 to 0.17 millimole Rubisco per mole Chl. We conclude that Rubisco is absent, or virtually so, in guard cells of V. faba.

  9. Myosin inhibitors block accumulation movement of chloroplasts in Arabidopsis thaliana leaf cells.

    Science.gov (United States)

    Paves, H; Truve, E

    2007-01-01

    Chloroplasts alter their distribution within plant cells depending on the external light conditions. Myosin inhibitors 2,3-butanedione monoxime (BDM), N-ethylmaleimide (NEM), and 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-7) were used to study the possible role of myosins in chloroplast photorelocation in Arabidopsis thaliana mesophyll cells. None of these agents had an effect on the chloroplast high-fluence-rate avoidance movement but all of the three myosin inhibitors blocked the accumulation movement of chloroplasts after a high-fluence-rate irradiation of the leaves. The results suggest that myosins have a role in A. thaliana chloroplast photorelocation.

  10. Mesophylic and psychrophilic digestion of liquid manure.

    NARCIS (Netherlands)

    Zeeman, G.

    1991-01-01

    IN GENERALIn this thesis the possibilities for digestion of cow and pig manure are described for a completely stirred tank reactor system (CSTR) and an accumulation system (AC-system).For this purpose were researched:1. Anaerobic digestion of cow manure. Optimization of the digestio

  11. In vivo quantification of cell coupling in plants with different phloem-loading strategies.

    Science.gov (United States)

    Liesche, Johannes; Schulz, Alexander

    2012-05-01

    Uptake of photoassimilates into the leaf phloem is the key step in carbon partitioning and phloem transport. Symplasmic and apoplasmic loading strategies have been defined in different plant taxa based on the abundance of plasmodesmata between mesophyll and phloem. For apoplasmic loading to occur, an absence of plasmodesmata is a sufficient but not a necessary criterion, as passage of molecules through plasmodesmata might well be blocked or restricted. Here, we present a noninvasive, whole-plant approach to test symplasmic coupling and quantify the intercellular flux of small molecules using photoactivation microscopy. Quantification of coupling between all cells along the prephloem pathways of the apoplasmic loader Vicia faba and Nicotiana tabacum showed, to our knowledge for the first time in vivo, that small solutes like sucrose can diffuse through plasmodesmata up to the phloem sieve element companion cell complex (SECCC). As expected, the SECCC was found to be symplasmically isolated for small solutes. In contrast, the prephloem pathway of the symplasmic loader Cucurbita maxima was found to be well coupled with the SECCC. Phloem loading in gymnosperms is not well understood, due to a profoundly different leaf anatomy and a scarcity of molecular data compared with angiosperms. A cell-coupling analysis for Pinus sylvestris showed high symplasmic coupling along the entire prephloem pathway, comprising at least seven cell border interfaces between mesophyll and sieve elements. Cell coupling together with measurements of leaf sap osmolality indicate a passive symplasmic loading type. Similarities and differences of this loading type with that of angiosperm trees are discussed.

  12. Light-stimulated cell expansion in bean (Phaseolus vulgaris L.) leaves. I. Growth can occur without photosynthesis

    Science.gov (United States)

    Van Volkenburgh, E.; Cleland, R. E.

    1990-01-01

    Cell expansion in dicotyledonous leaves is strongly stimulated by bright white light (WL), at least in part as a result of light-induced acidification of the cell walls. It has been proposed that photosynthetic reactions are required for light-stimulated transport processes across plasma membranes of leaf cells, including proton excretion. The involvement of photosynthesis in growth and wall acidification of primary leaves of bean has been tested by inhibiting photosynthesis in two ways: by reducing chlorophyll content of intact plants with tentoxin (TX) and by treating leaf discs with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Exposure to bright WL stimulated growth of intact leaves of TX-treated plants. Discs excised from green as well as from TX-or DCMU-treated leaves also responded by growing faster in WL, as long as exogenous sucrose was supplied to the photosynthetically inhibited tissues. The WL caused acidification of the epidermal surface of intact TX-leaves, but acidification of the incubation medium by mesophyll cells only occurred when photosynthesis was not inhibited. It is concluded that light-stimulated cell enlargement of bean leaves, and the necessary acidification of epidermal cell walls, are mediated by a pigment other than chlorophyll. Light-induced proton excretion by mesophyll cells, on the other hand, may require both a photosynthetic product (or exogenous sugars) and a non-photosynthetic light effect.

  13. Application of the comet assay in studies of programmed cell death (PCD in plants

    Directory of Open Access Journals (Sweden)

    Maria Charzyńska

    2014-01-01

    Full Text Available Programmed cell death (PCD in plants is an intensively investigated process. One of the main characteristics of PCD in both animal and plant organisms is the non-random, internucleosomal fragmentation of nuclear DNA, usually analysed using total DNA gel electrophoresis or TUNEL method. In this paper we present application of the "comet assay" (Single Cell Gel Electrophoresis for detection of nDNA degradation in studies of PCD during plant life cycle. We analyzed three types of tissue: anther tapetum, endosperm and mesophyll which were prepared in different ways to obtain a suspension of viable cells (without cell walls. The comet assay gives a possibility of examination of the nDNA degradation in individual cell. This method is significant for studies of the plant tissue differentiation and senescence especially in the cases when it is not possible to isolate large number of cells at the same developmental stage.

  14. 激发子诱发的小麦叶肉细胞原生质体[Ca2+]cyt升高主要源于胞外钙离子内流%Elicitor-Induced [Ca2+]cyt Elevation Mainly Depends on Ca2+Influx in Meso-phyll Protoplasts of Wheat

    Institute of Scientific and Technical Information of China (English)

    刘刚; 刘娜; 王冬梅

    2015-01-01

    Combining confocal laser scanning microscope (CLSM) with pharmacology experiment, the elici-tor-induced [Ca2+]cyt dynamics in wheat (Triticum aestivum) mesophyll protoplast were observed for further re-search of intracellular calcium sources. Calcium concentration of mesophyll protoplast in wheat cultivar‘Lovrin 10’ (resistant) showed a trend of distinctly ascend and later descend after intercellular washing fluid (IWF) treatment. Whereas in‘Zhengzhou 5389’ (susceptible), the trend was inconspicuous. Calcium channel inhibitor was used to elucidate the sources of [Ca2+]cyt elevation in protoplast, which resulted in a reduced increasing rate of [Ca2+]cyt dynamics. The results indicates that elicitor-induced [Ca2+]cyt rise in wheat mesophyll protoplast is mainly from extracellular Ca2+inlfux.%以小麦叶肉细胞原生质体-激发子互作为研究体系,借助共聚焦激光扫描显微镜观察结合药物学试验,对激发子刺激后不同抗叶锈性小麦品种原生质体[Ca2+]cyt的动态变化和[Ca2+]cyt升高的钙来源进行了研究。结果表明:抗叶锈小麦品种‘洛夫林10’的原生质体在激发子处理后,[Ca2+]cyt明显升高,随后有所下降,但在试验检测时间范围内仍保持较高浓度水平;而感病品种‘郑州5389’经激发子处理后,[Ca2+]cyt只发生轻微的波动。使用质膜钙通道抑制剂抑制胞外钙离子流入胞内,再经激发子处理,原生质体[Ca2+]cyt虽也有升高,但升高幅度大大降低。这一结果表明,激发子刺激诱发的[Ca2+]cyt升高主要源于胞外钙离子内流。

  15. NaCl effect on the distribution of wall ingrowth polymers and arabinogalactan proteins in type A transfer cells of Medicago sativa Gabès leaves.

    Science.gov (United States)

    Boughanmi, Néziha; Thibault, Florence; Decou, Raphael; Fleurat-Lessard, Pierrette; Béré, Emile; Costa, Guy; Lhernould, Sabine

    2010-06-01

    We studied the distribution of wall ingrowth (WI) polymers by probing thin sections of companion cells specialized as transfer cells in minor veins of Medicago sativa cv Gabès blade with affinity probes and antibodies specific to polysaccharides and glycoproteins. The wall polymers in the controls were similar in WIs and in the primary wall but differently distributed. The extent of labeling in these papillate WIs differed for JIM5 and JIM7 homogalacturonans but was in the same range for LM5 and LM6 rhamnogalacturonans and xyloglucans. These data show that WI enhancement probably requires arabinogalactan proteins (JIM8) mainly localized on the outer part of the primary wall and WIs. By comparison, NaCl-treated plants exhibited cell wall polysaccharide modifications indicating (1) an increase in unesterified homogalacturonans (JIM5), probably implicated in Na(+) binding and/or polysaccharide network interaction for limiting turgor variations in mesophyll cells; (2) enhancement of the xyloglucan network with an accumulation of fucosylated xyloglucans (CCRC-M1) known to increase the capacity of cellulose binding; and (3) specific recognition of JIM8 arabinogalactan proteins that could participate in both wall enlargement and cohesion by increasing the number of molecular interactions with the other polymers. In conclusion, the cell wall polysaccharide distribution in enlarged WIs might (1) participate in wall resistance to sequestration of Na(+), allowing a better control of hydric homeostasis in mesophyll cells to maintain metabolic activity in source leaves, and (2) maintain tolerance of M. sativa to NaCl.

  16. Inconsistency of mesophyll conductance estimate causes the inconsistency for the estimates of maximum rate of Rubisco carboxylation among the linear, rectangular and non-rectangular hyperbola biochemical models of leaf photosynthesis--a case study of CO₂ enrichment and leaf aging effects in soybean.

    Science.gov (United States)

    Sun, Jindong; Feng, Zhaozhong; Leakey, Andrew D B; Zhu, Xinguang; Bernacchi, Carl J; Ort, Donald R

    2014-09-01

    The responses of CO2 assimilation to [CO2] (A/Ci) were investigated at two developmental stages (R5 and R6) and in several soybean cultivars grown under two levels of CO2, the ambient level of 370 μbar versus the elevated level of 550 μbar. The A/Ci data were analyzed and compared by either the combined iterations or the separated iterations of the Rubisco-limited photosynthesis (Ac) and/or the RuBP-limited photosynthesis (Aj) using various curve-fitting methods: the linear 2-segment model; the non-rectangular hyperbola model; the rectangular hyperbola model; the constant rate of electron transport (J) method and the variable J method. Inconsistency was found among the various methods for the estimation of the maximum rate of carboxylation (Vcmax), the mitochondrial respiration rate in the light (Rd) and mesophyll conductance (gm). The analysis showed that the inconsistency was due to inconsistent estimates of gm values that decreased with an instantaneous increase in [CO2], and varied with the transition Ci cut-off between Rubisco-limited photosynthesis and RuBP-regeneration-limited photosynthesis, and due to over-parameters for non-linear curve-fitting with gm included. We proposed an alternate solution to A/Ci curve-fitting for estimates of Vcmax, Rd, Jmax and gm with the various A/Ci curve-fitting methods. The study indicated that down-regulation of photosynthetic capacity by elevated [CO2] and leaf aging was due to partially the decrease in the maximum rates of carboxylation and partially the decrease in gm. Mesophyll conductance lowered photosynthetic capacity by 18% on average for the case of soybean plants.

  17. Clinostation influence on regeneration of cell wall in Solanum Tuberosum L. protoplasts

    Science.gov (United States)

    Nedukha, Elena M.; Sidorov, V. A.; Samoylov, V. M.

    1994-08-01

    Regeneration of cell walls in protoplasts was investigated using light- and electronmicroscopic methods. The protoplasts were isolated from mesophyll of Solanum tuberosum leaves and were cultivated on the horizontal low rotating clinostat (2 rpm) and in control for 10 days. Using a fluorescent method (with Calcofluor white) it was demonstrated that changes in vector gravity results in an regeneration inhibition of cell wall. With electron-microscopical and electro-cytochemical methods (staining with alcianum blue) dynamics of the regeneration of cell walls in protoplasts was studied; carbohydrate matrix of cell walls is deposited at the earliest stages of this process. The influence of microgravity on the cell wall regeneration is discussed in higher plants.

  18. SCARECROW, SCR-LIKE 23 and SHORT-ROOT control bundle sheath cell fate and function in Arabidopsis thaliana.

    Science.gov (United States)

    Cui, Hongchang; Kong, Danyu; Liu, Xiuwen; Hao, Yueling

    2014-04-01

    Bundle sheath (BS) cells form a single cell layer surrounding the vascular tissue in leaves. In C3 plants, photosynthesis occurs in both the BS and mesophyll cells, but the BS cells are the major sites of photosynthesis in C4 plants, whereas the mesophyll cells are only involved in CO2 fixation. Because C4 plants are more efficient photosynthetically, introduction of the C4 mechanism into C3 plants is considered a key strategy to improve crop yield. One prerequisite for such C3-to-C4 engineering is the ability to manipulate the number and physiology of the BS cells, but the molecular basis of BS cell-fate specification remains unclear. Here we report that mutations in three GRAS family transcription factors, SHORT-ROOT (SHR), SCARECROW (SCR) and SCARECROW-LIKE 23 (SCL23), affect BS cell fate in Arabidopsis thaliana. SCR and SCL23 are expressed specifically in the BS cells and act redundantly in BS cell-fate specification, but their expression pattern and function diverge at later stages of leaf development. Using ChIP-chip experiments and sugar assays, we show that SCR is primarily involved in sugar transport whereas SCL23 functions in mineral transport. SHR is also essential for BS cell-fate specification, but it is expressed in the central vascular tissue. However, the SHR protein moves into the BS cells, where it directly regulates SCR and SCL23 expression. SHR, SCR and SCL23 homologs are present in many plant species, suggesting that this developmental pathway for BS cell-fate specification is likely to be evolutionarily conserved.

  19. Spent metal working fluids produced alterations on photosynthetic parameters and cell-ultrastructure of leaves and roots of maize plants.

    Science.gov (United States)

    Grijalbo, Lucía; Fernandez-Pascual, Mercedes; García-Seco, Daniel; Gutierrez-Mañero, Francisco Javier; Lucas, Jose Antonio

    2013-09-15

    In this work we assess the capacity of maize (Zea mays) plants to phytoremediate spent metal working fluids (MWFs) and its effects on photosynthesis and ultrastructure of mesophyll and root cells. A corn-esparto fibre system patented by us has been used to phytoremediate MWFs in hydroponic culture. Furthermore, a plant growth promoting rhizobacteria (PGPR) has been used to improve the process. The results show that this system is capable of significantly reducing the chemical oxygen demand, under local legislation limits. However, plant systems are really damaged, mainly its photosynthetic system, as shown by the photosynthetical parameters. Nevertheless, strain inoculated improves these parameters, especially Hill reaction. The ultrastructure of photosynthetic apparatus was also affected. Chloroplast number decreased and becomes degraded in the mesophyll of MWFs treated plants. In some cases even plasmolysis of chloroplast membrane was detected. Early senescence symptoms were detected in root ultrastructural study. Severe cellular damage was observed in the parenchymal root cells of plants grown with MWFs, while vascular bundles cell remained unchanged. It seems that the inoculation minimises the damage originated by the MWFs pollutants, appearing as less degenerative organelles and higher chloroplast number than in non-inoculated ones. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Three-dimensional patterns of cell division and expansion throughout the development of Arabidopsis thaliana leaves.

    Science.gov (United States)

    Kalve, Shweta; Fotschki, Joanna; Beeckman, Tom; Vissenberg, Kris; Beemster, Gerrit T S

    2014-12-01

    Variations in size and shape of multicellular organs depend on spatio-temporal regulation of cell division and expansion. Here, cell division and expansion rates were quantified relative to the three spatial axes in the first leaf pair of Arabidopsis thaliana. The results show striking differences in expansion rates: the expansion rate in the petiole is higher than in the leaf blade; expansion rates in the lateral direction are higher than longitudinal rates between 5 and 10 days after stratification, but become equal at later stages of leaf blade development; and anticlinal expansion co-occurs with, but is an order of magnitude slower than periclinal expansion. Anticlinal expansion rates also differed greatly between tissues: the highest rates occurred in the spongy mesophyll and the lowest in the epidermis. Cell division rates were higher and continued for longer in the epidermis compared with the palisade mesophyll, causing a larger increase of palisade than epidermal cell area over the course of leaf development. The cellular dynamics underlying the effect of shading on petiole length and leaf thickness were then investigated. Low light reduced leaf expansion rates, which was partly compensated by increased duration of the growth phase. Inversely, shading enhanced expansion rates in the petiole, so that the blade to petiole ratio was reduced by 50%. Low light reduced leaf thickness by inhibiting anticlinal cell expansion rates. This effect on cell expansion was preceded by an effect on cell division, leading to one less layer of palisade cells. The two effects could be uncoupled by shifting plants to contrasting light conditions immediately after germination. This extended kinematic analysis maps the spatial and temporal heterogeneity of cell division and expansion, providing a framework for further research to understand the molecular regulatory mechanisms involved.

  1. Microanalysis of Plant Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  2. The phosphoenolpyruvate/phosphate translocator is required for phenolic metabolism, palisade cell development, and plastid-dependent nuclear gene expression.

    Science.gov (United States)

    Streatfield, S J; Weber, A; Kinsman, E A; Häusler, R E; Li, J; Post-Beittenmiller, D; Kaiser, W M; Pyke, K A; Flügge, U I; Chory, J

    1999-09-01

    The Arabidopsis chlorophyll a/b binding protein (CAB) gene underexpressed 1 (cue1) mutant underexpresses light-regulated nuclear genes encoding chloroplast-localized proteins. cue1 also exhibits mesophyll-specific chloroplast and cellular defects, resulting in reticulate leaves. Both the gene underexpression and the leaf cell morphology phenotypes are dependent on light intensity. In this study, we determine that CUE1 encodes the plastid inner envelope phosphoenolpyruvate/phosphate translocator (PPT) and define amino acid residues that are critical for translocator function. The biosynthesis of aromatics is compromised in cue1, and the reticulate phenotype can be rescued by feeding aromatic amino acids. Determining that CUE1 encodes PPT indicates the in vivo role of the translocator in metabolic partitioning and reveals a mesophyll cell-specific requirement for the translocator in Arabidopsis leaves. The nuclear gene expression defects in cue1 suggest that a light intensity-dependent interorganellar signal is modulated through metabolites dependent on a plastid supply of phosphoenolpyruvate.

  3. Cells

    Directory of Open Access Journals (Sweden)

    Zhao-Hui Jin

    2012-11-01

    Full Text Available As cancer stem cells (CSCs are postulated to play critical roles in cancer development, including metastasis and recurrence, CSC imaging would provide valuable information for cancer treatment and lead to CSC-targeted therapy. To assess the possibility of in vivo CSC targeting, we conducted basic studies on radioimmunotargeting of cancer cells positive for CD133, a CSC marker recognized in various cancers. Antibodies against CD133 were labeled with 125I, and their in vitro cell binding properties were tested. Using the same isotype IgG as a control, in vivo biodistribution of the labeled antibody retaining immunoreactivity was examined in mice bearing an HCT116 xenograft in which a population of the cancer cells expressed CD133. Intratumoral distribution of the labeled antibody was examined and compared to the CD133 expression pattern. The 125I-labeled anti-CD133 antibody showed a modest but significantly higher accumulation in the HCT116 xenograft compared to the control IgG. The intratumoral distribution of the labeled antibody mostly overlapped with the CD133 expression, whereas the control IgG was found in the area close to the necrotic tumor center. Our results indicate that noninvasive in vivo targeting of CSCs could be possible with radiolabeled antibodies against cell membrane markers.

  4. ATML1 promotes epidermal cell differentiation in Arabidopsis shoots.

    Science.gov (United States)

    Takada, Shinobu; Takada, Nozomi; Yoshida, Ayaka

    2013-05-01

    Molecular mechanisms that generate distinct tissue layers in plant shoots are not well understood. ATML1, an Arabidopsis homeobox gene, is expressed in the outermost cell layer, beginning at an early stage of development. The promoters of many epidermis-specific genes, including ATML1, contain an ATML1-binding site called an L1 box, suggesting that ATML1 regulates epidermal cell fate. Here, we show that overexpression of ATML1 was sufficient to activate the expression of epidermal genes and to induce epidermis-related traits such as the formation of stomatal guard cells and trichome-like cells in non-epidermal seedling tissues. Detailed observation of the division planes of these ectopic stomatal cells suggested that a near-surface position, as well as epidermal cell identity, were required for regular anticlinal cell division, as seen in wild-type epidermis. Moreover, analyses of a loss-of-function mutant and overexpressors implied that differentiation of epidermal cells was associated with repression of mesophyll cell fate. Collectively, our studies contribute new information about the molecular basis of cell fate determination in different layers of plant aerial organs.

  5. A novel system for xylem cell differentiation in Arabidopsis thaliana.

    Science.gov (United States)

    Kondo, Yuki; Fujita, Takashi; Sugiyama, Munetaka; Fukuda, Hiroo

    2015-04-01

    During vascular development, procambial and cambial cells give rise to xylem and phloem cells. Because the vascular tissue is deeply embedded, it has been difficult to analyze the processes of vascular development in detail. Here, we establish a novel in vitro experimental system in which vascular development is induced in Arabidopsis thaliana leaf-disk cultures using bikinin, an inhibitor of glycogen synthase kinase 3 proteins. Transcriptome analysis reveals that mesophyll cells in leaf disks synchronously turn into procambial cells and then differentiate into tracheary elements. Leaf-disk cultures from plants expressing the procambial cell markers TDR(pro):GUS and TDR(pro):YFP can be used for spatiotemporal visualization of procambial cell formation. Further analysis with the tdr mutant and TDIF (tracheary element differentiation inhibitory factor) indicates that the key signaling TDIF-TDR-GSK3s regulates xylem differentiation in leaf-disk cultures. This new culture system can be combined with analysis using the rich material resources for Arabidopsis including cell-marker lines and mutants, thus offering a powerful tool for analyzing xylem cell differentiation. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  6. Effects of mutations in the Arabidopsis Cold Shock Domain Protein 3 (AtCSP3) gene on leaf cell expansion.

    Science.gov (United States)

    Yang, Yongil; Karlson, Dale

    2012-08-01

    The cold shock domain is among the most evolutionarily conserved nucleic acid binding domains from prokaryotes to higher eukaryotes, including plants. Although eukaryotic cold shock domain proteins have been extensively studied as transcriptional and post-transcriptional regulators during various developmental processes, their functional roles in plants remains poorly understood. In this study, AtCSP3 (At2g17870), which is one of four Arabidopsis thaliana c old s hock domain proteins (AtCSPs), was functionally characterized. Quantitative RT-PCR analysis confirmed high expression of AtCSP3 in reproductive and meristematic tissues. A homozygous atcsp3 loss-of-function mutant exhibits an overall reduced seedling size, stunted and orbicular rosette leaves, reduced petiole length, and curled leaf blades. Palisade mesophyll cells are smaller and more circular in atcsp3 leaves. Cell size analysis indicated that the reduced size of the circular mesophyll cells appears to be generated by a reduction of cell length along the leaf-length axis, resulting in an orbicular leaf shape. It was also determined that leaf cell expansion is impaired for lateral leaf development in the atcsp3 loss-of-function mutant, but leaf cell proliferation is not affected. AtCSP3 loss-of-function resulted in a dramatic reduction of LNG1 transcript, a gene that is involved in two-dimensional leaf polarity regulation. Transient subcellular localization of AtCSP3 in onion epidermal cells confirmed a nucleocytoplasmic localization pattern. Collectively, these data suggest that AtCSP3 is functionally linked to the regulation of leaf length by affecting LNG1 transcript accumulation during leaf development. A putative function of AtCSP3 as an RNA binding protein is also discussed in relation to leaf development.

  7. Voltage-dependent K channels in protoplasts of trap-lobe cells of Dionaea muscipula.

    Science.gov (United States)

    Iijima, T; Hagiwara, S

    1987-01-01

    The outward rectification of the K+ current in mesophyll cell protoplasts from trap-lobes of Dionaea muscipula was studied with the patch-clamp technique. The rectification had instantaneous and time-dependent components. Changes in [K+]i strongly affected the conductance voltage relation of the plasma membrane while changes in [K+]o had little effect on the relation. Thus, the outward rectification depends on the membrane voltage and the concentration of intracellular K+. Corresponding single-channel activities were observed both in the intact membrane (cell-attached recording) and in excised patches. The single-channel conductance was about 3.3 pS with symmetrical solutions containing 30 mM K+.

  8. Protoplasts: a useful research system for plant cell biology, especially dedifferentiation.

    Science.gov (United States)

    Jiang, Fangwei; Zhu, Jian; Liu, Hai-Liang

    2013-12-01

    As protoplasts have the characteristics of no cell walls, rapid population growth, and synchronicity, they are useful tools for research in many fields, especially cellular biology (Table 1). This article is an overview that focuses on the application of protoplasts to investigate the mechanisms of dedifferentiation, including changes in hormone signals, epigenetic changes, and organelle distribution during the dedifferentiation process. The article also emphasizes the wide range of uses for protoplasts in studying protein positions and signaling during different stresses. The examples provided help to show that protoplast systems, for example the mesophyll protoplast system of Arabidopsis, represent promising tools for studying developmental biology. Meanwhile, specific analysis of protoplast, which comes from different tissue, has specific advantages and limitations (Table 2), and it can provide recommendations to use this system.

  9. A Biogeochemical and Spectral Analysis of Vegetation Affected by External Abiotic Agents: Results of an Investigation from Kitsap County, Washington

    Science.gov (United States)

    1990-12-01

    air spaces developed in the spongy mesophyll of the leaf increase the number of reflecting surfaces with abrupt changes in the index of refraction... mesophyll cells. Although there are several kinds of chlorophylls, chlorophyll a and b are the only important ones in woody plants (Kramer and Kozlowski...with the mesophyll structure. Once the leaf mesophyll is fully developed, small external changes will probably not affect the reflectance. Large

  10. Lower Mississippi River Environmental Program. Report 10. Evaluation of Bird and Mammal Utilization of Dike Systems Along the Lower Mississippi River.

    Science.gov (United States)

    1987-11-01

    Boehmeria cylindrica - + + + + + - - - - Brunnchia cirrhosa - + + + - + + + + + Campsisradicans - - + + - + + + + - Carya illinoensis ...erythrorhizos - - - + + + + + + - Desmanthus illinoensis + + + - - - - Digitaria ischaemum - - - - + - + + + + Digitaria sanguinalis

  11. Determination of the PSI/PSII ratio in living plant cells at room temperature by spectrally resolved fluorescence spectroscopy

    Science.gov (United States)

    Elgass, Kirstin; Zell, Martina; Maurino, Veronica G.; Schleifenbaum, Frank

    2011-02-01

    Leaf cells of living plants exhibit strong fluorescence from chloroplasts, the reaction centers of photosynthesis. Mutations in the photosystems change their structure and can, thus, be monitored by recording the fluorescence spectra of the emitted chlorophyll light. These measurements have, up to now, mostly been carried out at low temperatures (77 K), as these conditions enable the differentiation between the fluorescence of Photosystem I (PSI) and Photosystem II (PSII). In contrast, at room temperature, energy transfer processes between the various photosynthetic complexes result in very similar fluorescence emissions, which mainly consist of fluorescence photons emitted by PSII hindering a discrimination based on spectral ROIs (regions of interest). However, by statistical analysis of high resolution fluorescence spectra recorded at room temperature, it is possible to draw conclusions about the relative PSI/PSII ratio. Here, the possibility of determining the relative PSI/PSII ratio by fluorescence spectroscopy is demonstrated in living maize plants. Bundle-sheath chloroplasts of mature maize plants have a special morphologic characteristic; they are agranal, or exhibit only rudimentary grana, respectively. These chloroplasts are depleted in PSII activity and it could be shown that PSII is progressively reduced during leaf differentiation. A direct comparison of PSII activity in isolated chloroplasts is nearly impossible, since the activity of PSII in both mesophyll- and bundle-sheath chloroplasts decays with time after isolation and it takes significantly longer to isolate bundle-sheath chloroplasts. Considering this fact the measurement of PSI/PSII ratios with the 77K method, which includes taking fluorescence spectra from a diluted suspension of isolated chloroplasts at 77K, is questionable. These spectra are then used to analyze the distribution of energy between PSI and PSII. After rapid cooling to 77K secondary biochemical influences, which attenuate the

  12. A large population of small chloroplasts in tobacco leaf cells allows more effective chloroplast movement than a few enlarged chloroplasts.

    Science.gov (United States)

    Jeong, Won Joong; Park, Youn-Il; Suh, KyeHong; Raven, John A; Yoo, Ook Joon; Liu, Jang Ryol

    2002-05-01

    We generated transgenic tobacco (Nicotiana tabacum cv Xanthi) plants that contained only one to three enlarged chloroplasts per leaf mesophyll cell by introducing NtFtsZ1-2, a cDNA for plastid division. These plants were used to investigate the advantages of having a large population of small chloroplasts rather than a few enlarged chloroplasts in a leaf mesophyll cell. Despite the similarities in photosynthetic components and ultrastructure of photosynthetic machinery between wild-type and transgenic plants, the overall growth of transgenic plants under low- and high-light conditions was retarded. In wild-type plants, the chloroplasts moved toward the face position under low light and toward the profile position under high-light conditions. However, chloroplast rearrangement in transgenic plants in response to light conditions was not evident. In addition, transgenic plant leaves showed greatly diminished changes in leaf transmittance values under both light conditions, indicating that chloroplast rearrangement was severely retarded. Therefore, under low-light conditions the incomplete face position of the enlarged chloroplasts results in decreased absorbance of light energy. This, in turn, reduces plant growth. Under high-light conditions, the amount of absorbed light exceeds the photosynthetic utilization capacity due to the incomplete profile position of the enlarged chloroplasts, resulting in photodamage to the photosynthetic machinery, and decreased growth. The presence of a large number of small and/or rapidly moving chloroplasts in the cells of higher land plants permits more effective chloroplast phototaxis and, hence, allows more efficient utilization of low-incident photon flux densities. The photosynthetic apparatus is, consequently, protected from damage under high-incident photon flux densities.

  13. A single-cell bioluminescence imaging system for monitoring cellular gene expression in a plant body.

    Science.gov (United States)

    Muranaka, Tomoaki; Kubota, Saya; Oyama, Tokitaka

    2013-12-01

    Gene expression is a fundamental cellular process and expression dynamics are of great interest in life science. We succeeded in monitoring cellular gene expression in a duckweed plant, Lemna gibba, using bioluminescent reporters. Using particle bombardment, epidermal and mesophyll cells were transfected with the luciferase gene (luc+) under the control of a constitutive [Cauliflower mosaic virus 35S (CaMV35S)] and a rhythmic [Arabidopsis thaliana CIRCADIAN CLOCK ASSOCIATED 1 (AtCCA1)] promoter. Bioluminescence images were captured using an EM-CCD (electron multiply charged couple device) camera. Luminescent spots of the transfected cells in the plant body were quantitatively measured at the single-cell level. Luminescence intensities varied over a 1,000-fold range among CaMV35S::luc+-transfected cells in the same plant body and showed a log-normal-like frequency distribution. We monitored cellular gene expression under light-dark conditions by capturing bioluminescence images every hour. Luminescence traces of ≥50 individual cells in a frond were successfully obtained in each monitoring procedure. Rhythmic and constitutive luminescence behaviors were observed in cells transfected with AtCCA1::luc+ and CaMV35S::luc+, respectively. Diurnal rhythms were observed in every AtCCA1::luc+-introduced cell with traceable luminescence, and slight differences were detected in their rhythmic waveforms. Thus the single-cell bioluminescence monitoring system was useful for the characterization of cellular gene expression in a plant body.

  14. Over-expression of Arabidopsis CAP causes decreased cell expansion leading to organ size reduction in transgenic tobacco plants.

    Science.gov (United States)

    Barrero, Roberto A; Umeda, Masaaki; Yamamura, Saburo; Uchimiya, Hirofumi

    2003-04-01

    Cyclase-associated proteins (CAP) are multifunctional proteins involved in Ras-cAMP signalling and regulation of the actin cytoskeleton. It has recently been demonstrated that over-expression of AtCAP1 in transgenic arabidopsis plants causes severe morphological defects owing to loss of actin filaments. To test the generality of the function of AtCAP1 in plants, transgenic tobacco plants over-expressing an arabidopsis CAP (AtCAP1) under the regulation of a glucocorticoid-inducible promoter were produced. Over-expression of AtCAP1 in transgenic tobacco plants led to growth abnormalities, in particular a reduction in the size of leaves. Morphological alterations in leaves were the result of reduced elongation of epidermal and mesophyll cells.

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

    Science.gov (United States)

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

    2016-07-01

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

  16. Arabidopsis CAP regulates the actin cytoskeleton necessary for plant cell elongation and division.

    Science.gov (United States)

    Barrero, Roberto A; Umeda, Masaaki; Yamamura, Saburo; Uchimiya, Hirofumi

    2002-01-01

    An Arabidopsis cDNA (AtCAP1) that encodes a predicted protein of 476 amino acids highly homologous with the yeast cyclase-associated protein (CAP) was isolated. Expression of AtCAP1 in the budding yeast CAP mutant was able to rescue defects such as abnormal cell morphology and random budding pattern. The C-terminal domain, 158 amino acids of AtCAP1 possessing in vitro actin binding activity, was needed for the regulation of cytoskeleton-related defects of yeast. Transgenic plants overexpressing AtCAP1 under the regulation of a glucocorticoid-inducible promoter showed different levels of AtCAP1 accumulation related to the extent of growth abnormalities, in particular size reduction of leaves as well as petioles. Morphological alterations in leaves were attributable to decreased cell size and cell number in both epidermal and mesophyll cells. Tobacco suspension-cultured cells (Bright Yellow 2) overexpressing AtCAP1 exhibited defects in actin filaments and were unable to undergo mitosis. Furthermore, an immunoprecipitation experiment suggested that AtCAP1 interacted with actin in vivo. Therefore, AtCAP1 may play a functional role in actin cytoskeleton networking that is essential for proper cell elongation and division.

  17. Guard cell chloroplasts are essential for blue light-dependent stomatal opening in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Noriyuki Suetsugu

    Full Text Available Blue light (BL induces stomatal opening through the activation of H+-ATPases with subsequent ion accumulation in guard cells. In most plant species, red light (RL enhances BL-dependent stomatal opening. This RL effect is attributable to the chloroplasts of guard cell, the only cells in the epidermis possessing this organelle. To clarify the role of chloroplasts in stomatal regulation, we investigated the effects of RL on BL-dependent stomatal opening in isolated epidermis, guard cell protoplasts, and intact leaves of Arabidopsis thaliana. In isolated epidermal tissues and intact leaves, weak BL superimposed on RL enhanced stomatal opening while BL alone was less effective. In guard cell protoplasts, RL enhanced BL-dependent H+-pumping and DCMU, a photosynthetic electron transport inhibitor, eliminated this effect. RL enhanced phosphorylation levels of the H+-ATPase in response to BL, but this RL effect was not suppressed by DCMU. Furthermore, DCMU inhibited both RL-induced and BL-dependent stomatal opening in intact leaves. The photosynthetic rate in leaves correlated positively with BL-dependent stomatal opening in the presence of DCMU. We conclude that guard cell chloroplasts provide ATP and/or reducing equivalents that fuel BL-dependent stomatal opening, and that they indirectly monitor photosynthetic CO2 fixation in mesophyll chloroplasts by absorbing PAR in the epidermis.

  18. Production of guard cell protoplasts from onion and tobacco.

    Science.gov (United States)

    Zeiger, E; Hepler, P K

    1976-10-01

    Guard cell protoplasts (GCP) from young cotyledons of onion and tobacco were isolated in culture microchambers where optimal isolating and culture conditions could be determined in situ. The digestion course was quantified by following under polarized light the loss of.retardation of the birefringent cellulose of the guard cells. The assay showed that driselase has a 5-fold higher cellulytic activity than cellulysin. Driselase is, however, harmful to the GCP. Calcofluor staining was less adequate for establishing digestion courses because it increases sharply after exposing guard cells to cellulysin.Osmotic conditions were crucial for GCP survival. Onion guard cells fragment in the presence of strong plasmolyticum (>0.45 m) indicating cytoplasmic connections between neighboring guard cells and/or cytoplasmic attachments to the wall. Tobacco guard cells plasmolyzed with 0.7 m mannitol revealed several areas of strong attachment to the wall which resulted in severe damage to the cells. Healthy tobacco GCP are obtained by an initial digestion with 4% (w/v) cellulysin in 0.23 m mannitol for 2 to 3 hours followed by an increase in the osmoticum to 0.7 m to stabilize the forming protoplasts.Onion GCP were obtained by digesting paradermal slices with 4% (w/v) cellulysin in 0.23 m mannitol. Protoplasts can be osmotically released by replacing the enzyme solution with 0.23 m mannitol at early stages of digestion. They are also available after prolonged digestion (6-12 hours). Paradermal slices also yield mesophyll and epidermal cell protoplasts but they can be selectively washed away if a pure preparation of GCP is desired. Onion GCP have been kept alive in a simple culture solution for up to 10 days.

  19. Production of Guard Cell Protoplasts from Onion and Tobacco 1

    Science.gov (United States)

    Zeiger, Eduardo; Hepler, Peter K.

    1976-01-01

    Guard cell protoplasts (GCP) from young cotyledons of onion and tobacco were isolated in culture microchambers where optimal isolating and culture conditions could be determined in situ. The digestion course was quantified by following under polarized light the loss of.retardation of the birefringent cellulose of the guard cells. The assay showed that driselase has a 5-fold higher cellulytic activity than cellulysin. Driselase is, however, harmful to the GCP. Calcofluor staining was less adequate for establishing digestion courses because it increases sharply after exposing guard cells to cellulysin. Osmotic conditions were crucial for GCP survival. Onion guard cells fragment in the presence of strong plasmolyticum (>0.45 m) indicating cytoplasmic connections between neighboring guard cells and/or cytoplasmic attachments to the wall. Tobacco guard cells plasmolyzed with 0.7 m mannitol revealed several areas of strong attachment to the wall which resulted in severe damage to the cells. Healthy tobacco GCP are obtained by an initial digestion with 4% (w/v) cellulysin in 0.23 m mannitol for 2 to 3 hours followed by an increase in the osmoticum to 0.7 m to stabilize the forming protoplasts. Onion GCP were obtained by digesting paradermal slices with 4% (w/v) cellulysin in 0.23 m mannitol. Protoplasts can be osmotically released by replacing the enzyme solution with 0.23 m mannitol at early stages of digestion. They are also available after prolonged digestion (6-12 hours). Paradermal slices also yield mesophyll and epidermal cell protoplasts but they can be selectively washed away if a pure preparation of GCP is desired. Onion GCP have been kept alive in a simple culture solution for up to 10 days. Images PMID:16659703

  20. Tissue-autonomous promotion of palisade cell development by phototropin 2 in Arabidopsis.

    Science.gov (United States)

    Kozuka, Toshiaki; Kong, Sam-Geun; Doi, Michio; Shimazaki, Ken-ichiro; Nagatani, Akira

    2011-10-01

    Light is an important environmental information source that plants use to modify their growth and development. Palisade parenchyma cells in leaves develop cylindrical shapes in response to blue light; however, the photosensory mechanism for this response has not been elucidated. In this study, we analyzed the palisade cell response in phototropin-deficient mutants. First, we found that two different light-sensing mechanisms contributed to the response in different proportions depending on the light intensity. One response observed under lower intensities of blue light was mediated exclusively by a blue light photoreceptor, phototropin 2 (PHOT2). Another response was elicited under higher intensities of light in a phototropin-independent manner. To determine the tissue in which PHOT2 perceives the light stimulus to regulate the response, green fluorescent protein (GFP)-tagged PHOT2 (P2G) was expressed under the control of tissue-specific promoters in the phot1 phot2 mutant background. The results revealed that the expression of P2G in the mesophyll, but not in the epidermis, promoted palisade cell development. Furthermore, a constitutively active C-terminal kinase fragment of PHOT2 fused to GFP (P2CG) promoted the development of cylindrical palisade cells in the proper direction without the directional cue provided by light. Hence, in response to blue light, PHOT2 promotes the development of cylindrical palisade cells along a predetermined axis in a tissue-autonomous manner.

  1. Whole organ, venation and epidermal cell morphological variations are correlated in the leaves of Arabidopsis mutants.

    Science.gov (United States)

    Pérez-Pérez, José Manuel; Rubio-Díaz, Silvia; Dhondt, Stijn; Hernández-Romero, Diana; Sánchez-Soriano, Joaquín; Beemster, Gerrit T S; Ponce, María Rosa; Micol, José Luis

    2011-12-01

    Despite the large number of genes known to affect leaf shape or size, we still have a relatively poor understanding of how leaf morphology is established. For example, little is known about how cell division and cell expansion are controlled and coordinated within a growing leaf to eventually develop into a laminar organ of a definite size. To obtain a global perspective of the cellular basis of variations in leaf morphology at the organ, tissue and cell levels, we studied a collection of 111 non-allelic mutants with abnormally shaped and/or sized leaves, which broadly represent the mutational variations in Arabidopsis thaliana leaf morphology not associated with lethality. We used image-processing techniques on these mutants to quantify morphological parameters running the gamut from the palisade mesophyll and epidermal cells to the venation, whole leaf and rosette levels. We found positive correlations between epidermal cell size and leaf area, which is consistent with long-standing Avery's hypothesis that the epidermis drives leaf growth. In addition, venation parameters were positively correlated with leaf area, suggesting that leaf growth and vein patterning share some genetic controls. Positional cloning of the genes affected by the studied mutations will eventually establish functional links between genotypes, molecular functions, cellular parameters and leaf phenotypes.

  2. Carbonic anhydrases are upstream regulators of CO2-controlled stomatal movements in guard cells

    KAUST Repository

    Hu, Honghong

    2009-12-13

    The continuing rise in atmospheric CO2 causes stomatal pores in leaves to close and thus globally affects CO2 influx into plants, water use efficiency and leaf heat stress. However, the CO2-binding proteins that control this response remain unknown. Moreover, which cell type responds to CO2, mesophyll or guard cells, and whether photosynthesis mediates this response are matters of debate. We demonstrate that Arabidopsis thaliana double-mutant plants in the beta-carbonic anhydrases betaCA1 and betaCA4 show impaired CO2-regulation of stomatal movements and increased stomatal density, but retain functional abscisic-acid and blue-light responses. betaCA-mediated CO2-triggered stomatal movements are not, in first-order, linked to whole leaf photosynthesis and can function in guard cells. Furthermore, guard cell betaca-overexpressing plants exhibit instantaneous enhanced water use efficiency. Guard cell expression of mammalian alphaCAII complements the reduced sensitivity of ca1 ca4 plants, showing that carbonic anhydrase-mediated catalysis is an important mechanism for betaCA-mediated CO2-induced stomatal closure and patch clamp analyses indicate that CO2/HCO3- transfers the signal to anion channel regulation. These findings, together with ht1-2 (ref. 9) epistasis analysis demonstrate that carbonic anhydrases function early in the CO2 signalling pathway, which controls gas-exchange between plants and the atmosphere.

  3. The bulk elastic modulus and the reversible properties of cell walls in developing Quercus leaves.

    Science.gov (United States)

    Saito, Takami; Soga, Kouichi; Hoson, Takayuki; Terashima, Ichiro

    2006-06-01

    We examined the relationship between the bulk elastic modulus (epsilon) of an individual leaf obtained by the pressure-volume (P-V) technique and the mechanical properties of cell walls in the leaf. The plants used were Quercus glauca and Q. serrata, an evergreen and a deciduous broad-leaved tree species, respectively. We compared epsilon and Young's modulus of leaf specimens determined by the stretch technique at various stages of their leaf development. The results showed that epsilon increased from approximately 5 to 20 MPa during leaf development, although other potential determinants of epsilon such as the apoplastic water content in the leaf and the diameter of a palisade tissue cells remained almost constant. epsilon in these two species was similar at every developmental stages, although the apparent mechanical strength of the leaf lamina and thickness of mesophyll cell walls were greater in Q. glauca. There were significant linear relationships between Young's modulus and epsilon (P < 0.01; R (2) = 0.78 and 0.84 in Q. glauca and Q. serrata, respectively) with small y-intercepts. From these results, we conclude that epsilon is closely related to the reversible properties of the cell walls. From the estimation of epsilon based on a physical model, we suggest that the effective thickness of cell walls responsible for epsilon is smaller than the observed wall thickness.

  4. An update: improvements in imaging perfluorocarbon-mounted plant leaves with implications for studies of plant pathology, physiology, development and cell biology.

    Directory of Open Access Journals (Sweden)

    George R Littlejohn

    2014-04-01

    Full Text Available Plant leaves are optically complex, which makes them difficult to image by light microscopy. Careful sample preparation is therefore required to enable researchers to maximise the information gained from advances in fluorescent protein labelling, cell dyes and innovations in microscope technologies and techniques. We have previously shown that mounting leaves in the non-toxic, non-fluorescent perfluorocarbon (PFC, perfluorodecalin (PFD enhances the optical properties of the leaf with minimal impact on physiology. Here, we assess the use of the perfluorocarbons PFD, and perfluoroperhydrophenanthrene (PP11 for in vivo plant leaf imaging using 4 advanced modes of microscopy: laser scanning confocal microscopy (LSCM, Two-photon fluorescence (TPF microscopy, second harmonic generation (SHG microscopy and stimulated Raman scattering (SRS microscopy. For every mode of imaging tested, we observed an improved signal when leaves were mounted in PFD or in PP11, compared to mounting the samples in water. Using an image analysis technique based on autocorrelation to quantitatively assess LSCM image deterioration with depth, we show that PP11 outperformed PFD as a mounting medium by enabling the acquisition of clearer images deeper into the tissue. In addition, we show that SRS microscopy can be used to image perfluorocarbons directly in the mesophyll and thereby easily delimit the negative space within a leaf, which may have important implications for studies of leaf development. Direct comparison of on and off resonance SRS micrographs show that PFCs do not to form intracellular aggregates in live plants. We conclude that the application of PFCs as mounting media substantially increases advanced microscopy image quality of living mesophyll and leaf vascular bundle cells.

  5. Effect of Hypergravity on Localization Calcium Ions in Plant Cells Grown in Vivo and in Vitro

    Science.gov (United States)

    Nedukha, Olena

    Using plant callus tissues and Arabidopsis thaliana plants as model systems we have been investigated the effect of hypergravity on the localization and relative content of calcium ions in photosynthesizing cells. The tobacco callus cells in log stage of growth and mesophyll cells from developed A. thaliana leaves were used in the experiments. Plant samples were exposed to hypergravity at 6.5 g, 10g and 14 g for 15-60 min. After centrifugation, dye Fluo-4 was loaded in the control leaves and the centrifuged samples by the standard cytochemical method. Observation of calcium fluorescence was carried out with a laser confocal microscope LSM 5 Pascal at the excitation wave 488 nm (by the argon laser), at emission wavelength 516 nm. The data of the calcium ion distribution and quantification in cells were obtained using software "Pascal" (Carl Zeiss). The effect of hypergravity on redistribution of calcium ions in plant cells has been established. This effect is depended from exposure time and from the value of hypergravity. The cells cultivated in vitro is showed fast response to hypergravity influence. Plasmolysis cells and calcium domains formation have been observed in most of callus cells. This influence was like to that, which was wrote in Funaria hygrometrica protonema cells after 8.5 g influence (Sytnik et al., 1984). Leaf cells of A. thaliana were of less responsively to hypergravity than callus cells. Sytnik K, Kordyum E, Nedukha O. et al. 1984. Plant Cell Under Change of Geophysical Factors. Kiev: Naukova Dumka, 1-134 p.

  6. Xylogenesis in zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event.

    Science.gov (United States)

    Iakimova, Elena T; Woltering, Ernst J

    2017-04-01

    Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)-dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post-mortem. The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic zinnia (Zinnia elegans) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta. The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the

  7. 3D Plant Cell Architecture of Arabidopsis thaliana (Brassicaceae Using Focused Ion Beam–Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Bhawana

    2014-06-01

    Full Text Available Premise of the study: Focused ion beam–scanning electron microscopy (FIB-SEM combines the ability to sequentially mill the sample surface and obtain SEM images that can be used to create 3D renderings with micron-level resolution. We have applied FIB-SEM to study Arabidopsis cell architecture. The goal was to determine the efficacy of this technique in plant tissue and cellular studies and to demonstrate its usefulness in studying cell and organelle architecture and distribution. Methods: Seed aleurone, leaf mesophyll, stem cortex, root cortex, and petal lamina from Arabidopsis were fixed and embedded for electron microscopy using protocols developed for animal tissues and modified for use with plant cells. Each sample was sectioned using the FIB and imaged with SEM. These serial images were assembled to produce 3D renderings of each cell type. Results: Organelles such as nuclei and chloroplasts were easily identifiable, and other structures such as endoplasmic reticula, lipid bodies, and starch grains were distinguishable in each tissue. Discussion: The application of FIB-SEM produced 3D renderings of five plant cell types and offered unique views of their shapes and internal content. These results demonstrate the usefulness of FIB-SEM for organelle distribution and cell architecture studies.

  8. Histone deacetylation is required for progression through mitosis in tobacco cells.

    Science.gov (United States)

    Li, Yan; Butenko, Yana; Grafi, Gideon

    2005-02-01

    Post-translational modifications of core histone proteins play a key role in chromatin structure and function. Here, we study histone post-translational modifications during reentry of protoplasts derived from tobacco mesophyll cells into the cell cycle and evaluate their significance for progression through mitosis. Methylation of histone H3 at lysine residues 4 and 9 persisted in chromosomes during all phases of the cell cycle. However, acetylation of H4 and H3 was dramatically reduced during mitosis in a stage-specific manner; while deacetylation of histone H4 commenced at prophase and persisted up to telophase, histone H3 remained acetylated up to metaphase but was deacetylated at anaphase and telophase. Phosphorylation of histone H3 at serine 10 was initiated at prophase, concomitantly with deacetylation of histone H4, and persisted up to telophase. Preventing histone deacetylation by the histone deacetylase inhibitor trichostatin A (TSA) led to accumulation of protoplasts at metaphase-anaphase, and reduced S10 phosphorylation during anaphase and telophase; in cultured tobacco cells, TSA significantly reduced the frequency of mitotic figures. Our results indicate that deacetylation of histone H4 and H3 in tobacco protoplasts occurs during mitosis in a phase-specific manner, and is important for progression through mitosis.

  9. Light-enhanced dark respiration in leaves, isolated cells and protoplasts of various types of C4 plants.

    Science.gov (United States)

    Parys, Eugeniusz; Jastrzebski, Hubert

    2006-04-01

    The rate of respiratory CO2 evolution from the leaves of Zea mays, Panicum miliaceum, and Panicum maximum, representing NADP-ME, NAD-ME, and PEP-CK types of C4 plants, respectively, was increased by approximately two to four times after a period of photosynthesis. This light-enhanced dark respiration (LEDR) was a function of net photosynthetic rate specific to plant species, and was depressed by 1% O2. When malate, aspartate, oxaloacetate or glycine solution at 50 mM concentration was introduced into the leaves instead of water, the rate of LEDR was enhanced, far less in Z. mays (by 10-25%) than in P. miliaceum (by 25-35%) or P. maximum (by 40-75%). The enhancement of LEDR under glycine was relatively stable over a period of 1 h, whereas the remaining metabolites caused its decrease following a transient increase. The metabolites reduced the net photosynthesis rate in the two Panicum species, but not in Z. mays, where this process was stimulated by glycine. The bundle sheath cells from P. miliaceum exhibited a higher rate of LEDR than those of Z. mays and P. maximum. Glycine had no effect on the respiration rate of the cells, but malate increased in cells of Z. mays and P. miliaceum by about 50% and 30%, respectively. With the exception of aspartate, which stimulated both the O2 evolution and O2 uptake in P. maximum, the remaining metabolites reduced photosynthetic O2 evolution from bundle sheath cells in Panicun species. The net O2 exchange in illuminated cells of Z. mays did not respond to CO2 or metabolites. Leaf mesophyll protoplasts of Z. mays and P. miliaceum, and bundle sheath protoplasts of Z. mays, which are unable to fix CO2 photosynthetically, also produced LEDR, but the mesophyll protoplasts, compared with bundle sheath protoplasts, required twice the time of illumination to obtain the maximal rate. The results suggest that the substrates for LEDR in C4 plants are generated during a period of illumination not only via the Calvin cycle reactions, but

  10. Differences in photosynthetic responses of NADP-ME type C4 species to high light.

    Science.gov (United States)

    Romanowska, Elżbieta; Buczyńska, Alicja; Wasilewska, Wioleta; Krupnik, Tomasz; Drożak, Anna; Rogowski, Paweł; Parys, Eugeniusz; Zienkiewicz, Maksymilian

    2017-03-01

    Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m(-2) s(-1)) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m(-2) s(-1)). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H2O2 suggests that antioxidant defense is not

  11. YUCCA-mediated auxin biogenesis is required for cell fate transition occurring during de novo root organogenesis in Arabidopsis

    Science.gov (United States)

    Chen, Lyuqin; Tong, Jianhua; Xiao, Langtao; Ruan, Ying; Liu, Jingchun; Zeng, Minhuan; Huang, Hai; Wang, Jia-Wei; Xu, Lin

    2016-01-01

    Many plant organs have the ability to regenerate a new plant after detachment or wounding via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, endogenic auxin is essential for the fate transition of regeneration-competent cells to become root founder cells via activation of WUSCHEL-RELATED HOMEOBOX 11 (WOX11). However, the molecular events from leaf explant detachment to auxin-mediated cell fate transition are poorly understood. In this study, we used an assay to determine the concentration of indole-3-acetic acid (IAA) to provide direct evidence that auxin is produced after leaf explant detachment, a process that involves YUCCA (YUC)-mediated auxin biogenesis. Inhibition of YUC prevents expression of WOX11 and fate transition of competent cells, resulting in the blocking of rooting. Further analysis showed that YUC1 and YUC4 act quickly (within 4 hours) in response to wounding after detachment in both light and dark conditions and promote auxin biogenesis in both mesophyll and competent cells, whereas YUC5, YUC8, and YUC9 primarily respond in dark conditions. In addition, YUC2 and YUC6 contribute to rooting by providing a basal auxin level in the leaf. Overall, our study indicates that YUC genes exhibit a division of labour during de novo root organogenesis from leaf explants in response to multiple signals. PMID:27255928

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

    Energy Technology Data Exchange (ETDEWEB)

    Varner, J.E.

    1993-01-01

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

  13. One decade after the discovery of single-cell C4 species in terrestrial plants: what did we learn about the minimal requirements of C4 photosynthesis?

    Science.gov (United States)

    Sharpe, Richard M; Offermann, Sascha

    2014-02-01

    Until about 10 years ago the general accepted textbook knowledge was that terrestrial C4 photosynthesis requires separation of photosynthetic functions into two specialized cell types, the mesophyll and bundle sheath cells forming the distinctive Kranz anatomy typical for C4 plants. This paradigm has been broken with the discovery of Suaeda aralocaspica, a chenopod from central Asia, performing C4 photosynthesis within individual chlorenchyma cells. Since then, three more single-cell C4 (SCC4) species have been discovered in the genus Bienertia. They are interesting not only because of their unusual mode of photosynthesis but also present a puzzle for cell biologists. In these species, two morphological and biochemical specialized types of chloroplasts develop within individual chlorenchyma cells, a situation that has never been observed in plants before. Here we review recent literature concerning the biochemistry, physiology, and molecular biology of SCC4 photosynthesis. Particularly, we focus on what has been learned in relation to the following questions: How does the specialized morphology required for the operation of SCC4 develop and is there a C3 intermediate type of photosynthesis during development? What is the degree of specialization between the two chloroplast types and how does this compare to the chloroplasts of Kranz C4 species? How do nucleus-encoded proteins that are targeted to chloroplasts accumulate differentially in the two chloroplast types and how efficient is the CO2 concentrating mechanism in SCC4 species compared to the Kranz C4 forms?

  14. Directly Transforming PCR-Amplified DNA Fragments into Plant Cells Is a Versatile System That Facilitates the Transient Expression Assay

    Science.gov (United States)

    Lu, Yuming; Chen, Xi; Wu, Yuxuan; Wang, Yanping; He, Yuqing; Wu, Yan

    2013-01-01

    A circular plasmid containing a gene coding sequence has been broadly used for studying gene regulation in cells. However, to accommodate a quick screen plasmid construction and preparation can be time consuming. Here we report a PCR amplified dsDNA fragments (PCR-fragments) based transient expression system (PCR-TES) for suiting in the study of gene regulation in plant cells. Instead of transforming plasmids into plant cells, transient expression of PCR-fragments can be applicable. The transformation efficiency and expression property of PCR-fragments are comparable to transformation using plasmids. We analyzed the transformation efficiency in PCR-TES at transcription and protein levels. Our results indicate that the PCR-TES is as versatile as the conventional transformation system using plasmid DNA. Through reconstituting PYR1-mediated ABA signaling pathway in Arabidopsis mesophyll protoplasts, we were not only validating the practicality of PCR-TES but also screening potential candidates of CDPK family members which might be involved in the ABA signaling. Moreover, we determined that phosphorylation of ABF2 by CPK4 could be mediated by ABA-induced PYR1 and ABI1, demonstrating a crucial role of CDPKs in the ABA signaling. In summary, PCR-TES can be applicable to facilitate analyzing gene regulation and for the screen of putative regulatory molecules at the high throughput level in plant cells. PMID:23468926

  15. DGP1, a drought-induced guard cell-specific promoter and its function analysis in tobacco plants

    Institute of Scientific and Technical Information of China (English)

    LI; Jun; GONG; Ximing; LIN; Huiqiong; SONG; Quanbo; CHEN; J

    2005-01-01

    The genetic regulation of stomatal movement mainly depends on an efficient control system of gene expression, and guard cell-specific promoter is becoming the best choice. Here we combined the dehydration responsive element (DRE) with guard cell specific element (GCSE) to construct a novel promoter, DGP1. Histochemical assays in transgenic tobacco carryingβ-glucuronidase (gus) gene fused to DGP1 demonstrated that GUS activity was found to be highly inducible by drought treatment and specifically restricted to guard cells. No GUS activity was detected in roots, stems or flowers after treatment. Further quantitative analysis showed that GUS activity in the epidermal strips was apparently induced by dehydration and dramatically increased with the elongation of treatment. The GUS activity after 8 h treatment was 179 times that of those without treatment. Although GUS activity in roots, stems or mesophyll increased after treatment, no great changes were observed. These results suggested that DGP1 could drive target gene expressed in guard cells when plant is subjected to drought stress. And this gets us prepared to control opening and closing of stomata through plant gene engineering.

  16. Directly transforming PCR-amplified DNA fragments into plant cells is a versatile system that facilitates the transient expression assay.

    Directory of Open Access Journals (Sweden)

    Yuming Lu

    Full Text Available A circular plasmid containing a gene coding sequence has been broadly used for studying gene regulation in cells. However, to accommodate a quick screen plasmid construction and preparation can be time consuming. Here we report a PCR amplified dsDNA fragments (PCR-fragments based transient expression system (PCR-TES for suiting in the study of gene regulation in plant cells. Instead of transforming plasmids into plant cells, transient expression of PCR-fragments can be applicable. The transformation efficiency and expression property of PCR-fragments are comparable to transformation using plasmids. We analyzed the transformation efficiency in PCR-TES at transcription and protein levels. Our results indicate that the PCR-TES is as versatile as the conventional transformation system using plasmid DNA. Through reconstituting PYR1-mediated ABA signaling pathway in Arabidopsis mesophyll protoplasts, we were not only validating the practicality of PCR-TES but also screening potential candidates of CDPK family members which might be involved in the ABA signaling. Moreover, we determined that phosphorylation of ABF2 by CPK4 could be mediated by ABA-induced PYR1 and ABI1, demonstrating a crucial role of CDPKs in the ABA signaling. In summary, PCR-TES can be applicable to facilitate analyzing gene regulation and for the screen of putative regulatory molecules at the high throughput level in plant cells.

  17. The Effects of Weak Combined Magnetic Field on Cell Wall Regeneration and Frequency of Plant Protoplasts Fusion

    Science.gov (United States)

    Nedukha, Olena

    The major purpose of these experiments was to investigate plant protoplast fusion frequency and regeneration of a cell wall by protoplasts at weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The protoplasts were isolated from Nicotiana lumbaginifolia and N. silvestris leaf mesophyll and from callus tissues (Nicotiana tabacum and Glycine max). The special extra apparatus with ferromagnetic shield was used for estimate of CMF with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The fusion of protoplasts is realized by using of parent protoplasts isolated from one plant species, as well as from various plant species. Control samples were situated near the apparatus with CMF. The laser confocal microscopy was used for study of cell wall regeneration by single and fused protoplasts. The cytochemical methods with DAPI and calcofluor dye were also applied as the detectors for protoplast fusion and regeneration of cell wall. We have been established that CMF with frequency adjusted to the cyclotron frequency Mg2+ ions have shown the most positive influence on regeneration of cell wall by protoplasts. CMF adjusted to the cyclotron frequency of K+ ions very weakly affected on the frequency of protoplast fusion. Largest frequency of protoplasts fusion is noted in the CMF adjusted to the cyclotron frequency of Ca2+ in comparison with the control samples.

  18. Silicon alleviates cadmium toxicity by enhanced photosynthetic rate and modified bundle sheath's cell chloroplasts ultrastructure in maize.

    Science.gov (United States)

    Vaculík, Marek; Pavlovič, Andrej; Lux, Alexander

    2015-10-01

    Silicon was shown to alleviate the negative effects of various biotic and abiotic stresses on plant growth. Although the positive role of Si on toxic and heavy metal Cd has been already described, the mechanisms have been explained only partially and still remain unclear. In the present study we investigated the effect of Si on photosynthetic-related processes in maize exposed to two different levels of Cd via measurements of net photosynthetic rate (AN), chlorophyll a fluorescence and pigment analysis, as well as studies of leaf tissue anatomy and cell ultrastructure using bright-field and transmission electron microscopy. We found that Si actively alleviated the toxic syndromes of Cd by increasing AN, effective photochemical quantum yield of photosystem II (ϕPSII) and content of assimilation pigments, although did not decrease the concentration of Cd in leaf tissues. Cadmium did not affect the leaf anatomy and ultrastructure of leaf mesophyll's cell chloroplasts; however, Cd negatively affected thylakoid formation in chloroplasts of bundle sheath cells, and this was alleviated by Si. Improved thylakoid formation in bundle sheath's cell chloroplasts may contribute to Si-induced enhancement of photosynthesis and related increase in biomass production in C4 plant maize.

  19. AtMYB41 activates ectopic suberin synthesis and assembly in multiple plant species and cell types.

    Science.gov (United States)

    Kosma, Dylan K; Murmu, Jhadeswar; Razeq, Fakhria M; Santos, Patricia; Bourgault, Richard; Molina, Isabel; Rowland, Owen

    2014-10-01

    Suberin is a lipid and phenolic cell wall heteropolymer found in the roots and other organs of all vascular plants. Suberin plays a critical role in plant water relations and in protecting plants from biotic and abiotic stresses. Here we describe a transcription factor, AtMYB41 (At4g28110), that can activate the steps necessary for aliphatic suberin synthesis and deposition of cell wall-associated suberin-like lamellae in both Arabidopsis thaliana and Nicotiana benthamiana. Overexpression of AtMYB41 increased the abundance of suberin biosynthetic gene transcripts by orders of magnitude and resulted in the accumulation of up to 22 times more suberin-type than cutin-type aliphatic monomers in leaves. Overexpression of AtMYB41 also resulted in elevated amounts of monolignols in leaves and an increase in the accumulation of phenylpropanoid and lignin biosynthetic gene transcripts. Surprisingly, ultrastructural data indicated that overexpression led to the formation of suberin-like lamellae in both epidermal and mesophyll cells of leaves. We further implicate AtMYB41 in the production of aliphatic suberin under abiotic stress conditions. These results provide insight into the molecular-genetic mechanisms of the biosynthesis and deposition of a ubiquitous cell wall-associated plant structure and will serve as a basis for discovering the transcriptional network behind one of the most abundant lipid-based polymers in nature.

  20. Blue light-dependent nuclear positioning in Arabidopsis thaliana leaf cells.

    Science.gov (United States)

    Iwabuchi, Kosei; Sakai, Tatsuya; Takagi, Shingo

    2007-09-01

    The plant nucleus changes its intracellular position not only upon cell division and cell growth but also in response to environmental stimuli such as light. We found that the nucleus takes different intracellular positions depending on blue light in Arabidopsis thaliana leaf cells. Under dark conditions, nuclei in mesophyll cells were positioned at the center of the bottom of cells (dark position). Under blue light at 100 mumol m(-2) s(-1), in contrast, nuclei were located along the anticlinal walls (light position). The nuclear positioning from the dark position to the light position was fully induced within a few hours of blue light illumination, and it was a reversible response. The response was also observed in epidermal cells, which have no chloroplasts, suggesting that the nucleus has the potential actively to change its position without chloroplasts. Light-dependent nuclear positioning was induced specifically by blue light at >50 mumol m(-2) s(-1). Furthermore, the response to blue light was induced in phot1 but not in phot2 and phot1phot2 mutants. Unexpectedly, we also found that nuclei as well as chloroplasts in phot2 and phot1phot2 mutants took unusual intracellular positions under both dark and light conditions. The lack of the response and the unusual positioning of nuclei and chloroplasts in the phot2 mutant were recovered by externally introducing the PHOT2 gene into the mutant. These results indicate that phot2 mediates the blue light-dependent nuclear positioning and the proper positioning of nuclei and chloroplasts. This is the first characterization of light-dependent nuclear positioning in spermatophytes.

  1. Comparative cell-specific transcriptomics reveals differentiation of C4 photosynthesis pathways in switchgrass and other C4 lineages.

    Science.gov (United States)

    Rao, Xiaolan; Lu, Nan; Li, Guifen; Nakashima, Jin; Tang, Yuhong; Dixon, Richard A

    2016-03-01

    Almost all C4 plants require the co-ordination of the adjacent and fully differentiated cell types, mesophyll (M) and bundle sheath (BS). The C4 photosynthetic pathway operates through two distinct subtypes based on how malate is decarboxylated in BS cells; through NAD-malic enzyme (NAD-ME) or NADP-malic enzyme (NADP-ME). The diverse or unique cell-specific molecular features of M and BS cells from separate C4 subtypes of independent lineages remain to be determined. We here provide an M/BS cell type-specific transcriptome data set from the monocot NAD-ME subtype switchgrass (Panicum virgatum). A comparative transcriptomics approach was then applied to compare the M/BS mRNA profiles of switchgrass, monocot NADP-ME subtype C4 plants maize and Setaria viridis, and dicot NAD-ME subtype Cleome gynandra. We evaluated the convergence in the transcript abundance of core components in C4 photosynthesis and transcription factors to establish Kranz anatomy, as well as gene distribution of biological functions, in these four independent C4 lineages. We also estimated the divergence between NAD-ME and NADP-ME subtypes of C4 photosynthesis in the two cell types within C4 species, including differences in genes encoding decarboxylating enzymes, aminotransferases, and metabolite transporters, and differences in the cell-specific functional enrichment of RNA regulation and protein biogenesis/homeostasis. We suggest that C4 plants of independent lineages in both monocots and dicots underwent convergent evolution to establish C4 photosynthesis, while distinct C4 subtypes also underwent divergent processes for the optimization of M and BS cell co-ordination. The comprehensive data sets in our study provide a basis for further research on evolution of C4 species. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Further observations on cell-wall formation around isolated protoplasts of tobacco and tomato.

    Science.gov (United States)

    Willison, J H; Grout, B W

    1978-01-01

    Freeze-etch observations of protoplasts isolated from tobacco (Nicotiana tabacum L.) mesophyll tissue and tomato (Lycopersicum esculentum Mill.) fruit locule tissue are described which clarify earlier observations (Burgess, J., Fleming, E.N., Planta 131, 173-178, 1976; Planta 133, 267-273, 1977), obtained using scanning electron microscopy. of "fibres" associated with "projections" from these cell surfaces. It is demonstrated (1) that the "fibres" consist of bundles of small numbers of microfibrils which have become artifactually thickened by the deposition of coating materials, and (2) that the apparent association between "fibres" and "projections" results from microfibrils being lifted preferentially from protoplast surfaces in regions rich in "projections" (plasmalemmasomes). With the higher resolution available using freeze-etching it can be demonstrated that microfibril deposition does not occur in discontinuous zones on these protoplast surfaces. Globules associated with microfibril termini in radish (Raphanus sativus L.) roots are illustrated and it is proposed that turgor pressure differences between isolated protoplasts and intact tissue may account for the absence of similar globules from isolated protoplast surfaces.

  3. Lesion simulating disease 1 and enhanced disease susceptibility 1 differentially regulate UV-C-induced photooxidative stress signalling and programmed cell death in Arabidopsis thaliana.

    Science.gov (United States)

    Wituszyńska, Weronika; Szechyńska-Hebda, Magdalena; Sobczak, Mirosław; Rusaczonek, Anna; Kozłowska-Makulska, Anna; Witoń, Damian; Karpiński, Stanisław

    2015-02-01

    As obligate photoautotrophs, plants are inevitably exposed to ultraviolet (UV) radiation. Because of stratospheric ozone depletion, UV has become more and more dangerous to the biosphere. Therefore, it is important to understand UV perception and signal transduction in plants. In the present study, we show that lesion simulating disease 1 (LSD1) and enhanced disease susceptibility 1 (EDS1) are antagonistic regulators of UV-C-induced programmed cell death (PCD) in Arabidopsis thaliana. This regulatory dependence is manifested by a complex deregulation of photosynthesis, reactive oxygen species homeostasis, antioxidative enzyme activity and UV-responsive genes expression. We also prove that a UV-C radiation episode triggers apoptotic-like morphological changes within the mesophyll cells. Interestingly, chloroplasts are the first organelles that show features of UV-C-induced damage, which may indicate their primary role in PCD development. Moreover, we show that Arabidopsis Bax inhibitor 1 (AtBI1), which has been described as a negative regulator of plant PCD, is involved in LSD1-dependent cell death in response to UV-C. Our results imply that LSD1 and EDS1 regulate processes extinguishing excessive energy, reactive oxygen species formation and subsequent PCD in response to different stresses related to impaired electron transport.

  4. [Hydroxyproline: Rich glycoproteins of the plant and cell wall]. Annual technical progress report, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Varner, J.E.

    1993-06-01

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

  5. Altered physiology, cell structure, and gene expression of Theobroma cacao seedlings subjected to Cu toxicity.

    Science.gov (United States)

    Souza, Vânia L; de Almeida, Alex-Alan F; Souza, Jadiel de S; Mangabeira, Pedro A O; de Jesus, Raildo M; Pirovani, Carlos P; Ahnert, Dário; Baligar, Virupax C; Loguercio, Leandro L

    2014-01-01

    Seedlings of Theobroma cacao CCN 51 genotype were grown under greenhouse conditions and exposed to increasing concentrations of Cu (0.005, 1, 2, 4, 8, 16, and 32 mg Cu L(-1)) in nutrient solution. When doses were equal or higher than 8 mg Cu L(-1), after 24 h of treatment application, leaf gas exchange was highly affected and changes in chloroplasts thylakoids of leaf mesophyll cells and plasmolysis of cells from the root cortical region were observed. In addition, cell membranes of roots and leaves were damaged. In leaves, 96 h after treatments started, increases in the percentage of electrolyte leakage through membranes were observed with increases of Cu in the nutrient solution. Moreover, there was an increase in the concentration of thiobarbituric acid-reactive substances in roots due to lipid peroxidation of membranes. Chemical analysis showed that increases in Cu concentrations in vegetative organs of T. cacao increased with the increase of the metal in the nutrient solution, but there was a greater accumulation of Cu in roots than in shoots. The excess of Cu interfered in the levels of Mn, Zn, Fe, Mg, K, and Ca in different organs of T. cacao. Analysis of gene expression via RTq-PCR showed increased levels of MT2b, SODCyt, and PER-1 expression in roots and of MT2b, PSBA, PSBO, SODCyt, and SODChI in leaves. Hence, it was concluded that Cu in nutrient solution at doses equal or above 8 mg L(-1) significantly affected leaf gas exchange, cell ultrastructure, and transport of mineral nutrients in seedlings of this T. cacao genotype.

  6. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. ... the body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  7. Cells, cells, and more cells.

    Science.gov (United States)

    Bhatti, M Tariq; Gres, Katherine E; Petitto, Virginia B; Cross, Shelley Ann

    2007-01-01

    A 64-year-old woman presented with bilateral optic nerve swelling, vitreous cells, and cerebrospinal fluid monocytic pleocytosis. A chest radiograph and computed tomography demonstrated a lesion in the left lung, which histologically was confirmed to be a small-cell lung carcinoma. The serum was positive for the anti-CV2 (anti-CRMP-5) antibody. Following treatment with chemoradiation the optic nerve swelling and vitritis resolved. The differential diagnosis of uveal-meningeal diseases is discussed and the pathophysiology and clinical manifestations of paraneoplastic syndromes reviewed.

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

    Science.gov (United States)

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

    2016-05-01

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

  9. Characterization of NAC domain transcription factors implicated in control of vascular cell differentiation in Arabidopsis and Populus.

    Science.gov (United States)

    Grant, Emily H; Fujino, Takeshi; Beers, Eric P; Brunner, Amy M

    2010-07-01

    Wood has a wide variety of uses and is arguably the most important renewable raw material. The composition of xylem cell types in wood determines the utility of different types of wood for distinct commercial applications. Using expression profiling and phylogenetic analysis, we identified many xylem-associated regulatory genes that may control the differentiation of cells involved in wood formation in Arabidopsis and poplar. Prominent among these are NAC domain transcription factors (NACs). We studied NACs with putative involvement as negative (XND1 from Arabidopsis and its poplar orthologs PopNAC118, PopNAC122, PopNAC128, PopNAC129), or positive (SND2 and SND3 from Arabidopsis and their poplar orthologs PopNAC105, PopNAC154, PopNAC156, PopNAC157) regulators of secondary cell wall synthesis. Using quantitative PCR and in situ hybridization, we evaluated expression of these Populus NACs in a developmental gradient and in association with reaction wood and found that representatives from both groups were associated with wood-forming tissue and phloem fibers. Additionally, XND1 orthologs were expressed in mesophyll cells of developing leaves. We prepared transgenic Arabidopsis and poplar plants for overexpression of selected NACs. XND1 overexpression in poplar resulted in severe stunting. Additionally, poplar XND1 overexpressors lacked phloem fibers and showed reductions in cell size and number, vessel number, and frequency of rays in the xylem. Overexpression of PopNAC122, an XND1 ortholog, yielded an analogous phenotype in Arabidopsis. Overexpression of PopNAC154 in poplar reduced height growth and increased the relative proportion of bark versus xylem.

  10. Decreased photosynthesis in the erect panicle 3 (ep3) mutant of rice is associated with reduced stomatal conductance and attenuated guard cell development.

    Science.gov (United States)

    Yu, Hongyang; Murchie, Erik H; González-Carranza, Zinnia H; Pyke, Kevin A; Roberts, Jeremy A

    2015-03-01

    The ERECT PANICLE 3 gene of rice encodes a peptide that exhibits more than 50% sequence identity with the Arabidopsis F-box protein HAWAIIAN SKIRT (HWS). Ectopic expression of the Os02g15950 coding sequence, driven by the HWS (At3g61950) promoter, rescued the hws-1 flower phenotype in Arabidopsis confirming that EP3 is a functional orthologue of HWS. In addition to displaying an erect inflorescence phenotype, loss-of-function mutants of Os02g15950 exhibited a decrease in leaf photosynthetic capacity and stomatal conductance. Analysis of a range of physiological and anatomical features related to leaf photosynthesis revealed no alteration in Rubisco content and no notable changes in mesophyll size or arrangement. However, both ep3 mutant plants and transgenic lines that have a T-DNA insertion within the Os02g15950 (EP3) gene exhibit smaller stomatal guard cells compared with their wild-type controls. This anatomical characteristic may account for the observed decrease in leaf photosynthesis and provides evidence that EP3 plays a role in regulating stomatal guard cell development.

  11. Fusion and metabolism of plant cells as affected by microgravity.

    Science.gov (United States)

    Hampp, R; Hoffmann, E; Schönherr, K; Johann, P; De Filippis, L

    1997-01-01

    compensation. Samples taken for up to 7 d of exposure to microgravity showed the opposite effect. Here, the ratios of ATP/ADP and of NADH/NAD, and the pool size of Fru 2,6 bisp were decreased. We take this an an indication of metabolic relaxation, i.e. decreased metabolic turnover. As rates of protoplast regeneration and cell division were obviously similar to 1-g controls, we conclude that under conditions of microgravity regenerating tobacco mesophyll protoplasts need less metabolic energy for the same effort.

  12. Study of cell-differentiation and assembly of photosynthetic proteins during greening of etiolated Zea mays leaves using confocal fluorescence microspectroscopy at liquid-nitrogen temperature.

    Science.gov (United States)

    Shibata, Yutaka; Katoh, Wataru; Tahara, Yukari

    2013-04-01

    Fluorescence microspectroscopy observations were used to study the processes of cell differentiation and assemblies of photosynthesis proteins in Zea mays leaves under the greening process. The observations were done at 78K by setting the sample in a cryostat to avoid any undesired progress of the greening process during the measurements. The lateral and axial spatial resolutions of the system were 0.64μm and 4.4μm, respectively. The study revealed the spatial distributions of protochlorophyllide (PChld) in both the 632-nm-emitting and 655-nm-emitting forms within etiolated Zea mays leaves. The sizes of the fluorescence spots attributed to the former were larger than those of the latter, validating the assignment of the former and latter to the prothylakoid and prolamellar bodies, respectively. In vivo microspectroscopy observations of mature Zea mays leaves confirmed the different photosystem II (PS I)/photosystem I (PS II) ratio between the bundle sheath (BS) and mesophyll (MS) cells, which is specific for C4-plants. The BS cells in Zea mays leaves 1h after the initiation of the greening process tended to show fluorescence spectra at shorter wavelength side (at around 679nm) than the MS cells (at around 682nm). The 679-nm-emitting chlorophyll-a form observed mainly in the BS cells was attributed to putative precursor complexes to PS I. The BS cells under 3-h greening showed higher relative intensities of the PS I fluorescence band at around 735nm, suggesting the reduced PS II amount in the BS cells in this greening stage. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Cell-specific expression of tryptophan decarboxylase and 10-hydroxygeraniol oxidoreductase, key genes involved in camptothecin biosynthesis in Camptotheca acuminata Decne (Nyssaceae

    Directory of Open Access Journals (Sweden)

    Santamaria Anna

    2010-04-01

    Full Text Available Abstract Background Camptotheca acuminata is a major natural source of the terpenoid indole alkaloid camptothecin (CPT. At present, little is known about the cellular distribution of the biosynthesis of CPT, which would be useful knowledge for developing new strategies and technologies for improving alkaloid production. Results The pattern of CPT accumulation was compared with the expression pattern of some genes involved in CPT biosynthesis in C. acuminata [i.e., Ca-TDC1 and Ca-TDC2 (encoding for tryptophan decarboxylase and Ca-HGO (encoding for 10-hydroxygeraniol oxidoreductase]. Both CPT accumulation and gene expression were investigated in plants at different degrees of development and in plantlets subjected to drought-stress. In all organs, CPT accumulation was detected in epidermal idioblasts, in some glandular trichomes, and in groups of idioblast cells localized in parenchyma tissues. Drought-stress caused an increase in CPT accumulation and in the number of glandular trichomes containing CPT, whereas no increase in epidermal or parenchymatous idioblasts was observed. In the leaf, Ca-TDC1 expression was detected in some epidermal cells and in groups of mesophyll cells but not in glandular trichomes; in the stem, it was observed in parenchyma cells of the vascular tissue; in the root, no expression was detected. Ca-TDC2 expression was observed exclusively in leaves of plantlets subjected to drought-stress, in the same sites described for Ca-TDC1. In the leaf, Ca-HGO was detected in all chlorenchyma cells; in the stem, it was observed in the same sites described for Ca-TDC1; in the root, no expression was detected. Conclusions The finding that the sites of CPT accumulation are not consistently the same as those in which the studied genes are expressed demonstrates an organ-to-organ and cell-to-cell translocation of CPT or its precursors.

  14. Evolutionary Convergence of Cell-Specific Gene Expression in Independent Lineages of C4 Grasses1[W][OPEN

    Science.gov (United States)

    John, Christopher R.; Smith-Unna, Richard D.; Woodfield, Helen; Covshoff, Sarah; Hibberd, Julian M.

    2014-01-01

    Leaves of almost all C4 lineages separate the reactions of photosynthesis into the mesophyll (M) and bundle sheath (BS). The extent to which messenger RNA profiles of M and BS cells from independent C4 lineages resemble each other is not known. To address this, we conducted deep sequencing of RNA isolated from the M and BS of Setaria viridis and compared these data with publicly available information from maize (Zea mays). This revealed a high correlation (r = 0.89) between the relative abundance of transcripts encoding proteins of the core C4 pathway in M and BS cells in these species, indicating significant convergence in transcript accumulation in these evolutionarily independent C4 lineages. We also found that the vast majority of genes encoding proteins of the C4 cycle in S. viridis are syntenic to homologs used by maize. In both lineages, 122 and 212 homologous transcription factors were preferentially expressed in the M and BS, respectively. Sixteen shared regulators of chloroplast biogenesis were identified, 14 of which were syntenic homologs in maize and S. viridis. In sorghum (Sorghum bicolor), a third C4 grass, we found that 82% of these trans-factors were also differentially expressed in either M or BS cells. Taken together, these data provide, to our knowledge, the first quantification of convergence in transcript abundance in the M and BS cells from independent lineages of C4 grasses. Furthermore, the repeated recruitment of syntenic homologs from large gene families strongly implies that parallel evolution of both structural genes and trans-factors underpins the polyphyletic evolution of this highly complex trait in the monocotyledons. PMID:24676859

  15. Dendritic Cell

    OpenAIRE

    Sevda Söker

    2005-01-01

    Dendritic cells, a member of family of antigen presenting cells, are most effective cells in the primary immune response. Dendritic cells originated from dendron, in mean of tree in the Greek, because of their long and elaborate cytoplasmic branching processes. Dendritic cells constitute approximately 0.1 to 1 percent of the blood’s mononuclear cell. Dendritic cells are widely distributed, and specialized for antigen capture and T cell stimulation. In this article, structures and functions of...

  16. Physiological and Anatomical Response of Plant Leaf Tissue to Designated Air Pollutants.

    Science.gov (United States)

    1982-01-07

    of the spongy mesophyll . Alternatively, cells associated with intercellular air chambers immediately beneath stomata may collapse or be disrupted. This...crenalate and plasmolyzed. Cells of the spongy mesophyll 75 were also plasmolyzed. Membrane damage was prevalent in both cell types and the plasmalemma was...and more extensively than palisade or spongy parenchyma cells. Because there are no detailed cytological ultrastructural studies of HCl-fumigated plant

  17. Excess diffuse light absorption in upper mesophyll limits CO2 drawdown and depresses photosynthesis

    Science.gov (United States)

    Sun-grown and shade-grown leaves of some species absorb direct and diffuse light differently. Sun-grown leaves can photosynthesize ~10-15% less under diffuse compared to direct irradiance, while shade-grown leaves do not exhibit this sensitivity. In this study, we investigate if the spatial differen...

  18. Thermotolerant and mesophylic fungi from sugarcane bagasse and their prospection for biomass-degrading enzyme production

    Directory of Open Access Journals (Sweden)

    Bruna Silveira Lamanes dos Santos

    2015-09-01

    Full Text Available Nineteen fungi and seven yeast strains were isolated from sugarcane bagasse piles from an alcohol plant located at Brazilian Cerrado and identified up to species level on the basis of the gene sequencing of 5.8S-ITS and 26S ribosomal DNA regions. Four species were identified: Kluyveromyces marxianus, Aspergillus niger, Aspergillus sydowii and Aspergillus fumigatus, and the isolates were screened for the production of key enzymes in the saccharification of lignocellulosic material. Among them, three strains were selected as good producers of hemicellulolitic enzymes: A. niger (SBCM3, A. sydowii (SBCM7 and A. fumigatus (SBC4. The best β-xylosidase producer was A. niger SBCM3 strain. This crude enzyme presented optimal activity at pH 3.5 and 55 °C (141 U/g. For β-glucosidase and xylanase the best producer was A. fumigatus SBC4 strain, whose enzymes presented maximum activity at 60 °C and pH 3.5 (54 U/g and 4.0 (573 U/g, respectively. All these crude enzymes presented stability around pH 3.0–8.0 and up to 60 °C, which can be very useful in industrial processes that work at high temperatures and low pHs. These enzymes also exhibited moderate tolerance to ethanol and the sugars glucose and xylose. These similar characteristics among these fungal crude enzymes suggest that they can be used synergistically in cocktails in future studies of biomass conversion with potential application in several biotechnological sectors.

  19. 五种楠属植物叶片油细胞和黏液细胞的比较%Comparative Studies on Oil Cell and Mucilage Cell in the Leaves of 5 Phoebe Species

    Institute of Scientific and Technical Information of China (English)

    周存宇; 万小丽; 张建; 费永俊

    2015-01-01

    Using the method of organization transparent and paraffin section, the indices including shape, diameter and distri-bution of density and specific distribution in mesophyll of medium oil cell and mucilage cell of the leave of five species of Phoebe Nees [P.faberi (Hemsl.) Chun, P.chekiangensis C B Shang, P.bournei (Hemsl.) Yang , P.zhennan S.Lee et F N Wei, P.sheareri (Hemsl.) Gamble] were comparatively studied The results are as follows, oil cells are round in shape with their diameter ranks from 20 to 35 μm; most mucilage cells are elliptical in shape with their diameter ranks from 30 to 75μm.The difference in density of oil cells and mucilage cells between some species is significant.Observed from the cross sec-tion of leaves, oil cells and mucilage cells of the 5 species are all distributed in palisade tissue and near the upper epidermis%利用组织透明法和石蜡切片法比较研究了楠属(Phoebe Nees)5种植物竹叶楠[Phoebe faberi (Hemsl.) Chun]﹑浙江楠(P.chekiangensis C B Shang)﹑闽楠[P.bournei (Hemsl.) Yang]﹑楠木(P.zhennan S.Lee et F N Wei)和紫楠[P.sheareri (Hemsl.) Gamble]叶片中油细胞与黏液细胞的形状﹑直径﹑分布密度以及在叶肉中的具体分布.结果表明,5种楠属植物叶片中油细胞均为圆形,直径20~35μm;黏液细胞多为椭圆形,长轴直径30~75μm. 2种细胞的分布密度在某些种类之间差异显著. 从叶片横切面观察,5种植物的油细胞和黏液细胞均分布于栅栏组织,且靠近上表皮.

  20. Galvanic Cells

    Science.gov (United States)

    Young, I. G.

    1973-01-01

    Many standard physical chemistry textbooks contain ambiguities which lead to confusion about standard electrode potentials, calculating cell voltages, and writing reactions for galvanic cells. This article shows how standard electrode potentials can be used to calculate cell voltages and deduce cell reactions. (Author/RH)

  1. Galvanic Cells

    Science.gov (United States)

    Young, I. G.

    1973-01-01

    Many standard physical chemistry textbooks contain ambiguities which lead to confusion about standard electrode potentials, calculating cell voltages, and writing reactions for galvanic cells. This article shows how standard electrode potentials can be used to calculate cell voltages and deduce cell reactions. (Author/RH)

  2. Cell Biochips

    Science.gov (United States)

    Pioufle, B. Le; Picollet-D'Hahan, N.

    A cell biochip is a microsystem, equipped with electronic and microfluidic functions, designed to manipulate or analyse living cells. The first publications in this emerging area of research appeared toward the end of the 1980s. In 1989 Washizu described a biochip designed to fuse two cells by electropermeabilisation of the cytoplasmic membrane [1]. Research centers have devised a whole range of cell chip structures, for simultaneous or sequential analysis of single cells, cell groups, or cell tissues reconstituted on the chip. The cells are arranged in a square array on a parallel cell chip for parallel analysis, while they are examined and processed one by one in a microchannel in the case of a series cell chip. In contrast to these biochips for high-throughput analysis of a large number of cells, single-cell chips focus on the analysis of a single isolated cell. As in DNA microarrays, where a large number of oligonucleotides are ordered in a matrix array, parallel cell chips order living cells in a similar way. At each point of the array, the cells can be isolated, provided that the cell type allows this, e.g., blood cells, or cultivated in groups (most adhesion cells can only survive in groups). The aim is to allow massively parallel analysis or processing. Le Pioufle et al. describe a microdevice for the culture of single cells or small groups of cells in a micropit array [2]. Each pit is equipped to stimulate the cell or group of cells either electrically or fluidically. Among the applications envisaged are gene transfer, cell sorting, and screening in pharmacology. A complementary approach, combining the DNA microarray and cell biochip ideas, has been put forward by Bailey et al. [3]. Genes previously arrayed on the chip transfect the cultured cells on the substrate depending on their position in the array (see Fig. 19.1). This way of achieving differential lipofection on a chip was then taken up again by Yoshikawa et al. [4] with primary cells, more

  3. Reference: 5 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available al contributor to the K+ permeability. However, in the mesophyll cells of leaves, AKT2 accounted for approxi...mately 50% of the K+ permeability, whereas AKT1 unexpectedly accounted for the remainder. The approximately

  4. The cyclic nucleotide gated cation channel AtCNGC10 traffics from the ER via Golgi vesicles to the plasma membrane of Arabidopsis root and leaf cells

    Directory of Open Access Journals (Sweden)

    Andres Marilou A

    2007-09-01

    Full Text Available Abstract Background The cyclic nucleotide-gated ion channels (CNGCs maintain cation homeostasis essential for a wide range of physiological processes in plant cells. However, the precise subcellular locations and trafficking of these membrane proteins are poorly understood. This is further complicated by a general deficiency of information about targeting pathways of membrane proteins in plants. To investigate CNGC trafficking and localization, we have measured Atcngc5 and Atcngc10 expression in roots and leaves, analyzed AtCNGC10-GFP fusions transiently expressed in protoplasts, and conducted immunofluorescence labeling of protoplasts and immunoelectron microscopic analysis of high pressure frozen leaves and roots. Results AtCNGC10 mRNA and protein levels were 2.5-fold higher in roots than leaves, while AtCNGC5 mRNA and protein levels were nearly equal in these tissues. The AtCNGC10-EGFP fusion was targeted to the plasma membrane in leaf protoplasts, and lightly labeled several intracellular structures. Immunofluorescence microscopy with affinity purified CNGC-specific antisera indicated that AtCNGC5 and AtCNGC10 are present in the plasma membrane of protoplasts. Immunoelectron microscopy demonstrated that AtCNGC10 was associated with the plasma membrane of mesophyll, palisade parenchyma and epidermal cells of leaves, and the meristem, columella and cap cells of roots. AtCNCG10 was also observed in the endoplasmic reticulum and Golgi cisternae and vesicles of 50–150 nm in size. Patch clamp assays of an AtCNGC10-GFP fusion expressed in HEK293 cells measured significant cation currents. Conclusion AtCNGC5 and AtCNGC10 are plasma membrane proteins. We postulate that AtCNGC10 traffics from the endoplasmic reticulum via the Golgi apparatus and associated vesicles to the plasma membrane. The presence of the cation channel, AtCNGC10, in root cap meristem cells, cell plate, and gravity-sensing columella cells, combined with the previously reported

  5. Engineering cell-cell signaling.

    Science.gov (United States)

    Blagovic, Katarina; Gong, Emily S; Milano, Daniel F; Natividad, Robert J; Asthagiri, Anand R

    2013-10-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling on the basis of quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilize synthetic cells, advanced 'chassis' and predictive modeling to engineer the form and function of living tissues.

  6. Stem cells in cell transplantation.

    Science.gov (United States)

    Sanmartin, Agneta; English, Denis; Sanberg, Paul R

    2006-12-01

    This commentary documents the increased number of stem cell-related research reports recently published in the cell transplantation field in the journal Cell Transplantation. The journal covers a wide range of issues in cell-based therapy and regenerative medicine and is attracting clinical and preclinical articles from around the world. It thereby complements and extends the basic coverage of stem cell physiology reported in Stem Cells and Development. Sections in Cell Transplantation cover neuroscience, diabetes, hepatocytes, bone, muscle, cartilage, skin, vessels, and other tissues, as well as tissue engineering that employs novel methods with stem cells. Clearly, the continued use of biomedical engineering will depend heavily on stem cells, and these two journals are well positioned to provide comprehensive coverage of these developments.

  7. Engineering Cell-Cell Signaling

    Science.gov (United States)

    Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R.

    2014-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling based on quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilizing synthetic cells, advanced ‘chassis’ and predictive modeling to engineer the form and function of living tissues. PMID:23856592

  8. Cell Motility

    CERN Document Server

    Lenz, Peter

    2008-01-01

    Cell motility is a fascinating example of cell behavior which is fundamentally important to a number of biological and pathological processes. It is based on a complex self-organized mechano-chemical machine consisting of cytoskeletal filaments and molecular motors. In general, the cytoskeleton is responsible for the movement of the entire cell and for movements within the cell. The main challenge in the field of cell motility is to develop a complete physical description on how and why cells move. For this purpose new ways of modeling the properties of biological cells have to be found. This long term goal can only be achieved if new experimental techniques are developed to extract physical information from these living systems and if theoretical models are found which bridge the gap between molecular and mesoscopic length scales. Cell Motility gives an authoritative overview of the fundamental biological facts, theoretical models, and current experimental developments in this fascinating area.

  9. Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2012-04-01

    Full Text Available The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.Article in Lithuanian

  10. Engineering Cell-Cell Signaling

    OpenAIRE

    Blagovic, Katarina; Gong, Emily S.; Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R

    2013-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cel...

  11. Stem Cells

    Directory of Open Access Journals (Sweden)

    Madhukar Thakur

    2015-02-01

    Full Text Available Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in the body. Often called as Magic Seeds, stem cells are produced in bone marrow and circulate in blood, albeit at a relatively low concentration. These virtues together with the ability of stem cells to grow in tissue culture have paved the way for their applications to generate new and healthy tissues and to replace diseased or injured human organs. Although possibilities of stem cell applications are many, much remains yet to be understood of these remarkable magic seeds. Conclusion: This presentation shall briefly cover the origin of stem cells, the pros and cons of their growth and division, their potential application, and shall outline some examples of the contributions of radiolabeled stem cells, in this rapidly growing branch of biomedical science

  12. Types of Stem Cells

    Science.gov (United States)

    ... Stem Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... Learn About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

  13. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  14. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  15. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    '. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...... and tantalizing than stem cells, in research, in medicine, or as products....

  16. Stem cells.

    Science.gov (United States)

    Redi, Carlo Alberto; Monti, Manuela; Merico, Valeria; Neri, Tui; Zanoni, Mario; Zuccotti, Maurizio; Garagna, Silvia

    2007-01-01

    The application of stem cells to regenerative medicine is one of the actual hot topics in biomedicine. This research could help the cure of a number of diseases that are affecting a large share of the population. Some good results in cell replacement have already been obtained (infarcted heart, diabetes, Parkinson disease), apart from those of more traditional applications like severe burns and blood tumors. We are now facing crucial questions in stem cell biology. One of the key questions is how a cell begins to proliferate or differentiate. Genome reprogramming, both following nuclear transfer and cytoplast action, will likely highlight some of the molecular mechanisms of cell differentiation and dedifferentiation. In turn, these clues should be useful to the production of populations of reprogrammed cells that could develop into tissues or, in the future, into proper organs. We will overview what stem cells are, what roles they play in normal developmental processes and how stem cells could have the potential to treat diseases.

  17. Host cells and cell banking.

    Science.gov (United States)

    Stacey, Glyn N; Merten, Otto-Wilhelm

    2011-01-01

    Gene therapy based on the use of viral vectors is entirely dependent on the use of animal cell lines, mainly of mammalian origin, but also of insect origin. As for any biotechnology product for clinical use, viral -vectors have to be produced with cells derived from an extensively characterized cell bank to maintain the appropriate standard for assuring the lowest risk for the patients to be treated. Although many different cell types and lines have been used for the production of viral vectors, HEK293 cells or their derivatives have been extensively used for production of different vector types: adenovirus, oncorectrovirus, lentivirus, and AAV vectors, because of their easy handling and the possibility to grow them adherently in serum-containing medium as well as in suspension in serum-free culture medium. Despite this, these cells are not necessarily the best for the production of a given viral vector, and there are many other cell lines with significant advantages including superior growth and/or production characteristics, which have been tested and also used for the production of clinical vector batches. This chapter presents basic -considerations concerning the characterization of cell banks, in the first part, and, in the second part, practically all cell lines (at least when public information was available) established and developed for the production of the most important viral vectors (adenoviral, oncoretroviral, lentiviral, AAV, baculovirus).

  18. Sickle cell anemia

    Science.gov (United States)

    ... Anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease Images Red blood cells, sickle cell Red blood cells, normal Red blood ... multiple sickle cells Red blood cells, sickle cells Red blood cells, sickle and ... Heeney MM, Ware RE. Sickle cell disease. In: Orkin SH, Fisher DE, Ginsburg D, Look ...

  19. Cell, cell, cell: fuel cell applications moving ahead

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.

    2001-11-01

    Developments in fuel cell technology within the last decade, such as the targeting by major automakers of non-polluting fuel cells as an alternative to the internal combustion engine, are reviewed. For example, Ballard Power Systems of Vancouver is the exclusive supplier to both DaimlerCrysler and the Ford Motor Company of the fuel cell stacks that produce the power in fuel cell systems. Ballard plans the commercial launch of transit bus engines in 2002 and automotive products between 2003 and 2005. The company also sees huge opportunities for fuel cells in stationary and portable power applications. At the same time, the Calgary-based fuel cell division of Energy Ventures Inc. is developing a direct methanol fuel cell that eliminates the intermediate step of 'reforming' methanol into hydrogen that is required in the Ballard process. Energy Ventures targets small niche markets such as small utility vehicles for its direct methanol fuel cell. A completely self-contained fuel cell of this type is expected to be ready in 2002. Solid oxide fuel cells for off-grid remote power units as well as for home heat and power is yet another field of development that will be particularly attractive to operations in remote areas where reliable grid electricity is expensive and hard to obtain. A prototype 2.3 kW residential power system using natural gas was made available by Global Thermoelectric Inc in June 2001; field testing is planned for 2002, with commercial production in late 2003 or 2004. The Calgary-based Snow Leopard Resources Inc plans to use pure hydrogen sulphide obtained from sour natural gas as a hydrogen source. The prime focus of Snow Leopard is on gas plants looking for ways to increase their efficiency, obtain carbon dioxide credits and generate electricity on site. This type of fuel cell also could be of interest to companies with shut-in sour gas since these companies could use the stationary fuel cell system to generate electricity.

  20. Bi-Cell Unit for Fuel Cell.

    Science.gov (United States)

    The patent concerns a bi-cell unit for a fuel cell . The bi-cell unit is comprised of two electrode packs. Each of the electrode packs includes an...invention relates in general to a bi-cell unit for a fuel cell and in particular, to a bi-cell unit for a hydrazine-air fuel cell .

  1. Learn About Stem Cells

    Science.gov (United States)

    ... Patient Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... original cell’s DNA, cytoplasm and cell membrane. About stem cells Stem cells are the foundation of development in ...

  2. Fuel cells

    Directory of Open Access Journals (Sweden)

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  3. T Cells

    Science.gov (United States)

    ... Informed d Corporate Support Corporate Partners National Teams Partnership Opportunities d Personal Stories Ambassadors & Familiar Faces Life ... d Our Healthcare Voice Home What Is MS? Definition of MS T Cells Share this page Facebook ...

  4. Dry cell battery poisoning

    Science.gov (United States)

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  5. Electrochemical cell

    Science.gov (United States)

    Nagy, Zoltan; Yonco, Robert M.; You, Hoydoo; Melendres, Carlos A.

    1992-01-01

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90.degree. in either direction while maintaining the working and counter electrodes submerged in the electrolyte.

  6. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil and nucl......A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  7. CellTracks cell analysis system for rare cell detection

    NARCIS (Netherlands)

    Kagan, Michael T.; Trainer, Michael N.; Bendele, Teresa; Rao, Chandra; Horton, Allen; Tibbe, Arjan G.; Greve, Jan; Terstappen, Leon W.M.M.

    2002-01-01

    The CellTracks system is a Compact Disk-based cell analyzer that, similar to flow cytometry, differentiates cells that are aligned while passing through focused laser beams. In CellTracks, only immuno-magnetically labeled cells are aligned and remain in position for further analysis. This feature is

  8. Tuning Collective Cell Migration by Cell-Cell Junction Regulation

    NARCIS (Netherlands)

    Friedl, P.; Mayor, R.

    2017-01-01

    Collective cell migration critically depends on cell-cell interactions coupled to a dynamic actin cytoskeleton. Important cell-cell adhesion receptor systems implicated in controlling collective movements include cadherins, immunoglobulin superfamily members (L1CAM, NCAM, ALCAM), Ephrin/Eph receptor

  9. Tuning Collective Cell Migration by Cell-Cell Junction Regulation

    NARCIS (Netherlands)

    Friedl, P.; Mayor, R.

    2017-01-01

    Collective cell migration critically depends on cell-cell interactions coupled to a dynamic actin cytoskeleton. Important cell-cell adhesion receptor systems implicated in controlling collective movements include cadherins, immunoglobulin superfamily members (L1CAM, NCAM, ALCAM), Ephrin/Eph

  10. Formation kinetics and H2O2 distribution in chloroplasts and protoplasts of photosynthetic leaf cells of higher plants under illumination.

    Science.gov (United States)

    Naydov, I A; Mubarakshina, M M; Ivanov, B N

    2012-02-01

    The dye H(2)DCF-DA, which forms the fluorescent molecule DCF in the reaction with hydrogen peroxide, H(2)O(2), was used to study light-induced H(2)O(2) production in isolated intact chloroplasts and in protoplasts of mesophyll cells of Arabidopsis, pea, and maize. A technique to follow the kinetics of light-induced H(2)O(2) production in the photosynthesizing cells using this dye has been developed. Distribution of DCF fluorescence in these cells in the light has been investigated. It was found that for the first minutes of illumination the intensity of DCF fluorescence increases linearly after a small lag both in isolated chloroplasts and in chloroplasts inside protoplast. In protoplasts of Arabidopsis mutant vtc2-2 with disturbed biosynthesis of ascorbate, the rate of increase in DCF fluorescence intensity in chloroplasts was considerably higher than in protoplasts of the wild type plant. Illumination of protoplasts also led to an increase in DCF fluorescence intensity in mitochondria. Intensity of DCF fluorescence in chloroplasts increased much more rapidly than in cytoplasm. The cessation of cytoplasmic movement under illumination lowered the rate of DCF fluorescence intensity increase in chloroplasts and sharply accelerated it in the cytoplasm. It was revealed that in response to switching off the light, the intensity of fluorescence of both DCF and fluorescent dye FDA increases in the cytoplasm in the vicinity of chloroplasts, while it decreases in the chloroplasts; the opposite changes occur in response to switching on the light again. It was established that these phenomena are connected with proton transport from chloroplasts in the light. In the presence of nigericin, which prevents the establishment of transmembrane proton gradients, the level of DCF fluorescence in cytoplasm was higher and increased more rapidly than in the chloroplasts from the very beginning of illumination. These results imply the presence of H(2)O(2) export from chloroplasts to

  11. Sickle Cell Anemia

    Science.gov (United States)

    Sickle cell anemia is a disease in which your body produces abnormally shaped red blood cells. The cells are shaped like ... normal, round red blood cells. This leads to anemia. The sickle cells also get stuck in blood ...

  12. Sickle Cell Disease

    Science.gov (United States)

    ... sickle cell disease?Sickle cell disease, also called sickle cell anemia, is a hereditary condition (which means it runs ... disease, hemoglobin SS disease, hemoglobin synthesis, hemoglobinopathies, ... cell anemia, sickle cell crisis, vaso-occlusive crisis Family Health, ...

  13. Comparison of essential and non-essential element distribution in leaves of the Cd/Zn hyperaccumulator Thlaspi praecox as revealed by micro-PIXE.

    Science.gov (United States)

    Vogel-Mikus, Katarina; Simcic, Jure; Pelicon, Primoz; Budnar, Milos; Kump, Peter; Necemer, Marijan; Mesjasz-Przybyłowicz, Jolanta; Przybyłowicz, Wojciech J; Regvar, Marjana

    2008-10-01

    A detailed localization of elements in leaf tissues of the field-collected Cd/Zn hyperaccumulator Thlaspi praecox (Brassicaceae) growing at a highly metal-polluted site was determined by micro-proton-induced X-ray emission (micro-PIXE) in order to reveal and compare nutrient and non-essential element accumulation patterns in the case of multiple metal accumulation within particular leaf tissues, including the detailed distribution between apoplast and symplast regions. On the larger scans, the highest concentrations of metals were observed in the epidermis, S and Ca in the palisade mesophyll, Cl in the spongy mesophyll and vascular bundles, and P and K in the vascular bundles. On the more detailed scans, the highest Cd, Pb, Cl and K concentrations were observed in vascular bundle collenchyma. The relative element distribution (%) was calculated based on concentrations of elements in particular leaf tissues and their relative weight portions, indicating that most of the accumulated Zn was located in epidermises, while the majority of Cd and Pb was distributed within the mesophyll. Detailed scans of epidermal/mesophyll tissues revealed that Zn was mainly accumulated and detoxified in the symplast of large vacuolated epidermal cells, Cd in the mesophyll symplast, and Pb in the mesophyll symplast and apoplast.

  14. Potent Cells

    Science.gov (United States)

    Liu, Dennis

    2007-01-01

    It seems hard to believe that Dolly the cloned sheep was born 10 years ago, kindling furious arguments over the prospects and ethics of cloning a human. Today, the controversy over cloning is entwined, often confused, with concerns over the use of human embryonic stem cells. Most people are unclear what cloning is, and they know even less when it…

  15. Potent Cells

    Science.gov (United States)

    Liu, Dennis

    2007-01-01

    It seems hard to believe that Dolly the cloned sheep was born 10 years ago, kindling furious arguments over the prospects and ethics of cloning a human. Today, the controversy over cloning is entwined, often confused, with concerns over the use of human embryonic stem cells. Most people are unclear what cloning is, and they know even less when it…

  16. Electrochemical Cell

    DEFF Research Database (Denmark)

    1999-01-01

    The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0

  17. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  18. [Eco-anatomical characteristics of Sophora davidii leaves along an elevation gradient in upper Minjiang River dry valley].

    Science.gov (United States)

    Li, Fanglan; Bao, Weikai; Liu, Junhua; Wu, Ning

    2006-01-01

    This paper studied the eco-anatomical characteristics of Sorphora davidii leaves at the elevations of 1,650, 1,750, 1,850 and 1,950 m in the upper reaches of Minjiang River dry valley. The indices investigated were leaf length (LL), leaf width (LW), LL/ LW, leaf area, leaf thickness, leaf epidermal thickness, leaf palisade mesophyll thickness (P), leaf spongy mesophyll thickness (S), P/S, leaf cutin membrane thickness, leaf stomatal density and area, leaf epidermis cell density and area, and leaf pubescence length and density. The results showed that the leaves of S. davidii were elliptic, with an area 0.144 approximately 0.208 cm2 and a thickness 171.58 approximately 195.83 microm. The mesophyll was significantly differentiated into palisade and spongy. The thickness of palisade mesophyll was 69.83 approximately 82.42 microm, that of spongy mesophyll was 62.00 approximately 80.67 microm, and P/S was 1.14 approximately 1.01. Upper epidermal thickness was 14.03 approximately 15.33 microm, while lower epidermal thickness was 13.88 approximately 16.17 microm. The stomatal density, stomatal area, epidermis cell density, epidermis cell area, pubescence length, and pubescence density were 13.71 approximately 15.02 mm(-2), 249.86 approximately 280.43 microm2, 160.54 approximately 178.43 mm(-2), 557.43 approximately 626.85 microm2, 186.51 approximately 260.99 microm, and 18.29 approximately 32.27 mm(-2), respectively. With increasing elevation, the leaf area, leaf thickness, palisade mesophyll thickness, spongy mesophyll thickness, stomatal area, epidermis cell area and pubescence density were increased, while cutin membrane thickness, epidermis cell density, pubescence length, and stomatal density were decreased. There was no significant difference in LL/LW, P/S, epidermal thickness and stomatal density along the elevation gradient.

  19. Calcium Distribution in Globoid Crystals of Cucurbita Cotyledon Protein Bodies 1

    Science.gov (United States)

    Lott, John N. A.; Spitzer, Ernest; Vollmer, Catherine M.

    1979-01-01

    Energy-dispersive x-ray analysis was used to investigate the location of globoid crystals with relatively high Ca levels within cotyledons of Cucurbita maxima, Cucurbita mixta, and Cucurbita andreana. The small globoid crystals in both upper and lower epidermal cells commonly contained Ca. Ca was present in globoid crystals of all provascular regions with the exception of the very small provascular regions of C. maxima. In C. maxima and C. mixta cotyledons, some cases were observed where Ca was found in the globoid crystals of the first layer of mesophyll cells surrounding the provascular region, but in general Ca was absent from globoid crystals of palisade and spongy mesophyll cells. In C. andreana, globoid crystals of palisade and spongy mesophyll cells commonly contained at least some Ca. Cell position and cell type are factors affecting the Ca content of globoid crystals in protein bodies. PMID:16660825

  20. Benzophenone Synthase and Chalcone Synthase Accumulate in the Mesophyll of Hypericum perforatum Leaves at Different Developmental Stages

    OpenAIRE

    Belkheir, Asma K.; Gaid, Mariam; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2016-01-01

    The active medicinal constituents in Hypericum perforatum, used to treat depression and skin irritation, include flavonoids and xanthones. The carbon skeletons of these compounds are formed by chalcone synthase (CHS) and benzophenone synthase (BPS), respectively. Polyclonal antisera were raised against the polyketide synthases from Hypericum androsaemum and their IgG fractions were isolated. Immunoblotting and immunotitration were used to test the IgGs for crossreactivity and monospecificity ...

  1. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  2. Ghost cell lesions

    Directory of Open Access Journals (Sweden)

    E Rajesh

    2015-01-01

    Full Text Available Ghost cells have been a controversy for a long time. Ghost cell is a swollen/enlarged epithelial cell with eosnophilic cytoplasm, but without a nucleus. In routine H and E staining these cells give a shadowy appearance. Hence these cells are also called as shadow cells or translucent cells. The appearance of these cells varies from lesion to lesion involving odontogenic and nonodontogenic lesions. This article review about the origin, nature and significance of ghost cells in different neoplasms.

  3. The role of cell wall-based defences in the early restriction of non-pathogenic hrp mutant bacteria in Arabidopsis.

    Science.gov (United States)

    Mitchell, Kathy; Brown, Ian; Knox, Paul; Mansfield, John

    2015-04-01

    We have investigated the cause of the restricted multiplication of hrp mutant bacteria in leaves of Arabidopsis. Our focus was on early interactions leading to differentiation between virulent wild-type and non-pathogenic hrpA mutant strains of Pseudomonas syringae pv. tomato. An initial drop in recoverable bacteria detected 0-4 h after inoculation with either strain was dependent on a functional FLS2 receptor and H2O2 accumulation in challenged leaves. Wild-type bacteria subsequently multiplied rapidly whereas the hrpA mutant was restricted within 6 h. Despite the early restriction, the hrpA mutant was still viable several days after inoculation. Analysis of intercellular washing fluids (IWFs), showed that high levels of nutrients were readily available to bacteria in the apoplast and that no diffusible inhibitors were produced in response to bacterial challenge. Histochemical and immunocytochemical methods were used to detect changes in polysaccharides (callose, two forms of cellulose, and pectin), arabinogalactan proteins (AGPs), H2O2 and peroxidase. Quantitative analysis showed very similar changes in localisation of AGPs, cellulose epitopes and callose 2 and 4 h after inoculation with either strain. However from 6 to 12 h after inoculation papillae expanded only next to the hrp mutant. In contrast to the similar patterns of secretory activity recorded from mesophyll cells, accumulation of H2O2 and peroxidase was significantly greater around the hrpA mutant within the first 4h after inoculation. A striking differential accumulation of H2O2 was also found in chloroplasts in cells next to the mutant. Ascorbate levels were lower in the IWFs recovered from sites inoculated with the hrp mutant than with wild-type bacteria. The critical response, observed at the right time and place to explain the observed differential behaviour of wild-type and hrpA mutant bacteria was the accumulation of H2O2, probably generated through Type III peroxidase activity and in

  4. [Inflammatory dendritic cells].

    Science.gov (United States)

    Segura, Elodie; Amigorena, Sebastian

    2014-01-01

    Dendritic cells are a rare and heterogeneous population of professional antigen-presenting cells. Several murine dendritic cell subpopulations have been identified that differ in their phenotype and functional properties. In the steady state, committed dendritic cell precursors differentiate into lymphoid organ-resident dendritic cells and migratory tissue dendritic cells. During inflammation appears an additional dendritic cell subpopulation that has been termed « inflammatory dendritic cells ». Inflammatory dendritic cells differentiate in situ from monocytes recruited to the site of inflammation. Here, we discuss how mouse inflammatory dendritic cells differ from macrophages and from other dendritic cell populations. Finally, we review recent work on human inflammatory dendritic cells.

  5. Red blood cells, sickle cell (image)

    Science.gov (United States)

    Sickle cell anemia is an inherited blood disease in which the red blood cells produce abnormal pigment (hemoglobin). ... abnormal hemoglobin causes deformity of the red blood cells into crescent or sickle-shapes, as seen in this photomicrograph.

  6. Red blood cells, multiple sickle cells (image)

    Science.gov (United States)

    Sickle cell anemia is an inherited disorder in which abnormal hemoglobin (the red pigment inside red blood cells) is produced. The abnormal hemoglobin causes red blood cells to assume a sickle shape, like the ones seen in this photomicrograph.

  7. Structural assessment of the impact of environmental constraints on Arabidopsis thaliana leaf growth: a 3D approach.

    Science.gov (United States)

    Wuyts, Nathalie; Massonnet, Catherine; Dauzat, Myriam; Granier, Christine

    2012-09-01

    Light and soil water content affect leaf surface area expansion through modifications in epidermal cell numbers and area, while effects on leaf thickness and mesophyll cell volumes are far less documented. Here, three-dimensional imaging was applied in a study of Arabidopsis thaliana leaf growth to determine leaf thickness and the cellular organization of mesophyll tissues under moderate soil water deficit and two cumulative light conditions. In contrast to surface area, thickness was highly conserved in response to water deficit under both low and high cumulative light regimes. Unlike epidermal and palisade mesophyll tissues, no reductions in cell number were observed in the spongy mesophyll; cells had rather changed in volume and shape. Furthermore, leaf features of a selection of genotypes affected in leaf functioning were analysed. The low-starch mutant pgm had very thick leaves because of unusually large palisade mesophyll cells, together with high levels of photosynthesis and stomatal conductance. By means of an open stomata mutant and a 9-cis-epoxycarotenoid dioxygenase overexpressor, it was shown that stomatal conductance does not necessarily have a major impact on leaf dimensions and cellular organization, pointing to additional mechanisms for the control of CO(2) diffusion under high and low stomatal conductance, respectively.

  8. CellFinder: a cell data repository

    OpenAIRE

    Stachelscheid, H.; Seltmann, S.; Lekschas, F.; Fontaine, J.F.; Mah, N.; Neves, M.; Andrade-Navarro, M.A.; Leser, U; Kurtz, A.

    2014-01-01

    CellFinder (http://www.cellfinder.org) is a comprehensive one-stop resource for molecular data characterizing mammalian cells in different tissues and in different development stages. It is built from carefully selected data sets stemming from other curated databases and the biomedical literature. To date, CellFinder describes 3394 cell types and 50 951 cell lines. The database currently contains 3055 microscopic and anatomical images, 205 whole-genome expression profiles of 194 cell/tissue t...

  9. Molluscan cells in culture: primary cell cultures and cell lines

    OpenAIRE

    2013-01-01

    In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as bi...

  10. Electrorefining cell evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, M.C.; Thomas, R.L. (ed.)

    1989-04-14

    Operational characteristics of the LANL electrorefining cell, a modified LANL electrorefining cell, and an advanced electrorefining cell (known as the CRAC cell) were determined. Average process yields achieved were: 75% for the LANL cell, 82% for the modified LANL cell, and 86% for the CRAC cell. All product metal from the LANL and modified LANL cells was within foundry specifications. Metal from one run in the CRAC cell exceeded foundry specifications for tantalum. The LANL and modified LANL cells were simple in design and operation, but product separation was more labor intensive than with the CRAC cell. The CRAC cell was more complicated in design but remained relatively simple in operation. A decision analysis concluded that the modified LANL cell was the preferred cell. It was recommended that the modified LANL cell be implemented by the Plutonium Recovery Project at Rocky Flats and that development of the CRAC cell continue. 8 refs., 22 figs., 12 tabs.

  11. Antiparietal cell antibody test

    Science.gov (United States)

    APCA; Anti-gastric parietal cell antibody; Atrophic gastritis - anti-gastric parietal cell antibody; Gastric ulcer - anti-gastric parietal cell antibody; Pernicious anemia - anti-gastric parietal cell antibody; ...

  12. Sickle cell test

    Science.gov (United States)

    ... abnormal hemoglobin that causes sickle cell disease and sickle cell trait. Hemoglobin is a protein in red blood cells ... has two abnormal hemoglobin S genes. A person with sickle cell trait has only one of these abnormal genes and ...

  13. 不同秸秆水提液在不同光照强度下对马唐萌发与生长的影响%The Effects of Water Extracts from Different Straws on Seed Germination and Growth of Crabgrass (Digitaria sanguinalis) Under Different Light Intensities

    Institute of Scientific and Technical Information of China (English)

    杨彩宏; 田兴山; 冯莉; 张泰劼; 高家东; 岳茂峰; 崔烨

    2014-01-01

    为了明确不同秸秆水提液在不同光照强度下对马唐种子萌发与生长的影响.本研究采用室内种子培养皿法测定了水稻、甜玉米、香蕉假茎以及甘蔗秸秆水浸提液在3种光照强度下对马唐种子发芽率、胚根、胚芽生长的影响.结果显示,(1)与800 lx、4000 lx光照强度下对照马唐种子的萌发率相比(>90%),完全黑暗条件能够抑制对照马唐种子的萌发,但萌发率仍>70%;(2)3种光照强度下,与对照相比,不同秸秆水提液均对马唐种子发芽率有抑制作用,水提液浓度越高,发芽率越低,且完全黑暗条件下抑制作用更显著,而对胚芽和胚根生长影响不大;(3)4种秸秆水提液在3种光照强度下对马唐种子发芽率的抑制作用顺序均为稻秆>甘蔗>香蕉假茎>甜玉米.

  14. Molluscan cells in culture: primary cell cultures and cell lines.

    Science.gov (United States)

    Yoshino, T P; Bickham, U; Bayne, C J

    2013-06-01

    In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as biomonitors for environmental contaminants, as models for gene transfer technologies, and for studies of innate immunity and neoplastic disease. Despite efforts to isolate proliferative cell lines from molluscs, the snail Biomphalaria glabrata Say, 1818 embryonic (Bge) cell line is the only existing cell line originating from any molluscan species. Taking an organ systems approach, this review summarizes efforts to establish molluscan cell cultures and describes the varied applications of primary cell cultures in research. Because of the unique status of the Bge cell line, an account is presented of the establishment of this cell line, and of how these cells have contributed to our understanding of snail host-parasite interactions. Finally, we detail the difficulties commonly encountered in efforts to establish cell lines from molluscs and discuss how these difficulties might be overcome.

  15. DNA-cell conjugates

    Science.gov (United States)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  16. Optimizing cell viability in dropletbased cell deposition

    NARCIS (Netherlands)

    Hendriks, Jan; Visser, C.W.; Henke, S.J.; Leijten, Jeroen Christianus Hermanus; Saris, Daniël B.F.; Sun, Chao; Lohse, Detlef; Karperien, Hermanus Bernardus Johannes

    2015-01-01

    Biofabrication commonly involves the use of liquid droplets to transport cells to the printed structure. However, the viability of the cells after impact is poorly controlled and understood, hampering applications including cell spraying, inkjet bioprinting, and laser-assisted cell transfer. Here,

  17. Skin Stem Cells in Skin Cell Therapy

    Directory of Open Access Journals (Sweden)

    Mollapour Sisakht

    2015-12-01

    Full Text Available Context Preclinical and clinical research has shown that stem cell therapy is a promising therapeutic option for many diseases. This article describes skin stem cells sources and their therapeutic applications. Evidence Acquisition Compared with conventional methods, cell therapy reduces the surgical burden for patients because it is simple and less time-consuming. Skin cell therapy has been developed for variety of diseases. By isolation of the skin stem cell from the niche, in vitro expansion and transplantation of cells offers a surprising healing capacity profile. Results Stem cells located in skin cells have shown interesting properties such as plasticity, transdifferentiation, and specificity. Mesenchymal cells of the dermis, hypodermis, and other sources are currently being investigated to promote regeneration. Conclusions Because skin stem cells are highly accessible from autologous sources and their immunological profile is unique, they are ideal for therapeutic approaches. Optimization of administrative routes requires more investigation own to the lack of a standard protocol.

  18. Molecular Mechanisms of Cell-cell Recognition

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-Huai

    2004-01-01

    Cell-cell recognition is the key for multicellular organisms to survive. This recognition critically depends on protein-protein interactions from opposing cell surfaces. Recent structural investigations reveal unique features of these cell surface receptors and how they interact. These interactions are specific, but usually relatively weak, with more hydrophilic forces involved in binding. The receptors appear to have specialized ways to present their key interacting elements for ligand-binding from the cell surface. Cell-cell contacts are multivalent. A large group of cell surface molecules are engaged in interactions. Characteristic weak interactions make possible for each individual molecule pair within the group to constantly associate-dissociate-reassociate, such that the cell-cell recognition becomes a dynamic process. The immunological synapse is a good example for immune receptors to be orchestrated in performing immunological function in a collective fashion.

  19. Photoelectrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Rauh, R. David (Newton, MA); Boudreau, Robert A. (Norton, MA)

    1983-06-14

    A photoelectrochemical cell comprising a sealed container having a light-transmitting window for admitting light into the container across a light-admitting plane, an electrolyte in the container, a photoelectrode in the container having a light-absorbing surface arranged to receive light from the window and in contact with the electrolyte, the surface having a plurality of spaced portions oblique to the plane, each portion having dimensions at least an order of magnitude larger than the maximum wavelength of incident sunlight, the total surface area of the surface being larger than the area of the plane bounded by the container, and a counter electrode in the container in contact with the electrolyte.

  20. NKT Cell Responses to B Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Junxin Li

    2014-04-01

    Full Text Available Natural killer T (NKT cells are a unique subset of CD1d-restricted T lymphocytes that express characteristics of both T cells and natural killer cells. NKT cells mediate tumor immune-surveillance; however, NKT cells are numerically reduced and functionally impaired in lymphoma patients. Many hematologic malignancies express CD1d molecules and co-stimulatory proteins needed to induce anti-tumor immunity by NKT cells, yet most tumors are poorly immunogenic. In this study, we sought to investigate NKT cell responses to B cell lymphoma. In the presence of exogenous antigen, both mouse and human NKT cell lines produce cytokines following stimulation by B cell lymphoma lines. NKT cell populations were examined ex vivo in mouse models of spontaneous B cell lymphoma, and it was found that during early stages, NKT cell responses were enhanced in lymphoma-bearing animals compared to disease-free animals. In contrast, in lymphoma-bearing animals with splenomegaly and lymphadenopathy, NKT cells were functionally impaired. In a mouse model of blastoid variant mantle cell lymphoma, treatment of tumor-bearing mice with a potent NKT cell agonist, α-galactosylceramide (α-GalCer, resulted in a significant decrease in disease pathology. Ex vivo studies demonstrated that NKT cells from α-GalCer treated mice produced IFN-γ following α-GalCer restimulation, unlike NKT cells from vehicle-control treated mice. These data demonstrate an important role for NKT cells in the immune response to an aggressive hematologic malignancy like mantle cell lymphoma.

  1. Photocontrol of the Functional Coupling between Photosynthesis and Stomatal Conductance in the Intact Leaf : Blue Light and Par-Dependent Photosystems in Guard Cells.

    Science.gov (United States)

    Zeiger, E; Field, C

    1982-08-01

    -dependent system in the guard cells may function as a specific light sensor while the PAR-dependent system supplies a CO(2)-modulated energy source providing functional coupling between the guard cells and the photosynthesizing mesophyll.

  2. nduced pluripotent stem cells and cell therapy

    Directory of Open Access Journals (Sweden)

    Banu İskender

    2013-12-01

    Full Text Available Human embryonic stem cells are derived from the inner cell mass of a blastocyst-stage embryo. They hold a huge promise for cell therapy with their self-renewing ability and pluripotency, which is known as the potential to differentiate into all cell types originating from three embryonic germ layers. However, their unique pluripotent feature could not be utilised for therapeutic purposes due to the ethical and legal problems during derivation. Recently, it was shown that the cells from adult tissues could be reverted into embryonic state, thereby restoring their pluripotent feature. This has strenghtened the possiblity of directed differentition of the reprogrammed somatic cells into the desired cell types in vitro and their use in regenerative medicine. Although these cells were termed as induced pluripotent cells, the mechanism of pluripotency has yet to be understood. Still, induced pluripotent stem cell technology is considered to be significant by proposing novel approaches in disease modelling, drug screening and cell therapy. Besides their self-renewing ability and their potential to differentiate into all cell types in a human body, they arouse a great interest in scientific world by being far from the ethical concerns regarding their embryonic counterparts and their unique feature of being patient-specific in prospective cell therapies. In this review, induced pluripotent stem cell technology and its role in cell-based therapies from past to present will be discussed. J Clin Exp Invest 2013; 4 (4: 550-561

  3. Modeling cell-in-cell structure into its biological significance

    OpenAIRE

    He, M-f; Wang, S.; Wang, Y; Wang, X-N.

    2013-01-01

    Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ‘entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintainin...

  4. Global warming increases the interspecific competitiveness of the invasive plant alligator weed, Alternanthera philoxeroides.

    Science.gov (United States)

    Wu, Hao; Ismail, Mohannad; Ding, Jianqing

    2017-01-01

    Global warming could accelerate the spread of invasive species to higher latitudes and intensify their effects on native species. Here, we report results of two years of field surveys along a latitudinal gradient (21°N to 31°N) in southern China, to determine the species structure of the invasive plant Alternanthera philoxeroides community. We also performed a replacement series experiment (mono and mixed) to evaluate the effects of elevated temperature on the competitiveness of A. philoxeroides with the native co-occurring species Digitaria sanguinalis. In the field survey, we found that the dominance of A. philoxeroides increased with increasing of latitude gradient while cover of D. sanguinalis decreased. In monospecific plantings, artificial warming reduced the length of D. sanguinalis roots. In mixed plantings, warming reduced both A. philoxeroides abundance and D. sanguinalis stem length when A. philoxeroides was more prevalent in the planting. Warming also significantly reduced D. sanguinalis biomass, but increased that of A. philoxeroides. In addition, elevated temperatures significantly reduced the relative yield (RY) of D. sanguinalis, particularly when A. philoxeroides was planted in higher proportion in the plot. These results suggest that the invasiveness of A. philoxeroides increased with increasing latitude, and that warming may increase the effectiveness of its interspecific competition with D. sanguinalis. Hence, under global warming conditions, the harm to native species from A. philoxeroides would increase at higher latitudes. Our findings are critical for predicting the invasiveness of alien species under climate change. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Tumor cell "dead or alive": caspase and survivin regulate cell death, cell cycle and cell survival.

    Science.gov (United States)

    Suzuki, A; Shiraki, K

    2001-04-01

    Cell death and cell cycle progression are two sides of the same coin, and these two different phenomenons are regulated moderately to maintain the cellular homeostasis. Tumor is one of the disease states produced as a result of the disintegrated regulation and is characterized as cells showing an irreversible progression of cell cycle and a resistance to cell death signaling. Several investigations have been performed for the understanding of cell death or cell cycle, and cell death research has remarkably progressed in these 10 years. Caspase is a nomenclature referring to ICE/CED-3 cysteine proteinase family and plays a central role during cell death. Recently, several investigations raised some possible hypotheses that caspase is also involved in cell cycle regulation. In this issue, therefore, we review the molecular basis of cell death and cell cycle regulated by caspase in tumor, especially hepatocellular carcinoma cells.

  6. Nanostructured Solar Cells.

    Science.gov (United States)

    Chen, Guanying; Ning, Zhijun; Ågren, Hans

    2016-08-09

    We are glad to announce the Special Issue "Nanostructured Solar Cells", published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

  7. Cell death pathways in directly irradiated cells and cells exposed to medium from irradiated cells.

    Science.gov (United States)

    Jella, Kishore Kumar; Garcia, Amaya; McClean, Brendan; Byrne, Hugh J; Lyng, Fiona M

    2013-03-01

    The aim of this study was to compare levels of apoptosis, necrosis, mitotic cell death and senescence after treatment with both direct radiation and irradiated cell conditioned medium. Human keratinocytes (HaCaT cell line) were irradiated (0.005, 0.05 and 0.5 Gy) using a cobalt 60 teletherapy unit. For bystander experiments, the medium was harvested from donor HaCaT cells 1 hour after irradiation and transferred to recipient HaCaT cells. Clonogenic assay, apoptosis, necrosis, mitotic cell death, senescence and cell cycle analysis were measured in both directly irradiated cells and bystander cells A reduction in cell survival was observed for both directly irradiated cells and irradiated cell conditioned medium (ICCM)-treated cells. Early apoptosis and necrosis was observed predominantly after direct irradiation. An increase in the number of cells in G2/M phase was observed at 6 and 12 h which led to mitotic cell death after 72 h following direct irradiation and ICCM treatment. No senescence was observed in the HaCaT cell line following either direct irradiation or treatment with ICCM. This study has shown that directly irradiated cells undergo apoptosis, necrosis and mitotic cell death whereas ICCM-treated cells predominantly undergo mitotic cell death.

  8. Cell culture purity issues and DFAT cells

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Shengjuan [College of Animal Science and Technology, Northwest A and F University, Yangling, Shaanxi Province 712100 (China); Department of Animal Sciences, Washington State University, Pullman, WA 99164 (United States); Bergen, Werner G. [Program in Cellular and Molecular Biosciences/Department of Animal Sciences, Auburn University, Auburn, AL 36849 (United States); Hausman, Gary J. [Animal Science Department, University of Georgia, Athens, GA 30602-2771 (United States); Zan, Linsen, E-mail: zanls@yahoo.com.cn [College of Animal Science and Technology, Northwest A and F University, Yangling, Shaanxi Province 712100 (China); Dodson, Michael V., E-mail: dodson@wsu.edu [Department of Animal Sciences, Washington State University, Pullman, WA 99164 (United States)

    2013-04-12

    Highlights: •DFAT cells are progeny cells derived from dedifferentiated mature adipocytes. •Common problems in this research is potential cell contamination of initial cultures. •The initial cell culture purity is crucial in DFAT cell research field. -- Abstract: Dedifferentiation of mature adipocytes, in vitro, has been pursued/documented for over forty years. The subsequent progeny cells are named dedifferentiated adipocyte-derived progeny cells (DFAT cells). DFAT cells are proliferative and likely to possess mutilineage potential. As a consequence, DFAT cells and their progeny/daughter cells may be useful as a potential tool for various aspects of tissue engineering and as potential vectors for the alleviation of several disease states. Publications in this area have been increasing annually, but the purity of the initial culture of mature adipocytes has seldom been documented. Consequently, it is not always clear whether DFAT cells are derived from dedifferentiated mature (lipid filled) adipocytes or from contaminating cells that reside in an impure culture.

  9. Processes modulating calcium distribution in citrus leaves. An investigation using x-ray microanalysis with strontium as a tracer.

    Science.gov (United States)

    Storey, Richard; Leigh, Roger A

    2004-11-01

    Citrus leaves accumulate large amounts of calcium that must be compartmented effectively to prevent stomatal closure by extracellular Ca2+ and interference with Ca(2+)-based cell signaling pathways. Using x-ray microanalysis, the distribution of calcium between vacuoles in different cell types of leaves of rough lemon (Citrus jambhiri Lush.) was investigated. Calcium was accumulated principally in palisade, spongy mesophyll, and crystal-containing idioblast cells. It was low in epidermal and bundle sheath cells. Potassium showed the reverse distribution. Rubidium and strontium were used as tracers to examine the pathways by which potassium and calcium reached these cells. Comparisons of strontium and calcium distribution indicated that strontium is a good tracer for calcium, but rubidium did not mirror the potassium distribution pattern. The amount of strontium accumulated was highest in palisade cells, lowest in bundle sheath and epidermal cells, and intermediate in the spongy mesophyll. Accumulation of strontium in palisade and spongy mesophyll was accompanied by loss of potassium from these cells and its accumulation in the bundle sheath. Strontium moved apoplastically from the xylem to all cell types, and manipulation of water loss from the adaxial leaf surface suggested that diffusion is responsible for strontium movement to this side of the leaf. The results highlight the importance of palisade and spongy mesophyll as repositories for calcium and suggest that calcium distribution between different cell types is the result of differential rates of uptake. This tracer technique can provide important information about the ion uptake and accumulation properties of cells in intact leaves.

  10. Electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Heuts, J.J.F.G.; Willems, J.J.G.S.A.

    1987-10-13

    An electrochemical cell is described comprising a negative electrode. The electrochemically active material of which consists of an intermetallic compound forming a hydride with hydrogen, which compound has the CaCu/sub 5/-structure and the compositional formula AB/sub m/C/sub n/, where m+n is between 4.8 and 5.4, where n is between 0.05 and 0.6, in which A consists of Misch-metal or of one or more elements selected from the group consisting of Y, Ti, Hf, Zr, Ca, Th, La and the remaining rare earth metals, in which the total atomic quantities of the elements Y, Ti, Hf and Zr may not be more than 40% of A. B consists of two or more elements selected from the group formed by Ni, Co, Cu, Fe and Mn, where the maximum atomic quantity per gram atom of A is for Ni: 3.5, for Co:3.5, for Cu:3.5, for Fe:2.0 and for Mn:1.0, and C consists of one or more elements selected from the group formed by Al, Cr and Si in the indicated atomic quantities: Al:0.05-0.6, Cr:0.05-0.5 and Si:0.05-0.5, characterized in that the electrochemically active material additionally comprises one or more metals selected from the group formed by Pd, Pt, Ir and Rh, the atomic quantity per gram atom of A being from 0.001 to 0.5.

  11. CELL RESEARCH

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    REVIEWSInducible resistance to Fas-mediated apoptosis in B cells…………………………………ROTHSTEIN Thomas L (245)Executionary pathway for apoptosis: lessons from mutant mice………………………………………WOO Minna, Razqallah Hakem, Tak W Mak (267)The SHP-2 tyrosine phosphatase: Signaling mechanisms and biological functions…………………………………QU Cheng Kui (279)REGULAR ARTICLESTemperature dependent expression of cdc2 and cyclin B1 in spermatogenic cells during spermatogenesis…………………………KONG Wei Hua, Zheng GU, Jining LU, Jiake TSO (289)Transgenic mice overexpressing γ-aminobutyric acid transporter subtype I develop obesity…………………………………MA Ying Hua, Jia Hua HU, Xiao Gang ZHOU, Ruo Wang ZENG, Zhen Tong MEI, Jian FEI, Li He GUO (303)Genetic aberration in primary hepatocellular carcinoma: correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23………………………………………WANG Gang, Chang Hui HUANG, Yan ZHAO, Ling CAI, Ying WANG, Shi Jin XIU, Zheng Wen JIANG, Shuang YANG, Xin Tai ZHAO, Wei HUANG, Jian Ren GU (311)Identification and genetic mapping of four novel genes that regulate leaf deve- lopment in Arabidopsis………………………………………………SUN Yue, Wei ZHANG, Feng Ling LI, Ying Li GUO, Tian Lei LIU, Hai HUANG (325)NOTICE FOR CONTRIBUTORS…………………………………(337)CONTENTS of Vol. 10, 2000…………………………………………………(338)

  12. Mammary stem cells have myoepithelial cell properties

    Science.gov (United States)

    Prater, Michael D.; Petit, Valérie; Russell, I. Alasdair; Giraddi, Rajshekhar; Shehata, Mona; Menon, Suraj; Schulte, Reiner; Kalajzic, Ivo; Rath, Nicola; Olson, Michael F.; Metzger, Daniel; Faraldo, Marisa M.; Deugnier, Marie-Ange; Glukhova, Marina A.; Stingl, John

    2014-01-01

    Contractile myoepithelial cells dominate the basal layer of the mammary epithelium and are considered to be differentiated cells. However, we observe that up to 54% of single basal cells can form colonies when seeded into adherent culture in the presence of agents that disrupt acin-myosin interactions, and on average, 65% of the single-cell-derived basal colonies can repopulate a mammary gland when transplanted in vivo. This indicates that a high proportion of basal myoepithelial cells can give rise to a mammary repopulating unit (MRU). We demonstrate that myoepithelial cells, flow-sorted using 2 independent myoepithelial-specific reporter strategies, have MRU capacity. Using an inducible lineage tracing approach we follow the progeny of α-smooth muscle actin-expressing myoepithelial cells and show that they function as long-lived lineage-restricted stem cells in the virgin state and during pregnancy. PMID:25173976

  13. Mammary stem cells have myoepithelial cell properties.

    Science.gov (United States)

    Prater, Michael D; Petit, Valérie; Alasdair Russell, I; Giraddi, Rajshekhar R; Shehata, Mona; Menon, Suraj; Schulte, Reiner; Kalajzic, Ivo; Rath, Nicola; Olson, Michael F; Metzger, Daniel; Faraldo, Marisa M; Deugnier, Marie-Ange; Glukhova, Marina A; Stingl, John

    2014-10-01

    Contractile myoepithelial cells dominate the basal layer of the mammary epithelium and are considered to be differentiated cells. However, we observe that up to 54% of single basal cells can form colonies when seeded into adherent culture in the presence of agents that disrupt actin-myosin interactions, and on average, 65% of the single-cell-derived basal colonies can repopulate a mammary gland when transplanted in vivo. This indicates that a high proportion of basal myoepithelial cells can give rise to a mammary repopulating unit (MRU). We demonstrate that myoepithelial cells, flow-sorted using two independent myoepithelial-specific reporter strategies, have MRU capacity. Using an inducible lineage-tracing approach we follow the progeny of myoepithelial cells that express α-smooth muscle actin and show that they function as long-lived lineage-restricted stem cells in the virgin state and during pregnancy.

  14. Cell culture purity issues and DFAT cells.

    Science.gov (United States)

    Wei, Shengjuan; Bergen, Werner G; Hausman, Gary J; Zan, Linsen; Dodson, Michael V

    2013-04-12

    Dedifferentiation of mature adipocytes, in vitro, has been pursued/documented for over forty years. The subsequent progeny cells are named dedifferentiated adipocyte-derived progeny cells (DFAT cells). DFAT cells are proliferative and likely to possess mutilineage potential. As a consequence, DFAT cells and their progeny/daughter cells may be useful as a potential tool for various aspects of tissue engineering and as potential vectors for the alleviation of several disease states. Publications in this area have been increasing annually, but the purity of the initial culture of mature adipocytes has seldom been documented. Consequently, it is not always clear whether DFAT cells are derived from dedifferentiated mature (lipid filled) adipocytes or from contaminating cells that reside in an impure culture.

  15. Cell Membrane Softening in Cancer Cells

    Science.gov (United States)

    Schmidt, Sebastian; Händel, Chris; Käs, Josef

    Biomechanical properties are useful characteristics and regulators of the cell's state. Current research connects mechanical properties of the cytoskeleton to many cellular processes but does not investigate the biomechanics of the plasma membrane. We evaluated thermal fluctuations of giant plasma membrane vesicles, directly derived from the plasma membranes of primary breast and cervical cells and observed a lowered rigidity in the plasma membrane of malignant cells compared to non-malignant cells. To investigate the specific role of membrane rigidity changes, we treated two cell lines with the Acetyl-CoA carboxylase inhibitor Soraphen A. It changed the lipidome of cells and drastically increased membrane stiffness by up regulating short chained membrane lipids. These altered cells had a decreased motility in Boyden chamber assays. Our results indicate that the thermal fluctuations of the membrane, which are much smaller than the fluctuations driven by the cytoskeleton, can be modulated by the cell and have an impact on adhesion and motility.

  16. Cell sheet engineering

    Directory of Open Access Journals (Sweden)

    Masayuki Yamato

    2004-05-01

    Full Text Available We have developed ‘cell sheet engineering’ in order to avoid the limitations of tissue reconstruction using biodegradable scaffolds or single cell suspension injection. Our concept is tissue reconstruction, not from single cells, but from cell sheets. Cell sheets are prepared using temperature-responsive culture dishes. Temperature-responsive polymers are covalently grafted onto the dishes, allowing various types of cells to adhere and proliferate at 37°C. The cells spontaneously detach when the temperature is reduced below 32°C without the need for proteolytic enzymes. The confluent cells are noninvasively harvested as single, contiguous cell sheets with intact cell-cell junctions and deposited extracellular matrix (ECM. We have used these harvested cell sheets for various tissue reconstructions, including ocular surfaces, periodontal ligaments, cardiac patches, and bladder augmentation.

  17. Lung cancer - small cell

    Science.gov (United States)

    Cancer - lung - small cell; Small cell lung cancer; SCLC ... About 15% of all lung cancer cases are SCLC. Small cell lung cancer is slightly more common in men than women. Almost all cases of SCLC are ...

  18. Stem Cell Information: Glossary

    Science.gov (United States)

    ... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... here Home » Glossary Back to top Glossary Adult stem cell Astrocyte Blastocoel Blastocyst Bone marrow stromal cells Bone ...

  19. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  20. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  1. Natural Killer Cell Memory

    National Research Council Canada - National Science Library

    O'Sullivan, Timothy E; Sun, Joseph C; Lanier, Lewis L

    2015-01-01

    Natural killer (NK) cells have historically been considered short-lived cytolytic cells that can rapidly respond against pathogens and tumors in an antigen-independent manner and then undergo cell death...

  2. Fuel cells: A survey

    Science.gov (United States)

    Crowe, B. J.

    1973-01-01

    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  3. CellFinder: a cell data repository.

    Science.gov (United States)

    Stachelscheid, Harald; Seltmann, Stefanie; Lekschas, Fritz; Fontaine, Jean-Fred; Mah, Nancy; Neves, Mariana; Andrade-Navarro, Miguel A; Leser, Ulf; Kurtz, Andreas

    2014-01-01

    CellFinder (http://www.cellfinder.org) is a comprehensive one-stop resource for molecular data characterizing mammalian cells in different tissues and in different development stages. It is built from carefully selected data sets stemming from other curated databases and the biomedical literature. To date, CellFinder describes 3394 cell types and 50 951 cell lines. The database currently contains 3055 microscopic and anatomical images, 205 whole-genome expression profiles of 194 cell/tissue types from RNA-seq and microarrays and 553 905 protein expressions for 535 cells/tissues. Text mining of a corpus of >2000 publications followed by manual curation confirmed expression information on ∼900 proteins and genes. CellFinder's data model is capable to seamlessly represent entities from single cells to the organ level, to incorporate mappings between homologous entities in different species and to describe processes of cell development and differentiation. Its ontological backbone currently consists of 204 741 ontology terms incorporated from 10 different ontologies unified under the novel CELDA ontology. CellFinder's web portal allows searching, browsing and comparing the stored data, interactive construction of developmental trees and navigating the partonomic hierarchy of cells and tissues through a unique body browser designed for life scientists and clinicians.

  4. Snail modulates cell metabolism in MDCK cells

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  5. Cell aggregation and sedimentation.

    Science.gov (United States)

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  6. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  7. Nanostructured Solar Cells

    Science.gov (United States)

    Chen, Guanying; Ning, Zhijun; Ågren, Hans

    2016-01-01

    We are glad to announce the Special Issue “Nanostructured Solar Cells”, published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

  8. Squamous cell skin cancer

    Science.gov (United States)

    ... that reflect light more, such as water, sand, concrete, and areas that are painted white. The higher ... - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous ...

  9. Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest.

    Science.gov (United States)

    Kenzo, Tanaka; Ichie, Tomoaki; Yoneda, Reiji; Kitahashi, Yoshinori; Watanabe, Yoko; Ninomiya, Ikuo; Koike, Takayoshi

    2004-10-01

    Photosynthetic rate, nitrogen concentration and morphological properties of canopy leaves were studied in 18 trees, comprising five dipterocarp species, in a tropical rain forest in Sarawak, Malaysia. Photosynthetic rate at light saturation (Pmax) differed significantly across species, varying from 7 to 18 micro mol m(-2) s(-1). Leaf nitrogen concentration and morphological properties, such as leaf blade and palisade layer thickness, leaf mass per area (LMA) and surface area of mesophyll cells per unit leaf area (Ames/A), also varied significantly across species. Among the relationships with leaf characteristics, Pmax had the strongest correlation with leaf mesophyll parameters, such as palisade cell layer thickness (r2 = 0.76, P palisade layer, with up to five or more layers. We conclude that interspecific variation in photosynthetic capacity in tropical rain forest canopies is influenced more by leaf mesophyll structure than by leaf thickness, LMA or leaf nitrogen concentration.

  10. Profiles of photosynthesis within red and green leaves of Quintinia serrata.

    Science.gov (United States)

    Gould, Kevin S; Vogelmann, Thomas C; Han, Tao; Clearwater, Michael J

    2002-09-01

    We have measured photosynthesis at the cellular, tissue, and whole leaf levels to understand the role of anthocyanin pigments on patterns of light utilization. Profiles of chlorophyll fluorescence through sections of red and green leaves of Quintinia serrata showed that anthocyanins in the mesophyll restricted absorption of green light to the uppermost palisade mesophyll. The distribution was further restricted when anthocyanins were also present in the upper epidermis. Mesophyll cells located beneath a cyanic light-filter assumed the characteristic photosynthetic features of shade-adapted cells. As a result, red leaves showed a 23% reduction in CO2 assimilation under light-saturating conditions, and a lower threshold irradiance for light-saturation, relative to those of green leaves. The photosynthetic characteristics of red leaves are comparable to those of shade-acclimated plants.

  11. Cell mechanics: a dialogue

    Science.gov (United States)

    Tao, Jiaxiang; Li, Yizeng; Vig, Dhruv K.; Sun, Sean X.

    2017-03-01

    Under the microscope, eukaryotic animal cells can adopt a variety of different shapes and sizes. These cells also move and deform, and the physical mechanisms driving these movements and shape changes are important in fundamental cell biology, tissue mechanics, as well as disease biology. This article reviews some of the basic mechanical concepts in cells, emphasizing continuum mechanics description of cytoskeletal networks and hydrodynamic flows across the cell membrane. We discuss how cells can generate movement and shape changes by controlling mass fluxes at the cell boundary. These mass fluxes can come from polymerization/depolymerization of actin cytoskeleton, as well as osmotic and hydraulic pressure-driven flow of water across the cell membrane. By combining hydraulic pressure control with force balance conditions at the cell surface, we discuss a quantitative mechanism of cell shape and volume control. The broad consequences of this model on cell mechanosensation and tissue mechanics are outlined.

  12. Cell surface engineering of mesenchymal stem cells.

    Science.gov (United States)

    Sarkar, Debanjan; Zhao, Weian; Gupta, Ashish; Loh, Wei Li; Karnik, Rohit; Karp, Jeffrey M

    2011-01-01

    By leveraging the capacity to promote regeneration, stem cell therapies offer enormous hope for solving some of the most tragic illnesses, diseases, and tissue defects world-wide. However, a significant barrier to the effective implementation of cell therapies is the inability to target a large quantity of viable cells with high efficiency to tissues of interest. Systemic infusion is desired as it minimizes the invasiveness of cell therapy, and maximizes practical aspects of repeated doses. However, cell types such as mesenchymal stem cells exhibit a poor homing capability or lose their capacity to home following culture expansion (i.e. FASEB J 21:3197-3207, 2007; Circulation 108:863-868, 2003; Stroke: A Journal of Cerebral Circulation 32:1005-1011; Blood 104:3581-3587, 2004). To address this challenge, we have developed a simple platform technology to chemically attach cell adhesion molecules to the cell surface to improve the homing efficiency to specific tissues. This chemical approach involves a stepwise process including (1) treatment of cells with sulfonated biotinyl-N-hydroxy-succinimide to introduce biotin groups on the cell surface, (2) addition of streptavidin that binds to the biotin on the cell surface and presents unoccupied binding sites, and (3) attachment of biotinylated targeting ligands that promote adhesive interactions with vascular endothelium. Specifically, in our model system, a biotinylated cell rolling ligand, sialyl Lewisx (SLeX), found on the surface of leukocytes (i.e., the active site of the P-selectin glycoprotein ligand (PSGL-1)), is conjugated on MSC surface. The SLeX engineered MSCs exhibit a rolling response on a P-selectin coated substrate under shear stress conditions. This indicates that this approach can be used to potentially target P-selectin expressing endothelium in the more marrow or at sites of inflammation. Importantly, the surface modification has no adverse impact on MSCs' native phenotype including their multilineage

  13. Cancer stem cell-like cells from a single cell of oral squamous carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Felthaus, O. [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany); Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Ettl, T.; Gosau, M.; Driemel, O. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Brockhoff, G. [Department of Gynecology and Obstetrics, University of Regensburg (Germany); Reck, A. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Zeitler, K. [Institute of Pathology, University of Regensburg (Germany); Hautmann, M. [Department of Radiotherapy, University of Regensburg (Germany); Reichert, T.E. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Schmalz, G. [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany); Morsczeck, C., E-mail: christian.morsczeck@klinik.uni-regensburg.de [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany)

    2011-04-01

    Research highlights: {yields} Four oral squamous cancer cell lines (OSCCL) were analyzed for cancer stem cells (CSCs). {yields} Single cell derived colonies of OSCCL express CSC-marker CD133 differentially. {yields} Monoclonal cell lines showed reduced sensitivity for Paclitaxel. {yields} In situ CD133{sup +} cells are slow cycling (Ki67-) indicating a reduced drug sensitivity. {yields} CD133{sup +} and CSC-like cells can be obtained from single colony forming cells of OSCCL. -- Abstract: Resistance of oral squamous cell carcinomas (OSCC) to conventional chemotherapy or radiation therapy might be due to cancer stem cells (CSCs). The development of novel anticancer drugs requires a simple method for the enrichment of CSCs. CSCs can be enriched from OSCC cell lines, for example, after cultivation in serum-free cell culture medium (SFM). In our study, we analyzed four OSCC cell lines for the presence of CSCs. CSC-like cells could not be enriched with SFM. However, cell lines obtained from holoclone colonies showed CSC-like properties such as a reduced rate of cell proliferation and a reduced sensitivity to Paclitaxel in comparison to cells from the parental lineage. Moreover, these cell lines differentially expressed the CSC-marker CD133, which is also upregulated in OSCC tissues. Interestingly, CD133{sup +} cells in OSCC tissues expressed little to no Ki67, the cell proliferation marker that also indicates reduced drug sensitivity. Our study shows a method for the isolation of CSC-like cell lines from OSCC cell lines. These CSC-like cell lines could be new targets for the development of anticancer drugs under in vitro conditions.

  14. Insect Cell Culture

    NARCIS (Netherlands)

    Oers, van M.M.; Lynn, D.E.

    2010-01-01

    Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from lepidoptera

  15. Tracking adult stem cells

    NARCIS (Netherlands)

    Snippert, H.J.G.; Clevers, H.

    2011-01-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context,

  16. Insect Cell Culture

    NARCIS (Netherlands)

    Oers, van M.M.; Lynn, D.E.

    2010-01-01

    Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from lepidoptera

  17. T-Cell Lymphoma

    Science.gov (United States)

    Getting the Facts T-Cell Lymphoma Overview Lymphoma is the most common blood cancer. The two main forms of lymphoma are Hodgkin lymphoma ... develop into lymphomas: B-lymphocytes (B-cells) and T-lymphocytes (T-cells). T-cell lymphomas account for ...

  18. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Nora [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Vereb, Zoltan; Rajnavoelgyi, Eva [Department of Immunology, Medical and Health Science Centre, University of Debrecen, Debrecen (Hungary); Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Apati, Agota, E-mail: apati@kkk.org.hu [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  19. Individual cell sorting.

    Science.gov (United States)

    Stovel, R T; Sweet, R G

    1979-01-01

    Current cell sorting machines do not preserve the individual identity of processed cells; after analysis, the cells are assigned to a subpopulation where they are pooled with other similar cells. This paper reports progress on a system that sorts cells individually to precise locations on a microscope slide and preserves them for further observation with a light microscope while recording flow measurement data for each cell. Various electronic and mechanical modifications to an existing sorting machine are described that increase drop placement accuracy and permit individual cell sorting.

  20. Stem Cell Organoid Engineering

    Science.gov (United States)

    Yin, Xiaolei; Mead, Benjamin E.; Safaee, Helia; Langer, Robert; Karp, Jeffrey M.; Levy, Oren

    2016-01-01

    Organoid systems leverage the self-organizing properties of stem cells to create diverse multi-cellular tissue proxies. Most organoid models only represent single or partial components of a tissue, and it is often difficult to control the cell type, organization, and cell-cell/cell-matrix interactions within these systems. Herein, we discuss basic approaches to generate stem cell-based organoids, their advantages and limitations, and how bioengineering strategies can be used to steer the cell composition and their 3D organization within organoids to further enhance their utility in research and therapies. PMID:26748754

  1. Molten carbonate fuel cell

    Science.gov (United States)

    Kaun, T.D.; Smith, J.L.

    1986-07-08

    A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  2. Secreted effectors of the tomato leaf mould fungus Cladosporium fulvum are virulence factors that target host defense

    Science.gov (United States)

    Cladosporium fulvum is a biotrophic fungal pathogen that causes leaf mould of tomato. Inside the leaf, C. fulvum does not penetrate host cells or develop haustoria but remains confined to the intercellular space between mesophyll cells. Ten effector proteins that are secreted during host colonizatio...

  3. Innate Memory T cells

    Science.gov (United States)

    Jameson, Stephen C.; Lee, You Jeong; Hogquist, Kristin A.

    2015-01-01

    Memory T cells are usually considered to be a feature of a successful immune response against a foreign antigen, and such cells can mediate potent immunity. However, in mice, alternative pathways have been described, through which naïve T cells can acquire the characteristics and functions of memory T cells without encountering specific foreign antigen or the typical signals required for conventional T cell differentiation. Such cells reflect a response to the internal rather the external environment, and hence such cells are called innate memory T cells. In this review, we describe how innate memory subsets were identified, the signals that induce their generation and their functional properties and potential role in the normal immune response. The existence of innate memory T cells in mice raises questions about whether parallel populations exist in humans, and we discuss the evidence for such populations during human T cell development and differentiation. PMID:25727290

  4. Chicken NK cell receptors.

    Science.gov (United States)

    Straub, Christian; Neulen, Marie-Luise; Sperling, Beatrice; Windau, Katharina; Zechmann, Maria; Jansen, Christine A; Viertlboeck, Birgit C; Göbel, Thomas W

    2013-11-01

    Natural killer cells are innate immune cells that destroy virally infected or transformed cells. They recognize these altered cells by a plethora of diverse receptors and thereby differ from other lymphocytes that use clonally distributed antigen receptors. To date, several receptor families that play a role in either activating or inhibiting NK cells have been identified in mammals. In the chicken, NK cells have been functionally and morphologically defined, however, a conclusive analysis of receptors involved in NK cell mediated functions has not been available. This is partly due to the low frequencies of NK cells in blood or spleen that has hampered their intensive characterization. Here we will review recent progress regarding the diverse NK cell receptor families, with special emphasis on novel families identified in the chicken genome with potential as chicken NK cell receptors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Ganglion cell like cells, diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Anand Shankar Ammanagi

    2013-01-01

    Full Text Available We report a case of cutaneous swelling found on the left anterior axillary fold of a 41-year-old man. Gross examination of specimen excised from the dermis showed a well-circumscribed nodule histologically composed of spindle cells with interspersed ganglion cell like cells. On hematoxylin and eosine (H and E staining it was diagnosed as ganglioneuroma. Ganglioneuromas are rare, benign, fully differentiated tumors that contain mature schwann cells, ganglion cells, fibrous tissue, and nerve fibers. They are commonly found along the paravertebral sympathetic ganglia and sometimes in the adrenal medulla. However primary cutaneous ganglioneuroma is an extremely rare tumor. Immunohistochemical workup revealed a fibroblastic origin and hence the case was diagnosed as fibromatosis with ganglion cell like fibroblasts. This case report suggests that the features considered diagnostic of ganglioneuromas can occur in other cutaneous lesions and, therefore, this diagnosis cannot be offered only on the basis of H and E.

  6. Generation of iPS Cells from Granulosa Cells.

    Science.gov (United States)

    Mao, Jian; Liu, Lin

    2016-01-01

    Various types of somatic cells can be reprogrammed to induced pluripotent stem (iPS) cells. Somatic stem cells may generate iPS cells more efficiently than do differentiated cells. We show that granulosa cells exhibit characteristic of somatic stem cells and can be reprogrammed to iPS cells more efficiently or with few factors. Here, we describe generation of mouse and pig iPS cells from granulosa cells with high efficiency.

  7. B cell helper assays.

    Science.gov (United States)

    Abrignani, Sergio; Tonti, Elena; Casorati, Giulia; Dellabona, Paolo

    2009-01-01

    Activation, proliferation and differentiation of naïve B lymphocytes into memory B cells and plasma cells requires engagement of the B cell receptor (BCR) coupled to T-cell help (1, 2). T cells deliver help in cognate fashion when they are activated upon recognition of specific MHC-peptide complexes presented by B cells. T cells can also deliver help in a non-cognate or bystander fashion, when they do not find specific MHC-peptide complexes on B cells and are activated by alternative mechanisms. T-cell dependent activation of B cells can be studied in vitro by experimental models called "B cell helper assays" that are based on the co-culture of B cells with activated T cells. These assays allow to decipher the molecular bases for productive T-dependent B cell responses. We show here examples of B cell helper assays in vitro, which can be reproduced with any subset of T lymphocytes that displays the appropriate helper signals.

  8. Mast cells enhance T cell activation: Importance of mast cell-derived TNF

    Science.gov (United States)

    Nakae, Susumu; Suto, Hajime; Kakurai, Maki; Sedgwick, Jonathon D.; Tsai, Mindy; Galli, Stephen J.

    2005-05-01

    Mast cells are not only important effector cells in immediate hypersensitivity reactions and immune responses to pathogens but also can contribute to T cell-mediated disorders. However, the mechanisms by which mast cells might influence T cells in such settings are not fully understood. We find that mast cells can enhance proliferation and cytokine production in multiple T cell subsets. Mast cell-dependent enhancement of T cell activation can be promoted by FcRI-dependent mast cell activation, TNF production by both mast cells and T cells, and mast cell-T cell contact. However, at high concentrations of cells, mast cells can promote T cell activation independent of IgE or TNF. Finally, mast cells also can promote T cell activation by means of soluble factors. These findings identify multiple mechanisms by which mast cells can influence T cell proliferation and cytokine production. allergy | asthma | autoimmunity | cytokines | immune response

  9. Single cell mechanics of keratinocyte cells.

    Science.gov (United States)

    Lulevich, Valentin; Yang, Hsin-ya; Isseroff, R Rivkah; Liu, Gang-yu

    2010-11-01

    Keratinocytes represent the major cell type of the uppermost layer of human skin, the epidermis. Using AFM-based single cell compression, the ability of individual keratinocytes to resist external pressure and global rupturing forces is investigated and compared with various cell types. Keratinocytes are found to be 6-70 times stiffer than other cell types, such as white blood, breast epithelial, fibroblast, or neuronal cells, and in contrast to other cell types they retain high mechanic strength even after the cell's death. The absence of membrane rupturing peaks in the force-deformation profiles of keratinocytes and their high stiffness during a second load cycle suggests that their unique mechanical resistance is dictated by the cytoskeleton. A simple analytical model enables the quantification of Young's modulus of keratinocyte cytoskeleton, as high as 120-340 Pa. Selective disruption of the two major cytoskeletal networks, actin filaments and microtubules, does not significantly affect keratinocyte mechanics. F-actin is found to impact cell deformation under pressure. During keratinocyte compression, the plasma membrane stretches to form peripheral blebs. Instead of blebbing, cells with depolymerized F-actin respond to pressure by detaching the plasma membrane from the cytoskeleton underneath. On the other hand, the compression force of keratinocytes expressing a mutated keratin (cell line, KEB-7) is 1.6-2.2 times less than that for the control cell line that has normal keratin networks. Therefore, we infer that the keratin intermediate filament network is responsible for the extremely high keratinocyte stiffness and resilience. This could manifest into the rugged protective nature of the human epidermis.

  10. Leaf biomechanics, morphology, and anatomy of the deciduous mesophyte Prunus serrulata (Rosaceae) and the evergreen sclerophyllous shrub Heteromeles arbutifolia (Rosaceae).

    Science.gov (United States)

    Balsamo, Ronald A; Bauer, Aaron M; Davis, Stephen D; Rice, Benita M

    2003-01-01

    Leaf tensile properties were compared between the mesic deciduous tree Prunus serrulata (var. "Kwanzan") and the xeric and sclerophyllous chaparral evergreen shrub Heteromeles arbutifolia (M. Roem). All values for biomechanical parameters for H. arbutifolia were significantly greater than those of P. serrulata. The fracture planes also differed between the two species with P. serrulata fracturing along the secondary veins, while H. arbutifolia most often fractured across the leaf irrespective of the vein or mesophyll position, thus yielding qualitative differences in the stress-strain curves of the two species. Anatomically, P. serrulata exhibits features typical for a deciduous mesophytic leaf such as a thin cuticle, a single layer of palisade mesophyll, isodiametric spongy mesophyll, and extensive reticulation of the laminar veins. Heteromeles arbutifolia leaves, however, are typically two- to three-fold thicker with a 35% higher dry mass/fresh mass ratio. The vascular tissue is restricted to the interface of the palisade and spongy mesophyll near the center of the leaf. Both epidermal layers have a thick cuticle. The palisade mesophyll is tightly packed and two to three layers thick. The spongy mesophyll cells are ameboid in shape and tightly interlinked both to other spongy cells as well as to the overlying palisade layer. We conclude that the qualitative and quantitative biomechanical differences between the leaves of these two species are likely due to a complex interaction of internal architectural arrangement and the physical/chemical differences in the properties of their respective cell walls. These studies illustrate the importance that morphological and anatomical correlates play with mechanical behavior in plant material and ultimately reflect adaptations present in the leaves of chaparral shrubs that are conducive to surviving in arid environments.

  11. Lung Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Sharon R. Pine

    2008-01-01

    Full Text Available Lung cancer remains a major cause of cancer-related lethality because of high incidence and recurrence in spite of significant advances in staging and therapies. Recent data indicates that stem cells situated throughout the airways may initiate cancer formation. These putative stem cells maintain protumorigenic characteristics including high proliferative capacity, multipotent differentiation, drug resistance and long lifespan relative to other cells. Stem cell signaling and differentiation pathways are maintained within distinct cancer types, and destabilization of this machinery may participate in maintenance of cancer stem cells. Characterization of lung cancer stem cells is an area of active research and is critical for developing novel therapies. This review summarizes the current knowledge on stem cell signaling pathways and cell markers used to identify the lung cancer stem cells.

  12. Tracking adult stem cells.

    Science.gov (United States)

    Snippert, Hugo J; Clevers, Hans

    2011-02-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context, rather than outside their natural environment. The mouse is an attractive model in which to study adult mammalian stem cells, as numerous experimental systems and genetic tools are available. In this review, we describe strategies commonly used to identify and functionally characterize adult stem cells in mice and discuss their potential, limitations and interpretations, as well as how they have informed our understanding of adult stem-cell biology. An accurate interpretation of physiologically relevant stem-cell assays is crucial to identify adult stem cells and elucidate how they self-renew and give rise to differentiated progeny.

  13. Plant stem cell niches.

    Science.gov (United States)

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  14. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  15. Tetraspanins in Cell Migration

    Science.gov (United States)

    Jiang, Xupin; Zhang, Jiaping; Huang, Yuesheng

    2015-01-01

    Tetraspanins are a superfamily of small transmembrane proteins that are expressed in almost all eukaryotic cells. Through interacting with one another and with other membrane and intracellular proteins, tetraspanins regulate a wide range of proteins such as integrins, cell surface receptors, and signaling molecules, and thereby engage in diverse cellular processes ranging from cell adhesion and migration to proliferation and differentiation. In particular, tetraspanins modulate the function of proteins involved in all determining factors of cell migration including cell–cell adhesion, cell–ECM adhesion, cytoskeletal protrusion/contraction, and proteolytic ECM remodeling. We herein provide a brief overview of collective in vitro and in vivo studies of tetraspanins to illustrate their regulatory functions in the migration and trafficking of cancer cells, vascular endothelial cells, skin cells (keratinocytes and fibroblasts), and leukocytes. We also discuss the involvement of tetraspanins in various pathologic and remedial processes that rely on cell migration and their potential value as targets for therapeutic intervention. PMID:26091149

  16. Stem cells in urology.

    Science.gov (United States)

    Aboushwareb, Tamer; Atala, Anthony

    2008-11-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.

  17. Apigenin inhibits renal cell carcinoma cell proliferation.

    Science.gov (United States)

    Meng, Shuai; Zhu, Yi; Li, Jiang-Feng; Wang, Xiao; Liang, Zhen; Li, Shi-Qi; Xu, Xin; Chen, Hong; Liu, Ben; Zheng, Xiang-Yi; Xie, Li-Ping

    2017-03-21

    Apigenin, a natural flavonoid found in vegetables and fruits, has antitumor activity in several cancer types. The present study evaluated the effects and mechanism of action of apigenin in renal cell carcinoma (RCC) cells. We found that apigenin suppressed ACHN, 786-0, and Caki-1 RCC cell proliferation in a dose- and time-dependent manner. A comet assay suggested that apigenin caused DNA damage in ACHN cells, especially at higher doses, and induced G2/M phase cell cycle arrest through ATM signal modulation. Small interfering RNA (siRNA)-mediated p53 knockdown showed that apigenin-induced apoptosis was likely p53 dependent. Apigenin anti-proliferative effects were confirmed in an ACHN cell xenograft mouse model. Apigenin treatment reduced tumor growth and volume in vivo, and immunohistochemical staining revealed lower Ki-67 indices in tumors derived from apigenin-treated mice. These findings suggest that apigenin exposure induces DNA damage, G2/M phase cell cycle arrest, p53 accumulation and apoptosis, which collectively suppress ACHN RCC cell proliferation in vitro and in vivo. Given its antitumor effects and low in vivo toxicity, apigenin is a highly promising agent for treatment of RCC.

  18. Cell shape recognition by colloidal cell imprints

    NARCIS (Netherlands)

    Borovička, Josef; Stoyanov, S.D.; Paunov, V.N.

    2015-01-01

    The results presented in this study are aimed at the theoretical estimate of the interactions between a spherical microbial cell and the colloidal cell imprints in terms of the Derjaguin, Landau, Vervey, and Overbeek (DLVO) surface forces. We adapted the Derjaguin approximation to take into accou

  19. Are mesenchymal stromal cells immune cells?

    NARCIS (Netherlands)

    M.J. Hoogduijn (Martin)

    2015-01-01

    textabstractMesenchymal stromal cells (MSCs) are considered to be promising agents for the treatment of immunological disease. Although originally identified as precursor cells for mesenchymal lineages, in vitro studies have demonstrated that MSCs possess diverse immune regulatory capacities. Pre-cl

  20. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-01-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitu

  1. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

    Directory of Open Access Journals (Sweden)

    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  2. Cell-ECM traction force modulates endogenous tension at cell-cell contacts

    National Research Council Canada - National Science Library

    Venkat Maruthamuthu; Benedikt Sabass; Ulrich S. Schwarz; Margaret L. Gardel; Shu Chien

    2011-01-01

    .... A direct relationship between the total cellular traction force on the ECM and the endogenous cell-cell force exists, indicating that the cell-cell tension is a constant fraction of the cell-ECM traction...

  3. Natural Killer Cell Memory.

    Science.gov (United States)

    O'Sullivan, Timothy E; Sun, Joseph C; Lanier, Lewis L

    2015-10-20

    Natural killer (NK) cells have historically been considered short-lived cytolytic cells that can rapidly respond against pathogens and tumors in an antigen-independent manner and then undergo cell death. Recently, however, NK cells have been shown to possess traits of adaptive immunity and can acquire immunological memory in a manner similar to that of T and B cells. In this review, we discuss evidence of NK cell memory and the mechanisms involved in the generation and survival of these innate lymphocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Pluripotent stem cells for Schwann cell engineering.

    Science.gov (United States)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-04-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitulating the various stages of in vivo neural crest formation and SC differentiation. In this review, we survey the cellular and molecular mechanisms underlying these in vivo processes. We then focus on the current in vitro strategies for generating SCs from two sources of pluripotent stem cells, namely embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). Different methods for SC engineering from ESCs and iPSCs are reviewed and suggestions are proposed for optimizing the existing protocols. Potential safety issues regarding the clinical application of iPSC-derived SCs are discussed as well. Lastly, we will address future aspects of SC engineering.

  5. Differential activity of Plasma and Vacuolar Membrane Transporters contributes to Genotypic Differences in Salinity Tolerance in a Halophyte Species, Chenopodium quinoa

    DEFF Research Database (Denmark)

    Bonales-Alatorre, Edgar; Pottosin, Igor; Shabala, Lana

    2013-01-01

    Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow...... (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na+ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two....... These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce...

  6. Anatomy of Begonia lucernae Wettst. (Begoniaceae leaf

    Directory of Open Access Journals (Sweden)

    Rodica BERCU

    2015-06-01

    Full Text Available The paper presents anatomical aspects concerning the leaf structure of Begonia lucernae Wettst. belonging to Begoniaceae family. Anatomically, the petiole has a unistratous epidermis and a differentiated mesophyll. The vascular system is fascicular type with a large number of collateral bundles placed into a basic tissue. The lamina is composed of an upper and a lower epidermis and hypodermis as well and the mesophyll. The mesophyll differentiated into palisade tissue and spongy tissue with the same vascular bundle structure such as those of the petiole but with foliar arrangement of the conductive tissues. Stomata are present to the lower epidermis. Paradermal section discloses stright walls epidermal cells and anisocytic stomata. It was calculated the number of stomata/mm2 of leaf surface and the stomatal index as well.

  7. The cell cycle as a brake for β-cell regeneration from embryonic stem cells.

    Science.gov (United States)

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-13

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle machinery. Both β cells and ES cells possess unique cell cycle machinery yet with significant contrasts. In this review, we compare the cell cycle control mechanisms in both ES cells and β cells, and highlight the fundamental differences between pluripotent cells of embryonic origin and differentiated β cells. Through critical analysis of the differences of the cell cycle between these two cell types, we propose that the cell cycle of ES cells may act as a brake for β-cell regeneration. Based on these differences, we discuss the potential of modulating the cell cycle of ES cells for the large-scale generation of functionally mature β cells in vitro. Further understanding of the factors that modulate the ES cell cycle will lead to new approaches to enhance the production of functional mature insulin-producing cells, and yield a reliable system to generate bona fide β cells in vitro.

  8. Amino Acid transport in protoplasts isolated from soybean leaves.

    Science.gov (United States)

    Vernooy, C D; Lin, W

    1986-05-01

    We isolated large quantities of mesophyll protoplasts from source and sink leaves of soybean plants and examined them for amino acid uptake. Accumulation of amino acids in isolated protoplasts was linear for at least 40 minutes. Uptake kinetics revealed the presence of both saturable and linear components. Increasing external pH decreases the uptake. The uncoupler, carbonyl cyanide p-trifluoromethoxyphenylhydrazone at 15 micromolar inhibited and fusicoccin at 10 micromolar stimulated amino acid uptake. Our data are consistent with a proton-cotransport mechanism for the uptake of l-glutamine and alpha-amino isobutyric acid into soybean mesophyll cells.

  9. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  10. Cell signaling review series

    Institute of Scientific and Technical Information of China (English)

    Aiming Lin; Zhenggang Liu

    2008-01-01

    @@ Signal transduction is pivotal for many, if not all, fundamental cellular functions including proliferation, differentiation, transformation and programmed cell death. Deregulation of cell signaling may result in certain types of cancers and other human diseases.

  11. Stem Cell Transplant

    Science.gov (United States)

    ... transplant is a procedure that infuses healthy blood stem cells into your body to replace your damaged or ... A bone marrow transplant is also called a stem cell transplant. A bone marrow transplant may be necessary ...

  12. Sickle Cell Information Center

    Science.gov (United States)

    ... Nature, Wash Post, SciAm, CNN - Google Custom Search Sickle Cell Anemia News -- ScienceDaily January 18, 1970 Read articles summarizing medical research on sickle-cell anemia. NYT, Nature, Wash Post, SciAm, CNN - Google Custom ...

  13. NIA Aging Cell Repository

    Data.gov (United States)

    Federal Laboratory Consortium — To facilitate aging research on cells in culture, the NIA provides support for the NIA Aging Cell Repository, located at the Coriell Institute for Medical Research...

  14. Stem Cell Basics

    Science.gov (United States)

    ... why are they important? Stem cells have the remarkable potential to develop into many different cell types ... of Health, U.S. Department of Health and Human Services, 2016 [cited October 9, 2017 ] Available at < //stemcells. ...

  15. Sickle Cell Disease

    Science.gov (United States)

    ... About Us Overview of CDC’s work. Advancements in Sickle Cell Disease New supplement from the American Journal of Preventive Medicine describes the state of sickle cell disease related care in the United States. Read Supplement ...

  16. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  17. Engineering Stem Cell Organoids

    National Research Council Canada - National Science Library

    Yin, Xiaolei; Mead, Benjamin E; Safaee, Helia; Langer, Robert; Karp, Jeffrey M; Levy, Oren

    2016-01-01

    .... Herein, we discuss basic approaches to generate stem cell-based organoids, their advantages and limitations, and how bioengineering strategies can be used to steer the cell composition and their 3D...

  18. Giant Cell Arteritis

    Science.gov (United States)

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  19. Odontogenic ghost cell tumour with clear cell components: clear cell odontogenic ghost cell tumour?

    Science.gov (United States)

    Yoon, Jung Hoon; Ahn, Sang Gun; Kim, Su Gwan; Kim, Jin

    2004-07-01

    A case of odontogenic ghost cell tumour (OGCT) with clear cell components was encountered in the mandible of a 63-year-old man. The tumour revealed ameloblastomatous-type epithelial components accompanied by clusters of ghost cells and dentinoid juxtaposed to the odontogenic epithelium. In addition, some areas of the tumour tissue showed sheets and islands of clear, glycogen containing epithelial cells, which were separated by a thin fibrous connective tissue stroma. Both ameloblastic and clear cells exhibited positive immunoreactivities for cytokeratin 19 and AE1/3. It is not known whether this tumour represents a clear cell change of a pre-existing OGCT or a separate and distinct neoplasm derived de novo from the odontogenic epithelium. This tumour was given the term 'clear cell OGCT' because it captures the clear cell components, which is one of the most prominent distinguishing features of the tumour.

  20. Sickle Cell Disease Quiz

    Science.gov (United States)

    ... Websites About Us Information For... Media Policy Makers Sickle Cell Disease Quiz Language: English Español (Spanish) Recommend on ... 1. True or False: Only African Americans get sickle cell disease. A True B False 2. True or ...

  1. Sickle cell anemia.

    OpenAIRE

    ŘÍHOVÁ, Tereza

    2013-01-01

    This thesis is about the disease called sickle cell anemia, or drepanocytosis. In this thesis is described the history of the disease, pathophysiology, laboratory features, various clinical features, diferencial diagnosis, quality of life in sickle cell anemia and therapy.

  2. Cell-SELEX Technology

    Science.gov (United States)

    2012-01-01

    Abstract Aptamers are molecules identified from large combinatorial nucleic acid libraries by their high affinity to target molecules. Due to a variety of desired properties, aptamers are attractive alternatives to antibodies in molecular biology and medical applications. Aptamers are identified through an iterative selection–amplification process known as systematic evolution of ligands by exponential enrichment (SELEX). Although SELEX is typically carried out using purified target molecules, whole live cells are also employable as selection targets. This technology, Cell-SELEX, has several advantages. For example, generated aptamers are functional with a native conformation of the target molecule on live cells, and thus, cell surface transmembrane proteins would be targets even when their purifications in native conformations are difficult. In addition, cell-specific aptamers can be obtained without any knowledge about cell surface molecules on the target cells. Here, I review the progress of Cell-SELEX technology and discuss advantages of the technology. PMID:23515081

  3. White Blood Cell Count

    Science.gov (United States)

    ... limited. Home Visit Global Sites Search Help? White Blood Cell Count Share this page: Was this page helpful? ... Count; Leukocyte Count; White Count Formal name: White Blood Cell Count Related tests: Complete Blood Count , Blood Smear , ...

  4. Mast cell activation disease

    African Journals Online (AJOL)

    EL-HAKIM

    only IgE dependent allergic diseases but also play a ... Mast cells are tissue fixed effector cells of allergic ..... alleviated high intensity symptoms of MCAD.29 ... Osteoporosis, osteolysis, bone pain: biphosphonates (vitamin D plus calcium.

  5. Cell phone explosion.

    Science.gov (United States)

    Atreya, Alok; Kanchan, Tanuj; Nepal, Samata; Pandey, Bhuwan Raj

    2016-03-01

    Cell phone explosions and resultant burn injuries are rarely reported in the scientific literature. We report a case of cell phone explosion that occurred when a young male was listening to music while the mobile was plugged in for charging.

  6. Red blood cell production

    Science.gov (United States)

    ... to one part of the body or another. Red blood cells are an important element of blood. Their job ... is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of ...

  7. Mast cell proteoglycans.

    Science.gov (United States)

    Rönnberg, Elin; Melo, Fabio R; Pejler, Gunnar

    2012-12-01

    Mast cells are versatile effector cells of the immune system, contributing to both innate and adaptive immunity toward pathogens but also having profound detrimental activities in the context of inflammatory disease. A hallmark morphological feature of mast cells is their large content of cytoplasmic secretory granules, filled with numerous secretory compounds, including highly negatively charged heparin or chondroitin sulfate proteoglycans of serglycin type. These anionic proteoglycans provide the basis for the strong metachromatic staining properties of mast cells seen when applying various cationic dyes. Functionally, the mast cell proteoglycans have been shown to have an essential role in promoting the storage of other granule-contained compounds, including bioactive monoamines and different mast cell-specific proteases. Moreover, granule proteoglycans have been shown to regulate the enzymatic activities of mast cell proteases and to promote apoptosis. Here, the current knowledge of mast cell proteoglycans is reviewed.

  8. Diagram of Cell to Cell Communication

    Science.gov (United States)

    2002-01-01

    Diagram depicts the importance of cell-cell communication as central to the understanding of cancer growth and progression, the focus of the NASA bioreactor demonstration system (BDS-05) investigation. Microgravity studies will allow us to unravel the signaling and communication between these cells with the host and potential development of therapies for the treatment of cancer metastasis. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: Emory University.

  9. Diagram of Cell to Cell Communication

    Science.gov (United States)

    2002-01-01

    Diagram depicts the importance of cell-cell communication as central to the understanding of cancer growth and progression, the focus of the NASA bioreactor demonstration system (BDS-05) investigation. Microgravity studies will allow us to unravel the signaling and communication between these cells with the host and potential development of therapies for the treatment of cancer metastasis. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: Emory University.

  10. Increased voltage photovoltaic cell

    Science.gov (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  11. Storage of cell lines.

    Science.gov (United States)

    Parker, Katharine A

    2011-01-01

    The successful storage of cell lines depends upon many factors, including the condition of the cells to be frozen and the experience of the operator. Attempting to freeze down unhealthy, contaminated or poorly labelled cells can have huge implications for a research laboratory. This chapter outlines the importance of good record keeping, vigilant monitoring, aseptic technique, and high-quality reagents in the successful storage and downstream propagation of cell lines.

  12. Skeletal (stromal) stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Kermani, Abbas Jafari; Zaher, Walid

    2015-01-01

    Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy....../preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone....

  13. STEM CELLS AND PROTEOMICS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong-ming; GUO Tian-nan; HUANG Shi-ang

    2006-01-01

    The distinctive features of proteomics are large-scale and high throughput. The key techniques of proteomics are two-dimensional gel electrophoresis, mass spectrometry and bioinformatics. Stem cell can differentiate into all kinds of cells, tissues and organs. There are many proteins and cytokines involved in the process of differentiation. Applying proteomics techniques to the research of the complex process of stem cell differentiation is of great importance to study the mechanism and applications of stem cell differentiation.

  14. Fish stem cell cultures.

    Science.gov (United States)

    Hong, Ni; Li, Zhendong; Hong, Yunhan

    2011-04-13

    Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES) cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on "Fish Stem Cells and Nuclear Transfer", we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  15. Kidney Cell Electrophoresis

    Science.gov (United States)

    Todd, P.

    1985-01-01

    Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated, ground support in the form of analytical cell electrophoresis and flow cytometry was provided and cells returned from space flight were analyzed. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. The protocol established and utilized is given.

  16. Fish Stem Cell Cultures

    Directory of Open Access Journals (Sweden)

    Ni Hong, Zhendong Li, Yunhan Hong

    2011-01-01

    Full Text Available Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on “Fish Stem Cells and Nuclear Transfer”, we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  17. Stem cell heterogeneity revealed

    DEFF Research Database (Denmark)

    Andersen, Marianne S; Jensen, Kim B

    2016-01-01

    The skin forms a protective, water-impermeable barrier consisting of heavily crosslinked epithelial cells. However, the specific role of stem cells in sustaining this barrier remains a contentious issue. A detailed analysis of the interfollicular epidermis now proposes a model for how a composite...... of cells with different properties are involved in its maintenance....

  18. SYNOVIAL CELL SARCOMA

    Directory of Open Access Journals (Sweden)

    M. Farzan

    1997-06-01

    Full Text Available Ten cases of synovial cell sarcoma are reported. The youngest patient was a 2'A years old boy with synovial cell sarcoma of the knee and the oldest one was a man with synovial cell sarcoma of the elbow.

  19. Embryonic Stem Cell Markers

    Directory of Open Access Journals (Sweden)

    Lan Ma

    2012-05-01

    Full Text Available Embryonic stem cell (ESC markers are molecules specifically expressed in ES cells. Understanding of the functions of these markers is critical for characterization and elucidation for the mechanism of ESC pluripotent maintenance and self-renewal, therefore helping to accelerate the clinical application of ES cells. Unfortunately, different cell types can share single or sometimes multiple markers; thus the main obstacle in the clinical application of ESC is to purify ES cells from other types of cells, especially tumor cells. Currently, the marker-based flow cytometry (FCM technique and magnetic cell sorting (MACS are the most effective cell isolating methods, and a detailed maker list will help to initially identify, as well as isolate ESCs using these methods. In the current review, we discuss a wide range of cell surface and generic molecular markers that are indicative of the undifferentiated ESCs. Other types of molecules, such as lectins and peptides, which bind to ESC via affinity and specificity, are also summarized. In addition, we review several markers that overlap with tumor stem cells (TSCs, which suggest that uncertainty still exists regarding the benefits of using these markers alone or in various combinations when identifying and isolating cells.

  20. Advanced Cell Technology, Inc.

    Science.gov (United States)

    Caldwell, William M

    2007-03-01

    Advanced Cell Technology, Inc. (OTCBB: ACTC) is a biotechnology company applying novel human embryonic stem cell technologies in the emerging field of regenerative medicine. We believe that regenerative medicine has the potential to revolutionize the field by enabling scientists to produce human cells of any kind for use in a wide array of therapies.

  1. Nanostructured Organic Solar Cells

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Rubahn, Horst-Günter; Madsen, Morten

    Recent forecasts for alternative energy generation predict emerging importance of supporting state of art photovoltaic solar cells with their organic equivalents. Despite their significantly lower efficiency, number of application niches are suitable for organic solar cells. This work reveals...... the principles of bulk heterojunction organic solar cells fabrication as well as summarises major differences in physics of their operation....

  2. Solar Photovoltaic Cells.

    Science.gov (United States)

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  3. Photoelectrochemical Solar Cells.

    Science.gov (United States)

    McDevitt, John T.

    1984-01-01

    This introduction to photoelectrochemical (PEC) cells reviews topics pertaining to solar energy conversion and demonstrates the ease with which a working PEC cell can be prepared with n-type silicon as the photoanode and a platinum counter electrode (both immersed in ethanolic ferrocene/ferricenium solutions). Experiments using the cell are…

  4. Adventures with Cell Phones

    Science.gov (United States)

    Kolb, Liz

    2011-01-01

    Teachers are finding creative ways to turn the basic cell phone from a digital distraction into a versatile learning tool. In this article, the author explains why cell phones are important in learning and suggests rather than banning them that they be integrated into learning. She presents activities that can be done on a basic cell phone with a…

  5. Cell phones and cancer

    Science.gov (United States)

    Cancer and cell phones; Do cell phones cause cancer? ... Several major studies show no link between cell phones and cancer at this time. However, since the information available is based on short-term studies, the impact of many years of ...

  6. Mammalian Cell Culture Simplified.

    Science.gov (United States)

    Moss, Robert; Solomon, Sondra

    1991-01-01

    A tissue culture experiment that does not require elaborate equipment and that can be used to teach sterile technique, the principles of animal cell line maintenance, and the concept of cell growth curves is described. The differences between cancerous and normal cells can be highlighted. The procedure is included. (KR)

  7. Dazlin' pluripotent stem cells

    NARCIS (Netherlands)

    Welling, M.A.

    2014-01-01

    Pluripotent embryonic stem cells (ESCs) can be isolated from the inner cell mass (ICM) of blastocyst embryos and differentiate into all three germ layers in vitro. However, despite their similar origin, mouse embryonic stem cells represent a more naïve ICM-like pluripotent state whereas human embryo

  8. Cell Culture Made Easy.

    Science.gov (United States)

    Dye, Frank J.

    1985-01-01

    Outlines steps to generate cell samples for observation and experimentation. The procedures (which use ordinary laboratory equipment) will establish a short-term primary culture of normal mammalian cells. Information on culture vessels and cell division and a list of questions to generate student interest and involvement in the topics are…

  9. Solar Photovoltaic Cells.

    Science.gov (United States)

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  10. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...

  11. Aneuploidy in stem cells

    NARCIS (Netherlands)

    Garcia-Martinez, Jorge; Bakker, Bjorn; Schukken, Klaske M; Simon, Judith E; Foijer, Floris

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells (IPSCs) from somatic cells has brought this promise steps closer to real

  12. Border cell release

    DEFF Research Database (Denmark)

    Mravec, Jozef

    2017-01-01

    Plant border cells are specialised cells derived from the root cap with roles in the biomechanics of root growth and in forming a barrier against pathogens. The mechanism of highly localised cell separation which is essential for their release to the environment is little understood. Here I present...

  13. Battery cell module

    Energy Technology Data Exchange (ETDEWEB)

    Shambaugh, J.S.

    1981-11-23

    A modular lithium battery having a plurality of cells, having electrical connecting means connecting the cells to output terminals, and venting means for releasing discharge byproducts to a chemical scrubber is disclosed. Stainless steel cell casings are potted in an aluminum modular case with syntactic foam and epoxy. The wall thickness resulting is about 0.5 inches.

  14. Mouse Leydig Tumor Cells

    Directory of Open Access Journals (Sweden)

    Bo-Syong Pan

    2011-01-01

    Full Text Available Cordycepin is a natural pure compound extracted from Cordyceps sinensis (CS. We have demonstrated that CS stimulates steroidogenesis in primary mouse Leydig cell and activates apoptosis in MA-10 mouse Leydig tumor cells. It is highly possible that cordycepin is the main component in CS modulating Leydig cell functions. Thus, our aim was to investigate the steroidogenic and apoptotic effects with potential mechanism of cordycepin on MA-10 mouse Leydig tumor cells. Results showed that cordycepin significantly stimulated progesterone production in dose- and time-dependent manners. Adenosine receptor (AR subtype agonists were further used to treat MA-10 cells, showing that A1, A 2A , A 2B , and A3, AR agonists could stimulate progesterone production. However, StAR promoter activity and protein expression remained of no difference among all cordycepin treatments, suggesting that cordycepin might activate AR, but not stimulated StAR protein to regulate MA-10 cell steroidogenesis. Meanwhile, cordycepin could also induce apoptotic cell death in MA-10 cells. Moreover, four AR subtype agonists induced cell death in a dose-dependent manner, and four AR subtype antagonists could all rescue cell death under cordycepin treatment in MA-10 cells. In conclusion, cordycepin could activate adenosine subtype receptors and simultaneously induce steroidogenesis and apoptosis in MA-10 mouse Leydig tumor cells.

  15. Molecular Mechanisms of HTLV-1 Cell-to-Cell Transmission

    Directory of Open Access Journals (Sweden)

    Christine Gross

    2016-03-01

    Full Text Available The tumorvirus human T-cell lymphotropic virus type 1 (HTLV-1, a member of the delta-retrovirus family, is transmitted via cell-containing body fluids such as blood products, semen, and breast milk. In vivo, HTLV-1 preferentially infects CD4+ T-cells, and to a lesser extent, CD8+ T-cells, dendritic cells, and monocytes. Efficient infection of CD4+ T-cells requires cell-cell contacts while cell-free virus transmission is inefficient. Two types of cell-cell contacts have been described to be critical for HTLV-1 transmission, tight junctions and cellular conduits. Further, two non-exclusive mechanisms of virus transmission at cell-cell contacts have been proposed: (1 polarized budding of HTLV-1 into synaptic clefts; and (2 cell surface transfer of viral biofilms at virological synapses. In contrast to CD4+ T-cells, dendritic cells can be infected cell-free and, to a greater extent, via viral biofilms in vitro. Cell-to-cell transmission of HTLV-1 requires a coordinated action of steps in the virus infectious cycle with events in the cell-cell adhesion process; therefore, virus propagation from cell-to-cell depends on specific interactions between cellular and viral proteins. Here, we review the molecular mechanisms of HTLV-1 transmission with a focus on the HTLV-1-encoded proteins Tax and p8, their impact on host cell factors mediating cell-cell contacts, cytoskeletal remodeling, and thus, virus propagation.

  16. Cell-ECM traction force modulates endogenous tension at cell-cell contacts.

    Science.gov (United States)

    Maruthamuthu, Venkat; Sabass, Benedikt; Schwarz, Ulrich S; Gardel, Margaret L

    2011-03-22

    Cells in tissues are mechanically coupled both to the ECM and neighboring cells, but the coordination and interdependency of forces sustained at cell-ECM and cell-cell adhesions are unknown. In this paper, we demonstrate that the endogenous force sustained at the cell-cell contact between a pair of epithelial cells is approximately 100 nN, directed perpendicular to the cell-cell interface and concentrated at the contact edges. This force is stably maintained over time despite significant fluctuations in cell-cell contact length and cell morphology. A direct relationship between the total cellular traction force on the ECM and the endogenous cell-cell force exists, indicating that the cell-cell tension is a constant fraction of the cell-ECM traction. Thus, modulation of ECM properties that impact cell-ECM traction alters cell-cell tension. Finally, we show in a minimal model of a tissue that all cells experience similar forces from the surrounding microenvironment, despite differences in the extent of cell-ECM and cell-cell adhesion. This interdependence of cell-cell and cell-ECM forces has significant implications for the maintenance of the mechanical integrity of tissues, mechanotransduction, and tumor mechanobiology.

  17. Visualizing heterogeneity of photosynthetic properties of plant leaves with two-photon fluorescence lifetime imaging microscopy.

    Science.gov (United States)

    Iermak, Ievgeniia; Vink, Jochem; Bader, Arjen N; Wientjes, Emilie; van Amerongen, Herbert

    2016-09-01

    Two-photon fluorescence lifetime imaging microscopy (FLIM) was used to analyse the distribution and properties of Photosystem I (PSI) and Photosystem II (PSII) in palisade and spongy chloroplasts of leaves from the C3 plant Arabidopsis thaliana and the C4 plant Miscanthus x giganteus. This was achieved by separating the time-resolved fluorescence of PSI and PSII in the leaf. It is found that the PSII antenna size is larger on the abaxial side of A. thaliana leaves, presumably because chloroplasts in the spongy mesophyll are "shaded" by the palisade cells. The number of chlorophylls in PSI on the adaxial side of the A. thaliana leaf is slightly higher. The C4 plant M. x giganteus contains both mesophyll and bundle sheath cells, which have a different PSI/PSII ratio. It is shown that the time-resolved fluorescence of bundle sheath and mesophyll cells can be analysed separately. The relative number of chlorophylls, which belong to PSI (as compared to PSII) in the bundle sheath cells is at least 2.5 times higher than in mesophyll cells. FLIM is thus demonstrated to be a useful technique to study the PSI/PSII ratio and PSII antenna size in well-defined regions of plant leaves without having to isolate pigment-protein complexes.

  18. Structure of Kalanchoë pumila Bak. leaves (Crassulaceae DC.

    Directory of Open Access Journals (Sweden)

    Mykhaylo Chernetskyy

    2012-12-01

    Full Text Available The structure of Kalanchoё pumila Bak. was studied with the use of stereoscopic, light, scanning and transmission electron microscopy. It was found that the chlorenchymatic tissue was divided into subepidermal small-celled mesophyll and large-celled (water transporting, CAM type mesophyll, placed in the central part of the leaf. The mesophyll structure and its cell ultrastructure indicate C3 photosynthesis in this taxon, whereas CAM photosynthesis, being an adaptive syndrome, is induced by external factors. Three groups of xeromorphic traits were observed in the structure of K. pumila leaves, related to: 1 storing water in the ground and epidermal tissues, 2 decreased transpiration (the closing of stomata during heat, 3 avoiding excess insolation of the mesophyll and overheating of the leaf (striated cuticula, anthocyan pigments, tannin storage. The last two groups of xeromorphic traits also include thickening of the outer walls of cuticular cells, a thick-layered cuticula, and the presence of epicuticular wax and calcium carbonate deposits. Microchannels which enhance transpiration efficiency in developing K. pumila leaves were found in the vicinity of anticlinal walls in the outer walls of epidermal cells. Calcium deposits produced on the leaf surfaces protect them in extreme conditions. Adaptive traits in the structure of K. pumila leaves are conservative and they confirm the relations between this taxon and the conditions in their native land.

  19. Anatomical changes on coffee leaves infected by Pseudomonas syringae pv. garcae

    Directory of Open Access Journals (Sweden)

    Lucas Mateus Rivero Rodrigues

    2015-12-01

    Full Text Available ABSTRACTAlthough poorly studied, the bacterial halo blight is an important disease in the major coffee-producing states of Brazil. External damage and anatomical changes on leaves were measured in seedlings of Coffea arabica cv. Mundo Novo, susceptible to Pseudomonas syringae pv. garcae, by using histological sections obtained at 10 and 20 days after inoculation (DAI. The changes on the epidermis were smaller than the lesions measured in the mesophyll, irrespective of the evaluated colonization period, showing that the internal damage caused by the bacterium represent twice the damage observed externally. From the inoculation site, lysis occurred on the epidermal cells and on the palisade and spongy parenchyma cells, with strong staining of their cellular contents, as well as abnormal intercellular spaces in the palisade parenchyma, hypertrophy and hyperplasia of mesophyll cells and partial destruction of chloroplasts. Additionally, this study revealed the presence of inclusion bodies in epidermal and mesophyll cells. Bacterial masses were found in the apoplast between and within mesophyll cells. Bacteria were also observed in the bundle sheath and vascular bundles and were more pronounced at 20 DAI, not only near the inoculation site but also in distant areas, suggesting displacement through the vascular system. These results can be useful to understand this plant-pathogen interaction.

  20. Mechanics rules cell biology

    Directory of Open Access Journals (Sweden)

    Wang James HC

    2010-07-01

    Full Text Available Abstract Cells in the musculoskeletal system are subjected to various mechanical forces in vivo. Years of research have shown that these mechanical forces, including tension and compression, greatly influence various cellular functions such as gene expression, cell proliferation and differentiation, and secretion of matrix proteins. Cells also use mechanotransduction mechanisms to convert mechanical signals into a cascade of cellular and molecular events. This mini-review provides an overview of cell mechanobiology to highlight the notion that mechanics, mainly in the form of mechanical forces, dictates cell behaviors in terms of both cellular mechanobiological responses and mechanotransduction.

  1. Transparent ultraviolet photovoltaic cells.

    Science.gov (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  2. Human mesenchymal stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem; Kassem, Moustapha

    2008-01-01

    Mesenchymal stem cells (MSC) are a group of clonogenic cells present among the bone marrow stroma and capable of multilineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. Due to their ease of isolation and their differentiation potential, MSC are being...... introduced into clinical medicine in variety of applications and through different ways of administration. Here, we discuss approaches for isolation, characterization and directing differentiation of human mesenchymal stem cells (hMSC). An update of the current clinical use of the cells is also provided....

  3. Dental pulp stem cells

    DEFF Research Database (Denmark)

    Ashri, N. Y.; Ajlan, S. A.; Aldahmash, Abdullah M.

    2015-01-01

    Inflammatory periodontal disease is a major cause of loss of tooth-supporting structures. Novel approaches for regeneration of periodontal apparatus is an area of intensive research. Periodontal tissue engineering implies the use of appropriate regenerative cells, delivered through a suitable...... scaffold, and guided through signaling molecules. Dental pulp stem cells have been used in an increasing number of studies in dental tissue engineering. Those cells show mesenchymal (stromal) stem cell-like properties including self-renewal and multilineage differentiation potentials, aside from...... an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors....

  4. New cell sources for T cell engineering and adoptive immunotherapy

    National Research Council Canada - National Science Library

    Themeli, Maria; Rivière, Isabelle; Sadelain, Michel

    2015-01-01

    .... Here we review emerging T cell engineering approaches that utilize alternative T cell sources, which include virus-specific or T cell receptor-less allogeneic T cells, expanded lymphoid progenitors...

  5. Fuel Cell/Electrochemical Cell Voltage Monitor

    Science.gov (United States)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  6. Internalization of NK cells into tumor cells requires ezrin and leads to programmed cell-in-cell death

    Institute of Scientific and Technical Information of China (English)

    Shan Wang; Zhen Guo; Peng Xia; Tingting Liu; Jufang Wang; Shan Li; Lihua Sun; Jianxin Lu; Qian Wen; Mingqian Zhou; Li Ma; Xia Ding; Xiaoning Wang; Xuebiao Yao

    2009-01-01

    Cytotoxic lymphocytes are key players in the orchestration of immune response and elimination of defective cells. We have previously reported that natural killer (NK) cells enter target tumor cells, leading to either target cell death or self-destruction within tumor cells. However, it has remained elusive as to the fate of NK cells after internaliza-tion and whether the heterotypic cell-in-cell process is different from that of the homotypic cell-in-cell event recently named entosis. Here, we show that NK cells undergo a cell-in-cell process with the ultimate fate of apoptosis within tumor cells and reveal that the internalization process requires the actin cytoskeletal regulator, ezrin. To visualize how NK cells enter into tumor cells, we carried out real-time dual color imaging analyses of NK cell internalization into tumor cells. Surprisingly, most NK cells commit to programmed cell death after their entry into tumor cells, which is distinctively different from entosis observed in the homotypic cell-in-cell process. The apoptotic cell death of the internalized NK cells was evident by activation of caspase 3 and DNA fragmentation. Furthermore, NK cell death after internalization is attenuated by the caspase inhibitor, Z-VAD-FMK, confirming apoptosis as the mode of NK cell death within tumor cells. To determine protein factors essential for the entry of NK cells into tumor cells, we car-ried out siRNA-based knockdown analysis and discovered a critical role of ezrin in NK cell internalization. Impor-tantly, PKA-mediated phosphorylation of ezrin promotes the NK cell internalization process. Our findings suggest a novel regulatory mechanism by which ezrin governs NK cell internalization into tumor cells.

  7. Islet cell development.

    Science.gov (United States)

    Rojas, Anabel; Khoo, Adrian; Tejedo, Juan R; Bedoya, Francisco J; Soria, Bernat; Martín, Franz

    2010-01-01

    Over the last years, there has been great success in driving stem cells toward insulin-expressing cells. However, the protocols developed to date have some limitations, such as low reliability and low insulin production. The most successful protocols used for generation of insulin-producing cells from stem cells mimic in vitro pancreatic organogenesis by directing the stem cells through stages that resemble several pancreatic developmental stages. Islet cell fate is coordinated by a complex network of inductive signals and regulatory transcription factors that, in a combinatorial way, determine pancreatic organ specification, differentiation, growth, and lineage. Together, these signals and factors direct the progression from multipotent progenitor cells to mature pancreatic cells. Later in development and adult life, several of these factors also contribute to maintain the differentiated phenotype of islet cells. A detailed understanding of the processes that operate in the pancreas during embryogenesis will help us to develop a suitable source of cells for diabetes therapy. In this chapter, we will discuss the main transcription factors involved in pancreas specification and beta-cell formation.

  8. Cell biology. Metabolic control of cell death.

    Science.gov (United States)

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  9. Cell viability assays: introduction.

    Science.gov (United States)

    Stoddart, Martin J

    2011-01-01

    The measurement of cell viability plays a fundamental role in all forms of cell culture. Sometimes it is the main purpose of the experiment, such as in toxicity assays. Alternatively, cell viability can be used to -correlate cell behaviour to cell number, providing a more accurate picture of, for example, anabolic -activity. There are wide arrays of cell viability methods which range from the most routine trypan blue dye exclusion assay to highly complex analysis of individual cells, such as using RAMAN microscopy. The cost, speed, and complexity of equipment required will all play a role in determining the assay used. This chapter aims to provide an overview of many of the assays available today.

  10. Cell Factory Engineering.

    Science.gov (United States)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-03-22

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta-review provides general strategy guides for the broad range of applications of rational engineering of cell factories.

  11. Mammary gland stem cells

    DEFF Research Database (Denmark)

    Fridriksdottir, Agla J R; Petersen, Ole W; Rønnov-Jessen, Lone

    2011-01-01

    Distinct subsets of cells, including cells with stem cell-like properties, have been proposed to exist in normal human breast epithelium and breast carcinomas. The cellular origins of epithelial cells contributing to gland development, tissue homeostasis and cancer are, however, still poorly...... understood. The mouse is a widely used model of mammary gland development, both directly by studying the mouse mammary epithelial cells themselves and indirectly, by studying development, morphogenesis, differentiation and carcinogenesis of xenotransplanted human breast epithelium in vivo. While in early...... studies, human or mouse epithelium was implanted as fragments into the mouse gland, more recent technical progress has allowed the self-renewal capacity and differentiation potential of distinct cell populations or even individual cells to be interrogated. Here, we review and discuss similarities...

  12. Enteroendocrine cell types revisited

    DEFF Research Database (Denmark)

    Engelstoft, Maja S; Egerod, Kristoffer Lihme; Lund, Mari L

    2013-01-01

    The GI-tract is profoundly involved in the control of metabolism through peptide hormones secreted from enteroendocrine cells scattered throughout the gut mucosa. A large number of recently generated transgenic reporter mice have allowed for direct characterization of biochemical and cell...... biological properties of these previously highly elusive enteroendocrine cells. In particular the surprisingly broad co-expression of six functionally related hormones in the intestinal enteroendocrine cells indicates that it should be possible to control not only the hormone secretion but also the type...... and number of enteroendocrine cells. However, this will require a more deep understanding of the factors controlling differentiation, gene expression and specification of the enteroendocrine cells during their weekly renewal from progenitor cells in the crypts of the mucosa....

  13. Peripheral giant cell granuloma

    Directory of Open Access Journals (Sweden)

    Padam Narayan Tandon

    2012-01-01

    Full Text Available Peripheral giant cell granuloma or the so-called "giant cell epulis" is the most common oral giant cell lesion. It normally presents as a soft tissue purplish-red nodule consisting of multinucleated giant cells in a background of mononuclear stromal cells and extravasated red blood cells. This lesion probably does not represent a true neoplasm, but rather may be reactive in nature, believed to be stimulated by local irritation or trauma, but the cause is not certainly known. This article reports a case of peripheral giant cell granuloma arising at the maxillary anterior region in a 22-year-old female patient. The lesion was completely excised to the periosteum level and there is no residual or recurrent swelling or bony defect apparent in the area of biopsy after a follow-up period of 6 months.

  14. Cell and Tissue Engineering

    CERN Document Server

    2012-01-01

    Cell and Tissue Engineering” introduces the principles and new approaches in cell and tissue engineering. It includes both the fundamentals and the current trends in cell and tissue engineering, in a way useful both to a novice and an expert in the field. The book is composed of 13 chapters all of which are written by the leading experts. It is organized to gradually assemble an insight in cell and tissue function starting form a molecular nano-level, extending to a cellular micro-level and finishing at the tissue macro-level. In specific, biological, physiological, biophysical, biochemical, medical, and engineering aspects are covered from the standpoint of the development of functional substitutes of biological tissues for potential clinical use. Topics in the area of cell engineering include cell membrane biophysics, structure and function of the cytoskeleton, cell-extracellular matrix interactions, and mechanotransduction. In the area of tissue engineering the focus is on the in vitro cultivation of ...

  15. Human regulatory B cells control the TFH cell response.

    Science.gov (United States)

    Achour, Achouak; Simon, Quentin; Mohr, Audrey; Séité, Jean-François; Youinou, Pierre; Bendaoud, Boutahar; Ghedira, Ibtissem; Pers, Jacques-Olivier; Jamin, Christophe

    2017-07-01

    Follicular helper T (TFH) cells support terminal B-cell differentiation. Human regulatory B (Breg) cells modulate cellular responses, but their control of TFH cell-dependent humoral immune responses is unknown. We sought to assess the role of Breg cells on TFH cell development and function. Human T cells were polyclonally stimulated in the presence of IL-12 and IL-21 to generate TFH cells. They were cocultured with B cells to induce their terminal differentiation. Breg cells were included in these cultures, and their effects were evaluated by using flow cytometry and ELISA. B-cell lymphoma 6, IL-21, inducible costimulator, CXCR5, and programmed cell death protein 1 (PD-1) expressions increased on stimulated human T cells, characterizing TFH cell maturation. In cocultures they differentiated B cells into CD138(+) plasma and IgD(-)CD27(+) memory cells and triggered immunoglobulin secretions. Breg cells obtained by Toll-like receptor 9 and CD40 activation of B cells prevented TFH cell development. Added to TFH cell and B-cell cocultures, they inhibited B-cell differentiation, impeded immunoglobulin secretions, and expanded Foxp3(+)CXCR5(+)PD-1(+) follicular regulatory T cells. Breg cells modulated IL-21 receptor expressions on TFH cells and B cells, and their suppressive activities involved CD40, CD80, CD86, and intercellular adhesion molecule interactions and required production of IL-10 and TGF-β. Human Breg cells control TFH cell maturation, expand follicular regulatory T cells, and inhibit the TFH cell-mediated antibody secretion. These novel observations demonstrate a role for the Breg cell in germinal center reactions and suggest that deficient activities might impair the TFH cell-dependent control of humoral immunity and might lead to the development of aberrant autoimmune responses. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  16. Phloem loading in two Scrophulariaceae species. What can drive symplastic flow via plasmodesmata?

    Science.gov (United States)

    Voitsekhovskaja, Olga V; Koroleva, Olga A; Batashev, Denis R; Knop, Christian; Tomos, A Deri; Gamalei, Yuri V; Heldt, Hans-Walter; Lohaus, Gertrud

    2006-01-01

    To determine the driving forces for symplastic sugar flux between mesophyll and phloem, gradients of sugar concentrations and osmotic pressure were studied in leaf tissues of two Scrophulariaceae species, Alonsoa meridionalis and Asarina barclaiana. A. meridionalis has a typical symplastic configuration of minor-vein phloem, i.e. intermediary companion cells with highly developed plasmodesmal connections to bundle-sheath cells. In A. barclaiana, two types of companion cells, modified intermediary cells and transfer cells, were found in minor-vein phloem, giving this species the potential to have a complex phloem-loading mode. We identified all phloem-transported carbohydrates in both species and analyzed the levels of carbohydrates in chloroplasts, vacuoles, and cytoplasm of mesophyll cells by nonaqueous fractionation. Osmotic pressure was measured in single epidermal and mesophyll cells and in whole leaves and compared with calculated values for phloem sap. In A. meridionalis, a 2-fold concentration gradient for sucrose between mesophyll and phloem was found. In A. barclaiana, the major transported carbohydrates, sucrose and antirrhinoside, were present in the phloem in 22- and 6-fold higher concentrations, respectively, than in the cytoplasm of mesophyll cells. The data show that diffusion of sugars along their concentration gradients is unlikely to be the major mechanism for symplastic phloem loading if this were to occur in these species. We conclude that in both A. meridionalis and A. barclaiana, apoplastic phloem loading is an indispensable mechanism and that symplastic entrance of solutes into the phloem may occur by mass flow. The conditions favoring symplastic mass flow into the phloem are discussed.

  17. Phloem Loading in Two Scrophulariaceae Species. What Can Drive Symplastic Flow via Plasmodesmata?1

    Science.gov (United States)

    Voitsekhovskaja, Olga V.; Koroleva, Olga A.; Batashev, Denis R.; Knop, Christian; Tomos, A. Deri; Gamalei, Yuri V.; Heldt, Hans-Walter; Lohaus, Gertrud

    2006-01-01

    To determine the driving forces for symplastic sugar flux between mesophyll and phloem, gradients of sugar concentrations and osmotic pressure were studied in leaf tissues of two Scrophulariaceae species, Alonsoa meridionalis and Asarina barclaiana. A. meridionalis has a typical symplastic configuration of minor-vein phloem, i.e. intermediary companion cells with highly developed plasmodesmal connections to bundle-sheath cells. In A. barclaiana, two types of companion cells, modified intermediary cells and transfer cells, were found in minor-vein phloem, giving this species the potential to have a complex phloem-loading mode. We identified all phloem-transported carbohydrates in both species and analyzed the levels of carbohydrates in chloroplasts, vacuoles, and cytoplasm of mesophyll cells by nonaqueous fractionation. Osmotic pressure was measured in single epidermal and mesophyll cells and in whole leaves and compared with calculated values for phloem sap. In A. meridionalis, a 2-fold concentration gradient for sucrose between mesophyll and phloem was found. In A. barclaiana, the major transported carbohydrates, sucrose and antirrhinoside, were present in the phloem in 22- and 6-fold higher concentrations, respectively, than in the cytoplasm of mesophyll cells. The data show that diffusion of sugars along their concentration gradients is unlikely to be the major mechanism for symplastic phloem loading if this were to occur in these species. We conclude that in both A. meridionalis and A. barclaiana, apoplastic phloem loading is an indispensable mechanism and that symplastic entrance of solutes into the phloem may occur by mass flow. The conditions favoring symplastic mass flow into the phloem are discussed. PMID:16377750

  18. Involvement of plant stem cells or stem cell-like cells in dedifferentiation

    Directory of Open Access Journals (Sweden)

    Fangwei eJiang

    2015-11-01

    Full Text Available Dedifferentiation is the transformation of cells from a given differentiated state to a less differentiated or stem cell-like state. Stem cell-related genes play important roles in dedifferentiation, which exhibits similar histone modification and DNA methylation features to stem cell maintenance. Hence, stem cell-related factors possibly synergistically function to provide a specific niche beneficial to dedifferentiation. During callus formation in Arabidopsis petioles, cells adjacent to procambium cells (stem cell-like cells are dedifferentiated and survive more easily than other cell types. This finding indicates that stem cells or stem cell-like cells may influence the dedifferentiating niche. In this paper, we provide a brief overview of stem cell maintenance and dedifferentiation regulation. We also summarize current knowledge of genetic and epigenetic mechanisms underlying the balance between differentiation and dedifferentiation. Furthermore, we discuss the correlation of stem cells or stem cell-like cells with dedifferentiation.

  19. Stages of Renal Cell Cancer

    Science.gov (United States)

    ... cell cancer is a disease in which malignant (cancer) cells form in tubules of the kidney. Renal cell ... diagnosed, tests are done to find out if cancer cells have spread within the kidney or to other ...

  20. Membrane Cells for Brine Electrolysis.

    Science.gov (United States)

    Tingle, M.

    1982-01-01

    Membrane cells were developed as alternatives to mercury and diaphragm cells for the electrolysis of brine. Compares the three types of cells, focusing on the advantages and disadvantages of membrane cells. (JN)

  1. Membrane Cells for Brine Electrolysis.

    Science.gov (United States)

    Tingle, M.

    1982-01-01

    Membrane cells were developed as alternatives to mercury and diaphragm cells for the electrolysis of brine. Compares the three types of cells, focusing on the advantages and disadvantages of membrane cells. (JN)

  2. High Red Blood Cell Count

    Science.gov (United States)

    Symptoms High red blood cell count By Mayo Clinic Staff A high red blood cell count is an increase in oxygen-carrying cells in your bloodstream. Red blood cells transport oxygen from your lungs to tissues throughout ...

  3. Cutaneous hamartoma with pagetoid cells.

    Science.gov (United States)

    Piérard-Franchimont, C; Dosal, F L; Estrada, J A; Piérard, G E

    1991-04-01

    We report an unusual cutaneous hamartoma with pagetoid cells characterized by the presence of intraepidermal cells resembling Toker's cells of the nipple. These cells were EMA positive and could be related to the histogenesis of some Paget's disease.

  4. Cell to substratum and cell to cell interactions of microalgae.

    Science.gov (United States)

    Ozkan, Altan; Berberoglu, Halil

    2013-12-01

    This paper reports the cell to substratum and cell to cell interactions of a diverse group of microalgae based on the Extended Derjaguin, Landau, Verwey, Overbeek (XDLVO) approach using the previously reported physico-chemical surface properties. The microalgae included 10 different species of green algae and diatoms from both freshwater and saltwater environments while the substrata included glass, indium-tin oxide (ITO), stainless steel, polycarbonate, polyethylene, and polystryrene. The results indicated that acid-base interactions were the dominating mechanism of interaction for microalgae. For green algae, if at least one of the interacting surfaces was hydrophobic, adhesion at primary minimum was predicted without any energy barrier. However, most diatom systems featured energy barriers for adhesion due to repulsive van der Waals interactions. The results reported in this study are expected to provide useful data and insight into the interaction mechanisms of microalgae cells with each other and with substrata for a number of practical applications including prevention of biofouling of photobioreactors and other man-made surfaces, promotion of biofilm formation in algal biofilm photobioreactors, and developing bioflocculation strategies for energy efficient harvesting of algal biomass. Particularly, Botryococcus braunii and Cerithiopsis fusiformis were identified as promising species for biofloccuation and biofilm formation in freshwater and saltwater aquatic systems, respectively. Finally, based on the observed trends in this study, use of hydrophilic algae and hydrophilic coatings over surfaces are recommended for minimizing biofouling in aquatic systems.

  5. PEROVSKITE SOLAR CELLS (REVIEW ARTICLE)

    OpenAIRE

    Benli, Deniz Ahmet

    2015-01-01

    A solar cell is a device that converts sunlight into electricity. There are different types of solar cells but this report mainly focuses on a type of new generation solar cell that has the name organo-metal halide perovskite, shortly perovskite solar cells. In this respect, the efficiency of power conversion is taken into account to replace the dominancy of traditional and second generation solar cell fields by perovskite solar cells. Perovskite solar cell is a type of solar cell including a...

  6. Cell-to-cell transmission can overcome multiple donor and target cell barriers imposed on cell-free HIV.

    Science.gov (United States)

    Zhong, Peng; Agosto, Luis M; Ilinskaya, Anna; Dorjbal, Batsukh; Truong, Rosaline; Derse, David; Uchil, Pradeep D; Heidecker, Gisela; Mothes, Walther

    2013-01-01

    Virus transmission can occur either by a cell-free mode through the extracellular space or by cell-to-cell transmission involving direct cell-to-cell contact. The factors that determine whether a virus spreads by either pathway are poorly understood. Here, we assessed the relative contribution of cell-free and cell-to-cell transmission to the spreading of the human immunodeficiency virus (HIV). We demonstrate that HIV can spread by a cell-free pathway if all the steps of the viral replication cycle are efficiently supported in highly permissive cells. However, when the cell-free path was systematically hindered at various steps, HIV transmission became contact-dependent. Cell-to-cell transmission overcame barriers introduced in the donor cell at the level of gene expression and surface retention by the restriction factor tetherin. Moreover, neutralizing antibodies that efficiently inhibit cell-free HIV were less effective against cell-to-cell transmitted virus. HIV cell-to-cell transmission also efficiently infected target T cells that were relatively poorly susceptible to cell-free HIV. Importantly, we demonstrate that the donor and target cell types influence critically the extent by which cell-to-cell transmission can overcome each barrier. Mechanistically, cell-to-cell transmission promoted HIV spread to more cells and infected target cells with a higher proviral content than observed for cell-free virus. Our data demonstrate that the frequently observed contact-dependent spread of HIV is the result of specific features in donor and target cell types, thus offering an explanation for conflicting reports on the extent of cell-to-cell transmission of HIV.

  7. Cell-to-cell transmission can overcome multiple donor and target cell barriers imposed on cell-free HIV.

    Directory of Open Access Journals (Sweden)

    Peng Zhong

    Full Text Available Virus transmission can occur either by a cell-free mode through the extracellular space or by cell-to-cell transmission involving direct cell-to-cell contact. The factors that determine whether a virus spreads by either pathway are poorly understood. Here, we assessed the relative contribution of cell-free and cell-to-cell transmission to the spreading of the human immunodeficiency virus (HIV. We demonstrate that HIV can spread by a cell-free pathway if all the steps of the viral replication cycle are efficiently supported in highly permissive cells. However, when the cell-free path was systematically hindered at various steps, HIV transmission became contact-dependent. Cell-to-cell transmission overcame barriers introduced in the donor cell at the level of gene expression and surface retention by the restriction factor tetherin. Moreover, neutralizing antibodies that efficiently inhibit cell-free HIV were less effective against cell-to-cell transmitted virus. HIV cell-to-cell transmission also efficiently infected target T cells that were relatively poorly susceptible to cell-free HIV. Importantly, we demonstrate that the donor and target cell types influence critically the extent by which cell-to-cell transmission can overcome each barrier. Mechanistically, cell-to-cell transmission promoted HIV spread to more cells and infected target cells with a higher proviral content than observed for cell-free virus. Our data demonstrate that the frequently observed contact-dependent spread of HIV is the result of specific features in donor and target cell types, thus offering an explanation for conflicting reports on the extent of cell-to-cell transmission of HIV.

  8. Nanofluidic fuel cell

    Science.gov (United States)

    Lee, Jin Wook; Kjeang, Erik

    2013-11-01

    Fuel cells are gaining momentum as a critical component in the renewable energy mix for stationary, transportation, and portable power applications. State-of-the-art fuel cell technology benefits greatly from nanotechnology applied to nanostructured membranes, catalysts, and electrodes. However, the potential of utilizing nanofluidics for fuel cells has not yet been explored, despite the significant opportunity of harnessing rapid nanoscale reactant transport in close proximity to the reactive sites. In the present article, a nanofluidic fuel cell that utilizes fluid flow through nanoporous media is conceptualized and demonstrated for the first time. This transformative concept captures the advantages of recently developed membraneless and catalyst-free fuel cell architectures paired with the enhanced interfacial contact area enabled by nanofluidics. When compared to previously reported microfluidic fuel cells, the prototype nanofluidic fuel cell demonstrates increased surface area, reduced activation overpotential, superior kinetic characteristics, and moderately enhanced fuel cell performance in the high cell voltage regime with up to 14% higher power density. However, the expected mass transport benefits in the high current density regime were constrained by high ohmic cell resistance, which could likely be resolved through future optimization studies.

  9. Biology of Schwann cells.

    Science.gov (United States)

    Kidd, Grahame J; Ohno, Nobuhiko; Trapp, Bruce D

    2013-01-01

    The fundamental roles of Schwann cells during peripheral nerve formation and regeneration have been recognized for more than 100 years, but the cellular and molecular mechanisms that integrate Schwann cell and axonal functions continue to be elucidated. Derived from the embryonic neural crest, Schwann cells differentiate into myelinating cells or bundle multiple unmyelinated axons into Remak fibers. Axons dictate which differentiation path Schwann cells follow, and recent studies have established that axonal neuregulin1 signaling via ErbB2/B3 receptors on Schwann cells is essential for Schwann cell myelination. Extracellular matrix production and interactions mediated by specific integrin and dystroglycan complexes are also critical requisites for Schwann cell-axon interactions. Myelination entails expansion and specialization of the Schwann cell plasma membrane over millimeter distances. Many of the myelin-specific proteins have been identified, and transgenic manipulation of myelin genes have provided novel insights into myelin protein function, including maintenance of axonal integrity and survival. Cellular events that facilitate myelination, including microtubule-based protein and mRNA targeting, and actin based locomotion, have also begun to be understood. Arguably, the most remarkable facet of Schwann cell biology, however, is their vigorous response to axonal damage. Degradation of myelin, dedifferentiation, division, production of axonotrophic factors, and remyelination all underpin the substantial regenerative capacity of the Schwann cells and peripheral nerves. Many of these properties are not shared by CNS fibers, which are myelinated by oligodendrocytes. Dissecting the molecular mechanisms responsible for the complex biology of Schwann cells continues to have practical benefits in identifying novel therapeutic targets not only for Schwann cell-specific diseases but other disorders in which axons degenerate. Copyright © 2013 Elsevier B.V. All rights

  10. The Chlamydomonas cell cycle.

    Science.gov (United States)

    Cross, Frederick R; Umen, James G

    2015-05-01

    The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants; and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that has been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell division, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth and the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole-basal body-flagellar cycle. Here, we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell-cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell-cycle control, compared with this model. We next review the cytology and cell biology of the multiple-fission cell cycle of Chlamydomonas. Lastly, we review recent genetic approaches and insights into Chlamydomonas cell-cycle regulation that have been enabled by a new generation of genomics-based tools. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

  11. Reference: 386 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 386 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16698900i Hricová Andrea...d mesophyll cell proliferation in Arabidopsis. 3 942-56 16698900 2006 Jul Plant physiology Hricová Andrea|Micol José Luis|Quesada Victor

  12. Biology of Leptoypha hospita (Hemiptera: Tingidae), a Potential Biological Control Agent of Chinese Privet

    Science.gov (United States)

    Yanzhuo Zhang; James L. Hanula; Scott Horn; Kristine Braman; Jianghua Sun

    2011-01-01

    The biology of Leptoypha hospita Drake et Poor (Hemiptera: Tingidae), a potential biological control agent from China for Chinese privet, Ligustrum sinense Lour., was studied in quarantine in the United States. Both nymphs and adults feed on Chinese privet mesophyll cells that lead to a bleached appearance of leaves and dieback of branch tips. L. hospita has five...

  13. Interactions of C4 subtype metabolic activities and transport in maize are revealed through the characterization of DCT2 mutants

    Science.gov (United States)

    C4 photosynthesis is an elaborate set of metabolic pathways that utilize specialized anatomical and biochemical adaptations to concentrate CO2 around RuBisCO. The activities of the C4 pathways are coordinated between two specialized leaf cell types, mesophyll (M) and bundle sheath (BS), and rely hea...

  14. Non-linear direct effects of acid rain on leaf photosynthetic rate of terrestrial plants

    NARCIS (Netherlands)

    Dong, Dan; Du, Enzai; Sun, Zhengzhong; Zeng, Xuetong; Vries, de Wim

    2017-01-01

    Anthropogenic emissions of acid precursors have enhanced global occurrence of acid rain, especially in East Asia. Acid rain directly suppresses leaf function by eroding surface waxes and cuticle and leaching base cations from mesophyll cells, while the simultaneous foliar uptake of nitrates in

  15. Cell-Substrate Adhesion by Amoeboid Cells

    Science.gov (United States)

    Flanders, Bret; Panta, Krishna

    Amoeboid migration is a rapid (10 μm min-1) mode of migration that some tumor cells exhibit. To permit such rapid movement, the adhesive contacts between the cell and the substrate must be relatively short-lived and weak. In this study, we investigate the basic adhesive character of amoeboid cells (D. discoideum) in contact with silanized glass substrates. We observe the initiation and spreading of the adhesive contacts that these cells establish as they settle under gravity onto the substrate and relax towards mechanical equilibrium. The use of interference reflection microscopy and cellular tethering measurements have allowed us to determine the basic adhesive properties of the cell: the membrane-medium interfacial energy; the bending modulus; the equilibrium contact angle; and the work of adhesion. We find the time scale on which settling occurs to be longer than expected. Implications of these results on adhesion and migration will be discussed. The authors are grateful for support from NSF (CBET-1451903) and NIH (1R21EY026392).

  16. Isolation of rare cancer cells from blood cells using dielectrophoresis.

    Science.gov (United States)

    Salmanzadeh, Alireza; Sano, Michael B; Shafiee, Hadi; Stremler, Mark A; Davalos, Rafael V

    2012-01-01

    In this study, we investigate the application of contactless dielectrophoresis (cDEP) for isolating cancer cells from blood cells. Devices with throughput of 0.2 mL/hr (equivalent to sorting 3×10(6) cells per minute) were used to trap breast cancer cells while allowing blood cells through. We have shown that this technique is able to isolate cancer cells in concentration as low as 1 cancer cell per 10(6) hematologic cells (equivalent to 1000 cancer cells in 1 mL of blood). We achieved 96% trapping of the cancer cells at 600 kHz and 300 V(RMS).

  17. Embryonic stem cell-somatic cell fusion and postfusion enucleation.

    Science.gov (United States)

    Sumer, Huseyin; Verma, Paul J

    2015-01-01

    Embryonic stem (ES) cells are able to reprogram somatic cells following cell fusion. The resulting cell hybrids have been shown to have similar properties to pluripotent cells. It has also been shown that transcriptional changes can occur in a heterokaryon, without nuclear hybridization. However it is unclear whether these changes can be sustained following removal of the dominant ES nucleus. In this chapter, methods are described for the cell fusion of mouse tetraploid ES cells with somatic cells and enrichment of the resulting heterokaryons. We next describe the conditions for the differential removal of the ES cell nucleus, allowing for the recovery of somatic cells.

  18. New Cell Sources for T Cell Engineering and Adoptive Immunotherapy

    Science.gov (United States)

    Themeli, Maria; Rivière, Isabelle; Sadelain, Michel

    2017-01-01

    The promising clinical results obtained with engineered T cells, including chimeric antigen receptor (CAR) therapy, call for further advancements to facilitate and broaden their applicability. One potentially beneficial innovation is to exploit new T cell sources that reduce the need for autologous cell manufacturing and enable cell transfer across histocompatibility barriers. Here we review emerging T cell engineering approaches that utilize alternative T cell sources, which include virus-specific or T cell receptor-less allogeneic T cells, expanded lymphoid progenitors, and induced pluripotent stem cell (iPSC)-derived T lymphocytes. The latter offer the prospect for true off-the-shelf, genetically enhanced, histocompatible cell therapy products. PMID:25842976

  19. Myoepithelial cells in pathology

    Directory of Open Access Journals (Sweden)

    N Balachander

    2015-01-01

    Full Text Available Myoepithelial cells are a normal constituent of the salivary acini and ducts and are found between the epithelial cells and the basement membrane. Microscopically myoepithelial cells are thin and spindle-shaped and ultrastructurally they possess a number of Cytoplasmic processes that extend between and over the acinar and ductal-lining cells, and they show features of both smooth muscle and epithelium. They play a vital role during expulsion of saliva and regulates the electrolytic exchange. They also perform as tumor suppressors and are considered to play a very important role in differentiation of various salivary gland tumors and help in the diagnosis of tumors. Neoplastic myoepithelial cells in both benign and malignant tumors can take numerous forms including epithelioid, plasmacytoid, spindle and clear cell variant, and this variability largely accounts for difficulties in histopathological diagnosis.

  20. Melanoma stem cells.

    Science.gov (United States)

    Roesch, Alexander

    2015-02-01

    The cancer stem cell concept significantly broadens our understanding of melanoma biology. However, this concept should be regarded as an integral part of a holistic cancer model that also includes the genetic evolution of tumor cells and the variability of cell phenotypes within a dynamic tumor microenvironment. The biologic complexity and methodological difficulties in identifying cancer stem cells and their biomarkers are currently impeding the direct translation of experimental findings into clinical practice. Nevertheless, it is these methodological shortcomings that provide a new perspective on the phenotypic heterogeneity and plasticity of melanoma with important consequences for future therapies. The development of new combination treatment strategies, particularly with regard to overcoming treatment resistance, could significantly benefit from targeted elimination of cell subpopulations with cancer stem cell properties. © 2015 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  1. Gingival plasma cell granuloma

    Directory of Open Access Journals (Sweden)

    Amitkumar B Pandav

    2012-01-01

    Full Text Available Plasma cell granuloma, also known as inflammatory pseudotumor is a tumor-like lesion that manifests primarily in the lungs. But it may occur in various other anatomic locations like orbit, head and neck, liver and rarely in the oral cavity. We here report an exceedingly rare case of gingival plasma cell granuloma in a 58 year old woman who presented with upper gingival polypoidal growth. The histopathological examination revealed a mass composed of proliferation of benign spindle mesenchymal cells in a loose myxoid and fibrocollagenous stroma along with dense infiltrate of chronic inflammatory cells predominantly containing plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma.

  2. Regulatory T cell memory

    Science.gov (United States)

    Rosenblum, Michael D.; Way, Sing Sing; Abbas, Abul K.

    2016-01-01

    Memory for antigen is a defining feature of adaptive immunity. Antigen-specific lymphocyte populations show an increase in number and function after antigen encounter and more rapidly re-expand upon subsequent antigen exposure. Studies of immune memory have primarily focused on effector B cells and T cells with microbial specificity, using prime challenge models of infection. However, recent work has also identified persistently expanded populations of antigen-specific regulatory T cells that protect against aberrant immune responses. In this Review, we consider the parallels between memory effector T cells and memory regulatory T cells, along with the functional implications of regulatory memory in autoimmunity, antimicrobial host defence and maternal fetal tolerance. In addition, we discuss emerging evidence for regulatory T cell memory in humans and key unanswered questions in this rapidly evolving field. PMID:26688349

  3. Trafficking and cell migration.

    Science.gov (United States)

    Ulrich, Florian; Heisenberg, Carl-Philipp

    2009-07-01

    The migration of single cells and epithelial sheets is of great importance for gastrulation and organ formation in developing embryos and, if misregulated, can have dire consequences e.g. during cancer metastasis. A keystone of cell migration is the regulation of adhesive contacts, which are dynamically assembled and disassembled via endocytosis. Here, we discuss some of the basic concepts about the function of endocytic trafficking during cell migration: transport of integrins from the cell rear to the leading edge in fibroblasts; confinement of signalling to the front of single cells by endocytic transport of growth factors; regulation of movement coherence in multicellular sheets by cadherin turnover; and shaping of extracellular chemokine gradients. Taken together, endocytosis enables migrating cells and tissues to dynamically modulate their adhesion and signalling, allowing them to efficiently migrate through their extracellular environment.

  4. Cell Factory Engineering

    DEFF Research Database (Denmark)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely...... focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies...... in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta...

  5. NCAM regulates cell motility

    DEFF Research Database (Denmark)

    Prag, Søren; Lepekhin, Eugene A; Kolkova, Kateryna

    2002-01-01

    Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma cells...... independently of homophilic NCAM interactions. Expression of the transmembrane 140 kDa isoform of NCAM (NCAM-140) caused a significant reduction in cellular motility, probably through interference with factors regulating cellular attachment, as NCAM-140-expressing cells exhibited a decreased attachment...... to a fibronectin substratum compared with NCAM-negative cells. Ectopic expression of the cytoplasmic part of NCAM-140 also inhibited cell motility, presumably via the non-receptor tyrosine kinase p59(fyn) with which NCAM-140 interacts. Furthermore, we showed that the extracellular part of NCAM acted as a paracrine...

  6. Cytoskeleton and Cell Motility

    CERN Document Server

    Risler, Thomas

    2011-01-01

    The present article is an invited contribution to the Encyclopedia of Complexity and System Science, Robert A. Meyers Ed., Springer New York (2009). It is a review of the biophysical mechanisms that underly cell motility. It mainly focuses on the eukaryotic cytoskeleton and cell-motility mechanisms. Bacterial motility as well as the composition of the prokaryotic cytoskeleton is only briefly mentioned. The article is organized as follows. In Section III, I first present an overview of the diversity of cellular motility mechanisms, which might at first glance be categorized into two different types of behaviors, namely "swimming" and "crawling". Intracellular transport, mitosis - or cell division - as well as other extensions of cell motility that rely on the same essential machinery are briefly sketched. In Section IV, I introduce the molecular machinery that underlies cell motility - the cytoskeleton - as well as its interactions with the external environment of the cell and its main regulatory pathways. Sec...

  7. Myoepithelial cells in pathology.

    Science.gov (United States)

    Balachander, N; Masthan, K M K; Babu, N Aravindha; Anbazhagan, V

    2015-04-01

    Myoepithelial cells are a normal constituent of the salivary acini and ducts and are found between the epithelial cells and the basement membrane. Microscopically myoepithelial cells are thin and spindle-shaped and ultrastructurally they possess a number of Cytoplasmic processes that extend between and over the acinar and ductal-lining cells, and they show features of both smooth muscle and epithelium. They play a vital role during expulsion of saliva and regulates the electrolytic exchange. They also perform as tumor suppressors and are considered to play a very important role in differentiation of various salivary gland tumors and help in the diagnosis of tumors. Neoplastic myoepithelial cells in both benign and malignant tumors can take numerous forms including epithelioid, plasmacytoid, spindle and clear cell variant, and this variability largely accounts for difficulties in histopathological diagnosis.

  8. Aneuploidy in stem cells

    Institute of Scientific and Technical Information of China (English)

    Jorge; Garcia-Martinez; Bjorn; Bakker; Klaske; M; Schukken; Judith; E; Simon; Floris; Foijer

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells(IPSCs) from somatic cells has brought this promise steps closer to reality. However,as somatic cells might have accumulated various chromosomal abnormalities,including aneuploidies throughout their lives,the resulting IPSCs might no longer carry the perfect blueprint for the tissue to be generated,or worse,become at risk of adopting a malignant fate. In this review,we discuss the contribution of aneuploidy to healthy tissues and how aneuploidy can lead to disease. Furthermore,we review the differences between how somatic cells and stem cells respond to aneuploidy.

  9. Mechanical plasticity of cells

    Science.gov (United States)

    Bonakdar, Navid; Gerum, Richard; Kuhn, Michael; Spörrer, Marina; Lippert, Anna; Schneider, Werner; Aifantis, Katerina E.; Fabry, Ben

    2016-10-01

    Under mechanical loading, most living cells show a viscoelastic deformation that follows a power law in time. After removal of the mechanical load, the cell shape recovers only incompletely to its original undeformed configuration. Here, we show that incomplete shape recovery is due to an additive plastic deformation that displays the same power-law dynamics as the fully reversible viscoelastic deformation response. Moreover, the plastic deformation is a constant fraction of the total cell deformation and originates from bond ruptures within the cytoskeleton. A simple extension of the prevailing viscoelastic power-law response theory with a plastic element correctly predicts the cell behaviour under cyclic loading. Our findings show that plastic energy dissipation during cell deformation is tightly linked to elastic cytoskeletal stresses, which suggests the existence of an adaptive mechanism that protects the cell against mechanical damage.

  10. Induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    Siddhartha Bhowmik; LI Yong

    2011-01-01

    Induced pluripotent stem (iPS) cells are a recent development which has brought a promise of great therapeutic values. The previous technique of somatic cell nuclear transfer (SCNT) has been ineffective in humans. Recent discoveries show that human fibroblasts can be reprogrammed by a transient over expression of a small number of genes; they can undergo induced pluripotency. iPS were first produced in 2006. By 2008, work was underway to remove the potential oncogenes from their structure. In 2009, protein iPS (piPS) cells were discovered. Surface markers and reporter genes play an important role in stem cell research. Clinical applications include generation of self renewing stem cells, tissue replacement and many more. Stem cell therapy has the ability to dramatically change the treatment of human diseases.

  11. Fish germ cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Fish, like many other animals, have two major cell lineages, namely the germline and soma. The germ-soma separation is one of the earliest events of embryonic development. Germ cells can be specifically labeled and isolated for culture and transplan-tation, providing tools for reproduction of endangered species in close relatives, such as surrogate production of trout in salmon. Haploid cell cultures, such as medaka haploid embryonic stem cells have recently been obtained, which are capable of mimicking sperm to produce fertile offspring, upon nuclear being directly transferred into normal eggs. Such fish originated from a mosaic oocyte that had a haploid meiotic nucleus and a transplanted haploid mitotic cell culture nucleus. The first semi-cloned fish is Holly. Here we review the current status and future directions of understanding and manipulating fish germ cells in basic research and reproductive technology.

  12. Gingival plasma cell granuloma

    Directory of Open Access Journals (Sweden)

    Phadnaik Mangesh

    2010-01-01

    Full Text Available Plasma cell granuloma is a rare reactive lesion composed of polyclonal plasma cells. It manifests primarily in the lungs, but may occur in various other anatomic locations like the oral cavity. Intraoral plasma cell granulomas involving the tongue, lip, oral mucosa and gingiva have been reported in the past. This case presents a 54-year-old female with chronic periodontitis and mandibular anterior gingival overgrowth treated by Phase I therapy (scaling and root planing and excisional biopsy. Histological examination revealed inflammatory cell infiltrate containing sheets of plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma. This case highlights the need to biopsy for unusual lesions to rule out potential neoplasms.

  13. Mammary epithelial cell

    DEFF Research Database (Denmark)

    Kass, Laura; Erler, Janine Terra; Dembo, Micah

    2007-01-01

    a repertoire of transmembrane receptors, of which integrins are the best characterized. Integrins modulate cell fate by reciprocally transducing biochemical and biophysical cues between the cell and the extracellular matrix, facilitating processes such as embryonic branching morphogenesis and lactation...... in the mammary gland. During breast development and cancer progression, the extracellular matrix is dynamically altered such that its composition, turnover, processing and orientation change dramatically. These modifications influence mammary epithelial cell shape, and modulate growth factor and hormonal...

  14. Immobilized Cell Research

    Science.gov (United States)

    1990-10-31

    beads, the plasmid is twice as stable as in cells In a process where immobilized cells produce material grown in continuous culture over 200...carrageenan) or chemically cross-linked, or- Penicillium chrysogenum than in washed freely suspended ganic polymer (Ca-alginate, polyacrylamide, and mycelium ...these materials are formed into the freely suspended cells stopped after 6 days. If the beads of several millimeters in diameter by allowing the

  15. Cell Wall Proteome

    OpenAIRE

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

    2007-01-01

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

  16. Direct hydrocarbon fuel cells

    Science.gov (United States)

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  17. Lymphomas of large cells.

    Science.gov (United States)

    Staples, W G; Gétaz, E P

    1977-09-03

    Historial aspects of the classification of large-cell lymphomas are described. Immunological characterization of the lymphomas has been made possible by identification of T and B lymphocytes according to their cell membrane surface characteristics. The pathogenesis of lymphomas has been clarified by the germinal (follicular) centre cell concepts of Lennert and Lukes and Collins. The various classifications are presented and compared. Whether these subdivisions will have any relevance in the clinical context remains to be seen.

  18. Systems cell biology.

    Science.gov (United States)

    Mast, Fred D; Ratushny, Alexander V; Aitchison, John D

    2014-09-15

    Systems cell biology melds high-throughput experimentation with quantitative analysis and modeling to understand many critical processes that contribute to cellular organization and dynamics. Recently, there have been several advances in technology and in the application of modeling approaches that enable the exploration of the dynamic properties of cells. Merging technology and computation offers an opportunity to objectively address unsolved cellular mechanisms, and has revealed emergent properties and helped to gain a more comprehensive and fundamental understanding of cell biology.

  19. Cells as Drops and Drops as Cells

    Science.gov (United States)

    Dufresne, Eric R.

    2013-03-01

    How do the mechanical properties of tissues emerge from the interactions of individual cells? To shed some light on this fundamental biological question, we consider a model system of clusters of cohesive cells adherent to soft substrates. We quantify traction forces over a wide range of cluster sizes. The scaling of traction stresses with cluster size suggests the emergence of an apparent surface tension for large colonies. To explore the possible impact of cellular surface tension on physiology, we consider the behavior of liquid droplets on soft substrates. In this case, we find that the competition of surface tension and substrate elasticity can lead to rich phenomenology, mimicking certain aspects of the physiology of cells and tissues.

  20. Differentiated human stem cells resemble fetal, not adult, β cells.

    Science.gov (United States)

    Hrvatin, Sinisa; O'Donnell, Charles W; Deng, Francis; Millman, Jeffrey R; Pagliuca, Felicia Walton; DiIorio, Philip; Rezania, Alireza; Gifford, David K; Melton, Douglas A

    2014-02-25

    Human pluripotent stem cells (hPSCs) have the potential to generate any human cell type, and one widely recognized goal is to make pancreatic β cells. To this end, comparisons between differentiated cell types produced in vitro and their in vivo counterparts are essential to validate hPSC-derived cells. Genome-wide transcriptional analysis of sorted insulin-expressing (INS(+)) cells derived from three independent hPSC lines, human fetal pancreata, and adult human islets points to two major conclusions: (i) Different hPSC lines produce highly similar INS(+) cells and (ii) hPSC-derived INS(+) (hPSC-INS(+)) cells more closely resemble human fetal β cells than adult β cells. This study provides a direct comparison of transcriptional programs between pure hPSC-INS(+) cells and true β cells and provides a catalog of genes whose manipulation may convert hPSC-INS(+) cells into functional β cells.

  1. Origins of pluripotent stem cells.

    Science.gov (United States)

    Roelen, B A J; Chuva De Sousa Lopes, S M

    2011-08-01

    Different types of pluripotent stem cells can be identified and cultured in vitro. Here an overview is presented of the various pluripotent stem cells types. Embryonal carcinoma (EC) cells that have been cultured in vitro provided the groundwork for future pluripotent cell cultures. Conditions established for these cells such as culture on a feeder layer of mouse embryonic fibroblasts and the importance of fetal calf serum were initially also used for the culture of mouse embryonic stem (ES) cells derived from the inner cell masses of blastocysts. Embryonic stem cells derived from human blastocysts were found to require different conditions and are cultured in the presence of activin and basic fibroblast growth factor. Recently pluripotent stem cells have also been derived from mouse peri-implantation epiblasts. Since these epiblast stem cells (EpiSCs) require the same conditions as the human ES cells it has been suggested that human ES cells are more similar to mouse EpiSCs than to mouse ES cells. Pluripotent cell lines have also been derived from migratory primordial germ cells and spermatogonial stem cells. The creation of pluripotent stem cells from adult cells by the introduction of reprogramming transcription factors, so-called induced pluripotent stem (iPS) cells allowed the derivation of patient-specific pluripotent stem cells without the need of creation of a human blastocyst after cloning by somatic cells nuclear transfer. Recently it has become clear however that iPS cells may be quite different to ES cells in terms of epigenetics.

  2. Microencapsulation Of Living Cells

    Science.gov (United States)

    Chang, Manchium; Kendall, James M.; Wang, Taylor G.

    1989-01-01

    In experimental technique, living cells and other biological materials encapsulated within submillimeter-diameter liquid-filled spheres. Sphere material biocompatible, tough, and compliant. Semipermeable, permitting relatively small molecules to move into and out of sphere core but preventing passage of large molecules. New technique promises to make such spherical capsules at high rates and in uniform, controllable sizes. Capsules injected into patient through ordinary hypodermic needle. Promising application for technique in treatment of diabetes. Also used to encapsulate pituitary cells and thyroid hormone adrenocortical cells for treatment of other hormonal disorders, to encapsulate other secreting cells for transplantation, and to package variety of pharmaceutical products and agricultural chemicals for controlled release.

  3. [Endothelial cell adhesion molecules].

    Science.gov (United States)

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  4. Assessment of cell viability.

    Science.gov (United States)

    Johnson, Simon; Nguyen, Vy; Coder, David

    2013-01-01

    Cell viability may be judged by morphological changes or by changes in membrane permeability and/or physiological state inferred from the exclusion of certain dyes or the uptake and retention of others. This unit presents methods based on dye exclusion, esterase activity, and mitochondrial membrane potential, as well as protocols for determining the pre-fixation viability of fixed cells either before or after fixation with amine-reactive dyes suitable for a range of excitation wavelengths. Membrane-impermeable dead cell and live cell dyes as well as dye-exclusion procedures for microscopy are also included.

  5. Giant Cell Arteritis

    Science.gov (United States)

    ... Cryopyrin-Associated Autoinflammatory Syndrome (CAPS) (Juvenile) Dermatomyositis (Juvenile) Familial Mediterranean Fever (Juvenile) Fibromyalgia Giant Cell Arteritis Glucocorticoid-induced Osteoperosis ...

  6. Analysing immune cell migration.

    Science.gov (United States)

    Beltman, Joost B; Marée, Athanasius F M; de Boer, Rob J

    2009-11-01

    The visualization of the dynamic behaviour of and interactions between immune cells using time-lapse video microscopy has an important role in modern immunology. To draw robust conclusions, quantification of such cell migration is required. However, imaging experiments are associated with various artefacts that can affect the estimated positions of the immune cells under analysis, which form the basis of any subsequent analysis. Here, we describe potential artefacts that could affect the interpretation of data sets on immune cell migration. We propose how these errors can be recognized and corrected, and suggest ways to prevent the data analysis itself leading to biased results.

  7. Applications of Cell Microencapsulation.

    Science.gov (United States)

    Opara, Emmanuel C

    2017-01-01

    The goal of this chapter is to provide an overview of the different purposes for which the cell microencapsulation technology can be used. These include immunoisolation of non-autologous cells used for cell therapy; immobilization of cells for localized (targeted) delivery of therapeutic products to ablate, repair, or regenerate tissue; simultaneous delivery of multiple therapeutic agents in cell therapy; spatial compartmentalization of cells in complex tissue engineering; expansion of cells in culture; and production of different probiotics and metabolites for industrial applications. For each of these applications, specific examples are provided to illustrate how the microencapsulation technology can be utilized to achieve the purpose. However, successful use of the cell microencapsulation technology for whatever purpose will ultimately depend upon careful consideration for the choice of the encapsulating polymers, the method of fabrication (cross-linking) of the microbeads, which affects the permselectivity, the biocompatibility and the mechanical strength of the microbeads as well as environmental parameters such as temperature, humidity, osmotic pressure, and storage solutions.The various applications discussed in this chapter are illustrated in the different chapters of this book and where appropriate relevant images of the microencapsulation products are provided. It is hoped that this outline of the different applications of cell microencapsulation would provide a good platform for tissue engineers, scientists, and clinicians to design novel tissue constructs and products for therapeutic and industrial applications.

  8. Cell sorting in development.

    Science.gov (United States)

    Krens, S F Gabby; Heisenberg, Carl-Philipp

    2011-01-01

    During the development of multicellular organisms, cell fate specification is followed by the sorting of different cell types into distinct domains from where the different tissues and organs are formed. Cell sorting involves both the segregation of a mixed population of cells with different fates and properties into distinct domains, and the active maintenance of their segregated state. Because of its biological importance and apparent resemblance to fluid segregation in physics, cell sorting was extensively studied by both biologists and physicists over the last decades. Different theories were developed that try to explain cell sorting on the basis of the physical properties of the constituent cells. However, only recently the molecular and cellular mechanisms that control the physical properties driving cell sorting, have begun to be unraveled. In this review, we will provide an overview of different cell-sorting processes in development and discuss how these processes can be explained by the different sorting theories, and how these theories in turn can be connected to the molecular and cellular mechanisms driving these processes.

  9. Nanocrystal Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ilan [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

  10. Rapid cooled lens cell

    Science.gov (United States)

    Stubbs, David M.; Hsu, Ike C.

    1991-12-01

    This paper describes the optomechanical design, thermal analysis, fabrication, and test evaluation processes followed in developing a rapid cooled, infrared lens cell. Thermal analysis was the key engineering discipline exercised in the design phase. The effect of thermal stress on the lens, induced by rapid cooling of the lens cell, was investigated. Features of this lens cell that minimized the thermal stress will be discussed in a dedicated section. The results of thermal analysis on the selected lens cell design and the selection of the flow channel design in the heat exchanger will be discussed. Throughout the paper engineering drawings, illustrations, analytical results, and photographs of actual hardware are presented.

  11. Cancer stem cell metabolism

    National Research Council Canada - National Science Library

    Peiris-Pagès, Maria; Martinez-Outschoorn, Ubaldo E; Pestell, Richard G; Sotgia, Federica; Lisanti, Michael P

    2016-01-01

    .... Cancer stem cells also seem to adapt their metabolism to microenvironmental changes by conveniently shifting energy production from one pathway to another, or by acquiring intermediate metabolic phenotypes...

  12. Littoral Cells 2005

    Data.gov (United States)

    California Department of Resources — Littoral cells along the California Coast. Originally digitized by Melanie Coyne from the Assessment and Atlas of Shoreline Erosion Along the California Coast...

  13. Littoral Cells 2005

    Data.gov (United States)

    California Department of Resources — Littoral cells along the California Coast. Originally digitized by Melanie Coyne from the Assessment and Atlas of Shoreline Erosion Along the California Coast...

  14. Beta cell dynamics: beta cell replenishment, beta cell compensation and diabetes.

    Science.gov (United States)

    Cerf, Marlon E

    2013-10-01

    Type 2 diabetes, characterized by persistent hyperglycemia, arises mostly from beta cell dysfunction and insulin resistance and remains a highly complex metabolic disease due to various stages in its pathogenesis. Glucose homeostasis is primarily regulated by insulin secretion from the beta cells in response to prevailing glycemia. Beta cell populations are dynamic as they respond to fluctuating insulin demand. Beta cell replenishment and death primarily regulate beta cell populations. Beta cells, pancreatic cells, and extra-pancreatic cells represent the three tiers for replenishing beta cells. In rodents, beta cell self-replenishment appears to be the dominant source for new beta cells supported by pancreatic cells (non-beta islet cells, acinar cells, and duct cells) and extra-pancreatic cells (liver, neural, and stem/progenitor cells). In humans, beta cell neogenesis from non-beta cells appears to be the dominant source of beta cell replenishment as limited beta cell self-replenishment occurs particularly in adulthood. Metabolic states of increased insulin demand trigger increased insulin synthesis and secretion from beta cells. Beta cells, therefore, adapt to support their physiology. Maintaining physiological beta cell populations is a strategy for targeting metabolic states of persistently increased insulin demand as in diabetes.

  15. A focus on parietal cells as a renewing cell population

    Institute of Scientific and Technical Information of China (English)

    Sherif; M; Karam

    2010-01-01

    The fact that the acidsecreting parietal cells undergo continuous renewal has been ignored by many gastroenterologists and cell biologists. In the past, it was thought that these cells were static. However, by using 3Hthymidine radioautography in combination with electron microscopy, it was possible to demonstrate that parietal cells belong to a continuously renewing epithelial cell lineage. In the gastric glands, stem cells anchored in the isthmus region are responsible for the production of parietal cells...

  16. Dedifferentiated adipocyte-derived progeny cells (DFAT cells)

    OpenAIRE

    Wei, Shengjuan; Zan, Linsen; Hausman, Gary J.; Rasmussen, Theodore P; Bergen, Werner G.; Dodson, Michael V.

    2013-01-01

    Analyses of mature adipocytes have shown that they possess a reprogramming ability in vitro, which is associated with dedifferentiation. The subsequent dedifferentiated fat cells (DFAT cells) are multipotent and can differentiate into adipocytes and other cell types as well. Mature adipocytes can be easily obtained by biopsy, and the cloned progeny cells are homogeneous in vitro. Therefore, DFAT cells (a new type of stem cell) may provide an excellent source of cells for tissue regeneration, ...

  17. Regulation of B Cell to Plasma Cell Transition within the Follicular B Cell Response.

    Science.gov (United States)

    Nera, K-P; Kyläniemi, M K; Lassila, O

    2015-09-01

    Persistent humoral immunity depends on the follicular B cell response and on the generation of somatically mutated high-affinity plasma cells and memory B cells. Upon activation by an antigen, cognately activated follicular B cells and follicular T helper (TFH ) cells initiate germinal centre (GC) reaction during which high-affinity effector cells are generated. The differentiation of activated follicular B cells into plasma cells and memory B cells is guided by complex selection events, both at the cellular and molecular level. The transition of B cell into a plasma cell during the GC response involves alterations in the microenvironment and developmental state of the cell, which are guided by cell-extrinsic signals. The developmental cell fate decisions in response to these signals are coordinated by cell-intrinsic gene regulatory network functioning at epigenetic, transcriptional and post-transcriptional levels.

  18. Fuel Cell Demonstration Program

    Energy Technology Data Exchange (ETDEWEB)

    Gerald Brun

    2006-09-15

    In an effort to promote clean energy projects and aid in the commercialization of new fuel cell technologies the Long Island Power Authority (LIPA) initiated a Fuel Cell Demonstration Program in 1999 with six month deployments of Proton Exchange Membrane (PEM) non-commercial Beta model systems at partnering sites throughout Long Island. These projects facilitated significant developments in the technology, providing operating experience that allowed the manufacturer to produce fuel cells that were half the size of the Beta units and suitable for outdoor installations. In 2001, LIPA embarked on a large-scale effort to identify and develop measures that could improve the reliability and performance of future fuel cell technologies for electric utility applications and the concept to establish a fuel cell farm (Farm) of 75 units was developed. By the end of October of 2001, 75 Lorax 2.0 fuel cells had been installed at the West Babylon substation on Long Island, making it the first fuel cell demonstration of its kind and size anywhere in the world at the time. Designed to help LIPA study the feasibility of using fuel cells to operate in parallel with LIPA's electric grid system, the Farm operated 120 fuel cells over its lifetime of over 3 years including 3 generations of Plug Power fuel cells (Lorax 2.0, Lorax 3.0, Lorax 4.5). Of these 120 fuel cells, 20 Lorax 3.0 units operated under this Award from June 2002 to September 2004. In parallel with the operation of the Farm, LIPA recruited government and commercial/industrial customers to demonstrate fuel cells as on-site distributed generation. From December 2002 to February 2005, 17 fuel cells were tested and monitored at various customer sites throughout Long Island. The 37 fuel cells operated under this Award produced a total of 712,635 kWh. As fuel cell technology became more mature, performance improvements included a 1% increase in system efficiency. Including equipment, design, fuel, maintenance

  19. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  20. Small cell glioblastoma or small cell carcinoma

    DEFF Research Database (Denmark)

    Hilbrandt, Christine; Sathyadas, Sathya; Dahlrot, Rikke H

    2013-01-01

    was admitted to the hospital with left-sided loss of motor function. A MRI revealed a 6 cm tumor in the right temporoparietal area. The histology was consistent with both glioblastoma multiforme (GBM) and small cell lung carcinoma (SCLC) but IHC was suggestive of a SCLC metastasis. PET-CT revealed...

  1. Wnt-Dependent Control of Cell Polarity in Cultured Cells.

    Science.gov (United States)

    Runkle, Kristin B; Witze, Eric S

    2016-01-01

    The secreted ligand Wnt5a regulates cell polarity and polarized cell movement during development by signaling through the poorly defined noncanonical Wnt pathway. Cell polarity regulates most aspects of cell behavior including the organization of apical/basolateral membrane domains of epithelial cells, polarized cell divisions along a directional plane, and front rear polarity during cell migration. These characteristics of cell polarity allow coordinated cell movements required for tissue formation and organogenesis during embryonic development. Genetic model organisms have been used to identify multiple signaling pathways including Wnt5a that are required to establish cell polarity and regulate polarized cell behavior. However, the downstream signaling events that regulate these complex cellular processes are still poorly understood. The methods below describe assays to study Wnt5a-induced cell polarity in cultured cells, which may facilitate our understanding of these complex signaling pathways.

  2. Single-cell sequencing in stem cell biology.

    Science.gov (United States)

    Wen, Lu; Tang, Fuchou

    2016-04-15

    Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of stem cell populations, but these differences are masked when bulk cells are used for omic analysis. Single-cell sequencing technologies serve as powerful tools to dissect cellular heterogeneity comprehensively and to identify distinct phenotypic cell types, even within a 'homogeneous' stem cell population. These technologies, including single-cell genome, epigenome, and transcriptome sequencing technologies, have been developing rapidly in recent years. The application of these methods to different types of stem cells, including pluripotent stem cells and tissue-specific stem cells, has led to exciting new findings in the stem cell field. In this review, we discuss the recent progress as well as future perspectives in the methodologies and applications of single-cell omic sequencing technologies.

  3. Molecular mechanisms controlling the cell cycle in embryonic stem cells.

    Science.gov (United States)

    Abdelalim, Essam M

    2013-12-01

    Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

  4. The cell biology of T-dependent B cell activation

    DEFF Research Database (Denmark)

    Owens, T; Zeine, R

    1989-01-01

    The requirement that CD4+ helper T cells recognize antigen in association with class II Major Histocompatibility Complex (MHC) encoded molecules constrains T cells to activation through intercellular interaction. The cell biology of the interactions between CD4+ T cells and antigen-presenting cells...... activation through coculture with T cells activated by anti-T-cell receptor or anti-CD3 antibodies suggest that cellular interaction with T cells, independent of antigen presentation or lymphokine secretion, induces or triggers B cells to become responsive to T-derived lymphokines, and that this may...

  5. Stem cell regulation: Implications when differentiated cells regulate symmetric stem cell division.

    Science.gov (United States)

    Høyem, Marte Rørvik; Måløy, Frode; Jakobsen, Per; Brandsdal, Bjørn Olav

    2015-09-07

    We use a mathematical model to show that if symmetric stem cell division is regulated by differentiated cells, then changes in the population dynamics of the differentiated cells can lead to changes in the population dynamics of the stem cells. More precisely, the relative fitness of the stem cells can be affected by modifying the death rate of the differentiated cells. This result is interesting because stem cells are less sensitive than differentiated cells to environmental factors, such as medical therapy. Our result implies that stem cells can be manipulated indirectly by medical treatments that target the differentiated cells. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Dedifferentiated adipocyte-derived progeny cells (DFAT cells): Potential stem cells of adipose tissue.

    Science.gov (United States)

    Wei, Shengjuan; Zan, Linsen; Hausman, Gary J; Rasmussen, Theodore P; Bergen, Werner G; Dodson, Michael V

    2013-07-01

    Analyses of mature adipocytes have shown that they possess a reprogramming ability in vitro, which is associated with dedifferentiation. The subsequent dedifferentiated fat cells (DFAT cells) are multipotent and can differentiate into adipocytes and other cell types as well. Mature adipocytes can be easily obtained by biopsy, and the cloned progeny cells are homogeneous in vitro. Therefore, DFAT cells (a new type of stem cell) may provide an excellent source of cells for tissue regeneration, engineering and disease treatment. The dedifferentiation of mature adipocytes, the multipotent capacity of DFAT cells and comparisons and contrasts with mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPS) are discussed in this review.

  7. [Acute plasma cell leukemia].

    Science.gov (United States)

    Monsalbe, V; Domíngues, C; Roa, I; Busel, D; González, S

    1989-01-01

    Plasma Cell Leukemia is a very rare form of plasmocytic dyscrasia, whose clinical and pathological characteristics warrant its recognition as a distinct subentity. We report the case of a 60 years old man who presented a rapidly fatal acute plasma cell leukemia, with multiple osteolytic lesions, hipercalcemia, renal and cardiac failure.

  8. T-cell costimulation

    DEFF Research Database (Denmark)

    Owens, T

    1996-01-01

    The CD40L molecule expressed by CD4+ regulatory T lymphocytes is known to deliver signals that activate B cells and macrophages. It now appears that CD40L regulates T cells themselves, during both their development and their participation in adaptive immune responses....

  9. Cell-Assisted Lipotransfer

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Quaade, Marlene Louise; Sørensen, Jens Ahm

    2016-01-01

    -derived stromal cells (ASCs) to enrich the fat graft, a procedure termed cell-assisted lipotransfer (CAL). The aim of this review was to systematically review the current preclinical and clinical evidence for the efficacy of CAL compared with conventional lipotransfer. MATERIALS AND METHODS: A systematic search...

  10. Modeling: driving fuel cells

    Directory of Open Access Journals (Sweden)

    Michael Francis

    2002-05-01

    Fuel cells were invented in 1839 by Sir William Grove, a Welsh judge and gentleman scientist, as a result of his experiments on the electrolysis of water. To put it simply, fuel cells are electrochemical devices that take hydrogen gas from fuel, combine it with oxygen from the air, and generate electricity and heat, with water as the only by-product.

  11. Cystic Granular Cell Ameloblastoma

    OpenAIRE

    Thillaikarasi, Rathnavel; Balaji, Jayaram; Gupta, Bhawna; Ilayarja, Vadivel; Vani, Nandimandalam Venkata; Vidula, Balachander; Saravanan, Balasubramaniam; Ponniah, Irulandy

    2010-01-01

    Ameloblastoma is a locally aggressive benign epithelial odontogenic tumor, while unicystic ameloblastoma is a relatively less aggressive variant. Although rare in unicystic or cystic ameloblastoma, granular cell change in ameloblastoma is a recognized phenomenon. The purpose of the present article is to report a case of cystic granular cell ameloblastoma in 34-year old female.

  12. The Constitution by Cell

    Science.gov (United States)

    Greenhut, Stephanie; Jones, Megan

    2010-01-01

    On their visit to the National Archives Experience in Washington, D.C., students in Jenni Ashley and Gay Brock's U.S. history classes at the Potomac School in McLean, Virginia, participated in a pilot program called "The Constitution by Cell." Armed with their cell phones, a basic understanding of the Constitution, and a willingness to participate…

  13. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  14. Mesangial cell biology

    Energy Technology Data Exchange (ETDEWEB)

    Abboud, Hanna E., E-mail: Abboud@uthscsa.edu

    2012-05-15

    Mesangial cells originate from the metanephric mesenchyme and maintain structural integrity of the glomerular microvascular bed and mesangial matrix homeostasis. In response to metabolic, immunologic or hemodynamic injury, these cells undergo apoptosis or acquire an activated phenotype and undergo hypertrophy, proliferation with excessive production of matrix proteins, growth factors, chemokines and cytokines. These soluble factors exert autocrine and paracrine effects on the cells or on other glomerular cells, respectively. MCs are primary targets of immune-mediated glomerular diseases such as IGA nephropathy or metabolic diseases such as diabetes. MCs may also respond to injury that primarily involves podocytes and endothelial cells or to structural and genetic abnormalities of the glomerular basement membrane. Signal transduction and oxidant stress pathways are activated in MCs and likely represent integrated input from multiple mediators. Such responses are convenient targets for therapeutic intervention. Studies in cultured MCs should be supplemented with in vivo studies as well as examination of freshly isolated cells from normal and diseases glomeruli. In addition to ex vivo morphologic studies in kidney cortex, cells should be studied in their natural environment, isolated glomeruli or even tissue slices. Identification of a specific marker of MCs should help genetic manipulation as well as selective therapeutic targeting of these cells. Identification of biological responses of MCs that are not mediated by the renin–angiotensin system should help development of novel and effective therapeutic strategies to treat diseases characterized by MC pathology.

  15. Tumor cell metabolism

    Science.gov (United States)

    Romero-Garcia, Susana; Lopez-Gonzalez, Jose Sullivan; B´ez-Viveros, José Luis; Aguilar-Cazares, Dolores

    2011-01-01

    Cancer is a genetic disease that is caused by mutations in oncogenes, tumor suppressor genes and stability genes. The fact that the metabolism of tumor cells is altered has been known for many years. However, the mechanisms and consequences of metabolic reprogramming have just begun to be understood. In this review, an integral view of tumor cell metabolism is presented, showing how metabolic pathways are reprogrammed to satisfy tumor cell proliferation and survival requirements. In tumor cells, glycolysis is strongly enhanced to fulfill the high ATP demands of these cells; glucose carbons are the main building blocks in fatty acid and nucleotide biosynthesis. Glutaminolysis is also increased to satisfy NADPH regeneration, whereas glutamine carbons replenish the Krebs cycle, which produces metabolites that are constantly used for macromolecular biosynthesis. A characteristic feature of the tumor microenvironment is acidosis, which results from the local increase in lactic acid production by tumor cells. This phenomenon is attributed to the carbons from glutamine and glucose, which are also used for lactic acid production. Lactic acidosis also directs the metabolic reprogramming of tumor cells and serves as an additional selective pressure. Finally, we also discuss the role of mitochondria in supporting tumor cell metabolism. PMID:22057267

  16. Transparent solar cell module

    Science.gov (United States)

    Antonides, G. J.; Dillard, P. A.; Fritz, W. M.; Lott, D. P.

    1979-01-01

    Modified solar cell module uses high transmission glass and adhesives, and heat dissipation to boost power per unit area by 25% (9.84% efficiency based on cell area at 60 C and 100 mW/sq cm flux). Design is suited for automatic production and is potentially more cost effective.

  17. Sickle Cell Trait

    Science.gov (United States)

    ... Websites About Us Information For… Media Policy Makers Sickle Cell Trait Language: English (US) Español (Spanish) Recommend on Facebook Tweet Share Compartir Get Screened for Sickle Cell Trait Did you know there’s more than one way ...

  18. Toward sustainable fuel cells

    DEFF Research Database (Denmark)

    Stephens, Ifan; Rossmeisl, Jan; Chorkendorff, Ib

    2016-01-01

    to a regular gasoline car. However, current fuel cells require 0.25 g of platinum (Pt) per kilowatt of power (2) as catalysts to drive the electrode reactions. If the entire global annual production of Pt were devoted to fuel cell vehicles, fewer than 10 million vehicles could be produced each year, a mere 10...

  19. MICROBIAL FUEL CELL

    DEFF Research Database (Denmark)

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  20. Stem cells in dermatology.

    Science.gov (United States)

    Ogliari, Karolyn Sassi; Marinowic, Daniel; Brum, Dario Eduardo; Loth, Fabrizio

    2014-01-01

    Preclinical and clinical research have shown that stem cell therapy could be a promising therapeutic option for many diseases in which current medical treatments do not achieve satisfying results or cure. This article describes stem cells sources and their therapeutic applications in dermatology today.