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Sample records for cell patterning plant

  1. Patterns of cell division revealed by transcriptional regulation of genes during the cell cycle in plants.

    OpenAIRE

    Fobert, P R; Coen, E S; Murphy, G. J.; Doonan, J H

    1994-01-01

    Transcripts from five cell cycle related genes accumulate in isolated cells dispersed throughout the actively dividing regions of plant meristems. We propose that this pattern reflects gene expression during particular phases of the cell division cycle. The high proportion of isolated cells suggests that synchrony between daughter cells is rapidly lost following mitosis. This is the first time that such a cell specific expression pattern has been described in a higher organism. Counterstainin...

  2. Patterns of Stem Cell Divisions Contribute to Plant Longevity.

    Science.gov (United States)

    Burian, Agata; Barbier de Reuille, Pierre; Kuhlemeier, Cris

    2016-06-01

    The lifespan of plants ranges from a few weeks in annuals to thousands of years in trees. It is hard to explain such extreme longevity considering that DNA replication errors inevitably cause mutations. Without purging through meiotic recombination, the accumulation of somatic mutations will eventually result in mutational meltdown, a phenomenon known as Muller's ratchet. Nevertheless, the lifespan of trees is limited more often by incidental disease or structural damage than by genetic aging. The key determinants of tree architecture are the axillary meristems, which form in the axils of leaves and grow out to form branches. The number of branches is low in annual plants, but in perennial plants iterative branching can result in thousands of terminal branches. Here, we use stem cell ablation and quantitative cell-lineage analysis to show that axillary meristems are set aside early, analogous to the metazoan germline. While neighboring cells divide vigorously, axillary meristem precursors maintain a quiescent state, with only 7-9 cell divisions occurring between the apical and axillary meristem. During iterative branching, the number of branches increases exponentially, while the number of cell divisions increases linearly. Moreover, computational modeling shows that stem cell arrangement and positioning of axillary meristems distribute somatic mutations around the main shoot, preventing their fixation and maximizing genetic heterogeneity. These features slow down Muller's ratchet and thereby extend lifespan. PMID:27161504

  3. Turing Patterns Inside Cells

    OpenAIRE

    Strier, Damián E.; Ponce Dawson, Silvina

    2007-01-01

    Concentration gradients inside cells are involved in key processes such as cell division and morphogenesis. Here we show that a model of the enzymatic step catalized by phosphofructokinase (PFK), a step which is responsible for the appearance of homogeneous oscillations in the glycolytic pathway, displays Turing patterns with an intrinsic length-scale that is smaller than a typical cell size. All the parameter values are fully consistent with classic experiments on glycolytic oscillations and...

  4. Turing patterns inside cells.

    Directory of Open Access Journals (Sweden)

    Damián E Strier

    Full Text Available Concentration gradients inside cells are involved in key processes such as cell division and morphogenesis. Here we show that a model of the enzymatic step catalized by phosphofructokinase (PFK, a step which is responsible for the appearance of homogeneous oscillations in the glycolytic pathway, displays Turing patterns with an intrinsic length-scale that is smaller than a typical cell size. All the parameter values are fully consistent with classic experiments on glycolytic oscillations and equal diffusion coefficients are assumed for ATP and ADP. We identify the enzyme concentration and the glycolytic flux as the possible regulators of the pattern. To the best of our knowledge, this is the first closed example of Turing pattern formation in a model of a vital step of the cell metabolism, with a built-in mechanism for changing the diffusion length of the reactants, and with parameter values that are compatible with experiments. Turing patterns inside cells could provide a check-point that combines mechanical and biochemical information to trigger events during the cell division process.

  5. Stable expression of human β1,4-galactosyltransferase in plant cells modifies N-linked glycosylation patterns

    OpenAIRE

    Palacpac, Nirianne Q.; Yoshida, Shohei; Sakai, Hiromi; Kimura, Yoshinobu; Fujiyama, Kazuhito; Yoshida, Toshiomi; Seki, Tatsuji

    1999-01-01

    β1,4-Galactosyltransferase (UDP galactose: β-N-acetylglucosaminide: β1,4-galactosyltransferase; EC 2.4.1.22) catalyzes the transfer of galactose from UDP-Gal to N-acetylglucosamine in the penultimate stages of the terminal glycosylation of N-linked complex oligosaccharides in mammalian cells. Tobacco BY2 cells lack this Golgi enzyme. To determine to what extent the production of a mammalian glycosyltransferase can alter the glycosylation pathway of plant cells, tobacco BY2 suspension-cultured...

  6. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Directory of Open Access Journals (Sweden)

    Abercrombie Jason M

    2011-07-01

    and pollen-specific functions in early seed plants and was then recruited to novel expression patterns and functions within pollen tube walls in an ancestor of extant angiosperms.

  7. Pathological modifications of plant stem cell destiny

    Science.gov (United States)

    In higher plants, the shoot apex contains undifferentiated stem cells that give rise to various tissues and organs. The fate of these stem cells determines the pattern of plant growth as well as reproduction; and such fate is genetically preprogrammed. We found that a bacterial infection can derai...

  8. The Plant Cell Surface

    Institute of Scientific and Technical Information of China (English)

    Anne-Mie C.Emons; Kurt V.Fagerstedt

    2010-01-01

    @@ Multicellular organization and tissue construction has evolved along essentially different lines in plants and animals. Since plants do not run away, but are anchored in the soil, their tissues are more or less firm and stiff. This strength stems from the cell walls, which encase the fragile cytoplasm, and protect it.

  9. Patterning Stem Cell Differentiation

    OpenAIRE

    Vunjak-Novakovic, Gordana

    2008-01-01

    Regulation of cell differentiation and assembly remains a fundamental question in developmental biology. Now, a report from the Chen laboratory (Ruiz and Chen, 2008) describes an approach that represents a major step toward a more profound understanding of the geometric-force control of stem cell differentiation.

  10. Patterns of Gondwana plant colonisation anddiversification

    Science.gov (United States)

    Anderson, J. M.; Anderson, H. M.; Archangelsky, S.; Bamford, M.; Chandra, S.; Dettmann, M.; Hill, R.; McLoughlin, S.; Rösler, O.

    Charting the broad patterns of vascular plant evolution for Gondwana againstthe major global environmental shifts and events is attempted here for the first time. This is based on the analysis of the major vascular plant-bearing formations of the southern continents (plus India) correlated against the standard geological time-scale. Australia, followed closely by South America, are shown to yield by far the most complete sequences of productive strata. Ten seminal turnover pulses in the unfolding evolutionary picture are identified and seen to be linked to continental drift, climate change and mass global extinctions. The rise of vascular plants along the tropical belt, for instance, followed closely after the end-Ordovician warming and extinction. Equally remarkable is that the Late Devonian extinction may have caused both the terrestrialisation of the vertebrates and the origin of the true gymnosperms. The end-Permian extinction, closure of Iapetus, together with warming, appears to have set in motion an unparalleled, explosive, gymnosperm radiation; whilst the Late Triassic extinction dramatically curtailed it. It is suggested that the latitudinal diversity gradient clearly recognised today, where species richness increases towards the tropics, may have been partly reversed during phases of Hot House climate. Evidence hints at this being particularly so at the heyday of the gymnosperms in the Late Triassic super-Hot House world. As for the origin of terrestrial, vascular, plant life, the angiosperms seem closely linked to a phase of marked shift from Ice House to Hot House. Insect and tetrapod evolutionary patterns are discussed in the context of the plants providing the base of the ever-changing ecosystems. Intimate co-evolution is often evident. This isn't always the case, for example the non-linkage between the dominant, giant, long-necked, herbivorous sauropod dinosaurs and the dramatic radiation of the flowering plants in the Mid Cretaceous.

  11. Transcriptional Regulation of Pattern-Triggered Immunity in Plants.

    Science.gov (United States)

    Li, Bo; Meng, Xiangzong; Shan, Libo; He, Ping

    2016-05-11

    Perception of microbe-associated molecular patterns (MAMPs) by cell-surface-resident pattern recognition receptors (PRRs) induces rapid, robust, and selective transcriptional reprogramming, which is central for launching effective pattern-triggered immunity (PTI) in plants. Signal relay from PRR complexes to the nuclear transcriptional machinery via intracellular kinase cascades rapidly activates primary immune response genes. The coordinated action of gene-specific transcription factors and the general transcriptional machinery contribute to the selectivity of immune gene activation. In addition, PRR complexes and signaling components are often transcriptionally upregulated upon MAMP perception to ensure the robustness and sustainability of PTI outputs. In this review, we discuss recent advances in deciphering the signaling pathways and regulatory mechanisms that coordinately lead to timely and accurate MAMP-induced gene expression in plants. PMID:27173932

  12. RNA silencing can explain chlorotic infection patterns on plant leaves

    Directory of Open Access Journals (Sweden)

    Hogeweg Paulien

    2008-11-01

    Full Text Available Abstract Background RNA silencing has been implicated in virus symptom development in plants. One common infection symptom in plants is the formation of chlorotic tissue in leaves. Chlorotic and healthy tissue co-occur on a single leaf and form patterns. It has been shown that virus levels in chlorotic tissue are high, while they are low in healthy tissue. Additionally, the presence of siRNAs is confined to the chlorotic spots and the boundaries between healthy and infected tissue. These results strongly indicate that the interaction between virus growth and RNA silencing plays a role in the formation of infection patterns on leaves. However, how RNA silencing leads to the intricate patterns is not known. Results Here we elucidate the mechanisms leading to infection patterns and the conditions which lead to the various patterns observed. We present a modeling approach in which we combine intra- and inter-cellular dynamics of RNA silencing and viral growth. We observe that, due to the spread of viruses and the RNA silencing response, parts of the tissue become infected while other parts remain healthy. As is observed in experiments high virus levels coincide with high levels of siRNAs, and siRNAs are also present in the boundaries between infected and healthy tissue. We study how single- and double-stranded cleavage by Dicer and amplification by RNA-dependent RNA polymerase can affect the patterns formed. Conclusion This work shows that RNA silencing and virus growth within a cell, and the local spread of virions and siRNAs between cells can explain the heterogeneous spread of virus in leaf tissue, and therewith the observed infection patterns in plants.

  13. Reaction-diffusion pattern in shoot apical meristem of plants.

    Directory of Open Access Journals (Sweden)

    Hironori Fujita

    Full Text Available A fundamental question in developmental biology is how spatial patterns are self-organized from homogeneous structures. In 1952, Turing proposed the reaction-diffusion model in order to explain this issue. Experimental evidence of reaction-diffusion patterns in living organisms was first provided by the pigmentation pattern on the skin of fishes in 1995. However, whether or not this mechanism plays an essential role in developmental events of living organisms remains elusive. Here we show that a reaction-diffusion model can successfully explain the shoot apical meristem (SAM development of plants. SAM of plants resides in the top of each shoot and consists of a central zone (CZ and a surrounding peripheral zone (PZ. SAM contains stem cells and continuously produces new organs throughout the lifespan. Molecular genetic studies using Arabidopsis thaliana revealed that the formation and maintenance of the SAM are essentially regulated by the feedback interaction between WUSHCEL (WUS and CLAVATA (CLV. We developed a mathematical model of the SAM based on a reaction-diffusion dynamics of the WUS-CLV interaction, incorporating cell division and the spatial restriction of the dynamics. Our model explains the various SAM patterns observed in plants, for example, homeostatic control of SAM size in the wild type, enlarged or fasciated SAM in clv mutants, and initiation of ectopic secondary meristems from an initial flattened SAM in wus mutant. In addition, the model is supported by comparing its prediction with the expression pattern of WUS in the wus mutant. Furthermore, the model can account for many experimental results including reorganization processes caused by the CZ ablation and by incision through the meristem center. We thus conclude that the reaction-diffusion dynamics is probably indispensable for the SAM development of plants.

  14. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  15. Chromatin remodeling in plant cell culture: patterns of DNA methylation and histone H3 and H4 acetylation vary during growth of asynchronous potato cell suspensions.

    Science.gov (United States)

    Law, R David; Suttle, Jeffrey C

    2005-06-01

    Changes in DNA cytosine methylation and core histone multi-acetylation were determined in cell suspension cultures of potato (Solanum tuberosum L. cv. Russet Burbank) during 15 days of in vitro culture. Cell subculture induced a transient 33% decrease in genome-wide 5-methylcytosine (5mC) content and a transient threefold increase in transcription rates that were most evident at 6 and 9 days after subculture, respectively. In contrast to the global reduction in 5mC content, subculture resulted in a transient twofold increase in 5mC levels within 5'-CCGG-3' sequences and no detectable change in 5'-CG-3' methylation. Multi-acetylation of histones H3.1, H3.2 and H4 rose 2-, 1.5- and 3-fold by 9, 9 and 12 days after subculture, respectively. All observed epigenetic changes were reset during aging of cell cultures. Inclusion of the histone deacetylase inhibitor trichostatin A (TSA) and/or the cytosine methylation inhibitor 5-azacytidine (5AC) in culture sequentially decreased genome-wide 5mC levels by approximately 25% at day 9, then decreased 5'-mCmCGG-3' by 30-50% and increased H3 and H4 multi-acetylation by 30-60% at day 15, compared to controls. Treatment with 5AC or TSA alone or in combination had no effect on RNA synthesis at day 9. At day 15, 5AC treatment remained ineffective, while de novo RNA synthesis was approximately twofold higher in cells grown in both inhibitors or in TSA alone. Collectively, these results demonstrate that in potato suspension cultures, rapid, reversible changes in 5mC levels precede regulatory post-translational acetylation of core histones, and suggest that interactions between these epigenetic processes appear to be necessary to power transcription and growth induction in potato cells. PMID:15922608

  16. Head-neck domain of Arabidopsis myosin XI, MYA2, fused with GFP produces F-actin patterns that coincide with fast organelle streaming in different plant cells

    Directory of Open Access Journals (Sweden)

    Holweg Carola L

    2008-07-01

    Full Text Available Abstract Background The cytoskeletal mechanisms that underlie organelle transport in plants are intimately linked to acto-myosin function. This function is mediated by the attachment of myosin heads to F-actin and the binding of cargo to the tails. Acto-myosin also powers vigorous cytoplasmic streaming in plant cells. Class XI myosins exhibit strikingly fast velocities and may have extraordinary roles in cellular motility. Studies of the structural basis of organelle transport have focused on the cargo-binding tails of myosin XI, revealing a close relationship with the transport of peroxisomes, mitochondria, and Golgi-vesicles. Links between myosin heads and F-actin-based motility have been less investigated. To address this function, we performed localization studies using the head-neck domain of AtMYA2, a myosin XI from Arabidopsis. Results We expressed the GFP-fused head-neck domain of MYA2 in epidermal cells of various plant species and found that it associated with F-actin. By comparison to other markers such as fimbrin and talin, we revealed that the myosin-labeled F-actin was of a lower quality and absent from the fine microfilament arrays at the cell cortex. However, it colocalized with cytoplasmic (transvacuolar F-actin in areas coinciding with the tracks of fast organelles. This observation correlates well with the proposed function of myosin XI in organelle trafficking. The fact that organelle streaming was reduced in cells expressing the GFP-MYA2-head6IQ indicated that the functionless motor protein inhibits endogenous myosins. Furthermore, co-expression of the GFP-MYA2-head6IQ with other F-actin markers disrupted its attachment to F-actin. In nuclei, the GFP-myosin associated with short bundles of F-actin. Conclusion The localization of the head of MYA2 in living plant cells, as investigated here for the first time, suggests a close linkage between this myosin XI and cytoplasmic microfilaments that support the rapid streaming of

  17. Regulation of cell division in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, T.W.

    1992-01-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant's essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  18. Organelle Extensions in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Jaideep Mathur; Alena Mammone; Kiah A.Barton

    2012-01-01

    Cell walls lock each cell in a specific position within the supraorganization of a plant.Despite its fixed location,each cell must be able to sense alterations in its immediate environment and respond rapidly to ensure the optimal functioning,continued growth and development,and eventual long-term survival of the plant.The ultra-structural detail that underlies our present understanding of the plant cell has largely been acquired from fixed and processed material that does not allow an appreciation of the dynamic nature of sub-cellular events in the cell.In recent years,fluorescent proteinaided imaging of living plant cells has added to our understanding of the dynamic nature of the plant cell.One of the major outcomes of live imaging of plant cells is the growing appreciation that organelle shapes are not fixed,and many organelles extend their surface transiently in rapid response to environmental stimuli.In many cases,the extensions appear as tubules extending from the main organelle.Specific terms such as stromules from plastids,matrixules from mitochondria,and peroxules from peroxisomes have been coined to describe the extensions.Here,we review our present understanding of organelle extensions and discuss how they may play potential roles in maintaining cellular homeostasis in plant cells.

  19. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  20. Celebrating Plant Cells: A Special Issue on Plant Cell Biology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A special issue on plant cell biology is long overdue for JIPB! In the last two decades or so, the plant biology community has been thrilled by explosive discoveries regarding the molecular and genetic basis of plant growth, development, and responses to the environment, largely owing to recent maturation of model systems like Arabidopsis thaliana and the rice Oryza sativa, as well as the rapid development of high throughput technologies associated with genomics and proteomics.

  1. Dense pattern optical multipass cell

    Science.gov (United States)

    Silver, Joel A [Santa Fe, NM

    2009-01-13

    A multiple pass optical cell and method comprising providing a pair of opposed cylindrical mirrors having curved axes with substantially equal focal lengths, positioning an entrance hole for introducing light into the cell and an exit hole for extracting light from the cell, wherein the entrance hole and exit hole are coextensive or non-coextensive, introducing light into the cell through the entrance hole, and extracting light from the cell through the exit hole.

  2. Elevational Patterns of Plant Richness in the Taibai Mountain, China

    Directory of Open Access Journals (Sweden)

    Lili Tang

    2014-01-01

    Full Text Available The elevational distribution of plant diversity is a popular issue in ecology and biogeography, and several studies have examined the determinants behind plant diversity patterns. In this study, using published data of the local flora of Taibai Mountain, we explored the effects of spatial and climatic factors on plant species richness. We also evaluated Rapoport’s elevational rule by examining the relationship between elevational range size and midpoint. Species richness patterns were regressed against area, middle domain effect (MDE, mean annual temperature (MAT, and mean annual precipitation (MAP. The results showed that richness of overall plants, seed plants, bryophytes, and ferns all showed hump-shaped patterns along the elevational gradient, although the absolute elevation of richness peaks differed in different plant groups. Species richness of each plant group was all associated strongly with MAT and MAP. In addition to climatic factors, overall plants and seed plants were more related to area in linear regression models, while MDE was a powerful explanatory variable for bryophytes. Rapoport’s elevational rule on species richness was not supported. Our study suggests that a combined interaction of spatial and climatic factors influences the elevational patterns of plant species richness on Taibai Mountain, China.

  3. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    Science.gov (United States)

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae. PMID:24934960

  4. Pattern formation by vascular mesenchymal cells

    OpenAIRE

    Garfinkel, Alan; Tintut, Yin; Petrasek, Danny; Boström, Kristina; Demer, Linda L.

    2004-01-01

    In embryogenesis, immature mesenchymal cells aggregate and organize into patterned tissues. Later in life, a pathological recapitulation of this process takes place in atherosclerotic lesions, when vascular mesenchymal cells organize into trabecular bone tissue within the artery wall. Here we show that multipotential adult vascular mesenchymal cells self-organize in vitro into patterns that are predicted by a mathematical model based on molecular morphogens interacting in a reaction-diffusion...

  5. Cell-cell interactions during patterning of the Arabidopsis anther.

    Science.gov (United States)

    Feng, Xiaoqi; Dickinson, Hugh G

    2010-04-01

    Key steps in the evolution of the angiosperm anther include the patterning of the concentrically organized microsporangium and the incorporation of four such microsporangia into a leaf-like structure. Mutant studies in the model plant Arabidopsis thaliana are leading to an increasingly accurate picture of (i) the cell lineages culminating in the different cell types present in the microsporangium (the microsporocytes, the tapetum, and the middle and endothecial layers), and (ii) some of the genes responsible for specifying their fates. However, the processes that confer polarity on the developing anther and position the microsporangia within it remain unclear. Certainly, data from a range of experimental strategies suggest that hormones play a central role in establishing polarity and the patterning of the anther initial, and may be responsible for locating the microsporangia. But the fact that microsporangia were originally positioned externally suggests that their development is likely to be autonomous, perhaps with the reproductive cells generating signals controlling the growth and division of the investing anther epidermis. These possibilities are discussed in the context of the expression of genes which initiate and maintain male and female reproductive development, and in the perspective of our current views of anther evolution. PMID:20298223

  6. Productivity growth patterns in US dairy products manufacturing plants

    NARCIS (Netherlands)

    Geylani, P.C.; Stefanou, S.E.

    2011-01-01

    We analyse the productivity growth patterns in the US dairy products industry using the Census Bureau's plant-level data set. We decompose Total Factor Productivity (TFP) growth into the scale and technical change components and analyse variability of plants' productivity by constructing transition

  7. Programmed cell death: a way of life for plants.

    OpenAIRE

    Greenberg, J T

    1996-01-01

    Cell death in higher plants has been widely observed in predictable patterns throughout development and in response to pathogenic infection. Genetic, biochemical, and morphological evidence suggests that these cell deaths occur as active processes and can be defined formally as examples of programmed cell death (PCD). Intriguingly, plants have at least two types of PCD, an observation that is also true of PCD in animals [Schwartz, L. M., Smith, W.W., Jones, M. E. E. & Osborne, B. A. (1993) Pr...

  8. 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.

  9. Plant-Herbivore Interaction: Dissection of the Cellular Pattern of Tetranychus urticae Feeding on the Host Plant

    Science.gov (United States)

    Bensoussan, Nicolas; Santamaria, M. Estrella; Zhurov, Vladimir; Diaz, Isabel; Grbić, Miodrag; Grbić, Vojislava

    2016-01-01

    The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. It is being established as a model for chelicerate herbivores with tools that enable tracking of reciprocal responses in plant-spider mite interactions. However, despite their important pest status and a growing understanding of the molecular basis of interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Here, utilizing histology and microscopy methods, we uncovered several key features of T. urticae feeding. By following the stylet path within the plant tissue, we determined that the stylet penetrates the leaf either in between epidermal pavement cells or through a stomatal opening, without damaging the epidermal cellular layer. Our recordings of mite feeding established that duration of the feeding event ranges from several minutes to more than half an hour, during which time mites consume a single mesophyll cell in a pattern that is common to both bean and Arabidopsis plant hosts. In addition, this study determined that leaf chlorotic spots, a common symptom of mite herbivory, do not form as an immediate consequence of mite feeding. Our results establish a cellular context for the plant-spider mite interaction that will support our understanding of the molecular mechanisms and cell signaling associated with spider mite feeding. PMID:27512397

  10. Auxiliary pattern for cell-based OPC

    Science.gov (United States)

    Kahng, Andrew B.; Park, Chul-Hong

    2006-10-01

    The runtime of model-based optical proximity correction (OPC) tools has grown unacceptably with each successive technology generation, and has emerged as one of the major bottlenecks for turnaround time (TAT) of IC data preparation and manufacturing. The cell-based OPC approach improves runtime by performing OPC once per cell definition as opposed to once per cell instantiation in the layout. However, cell-based OPC does not comprehend inter-cell optical interactions that affect feature printability in a layout context. In this work, we propose auxiliary pattern-enabled cell-based OPC which can minimize the CD differences between cell-based OPC and model-based OPC. To enable effective insertion of auxiliary pattern (AP) in the design, we also propose a post-placement optimization of a standard cell block with respect to detailed placement. By dynamic programming-based placement perturbation, we achieve 100% AP applicability in designs with placement utilizations of cell-based OPC with AP can match gate edge placement error (EPE) count of model-based OPC within 4%. This is an improvement of 90%, on average, over cell-based OPC without APs. The AP-based OPC approach can reduce OPC runtimes versus model-based OPC by up to 40X in our benchmark designs. We can also achieve reduction of GDSII file size and ORC runtimes due to hierarchy maintenance of cell-based OPC.

  11. Microbe Associated Molecular Pattern Signaling in Guard Cells.

    Science.gov (United States)

    Ye, Wenxiu; Murata, Yoshiyuki

    2016-01-01

    Stomata, formed by pairs of guard cells in the epidermis of terrestrial plants, regulate gas exchange, thus playing a critical role in plant growth and stress responses. As natural openings, stomata are exploited by microbes as an entry route. Recent studies reveal that plants close stomata upon guard cell perception of molecular signatures from microbes, microbe associated molecular patterns (MAMPs), to prevent microbe invasion. The perception of MAMPs induces signal transduction including recruitment of second messengers, such as Ca(2+) and H2O2, phosphorylation events, and change of transporter activity, leading to stomatal movement. In the present review, we summarize recent findings in signaling underlying MAMP-induced stomatal movement by comparing with other signalings. PMID:27200056

  12. Stem cells: a plant biology perspective

    NARCIS (Netherlands)

    Scheres, B.J.G.

    2005-01-01

    A recent meeting at the Juan March Foundation in Madrid, Spain brought together plant biologists to discuss the characteristics of plant stem cells that are unique and those that are shared by stem cells from the animal kingdom

  13. Regulation of Water in Plant Cells

    Science.gov (United States)

    Kowles, Richard V.

    2010-01-01

    Cell water relationships are important topics to be included in cell biology courses. Differences exist in the control of water relationships in plant cells relative to control in animal cells. One important reason for these differences is that turgor pressure is a consideration in plant cells. Diffusion and osmosis are the underlying factors…

  14. Plant Cell Adaptive Responses to Microgravity

    Science.gov (United States)

    Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

    Microgravity is an abnormal environmental condition that plays no role in the functioning of biosphere. Nevertheless, the chronic effect of microgravity in space flight as an unfamiliar factor does not prevent the development of adaptive reactions at the cellular level. In real microgravity in space flight under the more or less optimal conditions for plant growing, namely temperature, humidity, CO2, light intensity and directivity in the hardware angiosperm plants perform an “reproductive imperative”, i.e. they flower, fruit and yield viable seeds. It is known that cells of a multicellular organism not only take part on reactions of the organism but also carry out processes that maintain their integrity. In light of these principles, the problem of the identification of biochemical, physiological and structural patterns that can have adaptive significance at the cellular and subcellular level in real and simulated microgravity is considered. Cytological studies of plants developing in real and simulated microgravity made it possible to establish that the processes of mitosis, cytokinesis, and tissue differentiation of vegetative and generative organs are largely normal. At the same time, under microgravity, essential reconstruction in the structural and functional organization of cell organelles and cytoskeleton, as well as changes in cell metabolism and homeostasis have been described. In addition, new interesting data concerning the influence of altered gravity on lipid peroxidation intensity, the level of reactive oxygen species, and antioxidant system activity, just like on the level of gene expression and synthesis of low-molecular and high-molecular heat shock proteins were recently obtained. So, altered gravity caused time-dependent increasing of the HSP70 and HSP90 levels in cells, that may indicate temporary strengthening of their functional loads that is necessary for re-establish a new cellular homeostasis. Relative qPCR results showed that

  15. Naturalization of introduced plants: ecological drivers of biogeographic patterns

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    2012-01-01

    Roč. 196, č. 2 (2012), s. 383-396. ISSN 0028-646X R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : plant invasions * naturalization * macroecological patterns Subject RIV: EF - Botanics Impact factor: 6.736, year: 2012

  16. Cell pattern in adult human corneal endothelium.

    Directory of Open Access Journals (Sweden)

    Carlos H Wörner

    Full Text Available A review of the current data on the cell density of normal adult human endothelial cells was carried out in order to establish some common parameters appearing in the different considered populations. From the analysis of cell growth patterns, it is inferred that the cell aging rate is similar for each of the different considered populations. Also, the morphology, the cell distribution and the tendency to hexagonallity are studied. The results are consistent with the hypothesis that this phenomenon is analogous with cell behavior in other structures such as dry foams and grains in polycrystalline materials. Therefore, its driving force may be controlled by the surface tension and the mobility of the boundaries.

  17. Radiocontamination patterns of vascular plants in a forest ecosystem

    International Nuclear Information System (INIS)

    This study is based on measurements of radiocesium and potassium-40 in leaves, stems and roots of 48 vascular plants in a natural beech forest in the Carnic Alps (NE Italy). The data have been submitted to numerical classification, and the main results are: (a) radiocontamination patterns and ecology of the species are well related, (b) three main groups of species with different radiocontamination can be distinguished: plants in clearings, forest plants rooting in the organic soil layer, forest plants rooting in the mineral layer; (c) radiocesium tends to be retained in the roots, especially in plants in the clearings; (d) Pteridophytes, contrary to all other plants, are able to discriminate between cesium and potassium at leaf level; (e) for all other species, cesium and potassium, once taken up by the plant, exhibit a similar behaviour; (f) total contamination by radiocesium is related to the depth of the root systems, and to the unequal distribution of radiocesium in the soil profile. Species-specific mechanisms of differential absorption are not evident in the investigated forest; the radiocontamination of plants can be easily explained in ecological terms. Radiocontamination on a water basis (Bq/l) is suggested as being much more appropriate for solving certain radioecological problems

  18. Effect of pre-planting irrigation, maize planting pattern and nitrogen on weed seed bank population.

    Science.gov (United States)

    Hemmati, E; Vazan, S; Oveisi, M

    2011-01-01

    Pre-planting irrigation and planting patterns are important factors in weed management that effect on seed bank. Additionally, the nitrogen is the most important factor in plant growth that affects weed-crop competition and ultimately, seed rain into the soil. A field experiment was conducted to study the effect of nitrogen application rates, pre-planting irrigation and maize planting patterns on weed seed bank population. Experimental factors were nitrogen rates at 4 levels (200, 300, 400 and 500 kg per hectare) as main plot; and pre-planting irrigation at 2 levels (irrigation before planting plus weeding emerged seedlings and, irrigation after sowing), and maize planting patterns (one-row and two-row planting of maize with same density per square of row length) that were assigned in a factorial arrangement to the sub plots. Soil samples were taken at the beginning of the season (before planting of maize) and at the end of the season (after harvest) at depth of 0-5 cm in the fixed quadrates (60 cm x 60 cm). The weed seeds were extracted from the soil samples and were identified using standard methods. The majority of weed seed bank populations included 6 weed species: Portulaca oleracea, Chenopodium album, Amaranthus retroflexus, Sorghum halepense, Daturea stramonium, Xanthium strumarium. Results showed that population of weed seed bank increased significantly with increasing nitrogen rate. The increasing rate was different between one-row and two-row planting patterns. The parameters indicated that seed bank population was much higher in a one row planting pattern of maize. With two-row planting, seed bank was decreased by 34, 26, 20 and 5% at 200, 300, 400 and 500 kg N/ha, respectively. Pre-planting irrigation was also found an effective implement to reduce the weed seed bank. When pre-planting irrigation was applied, seed bank was decreased by 57, 43, 34 and 9% at 200, 300, 400 and 500 kg N/ha. Increasing nitrogen because of weed's better growth and higher seed

  19. Root Border Cells and Their Role in Plant Defense.

    Science.gov (United States)

    Hawes, Martha; Allen, Caitilyn; Turgeon, B Gillian; Curlango-Rivera, Gilberto; Minh Tran, Tuan; Huskey, David A; Xiong, Zhongguo

    2016-08-01

    Root border cells separate from plant root tips and disperse into the soil environment. In most species, each root tip can produce thousands of metabolically active cells daily, with specialized patterns of gene expression. Their function has been an enduring mystery. Recent studies suggest that border cells operate in a manner similar to mammalian neutrophils: Both cell types export a complex of extracellular DNA (exDNA) and antimicrobial proteins that neutralize threats by trapping pathogens and thereby preventing invasion of host tissues. Extracellular DNases (exDNases) of pathogens promote virulence and systemic spread of the microbes. In plants, adding DNase I to root tips eliminates border cell extracellular traps and abolishes root tip resistance to infection. Mutation of genes encoding exDNase activity in plant-pathogenic bacteria (Ralstonia solanacearum) and fungi (Cochliobolus heterostrophus) results in reduced virulence. The study of exDNase activities in plant pathogens may yield new targets for disease control. PMID:27215971

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

    Directory of Open Access Journals (Sweden)

    Lima D.U.

    2001-01-01

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

  1. Polynucleotide phosphorylase from plant cells.

    Science.gov (United States)

    Schumacher-Wittkopf, E; Richter, G; Schulze, S

    1984-06-01

    The isolation of polynucleotide phosphorylase (EC 2. 7. 7. 8) from suspension cultured plant cells of parsley (Petroselinum sativum) and from tomato seedlings (Lycopersicon esculentum) is described. The procedure includes an ultracentrifugation step, a glycerol density gradient centrifugation and preparative gel electrophoresis under nondenaturing conditions. Isoelectric focusing gives rise to a major component (pI ≈ 7.5) and to a minor one (pI ≈ 5). The enzyme contains five subunits with apparent Mr values of 160 000, 140 000, 70 000, 34 000 and 12 000, the 70 000-dalton one being a glycoprotein. PMID:24253429

  2. Features and distribution patterns of Chinese endemic seed plant species

    Institute of Scientific and Technical Information of China (English)

    Ji-Hong HUANG; Jian-Hua CHEN; Jun-Sheng YING; Ke-Ping MA

    2011-01-01

    We compiled and identified a list of Chinese. endemic seed plant species based on a large number of published References and expert reviews. The characters of these seed plant species and their distribution patterns were described at length. China is rich in endemic seed plants, with a total of 14 939 species (accounting for 52.1%of its total seed plant species) belonging to 1584 genera and 191 families. Temperate families and genera have a significantly higher proportion of endemism than cosmopolitan and tropical ones. The most primitive and derived groups have significantly higher endemism than the other groups. The endemism of tree, shrub, and liana or vine is higher than that of total species; in contrast, the endemism of herb is lower than that of total species. Geographically,these Chinese endemic plants are mainly distributed in Yunnan and Sichuan provinces, southwest China. Species richness and proportion of these endemic plants decrease with increased latitude and have a unimodal response to altitude. The peak value of proportion of endemism is at higher altitudes than that of total species and endemic species richness. The proportions of endemic shrub, liana or vine, and herb increase with altitude and have a clear unimodal curve. In contrast, the proportion of tree increases with altitude, with a sudden increase at~4000 m and has a completely different model. To date, our study provides the most comprehensive list of Chinese endemic seed plant species and their basic composition and distribution features.

  3. Global response patterns of terrestrial plant species to nitrogen addition.

    Science.gov (United States)

    Xia, Jianyang; Wan, Shiqiang

    2008-07-01

    Better understanding of the responses of terrestrial plant species under global nitrogen (N) enrichment is critical for projection of changes in structure, functioning, and service of terrestrial ecosystems. Here, a meta-analysis of data from 304 studies was carried out to reveal the general response patterns of terrestrial plant species to the addition of N. Across 456 terrestrial plant species included in the analysis, biomass and N concentration were increased by 53.6 and 28.5%, respectively, under N enrichment. However, the N responses were dependent upon plant functional types, with significantly greater biomass increases in herbaceous than in woody species. Stimulation of plant biomass by the addition of N was enhanced when other resources were improved. In addition, the N responses of terrestrial plants decreased with increasing latitude and increased with annual precipitation. Dependence of the N responses of terrestrial plants on biological realms, functional types, tissues, other resources, and climatic factors revealed in this study can help to explain changes in species composition, diversity, community structure and ecosystem functioning under global N enrichment. These findings are critical in improving model simulation and projection of terrestrial carbon sequestration and its feedbacks to global climate change, especially when progressive N limitation is taken into consideration. PMID:19086179

  4. Plant caspase-like proteases in plant programmed cell death

    OpenAIRE

    Xu, Qixian; Zhang, Lingrui

    2009-01-01

    Programmed cell death (PCD) is a genetically-controlled disassembly of the cell. In animal systems, the central core execution switch for apoptotic PCD is the activation of caspases (Cysteine-containing Aspartate-specific proteases). Accumulating evidence in recent years suggests the existence of caspase-like activity in plants and its functional involvement in various types of plant PCD, although no functional homologs of animal caspases were identified in plant genome. In this mini-review, ...

  5. Photothermal nanoblade for patterned cell membrane cutting

    OpenAIRE

    Wu, Ting-Hsiang; Teslaa, Tara; Teitell, Michael A.; Chiou, Pei-Yu

    2010-01-01

    We report a photothermal nanoblade that utilizes a metallic nanostructure to harvest short laser pulse energy and convert it into a highly localized and specifically shaped explosive vapor bubble. Rapid bubble expansion and collapse punctures a lightly-contacting cell membrane via high-speed fluidic flows and induced transient shear stress. The membrane cutting pattern is controlled by the metallic nanostructure configuration, laser pulse polarization, and energy. Highly controllable, sub-mic...

  6. Effect of planting patterns of sunflower on yield and extinction coefficient

    OpenAIRE

    J. Zarea, Mohammad; Ghalavand, Amir; Daneshian, Jahanfar

    2005-01-01

    We studied the effect of different planting patterns and density of sunflower on yield and on extinction coefficient. The experiment was conducted in the field at the Seed and Plant Improvement Institute, Karaj, Iran on a loamy clay. Planting patterns included wide rows, conventional rows, twin rectangular rows and twin zigzag rows. Populations of plants were at 3 levels including 6, 8 and 10 plants per square meter. The results show that different planting patterns sometimes produced higher ...

  7. Plant Proteases Involved in Regulated Cell Death.

    Science.gov (United States)

    Zamyatnin, A A

    2015-12-01

    Each plant genome encodes hundreds of proteolytic enzymes. These enzymes can be divided into five distinct classes: cysteine-, serine-, aspartic-, threonine-, and metalloproteinases. Despite the differences in their structural properties and activities, members of all of these classes in plants are involved in the processes of regulated cell death - a basic feature of eukaryotic organisms. Regulated cell death in plants is an indispensable mechanism supporting plant development, survival, stress responses, and defense against pathogens. This review summarizes recent advances in studies of plant proteolytic enzymes functioning in the initiation and execution of distinct types of regulated cell death. PMID:26878575

  8. Refractive index of plant cell walls

    Science.gov (United States)

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

    1974-01-01

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

  9. Regulation of cell division in higher plants. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, T.W.

    1992-07-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant`s essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  10. Plant stem cells as innovation in cosmetics.

    Science.gov (United States)

    Moruś, Martyna; Baran, Monika; Rost-Roszkowska, Magdalena; Skotnicka-Graca, Urszula

    2014-01-01

    The stem cells thanks to their ability of unlimited division number or transformation into different cell types creating organs, are responsible for regeneration processes. Depending on the organism in which the stem cells exists, they divide to the plant or animal ones. The later group includes the stem cells existing in both embryo's and adult human's organs. It includes, among others, epidermal stem cells, located in the hair follicle relieves and also in its basal layers, and responsible for permanent regeneration of the epidermis. Temporary science looks for method suitable for stimulation of the epidermis stem cells, amongst the other by delivery of e.g., growth factors for proliferation that decrease with the age. One of the methods is the use of the plant cell culture technology, including a number of methods that should ensure growth of plant cells, issues or organs in the environment with the microorganism-free medium. It uses abilities of the different plant cells to dedifferentiation into stem cells and coming back to the pluripotent status. The extracts obtained this way from the plant stem cells are currently used for production of both common or professional care cosmetics. This work describes exactly impact of the plant stem cell extract, coming from one type of the common apple tree (Uttwiler Spätlauber) to human skin as one of the first plant sorts, which are used in cosmetology and esthetic dermatology. PMID:25362798

  11. Isotope pattern deconvolution as a tool to study iron metabolism in plants

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Castrillon, Jose A.; Moldovan, Mariella; Garcia Alonso, J.I. [University of Oviedo, Department of Physical and Analytical Chemistry, Oviedo (Spain); Lucena, Juan J.; Garcia-Tome, Maria L.; Hernandez-Apaolaza, Lourdes [Autonoma University of Madrid, Department of Agricultural Chemistry, Madrid (Spain)

    2008-01-15

    Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using {sup 57}Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned {sup 57}Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low {sup 57}Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of {sup 57}Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample. (orig.)

  12. Predictable patterns of trait mismatches between interacting plants and insects

    Directory of Open Access Journals (Sweden)

    Ellis Allan G

    2010-07-01

    Full Text Available Abstract Background There are few predictions about the directionality or extent of morphological trait (mismatches between interacting organisms. We review and analyse studies on morphological trait complementarity (e.g. floral tube length versus insect mouthpart length at the population and species level. Results Plants have consistently more exaggerated morphological traits than insects at high trait magnitudes and in some cases less exaggerated traits than insects at smaller trait magnitudes. This result held at the population level, as well as for phylogenetically adjusted analyses at the species-level and for both pollination and host-parasite interactions, perhaps suggesting a general pattern. Across communities, the degree of trait mismatch between one specialist plant and its more generalized pollinator was related to the level of pollinator specialization at each site; the observed pattern supports the "life-dinner principle" of selection acting more strongly on species with more at stake in the interaction. Similarly, plant mating system also affected the degree of trait correspondence because selfing reduces the reliance on pollinators and is analogous to pollination generalization. Conclusions Our analyses suggest that there are predictable "winners" and "losers" of evolutionary arms races and the results of this study highlight the fact that breeding system and the degree of specialization can influence the outcome.

  13. A knowledge based method for nuclear plant loading pattern determination

    International Nuclear Information System (INIS)

    This paper deals with the design of a knowledge based system for solving an industrial problem which occurs in nuclear fuel management. The problem lies in determining satisfactory loading patterns for nuclear plants. Its primary feature consists in the huge search space involved. Conventional resolution processes are formally defined and analyzed: there is no general algorithm which guarantees to always provide a reasonable solution in each situation. We propose a new approach to solve this constrained search problem using domain-specific knowledge and general constraint-based heuristics. During a preprocessing step, a problem dependent search algorithm is designed. This procedure is then automatically implemented in FORTRAN. The generated routines have proved to be very efficient finding solutions which could not have been provided using logic programming. A prototype expert system has already been applied to actual reload pattern searches. While combining efficiency and flexibility, this knowledge based system enables human experts to rapidly match new constraints and requirements

  14. Auxin regulation of cell polarity in plants.

    Science.gov (United States)

    Pan, Xue; Chen, Jisheng; Yang, Zhenbiao

    2015-12-01

    Auxin is well known to control pattern formation and directional growth at the organ/tissue levels via the nuclear TIR1/AFB receptor-mediated transcriptional responses. Recent studies have expanded the arena of auxin actions as a trigger or key regulator of cell polarization and morphogenesis. These actions require non-transcriptional responses such as changes in the cytoskeleton and vesicular trafficking, which are commonly regulated by ROP/Rac GTPase-dependent pathways. These findings beg for the question about the nature of auxin receptors that regulate these responses and renew the interest in ABP1 as a cell surface auxin receptor, including the work showing auxin-binding protein 1 (ABP1) interacts with the extracellular domain of the transmembrane kinase (TMK) receptor-like kinases in an auxin-dependent manner, as well as the debate on this auxin binding protein discovered about 40 years ago. This review highlights recent work on the non-transcriptional auxin signaling mechanisms underscoring cell polarity and shape formation in plants. PMID:26599954

  15. Microtubule networks for plant cell division

    NARCIS (Netherlands)

    Keijzer, de Jeroen; Mulder, B.M.; Janson, M.E.

    2014-01-01

    During cytokinesis the cytoplasm of a cell is divided to form two daughter cells. In animal cells, the existing plasma membrane is first constricted and then abscised to generate two individual plasma membranes. Plant cells on the other hand divide by forming an interior dividing wall, the so-called

  16. Plant architecture without multicellularity: quandaries over patterning and the soma-germline divide in siphonous algae

    Directory of Open Access Journals (Sweden)

    Viktoriya eConeva

    2015-04-01

    Full Text Available Multicellularity has independently evolved numerous times throughout the major lineages of life. Often, multicellularity can enable complex, macroscopic organismal architectures but it is not required for the elaboration of morphology. Several alternative cellular strategies have arisen as solutions permitting exquisite forms. The green algae class Ulvophyceae, for example, contains truly multicellular organisms, as well as macroscopic siphonous cells harboring one or multiple nuclei, and siphonocladous species, which are multinucleate and multicellular. These diverse cellular organizations raise a number of questions about the evolutionary and molecular mechanisms underlying complex organismal morphology in the green plants. Importantly, how does morphological patterning arise in giant coenocytes, and do nuclei, analogous to cells in multicellular organisms, take on distinct somatic and germline identities? Here, we comparatively explore examples of patterning and differentiation in diverse coenocytic and single-cell organisms and discuss possible mechanisms of development and nuclear differentiation in the siphonous algae.

  17. Patterns of plant diversity and endemism in Namibia

    Directory of Open Access Journals (Sweden)

    P. Craven

    2006-12-01

    Full Text Available Species richness, endemism and areas that are rich in both species and endemic species were assessed and mapped for Namibia. High species diversity corresponds with zones where species overlap. These are particularly obvious where there are altitudinal variations and in high-lying areas. The endemic flora of Namibia is rich and diverse. An estimated 16% of the total plant species in Namibia are endemic to the country. Endemics are in a wide variety of families and sixteen genera are endemic. Factors that increase the likelihood of endemism are mountains, hot deserts, diversity of substrates and microclimates. The distribution of plants endemic to Namibia was arranged in three different ways. Firstly, based on a grid count with the phytogeographic value o f the species being equal, overall endemism was mapped. Secondly, range restricted plant species were mapped individually and those with congruent distribution patterns were combined. Thirdly, localities that are important for very range-restricted species were identified. The resulting maps o f endemism and diversity were compared and found to correspond in many localities. When overall endemism is compared with overall diversity, rich localities may consist of endemic species with wide ranges. The other methods identify important localities with their own distinctive complement of species.

  18. The plant actin cytoskeleton responds to signals from microbe-associated molecular patterns.

    Directory of Open Access Journals (Sweden)

    Jessica L Henty-Ridilla

    Full Text Available Plants are constantly exposed to a large and diverse array of microbes; however, most plants are immune to the majority of potential invaders and susceptible to only a small subset of pathogens. The cytoskeleton comprises a dynamic intracellular framework that responds rapidly to biotic stresses and supports numerous fundamental cellular processes including vesicle trafficking, endocytosis and the spatial distribution of organelles and protein complexes. For years, the actin cytoskeleton has been assumed to play a role in plant innate immunity against fungi and oomycetes, based largely on static images and pharmacological studies. To date, however, there is little evidence that the host-cell actin cytoskeleton participates in responses to phytopathogenic bacteria. Here, we quantified the spatiotemporal changes in host-cell cytoskeletal architecture during the immune response to pathogenic and non-pathogenic strains of Pseudomonas syringae pv. tomato DC3000. Two distinct changes to host cytoskeletal arrays were observed that correspond to distinct phases of plant-bacterial interactions i.e. the perception of microbe-associated molecular patterns (MAMPs during pattern-triggered immunity (PTI and perturbations by effector proteins during effector-triggered susceptibility (ETS. We demonstrate that an immediate increase in actin filament abundance is a conserved and novel component of PTI. Notably, treatment of leaves with a MAMP peptide mimic was sufficient to elicit a rapid change in actin organization in epidermal cells, and this actin response required the host-cell MAMP receptor kinase complex, including FLS2, BAK1 and BIK1. Finally, we found that actin polymerization is necessary for the increase in actin filament density and that blocking this increase with the actin-disrupting drug latrunculin B leads to enhanced susceptibility of host plants to pathogenic and non-pathogenic bacteria.

  19. System Studies of Fuel Cell Power Plants

    OpenAIRE

    Kivisaari, Timo

    2001-01-01

    This thesis concerns system studies of power plants wheredifferent types of fuel cells accomplish most of the energyconversion. Ever since William Grove observed the fuel cell effect inthe late 1830s fuel cells have been the subject or more or lessintense research and development. Especially in the USA theseactivities intensified during the second part of the 1950s,resulting in the development of the fuel cells used in theApollo-program. Swedish fuel cell activities started in themid-1960s, w...

  20. Plant cell cultures and their biotechnological potential

    Energy Technology Data Exchange (ETDEWEB)

    Barz, W.; Ellis, B.E.

    1981-01-01

    The potential of plant cell suspension cultures for the biotechnological production of high-cost, plant-specific compounds is critically evaluated. The basic roles of nutrient media and phytohormones are described followed by a description of the recent progress in mass cultivation of plant cell cultures as measured by biomass and doubling time. The accumulation of secondary constituents in cell cultures is reviewed and methods for the selection of high-producing strains are described. The essential features of the selection strategy are the establishment of cell cultures from high-producing plants and a sensitive assay (e.g. radio-immunoassay) for the screening of microcolonies grown on petri dishes. The accumulation of biosynthetic intermediates of secondary constituents in cell culture strains will possibly lead to the isolation of novel compounds.

  1. Electron Tomography in Plant Cell Biology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This review focuses on the contribution of electron tomography-based techniques to our understanding of cellular processes in plant cells. Electron microscopy techniques have evolved to provide better three-dimensional resolution and improved preservation of the subcellular components. In particular, the combination of cryofixation/freeze substitution and electron tomography have allowed plant cell biologists to image organelles and macromolecular complexes in their native cellular context with unprecedented three-dimensional resolution (4-7 nm). Until now, electron tomography has been applied in plant cell biology for the study of cytokinesis, Golgi structure and trafficking, formation of plant endosome/prevacuolar compartments, and organization of photosynthetic membranes. We discuss in this review the new insights that these tomographic studies have brought to the plant biology field.

  2. Inducible cell death in plant immunity

    DEFF Research Database (Denmark)

    Hofius, Daniel; Tsitsigiannis, Dimitrios I; Jones, Jonathan D G;

    2006-01-01

    Programmed cell death (PCD) occurs during vegetative and reproductive plant growth, as typified by autumnal leaf senescence and the terminal differentiation of the endosperm of cereals which provide our major source of food. PCD also occurs in response to environmental stress and pathogen attack......, and these inducible PCD forms are intensively studied due their experimental tractability. In general, evidence exists for plant cell death pathways which have similarities to the apoptotic, autophagic and necrotic forms described in yeast and metazoans. Recent research aiming to understand these...... pathways and their molecular components in plants are reviewed here....

  3. Mass spectrometry for characterizing plant cell wall polysaccharides

    Directory of Open Access Journals (Sweden)

    Stefan eBauer

    2012-03-01

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

  4. Pattern formation in a cell based auxin transport model with numerical bifurcation analysis

    CERN Document Server

    Draelants, Delphine; Beemster, Gerrit T S; Vanroose, Wim

    2012-01-01

    Transport models of growth hormones can be used to reproduce the hormone accumulations that occur in plant organs. Mostly, these accumulation patterns are calculated using time step methods, even though only the resulting steady state patterns of the model are of interest. We examine the steady state solutions of the hormone transport model of Smith et al (2006) for a one-dimensional row of plant cells. We search for the steady state solutions as a function of three of the model parameters by using numerical continuation methods and bifurcation analysis. These methods are more adequate for solving steady state problems than time step methods. We discuss a trivial solution where the concentrations of hormones are equal in all cells and examine its stability region. We identify two generic bifurcation scenarios through which the trivial solution loses its stability. The trivial solution becomes either a steady state pattern with regular spaced peaks or a pattern where the concentration is periodic in time.

  5. Quantification of plant cell coupling with live-cell microscopy

    DEFF Research Database (Denmark)

    Liesche, Johannes; Schulz, Alexander

    2015-01-01

    Movement of nutrients and signaling compounds from cell to cell is an essential process for plant growth and development. To understand processes such as carbon allocation, cell communication, and reaction to pathogen attack it is important to know a specific molecule’s capacity to pass a specific...... cell wall interface. Transport through plasmodesmata, the cell wall channels that directly connect plant cells, is regulated not only by a fixed size exclusion limit, but also by physiological and pathological adaptation. The noninvasive approach described here offers the possibility of precisely...... determining the plasmodesmata-mediated cell wall permeability for small molecules in living cells. The method is based on photoactivation of the fluorescent tracer caged fluorescein. Non-fluorescent caged fluorescein is applied to a target tissue, where it is taken up passively into all cells. Imaged by...

  6. Microtubule networks for plant cell division.

    Science.gov (United States)

    de Keijzer, Jeroen; Mulder, Bela M; Janson, Marcel E

    2014-09-01

    During cytokinesis the cytoplasm of a cell is divided to form two daughter cells. In animal cells, the existing plasma membrane is first constricted and then abscised to generate two individual plasma membranes. Plant cells on the other hand divide by forming an interior dividing wall, the so-called cell plate, which is constructed by localized deposition of membrane and cell wall material. Construction starts in the centre of the cell at the locus of the mitotic spindle and continues radially towards the existing plasma membrane. Finally the membrane of the cell plate and plasma membrane fuse to form two individual plasma membranes. Two microtubule-based cytoskeletal networks, the phragmoplast and the pre-prophase band (PPB), jointly control cytokinesis in plants. The bipolar microtubule array of the phragmoplast regulates cell plate deposition towards a cortical position that is templated by the ring-shaped microtubule array of the PPB. In contrast to most animal cells, plants do not use centrosomes as foci of microtubule growth initiation. Instead, plant microtubule networks are striking examples of self-organizing systems that emerge from physically constrained interactions of dispersed microtubules. Here we will discuss how microtubule-based activities including growth, shrinkage, severing, sliding, nucleation and bundling interrelate to jointly generate the required ordered structures. Evidence mounts that adapter proteins sense the local geometry of microtubules to locally modulate the activity of proteins involved in microtubule growth regulation and severing. Many of the proteins and mechanisms involved have roles in other microtubule assemblies as well, bestowing broader relevance to insights gained from plants. PMID:25136380

  7. Carbon isotope ratios in crassulacean Acid metabolism plants: seasonal patterns from plants in natural stands.

    Science.gov (United States)

    Szarek, S R

    1976-09-01

    A year round study of photosynthesis and carbon isotope fractionation was conducted with plants of Opuntia phaeacantha Engelm. and Yucca baccata Torr. occurring in natural stands at elevations of 525, 970, 1450 and 1900 m. Plant water potentials and the daytime pattern of (14)CO(2) photosynthesis were similar for all cacti along the elevational gradient, despite significant differences in temperature regime and soil water status. Carbon isotope ratios of total tissue and soluble extract fractions were relatively constant throughtout the entire year. Additionally, the sigma(13)C values were similar in all plants of the same species along the elevational gradient, i.e. -12.5 +/- 0.86 per thousand for O. phaeacantha and -15.7 +/- 0.95 per thousand for Y. baccata. The results of this study indicate Crassulacean acid metabolism predominates as the major carbon pathway of these plants, which do not facultatively utilize the reductive pentose phosphate cycle of photosynthesis as the primary carboxylation reaction. PMID:16659680

  8. Early embryogenesis in flowering plants: setting up the basic body pattern.

    Science.gov (United States)

    Lau, Steffen; Slane, Daniel; Herud, Ole; Kong, Jixiang; Jürgens, Gerd

    2012-01-01

    Early embryogenesis is the critical developmental phase during which the basic features of the plant body are established: the apical-basal axis of polarity, different tissue layers, and both the root pole and the shoot pole. Polarization of the zygote correlates with the generation of apical and basal (embryonic and extraembryonic) cell fates. Whereas mechanisms of zygote polarization are still largely unknown, distinct expression domains of WOX family transcription factors as well as directional auxin transport and local auxin response are known to be involved in early apical-basal patterning. Radial patterning of tissue layers appears to be mediated by cell-cell communication involving both peptide signaling and transcription factor movement. Although the initiation of the shoot pole is still unclear, the apical organization of the embryo depends on both the proper establishment of transcription factor expression domains and, for cotyledon initiation, upward auxin flow in the protoderm. Here we focus on the essential patterning processes, drawing mainly on data from Arabidopsis thaliana and also including relevant data from other species if available. PMID:22224452

  9. Laser-mediated perforation of plant cells

    Science.gov (United States)

    Wehner, Martin; Jacobs, Philipp; Esser, Dominik; Schinkel, Helga; Schillberg, Stefan

    2007-07-01

    The functional analysis of plant cells at the cellular and subcellular levels requires novel technologies for the directed manipulation of individual cells. Lasers are increasingly exploited for the manipulation of plant cells, enabling the study of biological processes on a subcellular scale including transformation to generate genetically modified plants. In our setup either a picosecond laser operating at 1064 nm wavelength or a continuous wave laser diode emitting at 405 nm are coupled into an inverse microscope. The beams are focused to a spot size of about 1.5 μm and the tobacco cell protoplasts are irradiated. Optoporation is achieved when targeting the laser focal spot at the outermost edge of the plasma membrane. In case of the picosecond laser a single pulse with energy of about 0.4 μJ was sufficient to perforate the plasma membrane enabling the uptake of dye or DNA from the surrounding medium into the cytosol. When the ultraviolet laser diode at a power level of 17 mW is employed an irradiation time of 200 - 500 milliseconds is necessary to enable the uptake of macromolecules. In the presence of an EYFP encoding plasmid with a C-terminal peroxisomal signal sequence in the surrounding medium transient transformation of tobacco protoplasts could be achieved in up to 2% of the optoporated cells. Single cell perforation using this novel optoporation method shows that isolated plant cells can be permeabilized without direct manipulation. This is a valuable procedure for cell-specific applications, particularly where the import of specific molecules into plant cells is required for functional analysis.

  10. Characterization of Cellulose Synthesis in Plant Cells

    OpenAIRE

    Samaneh Sadat Maleki; Kourosh Mohammadi; Kong-shu Ji

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the...

  11. Plant Cell Lines in Cell Morphogenesis Research

    Czech Academy of Sciences Publication Activity Database

    Seifertová, Daniela; Klíma, Petr; Pařezová, Markéta; Petrášek, Jan; Zažímalová, Eva; Opatrný, Z.

    Vol. 1080. New York: Humana Press, 2014 - (Žárský, V.; Cvrčková, F.), s. 215-229. (Methods in Molecular Biology). ISBN 978-1-62703-643-6 R&D Projects: GA ČR(CZ) GAP305/11/0797; GA ČR(CZ) GAP305/11/2476 Institutional support: RVO:61389030 Keywords : BY-2 * VBI-0 * Suspension-cultured cells Subject RIV: EB - Genetics ; Molecular Biology

  12. YIELD AND GRADE OF VALENCIA PEANUT IN SINGLE ROW, TWIN ROW, AND DIAMOND PLANTING PATTERNS

    Science.gov (United States)

    A study was conducted at Wayne Baker’s farm South of Clovis in 2006 to compare single row, twin row, and diamond planting patterns in Valencia peanut on 36 inch beds. The twin row and diamond pattern treatments were planted with an experimental planter developed at the USDA-ARS National Peanut Rese...

  13. Endothelial cell motility, coordination and pattern formation during vasculogenesis.

    Science.gov (United States)

    Czirok, Andras

    2013-01-01

    How vascular networks assemble is a fundamental problem of developmental biology that also has medical importance. To explain the organizational principles behind vascular patterning, we must understand how can tissue level structures be controlled through cell behavior patterns like motility and adhesion that, in turn, are determined by biochemical signal transduction processes? We discuss the various ideas that have been proposed as mechanisms for vascular network assembly: cell motility guided by extracellular matrix alignment (contact guidance), chemotaxis guided by paracrine and autocrine morphogens, and multicellular sprouting guided by cell-cell contacts. All of these processes yield emergent patterns, thus endothelial cells can form an interconnected structure autonomously, without guidance from an external pre-pattern. PMID:23857825

  14. FRACTAL DIMENSIONS FOR RADIOISOTOPE POLLUTION PATTERNS BY NUCLEAR POWER PLANT ACCIDENTS

    OpenAIRE

    Saito, K.; Ogawa, S.

    2015-01-01

    The radioisotope pollution shows two types of patterns: dry and wet deposits for nuclear power plant accidents. Two surface pollution patterns were analysed by fractal. In Fukushima nuclear power plant accident, surface pollution by wet deposits was estimated to occur. However, actually it was no rain and white crystals were observed on the surface. Then, fractal analysis was carried out for the spatial distribution patterns of radio isotopes on the surface to judge the types of depo...

  15. Direct FuelCell/Turbine Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hossein Ghezel-Ayagh

    2008-09-30

    This report summarizes the progress made in development of Direct FuelCell/Turbine (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T system employs an indirectly heated Turbine Generator to supplement fuel cell generated power. The concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design, direct reforming internal to the fuel cell, and potential cost competitiveness with existing combined cycle power plants. Proof-of-concept tests using a sub-MW-class DFC/T power plant at FuelCell Energy's (FCE) Danbury facility were conducted to validate the feasibility of the concept and to measure its potential for electric power production. A 400 kW-class power plant test facility was designed and retrofitted to conduct the tests. The initial series of tests involved integration of a full-size (250 kW) Direct FuelCell stack with a 30 kW Capstone microturbine. The operational aspects of the hybrid system in relation to the integration of the microturbine with the fuel cell, process flow and thermal balances, and control strategies for power cycling of the system, were investigated. A subsequent series of tests included operation of the sub-MW Direct FuelCell/Turbine power plant with a Capstone C60 microturbine. The C60 microturbine extended the range of operation of the hybrid power plant to higher current densities (higher power) than achieved in initial tests using the 30kW microturbine. The proof-of-concept test results confirmed the stability and controllability of operating a fullsize (250 kW) fuel cell stack in combination with a microturbine. Thermal management of the system was confirmed and power plant operation, using the microturbine as the only source of fresh air supply

  16. Thermodynamics of irreversible plant cell growth

    Directory of Open Access Journals (Sweden)

    Mariusz Pietruszka

    2011-04-01

    Full Text Available The time-irreversible cell enlargement of plant cells at a constant temperature results from two independent physical processes, e.g. water absorption and cell wall yielding. In such a model cell growth starts with reduction in wall stress because of irreversible extension of the wall. The water absorption and physical expansion are spontaneous consequences of this initial modification of the cell wall (the juvenile cell vacuolate, takes up water and expands. In this model the irreversible aspect of growth arises from the extension of the cell wall. Such theory expressed quantitatively by time-dependent growth equation was elaborated by Lockhart in the 60's.The growth equation omit however a very important factor, namely the environmental temperature at which the plant cells grow. In this paper we put forward a simple phenomenological model which introduces into the growth equation the notion of temperature. Moreover, we introduce into the modified growth equation the possible influence of external growth stimulator or inhibitor (phytohormones or abiotic factors. In the presence of such external perturbations two possible theoretical solutions have been found: the linear reaction to the application of growth hormones/abiotic factors and the non-linear one. Both solutions reflect and predict two different experimental conditions, respectively (growth at constant or increasing concentration of stimulator/inhibitor. The non-linear solution reflects a common situation interesting from an environmental pollution point of view e.g. the influence of increasing (with time concentration of toxins on plant growth. Having obtained temperature modified growth equations we can draw further qualitative and, especially, quantitative conclusions about the mechanical properties of the cell wall itself. This also concerns a new and interesting result obtained in our model: We have calculated the magnitude of the cell wall yielding coefficient (T [m3 J-1•s-1] in

  17. Surface Functionalization for Protein and Cell Patterning

    Science.gov (United States)

    Colpo, Pascal; Ruiz, Ana; Ceriotti, Laura; Rossi, François

    The interaction of biological systems with synthetic material surfaces is an important issue for many biological applications such as implanted devices, tissue engineering, cell-based sensors and assays, and more generally biologic studies performed ex vivo. To ensure reliable outcomes, the main challenge resides in the ability to design and develop surfaces or artificial micro-environment that mimic 'natural environment' in interacting with biomolecules and cells without altering their function and phenotype. At this effect, microfabrication, surface chemistry and material science play a pivotal role in the design of advanced in-vitro systems for cell culture applications. In this chapter, we discuss and describe different techniques enabling the control of cell-surface interactions, including the description of some techniques for immobilization of ligands for controlling cell-surface interactions and some methodologies for the creation of well confined cell rich areas.

  18. Integrating transcriptional controls for plant cell expansion

    OpenAIRE

    Mockaitis, Keithanne; Estelle, Mark

    2004-01-01

    The plant hormones auxin and brassinosteroid promote cell expansion by regulating gene expression. In addition to independent transcriptional responses generated by the two signals, recent microarray analyses indicate that auxin and brassinosteroid also coordinate the expression of a set of shared target genes.

  19. Can inducible resistance in plants cause herbivore aggregations? Spatial patterns in an inducible plant/herbivore model.

    Science.gov (United States)

    Anderson, Kurt E; Inouye, Brian D; Underwood, Nora

    2015-10-01

    Many theories regarding the evolution of inducible resistance in plants have an implicit spatial component, but most relevant population dynamic studies ignore spatial dynamics. We examined a spatially explicit model of plant inducible resistance and herbivore population dynamics to explore how realistic features of resistance and herbivore responses influence spatial patterning. Both transient and persistent spatial patterns developed in all models examined, where patterns manifested as wave-like aggregations of herbivores and variation in induction levels. Patterns arose when herbivores moved away from highly induced plants, there was a lag between damage and deployment of induced resistance, and the relationship between herbivore density and strength of the induction response had a sigmoid shape. These mechanisms influenced pattern formation regardless of the assumed functional relationship between resistance and herbivore recruitment and mortality. However, in models where induction affected herbivore mortality, large-scale herbivore population cycles driven by the mortality response often co-occurred with smaller scale spatial patterns driven by herbivore movement. When the mortality effect dominated, however, spatial pattern formation was completely replaced by spatially synchronized herbivore population cycles. Our results present a new type of ecological pattern formation driven by induced trait variation, consumer behavior, and time delays that has broad implications for the community and evolutionary ecology of plant defenses. PMID:26649396

  20. Quantification of plant cell coupling with live-cell microscopy

    DEFF Research Database (Denmark)

    Liesche, Johannes; Schulz, Alexander

    cell wall interface. Transport through plasmodesmata, the cell wall channels that directly connect plant cells, is regulated not only by a fixed size exclusion limit, but also by physiological and pathological adaptation. The noninvasive approach described here offers the possibility of precisely...... confocal microscopy, loaded tracer is activated by UV illumination in a target cell and its spread to neighboring cells monitored. When combined with high-speed acquisition by resonant scanning or spinning disc confocal microscopy, the high signal-to-noise ratio of photoactivation allows collection of...

  1. Pathogen infection drives patterns of nutrient resorption in citrus plants

    OpenAIRE

    Jirong Cao; Chunzhen Cheng; Junjie Yang; Qibing Wang

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen ‘Candidatus Liberibacter asiaticus’ grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of ‘Ca. L. asiaticus’ infection on nit...

  2. Macroecological and macroevolutionary patterns of leaf herbivory across vascular plants

    OpenAIRE

    Turcotte, Martin M.; Davies, T. Jonathan; Thomsen, Christina J. M.; Johnson, Marc T. J.

    2014-01-01

    The consumption of plants by animals underlies important evolutionary and ecological processes in nature. Arthropod herbivory evolved approximately 415 Ma and the ensuing coevolution between plants and herbivores is credited with generating much of the macroscopic diversity on the Earth. In contemporary ecosystems, herbivory provides the major conduit of energy from primary producers to consumers. Here, we show that when averaged across all major lineages of vascular plants, herbivores consum...

  3. Resource competition in plant invasions: emerging patterns and research needs

    OpenAIRE

    Margherita eGioria; Bruce Arthur Osborne

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relatively to that of other mechanisms, at different stages of an invasion ...

  4. Resource competition in plant invasions: emerging patterns and research needs

    OpenAIRE

    Gioria, Margherita; Osborne, Bruce A.

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion pr...

  5. Glycoprotein component of plant cell walls

    International Nuclear Information System (INIS)

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

  6. Self-organizing actomyosin patterns on the cell cortex at epithelial cell-cell junctions.

    Science.gov (United States)

    Moore, Thomas; Wu, Selwin K; Michael, Magdalene; Yap, Alpha S; Gomez, Guillermo A; Neufeld, Zoltan

    2014-12-01

    The behavior of actomyosin critically determines morphologically distinct patterns of contractility found at the interface between adherent cells. One such pattern is found at the apical region (zonula adherens) of cell-cell junctions in epithelia, where clusters of the adhesion molecule E-cadherin concentrate in a static pattern. Meanwhile, E-cadherin clusters throughout lateral cell-cell contacts display dynamic movements in the plane of the junctions. To gain insight into the principles that determine the nature and organization of these dynamic structures, we analyze this behavior by modeling the 2D actomyosin cell cortex as an active fluid medium. The numerical simulations show that the stability of the actin filaments influences the spatial structure and dynamics of the system. We find that in addition to static Turing-type patterns, persistent dynamic behavior occurs in a wide range of parameters. In the 2D model, mechanical stress-dependent actin breakdown is shown to produce a continuously changing network of actin bridges, whereas with a constant breakdown rate, more isolated clusters of actomyosin tend to form. The model qualitatively reproduces the dynamic and stable patterns experimentally observed at the junctions between epithelial cells. PMID:25468344

  7. Endothelial cell motility, coordination and pattern formation during vasculogenesis

    OpenAIRE

    Czirok, Andras

    2013-01-01

    How vascular networks assemble is a fundamental problem of developmental biology that also has medical importance. To explain the organizational principles behind vascular patterning, we must understand how can tissue level structures be controlled through cell behavior patterns like motility and adhesion that, in turn, are determined by biochemical signal transduction processes? We discuss the various ideas that have been proposed as mechanisms for vascular network assembly: cell motility gu...

  8. Pathogen infection drives patterns of nutrient resorption in citrus plants.

    Science.gov (United States)

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen 'Candidatus Liberibacter asiaticus' grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of 'Ca. L. asiaticus' infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB. PMID:26419510

  9. Responses of Winter Wheat Yield and Water Use Efficiency to Irrigation Frequency and Planting Pattern

    Science.gov (United States)

    Bian, Chengyue; Ma, Changjian; Liu, Xinhui; Gao, Chao; Liu, Quanru; Yan, Zhenxing; Ren, Yujie; Li, Quanqi

    2016-01-01

    A suitable planting pattern and irrigation strategy are essential for optimizing winter wheat yield and water use efficiency (WUE). The study aimed to evaluate the impact of planting pattern and irrigation frequency on grain yield and WUE of winter wheat. During the 2013–2014 and 2014–2015 winter wheat growing seasons in the North China Plain, the effects of planting patterns and irrigation frequencies were determined on tiller number, grain yield, and WUE. The two planting patterns tested were wide-precision and conventional-cultivation. Each planting pattern had three irrigation regimes: irrigation (120 mm) at the jointing stage; irrigation (60 mm) at both the jointing and heading stages; and irrigation (40 mm) at the jointing, heading, and milking stages. In our study, tiller number was significantly higher in the wide-precision planting pattern than in the conventional-cultivation planting pattern. Additionally, the highest grain yields and WUE were observed when irrigation was applied at the jointing stage (120 mm) or at the jointing and heading stages (60 mm each) in the wide-precision planting pattern. These results could be attributed to higher tiller numbers as well as reduced water consumption due to reduced irrigation frequency. In both growing seasons, applying 60 mm of water at jointing and heading stages resulted in the highest grain yield among the treatments. Based on our results, for winter wheat production in semi-humid regions, we recommend a wide-precision planting pattern with irrigation (60 mm) at both the jointing and heading stages. PMID:27171202

  10. Direct FuelCell/Turbine Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hossein Ghezel-Ayagh

    2008-09-30

    This report summarizes the progress made in development of Direct FuelCell/Turbine (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T system employs an indirectly heated Turbine Generator to supplement fuel cell generated power. The concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design, direct reforming internal to the fuel cell, and potential cost competitiveness with existing combined cycle power plants. Proof-of-concept tests using a sub-MW-class DFC/T power plant at FuelCell Energy's (FCE) Danbury facility were conducted to validate the feasibility of the concept and to measure its potential for electric power production. A 400 kW-class power plant test facility was designed and retrofitted to conduct the tests. The initial series of tests involved integration of a full-size (250 kW) Direct FuelCell stack with a 30 kW Capstone microturbine. The operational aspects of the hybrid system in relation to the integration of the microturbine with the fuel cell, process flow and thermal balances, and control strategies for power cycling of the system, were investigated. A subsequent series of tests included operation of the sub-MW Direct FuelCell/Turbine power plant with a Capstone C60 microturbine. The C60 microturbine extended the range of operation of the hybrid power plant to higher current densities (higher power) than achieved in initial tests using the 30kW microturbine. The proof-of-concept test results confirmed the stability and controllability of operating a fullsize (250 kW) fuel cell stack in combination with a microturbine. Thermal management of the system was confirmed and power plant operation, using the microturbine as the only source of fresh air supply

  11. Ultrasonographic Pattern of Testicular Metastasis of Clear Cell Renal Cell Carcinoma with Pathological Correlation

    OpenAIRE

    Libert, Florent; Cabri-Wiltzer, Mathieu; Dardenne, Emmanuel; Draguet, Anne-Philippe; Puttemans, Thierry

    2016-01-01

    Two cases of testicular metastases of a clear cell renal cell carcinoma sharing a very similar ultrasonographic pattern are reported. The observed pattern – masses containing multiple tiny cyst-like areas – is very similar to that of a previously described ovarian metastasis of clear cell renal parenchymal tumor and can be explained by histopathologic features. Despite the small number of cases, this ultrasonographic pattern of testicular mass may be specific for metastasis of clear cell rena...

  12. Resource competition in plant invasions: emerging patterns and research needs

    Czech Academy of Sciences Publication Activity Database

    Gioria, Margherita; Osborne, B. A.

    2014-01-01

    Roč. 5, č. 501 (2014), s. 1-21. ISSN 1664-462X Institutional support: RVO:67985939 Keywords : plant invoasions * resource competition * dominance Subject RIV: EF - Botanics Impact factor: 3.948, year: 2014

  13. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  14. Characterization of Cellulose Synthesis in Plant Cells.

    Science.gov (United States)

    Maleki, Samaneh Sadat; Mohammadi, Kourosh; Ji, Kong-Shu

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family. PMID:27314060

  15. Comprehensive analysis of circadian periodic pattern in plant transcriptome

    OpenAIRE

    Ptitsyn Andrey

    2008-01-01

    Abstract Background Circadian rhythm is a crucial factor in orchestration of plant physiology, keeping it in synchrony with the daylight cycle. Previous studies have reported that up to 16% of plant transcriptome are circadially expressed. Results Our studies of mammalian gene expression revealed circadian baseline oscillation in nearly 100% of genes. Here we present a comprehensive analysis of periodicity in two independent data sets. Application of the advanced algorithms and analytic appro...

  16. Ecological Patterns and Processes in Sarracenia Carnivorous Pitcher Plant Fungi

    OpenAIRE

    Boynton, Primrose

    2012-01-01

    The kingdom Fungi is taxonomically and ecologically diverse, containing an estimated 1.5 million species. Fungi include decomposers, pathogens, and plant and animal mutualists. Many fungi are microorganisms, and the processes shaping microbial diversity may be fundamentally different from those that shape plants and animals. However, ecologists do not yet fully understand how fungal species are distributed over space and time. Using fungi that inhabit the water of Sarracenia carnivorous pitch...

  17. Autonomous patterning of cells on microstructured fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Iwori, E-mail: takeda-iwori@ed.tmu.ac.jp; Kawanabe, Masato, E-mail: kawanabe-masato@ed.tmu.ac.jp; Kaneko, Arata, E-mail: kaneko-arata@tmu.ac.jp

    2015-05-01

    Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO{sub 2} particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing.

  18. Plant cell technologies in space: Background, strategies and prospects

    Science.gov (United States)

    Kirkorian, A. D.; Scheld, H. W.

    1987-01-01

    An attempt is made to summarize work in plant cell technologies in space. The evolution of concepts and the general principles of plant tissue culture are discussed. The potential for production of high value secondary products by plant cells and differentiated tissue in automated, precisely controlled bioreactors is discussed. The general course of the development of the literature on plant tissue culture is highlighted.

  19. Degradation of TNT by plant cell cultures

    Czech Academy of Sciences Publication Activity Database

    Podlipná, Radka; Nepovím, Aleš; Zeman, S.; Vágner, Martin; Vaněk, Tomáš

    Smolenice, 2003, s. 78-79. [Xenobiochemické sympózium /22./. Smolenice (SK), 09.06.2003-11.06.2003] R&D Projects: GA ČR GP206/02/P065; GA MŠk OC 837.10 Institutional research plan: CEZ:AV0Z5038910; CEZ:AV0Z4055905 Keywords : degradation * plant cell cultures Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides

  20. How do plant cell walls extend?

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

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

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

    OpenAIRE

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

    2009-01-01

    Pectin or pectic substances are collective names for a group of closely associated polysaccharides present in plant cell walls where they contribute to complex physiological processes like cell growth and cell differentiation and so determine the integrity and rigidity of plant tissue. They also play an important role in the defence mechanisms against plant pathogens and wounding. As constituents of plant cell walls and due to their anionic nature, pectic polysaccharides are considered to be ...

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

    OpenAIRE

    Li, Zhuo

    2009-01-01

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

  3. Myocardial Cell Pattern on Piezoelectric Nanofiber Mats for Energy Harvesting

    International Nuclear Information System (INIS)

    The paper presents in vitro contractile myocardial cell pattern on piezoelectric nanofiber mats with applications in energy harvesting. The cell-based energy harvester consists of myocardial cell sheet and a PDMS substrate with a PVDF nanofiber mat on. Experimentally, cultured on specifically distributed nanofiber mats, neonatal rat ventricular cardiomyocytes are characterized with the related morphology and contraction. Previously, we have come up with the concept of energy harvesting from heart beating using piezoelectric material. A bio-hybrid energy harvester combined living cardiomyocytes, PDMS polymer substrate and piezoelectric PVDF film with the electrical output of peak current 87.5nA and peak voltage 92.3mV. However, the thickness of the cardiomyocyte cultured on a two-dimensional substrate is much less than that of the piezoelectric film. The Micro Contact Printing (μCP) method used in cell pattern on the PDMS thin film has tough requirement for the film surface. As such, in this paper we fabricated nanofiber-constructed PDMS thin film to realize cell pattern due to PVDF nanofibers with better piezoelectricity and microstructures of nanofiber mats guiding cell distribution. Living cardiomyocytes patterned on those distributed piezoelectric nanofibers with the result of the same distribution as the nanofiber pattern

  4. Advances in methods for measuring patterns of endemic plant diversity

    Directory of Open Access Journals (Sweden)

    Jihong Huang

    2013-01-01

    Full Text Available Endemism, the restriction of a taxon’s distribution to a specified geographical area, is central to the study of biogeography. Understanding endemism not only concerns a number of evolutionary and biogeographical issues, but also plays an important role in maintaining biodiversity and in the selection of priority areas for conservation. In recent years, various measures and analytical methods have been used to investigate patterns of endemism for various taxa from different regions. The emergence of these new measurements has benefited from the construction of phylogenetic trees and the implementation of data from spatial statistics. Some of these measures, such as phylogenetic diversity, phylogenetic endemism, and biogeographically weighted evolutionary distinctiveness deserve much more attention. Here, we review progress in the methodology used to measure the distribution patterns of endemism. These metrics have generally developed from a single time or space perspective to space-time united patterns. Specifically, the metrics include species richness, phylogenetic diversity and evolutionary distinctiveness, plus all there in combination as well as the weight of species range size. Moreover, we propose that studies on the distribution patterns of Chinese endemic taxa should pay attention to species diversity, phylogenetic diversity, species β-diversity, and phylogenetic β-diversity. In particular, model simulation analysis should be emphasized and implemented during investigations. These studies will provide fundamental knowledge for comprehensive recognition of scale-induced differences and for the detection of mechanisms underlying the distribution patterns of endemic taxa, and therefore provide theoretical support for biodiversity conservation.

  5. Cell polarity and patterning by PIN trafficking through early endosomal compartments in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Hirokazu Tanaka

    2013-05-01

    Full Text Available PIN-FORMED (PIN proteins localize asymmetrically at the plasma membrane and mediate intercellular polar transport of the plant hormone auxin that is crucial for a multitude of developmental processes in plants. PIN localization is under extensive control by environmental or developmental cues, but mechanisms regulating PIN localization are not fully understood. Here we show that early endosomal components ARF GEF BEN1 and newly identified Sec1/Munc18 family protein BEN2 are involved in distinct steps of early endosomal trafficking. BEN1 and BEN2 are collectively required for polar PIN localization, for their dynamic repolarization, and consequently for auxin activity gradient formation and auxin-related developmental processes including embryonic patterning, organogenesis, and vasculature venation patterning. These results show that early endosomal trafficking is crucial for cell polarity and auxin-dependent regulation of plant architecture.

  6. An unusual scintigraphic pattern in sickle cell patients

    International Nuclear Information System (INIS)

    We reviewed the nuclear medicine files of all patients enrolled in the sickle cell disease clinic who had had scans performed within the previous 5 years. We specifically looked for patterns of tracer uptake in these scans that would correlate with the severe anemia and consequent bone marrow hyperactivity of sickle cell patients. Thirty-three patients were included (21 men and 12 women) with a mean age of 26.8 years (range 17-48 years). The appearance of each of these patients' most recent scans was examined in the areas of the distal femurs, the proximal tibias and the distal tibias; a distinct triangular shaped pattern of increased activity was identified in these areas in a majority of patients. Thirty-three patients without sickle cell disease served as age-matched controls. This pattern was seen in 65.1% (95 out of 146 images) of the sickle cell patients' delayed images and 80.4% (82 out of 102 images) of their blood pool images. In contrast, the control patients demonstrated the triangular pattern in none of their blood pool studies (0%) and only 10.9% of their delayed bone images (P<0.001). The mean age of sickle cell patients with this pattern is 25.6 years which was significantly lower than that of those without this pattern (mean=37.5 years, P<0.05). Given the high prevalence of this unique scintigraphic pattern in a group of patients with known accelerated bone marrow function, these findings may be scintigraphic evidence of bone marrow expansion. The patient's age appears to be an important factor in visualization of this pattern. (orig.)

  7. Systematic analysis of stability patterns in plant primary metabolism.

    Directory of Open Access Journals (Sweden)

    Dorothee Girbig

    Full Text Available Metabolic networks are characterized by complex interactions and regulatory mechanisms between many individual components. These interactions determine whether a steady state is stable to perturbations. Structural kinetic modeling (SKM is a framework to analyze the stability of metabolic steady states that allows the study of the system Jacobian without requiring detailed knowledge about individual rate equations. Stability criteria can be derived by generating a large number of structural kinetic models (SK-models with randomly sampled parameter sets and evaluating the resulting Jacobian matrices. Until now, SKM experiments applied univariate tests to detect the network components with the largest influence on stability. In this work, we present an extended SKM approach relying on supervised machine learning to detect patterns of enzyme-metabolite interactions that act together in an orchestrated manner to ensure stability. We demonstrate its application on a detailed SK-model of the Calvin-Benson cycle and connected pathways. The identified stability patterns are highly complex reflecting that changes in dynamic properties depend on concerted interactions between several network components. In total, we find more patterns that reliably ensure stability than patterns ensuring instability. This shows that the design of this system is strongly targeted towards maintaining stability. We also investigate the effect of allosteric regulators revealing that the tendency to stability is significantly increased by including experimentally determined regulatory mechanisms that have not yet been integrated into existing kinetic models.

  8. Dynamic instability of genomic methylation patterns in pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Ooi Steen KT

    2010-09-01

    Full Text Available Abstract Background Genomic methylation patterns are established during gametogenesis, and perpetuated in somatic cells by faithful maintenance methylation. There have been previous indications that genomic methylation patterns may be less stable in embryonic stem (ES cells than in differentiated somatic cells, but it is not known whether different mechanisms of de novo and maintenance methylation operate in pluripotent stem cells compared with differentiating somatic cells. Results In this paper, we show that ablation of the DNA methyltransferase regulator DNMT3L (DNA methyltransferase 3-like in mouse ES cells renders them essentially incapable of de novo methylation of newly integrated retroviral DNA. We also show that ES cells lacking DNMT3L lose DNA methylation over time in culture, suggesting that DNA methylation in ES cells is the result of dynamic loss and gain of DNA methylation. We found that wild-type female ES cells lose DNA methylation at a much faster rate than do male ES cells; this defect could not be attributed to sex-specific differences in expression of DNMT3L or of any DNA methyltransferase. We also found that human ES and induced pluripotent stem cell lines showed marked but variable loss of methylation that could not be attributed to sex chromosome constitution or time in culture. Conclusions These data indicate that DNA methylation in pluripotent stem cells is much more dynamic and error-prone than is maintenance methylation in differentiated cells. DNA methylation requires DNMT3L in stem cells, but DNMT3L is not expressed in differentiating somatic cells. Error-prone maintenance methylation will introduce unpredictable phenotypic variation into clonal populations of pluripotent stem cells, and this variation is likely to be much more pronounced in cultured female cells. This epigenetic variability has obvious negative implications for the clinical applications of stem cells.

  9. Functions of Xyloglucan in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Takahisa Hayashi; Rumi Kaida

    2011-01-01

    While an increase in the number of xyloglucan tethers between the cellulose microfibrils in plant cell walls increases the walls' rigidity, the degradation of these tethers causes the walls to loosen. Degradation can occur either through the integration of xyloglucan oligosaccharides due to the action of xyloglucan endotransglucosylase or through direct hydrolysis due to the action of xyloglucanase. This is why the addition of xyloglucan and its fragment oligosac-charides causes plant tissue tension to increase and decrease so dramatically. Experiments involving the overexpression of xyloglucanase and cellulase have revealed the roles of xyloglucans in the walls. The degradation of wall xyloglucan in poplar by the transgenic expression of xyloglucanase, for example, not only accelerated stem elongation in the primary wall, but also blocked upright-stem gravitropism in the secondary wall. Overexpression of cellulase also reduced xyloglucan content in the walls as cellulose microfibrils were trimmed at their amorphous region, resulting in increased cell volume in Arabidopsis leaves and in sengon with disturbed leaf movements. The hemicellulose xyloglucan, in its function as a tether, plays a key role in the loosening and tightening of cellulose microfibrils: it enables the cell to change its shape in growth and differentiation zones and to retain its final shape after cell maturation.

  10. Distribution patterns of rare earth elements in various plant species

    International Nuclear Information System (INIS)

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs

  11. Distribution patterns of rare earth elements in various plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wyttenbach, A.; Tobler, L.; Furrer, V. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs.

  12. Resource competition in plant invasions: emerging patterns and research needs

    Directory of Open Access Journals (Sweden)

    Margherita eGioria

    2014-09-01

    Full Text Available Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relatively to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, while invasive congeners are not necessarily competitively superior over native congeners, nor alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy. We then identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examinations of resource competition dynamics and of the impact of global environmental changes on competitive interactions between invasive and native

  13. 2003 Plant Cell Walls Gordon Conference

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Cosgrove

    2004-09-21

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

  14. A Biodiversity Informatics Approach to Ethnobotany: Meta-analysis of Plant Use Patterns in Ecuador

    DEFF Research Database (Denmark)

    de la Torre, Lucia; Cerón, Carlos E.; Balslev, Henrik;

    2012-01-01

    We explored the relative importance of ecosystem diversity, socioeconomic, environmental, and geographical factors in determining the pattern and diversity of people’s plant use in Ecuador, based on existing ethnobotanic investigations and a large database of georeferenced plant collections. For...

  15. Primary observations of the existence of Fas-like cytoplasmic death factor in plant cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The main activity of Fas is to trigger cytoplasm death program in animal cells. In G2 pea, vacuole plays a pivotal role in inducing cell death in the cytoplasm of longday (LD) grown apical meristem cells. Expression patterns of the Fas in G2 pea cells revealed that the Fas is mainly localized in the vacuole of cells undergoing programmed cell death (PCD). The Fas expression is corresponding to the initiation of menadione-induced PCD in tobacco protoplasts.The results suggest the existence of the Fas-like mediated cytoplasmic death pathway in plant cells.``

  16. Roles of membrane trafficking in plant cell wall dynamics

    OpenAIRE

    Ebine, Kazuo; Ueda, Takashi

    2015-01-01

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

  17. Colonization patterns of an mCherry-tagged Pectobacterium carotovorum subsp. brasiliense strain in potato plants.

    Science.gov (United States)

    Kubheka, Gugulethu C; Coutinho, Teresa A; Moleleki, Ntsane; Moleleki, Lucy N

    2013-12-01

    Pectobacterium carotovorum subsp. brasiliense is a newly identified member of the potato soft rot enterobacteriaceae. The pathogenesis of this pathogen is still poorly understood. In this study, an mCherry-P. carotovorum subsp. brasiliense-tagged strain was generated to study P. carotovorum subsp. brasiliense-potato plant interactions. Prior to use, the tagged strain was evaluated for in vitro growth, plasmid stability, and virulence on potato tubers and shown to be similar to the wild type. Four potato cultivars were evaluated for stem-based resistance against P. carotovorum subsp. brasiliense. Confocal laser-scanning microscopy and in vitro viable cell counts showed that P. carotovorum subsp. brasiliense is able to penetrate roots of a susceptible potato cultivar as early as 12 h postinoculation and migrate upward into aerial stem parts. Due to the phenotypic differences observed between tolerant and susceptible cultivars, a comparison of P. carotovorum subsp. brasiliense colonization patterns in these cultivars was undertaken. In the susceptible cultivar, P. carotovorum subsp. brasiliense cells colonized the xylem tissue, forming "biofilm-like" aggregates that led to occlusion of some of the vessels. In contrast, in the tolerant cultivar, P. carotovorum subsp. brasiliense appeared as free-swimming planktonic cells with no specific tissue localization. This suggests that there are resistance mechanisms in the tolerant cultivar that limit aggregation of P. carotovorum subsp. brasiliense in planta and, hence, the lack of symptom development in this cultivar. PMID:23758294

  18. Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

    Directory of Open Access Journals (Sweden)

    Wan Nurlina Wan Yahya

    2014-07-01

    Full Text Available Liver transplantation is the most common treatment for patients with end-stage liver failure. However, liver transplantation is greatly limited by a shortage of donors. Liver tissue engineering may offer an alternative by providing an implantable engineered liver. Currently, diverse types of engineering approaches for in vitro liver cell culture are available, including scaffold-based methods, microfluidic platforms, and micropatterning techniques. Active cell patterning via dielectrophoretic (DEP force showed some advantages over other methods, including high speed, ease of handling, high precision and being label-free. This article summarizes liver function and regenerative mechanisms for better understanding in developing engineered liver. We then review recent advances in liver tissue engineering techniques and focus on DEP-based cell patterning, including microelectrode design and patterning configuration.

  19. Geographical patterns in the beta diversity of China's woody plants

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao;

    2012-01-01

    with their environmental niches due to dispersal limitation induced by China’s topography and/or their low dispersal ability. The projected rapid climatic changes will likely endanger such species. Species dispersal processes should be taken into account in future conservation strategies in China........g. environmental niche versus dispersal limitation of species) remains elusive, and the influence of species range size has been poorly tested. Here, using distribution maps of 11 405 woody species in China (ca 9.6 ¿ 106 km2), we investigated 1) the geographical and directional patterns of beta diversity for all...... availability, climatic seasonality, habitat heterogeneity and human activities were used to evaluate the effects of environmental processes, while spatial distance was used to assess the influence of spatial processes. The results indicated significant directional patterns of beta diversity: the similarity...

  20. Environmental Drivers of Patterns of Plant Diversity Along a Wide Environmental Gradient in Korean Temperate Forests

    Directory of Open Access Journals (Sweden)

    Chang-Bae Lee

    2016-01-01

    Full Text Available Understanding patterns of biodiversity and their drivers along environmental gradients is one of the central topics in ecology. However, whether diversity patterns along environmental gradients differ among diversity components as well as life forms and what kind of variables control or interact to shape the diversity patterns are poorly known. This study scrutinized the distribution patterns of three plant groups with four diversity indices and evaluated the effects of regional area, topography, topographic heterogeneity, climate, primary productivity, vegetation structure diversity and vegetation type diversity along an extensive elevational gradient on the Baekdudaegan Mountains in South Korea. Different elevational patterns, including hump-shaped, reversed hump-shaped, increasing, multimodal and no relationship, were observed among both the diversity indices and the plant groups. Regional area, habitat heterogeneity and climate were included to explain most of the elevational diversity patterns. In particular, habitat heterogeneity was the most important variable for explaining the patterns of diversity. The results suggest that patterns of elevational diversity may differ not only among plant groups but also among diversity indices and that such patterns are primarily caused by habitat heterogeneity in the Baekdudaegan Mountains because more heterogeneous and diverse habitats can support more coexisting species.

  1. Energy pattern analysis of a wastewater treatment plant

    Science.gov (United States)

    Singh, Pratima; Carliell-Marquet, Cynthia; Kansal, Arun

    2012-09-01

    Various forms of energy are used during a wastewater treatment process like electrical, manual, fuel, chemical etc. Most of the earlier studies have focused only on electrical energy intensity of large-scale centralized wastewater treatment plants (WWTPs). This paper presents a methodological framework for analysing manual, mechanical, chemical and electrical energy consumption in a small-scaled WWTP. The methodology has been demonstrated on a small-scale WWTP in an institutional area. Total energy intensity of the plant is 1.046 kWh/m3 of wastewater treated. Electrical energy is only about half of the total energy consumption. Manual energy also has a significant share, which means that the small-scale treatment plants offer significant employment opportunities in newly industrializing countries and replaces fossil fuel-based energy with renewable. There is a lack of sufficient data in the literature for comparison, and few studies have reported values that vary significantly due to the difference in scale, scope of the study and the choice of the treatment technologies. Replication of similar studies and generation of data in this area will offer directions for decision on choice of the scale of wastewater treatment process from the considerations of energy and climate change mitigation strategies.

  2. Patterns and Environmental Determinants of Medicinal Plant : Vascular Plant Ratios in Xinjiang, Northwest China

    Science.gov (United States)

    Zhang, Bengang; Xiao, Peigen; Qi, Yaodong; Zhang, Zhao; Liu, Haitao; Li, Xiaojin; Wang, Guoping; Terwei, André

    2016-01-01

    With both a full collection of native vascular plant distributions and a full checklist of source plants of the Chinese Materia Medica (CMM), the Uygur Medicine (UM), and the Kazak Medicine (KM) for the Xinjiang region, we defined medicinal plant: vascular plant ratios (simplified as medicinal plant ratios hereafter) as the value of medicinal plant richness divided by vascular plant richness. We aimed to find whether the ratios are constant or change in different environments, which environmental variables determine medicinal plant ratios, and whether the ratios are more influenced by human or by natural environments. Finally, suggestions for medicinal plant conservation were addressed. We found that (1) medicinal plant ratios were not constant, and they were high in the Tarim Basin which was largely covered by desert, while they were relatively low in mountainous areas, especially in the Tianshan Mountains where the general species richness was high; (2) medicinal plant ratios were not significantly influenced by human activities, indicated by human population density distributions, but they were highly correlated with plant species richness and climate, i.e. ratios decreased with plant species richness and MAP, and were related quadratically with MAT; (3) CMM ratio and UM ratio were more influenced by plant richness than by climate, while KM ratio was more influenced by climate. We concluded that the percentages of plants used as medicines were not influenced by distances from human settlements, but were determined by species richness or climate. We suggest that (1), in general, the medicinal plant ratio could be a complementary indicator for medicinal plant conservation planning and (2), for the region of Xinjiang, not only high diversity areas, but also some extreme environments should be considered as compensation for a better protection of medicinal plants. PMID:27391239

  3. Patterns and Environmental Determinants of Medicinal Plant : Vascular Plant Ratios in Xinjiang, Northwest China.

    Directory of Open Access Journals (Sweden)

    Liping Li

    Full Text Available With both a full collection of native vascular plant distributions and a full checklist of source plants of the Chinese Materia Medica (CMM, the Uygur Medicine (UM, and the Kazak Medicine (KM for the Xinjiang region, we defined medicinal plant: vascular plant ratios (simplified as medicinal plant ratios hereafter as the value of medicinal plant richness divided by vascular plant richness. We aimed to find whether the ratios are constant or change in different environments, which environmental variables determine medicinal plant ratios, and whether the ratios are more influenced by human or by natural environments. Finally, suggestions for medicinal plant conservation were addressed. We found that (1 medicinal plant ratios were not constant, and they were high in the Tarim Basin which was largely covered by desert, while they were relatively low in mountainous areas, especially in the Tianshan Mountains where the general species richness was high; (2 medicinal plant ratios were not significantly influenced by human activities, indicated by human population density distributions, but they were highly correlated with plant species richness and climate, i.e. ratios decreased with plant species richness and MAP, and were related quadratically with MAT; (3 CMM ratio and UM ratio were more influenced by plant richness than by climate, while KM ratio was more influenced by climate. We concluded that the percentages of plants used as medicines were not influenced by distances from human settlements, but were determined by species richness or climate. We suggest that (1, in general, the medicinal plant ratio could be a complementary indicator for medicinal plant conservation planning and (2, for the region of Xinjiang, not only high diversity areas, but also some extreme environments should be considered as compensation for a better protection of medicinal plants.

  4. Plant and animal stem cells: similar yet different

    NARCIS (Netherlands)

    Heidstra, R.; Sabatini, S.

    2014-01-01

    The astonishingly long lives of plants and their regeneration capacity depend on the activity of plant stem cells. As in animals, stem cells reside in stem cell niches, which produce signals that regulate the balance between self-renewal and the generation of daughter cells that differentiate into n

  5. Molecular regulation of plant cell wall extensibility

    Science.gov (United States)

    Cosgrove, D. J.

    1998-01-01

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

  6. Modeling cell-death patterning during biofilm formation

    International Nuclear Information System (INIS)

    Self-organization by bacterial cells often leads to the formation of a highly complex spatially-structured biofilm. In such a bacterial biofilm, cells adhere to each other and are embedded in a self-produced extracellular matrix (ECM). Bacillus substilis bacteria utilize localized cell-death patterns which focuses mechanical forces to form wrinkled sheet-like structures in three dimensions. A most intriguing feature underlying this biofilm formation is that vertical buckling and ridge location is biased to occur in region of high cell-death. Here we present a spatially extended model to investigate the role of the bacterial secreted ECM during the biofilm formation and the self-organization of cell-death. Using this reaction-diffusion model we show that the interaction between the cell's motion and the ECM concentration gives rise to a self-trapping instability, leading to variety of cell-death patterns. The resultant spot patterns generated by our model are shown to be in semi-quantitative agreement with recent experimental observation. (paper)

  7. Patterned cell arrays and patterned co-cultures on polydopamine-modified poly(vinyl alcohol) hydrogels

    International Nuclear Information System (INIS)

    Live cell arrays are an emerging tool that expand traditional 2D in vitro cell culture, increasing experimental precision and throughput. A patterned cell system was developed by combining the cell-repellent properties of polyvinyl alcohol hydrogels with the cell adhesive properties of self-assembled films of dopamine (polydopamine). It was shown that polydopamine could be patterned onto spin-cast polyvinyl alcohol hydrogels by microcontact printing, which in turn effectively patterned the growth of several cell types (HeLa, human embryonic kidney, human umbilical vein endothelial cells (HUVEC) and prostate cancer). The cells could be patterned in geometries down to single-cell confinement, and it was demonstrated that cell patterns could be maintained for at least 3 weeks. Furthermore, polydopamine could be used to modify poly(vinyl alcohol) in situ using a cell-compatible deposition buffer (1 mg mL−1 dopamine in 25 mM tris with a physiological salt balance). The treatment switched the PVA hydrogel from cell repellent to cell adhesive. Finally, by combining microcontact printing and in situ deposition of polydopamine, patterned co-cultures of the same cell type (HeLa/HeLa) and dissimilar cell types (HeLa/HUVEC) were realized through simple chemistry and could be studied over time. The combination of polyvinyl alcohol and polydopamine was shown to be an attractive route to versatile, patterned cell culture experiments with minimal infrastructure requirements and low complexity. (paper)

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

    OpenAIRE

    Ptashnyk, Mariya; Seguin, Brian

    2015-01-01

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

  9. Dynamic simulation of a direct carbonate fuel cell power plant

    Energy Technology Data Exchange (ETDEWEB)

    Ernest, J.B. [Fluor Daniel, Inc., Irvine, CA (United States); Ghezel-Ayagh, H.; Kush, A.K. [Fuel Cell Engineering, Danbury, CT (United States)

    1996-12-31

    Fuel Cell Engineering Corporation (FCE) is commercializing a 2.85 MW Direct carbonate Fuel Cell (DFC) power plant. The commercialization sequence has already progressed through construction and operation of the first commercial-scale DFC power plant on a U.S. electric utility, the 2 MW Santa Clara Demonstration Project (SCDP), and the completion of the early phases of a Commercial Plant design. A 400 kW fuel cell stack Test Facility is being built at Energy Research Corporation (ERC), FCE`s parent company, which will be capable of testing commercial-sized fuel cell stacks in an integrated plant configuration. Fluor Daniel, Inc. provided engineering, procurement, and construction services for SCDP and has jointly developed the Commercial Plant design with FCE, focusing on the balance-of-plant (BOP) equipment outside of the fuel cell modules. This paper provides a brief orientation to the dynamic simulation of a fuel cell power plant and the benefits offered.

  10. Divergent T-Cell Cytokine Patterns in Inflammatory Arthritis

    Science.gov (United States)

    Simon, A. K.; Seipelt, E.; Sieper, J.

    1994-08-01

    A major immunoregulatory mechanism in inflammatory infections and allergic diseases is the control of the balance of cytokines secreted by Th1/Th2 subsets of T helper (Th) cells. This might also be true in autoimmune diseases; a Th2 pattern that prevents an effective immune response in infections with intracellular bacteria may favor immunosuppression in autoimmune diseases. The pattern of cytokine expression was compared in the synovial tissue from patients with a typical autoimmune disease, rheumatoid arthritis, and with a disorder with similar synovial pathology but driven by persisting exogenous antigen, reactive arthritis. We screened 12 rheumatoid and 9 reactive arthritis synovial tissues by PCR and in situ hybridization for their expression of T-cell cytokines. The cytokine pattern differs significantly between the two diseases; rheumatoid arthritis samples express a Th1-like pattern whereas in reactive arthritis interferon γ expression is accompanied by that of interleukin 4. Studying the expression of cytokines by in situ hybridization confirmed the results found by PCR; they also show an extremely low frequency of cytokine-transcribing cells. In a double-staining experiment, it was demonstrated that interleukin 4 is made by CD4 cells. These experiments favor the possibility of therapeutic intervention in inflammatory rheumatic diseases by means of inhibitory cytokines.

  11. Glow in the Dark: Fluorescent Proteins as Cell and Tissue-Specific Markers in Plants

    Institute of Scientific and Technical Information of China (English)

    Wenzislava Ckurshumova; Adriana E. Caragea; Rochelle S. Goldstein; Thomas Berleth

    2011-01-01

    Since the hallmark discovery of Aequorea victoria's Green Fluorescent Protein (GFP) and its adaptation for efficient use in plants,fluorescent protein tags marking expression profiles or genuine proteins of interest have been used to recognize plant tissues and cell types,to monitor dynamic cell fate selection processes,and to obtain cell type-specific transcriptomes.Fluorescent tagging enabled visualization in living tissues and the precise recordings of dynamic expression pattern changes.The resulting accurate recording of cell fate acquisition kinetics in space and time has strongly stimulated mathematical modeling of self-organizing feedback mechanisms.In developmental studies,the use of fluorescent proteins has become critical,where morphological markers of tissues,cell types,or differentiation stages are either not known or not easily recognizable.In this review,we focus on the use of fluorescent markers to identify and illuminate otherwise invisible cell states in plant development.

  12. Plant Cell Wall Matrix Polysaccharide Biosynthesis

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  13. Plant Biomarker Pattern, Screening Programme for Phytochemical Differences in Plants Exposed to Stress

    OpenAIRE

    Christensen, Trine F.; Diedrichsen, Brigitte; Adsersen, Anne; Andersen, Jan Buch; Ravn, Helle Weber

    2002-01-01

    A screening programme is developed to investigate phytochemical differences in plants xposed to stress compared with non-exposed plants. The screening programme, in its resent form or in a more simplified form, can be utilized in several different areas as a preliminary broad screening. The screening programme covers the most general groups of compounds found in plants. The following groups of phytochemical compounds are included in the programme: Unspecific compounds, organic acids, lipid...

  14. Pattern matching based active optical sorting of colloids/cells

    International Nuclear Information System (INIS)

    We report active optical sorting of colloids/cells by employing a cross correlation based pattern matching technique for selection of the desired objects and thereafter sorting using dynamically controllable holographic optical traps. The problem of possible collision between the different sets of objects during sorting was avoided by raising one set of particles to a different plane. We also present the results obtained on using this approach for some representative applications such as sorting of silica particles of two different sizes, of closely packed colloids and of white blood cells and red blood cells from a mixture of the two. (paper)

  15. Regional differences in lectin binding patterns of vestibular hair cells

    Science.gov (United States)

    Baird, Richard A.; Schuff, N. R.; Bancroft, J.

    1994-01-01

    Surface glycoconjugates of hair cells and supporting cells in the vestibular endorgans of the bullfrog were identified using biotinylated lectins with different carbohydrate specificities. Lectin binding in hair cells was consistent with the presence of glucose and mannose (CON A), galactose (RCA-I), N-acetylgalactosamine (VVA), but not fucose (UEA-I) residues. Hair cells in the bullfrog sacculus, unlike those in the utriculus and semicircular canals, did not stain for N-acetylglucosamine (WGA) or N-acetylgalactosamine (VVA). By contrast, WGA and, to a lesser extent, VVA, differentially stained utricular and semicircular canal hair cells, labeling hair cells located in peripheral, but not central, regions. In mammals, WGA uniformly labeled Type 1 hair cells while labeling, as in the bullfrog, Type 2 hair cells only in peripheral regions. These regional variations were retained after enzymatic digestion. We conclude that vestibular hair cells differ in their surface glycoconjugates and that differences in lectin binding patterns can be used to identify hair cell types and to infer the epithelial origin of isolated vestibular hair cells.

  16. Hierarchical Patterning of Cells with a Microeraser and Electrospun Nanofibers.

    Science.gov (United States)

    Li, Yan; Jiang, Xueqin; Zhong, Huixiang; Dai, Wen; Zhou, Jianhua; Wu, Hongkai

    2016-03-01

    For tissue engineering applications, it is important to develop fabrication strategies for building models with controlled cell distributions in defined structures. Here, a simple, flexible approach (named the μ-eraser strategy) is developed to construct multicell micropatterns. This approach involves pressing a poly(dimethylsiloxane) stamp to erase cells growing on substrates, and seeding other types of cells. The pressing/seeding process can be conducted in any designed pattern at desired time point. In a proof of concept, multicell micropatterns of human lung adenocarcinoma epithelial A549 cells, murine fibroblast (FB) cells and murine osteoblast (OB) cells are achieved on Petri dishes and electrospun sheets. Besides forming multicell micropatterns, the cell orientation can be regulated by microstripes and alignment of nanofibers. On Petri dishes and random fiber sheets, FB and OB cells align along microstripes, while A549 cells do not. However, when growing on aligned fiber sheets, no matter whether solo-cultured or co-cultured, all cells in micropatterns orient along the fibers. Based on this technique, a platform is built up to investigate rates of cell migration and interinvasion under solo-culture and co-culture systems. It is believed that this μ-eraser strategy has promise for biological, pharmaceutical, and biomedical applications. PMID:26682534

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  18. Agro-economic performance of mungbean intercropped in sesame under different planting patterns

    International Nuclear Information System (INIS)

    The performance of mungbean intercropped in sesame under different geometric arrangements was determined o sandy-clay loam soil at the university of Agriculture, Faisalabad for two consecutive years (2001-02). The planting patterns consisted of 40 cm spaced single rows, 60 cm spaced 3-row strips and 100 cm spaced 4-row strip while mungbean was intercropped in all the three planting patterns and also grown as a sole crop. The result evinced that planting sesame in 100 cm spaced 4-row strips explored the intercropping in sesame. It not only permitted convenient intercropping but also facilitated the harvesting and handling of intercrop without doing any damage to the base crop. Intercropping sesame with mungbean in the pattern of 100 cm spaced 4-row strips appeared to be more convenient, productive and profitable than the monocropped sesame. (author)

  19. Pattern formation in solutal convection: vermiculated rolls and isolated cells

    Science.gov (United States)

    Cartwright, Julyan H. E.; Piro, Oreste; Villacampa, Ana I.

    2002-11-01

    Observations of the peculiar behaviour of a drink of liqueur topped with cream led us to perform experiments showing that the instability is a convection phenomenon that arises through destabilizing surface-tension forces. The convection is solutal: driven by gradients of concentration of a solute, rather than by heat gradients as in the more commonly studied thermal convection. The convective patterns, vermiculated rolls and isolated cells, are quite unlike the usual planforms. They are associated with an elastic surface film, and the Marangoni number is high, characteristic of solutal convection. We have conducted further experiments that reproduce these patterns in simpler working fluids.

  20. [Plant community patterns of piosphere in the Mu Us Sandland of China].

    Science.gov (United States)

    Yu, Hong; Wu, Bo; He, Ji; Jia, Zi-yi; Yan, Feng

    2015-02-01

    Piosphere is ubiquitous in drylands. Plant communities of ten paddocks were investigated along transects starting from watering points in the Mu Us Sandland. By using the method of regression and indirect gradient ordination, the richness of plant community and plant functional types were analyzed. The results showed that with the increase of distance from the watering points, the traits of the plant communities varied significantly. The coverage of the community, shrubs and grasses gradually increased and the coverage of forbs decreased with the distance increasing from the watering points. The patterns of the community richness and coverage suggested the grazing gradient surrounding the watering points. The piosphere is a breakthrough point to reveal the degradation pattern of rangeland and its driving forces in northern China. PMID:26094451

  1. Plant guard cell anion channel SLAC1 regulates stomatal closure

    OpenAIRE

    Vahisalu, Triin

    2010-01-01

    Plants are rooted to their growth place; therefore it is important that they react adequately to changes in environmental conditions. Stomatal pores, which are formed of a pair of guard cells in leaf epidermis, regulate plant gas-exchange. Importantly, guard cells protect the plant from desiccation in drought conditions by reducing the aperture of the stomatal pore. They serve also as the first barrier against the major air pollutant ozone, but the behaviour of guard cells during ozone expo...

  2. Relative role of contemporary environment versus history in shaping diversity patterns of China's woody plants

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao;

    2012-01-01

    What determines large-scale patterns of species diversity is a central and controversial topic in biogeography and ecology. In this study, we compared the effects of contemporary environment and historical contingencies on species richness patterns of woody plants in China, using fine-resolution ......-plant species richness across China, while historical contingencies generate regional deviations from this trend. Our findings imply that both species diversity and regional evolutionary and ecological histories should be taken into account for future nature conservation.......What determines large-scale patterns of species diversity is a central and controversial topic in biogeography and ecology. In this study, we compared the effects of contemporary environment and historical contingencies on species richness patterns of woody plants in China, using fine...... regions combined. This suggests different richness-environment relationships among regions. These results indicate important historical signals in the species richness patterns of woody plants across China. The signals are especially pronounced in the eastern Himalayas, the Mongolian Plateau, and the...

  3. Life histories of hosts and pathogens predict patterns in tropical fungal plant diseases.

    Science.gov (United States)

    García-Guzmán, Graciela; Heil, Martin

    2014-03-01

    Plant pathogens affect the fitness of their hosts and maintain biodiversity. However, we lack theories to predict the type and intensity of infections in wild plants. Here we demonstrate using fungal pathogens of tropical plants that an examination of the life histories of hosts and pathogens can reveal general patterns in their interactions. Fungal infections were more commonly reported for light-demanding than for shade-tolerant species and for evergreen rather than for deciduous hosts. Both patterns are consistent with classical defence theory, which predicts lower resistance in fast-growing species and suggests that the deciduous habit can reduce enemy populations. In our literature survey, necrotrophs were found mainly to infect shade-tolerant woody species whereas biotrophs dominated in light-demanding herbaceous hosts. Far-red signalling and its inhibitory effects on jasmonic acid signalling are likely to explain this phenomenon. Multiple changes between the necrotrophic and the symptomless endophytic lifestyle at the ecological and evolutionary scale indicate that endophytes should be considered when trying to understand large-scale patterns in the fungal infections of plants. Combining knowledge about the molecular mechanisms of pathogen resistance with classical defence theory enables the formulation of testable predictions concerning general patterns in the infections of wild plants by fungal pathogens. PMID:24171899

  4. Patterns of phenotypic correlations among morphological traits across plants and animals

    OpenAIRE

    Conner, Jeffrey K; Cooper, Idelle A.; La Rosa, Raffica J.; Pérez, Samuel G.; Royer, Anne M.

    2014-01-01

    Despite the long-standing interest of biologists in patterns of correlation and phenotypic integration, little attention has been paid to patterns of correlation across a broad phylogenetic spectrum. We report analyses of mean phenotypic correlations among a variety of linear measurements from a wide diversity of plants and animals, addressing questions about function, development, integration and modularity. These analyses suggest that vertebrates, hemimetabolous insects and vegetative trait...

  5. Spatially patterned matrix elasticity directs stem cell fate

    Science.gov (United States)

    Yang, Chun; DelRio, Frank W.; Ma, Hao; Killaars, Anouk R.; Basta, Lena P.; Kyburz, Kyle A.; Anseth, Kristi S.

    2016-01-01

    There is a growing appreciation for the functional role of matrix mechanics in regulating stem cell self-renewal and differentiation processes. However, it is largely unknown how subcellular, spatial mechanical variations in the local extracellular environment mediate intracellular signal transduction and direct cell fate. Here, the effect of spatial distribution, magnitude, and organization of subcellular matrix mechanical properties on human mesenchymal stem cell (hMSCs) function was investigated. Exploiting a photodegradation reaction, a hydrogel cell culture substrate was fabricated with regions of spatially varied and distinct mechanical properties, which were subsequently mapped and quantified by atomic force microscopy (AFM). The variations in the underlying matrix mechanics were found to regulate cellular adhesion and transcriptional events. Highly spread, elongated morphologies and higher Yes-associated protein (YAP) activation were observed in hMSCs seeded on hydrogels with higher concentrations of stiff regions in a dose-dependent manner. However, when the spatial organization of the mechanically stiff regions was altered from a regular to randomized pattern, lower levels of YAP activation with smaller and more rounded cell morphologies were induced in hMSCs. We infer from these results that irregular, disorganized variations in matrix mechanics, compared with regular patterns, appear to disrupt actin organization, and lead to different cell fates; this was verified by observations of lower alkaline phosphatase (ALP) activity and higher expression of CD105, a stem cell marker, in hMSCs in random versus regular patterns of mechanical properties. Collectively, this material platform has allowed innovative experiments to elucidate a novel spatial mechanical dosing mechanism that correlates to both the magnitude and organization of spatial stiffness. PMID:27436901

  6. Directing cell migration and organization via nanocrater-patterned cell-repellent interfaces

    Science.gov (United States)

    Jeon, Hojeong; Koo, Sangmo; Reese, Willie Mae; Loskill, Peter; Grigoropoulos, Costas P.; Healy, Kevin E.

    2015-09-01

    Although adhesive interactions between cells and nanostructured interfaces have been studied extensively, there is a paucity of data on how nanostructured interfaces repel cells by directing cell migration and cell-colony organization. Here, by using multiphoton ablation lithography to pattern surfaces with nanoscale craters of various aspect ratios and pitches, we show that the surfaces altered the cells’ focal-adhesion size and distribution, thus affecting cell morphology, migration and ultimately localization. We also show that nanocrater pitch can disrupt the formation of mature focal adhesions to favour the migration of cells towards higher-pitched regions, which present increased planar area for the formation of stable focal adhesions. Moreover, by designing surfaces with variable pitch but constant nanocrater dimensions, we were able to create circular and striped cellular patterns. Our surface-patterning approach, which does not involve chemical treatments and can be applied to various materials, represents a simple method to control cell behaviour on surfaces.

  7. Plasma membrane protein trafficking in plant-microbe interactions: a plant cell point of view

    Directory of Open Access Journals (Sweden)

    Nathalie eLeborgne-Castel

    2014-12-01

    Full Text Available In order to ensure their physiological and cellular functions, plasma membrane (PM proteins must be properly conveyed from their site of synthesis, i.e. the endoplasmic reticulum, to their final destination, the PM, through the secretory pathway. PM protein homeostasis also relies on recycling and/or degradation, two processes that are initiated by endocytosis. Vesicular membrane trafficking events to and from the PM have been shown to be altered when plant cells are exposed to mutualistic or pathogenic microbes. In this review, we will describe the fine-tune regulation of such alterations, and their consequence in PM protein activity. We will consider the formation of intracellular perimicrobial compartments, the PM protein trafficking machinery of the host, and the delivery or retrieval of signaling and transport proteins such as pattern-recognition receptors, producers of reactive oxygen species, and sugar transporters.

  8. Toward Synthetic Spatial Patterns in Engineered Cell Populations with Chemotaxis.

    Science.gov (United States)

    Duran-Nebreda, Salva; Solé, Ricard V

    2016-07-15

    A major force shaping form and patterns in biology is based in the presence of amplification mechanisms able to generate ordered, large-scale spatial structures out of local interactions and random initial conditions. Turing patterns are one of the best known candidates for such ordering dynamics, and their existence has been proven in both chemical and physical systems. Their relevance in biology, although strongly supported by indirect evidence, is still under discussion. Extensive modeling approaches have stemmed from Turing's pioneering ideas, but further confirmation from experimental biology is required. An alternative possibility is to engineer cells so that self-organized patterns emerge from local communication. Here we propose a potential synthetic design based on the interaction between population density and a diffusing signal, including also directed motion in the form of chemotaxis. The feasibility of engineering such a system and its implications for developmental biology are also assessed. PMID:27009520

  9. Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

    International Nuclear Information System (INIS)

    Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel

  10. Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

    Energy Technology Data Exchange (ETDEWEB)

    Premnath, Priyatha, E-mail: priyatha.premnath@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tavangar, Amirhossein, E-mail: atavanga@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tan, Bo, E-mail: tanbo@ryerson.ca [Nanocharacterization Laboratory, Department of Aerospace Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Venkatakrishnan, Krishnan, E-mail: venkat@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada)

    2015-09-10

    Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel

  11. Plant Size, Spacing Patterns, and Host-Plant Selection in Osyris Quadripartita, a Hemiparasitic Dioecious Shrub

    OpenAIRE

    Carlos M Herrera

    1989-01-01

    (1) Sex ratio, plant size, spatial distribution and host-plant selection have been examined in three south-western Spanish populations of Osyris quadriparrira (Santala­ ceae), a hemiparasitic dioecious shrub of mediterranean habitats. The three populations are distributed along an environmental gradient characterized by variation in water availability and soil fertility. (2) Sex ratios do not depart significantly from 1: 1 in any of the populations studied. There is n...

  12. An epidermis-driven mechanism positions and scales stem cell niches in plants

    Science.gov (United States)

    Gruel, Jérémy; Landrein, Benoit; Tarr, Paul; Schuster, Christoph; Refahi, Yassin; Sampathkumar, Arun; Hamant, Olivier; Meyerowitz, Elliot M.; Jönsson, Henrik

    2016-01-01

    How molecular patterning scales to organ size is highly debated in developmental biology. We explore this question for the characteristic gene expression domains of the plant stem cell niche residing in the shoot apical meristem. We show that a combination of signals originating from the epidermal cell layer can correctly pattern the key gene expression domains and notably leads to adaptive scaling of these domains to the size of the tissue. Using live imaging, we experimentally confirm this prediction. The identified mechanism is also sufficient to explain de novo stem cell niches in emerging flowers. Our findings suggest that the deformation of the tissue transposes meristem geometry into an instructive scaling and positional input for the apical plant stem cell niche.

  13. An epidermis-driven mechanism positions and scales stem cell niches in plants.

    Science.gov (United States)

    Gruel, Jérémy; Landrein, Benoit; Tarr, Paul; Schuster, Christoph; Refahi, Yassin; Sampathkumar, Arun; Hamant, Olivier; Meyerowitz, Elliot M; Jönsson, Henrik

    2016-01-01

    How molecular patterning scales to organ size is highly debated in developmental biology. We explore this question for the characteristic gene expression domains of the plant stem cell niche residing in the shoot apical meristem. We show that a combination of signals originating from the epidermal cell layer can correctly pattern the key gene expression domains and notably leads to adaptive scaling of these domains to the size of the tissue. Using live imaging, we experimentally confirm this prediction. The identified mechanism is also sufficient to explain de novo stem cell niches in emerging flowers. Our findings suggest that the deformation of the tissue transposes meristem geometry into an instructive scaling and positional input for the apical plant stem cell niche. PMID:27152324

  14. Termination pattern of nanocrystalline diamond controls cell behavior

    Czech Academy of Sciences Publication Activity Database

    Brož, A.; Ukraintsev, Egor; Babchenko, Oleg; Kromka, Alexander; Rezek, Bohuslav; Verdánová, M.; Ostrovská, L.; Sauerová, P.; Hubálek Kalbáčová, M.

    Praha : Czechoslovak microscopy society, 2014 - (Hozák, P.) ISBN 978-80-260-6720-7. [ International Microscopy Congress /18./. 07.09.2014-12.09.2014, Praha] R&D Projects: GA ČR GAP108/12/0996; GA ČR(CZ) GA14-04790S Institutional support: RVO:68378271 Keywords : diamond films * patterned surface * surface termination * cell adhesion Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Using Tissue Culture To Investigate Plant Cell Differentiation and Dedifferentiation.

    Science.gov (United States)

    Bozzone, Donna M.

    1997-01-01

    Describes an experimental project that uses plant tissue culture techniques to examine cell differentiation in the carrot. Allows students to gain experience in some important techniques and to explore fundamental questions about cell differentiation. (DDR)

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

    OpenAIRE

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

    2013-01-01

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

  17. Mechanistic Framework for Establishment, Maintenance, and Alteration of Cell Polarity in Plants

    Directory of Open Access Journals (Sweden)

    Pankaj Dhonukshe

    2012-01-01

    Full Text Available Cell polarity establishment, maintenance, and alteration are central to the developmental and response programs of nearly all organisms and are often implicated in abnormalities ranging from patterning defects to cancer. By residing at the distinct plasma membrane domains polar cargoes mark the identities of those domains, and execute localized functions. Polar cargoes are recruited to the specialized membrane domains by directional secretion and/or directional endocytic recycling. In plants, auxin efflux carrier PIN proteins display polar localizations in various cell types and play major roles in directional cell-to-cell transport of signaling molecule auxin that is vital for plant patterning and response programs. Recent advanced microscopy studies applied to single cells in intact plants reveal subcellular PIN dynamics. They uncover the PIN polarity generation mechanism and identified important roles of AGC kinases for polar PIN localization. AGC kinase family members PINOID, WAG1, and WAG2, belonging to the AGC-3 subclass predominantly influence the polar localization of PINs. The emerging mechanism for AGC-3 kinases action suggests that kinases phosphorylate PINs mainly at the plasma membrane after initial symmetric PIN secretion for eventual PIN internalization and PIN sorting into distinct ARF-GEF-regulated polar recycling pathways. Thus phosphorylation status directs PIN translocation to different cell sides. Based on these findings a mechanistic framework evolves that suggests existence of cell side-specific recycling pathways in plants and implicates AGC3 kinases for differential PIN recruitment among them for eventual PIN polarity establishment, maintenance, and alteration.

  18. Plant diversity-productivity patterns in the alpine steppe environment of the Central Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The biodiversity-productivity relationship is an important topic in the research of bio- diversity and ecosystem function. The plant diversity-productivity pattern is commonly unimodal and positively correlated. This paper researches the characteristics of plant diversity-productivity patterns in the Bayanbuluk alpine steppe in the central Tianshan Mountains, Xinjiang, China, and analyzes the effects of environmental factors on the distribution of plant communities, species composition, plant diversity and productivity in the steppe. The results show a positive correlation between plant diversity and productivity. DCCA (detrended canonical correspondence analysis) ordination reveals a significant relationship between the effects of air temperature, soil moisture content, available soil nitrogen, relative humidity and pH value on the distribution and composition of plant communities. There are significant correlations between the soil moisture content, relative humidity, pH value, air temperature and species richness and the aboveground biomass of Gramineae and Cyperaceae, and also significant correlations between the relative humidity, pH values and the total aboveground biomass of plant communities.

  19. A Quantitative and Dynamic Model for Plant Stem Cell Regulation

    OpenAIRE

    Geier, Florian; Lohmann, Jan U.; Gerstung, Moritz; Maier, Annette T.; Timmer, Jens; Fleck, Christian

    2008-01-01

    Plants maintain pools of totipotent stem cells throughout their entire life. These stem cells are embedded within specialized tissues called meristems, which form the growing points of the organism. The shoot apical meristem of the reference plant Arabidopsis thaliana is subdivided into several distinct domains, which execute diverse biological functions, such as tissue organization, cell-proliferation and differentiation. The number of cells required for growth and organ formation changes ov...

  20. Distribution patterns of medicinal plants along an elevational gradient in central Himalaya, Nepal

    Czech Academy of Sciences Publication Activity Database

    Rokaya, Maan Bahadur; Münzbergová, Zuzana; Shrestha, M.R.; Timsina, B.

    2012-01-01

    Roč. 9, č. 2 (2012), s. 201-213. ISSN 1672-6316 R&D Projects: GA ČR GA526/09/0549 Institutional research plan: CEZ:AV0Z60050516 Keywords : distribution patterns * medicinal plants * unimodal relationships Subject RIV: EF - Botanics Impact factor: 0.664, year: 2012

  1. Control of the pattern-recognition receptor EFR by an ER protein complex in plant immunity

    DEFF Research Database (Denmark)

    Nekrasov, Vladimir; Li, Jing; Batoux, Martine; Roux, Milena; Chu, Zhao-Hui; Lacombe, Severine; Rougon, Alejandra; Bittel, Pascal; Kiss-Papp, Marta; Chinchilla, Delphine; van Esse, H Peter; Jorda, Lucia; Schwessinger, Benjamin; Nicaise, Valerie; Thomma, Bart P H J; Molina, Antonio; Jones, Jonathan D G; Zipfel, Cyril

    2009-01-01

    In plant innate immunity, the surface-exposed leucine-rich repeat receptor kinases EFR and FLS2 mediate recognition of the bacterial pathogen-associated molecular patterns EF-Tu and flagellin, respectively. We identified the Arabidopsis stromal-derived factor-2 (SDF2) as being required for EFR...

  2. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

  3. Model Optimization Planting Pattern Agroforestry Forest Land Based on Pine Tree

    Science.gov (United States)

    Rajati, Tati

    2015-01-01

    This study aims to determine cropping patterns in class slopes 0 - 30%. The method used in this study is a description of the dynamic system approach using a software power sim. Forest areas where the research, which is a type of plant that is cultivated by the people in the study…

  4. A study on the operator's communication pattern characteristics under abnormal operating situation of nuclear power plants

    International Nuclear Information System (INIS)

    The quality of a probabilistic safety assessment (PSA) has become more important and a human reliability analysis (HRA) is known as a major contributor to the uncertainty of a PSA. As a part of enhancing the HRA quality, a study was initiated to find out characteristics of communication pattern and to evaluate communication quality of the operators of nuclear power plants. Korea Atomic Energy Research Institute (KAERI) is developing evaluation methods for the effect of human-induced events on risk/performance. This paper describes a study on the operator's communication pattern characteristics under abnormal operating situation of nuclear power plants. The study was carried out in four stages; 1) Video recording 2) Audio scripting 3) Message Classification 4) Communication Pattern Analysis. We recorded eight abnormal simulator training programs from Younggwang nuclear power plant training center. After that we performed message classification and carried out communication pattern analysis. We compared communication patterns of abnormal operating situation with emergency operating situation.As results of analysis, the role of SRO (senior reactor operator) under abnormal operating situation was decreased than the activities under emergency operating situation because each operator (reactor operator, turbine operator, safety supervisor) in main control room (MCR) performs the activity to control by himself with corresponding field engineers with his basic knowledge of the system. On the other hand, the operator's decision making processes and activities under abnormal operating situation were dramatically increased than the emergency operating situation. (authors)

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

    OpenAIRE

    Daniela eBellincampi; Felice eCervone; Vincenzo eLionetti

    2014-01-01

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

  6. Cellulose microfibril assembly and orientation in higher plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.C. (Syracuse Univ., NY); Maclachlan, G.A.; Brown, R.M. Jr.

    1983-01-01

    Freeze-fractured plasma membranes of seedlings of Zea mays L., Burpee's Snowcross, and Pisum sativum L., variety Alsaka, contain terminal complex structures and the impressions of microfibrils from the newest cell wall layer.Terminal complex subunits are on the exoplasmic fracture (EF) face, and rosette subunits are on the protoplasmic fracture (PF) face of the membrane. The association of terminal complexes and rosettes with microfibril tips and their association with newly deposited groups of microfibrils is indirect evidence for their role in microfibril assembly. Microtubules may be responsible for certain orientations of microfibrils, particularly the formation of bands of microfibrils in newly deposited wall layers. However, microfibril orienting mechanisms are more complex, involving factors still present during colchicine treatment. Since UDP-glucose is thought to be a precursor of cellulose microfibrils in higher plant cells, EM radioautography was used to determine the site of incorporation of glucose. However, under the conditions used, glucose was only incorporated from UDP-glucose at the surface of cut or damaged pea stem cells, i.e., in vitro. Thus, incorporation of glucose from UDP-glucose was not useful for probing the patterns of cellulose microfibril synthesis in vivo. 18 references, 8 figures.

  7. The First Observation on Plant Cell Fossils in China

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; CUI Jinzhong

    2007-01-01

    For a long time, paleontologists have been focusing on hard parts of organisms during different geological periods while soft parts are rarely reported. Well-preserved plant cells, if found in fossils, are treated only as a rarity. Recent progress in research on fossil cytoplasm indicates that plant cytoplasm not only has excellent ultrastructures preserved but also may be a quite commonly seen fossil in strata. However, up to now there is no report of plant cell fossils in China yet. Here plant cell fossils are reported from Huolinhe Coal Mine (the early Cretaceous), Inner Mongolia, China. The presence of plant cytoplasm fossils in two cones on the same specimen not only provides further support for the recently proposed hypothesis on plant cytoplasm fossilization but also marks the first record of plant cytoplasm fossils in China, which suggests a great research potential in this new area.

  8. Progress and prospects for phosphoric acid fuel cell power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bonville, L.J.; Scheffler, G.W.; Smith, M.J. [International Fuel Cells Corp., South Windsor, CT (United States)

    1996-12-31

    International Fuel Cells (IFC) has developed the fuel cell power plant as a new, on-site power generation source. IFC`s commercial fuel cell product is the 200-kW PC25{trademark} power plant. To date over 100 PC25 units have been manufactured. Fleet operating time is in excess of one million hours. Individual units of the initial power plant model, the PC25 A, have operated for more than 30,000 hours. The first model {open_quotes}C{close_quotes} power plant has over 10,000 hours of operation. The manufacturing, application and operation of this power plant fleet has established a firm base for design and technology development in terms of a clear understanding of the requirements for power plant reliability and durability. This fleet provides the benchmark against which power plant improvements must be measured.

  9. Root cell patterning: a primary target for aluminium toxicity in maize.

    Science.gov (United States)

    Doncheva, Snezhanka; Amenós, Montserrat; Poschenrieder, Charlotte; Barceló, Juan

    2005-04-01

    The short-term influence (5-180 min) of 50 microM Al on cell division was investigated in root tips of two Zea mays L. varieties differing in Al-resistance. The incorporation of bromodeoxyuridine into S-phase nuclei was visualized by immunofluorescence staining using confocal laser fluorescence microscopy. In Al-sensitive plants 5 min Al exposure was enough to inhibit cell division in the proximal meristem (250-800 microm from the tip). After 10 or 30 min with Al only, a few S-phase nuclei were found in the cortical initials. By contrast, cell division was stimulated in the distal elongation zone (2.5-3.1 mm). After 180 min the protrusion of an incipient lateral root was observed in this zone. These observations suggest a fast change in cell patterning rather than a general cariotoxic effect after exposure to Al for a short time. No such changes were found in Al-resistant maize. This is the first report showing such fast Al-induced alterations in the number and the position of dividing cells in root tips. The observation that similar changes were induced by a local supply of naphthylphthalamic acid to the distal transition zone suggests that inhibition of auxin transport plays a role in the Al-induced alteration of root cell patterning. PMID:15737983

  10. The study of accumulation of Sr 90 by plant cells

    International Nuclear Information System (INIS)

    In this work the absorption and desorption of ions Sr 90 by plant cells and influence of different physical and chemical factors of environment on that processes were investigated. The kinetics of strontium accumulation have been obtained and the factors of accumulation of Sr 90 have been determined for a plant cell itself and its separate compartments

  11. Plant programmed cell death, ethylene and flower senescence

    NARCIS (Netherlands)

    Woltering, E.J.; Jong, de A.; Hoeberichts, F.A.; Iakimova, E.T.; Kapchina, V.

    2005-01-01

    Programmed cell death (PCD) applies to cell death that is part of the normal life of multicellular organisms. PCD is found throughout the animal and plant kingdoms; it is an active process in which a cell suicide pathway is activated resulting in controlled disassembly of the cell. Most cases of PCD

  12. Dynamics and Regulation of Actin Cytoskeleton in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Ren Haiyun

    2007-01-01

    @@ The actin cytoskeleton constituted of globular actin (G-actin) is a ubiquitous component of eukaryotic cells and plays crucial roles in diverse physiological processes in plant cells, such as cytoplasmic streaming, organelle and nucleus positioning, cell morphogenesis, cell division, tip growth, etc.

  13. Vascular plant diversity on the roof of the world: Spatial patterns and environmental determinants

    Institute of Scientific and Technical Information of China (English)

    Ling-Feng MAO; Sheng-Bin CHEN; Jin-Long ZHANG; Yan-Hui HOU; Guang-Sheng ZHOU; Xin-Shi ZHANG

    2013-01-01

    The Qinghai-Tibetan Plateau (QTP),known as "the Roof of the World",is one of the most unique and vulnerable biodiversity regions on Earth.However,the spatial patterns and determinants of vascular plant diversity on the QTP are still poorly documented,despite a number of publications focusing on its flora.Using extensively compiled data gathered from local flora and specimen records,we evaluated the relative importance of water,energy,and habitat heterogeneity-related variables in shaping the distribution of vascular plant diversity (species,genus,family,herb,woody plants).We found that higher richness always occurred in the south and east of the QTP,especially along the Himalayas,and that habitat heterogeneity,water,and energy variables are important determinants of vascular plant richness patterns on the QTP.The explanatory power of most single predictors was obviously different across life forms,with woody plant richness generally more sensitive to most environmental factors than herb richness.In addition,the explanatory power of habitat heterogeneity models,combined water and energy models,and environmental models increased as the taxonomic level increased from species to family.The results highlight that correlations between plant richness and environmental variables vary with life form and taxonomic scale,and suggest that the explanatory power of variables will change in different spatial scales due to the proportion of life forms and the asymmetric effects of these drivers on life form richness.

  14. A Biodiversity Informatics Approach to Ethnobotany: Meta-analysis of Plant Use Patterns in Ecuador

    Directory of Open Access Journals (Sweden)

    Finn Borchsenius

    2012-03-01

    Full Text Available We explored the relative importance of ecosystem diversity, socioeconomic, environmental, and geographical factors in determining the pattern and diversity of people’s plant use in Ecuador, based on existing ethnobotanic investigations and a large database of georeferenced plant collections. For each of 40 communities, we determined the number of plants used and their distribution among 12 use categories. Plant species richness of the ecosystem surrounding each village was determined using herbarium data and rarefaction. Variation in socioeconomic, environmental, and geographical indicator variables at the community level was summarized using Principal Component Analysis (PCA. Data were then analyzed using multiple regression and ordination analysis. We found a significant positive relationship between the number of plant species used and ecosystem species richness, whereas socioconomic, environmental, and geographical factors had no significance. However, ordination analysis did show a clear link among these factors and plant use patterns, i.e., the relative importance of different use categories. Study communities were divided into two groups: 1 Andean and coastal communities with better access to public services and markets categorized by high scores in these use classes: medicinal, social, food additives, environmental, apicolous (of economic interest in apiculture, and toxic to nonvertebrates; and 2 Amazonian remote communities with high scores for these use classes: food, fuel, materials, vertebrate and invertebrate food, and toxic to vertebrates. Our findings suggest that economic and social development affects plant use patterns in a selective way. Some traditional uses will persist despite increased infrastructure development and habitat disturbance, whereas others that reflect subsistence strategies dependent on conserved natural habitats may soon disappear. The study incorporates more than 20 years of ethnobotanical research effort

  15. Cell wall integrity signaling and innate immunity in plants

    OpenAIRE

    Nühse, Thomas S.

    2012-01-01

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

  16. Laser-based patterning for transfected cell microarrays

    International Nuclear Information System (INIS)

    The spatial control over biomolecule- and cell-surface interactions is of great interest to a broad range of biomedical applications, including sensors, implantable devices and cell microarrays. Microarrays in particular require precise spatial control and the formation of patterns with microscale features. Here, we have developed an approach specifically designed for transfected cell microarray (TCM) applications that allows microscale spatial control over the location of both DNA and cells on highly doped p-type silicon substrates. This was achieved by surface modification, involving plasma polymerization of allylamine, grafting of poly(ethylene glycol) and subsequent excimer laser ablation. DNA could be delivered in a spatially defined manner using ink-jet printing. In addition, electroporation was investigated as an approach to transfect attached cells with adsorbed DNA and good transfection efficiencies of approximately 20% were observed. The ability of the microstructured surfaces to spatially direct both DNA adsorption and cell attachment was demonstrated in a functional TCM, making this system an exciting platform for chip-based functional genomics.

  17. Laser-based patterning for transfected cell microarrays

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Andrew L; Creasey, Rhiannon; Voelcker, Nicolas H [Flinders University, GPO Box 2100, Bedford Park, SA 5042 (Australia); Hayes, Jason P [MiniFAB, 1 Dalmore Drive, Caribbean Park, Scoresby VIC 3179 (Australia); Thissen, Helmut, E-mail: Nico.Voelcker@flinders.edu.a [CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168 (Australia)

    2009-12-15

    The spatial control over biomolecule- and cell-surface interactions is of great interest to a broad range of biomedical applications, including sensors, implantable devices and cell microarrays. Microarrays in particular require precise spatial control and the formation of patterns with microscale features. Here, we have developed an approach specifically designed for transfected cell microarray (TCM) applications that allows microscale spatial control over the location of both DNA and cells on highly doped p-type silicon substrates. This was achieved by surface modification, involving plasma polymerization of allylamine, grafting of poly(ethylene glycol) and subsequent excimer laser ablation. DNA could be delivered in a spatially defined manner using ink-jet printing. In addition, electroporation was investigated as an approach to transfect attached cells with adsorbed DNA and good transfection efficiencies of approximately 20% were observed. The ability of the microstructured surfaces to spatially direct both DNA adsorption and cell attachment was demonstrated in a functional TCM, making this system an exciting platform for chip-based functional genomics.

  18. Scale- and taxon-dependent patterns of plant diversity in steppes of Khakassia, South Siberia (Russia)

    DEFF Research Database (Denmark)

    Polyakova, M.A.; Dembicz, I; Becker, T;

    2016-01-01

    Palaearctic? (ii) What are the main environmental drivers of the diversity patterns in these steppes? (iii) What are the diversity-environment relationships and do they vary between spatial scales and among different taxonomic groups? We sampled the steppe vegetation (vascular plants, bryophytes and lichens....... Total species richness was controlled predominantly by heat load index, mean annual precipitation, humus content and soil skeleton content. The positive role of soil pH was evident only for vascular plant species richness. Similar to other studies, we found that the importance of environmental factors......The drivers of plant richness at fine spatial scales in steppe ecosystems are still not sufficiently understood. Our main research questions were: (i) How rich in plant species are the natural steppes of Southern Siberia compared to natural and semi-natural grasslands in other regions of the...

  19. Apoptosis-Inducing Effect of Three Medicinal Plants on Oral Cancer Cells KB and ORL-48

    Directory of Open Access Journals (Sweden)

    Mohd Zabidi Majid

    2014-01-01

    Full Text Available Brucea javanica, Azadirachta indica, and Typhonium flagelliforme are medicinal plants commonly used to treat conditions associated with tumour formation. This study aimed to determine the antiproliferative activity of these plants extracts on KB and ORL-48 oral cancer cell lines and to suggest their mode of cell death. The concentration producing 50% cell inhibition (IC50 was determined and the activity was examined under an inverted microscope. Immunohistochemistry fluorescent staining method (TUNEL was performed to indicate the mechanism of cell death and the fragmented DNA band pattern produced was obtained for verification. Compared to Azadirachta sp. and Typhonium sp., the antiproliferative activity of Brucea sp. extract was the most potent on both KB and ORL-48 cells with IC50 of 24.37 ± 1.75 and 6.67 ± 1.15 µg/mL, respectively. Signs of cell attrition were observed 24 hr after treatment. Green fluorescent spots indicating cell death by apoptosis were observed in images of both cells following treatment with all the three extracts. DNA fragments harvested from Brucea-treated cells produced bands in a ladder pattern suggesting the apoptotic effect of the extract. It is thus concluded that Brucea sp. extract exhibited cytotoxic activity on ORL-48 cells and their action mechanism is via apoptosis.

  20. The Untapped Potential Of Plant Thin Cell Layers

    OpenAIRE

    Teixeira da Silva Jaime; Altamura Maria Maddalena; Dobránszki Judit

    2015-01-01

    Thin cell layers (TCLs), which contain a small number of cells or tissues, are explants excised from different organs (stems, leaves, roots, inflorescences, flowers, cotyledons, hypocotyls/epicotyls, and embryos). After almost 45 years of research, this culture system has been used for several monocotyledonous and dicotyledonous plants of commercial importance, and for model plants. The limited amount of cells in a TCL is of paramount importance because marker molecules/genes of differentiati...

  1. Super-resolution Microscopy in Plant Cell Imaging.

    Science.gov (United States)

    Komis, George; Šamajová, Olga; Ovečka, Miroslav; Šamaj, Jozef

    2015-12-01

    Although the development of super-resolution microscopy methods dates back to 1994, relevant applications in plant cell imaging only started to emerge in 2010. Since then, the principal super-resolution methods, including structured-illumination microscopy (SIM), photoactivation localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), and stimulated emission depletion microscopy (STED), have been implemented in plant cell research. However, progress has been limited due to the challenging properties of plant material. Here we summarize the basic principles of existing super-resolution methods and provide examples of applications in plant science. The limitations imposed by the nature of plant material are reviewed and the potential for future applications in plant cell imaging is highlighted. PMID:26482957

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

    Directory of Open Access Journals (Sweden)

    Gabriel Paës

    2014-07-01

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

  3. The Glycoprofile Patterns of Endothelial Cells in Usual Interstitial Pneumonia

    Directory of Open Access Journals (Sweden)

    A Barkhordari

    2014-09-01

    Full Text Available [THIS ARTICLE HAS BEEN RETRACTED FOR DUPLICATE PUBLICATION] Background: The pathological classification of cryptogenic fibrosing alveolitis has been a matter of debate and controversy for histopathologists.Objective: To identify and specify the glycotypes of capillary endothelial cells in usual interstitial pneumonia (UIP compared to those found in normal tissue.Methods: Sections of formalin-fixed, paraffin-embedded blocks from 16 cases of UIP were studied by lectin histochemistry with a panel of 27 biotinylated lectins and an avidin-peroxidase revealing system.Results: High expression of several classes of glycan was seen de novo in capillary endothelial cells from patients with UIP including small complex and bi/tri-antennary bisected complex N-linked sequences bolund by Concanavalin A and erythro-phytohemagglutinin, respectively, GalNAca1 residues bound by Helix pomatia and Maclura pomifera agglutinins, and L-fucosylated derivatives of type II glycan chains recognized by Ulex europaeus agglutinin-I. Glycans bound by agglutinins from Lycopersicon esculentum (β1,4GlcNAc and Wisteria floribunda (GalNAc as well as GlcNAc oligomers bound by Phytolacca americana and succinylated Wheat Germ agglutinin were also seen in the capillary endothelial cells of UIP. In contrast, L-fucosylated derivatives of type I glycan chains were absent in cells from cases of UIP when Anguilla anguilla agglutinin was applied, unlike the situation in normal tissue.Conclusion: These results may indicate existence of two distinct populations of endothelial cell in UIP with markedly different patterns of glycosylation, reflecting a pattern of differentiation and angiogenesis, which is not detectable morphologically.

  4. An algorithm about spatial association rule mining based on cell pattern

    Science.gov (United States)

    Chen, Jiangping; Li, Pingxiang; Fei, Huang; Wang, Rong

    2006-10-01

    Spatial association rule is one of the upmost knowledge rules in the result of spatial data mining. It emphasizes particularly on confirming the relation of data in different fields. It tries to find out the dependence of data in multi-fields. As we know, in GIS the spatial database is often separated into several layers or tables according the type of the spatial object such as road layer, building layer, plant layer etc. In the relational database we often separate it into several tables which be associated by the primary key and foreign key according the normal form theory. Consequently, the spatial data is stored in different layers and tables. It is necessary and meaning to mining the knowledge and rules in multi-layer and multi-tables. And, It is inevitable to mining spatial association rules in multi-layer in some application. There is a problem in it, that is the number of the rules are magnitude. So, we point a new way by using the cell pattern of the rules which the user interested to reduce and simplify the operation. In this paper the concept of multi-layer spatial association rule is put forward. Then an algorithm of mining multi-layer spatial association rule is presented which based on cell pattern and spatial concept relation. It was called AP-MLSAM in the paper. Last, an example in GIS is given. In AP-MLSAM, First, it confirms the patterns and rules that the user is interested in. Second it counts the large itemsets according with the cell pattern in each data layer. Last, the spatial association rules are gained by the itemsets which be counted in the second step. From the experiment, it proved that AP-MLSAM is effective. It improved the efficiency by reducing the time of finding the large itemsets. It is a significance research field for mining multi-layer spatial association rules. There are many applications based on multi-layer spatial association analyse. For example: traffic flux analyse in city, weather pattern analyse, trend analyse for

  5. Incorporation of mammalian actin into microfilaments in plant cell nucleus

    Directory of Open Access Journals (Sweden)

    Paves Heiti

    2004-04-01

    Full Text Available Abstract Background Actin is an ancient molecule that shows more than 90% amino acid homology between mammalian and plant actins. The regions of the actin molecule that are involved in F-actin assembly are largely conserved, and it is likely that mammalian actin is able to incorporate into microfilaments in plant cells but there is no experimental evidence until now. Results Visualization of microfilaments in onion bulb scale epidermis cells by different techniques revealed that rhodamine-phalloidin stained F-actin besides cytoplasm also in the nuclei whereas GFP-mouse talin hybrid protein did not enter the nuclei. Microinjection of fluorescently labeled actin was applied to study the presence of nuclear microfilaments in plant cells. Ratio imaging of injected fluorescent rabbit skeletal muscle actin and phalloidin staining of the microinjected cells showed that mammalian actin was able to incorporate into plant F-actin. The incorporation occurred preferentially in the nucleus and in the perinuclear region of plant cells whereas part of plant microfilaments, mostly in the periphery of cytoplasm, did not incorporate mammalian actin. Conclusions Microinjected mammalian actin is able to enter plant cell's nucleus, whereas incorporation of mammalian actin into plant F-actin occurs preferentially in the nucleus and perinuclear area.

  6. PECULIARITIES OF SECONDARY METABOLITES BIOSYNTHESIS IN PLANT CELL CULTURES

    Directory of Open Access Journals (Sweden)

    A.M. NOSOV

    2014-06-01

    Full Text Available metabolites formation in plant cell cultures of Panax spp., (ginsenosides; Dioscorea deltoidea (steroid glycosides; Ajuga reptans, Serratula coronata, Rhaponticum carthamoides (ecdisteroids; Polyscias spp., (triterpene glycosides, Taxus spp. (taxoids, Stevia rebaudiana (diterpene steviol-glycosides, Stephania glabra (alkaloids. They are some regular trends of secondary metabolites synthesis in the plant cell culture:It can be noted the stable synthesis of the compound promoting cell proliferation. Indeed, cell cultures of Dioscorea deltoidea were demonstrated to accumulate only furostanol glycosides, which promoted cell division. Furostanol glycoside content of Dioscorea strain DM-0.5 was up to 6 - 12% by dry biomass.Panax ginseng and P. japonicus plant cell cultures synthesize as minimum seven triterpene glycosides (ginsenosides, the productivity of these compounds was up to 6.0 - 8.0% on dry biomass.By contrast, the detectable synthesis of diterpene steviol-glycosides in cultivated cells of Stevia rebaudiana initiated in the mixotrophic cultures during chloroplast formation only.Despite these differences, or mainly due to them, plant cell cultures have become an attractive source of phytochemicals in alternative to collecting wild plants. It provides a guideline to bioreactor-based production of isoprenoids using undifferentiated plant cell cultures. 

  7. Oesophageal epithelial cell proliferation and food consumption patterns following irradiation

    International Nuclear Information System (INIS)

    The murine data presented illustrate the influence of food consumption on the proliferative rate of the oesophageal epithelium during recovery from radiation damage. Refeeding at a time before the initiation of the normal hyperplastic response results in a decreased time interval between treatment and increased rates of cell proliferation, while reduced food consumption during the normal period of hyperproliferation results in reduced proliferative activity. The finding that recovery kinetics may be altered by changing food consumption patterns should be an important consideration in the analysis of antineoplastic agent-induced proliferative perturbations, as many treatments themselves produce reduced levels of food consumption. (UK)

  8. Pyro-electrification of polymer membranes for cell patterning

    Science.gov (United States)

    Rega, R.; Gennari, O.; Mecozzia, L.; Grilli, S.; Pagliarulo, V.; Ferraro, P.

    2016-05-01

    In the recent years, much attention has been devoted to the possibility of charging polymer-based materials, due to their potential in developing large-scale and inexpensive flexible thin-film technology. The availability of localized electrostatic fields is in of great interest for a huge amount of applications such as distribution of biomolecules and cells from the liquid phase. Here we report a voltage-free pyro-electrification (PE) process able to induce permanent dipoles into polymer layers; the lithium niobate (LN) crystal is the key component that plays the multi-purpose role of sustaining, heating and poling the polymer layer that is then peeled-off easily in order to have a free-standing charged membrane. The results show the fascinating application for the living cell patterning. It well known that cell behaviour is affected by chemical and topographical cues of substrate. In fact, polymers, such as polystyrene (PS) and poly(methyl methacrylate) (PMMA), are naturally cytophobic and require specific functionalization treatments in order to promote cell adhesion. Through our proposal technique, it's possible to obtain spontaneous organization and a driven growth of SH-SY5Y cells that is solely dictated by the nature of the charge polymer surface, opening, in this way, the innovative chance to manipulate and transfer biological samples on a free-standing polymer layer [1].

  9. Distribution pattern of rare plants along riparian zone in Shennongjia Area

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m×100 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200-1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.

  10. Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns.

    Science.gov (United States)

    Benedetti, Manuel; Pontiggia, Daniela; Raggi, Sara; Cheng, Zhenyu; Scaloni, Flavio; Ferrari, Simone; Ausubel, Frederick M; Cervone, Felice; De Lorenzo, Giulia

    2015-04-28

    Oligogalacturonides (OGs) are fragments of pectin that activate plant innate immunity by functioning as damage-associated molecular patterns (DAMPs). We set out to test the hypothesis that OGs are generated in planta by partial inhibition of pathogen-encoded polygalacturonases (PGs). A gene encoding a fungal PG was fused with a gene encoding a plant polygalacturonase-inhibiting protein (PGIP) and expressed in transgenic Arabidopsis plants. We show that expression of the PGIP-PG chimera results in the in vivo production of OGs that can be detected by mass spectrometric analysis. Transgenic plants expressing the chimera under control of a pathogen-inducible promoter are more resistant to the phytopathogens Botrytis cinerea, Pectobacterium carotovorum, and Pseudomonas syringae. These data provide strong evidence for the hypothesis that OGs released in vivo act as a DAMP signal to trigger plant immunity and suggest that controlled release of these molecules upon infection may be a valuable tool to protect plants against infectious diseases. On the other hand, elevated levels of expression of the chimera cause the accumulation of salicylic acid, reduced growth, and eventually lead to plant death, consistent with the current notion that trade-off occurs between growth and defense. PMID:25870275

  11. Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

    DEFF Research Database (Denmark)

    Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

    2015-01-01

    Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... by initial dominance of D. flexuosa. The observed inter-annual variability in climatic conditions (summer precipitation and soil water content) affected both species in a similar way and did not substantially alter the competitive balance between the species. Our study supports the “successional mosaic...

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

    OpenAIRE

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

    2010-01-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the s...

  13. Vital Autofluorescence: Application to the Study of Plant Living Cells

    OpenAIRE

    Roshchina, Victoria V.

    2012-01-01

    The application of various microscopy methods such as luminescence microscopy, microspectrofluorimetry and laser-scanning confocal microscopy has been considered as an approach to study the autofluorescence of plant living cells—from cell diagnostics up to modelling the cell-cell contacts and cell interactions with fluorescent biologically active substances. It bases on the direct observations of secretions released from allelopathic and medicinal species and the cell-donor interactions with ...

  14. RhizoFlowCell system reveals early effects of micropollutants on aquatic plant rhizosphere.

    Science.gov (United States)

    Mynampati, Kalyan Chakravarthy; Lee, Yong Jian; Wijdeveld, Arjan; Reuben, Sheela; Samavedham, Lakshminarayanan; Kjelleberg, Staffan; Swarup, Sanjay

    2015-12-01

    In aquatic systems, one of the non-destructive ways to quantify toxicity of contaminants to plants is to monitor changes in root exudation patterns. In aquatic conditions, monitoring and quantifying such changes are currently challenging because of dilution of root exudates in water phase and lack of suitable instrumentation to measure them. Exposure to pollutants would not only change the plant exudation, but also affect the microbial communities that surround the root zone, thereby changing the metabolic profiles of the rhizosphere. This study aims at developing a device, the RhizoFlowCell, which can quantify metabolic response of plants, as well as changes in the microbial communities, to give an estimate of the stress to which the rhizosphere is exposed. The usefulness of RhizoFlowCell is demonstrated using naphthalene as a test pollutant. Results show that RhizoFlowCell system is useful in quantifying the dynamic metabolic response of aquatic rhizosphere to determine ecosystem health. PMID:26386206

  15. Use of mutation induction to alter the ontogenetic pattern of crop plants

    International Nuclear Information System (INIS)

    Examples of the mutant cultivars with altered flowering or maturity time are given, and the induced mutants with altered developmental patterns are reviewed. It is pointed out that the adjustment of the time of maturity (earliness or lateness) without lowering the highly desirable traits of a variety such as yield and quality is obtainable by induced mutation techniques. Earlier harvest and the shorter duration from sowing to harvest generally leads to lower yield, but this may be tolerated if better quality is achieved, if crops escape hazardous stress conditions or pathogen attack, and if the subsequent crops gain in yield. Some examples in barley, wheat, rice, leguminous plants, oil seed and fiber crops, sugar cane, fruits and ornamentals are reviewed, and it is emphasized that the whole life history of plants has relevance for their productivity, and that the careful examination of ontogenetic pattern is necessary to breed desirable varieties. (Kaihara, S.)

  16. Before the 'Big Chill': Patterns of plant-insect associations from the Neogene of Iceland

    Science.gov (United States)

    Wappler, Torsten; Grímsson, Friðgeir

    2016-07-01

    Iceland is the only known terrestrial place in the subarctic North Atlantic providing a fairly continuous sedimentary and plant fossil record over the past 15 million years. While the basic palaeobotanical framework of this pattern has been well established during the last decade, less attention has been paid to the abundant insect traces on fossil leaves/leaflets. Here, we assess the diversity and frequency of insect herbivory on 4349 fossil angiosperm leaves/leaflets from six plant-bearing sedimentary formations exposed at 18 localities. By combining analyses of environmental factors, species interactions, ecology, biogeography, and the geological history, our results demonstrate how patterns of herbivory have changed over time in relation to temperature fluctuations that profoundly influenced levels of insect-mediated damage diversity and frequency. In addition, higher structural complexity, particularly the establishment of species-rich herb layer communities seems to have positively influenced the structure of insect communities in early late Miocene palaeoforests of Iceland.

  17. On-line critical control rod pattern prediction algorithm for BWR plant startup

    International Nuclear Information System (INIS)

    This paper describes an on-line algorithm for predicting the critical control rod pattern, which has been developed to reduce the mental strain on operators while withdrawing control rods in the BWR plant startup operation. The proposed algorithm estimates a target eigenvalue (eigenvalue bias) for a three-dimensional neutron kinetics model with a neutron source incorporating actual neutron detector readings. The critical control rod pattern is then predicted based on the estimated eigenvalue bias. The algorithm has been verified using data obtained from an actual startup operation on a BWR model-5 plant, and the estimated eigenvalue bias agreed well with the effective multiplication factor at the criticality actually determined from the operator's judgement. (author)

  18. Computational cell model based on autonomous cell movement regulated by cell-cell signalling successfully recapitulates the "inside and outside" pattern of cell sorting

    Directory of Open Access Journals (Sweden)

    Ajioka Itsuki

    2007-09-01

    Full Text Available Abstract Background Development of multicellular organisms proceeds from a single fertilized egg as the combined effect of countless numbers of cellular interactions among highly dynamic cells. Since at least a reminiscent pattern of morphogenesis can be recapitulated in a reproducible manner in reaggregation cultures of dissociated embryonic cells, which is known as cell sorting, the cells themselves must possess some autonomous cell behaviors that assure specific and reproducible self-organization. Understanding of this self-organized dynamics of heterogeneous cell population seems to require some novel approaches so that the approaches bridge a gap between molecular events and morphogenesis in developmental and cell biology. A conceptual cell model in a computer may answer that purpose. We constructed a dynamical cell model based on autonomous cell behaviors, including cell shape, growth, division, adhesion, transformation, and motility as well as cell-cell signaling. The model gives some insights about what cellular behaviors make an appropriate global pattern of the cell population. Results We applied the model to "inside and outside" pattern of cell-sorting, in which two different embryonic cell types within a randomly mixed aggregate are sorted so that one cell type tends to gather in the central region of the aggregate and the other cell type surrounds the first cell type. Our model can modify the above cell behaviors by varying parameters related to them. We explored various parameter sets with which the "inside and outside" pattern could be achieved. The simulation results suggested that direction of cell movement responding to its neighborhood and the cell's mobility are important for this specific rearrangement. Conclusion We constructed an in silico cell model that mimics autonomous cell behaviors and applied it to cell sorting, which is a simple and appropriate phenomenon exhibiting self-organization of cell population. The model

  19. Plant programmed cell death and the point of no return

    NARCIS (Netherlands)

    Doorn, van W.G.

    2005-01-01

    The point of no return during programmed cell death (PCD) is defined as the step beyond which the cell is irreversibly committed to die. Some plant cells can be saved before this point by inducing the formation of functional chloroplasts. A visibly senescent tissue will then become green again and l

  20. Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes.

    OpenAIRE

    Espinar, José L.; García, Luis V.; Clemente Salas, Luis

    2005-01-01

    The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three saltmarsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination pro...

  1. β-glucan: Crucial component of the fungal cell wall and elusive MAMP in plants.

    Science.gov (United States)

    Fesel, Philipp H; Zuccaro, Alga

    2016-05-01

    Plant innate immunity relies in first place on the detection of invading microbes. Thus, plants evolved receptors to sense unique molecules of the microbe, the so called microbe-associated molecular patterns or MAMPs. The best studied fungal MAMP is chitin, an important structural building block of the fungal cell wall. Over the past years several plant receptors for chitin have been characterized as well as different strategies adopted by fungi to evade chitin recognition. Despite its strong activity as an elicitor of plant defense chitin represents only a small percentage of the cell wall of most fungi compared to other complex sugars. β-glucan, the most abundant fungal cell wall polysaccharide, also serves as a MAMP, but the mechanisms of β-glucan perception and signaling in plants are largely unknown. In contrast to that the β-glucan recognition and signaling machineries are well characterized in mammals. The C-type lectin receptor Dectin-1 is a key component of these machineries. In this review we describe valuable knowledge about the existence of at least one β-glucan receptor in plants and about the hindrances in β-glucan research. Additionally we discuss possible future perspectives of glucan research and the possibility to transfer the gathered knowledge from mammalian systems to plants. PMID:26688467

  2. An introduction to plant cell culture: the future ahead.

    Science.gov (United States)

    Loyola-Vargas, Víctor M; Ochoa-Alejo, Neftalí

    2012-01-01

    Plant cell, tissue, and organ culture (PTC) techniques were developed and established as an experimental necessity for solving important fundamental questions in plant biology, but they currently represent very useful biotechnological tools for a series of important applications such as commercial micropropagation of different plant species, generation of disease-free plant materials, production of haploid and doublehaploid plants, induction of epigenetic or genetic variation for the isolation of variant plants, obtention of novel hybrid plants through the rescue of hybrid embryos or somatic cell fusion from intra- or intergeneric sources, conservation of valuable plant germplasm, and is the keystone for genetic engineering of plants to produce disease and pest resistant varieties, to engineer metabolic pathways with the aim of producing specific secondary metabolites or as an alternative for biopharming. Some other miscellaneous applications involve the utilization of in vitro cultures to test toxic compounds and the possibilities of removing them (bioremediation), interaction of root cultures with nematodes or mycorrhiza, or the use of shoot cultures to maintain plant viruses. With the increased worldwide demand for biofuels, it seems that PTC will certainly be fundamental for engineering different plants species in order to increase the diversity of biofuel options, lower the price marketing, and enhance the production efficiency. Several aspects and applications of PTC such as those mentioned above are the focus of this edition. PMID:22610615

  3. The Transport of Ions Across Plant Cell Membranes.

    Science.gov (United States)

    Baker, D. A.

    1981-01-01

    Presented is one of a series of articles designed to help science teachers keep current on ideas in specific areas of biology. This article provides information about ion transport in plant cells. (PB)

  4. The role of gama tubulin in acentrosomal plant cells

    Czech Academy of Sciences Publication Activity Database

    Petrovská; Cenklová, Věra; Procházková, Jiřina; Doskočilová, Anna; Volc, Jindřich; Binarová, Pavla

    2007. s. 35. [Konference experimentální biologie rostlin, dny fyziologie rostlin /11./. 09.07.2007-12.07.2007, Olomouc] Keywords : gama tubulin * acentrosomal plant cells Subject RIV: EB - Genetics ; Molecular Biology

  5. The Role of Plant Hormones in Nematode Feeding Cell Formation

    NARCIS (Netherlands)

    Goverse, A.; Bird, D.

    2011-01-01

    In this Chapter, we discuss recent advances in the role of plant hormones in the molecular mechanisms underlying feeding cell formation both by cyst (CN) and root-knot nematodes (RKN). Phytohormones are small signalling molecules that regulate plant growth and development, including the formation of

  6. Dynamics in the Central Plant Cell Metabolism

    OpenAIRE

    Ampofo-Asiama, Jerry

    2014-01-01

    As part of their development, plants have acquired adaptive mechanisms to cope with different stress situations they encounter in their environment. These adaptive mechanisms include the ability to alter their metabolism when faced with extreme environmental conditions such as low oxygen. In higher plants, oxygen (O2) availability is important for energy production through respiratory metabolism. Under conditions where O2 becomes limiting, respiratory metabolism can be impeded leading to impa...

  7. Plant response to heavy metals and organic pollutants in cell culture and at whole plant level

    Energy Technology Data Exchange (ETDEWEB)

    Golan-Goldhirsh, A.; Barazani, O. [Ben-Gurion Univ. of The Negev, The Jacob Blaustein Inst. for Desert Research, Albert Katz Dept. of Dryland Biotechnologies, Desert Plant Biotechnology Lab., Sede Boqer Campus (Israel); Nepovim, A.; Soudek, P.; Vanek, T. [Inst. of Organic Chemistry and Biochemistry (Czech Republic); Smrcek, S.; Dufkova, L.; Krenkova, S. [Faculty of Natural Sciences, Charles Univ. (Czech Republic); Yrjala, K. [Univ. of Helsinki, Dept. of Biosciences, Div. of General Microbiology, Helsinki (Finland); Schroeder, P. [Inst. for Soil Ecology, GSF National Research Center for Environment and Health, Neuherberg, Oberschleissheim (Germany)

    2004-07-01

    Background. Increasing awareness in the last decade concerning environmental quality had prompted research into 'green solutions' for soil and water remediation, progressing from laboratory in vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see that in vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plant-mycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective. This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress from in vitro tissue culture to whole plant experiments in soil. Results. Results obtained from in vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and recommendations. In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when

  8. Woody plant encroachment into grasslands: spatial patterns of functional group distribution and community development.

    Science.gov (United States)

    Liu, Feng; Archer, Steven R; Gelwick, Frances; Bai, Edith; Boutton, Thomas W; Wu, Xinyuan Ben

    2013-01-01

    Woody plant encroachment into grasslands has been globally widespread. The woody species invading grasslands represent a variety of contrasting plant functional groups and growth forms. Are some woody plant functional types (PFTs) better suited to invade grasslands than others? To what extent do local patterns of distribution and abundance of woody PFTs invading grasslands reflect intrinsic topoedaphic properties versus plant-induced changes in soil properties? We addressed these questions in the Southern Great Plains, United States at a subtropical grassland known to have been encroached upon by woody species over the past 50-100 years. A total of 20 woody species (9 tree-statured; 11 shrub-statured) were encountered along a transect extending from an upland into a playa basin. About half of the encroaching woody plants were potential N2-fixers (55% of species), but they contributed only 7% to 16 % of the total basal area. Most species and the PFTs they represent were ubiquitously distributed along the topoedaphic gradient, but with varying abundances. Overstory-understory comparisons suggest that while future species composition of these woody communities is likely to change, PFT composition is not. Canonical correspondence analysis (CCA) ordination and variance partitioning (Partial CCA) indicated that woody species and PFT composition in developing woody communities was primarily influenced by intrinsic landscape location variables (e.g., soil texture) and secondarily by plant-induced changes in soil organic carbon and total nitrogen content. The ubiquitous distribution of species and PFTs suggests that woody plants are generally well-suited to a broad range of grassland topoedaphic settings. However, here we only examined categorical and non-quantitative functional traits. Although intrinsic soil properties exerted more control over the floristics of grassland-to-woodland succession did plant modifications of soil carbon and nitrogen concentrations, the latter

  9. Hormone Signaling Pathways in Plants: The Role of Jasmonic Acid in Plant Cell Signaling

    OpenAIRE

    TİRYAKİ, İskender

    2004-01-01

    Plant growth and metabolism are affected by various biotic and abiotic stimuli including microorganisms and insects attack as well as light and environmental stresses. Such a diverse plant response requires a communication system that uses a group of chemical messengers called hormones. Hormones promote, inhibit, or qualitatively modify plant growth and development. This complex process requires a signal transduction that defines a specific information pathway within a cell that translat...

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

    International Nuclear Information System (INIS)

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

  11. Differentiation patterns of mouse embryonic stem cells and induced pluripotent stem cells into neurons.

    Science.gov (United States)

    Nakamura, Mai; Kamishibahara, Yu; Kitazawa, Ayako; Kawaguchi, Hideo; Shimizu, Norio

    2016-05-01

    Mouse embryonic stem (ES) cells and induced pluripotent stem (iPS) cells have the ability to differentiate in vitro into various cell lineages including neurons. The differentiation of these cells into neurons has potential applications in regenerative medicine. Previously, we reported that a chick dorsal root ganglion (DRG)-conditioned medium (CM) promoted the differentiation of mouse ES and iPS cells into neurons. Here, we used real-time PCR to investigate the differentiation patterns of ES and iPS cells into neurons when DRG-CM was added. DRG-CM promoted the expression levels of βIII-tubulin gene (a marker of postmitotic neurons) in ES and iPS cells. ES cells differentiated into neurons faster than iPS cells, and the maximum peaks of gene expression involved in motor, sensory, and dopaminergic neurons were different. Rho kinase (ROCK) inhibitors could be very valuable at numerous stages in the production and use of stem cells in basic research and eventual cell-based therapies. Thus, we investigated whether the addition of a ROCK inhibitor Y-27632 and DRG-CM on the basis of the differentiation patterns promotes the neuronal differentiation of ES cells. When the ROCK inhibitor was added to the culture medium at the initial stages of cultivation, it stimulated the neuronal differentiation of ES cells more strongly than that stimulated by DRG-CM. Moreover, the combination of the ROCK inhibitor and DRG-CM promoted the neuronal differentiation of ES cells when the ROCK inhibitor was added to the culture medium at day 3. The ROCK inhibitor may be useful for promoting neuronal differentiation of ES cells. PMID:25354731

  12. How to let go: pectin and plant cell adhesion

    OpenAIRE

    Daher, Firas Bou; Braybrook, Siobhan A.

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell’s life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such...

  13. Programmed cell death in plants: A chloroplastic connection

    OpenAIRE

    Ambastha, Vivek; Tripathy, Baishnab C; Tiwari, Budhi Sagar

    2015-01-01

    Programmed cell death (PCD) is an integral cellular program by which targeted cells culminate to demise under certain developmental and pathological conditions. It is essential for controlling cell number, removing unwanted diseased or damaged cells and maintaining the cellular homeostasis. The details of PCD process has been very well elucidated and characterized in animals but similar understanding of the process in plants has not been achieved rather the field is still in its infancy that ...

  14. Morphological classification of plant cell deaths

    DEFF Research Database (Denmark)

    van Doorn, W.G.; Beers, E.P.; Dangl, J.L.;

    2011-01-01

    cell contents are removed by a combination of autophagy-like process and release of hydrolases from collapsed lytic vacuoles. Necrosis is characterised by early rupture of the plasma membrane, shrinkage of the protoplast and absence of vacuolar cell death features. Vacuolar cell death is common during...

  15. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-17

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

  16. Lateral inhibition-induced pattern formation controlled by the size and geometry of the cell.

    Science.gov (United States)

    Seirin Lee, Sungrim

    2016-09-01

    Pattern formation in development biology is one of the fundamental processes by which cells change their functions. It is based on the communication of cells via intra- and intercellular dynamics of biochemicals. Thus, the cell is directly involved in biochemical interactions. However, many theoretical approaches describing biochemical pattern formation have usually neglected the cell's role or have simplified the subcellular process without considering cellular aspects despite the cell being the environment where biochemicals interact. On the other hand, recent experimental observations suggest that a change in the physical conditions of cell-to-cell contact can result in a change in cell fate and tissue patterning in a lateral inhibition system. Here we develop a mathematical model by which biochemical dynamics can be directly observed with explicitly expressed cell structure and geometry in higher dimensions, and reconsider pattern formation by lateral inhibition of the Notch-Delta signaling pathway. We explore how the physical characteristic of cell, such as cell geometry or size, influences the biochemical pattern formation in a multi-cellular system. Our results suggest that a property based on cell geometry can be a novel mechanism for symmetry breaking inducing cell asymmetry. We show that cell volume can critically influence cell fate determination and pattern formation at the tissue level, and the surface area of the cell-to-cell contact can directly affect the spatial range of patterning. PMID:27229622

  17. Calpain-Mediated Positional Information Directs Cell Wall Orientation to Sustain Plant Stem Cell Activity, Growth and Development.

    Science.gov (United States)

    Liang, Zhe; Brown, Roy C; Fletcher, Jennifer C; Opsahl-Sorteberg, Hilde-Gunn

    2015-09-01

    Eukaryotic development and stem cell control depend on the integration of cell positional sensing with cell cycle control and cell wall positioning, yet few factors that directly link these events are known. The DEFECTIVE KERNEL1 (DEK1) gene encoding the unique plant calpain protein is fundamental for development and growth, being essential to confer and maintain epidermal cell identity that allows development beyond the globular embryo stage. We show that DEK1 expression is highest in the actively dividing cells of seeds, meristems and vasculature. We further show that eliminating Arabidopsis DEK1 function leads to changes in developmental cues from the first zygotic division onward, altered microtubule patterns and misshapen cells, resulting in early embryo abortion. Expression of the embryonic marker genes WOX2, ATML1, PIN4, WUS and STM, related to axis organization, cell identity and meristem functions, is also altered in dek1 embryos. By monitoring cell layer-specific DEK1 down-regulation, we show that L1- and 35S-induced down-regulation mainly affects stem cell functions, causing severe shoot apical meristem phenotypes. These results are consistent with a requirement for DEK1 to direct layer-specific cellular activities and set downstream developmental cues. Our data suggest that DEK1 may anchor cell wall positions and control cell division and differentiation, thereby balancing the plant's requirement to maintain totipotent stem cell reservoirs while simultaneously directing growth and organ formation. A role for DEK1 in regulating microtubule-orchestrated cell wall orientation during cell division can explain its effects on embryonic development, and suggests a more general function for calpains in microtubule organization in eukaryotic cells. PMID:26220906

  18. The Untapped Potential Of Plant Thin Cell Layers

    Directory of Open Access Journals (Sweden)

    Teixeira da Silva Jaime

    2015-12-01

    Full Text Available Thin cell layers (TCLs, which contain a small number of cells or tissues, are explants excised from different organs (stems, leaves, roots, inflorescences, flowers, cotyledons, hypocotyls/epicotyls, and embryos. After almost 45 years of research, this culture system has been used for several monocotyledonous and dicotyledonous plants of commercial importance, and for model plants. The limited amount of cells in a TCL is of paramount importance because marker molecules/genes of differentiation can be easily localized in situ in the target/responsive cells. Thus, the use of TCLs has allowed, and continues to allow, for the expansion of knowledge in plant research in a practical and applied manner into the fields of tissue culture and micropropagation, cell and organ genetics, molecular biology, biochemistry, and development. Starting from a brief historical background, the actual and potential uses of the TCL system are briefly reviewed.

  19. Single-cell and coupled GRN models of cell patterning in the Arabidopsis thaliana root stem cell niche

    Directory of Open Access Journals (Sweden)

    Alvarez-Buylla Elena R

    2010-10-01

    Full Text Available Abstract Background Recent experimental work has uncovered some of the genetic components required to maintain the Arabidopsis thaliana root stem cell niche (SCN and its structure. Two main pathways are involved. One pathway depends on the genes SHORTROOT and SCARECROW and the other depends on the PLETHORA genes, which have been proposed to constitute the auxin readouts. Recent evidence suggests that a regulatory circuit, composed of WOX5 and CLE40, also contributes to the SCN maintenance. Yet, we still do not understand how the niche is dynamically maintained and patterned or if the uncovered molecular components are sufficient to recover the observed gene expression configurations that characterize the cell types within the root SCN. Mathematical and computational tools have proven useful in understanding the dynamics of cell differentiation. Hence, to further explore root SCN patterning, we integrated available experimental data into dynamic Gene Regulatory Network (GRN models and addressed if these are sufficient to attain observed gene expression configurations in the root SCN in a robust and autonomous manner. Results We found that an SCN GRN model based only on experimental data did not reproduce the configurations observed within the root SCN. We developed several alternative GRN models that recover these expected stable gene configurations. Such models incorporate a few additional components and interactions in addition to those that have been uncovered. The recovered configurations are stable to perturbations, and the models are able to recover the observed gene expression profiles of almost all the mutants described so far. However, the robustness of the postulated GRNs is not as high as that of other previously studied networks. Conclusions These models are the first published approximations for a dynamic mechanism of the A. thaliana root SCN cellular pattering. Our model is useful to formally show that the data now available are not

  20. Psychophysiological patterns during cell phone text messaging: a preliminary study.

    Science.gov (United States)

    Lin, I-Mei; Peper, Erik

    2009-03-01

    This study investigated the psychophysiological patterns associated with cell phone text messaging (texting). Twelve college students who were very familiar with texting were monitored with surface electromyography (SEMG) from the shoulder (upper trapezius) and thumb (abductor pollicis brevis/opponens pollicis); blood volume pulse (BVP) from the middle finger, temperature from the index finger, and skin conductance (SC) from the palm of the non-texting hand; and respiration from the thorax and abdomen. The counter-balanced procedure consisted of a 2 min pre-baseline, 1 min receiving text messages, 2 min middle baseline, 1 min sending text messages and 2 min post-baseline. The results indicated that all subjects showed significant increases in respiration rate, heart rate, SC, and shoulder and thumb SEMG as compared to baseline measures. Eighty-three percentage of the participants reported hand and neck pain during texting, and held their breath and experienced arousal when receiving text messages. Subjectively, most subjects were unaware of their physiological changes. The study suggests that frequent triggering of these physiological patterns (freezing for stability and shallow breathing) may increase muscle discomfort symptoms. Thus, participants should be trained to inhibit these responses to prevent illness and discomfort. PMID:19199025

  1. Extracellular ATP signaling and homeostasis in plant cells

    OpenAIRE

    Sun, Jian; Zhang, Chunlan; Zhang, Xuan; Deng, Shurong; Zhao, Rui; Shen, Xin; Chen, Shaoliang

    2012-01-01

    Extracellular ATP (eATP) is now recognized as an important signaling agent in plant growth and defense response to environmental stimuli. eATP has dual functions in plant cell signaling, which is largely dependent on its concentration in the extracellular matrix (ECM). A lethal level of eATP (extremely low or high) causes cell death, whereas a moderate level of eATP benefits plant growth and development. Ecto-apyrases (Nucleoside Triphosphate-Diphosphohydrolase) help control the eATP concentr...

  2. Aequorin-based measurements of intracellular Ca2+-signatures in plant cells

    Directory of Open Access Journals (Sweden)

    Mithöfer Axel

    2002-01-01

    Full Text Available Due to the involvement of calcium as a main second messenger in the plant signaling pathway, increasing interest has been focused on the calcium signatures supposed to be involved in the patterning of the specific response associated to a given stimulus. In order to follow these signatures we described here the practical approach to use the non-invasive method based on the aequorin technology. Besides reviewing the advantages and disadvantages of this method we report on results showing the usefulness of aequorin to study the calcium response to biotic (elicitors and abiotic stimuli (osmotic shocks in various compartments of plant cells such as cytosol and nucleus.

  3. Recurrence patterns of bladder transitional cell carcinoma after radical cystectomy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun; Choi, Hyuck Jae; Kim, Mi-hyun; Cho, Kyung-Sik [Dept. of Radiology, Asan Medical Center, Univ. of Ulsan, Seoul (Korea, Republic of); E-mail: choihj@amc.seoul.kr

    2012-10-15

    Background Multidetector computed tomography (MDCT) is widely accepted as an effective imaging modality in monitoring for bladder cancer recurrence after radical cystectomy. Elucidating the pattern of bladder cancer recurrence on CT can increase the diagnostic accuracy. Purpose To evaluate the recurrence patterns of transitional cell carcinoma of the bladder and the factors associated with cancer recurrence. Material and Methods One hundred and forty-nine consecutive patients (mean age, 66.55 years; range, 32-86 years) who underwent preoperative contrast-enhanced CT and radical cystectomy were included in this study. The presence, site, and time of tumor recurrence were recorded retrospectively by two radiologists in a consensus fashion. The association of tumor recurrence and tumor factors (T stage, lymph node metastasis, nuclear grade, and tumor diameter) were also evaluated using multiple logistic regression analysis and Kaplan-Meier statistics. Results Tumor recurrence occurred in 60 patients (40.3%) with a mean time of 14 months (range, 1-64 months). The sites of recurrence included the operation site (n = 20), lymph node (n = 20), bone (n = 11), liver (n = 6), lung (n = 5), upper urinary tract (n = 4), colon (n = 3), adrenal gland (n = 2), peritoneum (n = 1), abdominal wall (n = 1), psoas muscle (n = 1), and penile skin (n = 1). Tumor recurrence was found to be associated with advanced T stage (P = 0.002) and lymph node metastasis (P < 0.001). Conclusion Transitional cell carcinomas of the bladder recur more frequently at the operation site and lymph node, and T-stage and lymph node metastasis are closely associated with tumor recurrence.

  4. Recurrence patterns of bladder transitional cell carcinoma after radical cystectomy

    International Nuclear Information System (INIS)

    Background Multidetector computed tomography (MDCT) is widely accepted as an effective imaging modality in monitoring for bladder cancer recurrence after radical cystectomy. Elucidating the pattern of bladder cancer recurrence on CT can increase the diagnostic accuracy. Purpose To evaluate the recurrence patterns of transitional cell carcinoma of the bladder and the factors associated with cancer recurrence. Material and Methods One hundred and forty-nine consecutive patients (mean age, 66.55 years; range, 32-86 years) who underwent preoperative contrast-enhanced CT and radical cystectomy were included in this study. The presence, site, and time of tumor recurrence were recorded retrospectively by two radiologists in a consensus fashion. The association of tumor recurrence and tumor factors (T stage, lymph node metastasis, nuclear grade, and tumor diameter) were also evaluated using multiple logistic regression analysis and Kaplan-Meier statistics. Results Tumor recurrence occurred in 60 patients (40.3%) with a mean time of 14 months (range, 1-64 months). The sites of recurrence included the operation site (n = 20), lymph node (n = 20), bone (n = 11), liver (n = 6), lung (n = 5), upper urinary tract (n = 4), colon (n = 3), adrenal gland (n = 2), peritoneum (n = 1), abdominal wall (n = 1), psoas muscle (n = 1), and penile skin (n = 1). Tumor recurrence was found to be associated with advanced T stage (P = 0.002) and lymph node metastasis (P < 0.001). Conclusion Transitional cell carcinomas of the bladder recur more frequently at the operation site and lymph node, and T-stage and lymph node metastasis are closely associated with tumor recurrence

  5. Plant species composition in a temperate forest: Multi-scale patterns and determinants

    Science.gov (United States)

    Gazol, Antonio; Ibáñez, Ricardo

    2010-11-01

    We examine the spatial patterns of plant species composition at different scales in a hierarchical sampling design with two surveys of contrasting scale. Additionally, environmental and spatial variables are used to explain the observed patterns. Five datasets were analyzed in this study. The first was obtained as a result of a large-scale spatial survey, in which the study site (132 ha) was divided into 102 large plots of 20 × 20 m. The remaining four datasets were obtained from a small-scale spatial survey, in which four of the former plots were also divided into 100 small plots of 2 × 2 m. Spatial patterns of plant species composition in both spatial surveys were quantified and the factors that influenced them were assessed using multi-scale pattern analysis (MSPA). Over the large-scale survey the topographic structure of the study site created a spatially structured environment, influencing species composition, and the spatial variables indicated that the environment was structured at a broad scale (relative to grain size and extent of the survey). In the small-scale survey the microenvironmental variables that influenced species composition were also spatially structured at a broad scale (relative to grain size and extent of the survey). However, the analyses point to the existence of spatial autocorrelation that seems to be structured at finer scales than the environmental heterogeneity in both study surveys. This study indicates that species composition in this temperate forest is not only determined by the environmental variables studied at either of the two spatial scales considered (large- and small-scale surveys). In both scales, the pure spatial component present in the analyses may be indicating the influence of unmeasured environmental variables and/or biotic processes on species composition patterns. However, while environmental heterogeneity has a broad-scale domain, biotic processes seem to work at finer scales, as is indicated by the spatial

  6. Retinoic acid, local cell-cell interactions, and pattern formation in vertebrate limbs.

    Science.gov (United States)

    Bryant, S V; Gardiner, D M

    1992-07-01

    Retinoic acid (RA), a derivative of vitamin A, has remarkable effects on developing and regenerating limbs. These effects include teratogenesis, arising from RA's ability to inhibit growth and pattern formation. They also include pattern duplication, arising as a result of the stimulation of additional growth and pattern formation. In this review we present evidence that the diverse effects of RA are consistent with a singular, underlying explanation. We propose that in all cases exogenously applied RA causes the positional information of pattern formation-competent cells to be reset to a value that is posterior-ventral-proximal with respect to the limb. The diversity of outcomes can be seen as a product of the mode of application of exogenous RA (global versus local) coupled with the unifying concept that growth and pattern formation in both limb development and limb regeneration are controlled by local cell-cell interactions, as formulated in the polar coordinate model. We explore the possibility that the major role of endogenous RA in limb development is in the establishment of the limb field rather than as a diffusible morphogen that specifies graded positional information across the limb as previously proposed. Finally, we interpret the results of the recent finding that RA can turn tail regenerates into limbs, as evidence that intercalary interactions may also be involved in the formation of the primary body axis. PMID:1628749

  7. Plant Cell Cultures as Source of Cosmetic Active Ingredients

    Directory of Open Access Journals (Sweden)

    Ani Barbulova

    2014-04-01

    Full Text Available The last decades witnessed a great demand of natural remedies. As a result, medicinal plants have been increasingly cultivated on a commercial scale, but the yield, the productive quality and the safety have not always been satisfactory. Plant cell cultures provide useful alternatives for the production of active ingredients for biomedical and cosmetic uses, since they represent standardized, contaminant-free and biosustainable systems, which allow the production of desired compounds on an industrial scale. Moreover, thanks to their totipotency, plant cells grown as liquid suspension cultures can be used as “biofactories” for the production of commercially interesting secondary metabolites, which are in many cases synthesized in low amounts in plant tissues and differentially distributed in the plant organs, such as roots, leaves, flowers or fruits. Although it is very widespread in the pharmaceutical industry, plant cell culture technology is not yet very common in the cosmetic field. The aim of the present review is to focus on the successful research accomplishments in the development of plant cell cultures for the production of active ingredients for cosmetic applications.

  8. The Upper Mississippi River floodscape: spatial patterns of flood inundation and associated plant community distributions

    Science.gov (United States)

    DeJager, Nathan R.; Rohweder, Jason J.; Yin, Yao; Hoy, Erin E.

    2016-01-01

    Questions How is the distribution of different plant communities associated with patterns of flood inundation across a large floodplain landscape? Location Thirty-eight thousand nine hundred and seventy hectare of floodplain, spanning 320 km of the Upper Mississippi River (UMR). Methods High-resolution elevation data (Lidar) and 30 yr of daily river stage data were integrated to produce a ‘floodscape’ map of growing season flood inundation duration. The distributions of 16 different remotely sensed plant communities were quantified along the gradient of flood duration. Results Models fitted to the cumulative frequency of occurrence of different vegetation types as a function of flood duration showed that most types exist along a continuum of flood-related occurrence. The diversity of community types was greatest at high elevations (0–10 d of flooding), where both upland and lowland community types were found, as well as at very low elevations (70–180 d of flooding), where a variety of lowland herbaceous communities were found. Intermediate elevations (20–60 d of flooding) tended to be dominated by floodplain forest and had the lowest diversity of community types. Conclusions Although variation in flood inundation is often considered to be the main driver of spatial patterns in floodplain plant communities, few studies have quantified flood–vegetation relationships at broad scales. Our results can be used to identify targets for restoration of historical hydrological regimes or better anticipate hydro-ecological effects of climate change at broad scales.

  9. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    Science.gov (United States)

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  10. Confocal imaging of ionised calcium in living plant cells.

    Science.gov (United States)

    Williams, D A; Cody, S H; Gehring, C A; Parish, R W; Harris, P J

    1990-04-01

    Laser-scanning confocal microscopy has been used in conjunction with Fluo-3, a highly fluorescent visible wavelength probe for Ca2+, to visualize Ca2(+)-dynamics in the function of living plant cells. This combination has overcome many of the problems that have limited the use of fluorescence imaging techniques in the study of the role of cations (Ca2+ and H+) in plant cell physiology and enables these processes to be studied in single cells within intact plant tissue preparations. Maize coleoptiles respond to application of ionophores and plant growth hormones with elevations in cytosolic Ca2+ that can be resolved with a high degree of spatial resolution and can be interpreted quantitatively. PMID:2113832

  11. A comparison of the rest complex binding patterns in embryonic stem cells and epiblast stem cells.

    Directory of Open Access Journals (Sweden)

    Masahide Seki

    Full Text Available We detected and characterized the binding sites of the representative Rest complex components Rest, Sin3A, and Lsd1. We compared their binding patterns in mouse embryonic stem (ES cells and epiblast stem (EpiS cells. We found few Rest sites unique to the EpiS cells. The ES-unique site features were distinct from those of the common sites, namely, the signal intensities were weaker, and the characteristic gene function categories differed. Our analyses showed that the Rest binding sites do not always overlap with the Sin3A and Lsd1 binding sites. The Sin3A binding pattern differed remarkably between the ES and EpiS cells and was accompanied by significant changes in acetylated-histone patterns in the surrounding regions. A series of transcriptome analyses in the same cell types unexpectedly showed that the putative target gene transcript levels were not dramatically different despite dynamic changes in the Rest complex binding patterns and chromatin statuses, which suggests that Rest is not the sole determinant of repression at its targets. Nevertheless, we identified putative Rest targets with explicitly enhanced transcription upon Rest knock-down in 143 and 60 common and ES-unique Rest target genes, respectively. Among such sites, several genes are involved in ES cell proliferation. In addition, we also found that long, intergenic non-coding RNAs were apparent Rest targets and shared similar features with the protein-coding target genes. Interestingly, such non-coding target genes showed less conservation through evolution than protein-coding targets. As a result of differences in the components and targets of the Rest complex, its functional roles may differ in ES and EpiS cells.

  12. Space radiation effects on plant and mammalian cells

    Science.gov (United States)

    Arena, C.; De Micco, V.; Macaeva, E.; Quintens, R.

    2014-11-01

    The study of the effects of ionizing radiation on organisms is related to different research aims. The current review emphasizes the studies on the effects of different doses of sparsely and densely ionizing radiation on living organisms, with the final purpose of highlighting specific and common effects of space radiation in mammals and plants. This topic is extremely relevant in the context of radiation protection from space environment. The response of different organisms to ionizing radiation depends on the radiation quality/dose and/or the intrinsic characteristics of the living system. Macromolecules, in particular DNA, are the critical targets of radiation, even if there is a strong difference between damages encountered by plant and mammalian cells. The differences in structure and metabolism between the two cell types are responsible for the higher resistance of the plant cell compared with its animal counterpart. In this review, we report some recent findings from studies performed in Space or on Earth, simulating space-like levels of radiation with ground-based facilities, to understand the effect of ionizing radiation on mammalian and plant cells. In particular, our attention is focused on genetic alterations and repair mechanisms in mammalian cells and on structures and mechanisms conferring radioresistance to plant cells.

  13. A Specific Transcriptome Signature for Guard Cells from the C4 Plant Gynandropsis gynandra.

    Science.gov (United States)

    Aubry, Sylvain; Aresheva, Olga; Reyna-Llorens, Ivan; Smith-Unna, Richard D; Hibberd, Julian M; Genty, Bernard

    2016-03-01

    C4 photosynthesis represents an excellent example of convergent evolution that results in the optimization of both carbon and water usage by plants. In C4 plants, a carbon-concentrating mechanism divided between bundle sheath and mesophyll cells increases photosynthetic efficiency. Compared with C3 leaves, the carbon-concentrating mechanism of C4 plants allows photosynthetic operation at lower stomatal conductance, and as a consequence, transpiration is reduced. Here, we characterize transcriptomes from guard cells in C3 Tareneya hassleriana and C4 Gynandropsis gynandra belonging to the Cleomaceae. While approximately 60% of Gene Ontology terms previously associated with guard cells from the C3 model Arabidopsis (Arabidopsis thaliana) are conserved, there is much less overlap between patterns of individual gene expression. Most ion and CO2 signaling modules appear unchanged at the transcript level in guard cells from C3 and C4 species, but major variations in transcripts associated with carbon-related pathways known to influence stomatal behavior were detected. Genes associated with C4 photosynthesis were more highly expressed in guard cells of C4 compared with C3 leaves. Furthermore, we detected two major patterns of cell-specific C4 gene expression within the C4 leaf. In the first, genes previously associated with preferential expression in the bundle sheath showed continually decreasing expression from bundle sheath to mesophyll to guard cells. In the second, expression was maximal in the mesophyll compared with both guard cells and bundle sheath. These data imply that at least two gene regulatory networks act to coordinate gene expression across the bundle sheath, mesophyll, and guard cells in the C4 leaf. PMID:26818731

  14. A Specific Transcriptome Signature for Guard Cells from the C4 Plant Gynandropsis gynandra1[OPEN

    Science.gov (United States)

    Aresheva, Olga; Reyna-Llorens, Ivan; Genty, Bernard

    2016-01-01

    C4 photosynthesis represents an excellent example of convergent evolution that results in the optimization of both carbon and water usage by plants. In C4 plants, a carbon-concentrating mechanism divided between bundle sheath and mesophyll cells increases photosynthetic efficiency. Compared with C3 leaves, the carbon-concentrating mechanism of C4 plants allows photosynthetic operation at lower stomatal conductance, and as a consequence, transpiration is reduced. Here, we characterize transcriptomes from guard cells in C3 Tareneya hassleriana and C4 Gynandropsis gynandra belonging to the Cleomaceae. While approximately 60% of Gene Ontology terms previously associated with guard cells from the C3 model Arabidopsis (Arabidopsis thaliana) are conserved, there is much less overlap between patterns of individual gene expression. Most ion and CO2 signaling modules appear unchanged at the transcript level in guard cells from C3 and C4 species, but major variations in transcripts associated with carbon-related pathways known to influence stomatal behavior were detected. Genes associated with C4 photosynthesis were more highly expressed in guard cells of C4 compared with C3 leaves. Furthermore, we detected two major patterns of cell-specific C4 gene expression within the C4 leaf. In the first, genes previously associated with preferential expression in the bundle sheath showed continually decreasing expression from bundle sheath to mesophyll to guard cells. In the second, expression was maximal in the mesophyll compared with both guard cells and bundle sheath. These data imply that at least two gene regulatory networks act to coordinate gene expression across the bundle sheath, mesophyll, and guard cells in the C4 leaf. PMID:26818731

  15. Turnover of galactans and other cell wall polysaccharides during development of flax plants

    International Nuclear Information System (INIS)

    We investigated the synthesis and turnover of cell wall polysaccharides of the flax (Linum usitatissimum L.) plant during development of the phloem fibers. One-month-old flax plants were exposed to a 40-min pulse with 14CO2 followed by 8-h, 24-h, and 1-month periods of chase with ambient CO2, and radioactivity in cell wall sugars was determined in various plant parts. The relative radioactivity of glucose in noncellulosic polysaccharides was the highest compared with all other cell wall sugars immediately after the pulse and decreased substantially during the subsequent chase. The relative radioactivities of the other cell wall sugars changed with differing rates, indicating turnover of specific polysaccharides. Notably, after 1 month of chase there was a marked decrease in the proportional mass and total radioactivity in cell wall galactose, indicating a long-term turnover of the galactans enriched in the fiber-containing tissues. The ratio of radiolabeled xylose to arabinose also increased during the chase, indicating a turnover of arabinose-containing polymers and interconversion to xylose. The pattern of label redistribution differed between organs, indicating that the cell wall turnover processes are tissue- and cell-specific

  16. Localization of muscarinic acetylcholine receptor in plant guard cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Acetylcholine (ACh), as an important neurotransmitter in animals, also plays a significant role in various kinds of physiological functions in plants. But relatively little is known about its receptors in plants. A green fluorescence BODIPY FL-labeled ABT, which is a high affinity ligand of muscarinic acetylcholine receptor (mAChR), was used to localize mAChR in plant guard cells. In Vicia faba L. and Pisum sativum L., mAChR was found both on the plasma membrane of guard cells. mAChR may also be distributed on guard cell chloroplast membrane of Vicia faba L. The evidence that mAChR localizes in the guard cells provides a new possible signal transduction pathway in ACh mediated stomata movement.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  18. Characteristic occurrence patterns of micropollutants and their removal efficiencies in industrial wastewater treatment plants.

    Science.gov (United States)

    Lee, In-Seok; Sim, Won-Jin; Kim, Chang-Won; Chang, Yoon-Seok; Oh, Jeong-Eun

    2011-02-01

    The concentrations and removal efficiencies of various kinds of micropollutants were investigated and the relationships between the input sources of industrial wastewater and occurrence patterns of each micropollutant were identified at nine on-site industrial wastewater treatment plants (WWTPs). The distribution pattern of each compound varied according to the WWTP type and several micropollutants were significantly related with specific industries: chlorinated phenols (ClPhs) with paper and metal industries, polycyclic aromatic hydrocarbons (PAHs) with petrogenic- and pyrogenic-related industries, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with the paper industry, and chlorinated benzenes (ClBzs) with dye-related industries. The activated sludge (AS) process was very efficient in the removal of ClPhs and PAHs, and the filtration process in the removal of PCDD/Fs and 1,4-dioxane. Generally, the removal efficiencies of each micropollutant varied according to the WWTP type. PMID:21140016

  19. Single-cell transcriptome analysis reveals coordinated ectopic gene expression patterns in medullary thymic epithelial cells

    Science.gov (United States)

    Brennecke, Philip; Reyes, Alejandro; Pinto, Sheena; Rattay, Kristin; Nguyen, Michelle; Küchler, Rita; Huber, Wolfgang; Kyewski, Bruno; Steinmetz, Lars M.

    2015-01-01

    Expression of tissue-restricted self-antigens (TRAs) in medullary thymic epithelial cells (mTECs) is essential for self-tolerance induction and prevents autoimmunity, with each TRA being expressed in only a few mTECs. How this process is regulated in single mTECs and coordinated at the population level, such that the varied single-cell patterns add up to faithfully represent TRAs, is poorly understood. Here we used single-cell RNA-sequencing and provide evidence for numerous recurring TRA co-expression patterns, each present in only a subset of mTECs. Co-expressed genes clustered in the genome and showed enhanced chromatin accessibility. Our findings characterize TRA expression in mTECs as a coordinated process, which might involve local re-modeling of chromatin and thus ensures a comprehensive representation of the immunological self. PMID:26237553

  20. Exploratory trend and pattern analysis of Caorso plant through the Tenda program

    International Nuclear Information System (INIS)

    The eleven years of operating experience of Caorso NPP supply a consistent and homogeneous data set of events involving safety-related systems and components. The above data, periodically transmitted to the Italian regulatory body (ENEA/DISP) by the utility (ENEL), as required by the italian rules and regulations, are collected into a computerised Data Bank (SEME). A PC software package (TENDA), which uses, as input, the codes from the SEME Data Bank, was set-up inside ENEA/DISP, with the aim to perform automatic Trend and pattern Analysis. Graphic software was also utilized for a more self-explaining presentation of the results. They are being utilized as input for subsequent studies related to other plants (e.g. PRA and living PRA as well). Plans for the utilization of the TENDA program for new plants and in the conventional area are now under consideration

  1. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    cannot really be synthesised or sequenced. The work described in this thesis is focused to a large extent on the development of a microarray-based high-throughput method for cell wall analysis known as Comprehensive microarray polymer profiling or CoMPP. The procedure uses highly specific molecular...... produced has provided new insight into cell wall evolution and biosynthesis and has contributed to the commercial development of cell wall materials. A major focus of the work has been the wide scale sampling of cell wall diversity across the plant kingdom, from unicellular algae to highly evolved......Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotides...

  2. Does plant apparency matter? Thirty years of data provide limited support but reveal clear patterns of the effects of plant chemistry on herbivores.

    Science.gov (United States)

    Smilanich, Angela M; Fincher, R Malia; Dyer, Lee A

    2016-05-01

    According to the plant-apparency hypothesis, apparent plants allocate resources to quantitative defenses that negatively affect generalist and specialist herbivores, while unapparent plants invest more in qualitative defenses that negatively affect nonadapted generalists. Although this hypothesis has provided a useful framework for understanding the evolution of plant chemical defense, there are many inconsistencies surrounding associated predictions, and it has been heavily criticized and deemed obsolete. We used a hierarchical Bayesian meta-analysis model to test whether defenses from apparent and unapparent plants differ in their effects on herbivores. We collected a total of 225 effect sizes from 158 published papers in which the effects of plant chemistry on herbivore performance were reported. As predicted by the plant-apparency hypothesis, we found a prevalence of quantitative defenses in woody plants and qualitative defenses in herbaceous plants. However, the detrimental impacts of qualitative defenses were more effective against specialists than generalists, and the effects of chemical defenses did not significantly differ between specialists and generalists for woody or herbaceous plants. A striking pattern that emerged from our data was a pervasiveness of beneficial effects of secondary metabolites on herbivore performance, especially generalists. This pattern provides evidence that herbivores are evolving effective counteradaptations to putative plant defenses. PMID:26889654

  3. Experience in performing trends and patterns analysis of nuclear power plant operational data

    International Nuclear Information System (INIS)

    The Office for Analysis and Evaluation of Operational Data (AEOD) of the U.S. Nuclear Regulatory Commission (USNRC) has conducted a formal trends and patterns program since 1982. Since that time, the methods and end products of the program have evolved through experience and changes in the environment for trends and patterns analysis, i.e., increasing regulatory emphasis on operations and balance of plant performance, emergence of performance indicators, the availability of personal computer hardware and software to perform analysis, and changes in the information reported to the USNRC. This paper discusses the technical milestones of the AEOD trends and patterns program in terms of: 1) Sources of operational data, e.g., pre- and post- 1984 Licensee Event Reports, NPRDS, 2) Data storage and retrieval, e.g., Sequence Coding and Search System (SCSS), 3) Statistical methods, e.g., contingency table analysis, 4) Types of results. The paper summarizes the major lessons learned in the process of implementing a trends and patterns program and outlines future direction

  4. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    OpenAIRE

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There is currently a growing interest in research on the use of PyOM as a soil amendment, inspired by the existence of highly fertile, PyOM-rich anthropogenic soils in the Amazon basin. The presence of PyOM in these so-called Amazonian Dark Earths (ADE) ...

  5. Degradation of TNT by plant cell cultures

    Czech Academy of Sciences Publication Activity Database

    Podlipná, Radka; Nepovím, Aleš; Zeman, S.; Vágner, Martin; Vaněk, Tomáš

    Praha : Faculty of Sciences Charles University, 2001. s. 31-32. [Plant Physiology Days of Young Scientists 2001. 10.07.2001-11.07.2001, Praha] R&D Projects: GA ČR GA206/99/P034; GA ČR GA206/99/1252; GA MŠk OC 837.10 Institutional research plan: CEZ:AV0Z4055905 Subject RIV: CE - Biochemistry

  6. Advanced coal gasifier-fuel cell power plant systems design

    Science.gov (United States)

    Heller, M. E.

    1983-01-01

    Two advanced, high efficiency coal-fired power plants were designed, one utilizing a phosphoric acid fuel cell and one utilizing a molten carbonate fuel cell. Both incorporate a TRW Catalytic Hydrogen Process gasifier and regenerator. Both plants operate without an oxygen plant and without requiring water feed; they, instead, require makeup dolomite. Neither plant requires a shift converter; neither plant has heat exchangers operating above 1250 F. Both plants have attractive efficiencies and costs. While the molten carbonate version has a higher (52%) efficiency than the phosphoric acid version (48%), it also has a higher ($0.078/kWh versus $0.072/kWh) ten-year levelized cost of electricity. The phosphoric acid fuel cell power plant is probably feasible to build in the near term: questions about the TRW process need to be answered experimentally, such as weather it can operate on caking coals, and how effective the catalyzed carbon-dioxide acceptor will be at pilot scale, both in removing carbon dioxide and in removing sulfur from the gasifier.

  7. Polyphosphoinositides are present in plant tissue culture cells

    International Nuclear Information System (INIS)

    Polyphosphoinositides have been isolated from wild carrot cells grown in suspension culture. This is the first report of polyphosphoinositides in plant cells. The phospholipids were identified by comigration with known standards on thin-layer plates. After overnight labeling of the cells with myo-[2-3H] inositol, the phosphoinositides as percent recovered inositol were 93% phosphatidylinositol., 3.7% lysophosphatidylinositol, 1.7% phosphatidylinositol monophosphate, 0.8% phosphatidylinositol bisphosphate

  8. Prospects for advanced coal-fuelled fuel cell power plants

    International Nuclear Information System (INIS)

    As part of ECN's in-house R and D programmes on clean energy conversion systems with high efficiencies and low emissions, system assessment studies have been carried out on coal gasification power plants integrated with high-temperature fuel cells (IGFC). The studies also included the potential to reduce CO2 emissions, and to find possible ways for CO2 extraction and sequestration. The development of this new type of clean coal technology for large-scale power generation is still far off. A significant market share is not envisaged before the year 2015. To assess the future market potential of coal-fuelled fuel cell power plants, the promise of this fuel cell technology was assessed against the performance and the development of current state-of-the-art large-scale power generation systems, namely the pulverized coal-fired power plants and the integrated coal gasification combined cycle (IGCC) power plants. With the anticipated progress in gas turbine and gas clean-up technology, coal-fuelled fuel cell power plants will have to face severe competition from advanced IGCC power plants, despite their higher efficiency. (orig.)

  9. A quantitative and dynamic model for plant stem cell regulation.

    Directory of Open Access Journals (Sweden)

    Florian Geier

    Full Text Available Plants maintain pools of totipotent stem cells throughout their entire life. These stem cells are embedded within specialized tissues called meristems, which form the growing points of the organism. The shoot apical meristem of the reference plant Arabidopsis thaliana is subdivided into several distinct domains, which execute diverse biological functions, such as tissue organization, cell-proliferation and differentiation. The number of cells required for growth and organ formation changes over the course of a plants life, while the structure of the meristem remains remarkably constant. Thus, regulatory systems must be in place, which allow for an adaptation of cell proliferation within the shoot apical meristem, while maintaining the organization at the tissue level. To advance our understanding of this dynamic tissue behavior, we measured domain sizes as well as cell division rates of the shoot apical meristem under various environmental conditions, which cause adaptations in meristem size. Based on our results we developed a mathematical model to explain the observed changes by a cell pool size dependent regulation of cell proliferation and differentiation, which is able to correctly predict CLV3 and WUS over-expression phenotypes. While the model shows stem cell homeostasis under constant growth conditions, it predicts a variation in stem cell number under changing conditions. Consistent with our experimental data this behavior is correlated with variations in cell proliferation. Therefore, we investigate different signaling mechanisms, which could stabilize stem cell number despite variations in cell proliferation. Our results shed light onto the dynamic constraints of stem cell pool maintenance in the shoot apical meristem of Arabidopsis in different environmental conditions and developmental states.

  10. From microgravity to osmotic conditions: mechanical integration of plant cells in response to stress

    Science.gov (United States)

    Wojtaszek, Przemyslaw; Kasprowicz, Anna; Michalak, Michal; Janczara, Renata; Volkmann, Dieter; Baluska, Frantisek

    Chemical reactions and interactions between molecules are commonly thought of as being at the basis of Life. Research of recent years, however, is more and more evidently indicating that physical forces are profoundly affecting the functioning of life at all levels of its organiza-tion. To detect and to respond to such forces, plant cells need to be integrated mechanically. Cell walls are the outermost functional zone of plant cells. They surround the individual cells, and also form a part of the apoplast. In cell suspensions, cell walls are embedded in the cul-ture medium which can be considered as a superapoplast. Through physical and chemical interactions they provide a basis for the structural and functional cell wall-plasma membrane-cytoskeleton (WMC) continuum spanning the whole cell. Here, the working of WMC contin-uum, and the participation of signalling molecules, like NO, would be presented in the context of plant responses to stress. In addition, the effects of the changing composition of WMC continuum will be considered, with particular attention paid to the modifications of the WMC components. Plant cells are normally adapted to changing osmotic conditions, resulting from variable wa-ter availability. The appearance of the osmotic stress activates adaptory mechanisms. If the strength of osmotic stress grows relatively slowly over longer period of time, the cells are able to adapt to conditions that are lethal to non-adapted cells. During stepwise adaptation of tobacco BY-2 suspension cells to the presence of various osmotically active agents, cells diverged into independent, osmoticum type-specific lines. In response to ionic agents (NaCl, KCl), the adhe-sive properties were increased and randomly dividing cells formed clumps, while cells adapted to nonionic osmotica (mannitol, sorbitol, PEG) revealed ordered pattern of precisely positioned cell divisions, resulting in the formation of long cell files. Changes in the growth patterns were accompanied by

  11. The market for utility-scale fuel cell plants

    Science.gov (United States)

    Watanabe, Yasuo; Matsumoto, Masaru; Takasu, Kazuhiko

    This paper is devoted to a survey of the current technology and future market for utility-scale fuel cell plants. The phosphoric acid fuel cell (PAFC) is entering into the stage where it is practically available for use with natural gas. Large capacity plants such as 11, 5 and 1 MW have been installed and operated in Italy and Japan. Their efficiency ranges from 36 to 42%. The molten carbonate fuel cell (MCFC) is in the demonstrating stage, both the fuel cell and the balance-of-plant (BOP) for natural gas. Demonstration plants of 2 and 1 MW have been under construction in the USA and Japan. Their efficiency will range from 40 to 50%. The solid oxide fuel cell (SOFC) is in the experimental stage around 100 kW for co-generation. Its conceptual system design has been conducted for both centralized and dispersed power plant in a cooperation with Westinghouse and NEDO. A market survey is now considered on the basis that future fuel cells will run for around 40 000 h in a stable manner with competitive performance. The market for fuel cells will be roughly at 2000 MW in Japan by the year 2010. Half of them will be installed for electric companies on the utility scale. The market will be shared between PAFC and MCFC by 10 and 90%, respectively. Current technologies have not reached the stage to precisely forecast when fuel cells will be entering into the market on a utility scale. At the present time, it is worthwhile to consider how the technological and economic requirements will be definitely achieved. After achieving these requirements, fuel cells will be positively introduced and socially accepted as the best energy converting option to save energy and environmental impact. Further efforts will be devoted to meeting the market from the technological and economic aspects.

  12. Glioblastoma recurrence patterns near neural stem cell regions

    Science.gov (United States)

    Chen, Linda; Chaichana, Kaisorn L.; Kleinberg, Lawrence; Ye, Xiaobu; Quinones-Hinojosa, Alfredo; Redmond, Kristin

    2016-01-01

    Purpose Glioblastoma (GBM) cancer stem cells and their neural stem cell counterparts are hypothesized to contribute to tumor progression. We examined whether GBM contrast enhancement contact with neurogenic regions (NR) affect recurrence patterns, as contrast enhancement reflects regions of blood–brain barrier breakdown. Methods 102 patients with primary GBM, treated at Johns Hopkins Hospital between 2006 and 2009, were included. All patients underwent surgical resection followed by adjuvant IMRT (60 Gy/30 fractions) and concomitant temozolomide. Initial and recurrent tumor distance from the subventricular zone (SVZ) or subgranular zone (SGZ) was measured. Tumors were categorized as NR contacting or non-contacting. The chi-square test was used to analyze the association between tumor contact and recurrence pattern. Results 49 of 102 (48.0%, 95% CI: 0.386–0.576) tumors contacted NRs at initial presentation, and, of these tumors, 49/49 (100%) contacted NRs at recurrence. Of 53 tumors that were initially non-contacting, 37/53 (69.8%, 95% CI: 0.565–0.804) recurred contacting NRs. In total, 86/102 (84.3%, 95% CI: 0.760–0.901) recurrent GBM contacted NRs compared with 49/102 (48%, 95% CI: 0.386–0.576) at initial presentation. Of the recurrent tumors that did not contact NRs, 16/53 (30.1%, 95% CI: 0.195–0.435) recurred medially toward NRs with a significant decrease in distance between tumor contrast enhancement and NRs. 16/49 (32.6%, 95% CI: 0.212–0.466) initially NR-contacting GBMs recurred out-of field while 7/53 (13.2%, 95% CI: 0.0655–0.248) initially non-contacting recurred out of the radiation treatment field (p = 0.0315, Odds ratio: 3.19, 95% CI: 1.18–8.62). Conclusions GBM contrast-enhancing recurrence is significantly associated with proximity to NRs. NR-contacting initial tumors were more likely to recur out of radiation treatment fields. PMID:26276527

  13. Three-dimensional cell manipulation and patterning using dielectrophoresis via a multi-layer scaffold structure.

    Science.gov (United States)

    Chu, H K; Huan, Z; Mills, J K; Yang, J; Sun, D

    2015-02-01

    Cell manipulation is imperative to the areas of cellular biology and tissue engineering, providing them a useful tool for patterning cells into cellular patterns for different analyses and applications. This paper presents a novel approach to perform three-dimensional (3D) cell manipulation and patterning with a multi-layer engineered scaffold. This scaffold structure employed dielectrophoresis as the non-contact mechanism to manipulate cells in the 3D domain. Through establishing electric fields via this multi-layer structure, the cells in the medium became polarized and were attracted towards the interior part of the structure, forming 3D cellular patterns. Experiments were conducted to evaluate the manipulation and the patterning processes with the proposed structure. Results show that with the presence of a voltage input, this multi-layer structure was capable of manipulating different types of biological cells examined through dielectrophoresis, enabling automatic cell patterning in the time-scale of minutes. The effects of the voltage input on the resultant cellular pattern were examined and discussed. Viability test was performed after the patterning operation and the results confirmed that majority of the cells remained viable. After 7 days of culture, 3D cellular patterns were observed through SEM. The results suggest that this scaffold and its automated dielectrophoresis-based patterning mechanism can be used to construct artificial tissues for various tissue engineering applications. PMID:25501324

  14. Interactions between zebrafish pigment cells responsible for the generation of Turing patterns.

    Science.gov (United States)

    Nakamasu, Akiko; Takahashi, Go; Kanbe, Akio; Kondo, Shigeru

    2009-05-26

    The reaction-diffusion system is one of the most studied nonlinear mechanisms that generate spatially periodic structures autonomous. On the basis of many mathematical studies using computer simulations, it is assumed that animal skin patterns are the most typical examples of the Turing pattern (stationary periodic pattern produced by the reaction-diffusion system). However, the mechanism underlying pattern formation remains unknown because the molecular or cellular basis of the phenomenon has yet to be identified. In this study, we identified the interaction network between the pigment cells of zebrafish, and showed that this interaction network possesses the properties necessary to form the Turing pattern. When the pigment cells in a restricted region were killed with laser treatment, new pigment cells developed to regenerate the striped pattern. We also found that the development and survival of the cells were influenced by the positioning of the surrounding cells. When melanophores and xanthophores were located at adjacent positions, these cells excluded one another. However, melanophores required a mass of xanthophores distributed in a more distant region for both differentiation and survival. Interestingly, the local effect of these cells is opposite to that of their effects long range. This relationship satisfies the necessary conditions required for stable pattern formation in the reaction-diffusion model. Simulation calculations for the deduced network generated wild-type pigment patterns as well as other mutant patterns. Our findings here allow further investigation of Turing pattern formation within the context of cell biology. PMID:19433782

  15. Endo-b-1,4-glucanases impact plant cell wall development by influencing cellulose crystallization

    Institute of Scientific and Technical Information of China (English)

    Magdalena Glass; Sarah Barkwill; Faride Unda; Shawn D. Mansfield

    2015-01-01

    Cell walls are vital to the normal growth and development of plants as they protect the protoplast and provide rigidity to the stem. Here, two poplar and Arabidopsis orthologous endoglucanases, which have been proposed to play a role in secondary cell wall development, were examined. The class B endoglucanases, PtGH9B5 and AtGH9B5, are secreted enzymes that have a predicted glycosylphosphatidylinositol anchor, while the class C endo-glucanases, PtGH9C2 and AtGH9C2, are also predicted to be secreted but instead contain a carbohydrate-binding module. The poplar endoglucanases were expressed in Arabidopsis using both a 35S promoter and the Arabidopsis secondary cell wall-specific CesA8 promoter. Additionally, Arabidopsis t-DNA insertion lines and an RNAi construct was created to downregulate AtGH9C2 in Arabidopsis. All of the plant lines were examined for changes in cell morphology and pattern-ing, growth and development, cell wall crystallinity, microfibril angle, and proportion of cell wall carbohydrates. Misregula-tion of PtGH9B5/AtGH9B5 resulted in changes in xylose content, while misregulation of PtGH9C2/AtGH9C2 resulted in changes in crystallinity, which was inversely correlated with changes in plant height and rosette diameter. Together, these results suggest that these endoglucanases affect secondary cell wall development by contributing to the cell wall crystallization process.

  16. Cell-to-cell movement of mitochondria in plants

    OpenAIRE

    Gurdon, Csanad; Svab, Zora; Feng, Yaping; Kumar, Dibyendu; Maliga, Pal

    2016-01-01

    We report cell-to-cell movement of mitochondria through a graft junction of two tobacco species, Nicotiana tabacum and Nicotiana sylvestris. The flowers of the N. tabacum line we used are male sterile due to a sterility-causing mitochondrial genome, whereas the N. sylvestris flowers are fertile. Grafting created an opportunity for organelle movement during the healing process when cell-to-cell connections at the graft junction were restored. We recognized N. sylvestris mitochondrial DNA trans...

  17. Nanosecond electric pulses trigger actin responses in plant cells

    International Nuclear Information System (INIS)

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  18. Nanosecond electric pulses trigger actin responses in plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca [Institute for Pulsed Power and Microwave Technology (IHM), Forschungszentrum Karlsruhe GmbH, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Hohenberger, Petra [Botanical Institute I, University of Karlsruhe, Karlsruhe Institute of Technology, Kaiserstr. 2, 76128 Karlsruhe (Germany); Wegner, Lars H. [Institute for Pulsed Power and Microwave Technology (IHM), Forschungszentrum Karlsruhe GmbH, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Botanical Institute I, University of Karlsruhe, Karlsruhe Institute of Technology, Kaiserstr. 2, 76128 Karlsruhe (Germany); Frey, Wolfgang [Institute for Pulsed Power and Microwave Technology (IHM), Forschungszentrum Karlsruhe GmbH, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Nick, Peter, E-mail: peter.nick@bio.uni-karlsruhe.de [Botanical Institute I, University of Karlsruhe, Karlsruhe Institute of Technology, Kaiserstr. 2, 76128 Karlsruhe (Germany)

    2009-09-25

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  19. The Endoplasmic Reticulum: A Social Network in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Jun Chen; Caitlin Doyle; Xingyun Qi; Huanquan Zheng

    2012-01-01

    The endoplasmic reticulum (ER) is an interconnected network comprised of ribosome-studded sheets and smooth tubules.The ER plays crucial roles in the biosynthesis and transport of proteins and lipids,and in calcium (Ca2+) regulation in compartmentalized eukaryotic cells including plant cells.To support its well-segregated functions,the shape of the ER undergoes notable changes in response to both developmental cues and outside influences.In this review,we will discuss recent findings on molecular mechanisms underlying the unique morphology and dynamics of the ER,and the importance of the interconnected ER network in cell polarity.In animal and yeast cells,two family proteins,the reticulons and DP1/Yop1,are required for shaping high-curvature ER tubules,while members of the atlastin family of dynamin-like GTPases are involved in the fusion of ER tubules to make an interconnected ER network.In plant cells,recent data also indicate that the reticulons are involved in shaping ER tubules,while RHD3,a plant member of the atlastin GTPases,is required for the generation of an interconnected ER network.We will also summarize the current knowledge on how the ER interacts with other membrane-bound organelles,with a focus on how the ER and Golgi interplay in plant cells.

  20. Oral Delivery of Protein Drugs Bioencapsulated in Plant Cells.

    Science.gov (United States)

    Kwon, Kwang-Chul; Daniell, Henry

    2016-08-01

    Plants cells are now approved by the FDA for cost-effective production of protein drugs (PDs) in large-scale current Good Manufacturing Practice (cGMP) hydroponic growth facilities. In lyophilized plant cells, PDs are stable at ambient temperature for several years, maintaining their folding and efficacy. Upon oral delivery, PDs bioencapsulated in plant cells are protected in the stomach from acids and enzymes but are subsequently released into the gut lumen by microbes that digest the plant cell wall. The large mucosal area of the human intestine offers an ideal system for oral drug delivery. When tags (receptor-binding proteins or cell-penetrating peptides) are fused to PDs, they efficiently cross the intestinal epithelium and are delivered to the circulatory or immune system. Unique tags to deliver PDs to human immune or nonimmune cells have been developed recently. After crossing the epithelium, ubiquitous proteases cleave off tags at engineered sites. PDs are also delivered to the brain or retina by crossing the blood-brain or retinal barriers. This review highlights recent advances in PD delivery to treat Alzheimer's disease, diabetes, hypertension, Gaucher's or ocular diseases, as well as the development of affordable drugs by eliminating prohibitively expensive purification, cold chain and sterile delivery. PMID:27378236

  1. Strong but diverging clonality - climate relationships of different plant clades explain weak overall pattern across China

    Science.gov (United States)

    Ye, Duo; Liu, Guofang; Song, Yao-Bin; Cornwell, William K.; Dong, Ming; Cornelissen, Johannes H. C.

    2016-06-01

    The clonal strategy should be relatively important in stressful environments (i.e. of low resource availability or harsh climate), e.g. in cold habitats. However, our understanding of the distribution pattern of clonality along environmental gradients is still far from universal. The weakness and inconsistency of overall clonality-climate relationships across taxa, as reported in previous studies, may be due to different phylogenetic lineages having fundamental differences in functional traits other than clonality determining their climate response. Thus, in this study we compared the clonality-climate relationships along a latitudinal gradient within and between different lineages at several taxonomic levels, including four major angiosperm lineages (Magnoliidae, Monocotyledoneae, Superrosidae and Superasteridae), orders and families. To this aim we used a species clonality dataset for 4015 vascular plant species in 545 terrestrial communities across China. Our results revealed clear predictive patterns of clonality proportion in relation to environmental gradients for the predominant representatives of each of the taxonomic levels above, but the relationships differed in shape and strength between the 4 major angiosperm lineages, between the 12 orders and between the 12 families. These different relationships canceled out one another when all lineages at a certain taxonomic level were pooled. Our findings highlight the importance of explicitly accounting for the functional or taxonomic scale for studying variation in plant ecological strategy across environmental gradients.

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

    OpenAIRE

    Schädel, Christina

    2009-01-01

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

  3. Do cancer cells in human and meristematic cells in plant exhibit similar responses toward plant extracts with cytotoxic activities?

    Science.gov (United States)

    Khalifa, Noha S; Barakat, Hoda S; Elhallouty, Salwa; Salem, Dina

    2015-01-01

    We examined the effect of water extracts of Persea americana fruit, and of the leaves of Tabernamontana divericata, Nerium oleander and Annona cherimolia (positive control) on Vicia faba root cells. We had confirmed in our previously published data the cytotoxicity of these plant extracts on four human cancer cell lines: liver (HepG-2), lung (A549), colon (HT-29) and breast (MCF-7). Vicia faba roots were soaked in plant extracts at dilutions of 100, 1,250, 2,500, 5,000, 10,000, 20,000 ppm for 4 and 24 h. All treatments resulted in a significant reduction in the mitotic index in a dose dependant manner. Root cells treated with T. divericata, N. oleander and A. cherimolia exhibited a decrease in prophase cell percentage, increase in micronuclei and chromosomal abnormalities as concentration increased. The P. americana treatment showed the highest cytotoxic effect on cancer cells, prophase cell percentage increased linearly with the applied concentration and no micronuclei were detected. This study shows that root tip assay of beans can be used in initial screening for new plant extracts to validate their use as candidates for containing active cytotoxic agents against malignant cells. This will greatly help in exploring new plant extracts as drugs for cancer treatment. PMID:24705601

  4. Selective pattern of cancer cell accumulation and growth using UV modulating printing of hydrogels.

    Science.gov (United States)

    Yang, Wenguang; Yu, Haibo; Wei, Fanan; Li, Gongxin; Wang, Yuechao; Liu, Lianqing

    2015-12-01

    Fabrication of extracellular microenvironment for cancer cell growth in vitro is an indispensable technique to precisely control the cell spatial arrangement and proliferation for cell-behavior research. Current micropatterning methods usually require relatively complicated operations, which makes it difficult to investigate the effects of different cell growth patterns. This manuscript proposes a DMD-based projection technique to quickly pattern a poly(ethylene) glycol diacrylate (PEGDA)-based hydrogel on a common glass substrate. Using this method, we can effectively control the growth patterns of cells. Compared with these traditional methods which employ digital dynamic mask, polymerization of PEGDA solution can be used to create arbitrary shaped microstructures with high efficiency, flexibility and repeatability. The duration of UV exposure is less than 10 s through controlling the projected illumination pattern. The ability of patterned PEGDA-coated film to hinder cell adhesion makes it possible to control area over which cells attach. In our experiments, we take advantage of the blank area to pattern cells, which allows cells to grow in various pre-designed shapes and sizes. And the patterning cells have a high viability after culturing for several days. Interestingly, we found that the restricted space could stiffen and strengthen the cells. These results indicate that cells and extracellular microenvironment can influence each other. PMID:26458559

  5. Synthesis and Application of Plant Cell Wall Oligogalactans

    DEFF Research Database (Denmark)

    Andersen, Mathias Christian Franch

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

  6. The role of the cell wall in plant immunity

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  7. Pattern of failure following surgical resection of renal cell carcinoma

    International Nuclear Information System (INIS)

    Purpose/objective: To identify the pattern of failure in patients with resected renal cell carcinoma (RCC). Materials and Methods: The records of 116 patients with unilateral non-metastatic RCC, who were treated with definitive surgery and referred to the Ottawa Regional Cancer Centre between 1977 and 1988, were reviewed. Distribution by stage included: T1 = 3 patients, T2 = 42 patients, T3 =71 patients. The median follow-up was 44 months, with a range of 4-267 months. Results: Loco-regional failure (LRF) developed in 8 patients, yielding a 7-year actuarial incidence of 8% for LRF, as first event. Nine patients developed local or regional recurrence + distant failure, and 58 patients had distant metastases only. Seven-year actuarial incidence of distant failure was 55%. The overall 7-year actuarial survival rate was 40%, and cause-specific survival was 45%. Conclusion: LRF was rare following nephrectomy. This data does not support the role of adjuvant radiation therapy in this disease

  8. Seasonal plant water uptake patterns in the saline southeast Everglades ecotone.

    Science.gov (United States)

    Ewe, Sharon M L; Sternberg, Leonel da S L; Childers, Daniel L

    2007-07-01

    The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to

  9. Cooccurrence patterns of plants and soil bacteria in the high-alpine subnival zone track environmental harshness

    Directory of Open Access Journals (Sweden)

    Andrew J. King

    2012-10-01

    Full Text Available Plants and soil microorganisms interact to play a central role in ecosystem functioning. To determine the potential importance of biotic interactions in shaping the distributions of these organisms in a high-alpine subnival landscape, we examine cooccurrence patterns between plant species and bulk-soil bacteria abundances. In this context, a cooccurrence relationship reflects a combination of several assembly processes: that both parties can disperse to the site, that they can survive the abiotic environmental conditions, and that interactions between the biota either facilitate survival or allow for coexistence. Across the entire landscape, 31% of the bacterial sequences in this dataset were significantly correlated to the abundance distribution of one or more plant species. These sequences fell into 14 clades, 6 of which are related to bacteria that are known to form symbioses with plants in other systems. Abundant plant species were more likely to have significant as well as stronger correlations with bacteria and these patterns were more prevalent in lower altitude sites. Conversely, correlations between plant species abundances and bacterial relative abundances were less frequent in sites near the snowline. Thus, plant-bacteria associations became more common as environmental conditions became less harsh and plants became more abundant. This pattern in cooccurrence strength and frequency across the subnival landscape suggests that plant-bacteria interactions are important for the success of life, both below- and above-ground, in an extreme environment.

  10. Phase-segregated model for plant cell culture: The effect of cell volume fraction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W. [Univ. of Adelaide, Adelaide (Australia). Dept. of Chemical Engineering]|[Tokyo Univ. (Japan)hinese Academy of Sciences, Dalian (China). Dalian Inst. of Chemical Physics; Furusaki, S. [Tokyo Univ. (Japan)] Middelberg, A. [Univ. of Adelaide, Adelaide (Australia). Dept. of Chemical Engineering

    1998-06-01

    Plant cells are characterized by low water content, so the fraction of cell volume (volume fraction) in a vessel is large compared with other cell systems, even if the cell concentrations are the same. Therefore, concentration of plant cells should preferably be expressed by the liquid volume basis rather than by the total vessel volume basis. In this paper, a new model is proposed to analyze behavior of a plant cell culture by dividing the cell suspension into the biotic- and abiotic-phases. Using this model, we analyzed the cell-growth and the alkaloid production by Catharanthus roseus. Large errors in the simulated results were observed if the phase-segregation was not considered. 12 refs., 3 figs.

  11. Mechanical Response of Single Plant Cells to Cell Poking: A Numerical Simulation Model

    Institute of Scientific and Technical Information of China (English)

    Rong Wang; Qun-Ying Jiao; De-Qiang Wei

    2006-01-01

    Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall,cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical,homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory.The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained.The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip,depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness,and numerical simulation is a powerful method for determining plant cell mechanical properties.

  12. Interactions between environment, species traits, and human uses describe patterns of plant invasions.

    Science.gov (United States)

    Thuiller, Wilfried; Richardson, David M; Rouget, Mathieu; Procheş, Serban; Wilson, John R U

    2006-07-01

    Although invasive alien species (IAS) are a major threat to biodiversity, human health, and economy, our understanding of the factors controlling their distribution and abundance is limited. Here, we determine how environmental factors, land use, life-history traits of the invaders, residence time, origin, and human usage interact to shape the spatial pattern of invasive alien plant species in South Africa. Relationships between the environmental factors and the extrinsic and intrinsic attributes of species were investigated using RLQ analysis, a multivariate method for relating a species-attribute table to an environmental table by way of a species presence/absence table. We then clustered species according to their position on the RLQ axes, and tested these groups for phylogenetic independence. The first three axes of the RLQ explained 99% of the variation and were strongly related to the species attributes. The clustering showed that, after accounting for environmental factors, the spatial pattern of IAS in South Africa was driven by human uses, life forms, and reproductive traits. The seven clusters of species strongly reflected geographical distribution, but also intrinsic species attributes and patterns of human use. Two of the clusters, centered on the genera Acacia and Opuntia, were phylogenetically non-independent. The remaining clusters comprised species of diverse taxonomic affinities, but sharing traits facilitating invasion in particular habitats. This information is useful for assessing the extent to which the potential spread of recent introductions can be predicted by considering the interaction of their biological attributes, region of origin, and human use. PMID:16922325

  13. Distribution patterns and changes of aquatic plant communities in Napahai Wetland in northwestern Yunnan Plateau,China

    Institute of Scientific and Technical Information of China (English)

    Derong XIAO; Kun TIAN; Hua YUAN; Yuming YANG; Ningyun LI; Shouguo XU

    2008-01-01

    Using GPS technology and community research methods for plant communities,we investigated the distribution patterns of aquatic plant communities in the high plateaus of the Napahai Wetlands,Yunnan,China,as well as the species changes of plant communities compared with that of 24 years ago since 2005.We found that the types and numbers of aquatic plant communities have changed.Some pollution-tolerant,nutrient-loving plant communities such as Scirpus tabernaemontani,Zizania caduciflora,Myriophyllum spicatum,and Azolla imbricata flourished,while the primary aquatic plant com-munities were reduced or even disappeared.The number of aquatic plant communities were increased from nine to 12 with the addition of two new emergent plant com-munities and one new floating-leaved plant community.The increase in emergent plant communities was signifi-cant.From east to west and from south to north,various types of plant communities were continuously distributed,including floating-leaved plant communities,emergent plant communities and submerged plant communities.The composition of the communities became more com-plicated and the number of accompanying species increased,while the percentage ratio of dominant plant species declined.In 2005,the coverage of emergent plant communities was the largest (528.42 hm2) followed by submerged plant communities (362.50 hm2) and the float-ing-leaf plant communities was the smallest (70.23 hm2).The variations in the distribution of aquatic plant com-munities in the Napahai Wetlands reflect the natural responses to the change of the wetland ecological envir-onment.This study indicates that human disturbances have led to an inward movement of the wetland shoreline,a decrease in water quality and a reduction in wetland habitat.

  14. Impacts of recent cultivation on genetic diversity pattern of a medicinal plant, Scutellaria baicalensis (Lamiaceae

    Directory of Open Access Journals (Sweden)

    Shao Ai-Juan

    2010-04-01

    Full Text Available Abstract Background Cultivation of medicinal plants is not only a means for meeting current and future demands for large volume production of plant-based drug and herbal remedies, but also a means of relieving harvest pressure on wild populations. Scutellaria baicalensis Georgi (Huang-qin or Chinese skullcap is a very important medicinal plant in China. Over the past several decades, wild resource of this species has suffered rapid declines and large-scale cultivation was initiated to meet the increasing demand for its root. However, the genetic impacts of recent cultivation on S. baicalensis have never been evaluated. In this study, the genetic diversity and genetic structure of 28 wild and 22 cultivated populations were estimated using three polymorphic chloroplast fragments. The objectives of this study are to provide baseline data for preserving genetic resource of S. baicalensis and to evaluate the genetic impacts of recent cultivation on medicinal plants, which may be instructive to future cultivation projects of traditional Chinese medicinal plants. Results Thirty-two haplotypes of S. baicalensis (HapA-Y and Hap1-7 were identified when three chloroplast spacers were combined. These haplotypes constituted a shallow gene tree without obvious clusters for cultivated populations, suggesting multiple origins of cultivated S. baicalensis. Cultivated populations (hT = 0.832 maintained comparable genetic variation with wild populations (hT = 0.888, indicating a slight genetic bottleneck due to multiple origins of cultivation. However, a substantial amount of rare alleles (10 out of 25 haplotypes within wild populations lost during the course of S. baicalensis cultivation. The genetic differentiation for cultivated group (GST = 0.220 was significantly lower than that of wild group (GST = 0.701. Isolation by distance analysis showed that the effect of geographical isolation on genetic structure was significant in wild populations (r = 0.4346, P r

  15. Spatiotemporal patterns of induced resistance and susceptibility linking diverse plant parasites.

    Science.gov (United States)

    Mouttet, Raphaëlle; Kaplan, Ian; Bearez, Philippe; Amiens-Desneux, Edwige; Desneux, Nicolas

    2013-12-01

    Induced defenses mediate interactions between parasites sharing the same host plant, but the outcomes of these interactions are challenging to predict because of spatiotemporal variation in plant responses and differences in defense pathways elicited by herbivores or pathogens. Dissecting these mediating factors necessitates an approach that encompasses a diversity of parasitic feeding styles and tracks interactions over space and time. We tested indirect plant-mediated relationships across three tomato (Solanum lycopersicum) consumers: (1) the fungal pathogen-powdery mildew, Oidium neolycopersici; (2) a sap-feeding insect-silverleaf whitefly, Bemisia tabaci; and (3) a chewing insect-the leaf miner, Tuta absoluta. Further, we evaluated insect/pathogen responses on local vs. systemic leaves and over short (1 day) vs. long (4 days) time scales. Overall, we documented: (1) a bi-directional negative effect between O. neolycopersici and B. tabaci; (2) an asymmetrical negative effect of B. tabaci on T. absoluta; and (3) an asymmetrical positive effect of T. absoluta on O. neolycopersici. Spatiotemporal patterns varied depending on the species pair (e.g., whitefly effects on leaf miner performance were highly localized to the induced leaf, whereas effects on pathogen growth were both local and systemic). These results highlight the context-dependent effects of induced defenses on a diverse community of tomato parasites. Notably, the outcomes correspond to those predicted by phytohormonal theory based on feeding guild differences with key implications for the recent European invasion by T. absoluta. PMID:23851986

  16. A pattern recognition approach based on DTW for automatic transient identification in nuclear power plants

    International Nuclear Information System (INIS)

    Highlights: • Novel transient identification method for NPPs. • Low-complexity. • Low training data requirements. • High accuracy. • Fully reproducible protocol carried out on a real benchmark. - Abstract: Automatic identification of transients in nuclear power plants (NPPs) allows monitoring the fatigue damage accumulated by critical components during plant operation, and is therefore of great importance for ensuring that usage factors remain within the original design bases postulated by the plant designer. Although several schemes to address this important issue have been explored in the literature, there is still no definitive solution available. In the present work, a new method for automatic transient identification is proposed, based on the Dynamic Time Warping (DTW) algorithm, largely used in other related areas such as signature or speech recognition. The novel transient identification system is evaluated on real operational data following a rigorous pattern recognition protocol. Results show the high accuracy of the proposed approach, which is combined with other interesting features such as its low complexity and its very limited requirements of training data

  17. Plant Cell and Signaling Biology Blooms in the Wuyi Mountain

    Institute of Scientific and Technical Information of China (English)

    Jianping Hu

    2011-01-01

    @@ INTRODUCTION The Eighth International Conference on Plant Biology Fron-tiers, organized by Zhenbiao Yang, Chentao Lin, and Xing-wang Deng, was convened in the Wuyi Mountain Yeohwa Resort in Fujian, China, 23-27 September 2010.The meeting's main theme was Cells and Signals, featuring four keynote speeches, 45 plenary talks, and over 40 poster presentations that covered a wide range of topics, from dynamic cellular structures to how developmental and environmental signals control various plant processes at the juncture of cells.

  18. Gravity research on plants: use of single cell experimental models

    Directory of Open Access Journals (Sweden)

    Youssef eChebli

    2011-09-01

    Full Text Available Future space missions and implementation of permanent bases on Moon and Mars will greatly depend on the availability of ambient air and sustainable food supply. Therefore, understanding the effects of altered gravity conditions on plant metabolism and growth is vital for space missions and extra-terrestrial human existence. In this mini-review we summarize how plant cells are thought to perceive changes in magnitude and orientation of the gravity vector. The particular advantages of several single celled model systems for gravity research are explored and an overview over recent advancements and potential use of these systems is provided.

  19. An assessment of plant biointrusion at the Uranium Mill Tailings Remedial Action Project rock-covered disposal cells

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    This study is one of a number of special studies that have been conducted regarding various aspects of the Uranium Mill Tailings Remedial Action (UMTRA) Project. This special study was proposed following routine surveillance and maintenance surveys and observations reported in a special study of vegetative covers (DOE, 1988), in which plants were observed growing up through the rock erosion layer at recently completed disposal cells. Some of the plants observed were deep-rooted woody species, and questions concerning root intrusion into disposal cells and the need to control plant growth were raised. The special study discussed in this report was designed to address some of the ramifications of plant growth on disposal cells that have rock covers. The NRC has chosen rock covers over vegetative covers in the arid western United States because licenses cannot substantiate that the vegetative covers will be significantly greater than 30 percent and preferably 70 percent,'' which is the amount of vegetation required to reduce flow to a point of stability.'' The potential impacts of vegetation growing in rock covers are not addressed by the NRC (1990). The objectives, then, of this study were to determine the species of plants growing on two rock-covered disposal cells, study the rooting pattern of plants on these cells, and identify possible impacts of plant root penetration on these and other UMTRA Project rock-covered cells.

  20. An assessment of plant biointrusion at the Uranium Mill Tailings Remedial Action Project rock-covered disposal cells

    International Nuclear Information System (INIS)

    This study is one of a number of special studies that have been conducted regarding various aspects of the Uranium Mill Tailings Remedial Action (UMTRA) Project. This special study was proposed following routine surveillance and maintenance surveys and observations reported in a special study of vegetative covers (DOE, 1988), in which plants were observed growing up through the rock erosion layer at recently completed disposal cells. Some of the plants observed were deep-rooted woody species, and questions concerning root intrusion into disposal cells and the need to control plant growth were raised. The special study discussed in this report was designed to address some of the ramifications of plant growth on disposal cells that have rock covers. The NRC has chosen rock covers over vegetative covers in the arid western United States because licenses cannot substantiate that the vegetative covers ''will be significantly greater than 30 percent and preferably 70 percent,'' which is the amount of ''vegetation required to reduce flow to a point of stability.'' The potential impacts of vegetation growing in rock covers are not addressed by the NRC (1990). The objectives, then, of this study were to determine the species of plants growing on two rock-covered disposal cells, study the rooting pattern of plants on these cells, and identify possible impacts of plant root penetration on these and other UMTRA Project rock-covered cells

  1. Plastids: dynamic components of plant cell development

    Science.gov (United States)

    Guikema, J. A.; Gallegos, G. L.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The gravitropic bending of maize roots, as a response to reorientation of the root within a gravitational field, was examined for sensitivity to exogenous applications of the cytoskeletal inhibitor, cytochalasin D. Agar blocks were impregnated with this inhibitor, and were applied either to the root cap or to the zone of root cell elongation. Root growth was normal with either treatment, if the roots were not repositioned with respect to the gravitational vector. When untreated roots were placed in a horizontal position with respect to gravity, a 40 degree bending response was observed within one hour. This bending also occurred when cytochalasin D was applied at high concentrations to the zone of root cell elongation. However, when cytochalasin D above 40 micrograms/ml was applied to the root cap, roots lost the ability of directional reorientation within the gravitational field, causing a random bending.

  2. Phosphatidylinositol species of suspension cultured plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Heim, S.; Wagner, K.G.

    Suspension cultured Nicotiana tabacum and Catharanthus roseus cells were labeled with (/sup 3/H)inositol, the phospholipid fraction extracted and separated by thin layer chromatography. Three different solvent systems and reference compounds were used to assign the different /sup 3/H-labeled species by autoradiography. The ratio of (/sup 3/H)inositol incorporation into PI, PIP and PIP/sub 2/ was found to be 95:4:1; with some preparations a lyso-PI band was obtained which incorporated about a tenth of the label of the PIP band. With Catharanthus roseus cells a very faint band between PI and lyso-PI was detected which could not be assigned to a reference compound.

  3. Osteoblast-like cell response to macro- and micro-patterned carbon scaffolds obtained from the sea rush Juncus maritimus

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Alvarez, M; Pereiro, I; Serra, J; Gonzalez, P [Applied Physics Department, E. I. Industriais, Campus Lagoas-Marcosende, University of Vigo, 36310 Vigo (Pontevedra) (Spain); De Carlos, A, E-mail: miriammsd@uvigo.es, E-mail: ipereiro@uvigo.es, E-mail: jserra@uvigo.es, E-mail: adcarlos@uvigo.es, E-mail: pglez@uvigo.es [Biochemistry, Genetics and Immunology Department, Biology Faculty, Campus Lagoas-Marcosende, University of Vigo, 36310 Vigo (Pontevedra) (Spain)

    2011-08-15

    Carbon scaffolds with a directional patterned surface were obtained by pyrolysis of the sea rush Juncus maritimus. The structure of the scaffolds was investigated using scanning electron microscopy, mercury porosimetry and interferometric profilometry. X-ray diffraction and x-ray fluorescence were the techniques used for their chemical characterization. The alignment and differentiation of pre-osteoblasts (MC3T3-E1 cell line) incubated on the patterned scaffolds were evaluated by scanning electron microscopy, confocal laser scanning microscopy and by the quantification of the phosphatase alkaline activity and the osteocalcin synthesis. It was found that pyrolysis at 500 {sup 0}C preserved and even enhanced the natural macro- and micro-patterning of the plant. The results obtained for porosity and chemical composition validated these structures as viable scaffolds for tissue engineering applications. Finally, the patterned surface was confirmed to promote the oriented growth of the pre-osteoblasts MC3T3-E1, not only after short periods of incubation (hours) but also after longer ones (several weeks). The quantification of the cell differentiation markers together with the evaluation of the cell layer morphology up to 28 days of incubation confirmed the differentiation of MC3T3-E1 cells to osteoblasts.

  4. Osteoblast-like cell response to macro- and micro-patterned carbon scaffolds obtained from the sea rush Juncus maritimus

    International Nuclear Information System (INIS)

    Carbon scaffolds with a directional patterned surface were obtained by pyrolysis of the sea rush Juncus maritimus. The structure of the scaffolds was investigated using scanning electron microscopy, mercury porosimetry and interferometric profilometry. X-ray diffraction and x-ray fluorescence were the techniques used for their chemical characterization. The alignment and differentiation of pre-osteoblasts (MC3T3-E1 cell line) incubated on the patterned scaffolds were evaluated by scanning electron microscopy, confocal laser scanning microscopy and by the quantification of the phosphatase alkaline activity and the osteocalcin synthesis. It was found that pyrolysis at 500 0C preserved and even enhanced the natural macro- and micro-patterning of the plant. The results obtained for porosity and chemical composition validated these structures as viable scaffolds for tissue engineering applications. Finally, the patterned surface was confirmed to promote the oriented growth of the pre-osteoblasts MC3T3-E1, not only after short periods of incubation (hours) but also after longer ones (several weeks). The quantification of the cell differentiation markers together with the evaluation of the cell layer morphology up to 28 days of incubation confirmed the differentiation of MC3T3-E1 cells to osteoblasts.

  5. Osteoblast-like cell response to macro- and micro-patterned carbon scaffolds obtained from the sea rush Juncus maritimus.

    Science.gov (United States)

    López-Álvarez, M; Pereiro, I; Serra, J; de Carlos, A; González, P

    2011-08-01

    Carbon scaffolds with a directional patterned surface were obtained by pyrolysis of the sea rush Juncus maritimus. The structure of the scaffolds was investigated using scanning electron microscopy, mercury porosimetry and interferometric profilometry. X-ray diffraction and x-ray fluorescence were the techniques used for their chemical characterization. The alignment and differentiation of pre-osteoblasts (MC3T3-E1 cell line) incubated on the patterned scaffolds were evaluated by scanning electron microscopy, confocal laser scanning microscopy and by the quantification of the phosphatase alkaline activity and the osteocalcin synthesis. It was found that pyrolysis at 500 °C preserved and even enhanced the natural macro- and micro-patterning of the plant. The results obtained for porosity and chemical composition validated these structures as viable scaffolds for tissue engineering applications. Finally, the patterned surface was confirmed to promote the oriented growth of the pre-osteoblasts MC3T3-E1, not only after short periods of incubation (hours) but also after longer ones (several weeks). The quantification of the cell differentiation markers together with the evaluation of the cell layer morphology up to 28 days of incubation confirmed the differentiation of MC3T3-E1 cells to osteoblasts. PMID:21772087

  6. Spatial distribution patterns of wetland plants in relation to environmental gradient in the Honghe National Nature Reserve, Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Demin; LUAN Zhaoqing; GUO Xiaoyu; LOU Yanjing

    2012-01-01

    Quantifying correlation between the spatial patterns of natural wetland plants and environmental gradient gives better understanding of wetland habitats,which is the fundamental for the strategy making on the protection and restoration of natural wetlands.In this study,the spatial patterns of wetland plants and the environmental gradient of wetland habitats were assessed in the Honghe National Nature Reserve (HNNR) in Northeast China,a wetland of international importance on the Ramsar list.Biophysical parameters' values of wetland plants were obtained by field sampling methods,and wetland mapping at the community scale was completed using remote sensing techniques.Digital delineation of the surface water system,hydrological zoning and wetness index were produced by spatial analysis methods in Geographic Information System.An ecological ordination method and two clustering methods were used to quantify the relationship between the spatial distribution patterns of wetland plants and the corresponding environmental gradients.Such quantitative analyses also present the specific diversity of different types of wetland plants based on the environmental attributes of their habitats.With the support from modern geo-information techniques,the experimental results indicate how four ecotypes of wetland plants spatially transit from forest swamp,shrub wetland and meadow into marsh wetland with increasing wetness index and water table.And they also show how wetland spatial distribution patterns are controlled by an environmental gradient of wetness.Another key finding of this research work is that our results present the exact fundamental differences between marsh and non-marsh plants of 11 wetland plant communities within the core study area.Hence,this case study gives a good sample for better understanding of the complex correlation between the spatial patterns of wetland plants and their environmental attributes using advanced digital analysis methods.It is also useful to

  7. Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny

    Directory of Open Access Journals (Sweden)

    Jens eMutke

    2014-10-01

    Full Text Available The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae, the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae, and the American clade of Urtica (Urticaceae. In the tropical Andes, these often grow together, especially in (naturally or anthropogenically disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape-Huancabamba Zone (AHZ between 3–8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger towards the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500–3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translates into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is

  8. Communication Pattern analysis between MCR operators that use Extended Speech Act Coding Scheme in emergency circumstance of Nuclear Power Plant

    International Nuclear Information System (INIS)

    Emergency operation circumstance of nuclear power plant asks operators fast action as is different from normal operation, abnormal operation and the result is much serious. Therefore, correct communication of operators action is required more much. So, is trying much lest human mistake at this emergency circumstance should happen at nuclear power plant. Nuclear power plant operators must take a course of normal operation, abnormal operation, emergency operation practice training and lecture room education in simulator by periodic (minimum 2/year). There have been a lot of researches about communication of nuclear power plant operator so far and these researches gave a lot of helps in operator training and power plant operation. In this study, observed emergency operation simulator practice about ISLOCA (Interfacing System LOCA) of operators of Yonggwang NPP 1. Analyzed communication patterns comparison with communication in previous abnormality circumstance analyzing comm unication patterns of operator in this scenario circumstance

  9. The impact of arbuscular mycorrhizal fungi on plant growth following herbivory: A search for pattern

    Science.gov (United States)

    Borowicz, Victoria A.

    2013-10-01

    Arbuscular mycorrhizal (AM) fungi can facilitate nutrient uptake and increase host plant growth but also place constraints on the host's carbon budget. When plants are stressed by herbivory the net effect of the symbiosis may be altered tolerance. Individual experiments manipulating AM fungi and herbivory have demonstrated increased, decreased, and no effect on tolerance but patterns with respect to plant, herbivore, or fungus characteristics have not emerged. Meta-analysis of published results from factorial experiments was used to describe the size of the effects of herbivory and of AM fungi on host growth when factors such as cause of damage, inoculum, and host characteristics are considered, and to determine whether AM fungi alter the effects of herbivory. Also, the correlation between the effect of AM fungi on tolerance and resistance was tested with data from studies that examined insect performance. Herbivory strongly and consistently reduced shoot and root growth, especially in perennial plants and crops. AM fungi increased shoot growth of perennials but not annuals, and when insects caused damage but not when artificial defoliation was applied. Root growth was consistently greater with AM fungi. The interaction of AM fungi and herbivory, which indicates whether AM fungi alter the effects of herbivory, was variable and never significant overall but homogeneity tests indicated underlying structure. In experiments that used single species inoculum, Glomus intraradices increased, whereas Glomus mosseae reduced, effects of herbivory on shoot growth. Multispecies inocula magnified effects of herbivory on root growth whereas single species inocula ameliorated effects. The impact of AM fungi on resistance to herbivory was positively correlated with the impact on tolerance; however AM fungi reduced both tolerance and resistance in many cases. Review of these results with respect to the types of systems studied suggests directions for future investigation.

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

    Science.gov (United States)

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

    2010-07-01

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

  11. Patterns of cell proliferation and cell death in the developing retina and optic tectum of the brown trout.

    NARCIS (Netherlands)

    Candal, E.; Anadon, R.; Grip, W.J. de; Rodriguez-Moldes, I.

    2005-01-01

    We have analyzed the patterns of cell proliferation and cell death in the retina and optic tectum of the brown trout (Salmo trutta fario) throughout embryonic and postembryonic stages. Cell proliferation was detected by immunohistochemistry with an antibody against the proliferating cell nuclear ant

  12. Plant co-existence patterns and High-Arctic vegetation composition in three common plant communities in north-east Greenland

    Directory of Open Access Journals (Sweden)

    Oriol Grau

    2014-09-01

    Full Text Available Arctic regions are expected to experience substantial changes in climate in the coming decades. In order to predict potential changes of Arctic vegetation, it is important to understand the distinct role of life forms of plants and of individual species in relation to plant co-existence patterns. Our aim is to investigate if three common Arctic plant patch types dominated by contrasting life forms (by the dwarf shrubs Salix arctica or Dryas octopetala×intermedia or by mosses are related (a to the co-existence of vascular plants and species richness at patch scale and (b to the floristic composition in three distinct plant communities (Salix snowbed, Dryas heath and fell-field associated with contrasting abiotic regimes. The study was conducted at Zackenberg, in north-east Greenland. Dryas patches showed a clear negative effect on small-scale plant richness and co-existence in the fell-field. Salix and moss patches showed a similar pattern in all the plant communities, although the number of individuals growing in Salix patches was lower than in moss patches. Salix and mosses in the fell-fields hosted a high number of species in spite of the much less vegetated aspect of this harsh, upper zone. The floristic composition varied between plant communities, but it did not change substantially between patch types within each community. This study provides novel background knowledge of plant co-existence patterns at patch scale and of the structure of contrasting Arctic plant communities, which will help to better assess the potential effects of varying abiotic stress regimes on Arctic vegetation.

  13. A simple way to identify non-viable cells within living plant tissue using confocal microscopy

    OpenAIRE

    Truernit Elisabeth; Haseloff Jim

    2008-01-01

    Abstract Background Plant cell death is a normal process during plant development. Mutant plants may exhibit misregulation of this process, which can lead to severe growth defects. Simple ways of visualising cell death in living plant tissues can aid the study of plant development and physiology. Results Spectral variants of the fluorescent SYTOX dyes were tested for their usefulness for the detection of non-viable cells within plant embryos and roots using confocal laser-scanning microscopy....

  14. Plant Micrometabolomics: The Analysis of Endogenous Metabolites Present in a Plant Cell or Tissue.

    OpenAIRE

    Moco, S.I.A.; B. Schneider; Vervoort, J.J.M.

    2009-01-01

    Identification and quantification of metabolites occurring within specific cell types or single cells of plants and other organisms is of particular interest for natural product chemistry, chemical ecology, and biochemistry in general. The integration of studies at the gene, transcript, protein and metabolite levels in localized regions will provide useful information for the understanding of biology as a system. In this review, we summarize the latest developments in the analysis of metaboli...

  15. Expression of photosynthesis-related gene fusions is restricted by cell type in transgenic plants and in transfected protoplasts.

    OpenAIRE

    Harkins, K R; Jefferson, R A; Kavanagh, T A; Bevan, M W; Galbraith, D W

    1990-01-01

    We have analyzed the expression of chimeric genes in populations of protoplasts isolated from the photosynthetic and nonphotosynthetic tissues within leaves of transgenic tobacco plants and separated by fluorescence-activated cell sorting. Expression of transcriptional gene fusions controlled by promoters from photosynthesis-associated genes showed a striking dependence on cell type. These patterns of expression were preserved when the gene fusions were transfected into normal (nontransgenic)...

  16. Handbook of plant cell culture. Volume 2. Crop species

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W.R.; Evans, D.A.; Ammirato, P.V.; Yamada, Y. (eds.)

    1984-01-01

    In this volume the state-of-the-art plant cell culture techniques described in the first volume are applied to several agricultural and horticultural crops. In 21 chapters, they include maize, oats, wheat, beans, red clover and other forage legumes, asparagus, celery, cassava, sweet potato, banana, pawpaw, apple, grapes, conifers, date palm, rubber, sugarcane and tobacco. Each chapter contains (1) detailed protocols to serve as the foundation for current research, (2) a critical review of the literature, and (3) in-depth evaluations of the potential shown by plant cell culture for crop improvement. The history and economic importance of each crop are discussed. This volume also includes an essay, ''Oil from plants'', by M. Calvin.

  17. Fatty Acid and Lipid Transport in Plant Cells.

    Science.gov (United States)

    Li, Nannan; Xu, Changcheng; Li-Beisson, Yonghua; Philippar, Katrin

    2016-02-01

    Fatty acids (FAs) and lipids are essential - not only as membrane constituents but also for growth and development. In plants and algae, FAs are synthesized in plastids and to a large extent transported to the endoplasmic reticulum for modification and lipid assembly. Subsequently, lipophilic compounds are distributed within the cell, and thus are transported across most membrane systems. Membrane-intrinsic transporters and proteins for cellular FA/lipid transfer therefore represent key components for delivery and dissemination. In addition to highlighting their role in lipid homeostasis and plant performance, different transport mechanisms for land plants and green algae - in the model systems Arabidopsis thaliana, Chlamydomonas reinhardtii - are compared, thereby providing a current perspective on protein-mediated FA and lipid trafficking in photosynthetic cells. PMID:26616197

  18. Timing and Controlling Dissolution of Cell Repellent Poly(Vinyl Alcohol) Thin Films for Patterned Cell Micro-Arrays

    OpenAIRE

    Lindboe, Frederic Menard

    2014-01-01

    Recently, a novel, high-throughput, patterned cell micro-array has been developed using polydopamine and poly(vinyl alcohol) (PVA) as cell adhesive and cell repellent surfaces, respectively. The step converting the cell repellent surface to an adhesive one was shown to be toxic, so this project set out to investigate whether the cell repellent PVA surface could be dissolved instead through timed or controlled dissolution. PVA film solubility was tested in water and in cell compatible media. V...

  19. A Novel Cell Death Gene Acts to Repair Patterning Defects in Drosophila melanogaster

    OpenAIRE

    Tanaka, Kentaro M.; Takahashi, Aya; Fuse, Naoyuki; Takano-Shimizu-Kouno, Toshiyuki

    2014-01-01

    Cell death is a mechanism utilized by organisms to eliminate excess cells during development. Here, we describe a novel regulator of caspase-independent cell death, Mabiki (Mabi), that is involved in the repair of the head patterning defects caused by extra copies of bicoid in Drosophila melanogaster. Mabiki functions together with caspase-dependent cell death mechanisms to provide robustness during development.

  20. Beyond ectomycorrhizal bipartite networks: projected networks demonstrate contrasted patterns between early- and late-successional plants in Corsica.

    Directory of Open Access Journals (Sweden)

    Adrien eTaudiere

    2015-10-01

    Full Text Available The ectomycorrhizal (ECM symbiosis connects mutualistic plants and fungal species into bipartite networks. While links between one focal ECM plant and its fungal symbionts have been widely documented, systemic views of ECM networks are lacking, in particular, concerning the ability of fungal species to mediate indirect ecological interactions between ECM plant species (projected-ECM networks. We assembled a large dataset of plant-fungi associations at the species level and at the scale of Corsica using molecular data and unambiguously host-assigned records to: (i examine the correlation between the number of fungal symbionts of a plant species and the average specialization of these fungal species, (ii explore the structure of the plant-plant projected network and (iii compare plant association patterns in regard to their position along the ecological succession. Our analysis reveals no trade-off between specialization of plants and specialization of their partners and a saturation of the plant projected network. Moreover, there is a significantly lower-than-expected sharing of partners between early- and late-successional plant species, with fewer fungal partners for early-successional ones and similar average specialization of symbionts of early- and late-successional plants. Our work paves the way for ecological readings of Mediterranean landscapes that include the astonishing diversity of below-ground interactions.

  1. Beyond ectomycorrhizal bipartite networks: projected networks demonstrate contrasted patterns between early- and late-successional plants in Corsica.

    Science.gov (United States)

    Taudiere, Adrien; Munoz, François; Lesne, Annick; Monnet, Anne-Christine; Bellanger, Jean-Michel; Selosse, Marc-André; Moreau, Pierre-Arthur; Richard, Franck

    2015-01-01

    The ectomycorrhizal (ECM) symbiosis connects mutualistic plants and fungal species into bipartite networks. While links between one focal ECM plant and its fungal symbionts have been widely documented, systemic views of ECM networks are lacking, in particular, concerning the ability of fungal species to mediate indirect ecological interactions between ECM plant species (projected-ECM networks). We assembled a large dataset of plant-fungi associations at the species level and at the scale of Corsica using molecular data and unambiguously host-assigned records to: (i) examine the correlation between the number of fungal symbionts of a plant species and the average specialization of these fungal species, (ii) explore the structure of the plant-plant projected network and (iii) compare plant association patterns in regard to their position along the ecological succession. Our analysis reveals no trade-off between specialization of plants and specialization of their partners and a saturation of the plant projected network. Moreover, there is a significantly lower-than-expected sharing of partners between early- and late-successional plant species, with fewer fungal partners for early-successional ones and similar average specialization of symbionts of early- and late-successional plants. Our work paves the way for ecological readings of Mediterranean landscapes that include the astonishing diversity of below-ground interactions. PMID:26539201

  2. Cell-to-cell movement of mitochondria in plants.

    Science.gov (United States)

    Gurdon, Csanad; Svab, Zora; Feng, Yaping; Kumar, Dibyendu; Maliga, Pal

    2016-03-22

    We report cell-to-cell movement of mitochondria through a graft junction. Mitochondrial movement was discovered in an experiment designed to select for chloroplast transfer fromNicotiana sylvestrisintoNicotiana tabacumcells. The alloplasmicN. tabacumline we used carriesNicotiana undulatacytoplasmic genomes, and its flowers are male sterile due to the foreign mitochondrial genome. Thus, rare mitochondrial DNA transfer fromN. sylvestristoN. tabacumcould be recognized by restoration of fertile flower anatomy. Analyses of the mitochondrial genomes revealed extensive recombination, tentatively linking male sterility toorf293, a mitochondrial gene causing homeotic conversion of anthers into petals. Demonstrating cell-to-cell movement of mitochondria reconstructs the evolutionary process of horizontal mitochondrial DNA transfer and enables modification of the mitochondrial genome by DNA transmitted from a sexually incompatible species. Conversion of anthers into petals is a visual marker that can be useful for mitochondrial transformation. PMID:26951647

  3. Target morphology and cell memory: a model of regenerative pattern formation

    Directory of Open Access Journals (Sweden)

    Nikolai Bessonov

    2015-01-01

    Full Text Available Despite the growing body of work on molecular components required for regenerative repair, we still lack a deep understanding of the ability of some animal species to regenerate their appropriate complex anatomical structure following damage. A key question is how regenerating systems know when to stop growth and remodeling - what mechanisms implement recognition of correct morphology that signals a stop condition? In this work, we review two conceptual models of pattern regeneration that implement a kind of pattern memory. In the first one, all cells communicate with each other and keep the value of the total signal received from the other cells. If a part of the pattern is amputated, the signal distribution changes. The difference fromthe original signal distribution stimulates cell proliferation and leads to pattern regeneration, in effect implementing an error minimization process that uses signaling memory to achieve pattern correction. In the second model, we consider a more complex pattern organization with different cell types. Each tissue contains a central (coordinator cell that controls the tissue and communicates with the other central cells. Each of them keeps memory about the signals received from other central cells. The values of these signals depend on the mutual cell location, and the memory allows regeneration of the structure when it is modified. The purpose of these models is to suggest possible mechanisms of pattern regeneration operating on the basis of cell memory which are compatible with diverse molecular implementation mechanisms within specific organisms.

  4. Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

    Science.gov (United States)

    Discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly c...

  5. Quantitative Assessment of Soil Health Under Different Planting Patterns and Soil Types

    Institute of Scientific and Technical Information of China (English)

    BI Chun-Juan; CHEN Zhen-Lou; WANG Jun; ZHOU Dong

    2013-01-01

    Soil health assessment is an important step toward understanding the potential effects of agricultural practices on crop yield,quality and human health.The objectives of this study were to select a minimum data set for soil health evaluation from the physical,chemical and biological properties and environmental pollution characteristics of agricultural soil and to develop a soil health diagnosis model for determining the soil health status under different planting patterns and soil types in Chongming Island of Shanghai,China.The results showed that the majority of the farmland soils in Chongming Island were in poor soil health condition,accounting for 48.9% of the survey samples,followed by the medium healthy soil,accounting for 32.2% of the survey samples and mainly distributed in the central and mid-eastern regions of the island.The indicators of pH,total organic carbon,microbial biomass carbon and Cd exerted less influence on soil health,while the soil salinization and nitrate accumulation under a greenhouse cropping pattern and phosphate fertilizer shortage in the paddy field had limited the development of soil health.Dichlorodiphenyltrichloroethanes,hexachlorocyclohexanes and Hg contributed less to soil health index (SHI) and showed no significant difference among paddy field,greenhouse and open-air vegetable/watermelon fields.The difference of the SHI of the three soil types was significant at P=0.05.The paddy soil had the highest SHI values,followed by the gray alluvial soil,and the coastal saline soil was in a poor soil health condition,indicating a need to plant some salt-tolerant crops to effectively improve soil quality.

  6. Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

    Directory of Open Access Journals (Sweden)

    Bergstrom Gary C

    2011-02-01

    Full Text Available Abstract Background The discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for the production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly cellulolytic and is a major industrial microbial source for commercial cellulases, xylanases and other cell wall degrading enzymes. However, enzyme-prospecting research continues to identify opportunities to enhance the activity of T. reesei enzyme preparations by supplementing with enzymatic diversity from other microbes. The goal of this study was to evaluate the enzymatic potential of a broad range of plant pathogenic and non-pathogenic fungi for their ability to degrade plant biomass and isolated polysaccharides. Results Large-scale screening identified a range of hydrolytic activities among 348 unique isolates representing 156 species of plant pathogenic and non-pathogenic fungi. Hierarchical clustering was used to identify groups of species with similar hydrolytic profiles. Among moderately and highly active species, plant pathogenic species were found to be more active than non-pathogens on six of eight substrates tested, with no significant difference seen on the other two substrates. Among the pathogenic fungi, greater hydrolysis was seen when they were tested on biomass and hemicellulose derived from their host plants (commelinoid monocot or dicot. Although T. reesei has a hydrolytic profile that is highly active on cellulose and pretreated biomass, it was less active than some natural isolates of fungi when tested on xylans and untreated biomass. Conclusions Several highly active isolates of plant pathogenic fungi were identified, particularly when tested on xylans and untreated biomass. There were statistically significant preferences for biomass type reflecting the monocot or dicot host preference of the

  7. Clear cell renal cell carcinoma with hemangioblastoma-like features: A recently described pattern with unusual immunohistochemical profile

    Directory of Open Access Journals (Sweden)

    Sankalp Sancheti

    2015-01-01

    Full Text Available The diagnosis of clear cell renal cell carcinoma may sometimes pose challenges because of the presence of uncharacteristic morphology, varied immunophenotypic patterns and due to lack of molecular or genetic determinants. More often, the morphological variations can be easily overlooked in routine practice and a more common diagnosis is usually put forward. Solid, acinar and alveolar are the common patterns described in the literature. We report a recently described pattern of clear cell renal cell carcinoma which has hemangioblastoma-like morphology and an unusual immunoprofile. In our case, the tumor showed a diffuse hemangioblastoma-like pattern and diffuse positivity for Alpha-inhibin on immunohistochemistry. A thorough literature search, extensive sampling and an expanded immunohistochemistry panel revealed a clear cell renal cell carcinoma component. Presence of renal vein thrombosis and focal necrosis were other helpful features in discerning the malignant nature of tumor.

  8. Engineering controlled mammalian type O-Glycosylation in plant cells

    DEFF Research Database (Denmark)

    Yang, Zhang; Drew, Damian Paul; Jørgensen, Bodil;

    2011-01-01

    Human mucins are large heavily O-glycosylated glycoproteins (>200 kDa), which account for the majority of proteins in mucus layers that e.g. hydrate, lubricate and protect cells from proteases as well as from pathogens. O-linked mucin glycans are truncated in many cancers, yielding truncated cancer...... specific glyco-peptide epitopes, such as the Tn epitope (GalNAc sugar attached to either Serine or Threonine), which are antigenic to the immune system. In the present study, we have identified plant cells as the only eukaryotic cells without mammalian type O-glycosylation or competing (for sites) O...

  9. Cell division patterns and chromosomal segregation defects in oral cancer stem cells.

    Science.gov (United States)

    Kaseb, Hatem O; Lewis, Dale W; Saunders, William S; Gollin, Susanne M

    2016-09-01

    Oral squamous cell carcinoma (OSCC) is a serious public health problem caused primarily by smoking and alcohol consumption or human papillomavirus. The cancer stem cell (CSC) theory posits that CSCs show unique characteristics, including self-renewal and therapeutic resistance. Examining biomarkers and other features of CSCs is critical to better understanding their biology. To this end, the results show that cellular SOX2 immunostaining correlates with other CSC biomarkers in OSCC cell lines and marks the rare CSC population. To assess whether CSC division patterns are symmetrical, resulting in two CSC, or asymmetrical, leading to one CSC and one cancer cell, cell size and fluorescence intensity of mitotic cells stained with SOX2 were analyzed. Asymmetrical SOX2 distribution in ≈25% of the mitoses analyzed was detected. Chromosomal instability, some of which is caused by chromosome segregation defects (CSDs), is a feature of cancer cells that leads to altered gene copy numbers. We compare chromosomal instability (as measured by CSDs) between CSCs (SOX2+) and non-CSCs (SOX2-) from the same OSCC cell lines. CSDs were more common in non-CSCs (SOX2-) than CSCs (SOX2+) and in symmetrical CSC (SOX2+) mitotic pairs than asymmetrical CSC (SOX2+/SOX2-) mitotic pairs. CSCs showed fewer and different types of CSDs after ionizing radiation treatment than non-CSCs. Overall, these data are the first to demonstrate both symmetrical and asymmetrical cell divisions with CSDs in OSCC CSC. Further, the results suggest that CSCs may undergo altered behavior, including therapeutic resistance as a result of chromosomal instability due to chromosome segregation defects. © 2016 Wiley Periodicals, Inc. PMID:27123539

  10. Regulation of cell division in higher plants. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Thomas W.

    2000-02-29

    Research in the latter part of the grant period was divided into two parts: (1) expansion of the macromolecular tool kit for studying plant cell division; (2) experiments in which the roles played by plant cell cycle regulators were to be cast in the light of the emerging yeast and animal cell paradigm for molecular control of the mitotic cycle. The first objectives were accomplished to a very satisfactory degree. With regard to the second part of the project, we were driven to change our objectives for two reasons. First, the families of cell cycle control genes that we cloned encoded such closely related members that the prospects for success at raising distinguishing antisera against each were sufficiently dubious as to be impractical. Epitope tagging is not feasible in Pisum sativum, our experimental system, as this species is not realistically transformable. Therefore, differentiating the roles of diverse cyclins and cyclin-dependent kinases was problematic. Secondly, our procedure for generating mitotically synchronized pea root meristems for biochemical studies was far too labor intensive for the proposed experiments. We therefore shifted our objectives to identifying connections between the conserved proteins of the cell cycle engine and factors that interface it with plant physiology and development. In this, we have obtained some very exciting results.

  11. Temporal patterns of damage and decay kinetics of DNA retrieved from plant herbarium specimens.

    Science.gov (United States)

    Weiß, Clemens L; Schuenemann, Verena J; Devos, Jane; Shirsekar, Gautam; Reiter, Ella; Gould, Billie A; Stinchcombe, John R; Krause, Johannes; Burbano, Hernán A

    2016-06-01

    Herbaria archive a record of changes of worldwide plant biodiversity harbouring millions of specimens that contain DNA suitable for genome sequencing. To profit from this resource, it is fundamental to understand in detail the process of DNA degradation in herbarium specimens. We investigated patterns of DNA fragmentation and nucleotide misincorporation by analysing 86 herbarium samples spanning the last 300 years using Illumina shotgun sequencing. We found an exponential decay relationship between DNA fragmentation and time, and estimated a per nucleotide fragmentation rate of 1.66 × 10(-4) per year, which is six times faster than the rate estimated for ancient bones. Additionally, we found that strand breaks occur specially before purines, and that depurination-driven DNA breakage occurs constantly through time and can to a great extent explain decreasing fragment length over time. Similar to what has been found analysing ancient DNA from bones, we found a strong correlation between the deamination-driven accumulation of cytosine to thymine substitutions and time, which reinforces the importance of substitution patterns to authenticate the ancient/historical nature of DNA fragments. Accurate estimations of DNA degradation through time will allow informed decisions about laboratory and computational procedures to take advantage of the vast collection of worldwide herbarium specimens. PMID:27429780

  12. Inductive analysis of failure patterns and of their impact on thermohydraulic circuits of nuclear power plants

    International Nuclear Information System (INIS)

    The APACHE code (Automatic Analysis of Failures of Hydraulic and Thermohydraulic Circuits more particularly of Water) situates in an important program of computer codes development in the field of studies on reliability and safety of systems in nuclear power plants. APACHE is an automatic generation code of failure pattern and of their effects. After a presentation of the theoretical basis, the methodological principles of the theory of networks are developed. Then, the model of the code is developed: model of individual behavior of each classical model component of normal behavior and model of failure pattern with specifications. The global model of hydraulic systems and the resolution systems are then developed. More particularly, some aspects of the theory of graphs, and the algorithms developed for the automatic construction of the equation systems and especially the algorithm of the research of meshes are presented. The computer aspect of the code and the programming of the code with its limits and some specifications are described. The practical aspect of utilization is finally presented

  13. Spatial organization of multiple plant species in arid ecosystems:linking patterns and processes

    Institute of Scientific and Technical Information of China (English)

    Amit; CHAKRABORTY; B.Larry; LI

    2010-01-01

    Spatial organization of multiple plant species that appears as a non-random distribution of vegetative patches is one of the mostly observed spatial patterns in arid ecosystems. Yet understanding of ecological processes allowing this spatial pattern to emerge through interspecific interactions is still lacking. With a proposed conceptual model involving interspecific trade-offs between species competitive ability and colonization ability, we have argued that within patch abundance dynamics regulated by the mechanisms of competition are strongly influenced by the between patches colonization dynamics that are maintained via this trade-offs and it holds a positive, intraspecific occupancy-abundance relationship, in which increased patch occupancy increases species density within inhabiting patches. In a constant environment, while local abundance dynamics approach toward a stable equilibrium point, a fixed spatial arrangement of species can be retained through this coupled dynamics. However, in fluctuating environments where existence of such stable equilibriums is highly uncertain, it may involve continuous transitions from one community state to another as species re-organized themselves over space through the rapid changes in local species abundances. While some of the inhabiting patches are destroyed exogenously or endogenously, or species responses to increasing environmental fluctuations vary increasingly with time, discontinuous transitions into an abrupt, irreversible state of the community dynamics may occur, as with this effect the inherent positive relationship between occupancy and abundance of species is no longer maintained.

  14. DCB-adapted plant cells possess unique wall structure

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-05-01

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

  15. Single cell deposition and patterning with a robotic system.

    Directory of Open Access Journals (Sweden)

    Zhe Lu

    Full Text Available Integrating single-cell manipulation techniques in traditional and emerging biological culture systems is challenging. Microfabricated devices for single cell studies in particular often require cells to be spatially positioned at specific culture sites on the device surface. This paper presents a robotic micromanipulation system for pick-and-place positioning of single cells. By integrating computer vision and motion control algorithms, the system visually tracks a cell in real time and controls multiple positioning devices simultaneously to accurately pick up a single cell, transfer it to a desired substrate, and deposit it at a specified location. A traditional glass micropipette is used, and whole- and partial-cell aspiration techniques are investigated to manipulate single cells. Partially aspirating cells resulted in an operation speed of 15 seconds per cell and a 95% success rate. In contrast, the whole-cell aspiration method required 30 seconds per cell and achieved a success rate of 80%. The broad applicability of this robotic manipulation technique is demonstrated using multiple cell types on traditional substrates and on open-top microfabricated devices, without requiring modifications to device designs. Furthermore, we used this serial deposition process in conjunction with an established parallel cell manipulation technique to improve the efficiency of single cell capture from ∼80% to 100%. Using a robotic micromanipulation system to position single cells on a substrate is demonstrated as an effective stand-alone or bolstering technology for single-cell studies, eliminating some of the drawbacks associated with standard single-cell handling and manipulation techniques.

  16. Diversity and aggregation patterns of plant species in a grass community

    Directory of Open Access Journals (Sweden)

    Ran Li

    2014-09-01

    Full Text Available Both composition and aggregation patterns of species in a community are the outcome of community self-organizing. In this paper we conducted analysis on species diversity and aggregation patterns of plant species in a grass community, Zhuhai, China. According to the sampling survey, in total of 47 plant species, belonging to 16 families, were found. Compositae had 10 species (21.3%, seconded by Gramineae (9 species, 19.1%, Leguminosae (6 species, 12.8%, Cyperaceae (4 species, 8.5%, and Malvaceae (3 species, 6.4%. The results revealed that the means of aggregation indices Iδ, I and m*/m were 21.71, 15.71 and 19.89 respectively and thus individuals of most of plant species strongly followed aggregative distribution. Iwao analysis indicated that both individuals of all species and clumps of all individuals of all species followed aggregative distribution. Taylor's power law indicated that individuals of all species followed aggregative distribution and aggregation intensity strengthened as the increase of mean density. We held that the strong aggregation intensity of a species has been resulted from the strong adaptation ability to the environment, the strong interspecific competition ability and the earlier establishment of the species. Fitting goodness of the mean, I, Iδ, m*/m with probability distributions demonstrated that the mean (density, I, Iδ, and m*/m over all species followed Weibull distribution rather than normal distribution. Lophatherum gracile, Paederia scandens (Lour. Merr., Eleusine indica, and Alternanthera philoxeroides (Mart. Griseb. were mostly aggregative, and Oxalis sp., Eleocharis plantagineiformis, Vernonia cinerea (L. Less., and Sapium sebiferum (L. Roxb, were mostly uniform in the spatial distribution. Importance values (IV showed that Cynodon dactylon was the most important species, seconded by Desmodium triflorum (L. DC., Cajanus scarabaeoides (L. Benth., Paspalum scrobiculatum L., and Rhynchelytrum repens. Oxalis

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue. In essence, plant cell expansion represents the foundation of development. Most studies of plant cell expansion...

  18. Mass spectrometry assisted lithography for the patterning of cell adhesion ligands on self-assembled monolayers.

    Science.gov (United States)

    Kim, Young-Kwan; Ryoo, Soo-Ryoon; Kwack, Sul-Jin; Min, Dal-Hee

    2009-01-01

    Pattern of events: A simple and flexible method has been developed for patterning cell adhesion ligands. Locally erasing self-assembled monolayers with tri(ethyleneglycol) groups on a gold substrate by using a MALDI-TOF MS nitrogen laser and filling the exposed gold surface with an alkanethiol presenting carboxylic acid groups enables subsequent immobilization of maleimide and a cell adhesion peptide, which can then recognize cells (see scheme). PMID:19347909

  19. Cell Death-Associated Molecular-Pattern Molecules: Inflammatory Signaling and Control

    OpenAIRE

    Beatriz Sangiuliano; Nancy Marcela Pérez; Moreira, Dayson F; Belizário, José E.

    2014-01-01

    Apoptosis, necroptosis, and pyroptosis are different cellular death programs characterized in organs and tissues as consequence of microbes infection, cell stress, injury, and chemotherapeutics exposure. Dying and death cells release a variety of self-proteins and bioactive chemicals originated from cytosol, nucleus, endoplasmic reticulum, and mitochondria. These endogenous factors are named cell death-associated molecular-pattern (CDAMP), damage-associated molecular-pattern (DAMP) molecules,...

  20. Plant Cell Cancer: May Natural Phenolic Compounds Prevent Onset and Development of Plant Cell Malignancy? A Literature Review.

    Science.gov (United States)

    Rasouli, Hassan; Farzaei, Mohammad Hosein; Mansouri, Kamran; Mohammadzadeh, Sara; Khodarahmi, Reza

    2016-01-01

    Phenolic compounds (PCs) are known as a chemically diverse category of secondary and reactive metabolites which are produced in plants via the shikimate-phenylpropanoid pathways. These compounds-ubiquitous in plants-are an essential part of the human diet, and are of considerable interest due to their antioxidant properties. Phenolic compounds are essential for plant functions, because they are involved in oxidative stress reactions, defensive systems, growth, and development. A large body of cellular and animal evidence carried out in recent decades has confirmed the anticancer role of PCs. Phytohormones-especially auxins and cytokinins-are key contributors to uncontrolled growth and tumor formation. Phenolic compounds can prevent plant growth by the endogenous regulation of auxin transport and enzymatic performance, resulting in the prevention of tumorigenesis. To conclude, polyphenols can reduce plant over-growth rate and the development of tumors in plant cells by regulating phytohormones. Future mechanistic studies are necessary to reveal intracellular transcription and transduction agents associated with the preventive role of phenolics versus plant pathological malignancy cascades. PMID:27563858

  1. Membrane Targeting of P-type ATPases in Plant Cells

    International Nuclear Information System (INIS)

    How membrane proteins are targeted to specific subcellular locations is a very complex and poorly understood area of research. Our long-term goal is to use P-type ATPases (ion pumps), in a model plant system Arabidopsis, as a paradigm to understand how members of a family of closely related membrane proteins can be targeted to different subcellular locations. The research is divided into two specific aims. The first aim is focused on determining the targeting destination of all 10 ACA-type calcium pumps (Arabidopsis Calcium ATPase) in Arabidopsis. ACAs represent a plant specific-subfamily of plasma membrane-type calcium pumps. In contrast to animals, the plant homologs have been found in multiple membrane systems, including the ER (ACA2), tonoplast (ACA4) and plasma membrane (ACA8). Their high degree of similarity provides a unique opportunity to use a comparative approach to delineate the membrane specific targeting information for each pump. One hypothesis to be tested is that an endomembrane located ACA can be re-directed to the plasma membrane by including targeting information from a plasma membrane isoform, ACA8. Our approach is to engineer domain swaps between pumps and monitor the targeting of chimeric proteins in plant cells using a Green Fluorescence Protein (GFP) as a tag. The second aim is to test the hypothesis that heterologous transporters can be engineered into plants and targeted to the plasma membrane by fusing them to a plasma membrane proton pump. As a test case we are evaluating the targeting properties of fusions made between a yeast sodium/proton exchanger (Sod2) and a proton pump (AHA2). This fusion may potentially lead to a new strategy for engineering salt resistant plants. Together these aims are designed to provide fundamental insights into the biogenesis and function of plant cell membrane systems

  2. How to let go: pectin and plant cell adhesion.

    Science.gov (United States)

    Daher, Firas Bou; Braybrook, Siobhan A

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell's life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells' ability to hang on, and how it lets go. PMID:26236321

  3. A xylogalacturonan epitope is specifically associated with plant cell detachment

    DEFF Research Database (Denmark)

    Willats, William George Tycho; McCartney, L.; Steele-King, C.G.;

    2004-01-01

    A monoclonal antibody (LM8) was generated with specificity for xyloglacturonan (XGA) isolated from pea (Pisum sativum L.) testae. Characterization of the LM8 epitope indicates that it is a region of XGA that is highly substituted with xylose. Immunocytochemical analysis indicates that this epitop...... that is specifically associated with a plant cell separation process that results in complete cell detachment....... is restricted to loosely attached inner parenchyma cells at the inner face of the pea testa and does not occur in other cells of the testa. Elsewhere in the pea seedling, the LM8 epitope was found only in association with root cap cell development at the root apex. Furthermore, the LM8 epitope is...... specifically associated with root cap cells in a range of angiosperm species. In embryogenic carrot suspension cell cultures the epitope is abundant at the surface of cell walls of loosely attached cells in both induced and non-induced cultures. The LM8 epitope is the first cell wall epitope to be identified...

  4. Characterization of Local Wind Patterns around the Kori Nuclear Power Plant using Cluster Analysis and WRF meteorological modeling

    International Nuclear Information System (INIS)

    To accurately predict the atmospheric diffusion of radioactive effluent, detailed analysis of local wind patterns nearby nuclear power plants are necessary. In this study, the characteristics of typical local winds around the Kori Nuclear Power Plant (Kori NPP) were investigated using the cluster analysis and Weather Research and Forecasting (WRF) meteorological modeling. In this study, the local wind characteristics around the Kori NPP were analyzed using cluster analysis and WRF meteorological modeling. As a result of the cluster analysis, four wind patterns around the Kori NPP were selected. The model study indicated the possibility that the local winds in the target area can largely contribute to the atmospheric diffusion of radioactive effluents

  5. Enhanced conversion efficiency in nanocrystalline solar cells using optically functional patterns

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Doo; Park, Sang Jun [Department of Materials and Science Engineering, Korea University, 5-1 Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Jang, Eunseok [Photovoltaic Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Oh, Kyoung Suk [KIER-UNIST Advanced Center for Energy, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Cho, Jun-Sik, E-mail: jscho@kier.re.kr [Photovoltaic Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.kr [Department of Materials and Science Engineering, Korea University, 5-1 Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of)

    2015-07-31

    The lower conversion efficiency of nanocrystalline silicon (nc-Si:H) solar cells is a result of its lower photon absorption capability of nc-Si:H. To increase photon absorption of nc-Si:H, the Ag substrates were fabricated with optically functional patterns. Two types of patterns, with random and regular structures, were formed by direct imprint technology. Owing to these optically functional patterns, the scattering of reflected light at the surface of the patterned Ag was enhanced and the optical path became longer. Thus, a greater amount of photons was absorbed by the nc-Si:H layer. Compared to flat Ag (without a surface pattern), the light absorption value of the nc-Si:H layer with a random structure pattern was increased at wavelengths ranging from 600 to 1100 nm. In the case of the regular patterned Ag, the light absorption value of the nc-Si:H layer was higher than the flat Ag at 300 to 1100 nm. Subsequently, nc-Si:H solar cells constructed on the optically functional pattern exhibit a 15.7% higher J{sub sc} value and a 19.5% higher overall conversion efficiency, compared to an identical solar cell on flat Ag. - Highlights: • Optically functional patterns were fabricated by direct printing technique. • The light absorption of solar cells was increased by the patterned Ag substrate. • Current density of solar cells on patterned Ag increased by approximately 15.7%. • The efficiency of solar cells on patterned Ag increased by 19.5%.

  6. Enhanced conversion efficiency in nanocrystalline solar cells using optically functional patterns

    International Nuclear Information System (INIS)

    The lower conversion efficiency of nanocrystalline silicon (nc-Si:H) solar cells is a result of its lower photon absorption capability of nc-Si:H. To increase photon absorption of nc-Si:H, the Ag substrates were fabricated with optically functional patterns. Two types of patterns, with random and regular structures, were formed by direct imprint technology. Owing to these optically functional patterns, the scattering of reflected light at the surface of the patterned Ag was enhanced and the optical path became longer. Thus, a greater amount of photons was absorbed by the nc-Si:H layer. Compared to flat Ag (without a surface pattern), the light absorption value of the nc-Si:H layer with a random structure pattern was increased at wavelengths ranging from 600 to 1100 nm. In the case of the regular patterned Ag, the light absorption value of the nc-Si:H layer was higher than the flat Ag at 300 to 1100 nm. Subsequently, nc-Si:H solar cells constructed on the optically functional pattern exhibit a 15.7% higher Jsc value and a 19.5% higher overall conversion efficiency, compared to an identical solar cell on flat Ag. - Highlights: • Optically functional patterns were fabricated by direct printing technique. • The light absorption of solar cells was increased by the patterned Ag substrate. • Current density of solar cells on patterned Ag increased by approximately 15.7%. • The efficiency of solar cells on patterned Ag increased by 19.5%

  7. Distribution patterns of long-lived individuals of relict plants around Fanjingshan Mountain in China: Implications for in situ conservation

    OpenAIRE

    Liao, H. Y.(Max-Planck-Institut für Physik, Munich, Germany); Ren, M. X.

    2015-01-01

    The mountain areas in south-central China are widely recognized as refugia of relict plants during the late Neogene and Quaternary periods. In this paper, we try to explore the distribution patterns of natural habitats and to exactly locate the refugia of relict species around Fanjingshan Mountain using dendrological data of long-lived individuals (≥ 100 years old). Six typical relict plants were found around the mountain, i.e. Cyclocarya paliurus, Ginkgo biloba, Liriodendron chinense, Pinus ...

  8. ß-amylase1 mutant Arabidopsis plants show improved drought tolerance due to reduced starch breakdown in guard cells.

    Science.gov (United States)

    Prasch, Christian Maximilian; Ott, Kirsten Verena; Bauer, Hubert; Ache, Peter; Hedrich, Rainer; Sonnewald, Uwe

    2015-09-01

    In plants, drought stress is a major growth limiting factor causing cell water loss through open stomata. In this study, guard cell-specific transcripts from drought-stressed Arabidopsis plants were analysed and a down-regulation of β-amylase 1 (BAM1) was found. In previous studies, BAM1 was shown to be involved in stomatal starch degradation under ambient conditions. Impaired starch breakdown of bam1 mutant plants was accompanied by decreased stomatal opening. Here, it is shown that drought tolerance of bam1 mutant plants is improved as compared with wild-type controls. Microarray analysis of stomata-specific transcripts from bam1 mutant plants revealed a significant down-regulation of genes encoding aquaporins, auxin- and ethylene-responsive factors, and cell-wall modifying enzymes. This expression pattern suggests that reduced water uptake and limited cell wall extension are associated with the closed state of stomata of bam1 mutant plants. Together these data suggest that regulation of stomata-specific starch turnover is important for adapting stomata opening to environmental needs and its breeding manipulation may result in drought tolerant crop plants. PMID:26139825

  9. WOX5–IAA17 feedback circuit-mediated cellular auxin response is crucial for the patterning of root stem cell niches in Arabidopsis

    OpenAIRE

    Tian, Huiyu; Wabnik, Krzysztof; Niu, Tiantian; Li, Hanbing; Yu, Qianqian; Pollmann, Stephan; Vanneste, Steffen; Govaerts, Willy; Rolčík, Jakub; Geisler, Markus; Friml, Jiří; Ding, Zhaojun

    2014-01-01

    In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum that emerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxin response machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell maintenance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 (WOX5) transcription factor modulates expression of auxin biosynth...

  10. Metabolism of fluoranthene in different plant cell cultures and intact plants

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, M.; Harms, H.

    2000-05-01

    The metabolism of fluoranthene was investigated in 11 cell cultures of different plant species using a [{sup 14}C]-labeled standard. Most species metabolized less than 5% of fluoranthene to soluble metabolites and formed less than 5% nonextractable residues during the standardized 48-h test procedure. Higher metabolic rates were observed in lettuce (Lactuca sativa, 6%), wheat (Tricitum aestivum, 9%), and tomato (Lycopersicon esculentum, 15%). A special high metabolic rate of nearly 50% was determined for the rose species Paul's Scarlet. Chromatographic analysis of metabolites extracted from aseptically grown tomato plants proved that the metabolites detected in the cell cultures were also formed in the intact plants. Metabolites produced in tomato and rose cells from [{sup 14}C]-fluoranthene were conjugated with glucose, glucuronic acid, and other cell components. After acid hydrolyses, the main metabolite of both species was 1-hydroxyfluoranthene as identified by gas chromatography-mass spectrometry and high-performance liquid chromatography with diode array detection. The second metabolite formed by both species was 8-hydroxyfluoranthene. A third metabolite in tomatoes was 3-hydroxyfluoranthene.

  11. An imidazole functionalized pentameric thiophene displays different staining patterns in normal and malignant cells

    OpenAIRE

    Magnusson, Karin; Appelqvist, Hanna; Cieślar-Pobuda, Artur; Bäck, Marcus; Kågedal, Bertil; Jonasson, Jon A.; Los, Marek J.; Nilsson, K Peter R

    2015-01-01

    Molecular tools for fluorescent imaging of cells and their components are vital for understanding the function and activity of cells. Here, we report an imidazole functionalized pentameric oligothiophene, p-HTIm, that can be utilized for fluorescent imaging of cells. p-HTIm fluorescence in normal cells appeared in a peripheral punctate pattern partially co-localized with lysosomes, whereas a one-sided perinuclear Golgi associated localization of the dye was observed in malignant cells. The up...

  12. Unit-cell determination from randomly oriented electron-diffraction patterns

    International Nuclear Information System (INIS)

    An algorithm is described that calculates the most likely primitive unit cell given a set of randomly oriented electron-diffraction patterns with unknown angular relationships. Unit-cell determination is the first step towards the structure solution of an unknown crystal form. Standard procedures for unit-cell determination cannot cope with data collections that consist of single diffraction patterns of multiple crystals, each with an unknown orientation. However, for beam-sensitive nanocrystals these are often the only data that can be obtained. An algorithm for unit-cell determination that uses randomly oriented electron-diffraction patterns with unknown angular relationships is presented here. The algorithm determined the unit cells of mineral, pharmaceutical and protein nanocrystals in orthorhombic high- and low-symmetry space groups, allowing (well oriented) patterns to be indexed

  13. Protein micro patterned lattices to probe a fundamental lengthscale involved in cell adhesion

    CERN Document Server

    Guillou, Herve; Chaussy, Jacques; Block, Marc R

    2009-01-01

    Cell adhesion, a fundamental process of cell biology is involved in the embryo development and in numerous pathologies especially those related to cancers. We constrained cells to adhere on extracellular matrix proteins patterned in a micro lattices. The actin cytoskeleton is particularly sensitive to this constraint and reproducibly self organizes in simple geometrical patterns. Such highly organized cells are functional and proliferate. We performed statistical analysis of spread cells morphologies and discuss the existence of a fundamental lengthscale associated with active processes required for spreading.

  14. Controlled neuronal cell patterning and guided neurite growth on micropatterned nanofiber platforms

    International Nuclear Information System (INIS)

    Patterning neuronal cells and guiding neurite growth are important for applications such as prosthetics, cell based biosensors, and tissue engineering. In this paper, a microdevice is presented that provides neuronal cell patterning and guided neurite growth on a collagen coated gelatin/PCL nanofiber mat. The pattern consisted of a grid of polystyrene microwells/nodes to confine the cell bodies and orthogonal grooves to guide neurite growth from each node. Vacuum assisted cell seeding was used to localize cell bodies in the microwells and physically separate the cells during seeding. The electrospun nanofiber mats under the polystyrene microstructures were coated with collagen to enhance the cellular attachment and enhance differentiation. We evaluated the performance of our device using adhesion, viability, and differentiation assays of neuron-like PC12 cells compared to controls for vacuum seeding, spatial isolation and guidance, and collagen coating of the fibers. The device provided PC12 cell patterning with increased adhesion, differentiation, and guided neurite outgrowth compared to controls, demonstrating its potential for in vitro neuronal cell patterning studies. (paper)

  15. Thymoquinone causes multiple effects, including cell death, on dividing plant cells.

    Science.gov (United States)

    Hassanien, Sameh E; Ramadan, Ahmed M; Azeiz, Ahmed Z Abdel; Mohammed, Rasha A; Hassan, Sabah M; Shokry, Ahmed M; Atef, Ahmed; Kamal, Khalid B H; Rabah, Samar; Sabir, Jamal S M; Abuzinadah, Osama A; El-Domyati, Fotouh M; Martin, Gregory B; Bahieldin, Ahmed

    2013-01-01

    Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ. PMID:24296078

  16. Plant Hormones Increase Efficiency of Reprogramming Mouse Somatic Cells to Induced Pluripotent Stem Cells and Reduce Tumorigenicity

    OpenAIRE

    Alvarez Palomo, Ana Belén; McLenachan, Samuel; Requena Osete, Jordi; Menchón, Cristina; Barrot, Carme; Chen, Fred; Munné-Bosch, Sergi; Michael J. Edel

    2013-01-01

    Reprogramming of somatic cells into induced pluripotent stem (iPS) cells by defined pluripotency and self-renewal factors has taken stem cell technology to the forefront of regenerative medicine. However, a number of challenges remain in the field including efficient protocols and the threat of cancer. Reprogramming of plant somatic cells to plant embryonic stem cells using a combination of two plant hormones was discovered in 1957 and has been a routine university laboratory practical for ov...

  17. LEG ULCERS IN SICKLE CELL DISEASE: CURRENT PATTERNS AND PRACTICES

    OpenAIRE

    Delaney, Kara-Marie H.; Axelrod, Karen C.; Buscetta, Ashley; Hassell, Kathryn L.; Adams-Graves, Patricia E.; Seamon, Catherine; Kato, Gregory J.; Minniti, Caterina P.

    2013-01-01

    Leg ulcers are a debilitating complication of patients with sickle cell disease, and their frequency in North America was reported to be 2.5% by the Cooperative Study of Sickle Cell Disease more than 20 years ago. We sought to determine if the frequency of leg ulcers in sickle cell patients in the United States had declined and to assess which treatments providers use most commonly. We sent an e-mail survey to health professionals belonging to the national Sickle Cell Adult Provider Network. ...

  18. Development of Spatial Distribution Patterns by Biofilm Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Hansen, Susse Kirkelund; Bak Christensen, Bjarke;

    2015-01-01

    Confined spatial patterns of microbial distribution are prevalent in nature, such as in microbial mats, soil communities, and water stream biofilms. The symbiotic two-species consortium of Pseudomonas putida and Acinetobacter sp. C6, originally isolated from a creosote-polluted aquifer, has evolved......, as well as the ecology of engineered communities that have the potential for enhanced and sustainable bioprocessing capacity....

  19. Metal-accelerated oxidation in plant cell death

    Energy Technology Data Exchange (ETDEWEB)

    Czuba, M. (National Research Council, Ottawa, Ontario (Canada))

    1993-05-01

    Cadmium and mercury toxicity is further enhanced by external oxidizing conditions O[sub 3] or inherent plant processes. Lepidium sativum L, Lycopersicon esculentum Mill., or Phaseolus vulgaris L, were grown inpeat-lite to maturity under continuous cadmium exposure followed by one oxidant (O[sub 3]-6 hr. 30 pphm) exposure, with or without foliar calcium pretreatments. In comparison, Daucus carota, L and other species grown in a 71-V suspension, with or without 2,4-D were exposed continuously to low levels of methylmercury during exponential growth and analyzed in aggregates of distinct populations. Proteins were extracted and analyzed. Mechanisms of toxicity and eventual cell death are Ca-mediated and involve chloroplast, stomatal-water relations and changes in oxidant-anti-oxidant components in cells. Whether the metal-accelerated oxidative damage proceeds to cell death, depends on the species and its differential biotransformation system and cell association component.

  20. Integrating fuel cell power systems into building physical plants

    Energy Technology Data Exchange (ETDEWEB)

    Carson, J. [KCI Technologies, Inc., Hunt Valley, MD (United States)

    1996-12-31

    This paper discusses the integration of fuel cell power plants and absorption chillers to cogenerate chilled water or hot water/steam for all weather air conditioning as one possible approach to building system applications. Absorption chillers utilize thermal energy in an absorption based cycle to chill water. It is feasible to use waste heat from fuel cells to provide hydronic heating and cooling. Performance regimes will vary as a function of the supply and quality of waste heat. Respective performance characteristics of fuel cells, absorption chillers and air conditioning systems will define relationships between thermal and electrical load capacities for the combined systems. Specifically, this paper develops thermodynamic relationships between bulk electrical power and cooling/heating capacities for combined fuel cell and absorption chiller system in building applications.

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

    OpenAIRE

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

    2014-01-01

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

  2. Thermoelectric cells cogeneration from biomass power plant: literature review

    OpenAIRE

    Bianchini, Augusto; Donini, Filippo; Pellegrini, Marco

    2015-01-01

    Thermoelectric cells convert directly heat into electricity but, due to the low conversion efficiency (up to 5%), most applications are in waste heat recovery. Another promising application is in biomass boiler. In this case, the installation of thermoelectric modules converts a biomass boiler into a cogeneration system, where the aim of the integration is not the electricity production for external power supply, but the realization of a stand-alone biomass power plant which could match the c...

  3. Plant cell walls: New insights from ancient species

    DEFF Research Database (Denmark)

    Sørensen, Iben; Willats, William George Tycho

    2008-01-01

    ¿4)-linked ß-D-Glcp are joined by occasional (1¿3)-linkages. This mixed linkage glucan (MLG) has been the subject of extensive research because of the economic importance of several Poales species including rice, barley and wheat and because MLG has proven health benefits. The recent discovery of MLG......-D-glucan is not unique to the Poales and is an abundant component of Equisetum arvense cell walls. Plant J 2008; 54:510-21....

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

    Science.gov (United States)

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

    1992-01-01

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

  5. ERC product improvement activities for direct fuel cell power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, C.; Carlson, G.; Doyon, J. [and others

    1995-08-01

    This program is designed to advance the carbonate fuel cell technology from the current power plant demonstration status to the commercial design in an approximately five-year period. The specific objectives which will allow attainment of the overall program goal are: (1) Define market-responsive power plant requirements and specifications, (2) Establish the design for a multifuel, low-cost, modular, market-responsive power plant, (3) Resolve power plant manufacturing issues and define the design for the commercial manufacturing facility, (4) Define the stack and BOP equipment packaging arrangement and define module designs, (5) Acquire capability to support developmental testing of stacks and BOP equipment as required to prepare for commercial design, and (6) Resolve stack and BOP equipment technology issues and design, build, and field test a modular commercial prototype power plant to demonstrate readiness for commercial entry. A seven-task program, dedicated to attaining objective(s) in the areas noted above, was initiated in December 1994. Accomplishments of the first six months are discussed in this paper.

  6. Collective motion of cells mediates segregation and pattern formation in co-cultures.

    Directory of Open Access Journals (Sweden)

    Elod Méhes

    Full Text Available Pattern formation by segregation of cell types is an important process during embryonic development. We show that an experimentally yet unexplored mechanism based on collective motility of segregating cells enhances the effects of known pattern formation mechanisms such as differential adhesion, mechanochemical interactions or cell migration directed by morphogens. To study in vitro cell segregation we use time-lapse videomicroscopy and quantitative analysis of the main features of the motion of individual cells or groups. Our observations have been extensive, typically involving the investigation of the development of patterns containing up to 200,000 cells. By either comparing keratocyte types with different collective motility characteristics or increasing cells' directional persistence by the inhibition of Rac1 GTP-ase we demonstrate that enhanced collective cell motility results in faster cell segregation leading to the formation of more extensive patterns. The growth of the characteristic scale of patterns generally follows an algebraic scaling law with exponent values up to 0.74 in the presence of collective motion, compared to significantly smaller exponents in case of diffusive motion.

  7. Digitized quantitative electroencephalographic patterns applied as magnetic fields inhibit melanoma cell proliferation in culture.

    Science.gov (United States)

    Karbowski, Lukasz M; Harribance, Sean L; Buckner, Carly A; Mulligan, Bryce P; Koren, Stanley A; Lafrenie, Robert M; Persinger, Michael A

    2012-08-15

    Weak (1 μT) physiologically patterned magnetic fields produce changes in behavioral, physiological, and cellular activity. In the present experiments 12 temporal samples of the electroencephalographic anomaly and normal activity of a person (SLH) whose proximity reliably affected the brain activity of others were extracted from QEEG data, digitized, and presented as equivalent magnetic field patterns to B16 mouse melanoma cells. Only two of the patterns, both originating from the primary source (right temporal lobe) of the EEG anomaly reduced the cell growth by one-third compared to the other patterns extracted from his QEEG or sham field exposures. In previous experiments these EEG transients were also associated with marked increases in photon emissions from the right side of SLH's head. The results suggest that the intrinsic complexity of electroencephalographic patterns of some people, when amplified appropriately and applied as computer-generated magnetic fields in the three spatial planes, could diminish cancer cell growth. PMID:22750152

  8. Factors influencing the temporal and spatial patterns of dogwood borer (Lepidoptera: Sesiidae) infestations in newly planted apple orchards

    Science.gov (United States)

    The temporal and spatial patterns of infestation by larval dogwood borer, Synanthedon scitula (Harris), was studied during 2002–2004 in two newly planted apple orchards in West Virginia and Virginia. The orchards contained several rootstock-variety combinations grown under different cultural manage...

  9. On the rates and patterns of spread of alien plants in the Czech Republic, Britain and Ireland

    Czech Academy of Sciences Publication Activity Database

    Williamson, M.; Pyšek, Petr; Jarošík, Vojtěch; Prach, Karel

    2005-01-01

    Roč. 12, č. 3 (2005), s. 424-433. ISSN 1195-6860 R&D Projects: GA ČR(CZ) GA206/03/1216 Institutional research plan: CEZ:AV0Z60050516 Keywords : alien plants * rate of spread * pattern of spread Subject RIV: EF - Botanics Impact factor: 1.261, year: 2005

  10. Morphological Transformation of Plant Cells in vitro and Its Effect on Plant Growth

    Institute of Scientific and Technical Information of China (English)

    GUO Zhigang; ZENG Zhaolin; LIU Ruizhi; DENG Ying

    2005-01-01

    Enhancement of cell growth in suspension cultures is urgently needed in plant cell culture engineering. This study investigates the relationship between morphological transformation and cell growth in callus and suspension cultures of saffron cells belonging to the cell line C96 induced from Crocus sativus L. In the suspension culture, an unbalanced osmotic pressure between the intracell and extracell regions induced a large morphological transformation which affected normal division of the saffron cells. An increase in osmotic pressure caused by the addition of sucrose inhibits the vacuolation and shrinkage of cytoplasm in the cells. As the sucrose concentration increases, the total amount of accumulated biomass also increases. Besides the sucrose concentration, increased ionic strength and inoculation ratio also help restrain to a large extent the vacuolation and shrinkage of the cytoplasm in the suspended cells, which results in increased biomass. The conditions for optimal biomass are: Murashige and Skoog's (MS) medium with 40 g/L sucrose and 60% (v/v) inoculation ratio.

  11. Geographical patterns of Yunnan seed plants may be influenced by the Clockwise Rotation of the Simao-Indochina Geoblock

    Directory of Open Access Journals (Sweden)

    Zhu eHua

    2015-09-01

    Full Text Available Floristic patterns of seed plants in Yunnan, southwestern China, were studied to assess the relationship between the floristic geography and geological history. A database of 38 regional floristic studies covering Yunnan was used and the patterns of seed plant distributions across these regional floras were quantified at the generic level. Genera with tropical Asian distributions are the most dominant geographical elements in the Yunnan flora. They show oblique patterns of abundance across Yunnan. They are most abundant in southern and western Yunnan, and their proportion in regional floras declines abruptly in eastern, central and northern Yunnan. The oblique abundance patterns of geographical elements in Yunnan differ from those of genera in southern and eastern China, which had a high correlation with latitudinal gradients controlled by climate. They cannot be explained by climate alone, but can be explained at least partly by the geological history. The oblique abundance patterns of Yunnan seed plants correspond well to the clockwise rotation and southeastward extrusion of the Simao-Indochina geoblock caused by the collision of India with Asia.

  12. Geographical patterns of Yunnan seed plants may be influenced by the Clockwise Rotation of the Simao-Indochina Geoblock

    Science.gov (United States)

    Hua, Zhu

    2015-09-01

    Floristic patterns of seed plants in Yunnan, southwestern China, were studied to assess the relationship between the floristic geography and geological history. A database of 38 regional floristic studies covering Yunnan was used and the patterns of seed plant distributions across these regional floras were quantified at the generic level. Genera with tropical Asian distributions are the most dominant geographical elements in the Yunnan flora. They show oblique patterns of abundance across Yunnan. They are most abundant in southern and western Yunnan, and their proportion in regional floras declines abruptly in eastern, central and northern Yunnan. The oblique abundance patterns of geographical elements in Yunnan differ from those of genera in southern and eastern China, which had a high correlation with latitudinal gradients controlled by climate. They cannot be explained by climate alone, but can be explained at least partly by the geological history. The oblique abundance patterns of Yunnan seed plants correspond well to the clockwise rotation and southeastward extrusion of the Simao-Indochina geoblock caused by the collision of India with Asia.

  13. Native cell-death genes as candidates for developing wilt resistance in transgenic banana plants.

    Science.gov (United States)

    Ghag, Siddhesh B; Shekhawat, Upendra K Singh; Ganapathi, Thumballi R

    2014-01-01

    In order to feed an ever-increasing world population, there is an urgent need to improve the production of staple food and fruit crops. The productivity of important food and fruit crops is constrained by numerous biotic and abiotic factors. The cultivation of banana, which is an important fruit crop, is severely threatened by Fusarium wilt disease caused by infestation by an ascomycetes fungus Fusarium oxysporum f. sp. cubense (Foc). Since there are no established edible cultivars of banana resistant to all the pathogenic races of Foc, genetic engineering is the only option for the generation of resistant cultivars. Since Foc is a hemibiotrophic fungus, investigations into the roles played by different cell-death-related genes in the progression of Foc infection on host banana plants are important. Towards this goal, three such genes namely MusaDAD1, MusaBAG1 and MusaBI1 were identified in banana. The study of their expression pattern in banana cells in response to Foc inoculation (using Foc cultures or fungal toxins like fusaric acid and beauvericin) indicated that they were indeed differentially regulated by fungal inoculation. Among the three genes studied, MusaBAG1 showed the highest up-regulation upon Foc inoculation. Further, in order to characterize these genes in the context of Foc infection in banana, we generated transgenic banana plants constitutively overexpressing the three genes that were later subjected to Foc bioassays in a contained greenhouse. Among the three groups of transgenics tested, transformed banana plants overexpressing MusaBAG1 demonstrated the best resistance towards Foc infection. Further, these plants also showed the highest relative overexpression of the transgene (MusaBAG1) among the three groups of transformed plants generated. Our study showed for the first time that native genes like MusaBAG1 can be used to develop transgenic banana plants with efficient resistance towards pathogens like Foc. PMID:24996429

  14. Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes

    Science.gov (United States)

    Espinar, J.L.; Garcia, L.V.; Clemente, L.

    2005-01-01

    The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three saltmarsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management.

  15. Trend and pattern analyses of operational data from nuclear power plants

    International Nuclear Information System (INIS)

    One step towards maximizing the benefits gained from plant operating experience is the establishment of a rigorous scheme of classification and storage of operational data related to equipment failures and/or human errors. The analysis of data thus collected can fall into one of the following two categories: in-depth analysis of individual incidents which are considered to be of major significance from the safety point of view; and trend and pattern analyses of the stored data with the aim of identifying situations that warrant further studies or that require particular attention. In order to perform the second type of analyses, various approaches/systems are being used by organizations with interests in the nuclear power domain. Similar methodologies may be used in general industrial safety as well. For the purpose of facilitating a comparison between the different methods, the OECD/NEA Committee on the Safety of Nuclear Installations (CSNI) decided to organize a specialist meeting jointly with the Commission of the European Communities (CEC) for a systematic and comprehensive review of the matter

  16. Using phylogenetic, functional and trait diversity to understand patterns of plant community productivity.

    Directory of Open Access Journals (Sweden)

    Marc W Cadotte

    Full Text Available BACKGROUND: Two decades of research showing that increasing plant diversity results in greater community productivity has been predicated on greater functional diversity allowing access to more of the total available resources. Thus, understanding phenotypic attributes that allow species to partition resources is fundamentally important to explaining diversity-productivity relationships. METHODOLOGY/PRINCIPAL FINDINGS: Here we use data from a long-term experiment (Cedar Creek, MN and compare the extent to which productivity is explained by seven types of community metrics of functional variation: 1 species richness, 2 variation in 10 individual traits, 3 functional group richness, 4 a distance-based measure of functional diversity, 5 a hierarchical multivariate clustering method, 6 a nonmetric multidimensional scaling approach, and 7 a phylogenetic diversity measure, summing phylogenetic branch lengths connecting community members together and may be a surrogate for ecological differences. Although most of these diversity measures provided significant explanations of variation in productivity, the presence of a nitrogen fixer and phylogenetic diversity were the two best explanatory variables. Further, a statistical model that included the presence of a nitrogen fixer, seed weight and phylogenetic diversity was a better explanation of community productivity than other models. CONCLUSIONS: Evolutionary relationships among species appear to explain patterns of grassland productivity. Further, these results reveal that functional differences among species involve a complex suite of traits and that perhaps phylogenetic relationships provide a better measure of the diversity among species that contributes to productivity than individual or small groups of traits.

  17. Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes.

    Science.gov (United States)

    Espinar, José L; García, Luis V; Clemente, Luis

    2005-07-01

    The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three salt-marsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management. PMID:21646131

  18. Altitudinal patterns and controls of plant and soil nutrient concentrations and stoichiometry in subtropical China

    Science.gov (United States)

    He, Xianjin; Hou, Enqing; Liu, Yang; Wen, Dazhi

    2016-04-01

    Altitude is a determining factor of ecosystem properties and processes in mountains. This study investigated the changes in the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and their ratios in four key ecosystem components (forest floor litter, fine roots, soil, and soil microorganisms) along an altitudinal gradient (from 50 m to 950 m a.s.l.) in subtropical China. The results showed that soil organic C and microbial biomass C concentrations increased linearly with increasing altitude. Similar trends were observed for concentrations of total soil N and microbial biomass N. In contrast, the N concentration of litter and fine roots decreased linearly with altitude. With increasing altitude, litter, fine roots, and soil C:N ratios increased linearly, while the C:N ratio of soil microbial biomass did not change significantly. Phosphorus concentration and C:P and N:P ratios of all ecosystem components generally had nonlinear relationships with altitude. Our results indicate that the altitudinal pattern of plant and soil nutrient status differs among ecosystem components and that the relative importance of P vs. N limitation for ecosystem functions and processes shifts along altitudinal gradients.

  19. Techniques for analysing pattern formation in populations of stem cells and their progeny

    Directory of Open Access Journals (Sweden)

    Fozard John A

    2011-10-01

    Full Text Available Abstract Background To investigate how patterns of cell differentiation are related to underlying intra- and inter-cellular signalling pathways, we use a stochastic individual-based model to simulate pattern formation when stem cells and their progeny are cultured as a monolayer. We assume that the fate of an individual cell is regulated by the signals it receives from neighbouring cells via either diffusive or juxtacrine signalling. We analyse simulated patterns using two different spatial statistical measures that are suited to planar multicellular systems: pair correlation functions (PCFs and quadrat histograms (QHs. Results With a diffusive signalling mechanism, pattern size (revealed by PCFs is determined by both morphogen decay rate and a sensitivity parameter that determines the degree to which morphogen biases differentiation; high sensitivity and slow decay give rise to large-scale patterns. In contrast, with juxtacrine signalling, high sensitivity produces well-defined patterns over shorter lengthscales. QHs are simpler to compute than PCFs and allow us to distinguish between random differentiation at low sensitivities and patterned states generated at higher sensitivities. Conclusions PCFs and QHs together provide an effective means of characterising emergent patterns of differentiation in planar multicellular aggregates.

  20. The use of phylogeny to interpret cross-cultural patterns in plant use and guide medicinal plant discovery

    DEFF Research Database (Denmark)

    Saslis-Lagoudakis, C Haris; Klitgaard, Bente B; Forest, Félix;

    2011-01-01

    BACKGROUND: The study of traditional knowledge of medicinal plants has led to discoveries that have helped combat diseases and improve healthcare. However, the development of quantitative measures that can assist our quest for new medicinal plants has not greatly advanced in recent years...

  1. Expression Patterns of Cancer-Testis Antigens in Human Embryonic Stem Cells and Their Cell Derivatives Indicate Lineage Tracks

    OpenAIRE

    Olga Gordeeva; Tatyana Yakovleva; Galina Poljanskaya; Tatyana Krylova; Anna Koltsova; Nadya Lifantseva

    2011-01-01

    Pluripotent stem cells can differentiate into various lineages but undergo genetic and epigenetic changes during long-term cultivation and, therefore, require regular monitoring. The expression patterns of cancer-testis antigens (CTAs) MAGE-A2, -A3, -A4, -A6, -A8, -B2, and GAGE were examined in undifferentiated human embryonic stem (hES) cells, their differentiated derivatives, teratocarcinoma (hEC) cells, and cancer cell lines of neuroectodermal and mesodermal origin. Undifferentiated hES ce...

  2. Contrasting patterns of herbivore and predator pressure on invasive and native plants

    NARCIS (Netherlands)

    Engelkes, T.; Wouters, B.; Bezemer, T.M.; Harvey, J.A.; Putten, van der W.H.

    2012-01-01

    Invasive non-native plant species often harbor fewer herbivorous insects than related native plant species. However, little is known about how herbivorous insects on non-native plants are exposed to carnivorous insects, and even less is known on plants that have recently expanded their ranges within

  3. Simple and non-toxic fabrication of poly(vinyl alcohol)-patterned polymer surface for the formation of cell patterns

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Negative PVA patterns were formed on NPS substrates by selective ion irradiation. • The surface of PVA patterns was more hydrophilic than that of the NPS substrate. • Well-organized cell patterns were created on the PVA-patterned NPS substrates. • It can be due to the preferential adsorption of serum proteins on PVA patterns. - Abstract: In this study, a facile and non-toxic method for the formation of cell-adhesive poly(vinyl alcohol) (PVA) patterns on the surface of a non-biological polystyrene substrate (NPS) is developed to control cellular micro-organization. PVA thin films spin-coated onto the NPS are selectively irradiated with 150 keV H+ ions through a pattern mask and developed with deionized water to form negative-type PVA patterns. Well-defined stripe patterns of PVA with a width of 100 μm are created on the NPS at a higher fluence than 5 × 1015 ions/cm2, and their surface chemical compositions are changed by ion irradiation without any significant morphological change. Based on the results of the protein adsorption test and in vitro cell culture, cancer cells are preferentially adhered and proliferated onto the more hydrophilic PVA regions of the PVA-patterned NPS, resulting in well-defined cell patterns

  4. Simple and non-toxic fabrication of poly(vinyl alcohol)-patterned polymer surface for the formation of cell patterns

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, In-Tae; Jin, Yu-Ran [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Oh, Min-Suk [POSCO Technical Research Laboratories, 699 Gumho-dong, Gwangyang, Jeonnam 545-090 (Korea, Republic of); Jung, Chan-Hee, E-mail: jch@kaeri.re.kr [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Choi, Jae-Hak, E-mail: jaehakchoi@cnu.ac.kr [Department of Polymer Science and Engineering, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2014-10-15

    Graphical abstract: - Highlights: • Negative PVA patterns were formed on NPS substrates by selective ion irradiation. • The surface of PVA patterns was more hydrophilic than that of the NPS substrate. • Well-organized cell patterns were created on the PVA-patterned NPS substrates. • It can be due to the preferential adsorption of serum proteins on PVA patterns. - Abstract: In this study, a facile and non-toxic method for the formation of cell-adhesive poly(vinyl alcohol) (PVA) patterns on the surface of a non-biological polystyrene substrate (NPS) is developed to control cellular micro-organization. PVA thin films spin-coated onto the NPS are selectively irradiated with 150 keV H{sup +} ions through a pattern mask and developed with deionized water to form negative-type PVA patterns. Well-defined stripe patterns of PVA with a width of 100 μm are created on the NPS at a higher fluence than 5 × 10{sup 15} ions/cm{sup 2}, and their surface chemical compositions are changed by ion irradiation without any significant morphological change. Based on the results of the protein adsorption test and in vitro cell culture, cancer cells are preferentially adhered and proliferated onto the more hydrophilic PVA regions of the PVA-patterned NPS, resulting in well-defined cell patterns.

  5. Anhydrobiosis and programmed cell death in plants: Commonalities and Differences

    Directory of Open Access Journals (Sweden)

    Samer Singh

    2015-05-01

    Full Text Available Anhydrobiosis is an adaptive strategy of certain organisms or specialised propagules to survive in the absence of water while programmed cell death (PCD is a finely tuned cellular process of the selective elimination of targeted cell during developmental programme and perturbed biotic and abiotic conditions. Particularly during water stress both the strategies serve single purpose i.e., survival indicating PCD may also function as an adaptive process under certain conditions. During stress conditions PCD cause targeted cells death in order to keep the homeostatic balance required for the organism survival, whereas anhydrobiosis suspends cellular metabolic functions mimicking a state similar to death until reestablishment of the favourable conditions. Anhydrobiosis is commonly observed among organisms that have ability to revive their metabolism on rehydration after removal of all or almost all cellular water without damage. This feature is widely represented in terrestrial cyanobacteria and bryophytes where it is very common in both vegetative and reproductive stages of life-cycle. In the course of evolution, with the development of advanced vascular system in higher plants, anhydrobiosis was gradually lost from the vegetative phase of life-cycle. Though it is retained in resurrection plants that primarily belong to thallophytes and a small group of vascular angiosperm, it can be mostly found restricted in orthodox seeds of higher plants. On the contrary, PCD is a common process in all eukaryotes from unicellular to multicellular organisms including higher plants and mammals. In this review we discuss physiological and biochemical commonalities and differences between anhydrobiosis and PCD.

  6. On-chip cell sorting via patterned magnetic traps

    Science.gov (United States)

    Byvank, Tom; Prikockis, Michael; Chen, Aaron; Miller, Brandon; Chalmers, Jeffrey; Sooryakumar, Ratnasingham

    2015-03-01

    Due to their importance in research for the diagnosis and treatment of cancer, numerous schemes have been developed to sort rare cell populations, e.g., circulating tumor cells (CTCs), from a larger ensemble of cells. Here, we improve upon a previously developed microfluidic device (Lab Chip 13, 1172, (2013)) to increase throughput and sorting purity of magnetically labeled cells. The separation mechanism involves controlling magnetic forces by manipulating the magnetic domain structures of embedded permalloy microdisks with weak external fields. These forces move labeled cells from the input flow stream into an adjacent buffer flow stream. Such magnetically activated transfer separates the magnetic entities from their non-magnetic counterparts as the two flow streams split apart and move toward their respective outputs. Purity of the magnetic output is modulated by the withdrawal rate of the non-magnetic output relative to the inputs. A proof of concept shows that CTCs from metastatic breast cancer patients can be sorted, recovered from the device, and confirmed as CTCs using separate immunofluorescence staining and analysis. With further optimizations, the channel could become a useful device for high purity final sorting of enriched patient cell samples.

  7. A novel cell death gene acts to repair patterning defects in Drosophila melanogaster.

    Science.gov (United States)

    Tanaka, Kentaro M; Takahashi, Aya; Fuse, Naoyuki; Takano-Shimizu-Kouno, Toshiyuki

    2014-06-01

    Cell death is a mechanism utilized by organisms to eliminate excess cells during development. Here, we describe a novel regulator of caspase-independent cell death, Mabiki (Mabi), that is involved in the repair of the head patterning defects caused by extra copies of bicoid in Drosophila melanogaster. Mabiki functions together with caspase-dependent cell death mechanisms to provide robustness during development. PMID:24671768

  8. Discrete model of periodic pattern formation through a combined autocrine–juxtacrine cell signaling

    International Nuclear Information System (INIS)

    We model the formation of periodic patterns of gene expression in epithelial cell sheets driven by autocrine signaling coupled to juxtacrine lateral inhibition. The mathematical model is based on a continuous description of the extracellular matrix and a discrete cell-level description of the layer of cells, coupling the dynamics of diffusible ligands to the threshold-controlled cell-autonomous regulation with randomly fluctuating production rates. The results of numerical simulations indicate that propagating signaling waves emerge in a certain parametric domain, leading to the formation of a variety of either periodic or irregular patterns. For some selections of parameters, a propagating stripe of uniform expression leaves in its wake stationary periodic arrays. Coupling of autocrine and juxtacrine cell communication is essential for the pattern regularity and for the selection of expression patterns. Moreover, weak but non-vanishing noise levels are essential for the formation of regular patterns. Additional autocrine and cell-autonomous regulatory interactions can be introduced to increase the spacing of a periodic pattern. (paper)

  9. Spatial Patterns of Plant Litter and Sedimentation in a Tidal Freshwater Marsh and Implications for Marsh Persistence

    Science.gov (United States)

    Elmore, A. J.; Cadol, D. D.; Palinkas, C. M.; Engelhardt, K. A.

    2014-12-01

    The maintenance of marsh platform elevation under sea level rise is dependent on sedimentation and biomass conversion to soil organic material. These physical and biological processes interact within the tidal zone, resulting in elevation-dependent processes contributing to marsh accretion. Here we explore spatial pattern in plant litter, a variable related to productivity, to understand its role in physical and biological interactions in a freshwater marsh. Plant litter that persists through the dormant season has an extended period of influence on ecosystem processes. We conducted a field and remote sensing analysis of plant litter height, biomass, vertical cover, and stem density (collectively termed plant litter structure) at a tidal freshwater marsh located along the Potomac River estuary. We completed two years of repeat RTK GPS surveys with corresponding measurements of litter height (over 2000 observations) to train a non-parametric random forest decision tree to predict litter height. LiDAR and field observations show that plant litter height increases with increasing elevation, although important deviations from this relationship are apparent. These spatial patterns exhibit stability from year to year and lead to corresponding patterns in soil organic matter content, revealed by loss on ignition of surface sediments. The amount of mineral material embedded within plant litter decreases with increasing elevation, representing an important trade-off with litter structure. Therefore, at low elevations where litter structure is short and sparse, the role of plant litter is to capture sediment; at high elevations where litter structure is tall and dense, litter contributes organic matter to soil development. Despite these tradeoffs, changes in elevation over time are consistent across elevation, with only small positive differences in elevation gain over time at elevations where the most sediment is deposited or where litter exhibits the most biomass.

  10. Aspects of plant cell growth and the actin cytoskeleton: lessons from root hairs

    OpenAIRE

    Ruijter, de, A.

    1999-01-01

    The main topic the thesis addresses is the role of the actin cytoskeleton in the growth process of plant cells. Plant growth implies a combination of cell division and cell expansion. The cytoskeleton, which exists of microtubules and actin filaments, plays a major role in both processes. Before cell growth takes place, a new cell is formed by cell division. The orientation of the division plane most often predicts the orientation of cell expansion, and a correct positioning of the division p...

  11. A simple way to identify non-viable cells within living plant tissue using confocal microscopy

    Directory of Open Access Journals (Sweden)

    Truernit Elisabeth

    2008-06-01

    Full Text Available Abstract Background Plant cell death is a normal process during plant development. Mutant plants may exhibit misregulation of this process, which can lead to severe growth defects. Simple ways of visualising cell death in living plant tissues can aid the study of plant development and physiology. Results Spectral variants of the fluorescent SYTOX dyes were tested for their usefulness for the detection of non-viable cells within plant embryos and roots using confocal laser-scanning microscopy. The dyes were selective for non-viable cells and showed very little background staining in living cells. Simultaneous detection of SYTOX dye and fluorescent protein (e.g. GFP fluorescence was possible. Conclusion The fluorescent SYTOX dyes are useful for an easy and quick first assay of plant cell viability in living plant samples using fluorescence and confocal laser-scanning microscopy.

  12. Generating Within-Plant Spatial Distributions of an Insect Herbivore Based on Aggregation Patterns and Per-Node Infestation Probabilities.

    Science.gov (United States)

    Rincon, Diego F; Hoy, Casey W; Cañas, Luis A

    2015-04-01

    Most predator-prey models extrapolate functional responses from small-scale experiments assuming spatially uniform within-plant predator-prey interactions. However, some predators focus their search in certain plant regions, and herbivores tend to select leaves to balance their nutrient uptake and exposure to plant defenses. Individual-based models that account for heterogeneous within-plant predator-prey interactions can be used to scale-up functional responses, but they would require the generation of explicit prey spatial distributions within-plant architecture models. The silverleaf whitefly, Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae), is a significant pest of tomato crops worldwide that exhibits highly aggregated populations at several spatial scales, including within the plant. As part of an analytical framework to understand predator-silverleaf whitefly interactions, the objective of this research was to develop an algorithm to generate explicit spatial counts of silverleaf whitefly nymphs within tomato plants. The algorithm requires the plant size and the number of silverleaf whitefly individuals to distribute as inputs, and includes models that describe infestation probabilities per leaf nodal position and the aggregation pattern of the silverleaf whitefly within tomato plants and leaves. The output is a simulated number of silverleaf whitefly individuals for each leaf and leaflet on one or more plants. Parameter estimation was performed using nymph counts per leaflet censused from 30 artificially infested tomato plants. Validation revealed a substantial agreement between algorithm outputs and independent data that included the distribution of counts of both eggs and nymphs. This algorithm can be used in simulation models that explore the effect of local heterogeneity on whitefly-predator dynamics. PMID:26313173

  13. Interplay of migratory and division forces as a generic mechanism for stem cell patterns

    Science.gov (United States)

    Hannezo, Edouard; Coucke, Alice; Joanny, Jean-François

    2016-02-01

    In many adult tissues, stem cells and differentiated cells are not homogeneously distributed: stem cells are arranged in periodic "niches," and differentiated cells are constantly produced and migrate out of these niches. In this article, we provide a general theoretical framework to study mixtures of dividing and actively migrating particles, which we apply to biological tissues. We show in particular that the interplay between the stresses arising from active cell migration and stem cell division give rise to robust stem cell patterns. The instability of the tissue leads to spatial patterns which are either steady or oscillating in time. The wavelength of the instability has an order of magnitude consistent with the biological observations. We also discuss the implications of these results for future in vitro and in vivo experiments.

  14. An interplay of migratory and division forces as a generic mechanism for stem cell patterns

    CERN Document Server

    Hannezo, Edouard; Joanny, Jean-François

    2015-01-01

    In many adult tissues, stem cells and differentiated cells are not homogeneously distributed : stem cells are arranged in periodic "niches", and differentiated cells are constantly produced and migrate out of these niches. In this article, we provide a general theoretical framework to study mixtures of dividing and actively migrating particles, which we apply to biological tissues. We show in particular that the interplay between the stresses arising from active cell migration and stem cell division give rise to robust stem cell patterns. The instability of the tissue leads to spatial patterns which are either steady or oscillating in time. The wavelength of the instability has an order of magnitude consistent with the biological observations. We also discuss the implications of these results for future in vitro and in vivo experiments.

  15. Direct laser patterning of transparent ITO–Ag–ITO multilayer anodes for organic solar cells

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • ITO/Ag/ITO electrode was patterned by femtosecond laser. • The laser-patterned ITO/Ag/ITO electrode was electrically isolated. • Laser patterning is a promising patterning technology. - Abstract: Direct laser patterning of transparent ITO–Ag–ITO (IAI) multilayer anodes is investigated using a femtosecond fiber laser for application in organic solar cells (OSC) fabrication. By adjusting laser fluence and scan speed, we successfully patterned the IAI multilayer anode without changing the electrical or optical properties. At an optimized laser fluence of 0.6 J/cm2 and a scan speed of 200 mm/s, the patterned IAI multilayer was electrically isolated with a clean edge. The metallic Ag interlayer of the IAI multilayer plays an important role in direct laser patterning because it absorbed the laser and increases the maximum temperature in the IAI multilayer. In addition, the Ag layer could effectively decrease the temperature of the IAI multilayer after irradiation of laser. The OSC fabricated on the laser patterned IAI multilayer showed power conversion efficiencies of 3.12% (Ag 8 nm) and 2.85% (Ag 12 nm). Successful operation of the OSC indicates that direct laser patterning of IAI multilayer anodes is a promising, simple patterning technology for fabrication of IAI-based OSCs

  16. Patterns of efficiency and degradation of composite polymer solar cells

    NARCIS (Netherlands)

    Jeranko, T; Tributsch, H; Sariciftci, NS; Hummelen, JC

    2004-01-01

    Bulk-heterojunction plastic solar cells (PSC) produced from a conjugated polymer, poly(2-methoxy-5-(3',7'-dimethyloctyl-oxy)-1,4-phenylenevinylene) (MDMO-PPV), and a methanofullerene [6,6]-phenyl C-61-butyric acid methyl ester (PCBM) were investigated using photocurrent imaging techniques to determi

  17. High-throughput screening of monoclonal antibodies against plant cell wall glycans by hierarchical clustering of their carbohydrate microarray binding profiles

    DEFF Research Database (Denmark)

    Moller, Isabel; Marcus, Susan E.; Haeger, Ash;

    2007-01-01

    Antibody-producing hybridoma cell lines were created following immunisation with a crude extract of cell wall polymers from the plant Arabidopsis thaliana. In order to rapidly screen the specificities of individual monoclonal antibodies (mAbs), their binding to microarrays containing 50 cell wall...... investigated using subsequent immunochemical and biochemical analyses and two novel mAbs are described in detail. mAb LM13 binds to an arabinanase-sensitive pectic epitope and mAb LM14, binds to an epitope occurring on arabinogalactan-proteins. Both mAbs display novel patterns of recognition of cell walls in...... plant materials....

  18. Spatial Patterning of Newly-Inserted Material during Bacterial Cell Growth

    Science.gov (United States)

    Ursell, Tristan

    2012-02-01

    In the life cycle of a bacterium, rudimentary microscopy demonstrates that cell growth and elongation are essential characteristics of cellular reproduction. The peptidoglycan cell wall is the main load-bearing structure that determines both cell shape and overall size. However, simple imaging of cellular growth gives no indication of the spatial patterning nor mechanism by which material is being incorporated into the pre-existing cell wall. We employ a combination of high-resolution pulse-chase fluorescence microscopy, 3D computational microscopy, and detailed mechanistic simulations to explore how spatial patterning results in uniform growth and maintenance of cell shape. We show that growth is happening in discrete bursts randomly distributed over the cell surface, with a well-defined mean size and average rate. We further use these techniques to explore the effects of division and cell wall disrupting antibiotics, like cephalexin and A22, respectively, on the patterning of cell wall growth in E. coli. Finally, we explore the spatial correlation between presence of the bacterial actin-like cytoskeletal protein, MreB, and local cell wall growth. Together these techniques form a powerful method for exploring the detailed dynamics and involvement of antibiotics and cell wall-associated proteins in bacterial cell growth.[4pt] In collaboration with Kerwyn Huang, Stanford University.

  19. Cloning and analysis of genes regulating plant cell growth

    International Nuclear Information System (INIS)

    The aims of this work are to identify, clone and analyze genes involved in the regulation of plant cell growth. To do this, we have induced tumors on Arabidopsis thaliana by exposing seed or germinating seedlings to ionizing radiation. The tumors which developed on the plants derived from these seed were excised and established in culture. Unlike normal tissue explants, the tumors are able to grow on hormone-free medium suggesting changes in growth control (either hormonal or other) induced by the radiation exposure. This progress report describes work aimed at characterizing these tumors at the physiological and cellular levels and at determining the molecular basis of the changes leading to the tumorous phenotype

  20. Genetic changes induced in higher plant cells by a laser microbeam

    International Nuclear Information System (INIS)

    Introducing foreign genes into higher plants has proved to be complicated, with the exception of transformation of protoplasts of some plants (Negrutiu et al. 1987). In particular, culture of protoplasts and regeneration to plants are difficult in many monocotyledonous crops. Therefore, it would be desirable to avoid extensive tissue culture by introducing cloned genes directly into cells. A laser microbeam can perforate plant cell walls, thus facilitating uptake of genes into cells

  1. Actin based processes that could determine the cytoplasmic architecture of plant cells

    NARCIS (Netherlands)

    Honing, van der H.S.; Emons, A.M.C.; Ketelaar, M.J.

    2007-01-01

    Actin polymerisation can generate forces that are necessary for cell movement, such as the propulsion of a class of bacteria, including Listeria, and the protrusion of migrating animal cells. Force generation by the actin cytoskeleton in plant cells has not been studied. One process in plant cells t

  2. Microfluidic monitoring of programmed cell death in living plant seed tissue

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Zor, Kinga; Svensson, Birte; Emnéus, Jenny; Dufva, Martin; Finnie, Christine

    Programmed cell death (PCD) is a highly regulated process in which cells are dismantled. Reactive oxygen species (ROS) are involved in PCD in plants, but the relationship between and mechanisms behind ROS and PCD are only poorly understood in plant cells compared to in animal cells (Gechev, Tsanko...

  3. A radioimmunoassay for lignin in plant cell walls

    International Nuclear Information System (INIS)

    Lignin detection and determination in herbaceous tissue requires selective, specific assays which are not currently available. A radioimmunoassay (RIA) was developed to study lignin metabolism in these tissues. A β-aryl ether lignin model compound was synthesized, linked to keyhole limpet hemocyanin using a water-soluble carbodiimide, and injected into rabbits. The highest titer of the antiserum obtained was 34 ηg/mL of model derivatized BSA. An in vitro system was developed to characterize the RIA. The model compound was linked to amino activated polyacrylamide beads to mimic lignin in the cell walls. 125I Radiolabelled protein A was used to detect IgG antibody binding. The RIA was shown in the in vitro system to exhibit saturable binding. The amount of antibody bound decreased when the serum was diluted. Immunoelectrophoresis and competitive binding experiments confirmed that both aromatic rings of the lignin model compound had been antigenic. Chlorogenic acid, a phenolic known to be present in plant cells, did not compete for antibody binding. The RIA was used to measure lignin in milled plant samples and barley seedlings. Antiserum binding to wheat cell walls and stressed barley segments was higher than preimmune serum binding. Antibody binding to stressed barley tissue decreased following NaClO2 delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed

  4. Adaptive Potential for the Invasion of Novel Host Plants in the Bean Weevil: Patterns of the Reproductive Behavior in Populations That Used Different Host Plants

    Directory of Open Access Journals (Sweden)

    Dragana Milanović

    2007-01-01

    Full Text Available The goal of this work was to examine interpopulation patterns in the reproductive behavior of populations of bean weevil (Acanthoscelides obtectus Say; Coleoptera: Bruchidae that had different levels of specialization on their native host plant – the bean (Phaseolus vulgaris L., as well as on a novel host plant – the chickpea (Cicer arietinum Thorn. The obtained pattern of interpopulation mating behavior seemed exactly as if the males on chickpea had evolved a specific odor and/or a courtship ritual that females of populationson bean found repulsive. Unlike females, the males of bean populations seemed to be willing to mate with females from the population on chickpea equally as with their own females. Such an asymmetric pattern of reproductive isolation between populations ofa species has been often considered an initial phase of a process of speciation. Thus, our results could be a good starting point for further, thorough examination of both the role of the level of host specialization in females and the role of biochemical characteristics of male pheromone (and/or their cuticular hydrocarbones in the evolution of pre-reproductive isolation between insect populations.As the results of this study, together those of previous studies on A. obtectus, suggest great evolutionary potential for invasions of and fast specialization on novel host plants, they could provide valuable information for the development of long-term strategiesunder the programmes of Integrated Pest Management.

  5. Fabrication of biomimetically-patterned surfaces and their application to probing plant-bacteria interactions

    Science.gov (United States)

    Understanding of plant-bacterial interactions is of critical importance for developing effective control measures against infectious diseases caused by foodborne human pathogens. However, limitations of existing scientific tools to access and evaluate natural plant tissues, and the large variations ...

  6. Atmospheric constraints on Plant Water Use Efficiency drivers and patterns of changes since 1900

    Science.gov (United States)

    Groenendijk, Margriet; Cox, Peter; Booth, Ben; Lambert, Hugo

    2013-04-01

    Water Use Efficiency (WUE) controls the relationship between the ecosystem water and carbon balance. Because WUE responds to environmental changes it can be used as a metric to quantify the effect of climate change on ecosystems. The actual WUEeco is defined as a ratio of gross primary production and transpiration fluxes. On the leaf scale this is equal to the atmospheric WUEatm, which is a function of the ambient and internal CO2 concentration, the saturated specific humidity and relative humidity. Using observations and the JULES and HadCM3 models we explore on which temporal and spatial scales WUEeco and WUEatm are equal, and how they respond to climate change. Leaf level definitions are valid at site level, where annual WUEeco and WUEatm simulated with JULES are equal and linearly increasing with atmospheric CO2 concentration for a range of sites. For drier sites lower values of both were simulated. The simulated values are within the same range as values derived from eddy covariance observations. Having shown the near equivalence between WUEeco and WUEatm for specific sites, we can use the formula for WUEatm to estimate the change in plant WUE over the 20th century, using observed climatological data and CO2 concentrations. In general WUE is found to increase strongly with the CO2 concentration, but this is offset by warming and drying that increases evaporative demand and therefore reduces WUE. As a result we find complex spatio-temporal patterns of changes in WUE, resulting from the differing drivers of climate change and variation. For example, warming due to the reduction in atmospheric aerosol pollution since the late 1980s reduced WUE in some previously heavily-polluted regions despite the ongoing increase in atmospheric CO2. We will describe the methods used to reconstruct WUE from observations, and discuss the spatial and temporal variation of WUE since 1900.

  7. Differing Organic Acid Exudation Pattern Explains Calcifuge and Acidifuge Behaviour of Plants

    OpenAIRE

    Tyler, Germund; Ström, Lena

    1995-01-01

    Many vascular plant species are unable to colonize calcareous sites. Thus, the floristic composition of adjacent limestone and acid silicate soils differs greatly. The inability of calcifuge plants to establish in limestone sites seems related to a low capacity of such plants to solubilize and absorb Fe or phosphate from these soils. Until now, mechanisms regulating this differing ability of plants to colonize limestone sites have not been elucidated. We propose that contrasting exudation of ...

  8. Patterns of spread of clear cell ovarian cancer: Case report and case series ☆

    OpenAIRE

    Kumar, Aalok; Gilks, C. Blake; Mar, Colin; Santos, Jennifer; Tinker, Anna V.

    2013-01-01

    Highlights • Although patterns of metastases in ovarian clear cell cancer are not well described, patients may initially present with bone metastases. • Clear cell carcinoma with bone metastases is responsive to radiation therapy. • Bone metastases are not common in patients with ovarian high grade serous cancer.

  9. Pigment cell movement is not required for generation of Turing patterns in zebrafish skin

    Science.gov (United States)

    Bullara, D.; De Decker, Y.

    2015-01-01

    The zebrafish is a model organism for pattern formation in vertebrates. Understanding what drives the formation of its coloured skin motifs could reveal pivotal to comprehend the mechanisms behind morphogenesis. The motifs look and behave like reaction–diffusion Turing patterns, but the nature of the underlying physico-chemical processes is very different, and the origin of the patterns is still unclear. Here we propose a minimal model for such pattern formation based on a regulatory mechanism deduced from experimental observations. This model is able to produce patterns with intrinsic wavelength, closely resembling the experimental ones. We mathematically prove that their origin is a Turing bifurcation occurring despite the absence of cell motion, through an effect that we call differential growth. This mechanism is qualitatively different from the reaction–diffusion originally proposed by Turing, although they both generate the short-range activation and the long-range inhibition required to form Turing patterns. PMID:25959141

  10. The Glycoprofile Patterns of Endothelial Cells in Usual Interstitial Pneumonia

    OpenAIRE

    Barkhordari, A.; CJP Jones; RW Stoddart; SF McClure; McClure, J; S Rahimi Moghadam

    2014-01-01

    [THIS ARTICLE HAS BEEN RETRACTED FOR DUPLICATE PUBLICATION] Background: The pathological classification of cryptogenic fibrosing alveolitis has been a matter of debate and controversy for histopathologists.Objective: To identify and specify the glycotypes of capillary endothelial cells in usual interstitial pneumonia (UIP) compared to those found in normal tissue.Methods: Sections of formalin-fixed, paraffin-embedded blocks from 16 cases of UIP were studied by lectin histochemistry with a pan...

  11. The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

    Directory of Open Access Journals (Sweden)

    Asako eUchiyama

    2014-11-01

    Full Text Available Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV and the Tobamovirus Tobacco mosaic virus (TMV through plasmodesmata (Lewis and Lazarowitz, 2010. To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV, the Caulimovirus Cauliflower mosaic virus (CaMV and the Tobamovirus Turnip vein clearing virus (TVCV, which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP, Tobamoviruses (TVCV and TMV 30K protein and Potyviruses (TuMV P3N-PIPO to alter PD and thereby mediate virus cell-to-cell spread.

  12. Direct fuel cell power plants: the final steps to commercialization

    Science.gov (United States)

    Glenn, Donald R.

    Since the last paper presented at the Second Grove Fuel Cell Symposium, the Energy Research Corporation (ERC) has established two commercial subsidiaries, become a publically-held firm, expanded its facilities and has moved the direct fuel cell (DFC) technology and systems significantly closer to commercial readiness. The subsidiaries, the Fuel Cell Engineering Corporation (FCE) and Fuel Cell Manufacturing Corporation (FCMC) are perfecting their respective roles in the company's strategy to commercialize its DFC technology. FCE is the prime contractor for the Santa Clara Demonstration and is establishing the needed marketing, sales, engineering, and servicing functions. FCMC in addition to producing the stacks and stack modules for the Santa Clara demonstration plant is now upgrading its production capability and product yields, and retooling for the final stack scale-up for the commercial unit. ERC has built and operated the tallest and largest capacities-to-date carbonate fuel cell stacks as well as numerous short stacks. While most of these units were tested at ERC's Danbury, Connecticut (USA) R&D Center, others have been evaluated at other domestic and overseas facilities using a variety of fuels. ERC has supplied stacks to Elkraft and MTU for tests with natural gas, and RWE in Germany where coal-derived gas were used. Additional stack test activities have been performed by MELCO and Sanyo in Japan. Information from some of these activities is protected by ERC's license arrangements with these firms. However, permission for limited data releases will be requested to provide the Grove Conference with up-to-date results. Arguably the most dramatic demonstration of carbonate fuel cells in the utility-scale, 2 MW power plant demonstration unit, located in the City of Santa Clara, California. Construction of the unit's balance-of-plant (BOP) has been completed and the installed equipment has been operationally checked. Two of the four DFC stack sub-modules, each

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  14. The Fluorescence Methods to Study Neurotransmitters (Biomediators) in Plant Cells.

    Science.gov (United States)

    Roshchina, Victoria V

    2016-05-01

    Fluorescence as a parameter for analysis of intracellular binding and localization of neurotransmitters also named biomediators (acetylcholine and biogenic amines such as catecholamines, serotonin, histamine) as well as their receptors in plant cells has been estimated basing on several world publications and own experiments of the author. The subjects of the consideration were 1. application of reagents forming fluorescent products (for catecholamines - glyoxylic acid, for histamine - formaldehyde or ortho-phthalic aldehyde) to show the presence and binding of the compounds in cells, 2. binding of their fluorescent agonists and antagonists with cell, 3. effects of the compounds, their agonists and antagonists on autofluorescence, 4. action of external factors on the accumulation of the compounds in cells. How neurotransmitters can bind to certain cellular compartments has been shown on intact individual cells (vegetative microspores, pollens, secretory cells) and isolated organelles. The staining with reagents on biogenic amines leads to the appearance blue or blue-green emission on the surface and excretions of intact cells as well in some DNA-containing organelles within cells. The difference between autofluorescence and histochemically induced fluorescence may reflect the occurrence and amount of biogenic amines in the cells studied. Ozone and salinity as external factors can regulate the emission of intact cells related to biogenic amines. After the treatment of isolated cellular organelles with glyoxylic acid blue emission with maximum 460-475 nm was seen in nuclei and chloroplasts (in control variants in this spectral region the noticeable emission was absent) and very expressive fluorescence (more than twenty times as compared to control) in the vacuoles. After exposure to ortho-phthalic aldehyde blue emission was more noticeable in nuclei and chloroplasts. Fluorescent agonists (muscarine, 6,7-diOHATN, BODIPY-dopamine or BODIPY-5HT) or antagonists (d

  15. Theoretical performance of multi-layer grid patterns for solar cells

    Science.gov (United States)

    Flat, A.; Milnes, A. G.

    1979-01-01

    Multilayer grid patterns consist of fine closely spaced grid lines overlaid by coarser patterns of wider and thicker grid lines to collect the current from the finer grids with low series voltage drop and low active-layer sheet losses. An analytical approach leads to closed form solutions with simple relationships between the power losses in the active layer, in the grid and shadowing losses for optimum design proportions. The results show that multilayer grids, with line thickness equal to line width, greatly reduce losses in cell efficiency under concentration conditions of high current collection. (AlGa)As-pn GaAs cells of areas 1-25 sq cm and sheet resistance 40 ohms/square are considered. Also the performance of a n/p GaAs cell of dimensions 10 x 10 cm is studied. With optimized grid patterns high efficiencies are predicted for large area cells.

  16. Linear patterning of magnetically labeled Dictyostelium cells to display confined development

    Energy Technology Data Exchange (ETDEWEB)

    Frasca, Guillaume; Raynaud, Franck; Bacri, Jean-Claude; Gazeau, Florence; Wilhelm, Claire [Laboratoire Matiere et Systemes Complexes (MSC), UMR 7057 CNRS et Universite Paris-Diderot, Paris (France)], E-mail: claire.wilhelm@univ-paris-diderot.fr

    2008-05-21

    In severe nutriment conditions, the social amoeba Dictyostelium discoideum enters a particular life cycle where it forms multicellular patterns to achieve aggregation. Extensively observed from an initial dispersed state, its developmental program can usefully be studied from a confined population to implement theoretical developments regarding biological self-organization. The challenge is then to form a cell assembly of well-defined geometrical dimensions without hindering cell behavior. To achieve this goal, we imposed transient constraints by applying temporary external magnetic gradients to trap magnetically labeled cells. Deposits of various numbers of cells were geometrically characterized for different magnetic exposure conditions. We demonstrated that the cell deposit was organized as a three-dimensional (3D) structure by both stacking layers of cells and extending these layers in the substrate plane. This structure evolves during the aggregation phase, forming periodic aggregative centers along the linear initial pattern.

  17. Studies on distribution pattern of 14C-assimilates in relation to vascular pattern derived from phyllotaxis of tomato plants

    International Nuclear Information System (INIS)

    The association of distribution of photosynthetic assimilates in tomato with phyllotaxis and arrangement of the vascular system was studied. To ascertain the phyllotaxis of tomato plants, which was alternate with four orthostichies with devergence of 90° (270°) and 180°, the vascular system was revealed by methylene blue (0.5%), eothine (1.0%) and fuchsin (1.0%) from leaf petioles and the distribution of photosynthetic assmilates was measured by 14C. The vascular system of tomato basically consisted of four orthostichies with two vascular bundles from each leaf. The arrangement of the vascular systems evidently affected the movement of 14C-assimilates to sinks. Such movement from each leaf was affected by the degree of connection of the vascular bundles. Since tomato has a sympodial branching system, the leaf which is apparently situated just above the inflorescence differentiated before the inflorescence. The vascular bundles of the leaf of the sympodial branch around the inflorescence developed between the inflorescence and the leaf just above it. This results in a comparatively small proportion of distribution to the inflorescence from the leaf just above it

  18. Identification and localization of transformed cells in agrobacterium tumefaciens-induced plant tumors

    Science.gov (United States)

    Rezmer; Schlichting; Wachter; Ullrich

    1999-10-01

    Agrobacterium tumefaciens-induced tumors of dicotyledonous plants consist of well-defined vascular bundle-like structures originating from transformed cells. The current view that 25% of the tumor cells are transformed has been re-investigated by using beta-glucuronidase (gus)-gene-containing wild-type bacteria (A281 p35S gus-int). Regularly growing stem and leaf tumors showed irregular GUS-staining patterns in the different plant species, Ricinus communis L., Cucurbita maxima L., Vicia faba L. and Kalanchoe daigremontiana Hamet et Perrier. Variable staining and inconsistency between staining and tumor growth suggested an inhibition of gus expression. By polymerase chain reaction (PCR) and reverse transcriptase-PCR analyses it became evident that gus is also integrated into the DNA of unstainable tumor parts but not expressed. These results and area calculations of tissues unable to contain the bacterial transferred-DNA with gus provide strong evidence that in A. tumefaciens-induced tumors most cells, or even all, are transformed, i.e. ca. 100%. PMID:10550620

  19. Muscarinic signaling influences the patterning and phenotype of cholinergic amacrine cells in the developing chick retina

    Directory of Open Access Journals (Sweden)

    Fischer Andy J

    2008-02-01

    Full Text Available Abstract Background Many studies in the vertebrate retina have characterized the differentiation of amacrine cells as a homogenous class of neurons, but little is known about the genes and factors that regulate the development of distinct types of amacrine cells. Accordingly, the purpose of this study was to characterize the development of the cholinergic amacrine cells and identify factors that influence their development. Cholinergic amacrine cells in the embryonic chick retina were identified by using antibodies to choline acetyltransferase (ChAT. Results We found that as ChAT-immunoreactive cells differentiate they expressed the homeodomain transcription factors Pax6 and Islet1, and the cell-cycle inhibitor p27kip1. As differentiation proceeds, type-II cholinergic cells, displaced to the ganglion cell layer, transiently expressed high levels of cellular retinoic acid binding protein (CRABP and neurofilament, while type-I cells in the inner nuclear layer did not. Although there is a 1:1 ratio of type-I to type-II cells in vivo, in dissociated cell cultures the type-I cells (ChAT-positive and CRABP-negative out-numbered the type-II cells (ChAT and CRABP-positive cells by 2:1. The relative abundance of type-I to type-II cells was not influenced by Sonic Hedgehog (Shh, but was affected by compounds that act at muscarinic acetylcholine receptors. In addition, the abundance and mosaic patterning of type-II cholinergic amacrine cells is disrupted by interfering with muscarinic signaling. Conclusion We conclude that: (1 during development type-I and type-II cholinergic amacrine cells are not homotypic, (2 the phenotypic differences between these subtypes of cells is controlled by the local microenvironment, and (3 appropriate levels of muscarinic signaling between the cholinergic amacrine cells are required for proper mosaic patterning.

  20. Cell cycle and cell death are not necessary for appressorium formation and plant infection in the fungal plant pathogen Colletotrichum gloeosporioides

    OpenAIRE

    Barhoom Sima; Nesher Iris; Sharon Amir

    2008-01-01

    Abstract Background In order to initiate plant infection, fungal spores must germinate and penetrate into the host plant. Many fungal species differentiate specialized infection structures called appressoria on the host surface, which are essential for successful pathogenic development. In the model plant pathogen Magnaporthe grisea completion of mitosis and autophagy cell death of the spore are necessary for appressoria-mediated plant infection; blocking of mitosis prevents appressoria forma...

  1. The effects of topographical patterns and sizes on neural stem cell behavior.

    Directory of Open Access Journals (Sweden)

    Lin Qi

    Full Text Available Engineered topographical manipulation, a paralleling approach with conventional biochemical cues, has recently attracted the growing interests in utilizations to control stem cell fate. In this study, effects of topological parameters, pattern and size are emphasized on the proliferation and differentiation of adult neural stem cells (ANSCs. We fabricate micro-scale topographical Si wafers with two different feature sizes. These topographical patterns present linear micro-pattern (LMP, circular micro-pattern (CMP and dot micro-pattern (DMP. The results show that the three topography substrates are suitable for ANSC growth, while they all depress ANSC proliferation when compared to non-patterned substrates (control. Meanwhile, LMP and CMP with two feature sizes can both significantly enhance ANSC differentiation to neurons compared to control. The smaller the feature size is, the better upregulation applies to ANSC for the differentiated neurons. The underlying mechanisms of topography-enhanced neuronal differentiation are further revealed by directing suppression of mitogen-activated protein kinase/extracellular signaling-regulated kinase (MAPK/Erk signaling pathway in ANSC using U0126, known to inhibit the activation of Erk. The statistical results suggest MAPK/Erk pathway is partially involved in topography-induced differentiation. These observations provide a better understanding on the different roles of topographical cues on stem cell behavior, especially on the selective differentiation, and facilitate to advance the field of stem cell therapy.

  2. Secretion mechanisms of volatile organic compounds in specialized cells of aromatic plants

    OpenAIRE

    Caissard, Jean-Claude; Joly, Caroline; Bergougnoux, Véronique; Hugueney, Philippe; Mauriat, Mélanie; Baudino, Sylvie

    2004-01-01

    The present review focuses on cells secreting volatile odorant compounds. This cell type is found in a wide variety of plants, grouped under the term aromatic plants. Such secreting cells are very diverse in morphology, from highly specialized trichomes to nonspecialized cells, including the secretory epidermal cells of petals and osmophores. In these various types of cell, the biosynthetic pathways of three main groups of volatile organic compounds are recognized: isoprenoids, fatty acid der...

  3. Hippocampal Place Cell Firing Patterns can Induce Long-Term Synaptic Plasticity In Vitro

    OpenAIRE

    Isaac, John T. R.; Buchanan, Katherine A.; Muller, Robert U.; Mellor, Jack R.

    2009-01-01

    In the hippocampus, synaptic strength between pyramidal cells is modifiable by NMDA receptor (NMDAR)-dependent long-term potentiation (LTP) and long-term depression (LTD), both of which require coincident pre- and postsynaptic activity. In vivo, many pyramidal cells exhibit location-specific activity patterns and are known as “place cells”. The combination of these factors suggests that synaptic plasticity will be induced at synapses connecting place cells with overlapping firing fields, sinc...

  4. Cell division pattern influences gene expression in the shoot apical meristem

    OpenAIRE

    Wyrzykowska, Joanna; Fleming, Andrew

    2003-01-01

    The shoot apical meristem of angiosperms shows a highly conserved cellular architecture in which a change of cell division orientation correlates with early events of leaf initiation. However, the causal role of this altered cellular parameter in leaf formation is debatable. We have used the dynamin-like protein phragmoplastin as a tool to modify the pattern of cell division within the apical meristem. Taking a microinduction approach, we show that local alteration in cell division orientatio...

  5. Altered growth patterns in vitro of human papillary transitional carcinoma cells.

    OpenAIRE

    Reznikoff, C. A.; Gilchrist, K. W.; Norback, D. H.; Cummings, K. B.; ERTÜRK, E.; Bryan, G. T.

    1983-01-01

    In vitro growth patterns and morphologic characteristics of five low-grade human papillary transitional cell carcinomas (TCCs) were compared and contrasted with those of normal human urothelial cells in culture. Biopsies of TCC were performed by transurethral resection. Specimens of normal human ureters were obtained surgically. Singly dispersed TCC cells grew in 0.3% agarose semisolid medium with a cloning efficiency ranging from 0.02% to 0.71%. Singly dispersed normal ureteral urothelial ce...

  6. Consolidated pretreatment and hydrolysis of plant biomass expressing cell wall degrading enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Raab, R. Michael; Zhang, Dongcheng; Bougri, Oleg

    2016-02-02

    Methods for consolidated pretreatment and hydrolysis of genetically engineered plants expressing cell wall degrading enzymes are provided. Expression cassettes and vectors for making transgenic plants are described. Plants engineered to express one or more cell wall degrading enzymes using expression cassettes and vectors of the invention are also provided.

  7. CYCLODEXTRINS AS A USEFUL TOOL FOR BIOCONVERSIONS IN PLANT-CELL BIOTECHNOLOGY

    NARCIS (Netherlands)

    VANUDEN, W; WOERDENBAG, HJ; PRAS, N

    1994-01-01

    The application of cyclodextrins as precursor solubilizers in biotechnological processes, in which plant cells are involved, is new. In this paper the possibilities for cyclodextrin facilitated bioconversions by freely suspended and/or immobilized plant cells or plant enzymes are demonstrated. After

  8. Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

    Science.gov (United States)

    Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

    2016-01-01

    Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs. PMID:27187017

  9. Engineered antifouling microtopographies: surface pattern effects on cell distribution.

    Science.gov (United States)

    Decker, Joseph T; Sheats, Julian T; Brennan, Anthony B

    2014-12-23

    Microtopography has been observed to lead to altered attachment behavior for marine fouling organisms; however, quantification of this phenomenon is lacking in the scientific literature. Here, we present quantitative measurement of the disruption of normal attachment behavior of the fouling algae Ulva linza by antifouling microtopographies. The distribution of the diatom Navicula incerta was shown to be unaffected by the presence of topography. The radial distribution function was calculated for both individual zoospores and cells as well as aggregates of zoospores from attachment data for a variety topographic configurations and at a number of different attachment densities. Additionally, the screening distance and maximum values were mapped according to the location of zoospore aggregates within a single unit cell. We found that engineered topographies decreased the distance between spore aggregates compared to that for a smooth control surface; however, the distributions for individual spores were unchanged. We also found that the local attachment site geometry affected the screening distance for aggregates of zoospores, with certain geometries decreasing screening distance and others having no measurable effect. The distribution mapping techniques developed and explored in this article have yielded important insight into the design parameters for antifouling microtopographies that can be implemented in the next generation of antifouling surfaces. PMID:25420235

  10. The elicitor-inducible alfalfa isoflavone reductase promoter confers different patterns of developmental expression in homologous and heterologous transgenic plants.

    Science.gov (United States)

    Oommen, A; Dixon, R A; Paiva, N L

    1994-01-01

    In legumes, the synthesis of infection- and elicitor-inducible antimicrobial phytoalexins occurs via the isoflavonoid branch of the phenylpropanoid pathway. To study transcriptional regulation of isoflavonoid pathway-specific genes, we have isolated the gene encoding isoflavone reductase (IFR), which is the enzyme that catalyzes the penultimate step in the synthesis of the phytoalexin medicarpin in alfalfa. Chimeric gene fusions were constructed between 765- and 436-bp promoter fragments of the IFR gene and the beta-glucuronidase reporter gene and transferred to alfalfa and tobacco by Agrobacterium-mediated transformation. Both promoter fragments conferred elicitor-mediated expression in cell suspension cultures derived from transgenic plants of both species and fungal infection-mediated expression in leaves of transgenic alfalfa. Developmental expression directed by both promoter fragments in transgenic alfalfa was observed only in the root meristem, cortex, and nodules, which is consistent with the accumulation of endogenous IFR transcripts. However, in transgenic tobacco, expression from the 765-bp promoter was observed in vegetative tissues (root meristem and cortex, inner vascular tissue of stems and petioles, leaf tips, and stem peripheries adjacent to petioles) and in reproductive tissues (stigma, placenta, base of the ovary, receptacle, seed, tapetal layer, and pollen grains), whereas the 436-bp promoter was expressed only in fruits, seed, and pollen. These data indicate that infection/elicitor inducibility of the IFR promoter in both species and developmental expression in alfalfa are determined by sequences downstream of position -436, whereas sequences between -436 and -765 confer a complex pattern of strong ectopic developmental expression in the heterologous species that lacks the isoflavonoid pathway. PMID:7866024

  11. Plant micrometabolomics: the analysis of endogenous metabolites present in a plant cell or tissue.

    Science.gov (United States)

    Moco, Sofia; Schneider, Bernd; Vervoort, Jacques

    2009-04-01

    Identification and quantification of metabolites occurring within specific cell types or single cells of plants and other organisms is of particular interest for natural product chemistry, chemical ecology, and biochemistry in general. The integration of studies at the gene, transcript, protein and metabolite levels in localized regions will provide useful information for the understanding of biology as a system. In this review, we summarize the latest developments in the analysis of metabolites present in small samples, micrometabolomics, dealing with sample preparation methods, with focus on laser-assisted microdissection, and the analytical technologies used. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) are among the most emergent technologies in metabolomics, enabling the shortest route toward metabolite identification. PMID:19714872

  12. Using Plant Functional Traits and Phylogenies to Understand Patterns of Plant Community Assembly in a Seasonal Tropical Forest in Lao PDR.

    Directory of Open Access Journals (Sweden)

    Manichanh Satdichanh

    Full Text Available Plant functional traits reflect different evolutionary responses to environmental variation, and among extant species determine the outcomes of interactions between plants and their environment, including other plant species. Thus, combining phylogenetic and trait-based information can be a powerful approach for understanding community assembly processes across a range of spatial scales. We used this approach to investigate tree community composition at Phou Khao Khouay National Park (18°14'-18°32'N; 102°38'- 102°59'E, Laos, where several distinct forest types occur in close proximity. The aim of our study was to examine patterns of plant community assembly across the strong environmental gradients evident at our site. We hypothesized that differences in tree community composition were being driven by an underlying gradient in soil conditions. Thus, we predicted that environmental filtering would predominate at the site and that the filtering would be strongest on sandier soil with low pH, as these are the conditions least favorable to plant growth. We surveyed eleven 0.25 ha (50x50 m plots for all trees above 10 cm dbh (1221 individual trees, including 47 families, 70 genera and 123 species and sampled soils in each plot. For each species in the community, we measured 11 commonly studied plant functional traits covering both the leaf and wood economic spectrum traits and we reconstructed a phylogenetic tree for 115 of the species in the community using rbcL and matK sequences downloaded from Genebank (other species were not available. Finally we compared the distribution of trait values and species at two scales (among plots and 10x10m subplots to examine trait and phylogenetic community structures. Although there was strong evidence that an underlying soil gradient was determining patterns of species composition at the site, our results did not support the hypothesis that the environmental filtering dominated community assembly processes

  13. Using Plant Functional Traits and Phylogenies to Understand Patterns of Plant Community Assembly in a Seasonal Tropical Forest in Lao PDR.

    Science.gov (United States)

    Satdichanh, Manichanh; Millet, Jérôme; Heinimann, Andreas; Nanthavong, Khamseng; Harrison, Rhett D

    2015-01-01

    Plant functional traits reflect different evolutionary responses to environmental variation, and among extant species determine the outcomes of interactions between plants and their environment, including other plant species. Thus, combining phylogenetic and trait-based information can be a powerful approach for understanding community assembly processes across a range of spatial scales. We used this approach to investigate tree community composition at Phou Khao Khouay National Park (18°14'-18°32'N; 102°38'- 102°59'E), Laos, where several distinct forest types occur in close proximity. The aim of our study was to examine patterns of plant community assembly across the strong environmental gradients evident at our site. We hypothesized that differences in tree community composition were being driven by an underlying gradient in soil conditions. Thus, we predicted that environmental filtering would predominate at the site and that the filtering would be strongest on sandier soil with low pH, as these are the conditions least favorable to plant growth. We surveyed eleven 0.25 ha (50x50 m) plots for all trees above 10 cm dbh (1221 individual trees, including 47 families, 70 genera and 123 species) and sampled soils in each plot. For each species in the community, we measured 11 commonly studied plant functional traits covering both the leaf and wood economic spectrum traits and we reconstructed a phylogenetic tree for 115 of the species in the community using rbcL and matK sequences downloaded from Genebank (other species were not available). Finally we compared the distribution of trait values and species at two scales (among plots and 10x10m subplots) to examine trait and phylogenetic community structures. Although there was strong evidence that an underlying soil gradient was determining patterns of species composition at the site, our results did not support the hypothesis that the environmental filtering dominated community assembly processes. For the

  14. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern

    International Nuclear Information System (INIS)

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT)

  15. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern

    Science.gov (United States)

    Bromley, Regina; Davey, Ross; Oliver, Lyn; Harvie, Rozelle; Baldock, Clive

    2006-08-01

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT).

  16. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern

    Energy Technology Data Exchange (ETDEWEB)

    Bromley, Regina [Northern Sydney Cancer Centre, Radiation Oncology, Royal North Shore Hospital, Sydney, NSW 2065 (Australia); Davey, Ross [Institute of Medical Physics, School of Physics, Sydney University, NSW 2006 (Australia); Oliver, Lyn [Northern Sydney Cancer Centre, Radiation Oncology, Royal North Shore Hospital, Sydney, NSW 2065 (Australia); Harvie, Rozelle [Institute of Medical Physics, School of Physics, Sydney University, NSW 2006 (Australia); Baldock, Clive [Bill Walsh Cancer Research Laboratories, Department of Medical Oncology, Royal North Shore Hospital, Sydney, NSW 2065 (Australia)

    2006-08-07

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT)

  17. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants

    OpenAIRE

    Julieta Benítez-Malvido; Wesley Dáttilo; Ana Paola Martínez-Falcón; César Durán-Barrón; Jorge Valenzuela**; Sara López; Rafael Lombera

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological ...

  18. CHARACTERIZATION OF LACTATE DEHYDROGENASE ISOZYME PATTERN AND MORPHOLOGY OF THREE MARINE FISH CELL LINES

    Institute of Scientific and Technical Information of China (English)

    郭华荣; 张士璀; 李红岩; 童裳亮; 相建海

    2002-01-01

    Three continuous marine fish cell lines of FG (i.e. , Flounder Gill) from flounder (Paralichthys olivaceus) gill, SPH (i.e., Sea Perch Heart) fro m sea perch (Lateolabrax japonicus) heart and RSBF (i.e., Red Sea Bream Fin) from red se a bream (Pagrosomus major) fin, were characterized by lactate dehydrogenase (LDH) is ozyme and morphological analysis. The LDH isozyme patterns of these three cell lines and their corresponding tissues of origin were investigated and compared. The results sho wed: (1) No difference was found in the LDH isozyme patterns of FG and flounder gill tissue. However, the LDH isozyme patterns of SPH and RSBF were significantly different from their cor responding tissues of origin; (2) LDH isozyme patterns of FG, SPH and RSBF were markedly di fferent from each other and could serve as genetic markers for species identification and de tection of cross contamination. Morphological change analysis of these three cell lines in compa rison to their original tissues indicated that FG cells still appeared epithelioid without mor phological transformation. However, morphological changes were found in SPH and RSBF compa red to their original tissues. Therefore, the cellular morphology was still plastic in the relatively stable culture conditions, and it was possible that change of LDH patterns was related to morphological changes of fish cells in vitro.

  19. The stem cell population of the human colon crypt: analysis via methylation patterns.

    Directory of Open Access Journals (Sweden)

    Pierre Nicolas

    2007-03-01

    Full Text Available The analysis of methylation patterns is a promising approach to investigate the genealogy of cell populations in an organism. In a stem cell-niche scenario, sampled methylation patterns are the stochastic outcome of a complex interplay between niche structural features such as the number of stem cells within a niche and the niche succession time, the methylation/demethylation process, and the randomness due to sampling. As a consequence, methylation pattern studies can reveal niche characteristics but also require appropriate statistical methods. The analysis of methylation patterns sampled from colon crypts is a prototype of such a study. Previous analyses were based on forward simulation of the cell content of the whole crypt and subsequent comparisons between simulated and experimental data using a few statistics as a proxy to summarize the data. In this paper we develop a more powerful method to analyze these data based on coalescent modelling and Bayesian inference. Results support a scenario where the colon crypt is maintained by a high number of stem cells; the posterior indicates a number greater than eight and the posterior mode is between 15 and 20. The results also provide further evidence for synergistic effects in the methylation/demethylation process that could for the first time be quantitatively assessed through their long-term consequences such as the coexistence of hypermethylated and hypomethylated patterns in the same colon crypt.

  20. Exocytosis and polarity in plant cells: insights by studying cellulose synthase complexes and the exocyst

    NARCIS (Netherlands)

    Ying Zhang, Ying

    2012-01-01

    The work presented in this thesis covers aspects of exocytosis, plant cell growth and cell wall formation. These processes are strongly linked as cell growth and cell wall formation occur simultaneously and exocytosis is the process that delivers cell wall components to the existing cell wall and in

  1. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season.

    Science.gov (United States)

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-02-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets. PMID:23467719

  2. Pattern formation in a spatial plant-wrack model with tide effect on the wrack

    OpenAIRE

    Sun, Gui-Quan; Li, Li; Jin, Zhen; Li, Bai-Lian

    2009-01-01

    Spatial patterns are a subfield of spatial ecology, and these patterns modify the temporal dynamics and stability properties of population densities at a range of spatial scales. Localized ecological interactions can generate striking large-scale spatial patterns in ecosystems through spatial self-organization. Possible mechanisms include oscillating consumer–resource interactions, localized disturbance–recovery processes, and scale-dependent feedback. However, in this paper, our main aim is ...

  3. Pattern of growth and 14C-assimilates distributions in relation to photosynthesis in radish plants treated with growth substances

    International Nuclear Information System (INIS)

    In a series of radish plants, with very thin hypocotyl and with a normal storage organ, the rates of photosynthesis, photorespiration and dark respiration did not differ. Therefore, the conclusion may be advanced, that translocation to the swollen hypocotyl is not determined by the photosynthetic productivity, but rather be the storage capacity. To check it this is connected with an unbalanced hormonal content, plants were treated with lanoline paste, with IAA, GA3, zeatin and all three in mixture or with injections of GA3-water solution into the swollen hypocotyl. In young radish plants, with high rate of growth of aerial parts, treatment with the above mentioned substances stimulated 14CO2-assimilation and increased retention of assimilates in 14C-donors, probably owing to retardation of their senescence. It increeased the competition for photosynthates between shoot and storage organ. In older plants, in the stage of accumulation of nutrients in the swollen hypocotyl, IAA + GA3 + zeatin did not affect 14CO2-assimilation; but in plants eated with growth regulators separately, assimilation decreased; IAA and GA3 stimulated transport and accumulation of labelled substances in the swollen hypocotyl. On the basis of experimental data the conclusion may be advanced that responsiveness of the particular organs and processes to growth regulators depends on the stage of plant development. Phytohormone did not change quantitatively the pattern 14C-assimilates distribution. They stimulated processes with preference for particular stages of development. (author)

  4. Pattern of growth and 14C-assimilates distributions in relation to photosynthesis in radish plants treated with growth substances

    Directory of Open Access Journals (Sweden)

    Z. Starck

    2015-05-01

    Full Text Available In a series of radish plants, with very thin hypocotyl and with a normal storage organ, the rates of photosynthesis, photorespiration and dark respiration did not differ. Therefore, the conclusion may be advanced, that translocation to the swollen hypocotyl is not determinated by the photosynthetic productivity, but rather the by storage capacity. To check it this is connected with an unbalanced hormonal content, plants were treated with lanoline paste, with IAA, GA3, zeatin and all three in mixture or with injections of GA3-water solution into the swollen hypocotyl. In young radish plants, with high rate of growth of aerial parts, treatment with the above mentioned substances stimulated 14CO2-assimilation and increased retention of assimilates in 14C-donors, probably owing to retardation of their senescence. It increased the competition for photosynthates between shoot and storage organ. In older plants, in the stage of accumulation of nutrients in the swollen hypocotyl, IAA +GA3+zeatin did not affect 14CO2-assimilation, but in plants treated with growth regulators separately, assimilation decreased; IAA and GA3 stimulated transport and accumulation of labelled substances in the swollen hypocotyl. On the basis of experimental data the conclusion may be advanced that responsiveness of the particular organs and processes to growth regulators depends on the stage of plant development. Phytohormone did not changed quantitatively the pattern of 14C-assimilates distribution. They stimulated processes with preference for particular stages of development.

  5. Nanobiotechnology meets plant cell biology: Carbon nanotubes as organelle targeting nanocarriers

    KAUST Repository

    Bayoumi, Maged Fouad

    2013-01-01

    For years, nanotechnology has shown great promise in the fields of biomedical and biotechnological sciences and medical research. In this review, we demonstrate its versatility and applicability in plant cell biology studies. Specifically, we discuss the ability of functionalized carbon nanotubes to penetrate the plant cell wall, target specific organelles, probe protein-carrier activity and induce organelle recycling in plant cells. We also, shed light on prospective applications of carbon nanomaterials in cell biology and plant cell transformation. © 2013 The Royal Society of Chemistry.

  6. The transition criteria of circulating flow pattern of moderator in the calandria tank of CANDU nuclear power plant

    International Nuclear Information System (INIS)

    The moderator cooling system to the Calandria tank of CANDU nuclear power plant provides an alternative pass of heat sink during the hypothetical loss of coolant accident. Also, the neutron population in the CANDU plant can be affected by the moderator temperature change which strongly depends on the circulating flow pattern in the Calandria tank. It has been known that there are three distinguished flow patterns: the buoyancy dominated flow, the momentum dominated flow, and the mixed type flow. The Canadian Nuclear Safety Commission (CNSC) recommended that a series of experimental works should be performed to verify the three dimensional codes. Two existing facilities, SPEL (1982) and STERN (1990), have produced experimental data for these purposes. The present work is also motivated to build up a new scaled experimental facility named HGU for the same purposes. CANDU-6 was selected as the target plant to be scaled down. In the design for the scaled facility, the knowledge on the flow regime transitions in the circulating flow was imperative. In the present study, to pave the way for the scaling, the flow pattern maps of circulating flow were constructed based on the Reynolds number and Archimedes number. The CFX code was employed with real meshes to represent all calandria tubes in the tank. The flow pattern maps were constructed for SPEL, STERN, HGU, and CANDU6. As the key transition criterion useful for scaling law, a new Archimedes number considering the jet impingement of the feed water in the Calandria tank was found. The transition of flow patterns was made with the same Archimedes number for CANDU6, STERN and HGU. However, SPEL which has third of the modified Archimedes number showed different maps in the wider region of mixed flow pattern was observed. It was found that the Archimedes number considering the inlet nozzle velocity plays the key role in patterns classification. Also, it can be suggested that the moderator cooling system needs to be designed

  7. NeuroArray: A Universal Interface for Patterning and Interrogating Neural Circuitry with Single Cell Resolution

    OpenAIRE

    Li, Wei; Xu, Zhen; Huang, Junzhe; Lin, Xudong; Luo, Rongcong; Chen, Chia-Hung; Shi, Peng

    2014-01-01

    Recreation of neural network in vitro with designed topology is a valuable tool to decipher how neurons behave when interacting in hierarchical networks. In this study, we developed a simple and effective platform to pattern primary neurons in array formats for interrogation of neural circuitry with single cell resolution. Unlike many surface-chemistry-based patterning methods, our NeuroArray technique is specially designed to accommodate neuron's polarized morphologies to make regular arrays...

  8. Co-culture of vascular endothelial cells and smooth muscle cells by hyaluronic acid micro-pattern on titanium surface

    Science.gov (United States)

    Li, Jingan; Li, Guicai; Zhang, Kun; Liao, Yuzhen; Yang, Ping; Maitz, Manfred F.; Huang, Nan

    2013-05-01

    Micro-patterning as an effective bio-modification technique is increasingly used in the development of biomaterials with superior mechanical and biological properties. However, as of now, little is known about the simultaneous regulation of endothelial cells (EC) and smooth muscle cells (SMC) by cardiovascular implants. In this study, a co-culture system of EC and SMC was built on titanium surface by the high molecular weight hyaluronic acid (HMW-HA) micro-pattern. Firstly, the micro-pattern sample with a geometry of 25 μm wide HMW-HA ridges, and 25 μm alkali-activated Ti grooves was prepared by microtransfer molding (μTM) for regulating SMC morphology. Secondly, hyaluronidase was used to decompose high molecular weight hyaluronic acid into low molecular weight hyaluronic acid which could promote EC adhesion. Finally, the morphology of the adherent EC was elongated by the SMC micro-pattern. The surface morphology of the patterned Ti was imaged by SEM. The existence of high molecular weight hyaluronic acid on the modified Ti surface was demonstrated by FTIR. The SMC micro-pattern and EC/SMC co-culture system were characterized by immunofluorescence microscopy. The nitric oxide release test and cell retention calculation were used to evaluate EC function on inhibiting hyperplasia and cell shedding, respectively. The results indicate that EC in EC/SMC co-culture system displayed a higher NO release and cell retention compared with EC cultured alone. It can be suggested that the EC/SMC co-culture system possessed superiority to EC cultured alone in inhibiting hyperplasia and cell shedding at least in a short time of 24 h.

  9. Influence of patterned topographic features on the formation of cardiac cell clusters and their rhythmic activities

    International Nuclear Information System (INIS)

    In conventional primary cultures, cardiac cells prepared from a newborn rat undergo spontaneous formation of cell clusters after several days. These cell clusters may be non-homogeneously distributed on a flat surface and show irregular beating which can be recorded by calcium ion imaging. In order to improve the cell cluster homogeneity and the beating regularity, patterned topographic features were used to guide the cellular growth and the cell layer formation. On the substrate with an array of broadly spaced cross features made of photoresist, cells grew on the places that were not occupied by the crosses and thus formed a cell layer with interconnected cell clusters. Accordingly, spatially coordinated regular beating could be recorded over the whole patterned area. In contrast, when cultured on the substrate with broadly spaced but inter-connected cross features, the cardiac cell layer showed beatings which were neither coordinated in space nor regular in time. Finally, when cultured on the substrate with narrowly spaced features, the cell beating became spatially coordinated but still remained irregular. Our results suggest a way to improve the rhythmic property of cultured cardiac cell layers which might be useful for further investigations. (paper)

  10. Sickle cell anemia in Brazil: personal, medical and endodontic patterns

    Directory of Open Access Journals (Sweden)

    Shirlene Barbosa Pimentel FERREIRA

    2016-01-01

    Full Text Available Abstract Sickle cell anemia (SCA is the most prevalent genetic disease worldwide. Recurrent vaso-occlusive infarcts predispose SCA patients to infections, which are the primary causes of morbidly and mortality. This study aimed to evaluate the relationship between SCA and endodontic diseases. Personal information, medical data (hematological indices, virologic testing, blood transfusions, medications received, splenectomy and information on the need for endodontic treatment were obtained from SCA patients who were registered and followed up by the Fundação Hemominas, Minas Gerais, Brazil.These data were compared with the need for root canal treatment in SCA patients. One hundred eight patients comprised the studied population, and the rate of the need for endodontic therapy was 10.2%. Among the medical data, a significant difference was observed for eosinophil (p = 0.045 counts and atypical lymphocyte counts (p = 0.036 when the groups (with and without the need for endodontic treatment were compared. Statistical relevance was observed when comparing the patients with and without the need for root canal therapy concerned eosinophil counts and atypical lymphocyte counts. The differences in statistical medical data, observed between the groups suggest that both parameters are naturally connected to the stimulation of the immune system that can occur in the presence of root canal infections and that can be harmful to SCA individuals.

  11. Differential DNA methylation patterns of homeobox genes in proximal and distal colon epithelial cells.

    Science.gov (United States)

    Barnicle, Alan; Seoighe, Cathal; Golden, Aaron; Greally, John M; Egan, Laurence J

    2016-04-01

    Region and cell-type specific differences in the molecular make up of colon epithelial cells have been reported. Those differences may underlie the region-specific characteristics of common colon epithelial diseases such as colorectal cancer and inflammatory bowel disease. DNA methylation is a cell-type specific epigenetic mark, essential for transcriptional regulation, silencing of repetitive DNA and genomic imprinting. Little is known about any region-specific variations in methylation patterns in human colon epithelial cells. Using purified epithelial cells and whole biopsies (n= 19) from human subjects, we generated epigenome-wide DNA methylation data (using the HELP-tagging assay), comparing the methylation signatures of the proximal and distal colon. We identified a total of 125 differentially methylated sites (DMS) mapping to transcription start sites of protein-coding genes, most notably several members of the homeobox (HOX) family of genes. Patterns of differential methylation were validated with MassArray EpiTYPER. We also examined DNA methylation in whole biopsies, applying a computational technique to deconvolve variation in methylation within cell types and variation in cell-type composition across biopsies. Including inferred epithelial proportions as a covariate in differential methylation analysis applied to the whole biopsies resulted in greater overlap with the results obtained from purified epithelial cells compared with when the covariate was not included. Results obtained from both approaches highlight region-specific methylation patterns ofHOXgenes in colonic epithelium. Regional variation in methylation patterns has implications for the study of diseases that exhibit regional expression patterns in the human colon, such as inflammatory bowel disease and colorectal cancer. PMID:26812987

  12. Patterning pallet arrays for cell selection based on high-resolution measurements of fluorescent biosensors.

    Science.gov (United States)

    Shadpour, Hamed; Zawistowski, Jon S; Herman, Annadele; Hahn, Klaus; Allbritton, Nancy L

    2011-06-24

    Pallet arrays enable cells to be separated while they remain adherent to a surface and provide a much greater range of cell selection criteria relative to that of current technologies. However there remains a need to further broaden cell selection criteria to include dynamic intracellular signaling events. To demonstrate the feasibility of measuring cellular protein behavior on the arrays using high resolution microscopy, the surfaces of individual pallets were modified to minimize the impact of scattered light at the pallet edges. The surfaces of the three-dimensional pallets on an array were patterned with a coating such as fibronectin using a customized stamping tool. Micropatterns of varying shape and size were printed in designated regions on the pallets in single or multiple steps to demonstrate the reliability and precision of patterning molecules on the pallet surface. Use of a fibronectin matrix stamped at the center of each pallet permitted the localization of H1299 and mouse embryonic fibroblast (MEF) cells to the pallet centers and away from the edges. Compared to pallet arrays with fibronectin coating the entire top surface, arrays with a central fibronectin pattern increased the percentage of cells localized to the pallet center by 3-4-fold. Localization of cells to the pallet center also enabled the physical separation of cells from optical artifacts created by the rough pallet side walls. To demonstrate the measurement of dynamic intracellular signaling on the arrays, fluorescence measurements of high spatial resolution were performed using a RhoA GTPase biosensor. This biosensor utilized fluorescence resonance energy transfer (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) to measure localized RhoA activity in cellular ruffles at the cell periphery. These results demonstrated the ability to perform spatially resolved measurements of fluorescence-based sensors on the pallet arrays. Thus, the patterned pallet arrays

  13. Systematic regional variations in Purkinje cell spiking patterns.

    Directory of Open Access Journals (Sweden)

    Jianqiang Xiao

    Full Text Available In contrast to the uniform anatomy of the cerebellar cortex, molecular and physiological studies indicate that significant differences exist between cortical regions, suggesting that the spiking activity of Purkinje cells (PCs in different regions could also show distinct characteristics. To investigate this possibility we obtained extracellular recordings from PCs in different zebrin bands in crus IIa and vermis lobules VIII and IX in anesthetized rats in order to compare PC firing characteristics between zebrin positive (Z+ and negative (Z- bands. In addition, we analyzed recordings from PCs in the A2 and C1 zones of several lobules in the posterior lobe, which largely contain Z+ and Z- PCs, respectively. In both datasets significant differences in simple spike (SS activity were observed between cortical regions. Specifically, Z- and C1 PCs had higher SS firing rates than Z+ and A2 PCs, respectively. The irregularity of SS firing (as assessed by measures of interspike interval distribution was greater in Z+ bands in both absolute and relative terms. The results regarding systematic variations in complex spike (CS activity were less consistent, suggesting that while real differences can exist, they may be sensitive to other factors than the cortical location of the PC. However, differences in the interactions between SSs and CSs, including the post-CS pause in SSs and post-pause modulation of SSs, were also consistently observed between bands. Similar, though less strong trends were observed in the zonal recordings. These systematic variations in spontaneous firing characteristics of PCs between zebrin bands in vivo, raises the possibility that fundamental differences in information encoding exist between cerebellar cortical regions.

  14. Aspects of plant cell growth and the actin cytoskeleton: lessons from root hairs

    NARCIS (Netherlands)

    Ruijter, de N.C.A.

    1999-01-01

    The main topic the thesis addresses is the role of the actin cytoskeleton in the growth process of plant cells. Plant growth implies a combination of cell division and cell expansion. The cytoskeleton, which exists of microtubules and actin filaments, plays a major role in both processes. Before cel

  15. Design of flow-field patterns for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Fuel cells are electrochemical devices that produce electricity at high efficiency without combustion. Fuel cells are emerging as viable candidates as power sources in many applications, including road vehicles, small-scale power stations, and possibly even portable electronics. This paper addresses the design of flow-field patterns for proton exchange membrane fuel cell (PEMFC). The PEMFC is a low-temperature fuel cell, in which a proton conductive polymer membrane is used as the electrolyte. In PEMFC, flow-field pattern is one important thing that effects the performance of PEMFC. This paper present three types of flow-field pattern that will be consider to be testing using CFD analysis and by experimental. The design look detail on to their shape and dimension to get the best pattern in term of more active electrode area compare to electrode area that will be used. Another advantage and disadvantage for these three type of flow-field patterns from literature also compared in this paper

  16. 3D patterned stem cell differentiation using thermo-responsive methylcellulose hydrogel molds

    Science.gov (United States)

    Lee, Wonjae; Park, Jon

    2016-07-01

    Tissue-specific patterned stem cell differentiation serves as the basis for the development, remodeling, and regeneration of the multicellular structure of the native tissues. We herein proposed a cytocompatible 3D casting process to recapitulate this patterned stem cell differentiation for reconstructing multicellular tissues in vitro. We first reconstituted the 2D culture conditions for stem cell fate control within 3D hydrogel by incorporating the sets of the diffusible signal molecules delivered through drug-releasing microparticles. Then, utilizing thermo-responsivity of methylcellulose (MC), we developed a cytocompatible casting process to mold these hydrogels into specific 3D configurations, generating the targeted spatial gradients of diffusible signal molecules. The liquid phase of the MC solution was viscous enough to adopt the shapes of 3D impression patterns, while the gelated MC served as a reliable mold for patterning the hydrogel prepolymers. When these patterned hydrogels were integrated together, the stem cells in each hydrogel distinctly differentiated toward individually defined fates, resulting in the formation of the multicellular tissue structure bearing the very structural integrity and characteristics as seen in vascularized bones and osteochondral tissues.

  17. 3D patterned stem cell differentiation using thermo-responsive methylcellulose hydrogel molds

    Science.gov (United States)

    Lee, Wonjae; Park, Jon

    2016-01-01

    Tissue-specific patterned stem cell differentiation serves as the basis for the development, remodeling, and regeneration of the multicellular structure of the native tissues. We herein proposed a cytocompatible 3D casting process to recapitulate this patterned stem cell differentiation for reconstructing multicellular tissues in vitro. We first reconstituted the 2D culture conditions for stem cell fate control within 3D hydrogel by incorporating the sets of the diffusible signal molecules delivered through drug-releasing microparticles. Then, utilizing thermo-responsivity of methylcellulose (MC), we developed a cytocompatible casting process to mold these hydrogels into specific 3D configurations, generating the targeted spatial gradients of diffusible signal molecules. The liquid phase of the MC solution was viscous enough to adopt the shapes of 3D impression patterns, while the gelated MC served as a reliable mold for patterning the hydrogel prepolymers. When these patterned hydrogels were integrated together, the stem cells in each hydrogel distinctly differentiated toward individually defined fates, resulting in the formation of the multicellular tissue structure bearing the very structural integrity and characteristics as seen in vascularized bones and osteochondral tissues. PMID:27381562

  18. Spontaneously immortalised bovine mammary epithelial cells exhibit a distinct gene expression pattern from the breast cancer cells

    Directory of Open Access Journals (Sweden)

    Li Qianqian

    2010-10-01

    Full Text Available Abstract Background Spontaneous immortalisation of cultured mammary epithelial cells (MECs is an extremely rare event, and the molecular mechanism behind spontaneous immortalisation of MECs is unclear. Here, we report the establishment of a spontaneously immortalised bovine mammary epithelial cell line (BME65Cs and the changes in gene expression associated with BME65Cs cells. Results BME65Cs cells maintain the general characteristics of normal mammary epithelial cells in morphology, karyotype and immunohistochemistry, and are accompanied by the activation of endogenous bTERT (bovine Telomerase Reverse Transcriptase and stabilisation of the telomere. Currently, BME65Cs cells have been passed for more than 220 generations, and these cells exhibit non-malignant transformation. The expression of multiple genes was investigated in BME65Cs cells, senescent BMECs (bovine MECs cells, early passage BMECs cells and MCF-7 cells (a human breast cancer cell line. In comparison with early passage BMECs cells, the expression of senescence-relevant apoptosis-related gene were significantly changed in BME65Cs cells. P16INK4a was downregulated, p53 was low expressed and Bax/Bcl-2 ratio was reversed. Moreover, a slight upregulation of the oncogene c-Myc, along with an undetectable level of breast tumor-related gene Bag-1 and TRPS-1, was observed in BME65Cs cells while these genes are all highly expressed in MCF-7. In addition, DNMT1 is upregulated in BME65Cs. These results suggest that the inhibition of both senescence and mitochondrial apoptosis signalling pathways contribute to the immortality of BME65Cs cells. The expression of p53 and p16INK4a in BME65Cs was altered in the pattern of down-regulation but not "loss", suggesting that this spontaneous immortalization is possibly initiated by other mechanism rather than gene mutation of p53 or p16INK4a. Conclusions Spontaneously immortalised BME65Cs cells maintain many characteristics of normal BMEC cells and

  19. Effect of Thai medicinal plant extracts on cell aggregation of Escherichia coli O157: H7.

    OpenAIRE

    Limsuwan, S.; Vanmanee, S.; Voravuthikunchai, S.

    2005-01-01

    Medicinal plants have been used for treating diarrhoea but the interference mechanisms are not clearly understood. One possible hypothesis is that of an effect on cell surface hydrophobicity of microbial cells. In this study, we examined cell aggregation affected by crude extracts of Thai medicinal plants on cell surface hydrophobicity of Escherichia coli strains by salt aggregation test. Correlation between minimal inhibitory concentration and cell aggregation was performed. Aqueous and etha...

  20. Determination of the pore size of cell walls of living plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Carpita, N.; Sabularse, D.; Montezinos, D.; Delmer, D.P.

    1979-09-14

    The limiting diameter of pores in the walls of living plant cells through which molecules can freely pass has been determined by a solute exclusion technique to be 35 to 38 angstroms for hair cells of Raphanus sativus roots and fibers of Gossypium hirsutum, 38 to 40 angstroms for cultured cells of Acer pseudoplatanus, and 45 to 52 angstroms for isolated palisade parenchyma cells of the leaves of Xanthium strumarium and Commelina communis. These results indicate that molecules with diameters larger than these pores would be restricted in their ability to penetrate such a cell wall, and that such a wall may represent a more significant barrier to cellular communication than has been previously assumed.

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

    Science.gov (United States)

    Cosgrove, D. J.

    1997-01-01

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

  2. Unleashing the potential of the root hair cell as a single plant cell type model in root systems biology

    OpenAIRE

    Zhenzhen eQiao; Marc eLibault

    2013-01-01

    Plant root is an organ composed of multiple cell types with different functions. This multicellular complexity limits our understanding of root biology because –omics studies performed at the level of the entire root reflect the average responses of all cells composing the organ. To overcome this difficulty and allow a more comprehensive understanding of root cell biology, an approach is needed that would focus on one single cell type in the plant root. Because of its biological functions (i....

  3. Quantitative tracking of tumor cells in phase-contrast microscopy exploiting halo artifact pattern

    Science.gov (United States)

    Kang, Mi-Sun; Song, Soo-Min; Lee, Hana; Kim, Myoung-Hee

    2012-03-01

    Tumor cell morphology is closely related to its invasiveness characteristics and migratory behaviors. An invasive tumor cell has a highly irregular shape, whereas a spherical cell is non-metastatic. Thus, quantitative analysis of cell features is crucial to determine tumor malignancy or to test the efficacy of anticancer treatment. We use phase-contrast microscopy to analyze single cell morphology and to monitor its change because it enables observation of long-term activity of living cells without photobleaching and phototoxicity, which is common in other fluorescence-labeled microscopy. Despite this advantage, there are image-level drawbacks to phase-contrast microscopy, such as local light effect and contrast interference ring, among others. Thus, we first applied a local filter to compensate for non-uniform illumination. Then, we used intensity distribution information to detect the cell boundary. In phase-contrast microscopy images, the cell normally appears as a dark region surrounded by a bright halo. As the halo artifact around the cell body is minimal and has an asymmetric diffusion pattern, we calculated the cross-sectional plane that intersected the center of each cell and was orthogonal to the first principal axis. Then, we extracted the dark cell region by level set. However, a dense population of cultured cells still rendered single-cell analysis difficult. Finally, we measured roundness and size to classify tumor cells into malignant and benign groups. We validated segmentation accuracy by comparing our findings with manually obtained results.

  4. Computational Modeling Reveals that a Combination of Chemotaxis and Differential Adhesion Leads to Robust Cell Sorting during Tissue Patterning

    OpenAIRE

    Tan, Rui Zhen; Chiam, Keng-Hwee

    2014-01-01

    Robust tissue patterning is crucial to many processes during development. The "French Flag" model of patterning, whereby naïve cells in a gradient of diffusible morphogen signal adopt different fates due to exposure to different amounts of morphogen concentration, has been the most widely proposed model for tissue patterning. However, recently, using time-lapse experiments, cell sorting has been found to be an alternative model for tissue patterning in the zebrafish neural tube. But it remain...

  5. Temporal protein expression pattern in intracellular signalling cascade during T-cell activation: a computational study.

    Science.gov (United States)

    Ganguli, Piyali; Chowdhury, Saikat; Bhowmick, Rupa; Sarkar, Ram Rup

    2015-10-01

    Various T-cell co-receptor molecules and calcium channel CRAC play a pivotal role in the maintenance of cell's functional responses by regulating the production of effector molecules (mostly cytokines) that aids in immune clearance and also maintaining the cell in a functionally active state. Any defect in these co-receptor signalling pathways may lead to an altered expression pattern of the effector molecules. To study the propagation of such defects with time and their effect on the intracellular protein expression patterns, a comprehensive and largest pathway map of T-cell activation network is reconstructed manually. The entire pathway reactions are then translated using logical equations and simulated using the published time series microarray expression data as inputs. After validating the model, the effect of in silico knock down of co-receptor molecules on the expression patterns of their downstream proteins is studied and simultaneously the changes in the phenotypic behaviours of the T-cell population are predicted, which shows significant variations among the proteins expression and the signalling routes through which the response is propagated in the cytoplasm. This integrative computational approach serves as a valuable technique to study the changes in protein expression patterns and helps to predict variations in the cellular behaviour. PMID:26564978

  6. Probing neural cell behaviors through micro-/nano-patterned chitosan substrates.

    Science.gov (United States)

    Sung, Chun-Yen; Yang, Chung-Yao; Chen, Wen-Shiang; Wang, Yang-Kao; Yeh, J Andrew; Cheng, Chao-Min

    2015-12-01

    In this study, we describe the development of surface-modified chitosan substrates to examine topographically related Neuro-2a cell behaviors. Different functional groups can be modified on chitosan surfaces to probe Neuro-2a cell morphology. To prepare chitosan substrates with micro/nano-scaled features, we demonstrated an easy-to-handle method that combined photolithography, inductively coupled plasma reactive ion etching, Ag nanoparticle-assisted etching, and solution casting. The results show that Neuro-2a cells preferred to adhere to a flat chitosan surface rather than a nanotextured chitosan surface as evidenced by greater immobilization and differentiation, suggesting that surface topography is crucial for neural patterning. In addition, we developed chitosan substrates with different geometric patterns and flat region depth; this allowed us to re-arrange or re-pattern Neuro-2a cell colonies at desired locations. We found that a polarity-induced micropattern provided the most suitable surface pattern for promoting neural network formation on a chitosan substrate. The cellular polarity of single Neuro-2a cell spreading correlated to a diamond-like geometry and neurite outgrowth was induced from the corners toward the grooves of the structures. This study provide greater insight into neurobiology, including neurotransmitter screening, electrophysiological stimulation platforms, and biomedical engineering. PMID:26685015

  7. Selective deposition contact patterning using atomic layer deposition for the fabrication of crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Selective deposition contact (SDC) patterning was applied to fabricate the rear side passivation of crystalline silicon (Si) solar cells. By this method, using screen printing for contact patterning and atomic layer deposition for the passivation of Si solar cells with Al2O3, we produced local contacts without photolithography or any laser-based processes. Passivated emitter and rear-contact solar cells passivated with ozone-based Al2O3 showed, for the SDC process, an up-to-0.7% absolute conversion-efficiency improvement. The results of this experiment indicate that the proposed method is feasible for conversion-efficiency improvement of industrial crystalline Si solar cells. - Highlights: • We propose a local contact formation process. • Local contact forms a screen print and an atomic layer deposited-Al2O3 film. • Ozone-based Al2O3 thin film was selectively deposited onto patterned silicon. • Selective deposition contact patterning method can increase cell-efficiency by 0.7%

  8. Cytotoxicity of Selected Medicinal and Nonmedicinal Plant Extracts to Microbial and Cervical Cancer Cells

    OpenAIRE

    Gary M. Booth; Malmstrom, Robert D.; Erica Kipp; Alexandra Paul

    2012-01-01

    This study investigated the cytotoxicity of 55 species of plants. Each plant was rated as medicinal, or nonmedicinal based on the existing literature. About 79% of the medicinal plants showed some cytotoxicity, while 75% of the nonmedicinal plants showed bioactivity. It appears that Asteraceae, Labiatae, Pinaceae, and Chenopodiaceae were particularly active against human cervical cancer cells. Based on the literature, only three of the 55 plants have been significantly investigated for cytoto...

  9. Are invasive plants more competitive than native conspecifics? Patterns vary with competitors

    Science.gov (United States)

    Zheng, Yulong; Feng, Yulong; Valiente-Banuet, Alfonso; Li, Yangping; Liao, Zhiyong; Zhang, Jiaolin; Chen, Yajun

    2015-10-01

    Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies [‘Evolution of Increased Competitive Ability’ (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges competed directly, and competed with native residents from both invasive (China) and native (Mexico) ranges respectively. Invasive A. adenophora plants were more competitive than their conspecifics from native populations when competing with natives from China (interspecific competition), but not when competing with natives from Mexico. Invasive A. adenophora plants also showed higher competitive ability when grown in high-density monoculture communities of plants from the same population (intrapopulation competition). In contrast, invasive A. adenophora plants showed lower competitive ability when competing with plants from native populations (intraspecific competition). Our results indicated that in the invasive range A. adenophora has evolved to effectively cope with co-occurring natives and high density environments, contributing to invasion success. Here, we showed the significant effects of competitors, which should be considered carefully when testing the EICA hypothesis.

  10. Diversity of beetle genes encoding novel plant cell wall degrading enzymes

    OpenAIRE

    Pauchet, Y.; Wilkinson, P.; Chauhan, R.; Ffrench-Constant, R.

    2010-01-01

    Plant cell walls are a heterogeneous mixture of polysaccharides and proteins that require a range of different enzymes to degrade them. Plant cell walls are also the primary source of cellulose, the most abundant and useful biopolymer on the planet. Plant cell wall degrading enzymes (PCWDEs) are therefore important in a wide range of biotechnological processes from the production of biofuels and food to waste processing. However, despite the fact that the last common ancestor of all deuterost...

  11. Deciphering the roles of acyl-CoA-binding proteins in plant cells.

    Science.gov (United States)

    Lung, Shiu-Cheung; Chye, Mee-Len

    2016-09-01

    Lipid trafficking is vital for metabolite exchange and signal communications between organelles and endomembranes. Acyl-CoA-binding proteins (ACBPs) are involved in the intracellular transport, protection, and pool formation of acyl-CoA esters, which are important intermediates and regulators in lipid metabolism and cellular signaling. In this review, we highlight recent advances in our understanding of plant ACBP families from a cellular and developmental perspective. Plant ACBPs have been extensively studied in Arabidopsis thaliana (a dicot) and to a lesser extent in Oryza sativa (a monocot). Thus far, they have been detected in the plasma membrane, vesicles, endoplasmic reticulum, Golgi apparatus, apoplast, cytosol, nuclear periphery, and peroxisomes. In combination with biochemical and molecular genetic tools, the widespread subcellular distribution of respective ACBP members has been explicitly linked to their functions in lipid metabolism during development and in response to stresses. At the cellular level, strong expression of specific ACBP homologs in specialized cells, such as embryos, stem epidermis, guard cells, male gametophytes, and phloem sap, is of relevance to their corresponding distinct roles in organ development and stress responses. Other interesting patterns in their subcellular localization and spatial expression that prompt new directions in future investigations are discussed. PMID:26340904

  12. Molecular Stratification of Clear Cell Renal Cell Carcinoma by Consensus Clustering Reveals Distinct Subtypes and Survival Patterns

    OpenAIRE

    Brannon, A. Rose; Reddy, Anupama; Seiler, Michael; Arreola, Alexandra; Moore, Dominic T.; Pruthi, Raj S.; Wallen, Eric M.; Nielsen, Matthew E; Liu, Huiqing; Nathanson, Katherine L.; Ljungberg, Börje; Zhao, Hongjuan; BROOKS, JAMES D.; Ganesan, Shridar; Bhanot, Gyan

    2010-01-01

    Clear cell renal cell carcinoma (ccRCC) is the predominant RCC subtype, but even within this classification, the natural history is heterogeneous and difficult to predict. A sophisticated understanding of the molecular features most discriminatory for the underlying tumor heterogeneity should be predicated on identifiable and biologically meaningful patterns of gene expression. Gene expression microarray data were analyzed using software that implements iterative unsupervised consensus cluste...

  13. Effect of Land Use Pattern on Mineralization of Residual C and N from Plant Materials Decomposing Under Field Conditions

    Institute of Scientific and Technical Information of China (English)

    CHENGLILI; WENQIXIAO

    1998-01-01

    Four kinds of plant materials(astragalus,azolla,rice straw and water hyacinth) were allowed to decom-pose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions.Greater amounts of C and N from azolla were retained in soils throughout the 10-year experi-mental period compared to those from the other plant materials.The residual C of all the plant materials in the two soils under upland conditions mineralized at rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for those under submerge conditions were between 6.5-13.1 years,Minera-liztion of residual organic N followed the same pattern as residual C.Compared to residual C,however,the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N retained in soils were higher.More N from plant materials was retained in the yellow-brown soil than in the red soil,but no consistent differences in the amounts of C from plant materials and in the mineraliztion rates of both residual C and residual organic N between the wto soils could be folund.

  14. Different concentrations of berberine result in distinct cellular localization patterns and cell cycle effects in a melanoma cell line

    OpenAIRE

    Serafim, Teresa; Oliveira, Paulo; Sardao, Vilma; Perkins, Ed; Parke, Donna; Holy, Jon

    2008-01-01

    Abstract Purpose Natural products represent a rich reservoir of potential small molecule inhibitors exhibiting antiproliferative and tumoricidal properties. An example is the isoquinoline alkaloid berberine, which is found in plants such as goldenseal (Hydrastis canadensis). Studies have shown that berberine is able to trigger apoptosis in different malignant cell lines, and can also lead to cell cycle arrest at sub-apoptotic doses. A particularly interesting feature of berberine is the fact...

  15. Modeling photovoltaic performance in periodic patterned colloidal quantum dot solar cells.

    Science.gov (United States)

    Fu, Yulan; Dinku, Abay G; Hara, Yukihiro; Miller, Christopher W; Vrouwenvelder, Kristina T; Lopez, Rene

    2015-07-27

    Colloidal quantum dot (CQD) solar cells have attracted tremendous attention mostly due to their wide absorption spectrum window and potentially low processability cost. The ultimate efficiency of CQD solar cells is highly limited by their high trap state density. Here we show that the overall device power conversion efficiency could be improved by employing photonic structures that enhance both charge generation and collection efficiencies. By employing a two-dimensional numerical model, we have calculated the characteristics of patterned CQD solar cells based of a simple grating structure. Our calculation predicts a power conversion efficiency as high as 11.2%, with a short circuit current density of 35.2 mA/cm2, a value nearly 1.5 times larger than the conventional flat design, showing the great potential value of patterned quantum dot solar cells. PMID:26367680

  16. Monitoring programmed cell death of living plant tissues in microfluidics using electrochemical and optical techniques

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Svensson, Birte; Emnéus, Jenny; Dufva, Martin; Finnie, Christine

    optically detectable events during PCD in barley aleurone layer, a cell model for living plant tissues, for a better understanding of the underlying mechanisms of PCD in plants. Microfluidic cell culture enables in vitro experiments to approach in vivo conditions. The major advantage of electrochemical...... importance, since it is known that reactive oxygen species, which are affected by changes in the redox activity of the cells3, are involved in PCD in plants, but the relationship between and mechanisms behind ROS and PCD is only poorly understood in plant cells4. Recently, it has been shown, using optical...

  17. Predicting plant diversity patterns in Madagascar: understanding the effects of climate and land cover change in a biodiversity hotspot.

    Directory of Open Access Journals (Sweden)

    Kerry A Brown

    Full Text Available Climate and land cover change are driving a major reorganization of terrestrial biotic communities in tropical ecosystems. In an effort to understand how biodiversity patterns in the tropics will respond to individual and combined effects of these two drivers of environmental change, we use species distribution models (SDMs calibrated for recent climate and land cover variables and projected to future scenarios to predict changes in diversity patterns in Madagascar. We collected occurrence records for 828 plant genera and 2186 plant species. We developed three scenarios, (i.e., climate only, land cover only and combined climate-land cover based on recent and future climate and land cover variables. We used this modelling framework to investigate how the impacts of changes to climate and land cover influenced biodiversity across ecoregions and elevation bands. There were large-scale climate- and land cover-driven changes in plant biodiversity across Madagascar, including both losses and gains in diversity. The sharpest declines in biodiversity were projected for the eastern escarpment and high elevation ecosystems. Sharp declines in diversity were driven by the combined climate-land cover scenarios; however, there were subtle, region-specific differences in model outputs for each scenario, where certain regions experienced relatively higher species loss under climate or land cover only models. We strongly caution that predicted future gains in plant diversity will depend on the development and maintenance of dispersal pathways that connect current and future suitable habitats. The forecast for Madagascar's plant diversity in the face of future environmental change is worrying: regional diversity will continue to decrease in response to the combined effects of climate and land cover change, with habitats such as ericoid thickets and eastern lowland and sub-humid forests particularly vulnerable into the future.

  18. Roles of the plasma membrane and the cell wall in the responses of plant cells to freezing.

    Science.gov (United States)

    Yamada, Tomoyoshi; Kuroda, Katsushi; Jitsuyama, Yutaka; Takezawa, Daisuke; Arakawa, Keita; Fujikawa, Seizo

    2002-09-01

    In an effort to clarify the responses of a wide range of plant cells to freezing, we examined the responses to freezing of the cells of chilling-sensitive and chilling-resistant tropical and subtropical plants. Among the cells of the plants that we examined, those of African violet ( Saintpaulia grotei Engl.) leaves were most chilling-sensitive, those of hypocotyls in mungbean [ Vigna radiata (L.) R. Wilcz.] seedlings were moderately chilling-sensitive, and those of orchid [ Paphiopedilum insigne (Wallich ex Lindl.) Pfitz.] leaves were chilling-resistant, when all were chilled at -2 degrees C. By contrast, all these plant cells were freezing-sensitive and suffered extensive damage when they were frozen at -2 degrees C. Cryo-scanning electron microscopy (Cryo-SEM) confirmed that, upon chilling at -2 degrees C, both chilling-sensitive and chilling-resistant plant cells were supercooled. Upon freezing at -2 degrees C, by contrast, intracellular freezing occurred in Saintpaulia leaf cells, frost plasmolysis followed by intracellular freezing occurred in mungbean seedling cells, and extracellular freezing (cytorrhysis) occurred in orchid leaf cells. We postulate that chilling-related destabilization of membranes might result in the loss of the ability of the plasma membrane to act as a barrier against the propagation of extracellular ice in chilling-sensitive plant cells. We also examined the role of cell walls in the response to freezing using cells in which the plasma membrane had been disrupted by repeated freezing and thawing. In chilling-sensitive Saintpaulia and mungbean cells, the cells with a disrupted plasma membrane responded to freezing at -2 degrees C by intracellular freezing. By contrast, in chilling-resistant orchid cells, as well as in other cells of chilling-resistant and freezing-resistant plant tissues, including leaves of orchard grass ( Dactylis glomerata L.), leaves of Arabidopsis thaliana (L.) Heynh. and cortical tissues of mulberry ( Morus

  19. Patterns of species diversity and phylogenetic structure of vascular plants on the Qinghai-Tibetan Plateau

    OpenAIRE

    Yan, Yujing; Yang, Xian; Tang, Zhiyao

    2013-01-01

    Large-scale patterns of species richness and the underlying mechanisms regulating these patterns have long been the central issues in biogeography and macroecology. Phylogenetic community structure is a result of combined effects of contemporary ecological interactions, environmental filtering, and evolutionary history, and it links community ecology with biogeography and trait evolution. The Qinghai-Tibetan Plateau provides a good opportunity to test the influence of contemporary climate on ...

  20. Biodiversity Status, Distribution and Use Pattern of Some Ethno-Medicinal Plants

    Directory of Open Access Journals (Sweden)

    Priti KUMARI

    2012-12-01

    Full Text Available The erosion of plant biodiversity is a matter of global concern. Due to unawareness the building blocks of entire ecosystems are disappearing. Some medicinal plants like Taxus baccata Linn., Thymus serpyllum Linn., Coleus forskohli Will., Oroxylum indicum Linn., Valeriana hardwickii Wall., Malaxis acuminata D.Don, Habenaria edgeworthii Hook. f.ex.Collett., Costus speciosus (Koen. Sm., Dioscorea deltodea Wall., Gloriosa superba Linn., Polygonatum cirrhifolium Wall. and Polygonatum verticillatum Linn., Thalictrum foliolosum DC., Berberis aristata DC., Baliospermum montanum Will., Bergenia ciliata (Haworth Sternb., Clerodendrum serratum Linn., Valeriana jatamansii Jones, Celastrus paniculatus Will., Habenaria intermedeia D. Don, and Curculigo orchioides Gaerth are reached on the border of extinction. The 2008 IUCN Red List shows that the number of threatened plant species is increasing gradually (IUCN 2008. Therefore, there is an immediate need for conservation steps to be taken up along with promotion of conservation of medicinal plants.

  1. The effect of isolation and history on colonization patterns of plant species in secondary woodland

    NARCIS (Netherlands)

    Grashof-Bokdam, C.J.; Geertsema, W.

    1998-01-01

    Colonization success of woodland originating after 1850 was determined for seventeen forest plant species having different dispersal strategies. Colonization rate of the studied endo- and exozoochorous species apparently was considerable higher than that of species having short distance dispersal li

  2. Balancing High-Load Scenarios with Next Cell Predictions and Mobility Pattern Recognition

    OpenAIRE

    Michaelis, Stefan

    2012-01-01

    Knowing where a mobile user will be next can deliver a tremendous increase in network performance under high load, as this knowledge enables pro-active load balancing. To derive this information, sequences of traversed cells are fed into pattern detection algorithms. After the training phase the learned model predicts each user’s next cell. Even for complex scenarios, the prediction accuracy can exceed 90%. Predictions are used to rearrange mobile connections in a simulat...

  3. Control of spatial cell attachment on carbon nanofiber patterns on polycarbonate urethane

    OpenAIRE

    Bajaj, Piyush; Khang, Dongwoo; Webster, Thomas J

    2006-01-01

    A highly aligned pattern of carbon nanofibers (CNF) on polycarbonate urethane (PCU) for tissue engineering applications was created by placing a CNF–ethanol solution in 30μm width copper grid grooves on top of PCU. In vitro results provided the first evidence that fibroblasts and vascular smooth muscle cells selectively adhered to the PCU regions. However, endothelial cells did not display a preference for adhesion to the CNF compared with PCU regions. Previous studies have shown selective ad...

  4. Variable stretch pattern enhances surfactant secretion in alveolar type II cells in culture

    OpenAIRE

    Arold, Stephen P.; Bartolák-Suki, Erzsébet; Suki, Béla

    2009-01-01

    Secretion of pulmonary surfactant that maintains low surface tension within the lung is primarily mediated by mechanical stretching of alveolar epithelial type II (AEII) cells. We have shown that guinea pigs ventilated with random variations in frequency and tidal volume had significantly larger pools of surfactant in the lung than animals ventilated in a monotonous manner. Here, we test the hypothesis that variable stretch patterns imparted on the AEII cells results in enhanced surfactant se...

  5. Development of a High-Throughput Functional Screen Using Nanowell-Assisted Cell Patterning.

    Science.gov (United States)

    Ozkumur, Ayca Yalcin; Goods, Brittany A; Love, J Christopher

    2015-09-01

    Living-cell-based screens can facilitate lead discovery of functional therapeutics of interest. A versatile and scalable method is reported that uses dense arrays of nanowells for imparting defined patterns on monolayers of cells. It is shown that this approach can coordinate a multi-component biological assay by designing and implementing a high-throughput, functional nanoliter-scale neutralization assay to identify neutralizing antibodies against HIV. PMID:26121321

  6. Localisation pattern of Foxp3+ regulatory T cells is associated with clinical behaviour in gastric cancer

    OpenAIRE

    Mizukami, Y.; Kono, K; Kawaguchi, Y; Akaike, H.; Kamimura, K.; Sugai, H.; Fujii, H.

    2007-01-01

    It has been reported that the population of regulatory T cells (T regs) is increased in tumour-infiltrating lymphocytes in cancer-bearing hosts. Recently, forkhead/winged helix transcription factor p3, Foxp3, is thought to be the most reliable marker of T regs. In the present study, we investigated the prevalence and localisation pattern of Foxp3+ cells in gastric cancer (n=80) by immunohistochemistry, in relation to the clinical outcome of gastric cancer patients. Immunohistochemical stainin...

  7. Spatial patterns of ephemeral plants in Gurbantünggüt Desert

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the present research, the authors measured parameters of richness, cover and importance value of ephemeral and ephemeroid plants on south-north and east-west transects in the Gurbantünggüt Desert in early spring, and investigated and analyzed the microhabitats, such as terrain, geomorphology, soil physical-chemical properties and crusts. By comparison, the regional differences in the ephemeral distribution in the desert were revealed. The species of ephemeral plants in the south and center are the richest and those in the west are the poorest in the desert. The cover of ephemeral plants in the mid-south is higher than that in the north, and that in the mid-east is higher than that in the west. The response of ephemeral plants to the spatial variation of the desert habitat forms the population-habitat gradient of ephemeral plants. The characteristics are: (1) In the habitat with higher terrain, coarser textured soil with poorer sorting and correspondingly higher organic matter and lower alkali-saline contents, Carex physoides and Eremopyrum orientale are the dominant ephemeral plants; (2) In the dry habitat with lower terrain, looser textured soil, some organic matter, alkali-saline soil, and developed crust, the ephemeral plants Alyssum linifolium and Erodium oxyrrhynchum are of characteristic of drought and alkali-saline tolerance; (3) In the habitat with lower terrain, some water and more alkali-saline soil, the ephemeral plants Neotorularia torulosa and Hypecoum parviflorum being of alkali-saline tolerance are mainly developed. However, most ephemerals are distributed in a habitat order of higher terrain, some organic, and less alkali-saline soil on the above-mentioned ephemeral population-habitat gradient. The spatial gradient of variation in desert microhabitats is small, and as a whole, the physiological character of mesophytism is represented by the desert ephemerals.

  8. Are invasive plants more competitive than native conspecifics? Patterns vary with competitors

    OpenAIRE

    Yulong Zheng; Yulong Feng; Alfonso Valiente-Banuet; Yangping Li; Zhiyong Liao; Jiaolin Zhang; Yajun Chen

    2015-01-01

    Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies [‘Evolution of Increased Competitive Ability’ (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges compete...

  9. Biodiversity Status, Distribution and Use Pattern of Some Ethno-Medicinal Plants

    OpenAIRE

    Kumari, Priti; Joshi, Girish Chandra; Lalit Mohan TEWARI

    2012-01-01

    The erosion of plant biodiversity is a matter of global concern. Due to unawareness the building blocks of entire ecosystems are disappearing. Some medicinal plants like Taxus baccata Linn., Thymus serpyllum Linn., Coleus forskohli Will., Oroxylum indicum Linn., Valeriana hardwickii Wall., Malaxis acuminata D.Don, Habenaria edgeworthii Hook. f.ex.Collett., Costus speciosus (Koen.) Sm., Dioscorea deltodea Wall., Gloriosa superba Linn., Polygonatum cirrhifolium Wall. and Polygonatum verticilla...

  10. Xylem conduits of a resurrection plant contain a unique lipid lining and refill following a distinct pattern after desiccation.

    Science.gov (United States)

    Wagner, H J; Schneider, H; Mimietz, S; Wistuba, N; Rokitta, M; Krohne, G; Haase, A; Zimmermann, U

    2000-11-01

    The axial and radial refilling with water of cut dry branches (up to 80 cm tall) of the resurrection plant Myrothamnus flabellifolia was studied in both acro- and basipetal directions by using 1H-NMR imaging. NMR measurements showed that the conducting elements were not filled simultaneously. Axial water ascent occurred initially only in a cluster of a very few conducting elements. Refilling of the other conducting elements and of the living cells was mainly achieved by radial extraction of water from these initial conducting elements. With time, xylem elements in a few further regions were apparently refilled axially. Radial water spread through the tissue occurred almost linearly with time, but much faster in the acropetal than in the basipetal direction. Application of hydrostatic pressure (up to 16 kPa) produced similar temporal and spatial radial refilling patterns, except that more conducting elements were refilled axially during the first phase of water rise. The addition of raffinose to the water considerably reduced axial and radial spreading rates. The polarity of water climbing was supported by measurements of the water rise in dry branches using the 'light refraction'(and, sometimes, the 'leaf recurving') method. Basipetal refilling of the xylem conduit exhibited biphasic kinetics; the final rise height did not exceed 20-30 cm. Three-cm-long branch pieces also showed a directionality of water climbing, ruling out the possibility that changes in the conducting area from the base to the apex of the branches were responsible for this effect. The polarity of water ascent was independent of gravity and also did not change when the ambient temperature was raised to c. 40 degrees C. At external pressures of 50-100 kPa the polarity disappeared, with basipetal and acropetal refill times of the xylem conduit of tall branches becoming comparable. Refilling of branches dried horizontally (with a clinostat) or inverted (in the direction of gravity) showed a

  11. Floristic analysis and distribution pattern of alien plants in Shandong Province,eastern China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Alien plants,along with their ecological invasion and negative impacts on indigenous species diversity and ecosystems,are one of the major topics of current ecological research.The background investigation and floristic analysis of alien plants are very important and form an essential database for invasive species research,control and management.In our study these alien plants,mainly collected from the Flora of Shandong Province,combined with a field survey,were studied and analyzed.We also established a floristic database.Our findings are as follows:1) there are a total of 827 alien species,belonging to 122 families and 416 genera of which 348 species were imported from other countries;2) a high proportion,39.0% of the flora in Shandong Province,is accounted for by alien species,of which 21 dominant families largely belong to the Rosaceae,Leguminosae,Asteraceae and Gramineae;3) the diverse geographical distribution of the genera is characterized by species dominant in the temperate zone which accounts for 52.5% of the alien plants and 44.1% of the plants from the tropics;4) the origins of alien species and their centralized distribution in Shandong together show the anthropogenic effect and unnatural impacts on the environment and 5) in Shandong Province,alien plants originate more from temperate zones than from any other areas of the world.

  12. A distribution pattern of cadmium, gadolinium and samarium in Phaseolus vulgaris (L) plants as assessed by dynamic neutron radiography

    International Nuclear Information System (INIS)

    The qualitative and semi-quantitative distributions, presumably apoplast transport patterns for the Gd, Sm and Cd were investigated in the primordial leaf tissues of the bean using dynamic neutron radiography. According to the applied 3D, 2D images and the pixel count distribution histograms of the considered gray levels, peculiar distribution patterns were postulated for the elements. Main and lateral vascular systems for Gd, the cell walls as well as intercellular spaces for Sm and the main leaf vein for Cd assumed to be the apoplast transport spaces and volumes

  13. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    Science.gov (United States)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  14. Co-infection patterns and geographic distribution of a complex pathosystem targeted by pathogen-resistant plants.

    Science.gov (United States)

    Biddle, J M; Linde, C; Godfree, R C

    2012-01-01

    Increasingly, pathogen-resistant (PR) plants are being developed to reduce the agricultural impacts of disease. However PR plants also have the potential to result in increased invasiveness of nontarget host populations and so pose a potential threat to nontarget ecosystems. In this paper we use a new framework to investigate geographical variation in the potential risk associated with unintended release of genetically modified alfalfa mosaic virus (AMV)-resistant Trifolium repens (white clover) into nontarget host populations containing AMV, clover yellow vein virus (ClYVV), and white clover mosaic virus (WCIMV) in southeastern Australia. Surveys of 213 sites in 37 habitat types over a 300 000-km2 study region showed that T. repens is a significant weed of many high-conservation-value habitats in southeastern Australia and that AMV, ClYVV, and WClMV occur in 15-97% of nontarget host populations. However, T. repens abundance varied with site disturbance, habitat conservation value, and proximity to cropping, and all viral pathogens had distinct geographic distributions and infection patterns. Virus species frequently co-infected host plants and displayed nonindependent distributions within host populations, although co-infection patterns varied across the study region. Our results clearly illustrate the complexity of conducting environmental risk assessments that involve geographically widespread, invasive pasture species and demonstrate the general need for targeted, habitat- and pathosystem-specific studies prior to the process of tiered risk assessment. PMID:22471074

  15. Patterns of DNA damage response in intracranial germ cell tumors versus glioblastomas reflect cell of origin rather than brain environment

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Hoei-Hansen, Christina E; Krizova, Katerina; Hamerlik, Petra; Skakkebæk, Niels E; Rajpert-De Meyts, Ewa; Bartek, Jiri

    2014-01-01

    were no clear aberrations in the ATM-Chk2-p53 pathway components among the PIGCT cohort; iii) Subsets of PIGCTs showed unusual cytosolic localization of Chk2 and/or ATM. Collectively, these results show that PIGCTs mimic the DDR activation patterns of their gonadal germ cell tumor counterparts, rather......The DNA damage response (DDR) machinery becomes commonly activated in response to oncogenes and during early stages of development of solid malignancies, with an exception of testicular germ cell tumors (TGCTs). The active DDR signaling evokes cell death or senescence but this anti-tumor barrier...... cell tumors (PIGCTs), to address the roles of cell-intrinsic factors including cell of origin, versus local tissue environment, in the constitutive DDR activation in vivo. Immunohistochemical analysis of 7 biomarkers on a series of 21 PIGCTs (germinomas and other subtypes), 20 normal brain specimens...

  16. Involvement of Plant Stem Cells or Stem Cell-Like Cells in Dedifferentiation

    OpenAIRE

    Jiang, Fangwei; Feng, Zhenhua; Liu, Hailiang; Zhu, Jian

    2015-01-01

    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 pro...

  17. Integration of plasma-assisted surface chemical modification, soft lithography, and protein surface activation for single-cell patterning

    Science.gov (United States)

    Cheng, Q.; Komvopoulos, K.

    2010-07-01

    Surface patterning for single-cell culture was accomplished by combining plasma-assisted surface chemical modification, soft lithography, and protein-induced surface activation. Hydrophilic patterns were produced on Parylene C films deposited on glass substrates by oxygen plasma treatment through the windows of polydimethylsiloxane shadow masks. After incubation first with Pluronic F108 solution and then serum medium overnight, surface seeding with mesenchymal stem cells in serum medium resulted in single-cell patterning. The present method provides a means of surface patterning with direct implications in single-cell culture.

  18. Non-invasive imaging of cellulose microfibril orientation within plant cell walls by polarized Raman microspectroscopy.

    Science.gov (United States)

    Sun, Lan; Singh, Seema; Joo, Michael; Vega-Sanchez, Miguel; Ronald, Pamela; Simmons, Blake A; Adams, Paul; Auer, Manfred

    2016-01-01

    Cellulose microfibrils represent the major scaffold of plant cell walls. Different packing and orientation of the microfibrils at the microscopic scale determines the macroscopic properties of cell walls and thus affect their functions with a profound effect on plant survival. We developed a polarized Raman microspectroscopic method to determine cellulose microfibril orientation within rice plant cell walls. Employing an array of point measurements as well as area imaging and subsequent Matlab-assisted data processing, we were able to characterize the distribution of cellulose microfibril orientation in terms of director angle and anisotropy magnitude. Using this approach we detected differences between wild type rice plants and the rice brittle culm mutant, which shows a more disordered cellulose microfibril arrangement, and differences between different tissues of a wild type rice plant. This novel non-invasive Raman imaging approach allows for quantitative assessment of cellulose fiber orientation in cell walls of herbaceous plants, an important advancement in cell wall characterization. PMID:26137889

  19. The Plant Short-Chain Dehydrogenase (SDR superfamily: genome-wide inventory and diversification patterns

    Directory of Open Access Journals (Sweden)

    Moummou Hanane

    2012-11-01

    Full Text Available Abstract Background Short-chain dehydrogenases/reductases (SDRs form one of the largest and oldest NAD(P(H dependent oxidoreductase families. Despite a conserved ‘Rossmann-fold’ structure, members of the SDR superfamily exhibit low sequence similarities, which constituted a bottleneck in terms of identification. Recent classification methods, relying on hidden-Markov models (HMMs, improved identification and enabled the construction of a nomenclature. However, functional annotations of plant SDRs remain scarce. Results Wide-scale analyses were performed on ten plant genomes. The combination of hidden Markov model (HMM based analyses and similarity searches led to the construction of an exhaustive inventory of plant SDR. With 68 to 315 members found in each analysed genome, the inventory confirmed the over-representation of SDRs in plants compared to animals, fungi and prokaryotes. The plant SDRs were first classified into three major types — ‘classical’, ‘extended’ and ‘divergent’ — but a minority (10% of the predicted SDRs could not be classified into these general types (‘unknown’ or ‘atypical’ types. In a second step, we could categorize the vast majority of land plant SDRs into a set of 49 families. Out of these 49 families, 35 appeared early during evolution since they are commonly found through all the Green Lineage. Yet, some SDR families — tropinone reductase-like proteins (SDR65C, ‘ABA2-like’-NAD dehydrogenase (SDR110C, ‘salutaridine/menthone-reductase-like’ proteins (SDR114C, ‘dihydroflavonol 4-reductase’-like proteins (SDR108E and ‘isoflavone-reductase-like’ (SDR460A proteins — have undergone significant functional diversification within vascular plants since they diverged from Bryophytes. Interestingly, these diversified families are either involved in the secondary metabolism routes (terpenoids, alkaloids, phenolics or participate in developmental processes (hormone biosynthesis or

  20. Predicting spiral wave patterns from cell properties in a model of biological self-organization

    Science.gov (United States)

    Geberth, Daniel; Hütt, Marc-Thorsten

    2008-09-01

    In many biological systems, biological variability (i.e., systematic differences between the system components) can be expected to outrank statistical fluctuations in the shaping of self-organized patterns. In principle, the distribution of single-element properties should thus allow predicting features of such patterns. For a mathematical model of a paradigmatic and well-studied pattern formation process, spiral waves of cAMP signaling in colonies of the slime mold Dictyostelium discoideum, we explore this possibility and observe a pronounced anticorrelation between spiral waves and cell properties (namely, the firing rate) and particularly a clustering of spiral wave tips in regions devoid of spontaneously firing (pacemaker) cells. Furthermore, we observe local inhomogeneities in the distribution of spiral chiralities, again induced by the pacemaker distribution. We show that these findings can be explained by a simple geometrical model of spiral wave generation.

  1. Are girls (even) more addicted? Some gender patterns of cell phone usage

    OpenAIRE

    Geser, Hans

    2006-01-01

    Contents: 1. Mobile phones and gender roles; 2. The scope of the present study; 3. Data and Methodology; 4. Empirical results; 4.1 Age patterns of cell phone adoption; 4.2 Intensity of usage; 4.3 Subjective motivations and emotional commitments; 5. Conclusions; References.

  2. (18)F-FDG PET patterns and BAL cell profiles in pulmonary sarcoidosis.

    NARCIS (Netherlands)

    Keijsers, R.G.; Grutters, J.C.; Velzen-Blad, H. van; Bosch, J.M. van den; Oyen, W.J.G.; Verzijlbergen, F.J.

    2010-01-01

    PURPOSE: Bronchoalveolar lavage (BAL) and (18)F-fluorodeoxyglucose ((18)F-FDG) PET can both demonstrate sarcoid activity. To assess whether metabolic activity imaged by (18)F-FDG PET represents signs of disease activity as reflected by BAL, (18)F-FDG PET patterns were compared with BAL cell profiles

  3. Angiogenesis interactome and time course microarray data reveal the distinct activation patterns in endothelial cells.

    Directory of Open Access Journals (Sweden)

    Liang-Hui Chu

    Full Text Available Angiogenesis involves stimulation of endothelial cells (EC by various cytokines and growth factors, but the signaling mechanisms are not completely understood. Combining dynamic gene expression time-course data for stimulated EC with protein-protein interactions associated with angiogenesis (the "angiome" could reveal how different stimuli result in different patterns of network activation and could implicate signaling intermediates as points for control or intervention. We constructed the protein-protein interaction networks of positive and negative regulation of angiogenesis comprising 367 and 245 proteins, respectively. We used five published gene expression datasets derived from in vitro assays using different types of blood endothelial cells stimulated by VEGFA (vascular endothelial growth factor A. We used the Short Time-series Expression Miner (STEM to identify significant temporal gene expression profiles. The statistically significant patterns between 2D fibronectin and 3D type I collagen substrates for telomerase-immortalized EC (TIME show that different substrates could influence the temporal gene activation patterns in the same cell line. We investigated the different activation patterns among 18 transmembrane tyrosine kinase receptors, and experimentally measured the protein level of the tyrosine-kinase receptors VEGFR1, VEGFR2 and VEGFR3 in human umbilical vein EC (HUVEC and human microvascular EC (MEC. The results show that VEGFR1-VEGFR2 levels are more closely coupled than VEGFR1-VEGFR3 or VEGFR2-VEGFR3 in HUVEC and MEC. This computational methodology can be extended to investigate other molecules or biological processes such as cell cycle.

  4. Modification of microridge pattern in teleost (Pimelodus maculatus) epidermal cells induced by NaCl.

    Science.gov (United States)

    Ferri, S

    1983-01-01

    When NaCl is added to the aqueous environment, the fingerprint-like pattern showed by microridges of epidermal superficial cells of the teleost Pimelodus maculatus is modified. This modification probably occurs consequently the rearrangement of cytoplasmic filaments. PMID:6884732

  5. Patterning of polystyrene by scanning electrochemical microscopy. Biological applications to cell adhesion.

    Science.gov (United States)

    Ktari, N; Poncet, P; Sénéchal, H; Malaquin, L; Kanoufi, F; Combellas, C

    2010-11-16

    Polystyrene surfaces may be patterned by Ag(II), NO(3)(•), and OH(•) electrogenerated at the tip of a scanning electrochemical microscope. These electrogenerated reagents lead to local surface oxidation of the polymer. The most efficient surface treatment is obtained with Ag(II). The patterns are evidenced by XPS and IR and also by the surface wettability contrast between the hydrophobic virgin surface and the hydrophilic pattern. Such Ag(II) treatment of a polystyrene Petri dish generates discriminative surfaces able to promote or disfavor the adhesion of proteins and also the adhesion and growth of adherent cells. The process is also successfully applied to a cyclo-olefin copolymer and should be suitable to pattern any hydrogenated polymer. PMID:20945917

  6. Effects of pattern shape on adaptation of dLGN cell

    Institute of Scientific and Technical Information of China (English)

    JIN Jianzhong; XU Pengjing; LI Xiangrui; ZHOU Yifeng

    2003-01-01

    Pattern adaptation is one of the fundamental sensory processes in the visual system. In this study, we compared pattern adaptation induced by two types of sinusoidal drifting grating in dLGN cells of cat. The two types ofgrating have the same parameters (e.g. spatial frequency, temporal frequency and contrast) except their pattern shapes, one of which is normal grating and the other annular grating. The results suggested that the annular grating elicited stronger response and stronger pattern adaptation than the normal grating. This is consistent with the adaptation and aftereffect to the two types of drifting gratings seen in psychology and may reflect the subcortical neural mechanism underlying these psychological phenomena.

  7. Experience of in-cell visual inspection using CCD camera in hot cell of Reprocessing Plant

    International Nuclear Information System (INIS)

    This paper describes the selection, customization and operating experience of the visual inspection system for the hot cell of a Reprocessing Plant. For process equipment such as fuel chopping machine, dissolver, centrifuge, centrifugal extractors etc., viewing of operations and maintenance using manipulators is required. For this, the service of in-cell camera is essential. The ambience of the hot cell of Compact facility for Reprocessing of Advanced fuels in Lead cell (CORAL) for the reprocessing of fast reactor spent fuel has high gamma radiation and acidic vapors. Black and white Charge Coupled Device (CCD) camera has been used in CORAL incorporating in-house modifications to suit the operating ambient conditions, thereby extending the operating life of the camera. (author)

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

    Science.gov (United States)

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

    2016-07-01

    Lead, one of the most abundant and hazardous trace metals affecting living organisms, has been commonly detected in plant cell walls including some tolerant plants, mining ecotypes and hyperaccumulators. We have previously shown that in tip growing Funaria sp. protonemata cell wall is remodeled in response to lead by formation of thickenings rich in low-methylesterified pectins (pectin epitope JIM5 - JIM5-P) able to bind metal ions, which accumulate large amounts of Pb. Hence, it leads to the increase of cell wall capacity for Pb compartmentalization. Here we show that diverse plant species belonging to different phyla (Arabidopsis, hybrid aspen, star duckweed), form similar cell wall thickenings in response to Pb. These thickenings are formed in tip growing cells such as the root hairs, and in diffuse growing cells such as meristematic and root cap columella cells of root apices in hybrid aspen and Arabidopsis and in mesophyll cells in star duckweed fronds. Notably, all analyzed cell wall thickenings were abundant in JIM5-P and accumulated high amounts of Pb. In addition, the co-localization of JIM5-P and Pb commonly occurred in these cells. Hence, cell wall thickenings formed the extra compartment for Pb accumulation. In this way plant cells increased cell wall capacity for compartmentalization of this toxic metal, protecting protoplast from its toxicity. As cell wall thickenings occurred in diverse plant species and cell types differing in the type of growth we may conclude that pectinous cell wall thickenings formation is a widespread defense strategy of plants to cope with Pb. Moreover, detection of natural defense strategy, increasing plant cell walls capacity for metal accumulation, reveals a promising direction for enhancing plant efficiency in phytoremediation. PMID:27107260

  9. Aggregation patterns of fetal rat brain cells following exposure to X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, R.; Suzuki, K.; Lee, I.P.

    1980-01-01

    In our search for a simplified in vitro test system to assess the teratogenic effects of physical factors, we studied the effects of total maternal body X-irradiation on aggregation patterns of enzymatically isolated fetal rat brain cells and on ultrastructural aggregate changes. The fetal brain cells were derived from day 14 gestation fetuses of pregnant Sprague-Dawley (CD strain) rats exposed to X-irradiation (25 - 200 R) one hour prior to sacrifice. Notable changes in the cell aggregates following X-irradiation included a reduction in cell aggregate size and an increase in number. The frequency of cell aggregates was higher in the treated than in the control group, and the mean diameter of cell aggregates was inversely related to increasing X-irradiation doses. Transmission electron microscopy revealed in isolated cells features of degenerative process which were similar to those found in intact fetal brain lesions caused by maternal X-irradiation. Furthermore, scanning electron microscopy revealed that inhibition of cell aggregation following X-irradiation could probably be attributed to inhibition of membrane filopodia development and a consequent failure of cell aggregates to fuse into a greater cell aggregate mass. These results suggest that the membrane factors which influence cell aggregation may be a useful parameter to assess early effects of X-irradiation-induced brain deformity. Presently, the cell aggregation culture system is being further evaluated as a short term test system for environmental teratogens.

  10. Displacement of organelles in plant gravireceptor cells by vibrational forces and ultrasound.

    Science.gov (United States)

    Kuznetsov, O.; Nechitailo, G.; Kuznetsov, A.

    Plant gravity perception can be studied by displacing statoliths inside receptor cells by forces other than gravity. Due to mechanical heterogeneity of statocytes various ponderomotive forces can be used for this purpose. In a plant subjected to non- symmetric vibrations statoliths experience inertial force proportional to the difference between their density and that of cytoplasm and to the instantaneous acceleration of the cell. This force causes cyclic motion of statoliths relative to cytoplasm and, depending on the profile of oscillations, can result in a net displacement of them (due to complex rheology of the cell interior), similar to sedimentation. This can be described as "vibrational" ponderomotive force acting on the statoliths. Vertically growing Arabidopsis seedlings, subjected to horizontal, sawtooth shaped oscillations (250 Hz, 1.5 mm amplitude), showed 17+/-2o root curvature toward and shoot curvature of 11+/-3o against the stronger acceleration. When the polarity of the oscillations was reversed, the direction of curvature of shoots and roots was also reversed. Control experiments with starchless mutants (TC7) produced no net curvature, which indicates that dense starch-filled amyloplasts are needed for the effect. These control experiments also eliminate touch-induced reactions or other side-effects as the cause of the curvature. Linum roots curved 25+/-7o . Ceratodon protonemata subjected to the same oscillations have shown displacement of plastids and curvature consistent with the pattern observed during graviresponse: positively gravitropic wwr mutant curved in the direction of the plastid displacement, WT curved in the opposite direction. Acoustic ponderomotive forces, originating from transfer of a sonic beam momentum to the medium due to sound scattering and attenuation in a mechanically heterogeneous system, also can displace statoliths. Vertical flax seedlings curved away from the ultrasonic source (800 kHz, 0.1 W/cm2 ) presumably as a

  11. Cell state switching factors and dynamical patterning modules: complementary mediators of plasticity in development and evolution

    Indian Academy of Sciences (India)

    Stuart A Newman; Ramray Bhat; Nadejda V Mezentseva

    2009-10-01

    Ancient metazoan organisms arose from unicellular eukaryotes that had billions of years of genetic evolution behind them. The transcription factor networks present in single-celled ancestors at the origin of the Metazoa (multicellular animals) were already capable of mediating the switching of the unicellular phenotype among alternative states of gene activity in response to environmental conditions. Cell differentiation, therefore, had its roots in phenotypic plasticity, with the ancient regulatory proteins acquiring new targets over time and evolving into the ``developmental transcription factors” (DTFs) of the ``developmental-genetic toolkit.” In contrast, the emergence of pattern formation and morphogenesis in the Metazoa had a different trajectory. Aggregation of unicellular metazoan ancestors changed the organisms’ spatial scale, leading to the first ``dynamical patterning module” (DPM): cell-cell adhesion. Following this, other DPMs (defined as physical forces and processes pertinent to the scale of the aggregates mobilized by a set of toolkit gene products distinct from the DTFs), transformed simple cell aggregates into hollow, multilayered, segmented, differentiated and additional complex structures, with minimal evolution of constituent genes. Like cell differentiation, therefore, metazoan morphologies also originated from plastic responses of cells and tissues. Here we describe examples of DTFs and most of the important DPMs, discussing their complementary roles in the evolution of developmental mechanisms. We also provide recently characterized examples of DTFs in cell type switching and DPMs in morphogenesis of avian limb bud mesenchyme, an embryo-derived tissue that retains a high degree of developmental plasticity.

  12. Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells

    KAUST Repository

    Liu, Jia

    2014-12-01

    Power production in microbial reverse-electrodialysis cells (MRCs) can be limited by the internal resistance of the reverse electrodialysis stack. Typical MRC stacks use non-conductive spacers that block ion transport by the so-called spacer shadow effect. These spacers can be relatively thick compared to the membrane, and thus they increase internal stack resistance due to high solution (ohmic) resistance associated with a thick spacer. New types of patterned anion and cation exchange membranes were developed by casting membranes to create hemispherical protrusions on the membranes, enabling fluid flow between the membranes without the need for a non-conductive spacer. The use of the patterned membrane decreased the MRC stack resistance by ∼22 Ω, resulting in a 38% increase in power density from 2.50 ± 0.04 W m-2 (non-patterned membrane with a non-conductive spacer) to 3.44 ± 0.02 W m-2 (patterned membrane). The COD removal rate, coulombic efficiency, and energy efficiency of the MRC also increased using the patterned membranes compared to the non-patterned membranes. These results demonstrate that these patterned ion exchange membranes can be used to improve performance of an MRC. © 2014 Elsevier B.V. All rights reserved.

  13. The patterning of retinal horizontal cells: normalizing the regularity index enhances the detection of genomic linkage

    Directory of Open Access Journals (Sweden)

    Patrick W. Keeley

    2014-10-01

    Full Text Available Retinal neurons are often arranged as non-random distributions called mosaics, as their somata minimize proximity to neighboring cells of the same type. The horizontal cells serve as an example of such a mosaic, but little is known about the developmental mechanisms that underlie their patterning. To identify genes involved in this process, we have used three different spatial statistics to assess the patterning of the horizontal cell mosaic across a panel of genetically distinct recombinant inbred strains. To avoid the confounding effect cell density, which varies two-fold across these different strains, we computed the real/random regularity ratio, expressing the regularity of a mosaic relative to a randomly distributed simulation of similarly sized cells. To test whether this latter statistic better reflects the variation in biological processes that contribute to horizontal cell spacing, we subsequently compared the genetic linkage for each of these two traits, the regularity index and the real/random regularity ratio, each computed from the distribution of nearest neighbor (NN distances and from the Voronoi domain (VD areas. Finally, we compared each of these analyses with another index of patterning, the packing factor. Variation in the regularity indexes, as well as their real/random regularity ratios, and the packing factor, mapped quantitative trait loci (QTL to the distal ends of Chromosomes 1 and 14. For the NN and VD analyses, we found that the degree of linkage was greater when using the real/random regularity ratio rather than the respective regularity index. Using informatic resources, we narrow the list of prospective genes positioned at these two intervals to a small collection of six genes that warrant further investigation to determine their potential role in shaping the patterning of the horizontal cell mosaic.

  14. Patterns and drivers of fuelwood collection and tree planting in a Middle Hill watershed of Nepal

    International Nuclear Information System (INIS)

    The majority of residents in the rural Middle Hills of Nepal use fuelwood from public and private sources as their primary energy source. This study investigated fuelwood availability in accessed forests, amount of fuelwood collected, preferred tree species for fuelwood, contribution of public and private sources to total fuelwood consumption, and investment in tree planting on agricultural land. Fuelwood availability declined in the decades prior to 1990, but stabilized by 1990. Fuelwood from fifty-three species was collected from forests. Median annual per capita collection was 683 kg and predicted only by family size. Occupational castes ('low castes') did not show different harvesting rates than non-occupational castes and non-caste ethnic groups. Wealth was not associated with total fuelwood collection, probably because there was no fuelwood market. Most households collected fuelwood from a private source, namely trees planted on sloping, rain-fed agricultural land (bari), but this accounted for only a small portion of most households' requirement. Bari landholding area and livestock holdings-typical measures of wealth-drove the decision to plant trees on bari land, and the number of trees that were planted. Bari-poor and landless households were consequently the most vulnerable to forest degradation, so the promotion of private fuelwood planting by large bari landholders could reduce pressure on forests and promote greater fuelwood availability for landless households. Support of community forestry emphasizing access for bari-poor and landless families could further decrease fuelwood vulnerability of poorer households. (author)

  15. Micro checkerboard patterned polymeric surface with discrete rigidity for studying cell migration

    Science.gov (United States)

    Hong, Juhee; Lee, Sujin; Park, Sukho; Lee, Junghoon

    2015-04-01

    The control of cell migration has an important role in processes ranging from developmental morphogenesis to the pathogenesis. In this study, we describe a novel approach to develop a micro-checkerboard patterned polymeric flat surface with discrete surface stiffness. This platform as a culture substrate allows us to explore the mechanism of durotaxis, referred to as the directed cell movement via the gradient of surface stiffness. The flat surface with different rigidity was achieved in two stages of fabrication. First, polydimethylsiloxane (PDMS) was pressed and cured on a glass substrate with trenches of varying depths in a checkerboard arrangement, and then, a thin PDMS layer was spin coated on the previous pattern to make the flat surface. The stiff region is defined by a thin layer (2.5 µm) of PDMS and the soft region is defined by a thick one (7.5 µm). To investigate the migratory cell behavior, the NIH 3T3 cell was cultured. The result demonstrates that a single cell showed clearly a migratory cell behavior toward the stiffer regions driven by the difference of effective surface stiffness. At high cell density, the effect of cell migration on effective surface stiffness decreased with increasing cell-cell interactions. However, cell migration was still dominated by difference of effective surface stiffness while fluctuating at the boundary between the stiff and soft regions. This approach enables us to control the mechanical and topological properties of surface. The developed platform will also offer a useful tool to study cell-substrate interaction mediated by surface stiffness (e.g. mechanotransduction).

  16. Actin based processes that could determine the cytoplasmic architecture of plant cells

    OpenAIRE

    Honing; Emons, A.M.C.; Ketelaar, M.J.

    2007-01-01

    Actin polymerisation can generate forces that are necessary for cell movement, such as the propulsion of a class of bacteria, including Listeria, and the protrusion of migrating animal cells. Force generation by the actin cytoskeleton in plant cells has not been studied. One process in plant cells that is likely to depend on actin-based force generation is the organisation of the cytoplasm. We compare the function of actin binding proteins of three well-studied mammalian models that depend on...

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

    OpenAIRE

    Bellincampi, Daniela; Cervone, Felice; Lionetti, Vincenzo

    2014-01-01

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

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

    OpenAIRE

    Cosgrove, Daniel J.

    2016-01-01

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

  19. Analysis of small RNA production patterns among the two potato spindle tuber viroid variants in tomato plants.

    Science.gov (United States)

    Adkar-Purushothama, Charith Raj; Perreault, Jean-Pierre; Sano, Teruo

    2015-12-01

    In order to analyze the production of small RNA (sRNA) by viroids upon infecting the plants, the tomato plants (Solanum lycopersicum cultivar Rutgers) were inoculated with the variants of Potato spindle tuber viroid (PSTVd). After 21-days of postinoculation, total RNA was extracted and subjected for deep-sequencing using Illumina HiSeq platform. The primers were trimmed and only 21- to 24-nt long sRNAs were filtered after quality check of the raw data. The filtered sRNA population was then mapped against both the genomic (+) and antigenomic (-) strands of the respective PSTVd variants using standard pattern-matching algorithm. The profiling of viroid derived sRNA (vd-sRNA) revealed that the viroids are susceptible to host RNA silencing mechanism. High-throughput sequence data linked to this project have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE69225. PMID:26697336

  20. Analysis of small RNA production patterns among the two potato spindle tuber viroid variants in tomato plants

    Directory of Open Access Journals (Sweden)

    Charith Raj Adkar-Purushothama

    2015-12-01

    Full Text Available In order to analyze the production of small RNA (sRNA by viroids upon infecting the plants, the tomato plants (Solanum lycopersicum cultivar Rutgers were inoculated with the variants of Potato spindle tuber viroid (PSTVd. After 21-days of postinoculation, total RNA was extracted and subjected for deep-sequencing using Illumina HiSeq platform. The primers were trimmed and only 21- to 24-nt long sRNAs were filtered after quality check of the raw data. The filtered sRNA population was then mapped against both the genomic (+ and antigenomic (− strands of the respective PSTVd variants using standard pattern-matching algorithm. The profiling of viroid derived sRNA (vd-sRNA revealed that the viroids are susceptible to host RNA silencing mechanism. High-throughput sequence data linked to this project have been deposited in the Gene Expression Omnibus (GEO database under accession number GSE69225.