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Sample records for cell patterning plant

  1. Auxin Acts through MONOPTEROS to Regulate Plant Cell Polarity and Pattern Phyllotaxis.

    Science.gov (United States)

    Bhatia, Neha; Bozorg, Behruz; Larsson, André; Ohno, Carolyn; Jönsson, Henrik; Heisler, Marcus G

    2016-12-05

    The periodic formation of plant organs such as leaves and flowers gives rise to intricate patterns that have fascinated biologists and mathematicians alike for hundreds of years [1]. The plant hormone auxin plays a central role in establishing these patterns by promoting organ formation at sites where it accumulates due to its polar, cell-to-cell transport [2-6]. Although experimental evidence as well as modeling suggest that feedback from auxin to its transport direction may help specify phyllotactic patterns [7-12], the nature of this feedback remains unclear [13]. Here we reveal that polarization of the auxin efflux carrier PIN-FORMED 1 (PIN1) is regulated by the auxin response transcription factor MONOPTEROS (MP) [14]. We find that in the shoot, cell polarity patterns follow MP expression, which in turn follows auxin distribution patterns. By perturbing MP activity both globally and locally, we show that localized MP activity is necessary for the generation of polarity convergence patterns and that localized MP expression is sufficient to instruct PIN1 polarity directions non-cell autonomously, toward MP-expressing cells. By expressing MP in the epidermis of mp mutants, we further show that although MP activity in a single-cell layer is sufficient to promote polarity convergence patterns, MP in sub-epidermal tissues helps anchor these polarity patterns to the underlying cells. Overall, our findings reveal a patterning module in plants that determines organ position by orienting transport of the hormone auxin toward cells with high levels of MP-mediated auxin signaling. We propose that this feedback process acts broadly to generate periodic plant architectures.

  2. A Theoretical Model of Jigsaw-Puzzle Pattern Formation by Plant Leaf Epidermal Cells.

    Science.gov (United States)

    Higaki, Takumi; Kutsuna, Natsumaro; Akita, Kae; Takigawa-Imamura, Hisako; Yoshimura, Kenji; Miura, Takashi

    2016-04-01

    Plant leaf epidermal cells exhibit a jigsaw puzzle-like pattern that is generated by interdigitation of the cell wall during leaf development. The contribution of two ROP GTPases, ROP2 and ROP6, to the cytoskeletal dynamics that regulate epidermal cell wall interdigitation has already been examined; however, how interactions between these molecules result in pattern formation remains to be elucidated. Here, we propose a simple interface equation model that incorporates both the cell wall remodeling activity of ROP GTPases and the diffusible signaling molecules by which they are regulated. This model successfully reproduces pattern formation observed in vivo, and explains the counterintuitive experimental results of decreased cellulose production and increased thickness. Our model also reproduces the dynamics of three-way cell wall junctions. Therefore, this model provides a possible mechanism for cell wall interdigitation formation in vivo.

  3. Central Cell-Derived Peptides Regulate Early Embryo Patterning in Flowering Plants

    NARCIS (Netherlands)

    Costa, L.M.; Marshall, E.; Tesfaye, M.; Silverstein, K.A.T.; Mori, M.; Umetsu, Y.; Otterbach, S.L.; Papareddy, R.; Dickinson, H.G.; Boutilier, K.A.; VandenBosch, K.A.; Ohki, S.; Gutierrez-Marcos, J.F.

    2014-01-01

    Plant embryogenesis initiates with the establishment of an apical-basal axis; however, the molecular mechanisms accompanying this early event remain unclear. Here, we show that a small cysteine-rich peptide family is required for formation of the zygotic basal cell lineage and proembryo patterning i

  4. Phyllotactic Patterns on Plants

    Science.gov (United States)

    Shipman, Patrick D.; Newell, Alan C.

    2004-04-01

    We demonstrate how phyllotaxis (the arrangement of leaves on plants) and the deformation configurations seen on plant surfaces may be understood as the energy-minimizing buckling pattern of a compressed shell (the plant's tunica) on an elastic foundation. The key new idea is that the strain energy is minimized by configurations consisting of special triads of almost periodic deformations. We reproduce a wide spectrum of plant patterns, all with the divergence angles observed in nature, and show how the occurrences of Fibonacci-like sequences and the golden angle are natural consequences.

  5. Evaluation of diel patterns of relative changes in cell turgor of tomato plants using leaf patch clamp pressure probes

    NARCIS (Netherlands)

    Lee, K.M.; Driever, S.M.; Heuvelink, E.; Rüger, S.; Zimmermann, U.; Gelder, de A.; Marcelis, L.F.M.

    2012-01-01

    Relative changes in cell turgor of leaves of well-watered tomato plants were evaluated using the leaf patch clamp pressure probe (LPCP) under dynamic greenhouse climate conditions. Leaf patch clamp pressure changes, a measure for relative changes in cell turgor, were monitored at three different hei

  6. Patterns of plant subcellular responses to successful oomycete infections reveal differences in host cell reprogramming and endocytic trafficking

    Science.gov (United States)

    Lu, Yi-Ju; Schornack, Sebastian; Spallek, Thomas; Geldner, Niko; Chory, Joanne; Schellmann, Swen; Schumacher, Karin; Kamoun, Sophien; Robatzek, Silke

    2016-01-01

    Summary Adapted filamentous pathogens such as the oomycetes Hyaloperonospora arabidopsidis (Hpa) and Phytophthora infestans (Pi) project specialized hyphae, the haustoria, inside living host cells for the suppression of host defence and acquisition of nutrients. Accommodation of haustoria requires reorganization of the host cell and the biogenesis of a novel host cell membrane, the extrahaustorial membrane (EHM), which envelops the haustorium separating the host cell from the pathogen. Here, we applied live-cell imaging of fluorescent-tagged proteins labelling a variety of membrane compartments and investigated the subcellular changes associated with accommodating oomycete haustoria in Arabidopsis and N. benthamiana. Plasma membrane-resident proteins differentially localized to the EHM. Likewise, secretory vesicles and endosomal compartments surrounded Hpa and Pi haustoria revealing differences between these two oomycetes, and suggesting a role for vesicle trafficking pathways for the pathogen-controlled biogenesis of the EHM. The latter is supported by enhanced susceptibility of mutants in endosome-mediated trafficking regulators. These observations point at host subcellular defences and specialization of the EHM in a pathogen-specific manner. Defence-associated haustorial encasements, a double-layered membrane that grows around mature haustoria, were frequently observed in Hpa interactions. Intriguingly, all tested plant proteins accumulated at Hpa haustorial encasements suggesting the general recruitment of default vesicle trafficking pathways to defend pathogen access. Altogether, our results show common requirements of subcellular changes associated with oomycete biotrophy, and highlight differences between two oomycete pathogens in reprogramming host cell vesicle trafficking for haustoria accommodation. This provides a framework for further dissection of the pathogen-triggered reprogramming of host subcellular changes. PMID:22233428

  7. Plant stem cell niches.

    Science.gov (United States)

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

    2012-01-01

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

  8. 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.

  9. Cell-penetrating peptides: From mammalian to plant cells

    OpenAIRE

    Eudes, François; Chugh, Archana

    2008-01-01

    Internalization of cell-penetrating peptides, well described in mammalian cell system, has recently been reported in a range of plant cells by three independent groups. Despite fundamental differences between animal cell and plant cell composition, the CPP uptake pattern between the mammalian system and the plant system is very similar. Tat, Tat-2 pVEC and transportan internalisation is concentration dependent and non saturable, enhanced at low temperature (4°C), and receptor independent. The...

  10. 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.

  11. 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...

  12. Modulation of the degree and pattern of methyl-esterification of pectic homogalacturonan in plant cell walls

    NARCIS (Netherlands)

    Willats, W.G.T.; Orfila, C.; Limberg, G.; Buchholt, H.C.; Alebeek, van G.J.W.M.; Voragen, A.G.J.; Marcus, S.E.

    2001-01-01

    From the Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom, § Danisco Biotechnology, Langebrogade 1, DK 1001 Copenhagen K, Denmark, Danisco Cultor, Edwin Rahrs Vej 38, DK-8220 Brabrand, Denmark, the ** Department of Agrotechnology and Food Sciences, Laboratory of Food Che

  13. Dense pattern multiple pass cells

    Science.gov (United States)

    Silver, Joel A.; Bomse, David S.

    2010-09-21

    An optical cell and a method of operating an optical cell comprising employing a first mirror comprising a first hole therein at approximately a center of the first mirror and through which laser light enters the cell, employing a second mirror comprising a second hole therein at approximately a center of the second mirror and through which laser light exits the cell, and forming a Lissajous pattern of spots on the mirrors by repeated reflection of laser light entering the cell.

  14. 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.

  15. MAMP (Microbe-Associated Molecular Pattern triggered immunity in Plants

    Directory of Open Access Journals (Sweden)

    Mari-Anne eNewman

    2013-05-01

    Full Text Available Plants are sessile organisms that are under constant attack from microbes. They rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. Preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. The plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting most potentially harmful microbes. The elicitors are essential structures for pathogen survival and are conserved among pathogens. The conserved microbe-specific molecules, referred to as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs, are recognized by the plant innate immune systems pattern recognition receptors (PRRs. General elicitors like flagellin (Flg, elongation factor Tu (EF-Tu, peptidoglycan (PGN, lipopolysaccharides (LPS, Ax21 (Activator of XA21-mediated immunity in rice, fungal chitin and β-glucans from oomycetes are recognized by plant surface localized PRRs. Several of the MAMPs and their corresponding PRRs have, in recent years, been identified. This review focuses on the current knowledge regarding important MAMPs from bacteria, fungi and oomycetes, their structure, the plant PRRs that recognizes them, and how they induce MAMP-triggered immunity (MTI in plants.

  16. Plant biodiversity patterns on Helan Mountain, China

    Science.gov (United States)

    Jiang, Yuan; Kang, Muyi; Zhu, Yuan; Xu, Guangcai

    2007-09-01

    A case study was conducted to mountainous ecosystems in the east side of Helan Mountain, located in the transitional zone between steppe and desert regions of China, aiming to reveal the influences of four environmental factors on features of plant biodiversity—the spatial pattern of vegetation types, and the variation of α- and β-diversities in vegetation and flora. Field surveys on vegetation and flora and on environmental factors were conducted, and those field data were analyzed through CCA (Canonical Correspondence Analysis), and through Shannon-Weiner index for α-diversity and Sørensen index for β-diversity. The preliminary results are: (1) Ranked in terms of their impacts on spatial patterns of plant biodiversity, the four selected environmental factors would be: elevation > location > slope > exposure. (2) The variation of Shannon-Weiner index along the altitudinal gradient is similar to that of species amount within altitudinal belts spanning 200 m each, which suggests a unimodal relationship between the species richness and the environmental condition with regards to altitudinal factors. Both the Shannon-Weiner index and the species richness within each altitudinal belt reach their maximum at elevation range from about 1700 to 2000 m a.s.l. (3) The altitudinal extent with the highest Shannon-Weiner index is identical to the range, where both the deciduous broad-leaved forest, and the temperate evergreen coniferous and deciduous broad-leaved mixed forest distribute. The altitudinal range from 1700 to 2200 m a.s.l. is the sector with both high level of species richness and diversified vegetation types. (4) The variation of β-diversity along the altitude is consistent with the vegetation vertical zones. According to the Sørensen index between each pair of altitudinal belts, the transition of vegetation spectrum from one zone to another, as from the base horizontal zone, the desert steppe, to the first vertical zone, the mountain open forest and

  17. 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

  18. Cell patterning with mucin biopolymers

    Science.gov (United States)

    Crouzier, T.; Jang, H.; Ahn, J.; Stocker, R.; Ribbeck, K.

    2014-01-01

    The precise spatial control of cell adhesion to surfaces is an endeavor that has enabled discoveries in cell biology and new possibilities in tissue engineering. The generation of cell-repellent surfaces currently requires advanced chemistry techniques and could be simplified. Here we show that mucins, glycoproteins of high structural and chemical complexity, spontaneously adsorb on hydrophobic substrates to form coatings that prevent the surface adhesion of mammalian epithelial cells, fibroblasts, and myoblasts. These mucin coatings can be patterned with micrometer precision using a microfluidic device, and are stable enough to support myoblast differentiation over seven days. Moreover, our data indicate that the cell-repellent effect is dependent on mucin-associated glycans because their removal results in a loss of effective cell-repulsion. Last, we show that a critical surface density of mucins, which is required to achieve cell-repulsion, is efficiently obtained on hydrophobic surfaces, but not on hydrophilic glass surfaces. However, this limitation can be overcome by coating glass with hydrophobic fluorosilane. We conclude that mucin biopolymers are attractive candidates to control cell adhesion on surfaces. PMID:23980712

  19. 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.

  20. Maize Yields Performance in Strip Planting Patterns with Two Plant Densities

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2015-07-01

    Full Text Available The Huang-Huai-Hai Plain is the most important maize production region in China. To further investigate the improvement of maize yield by changing the planting pattern combined with two plant densities in this region, field experiments involving four planting patterns (three-row strip, four-row strip, five-row strip and a conventional uniform row spacing pattern (the control under two plant densities (67,500 and 82,500 plants/ha were conducted in 2011 and 2012. Only the plant density, not the planting pattern, significantly influenced the leaf area index at R1 stage and the total leaf area duration. The radiation use efficiency and the above-ground biomass at R5 were both higher under the three strip planting patterns than under the control, but the differences were not statistically significant. The effects of the planting patterns on the grain yield were significant in both years and the yields were 16.7, 6.1 and 10.7%, respectively higher in 2011 and 17.2, 12.1 and 10.6%, respectively higher in 2012 under the three-, four- and five-row strip treatments, respectively, compared with the control. However, grain yield was affected by neither plant density nor the interaction between planting pattern and plant density. Therefore, optimal strip planting pattern could not be better estimated by considering plant density.

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

    Science.gov (United States)

    Macho, Alberto P; Schwessinger, Benjamin; Ntoukakis, Vardis; Brutus, Alexandre; Segonzac, Cécile; Roy, Sonali; Kadota, Yasuhiro; Oh, Man-Ho; Sklenar, Jan; Derbyshire, Paul; Lozano-Durán, Rosa; Malinovsky, Frederikke Gro; Monaghan, Jacqueline; Menke, Frank L; Huber, Steven C; He, Sheng Yang; Zipfel, Cyril

    2014-03-28

    Innate immunity relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs) located on the host cell's surface. Many plant PRRs are kinases. Here, we report that the Arabidopsis receptor kinase EF-TU RECEPTOR (EFR), which perceives the elf18 peptide derived from bacterial elongation factor Tu, is activated upon ligand binding by phosphorylation on its tyrosine residues. Phosphorylation of a single tyrosine residue, Y836, is required for activation of EFR and downstream immunity to the phytopathogenic bacterium Pseudomonas syringae. A tyrosine phosphatase, HopAO1, secreted by P. syringae, reduces EFR phosphorylation and prevents subsequent immune responses. Thus, host and pathogen compete to take control of PRR tyrosine phosphorylation used to initiate antibacterial immunity.

  2. 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.

  3. Optimizing Grid Patterns on Photovoltaic Cells

    Science.gov (United States)

    Burger, D. R.

    1984-01-01

    CELCAL computer program helps in optimizing grid patterns for different photovoltaic cell geometries and metalization processes. Five different powerloss phenomena associated with front-surface metal grid pattern on photovoltaic cells.

  4. Involvement of bacterial TonB-dependent signaling in the generation of an oligogalacturonide damage-associated molecular pattern from plant cell walls exposed to Xanthomonas campestris pv. campestris pectate lyases

    Directory of Open Access Journals (Sweden)

    Vorhölter Frank-Jörg

    2012-10-01

    Full Text Available Abstract Background Efficient perception of attacking pathogens is essential for plants. Plant defense is evoked by molecules termed elicitors. Endogenous elicitors or damage-associated molecular patterns (DAMPs originate from plant materials upon injury or pathogen activity. While there are comparably well-characterized examples for DAMPs, often oligogalacturonides (OGAs, generated by the activity of fungal pathogens, endogenous elicitors evoked by bacterial pathogens have been rarely described. In particular, the signal perception and transduction processes involved in DAMP generation are poorly characterized. Results A mutant strain of the phytopathogenic bacterium Xanthomonas campestris pv. campestris deficient in exbD2, which encodes a component of its unusual elaborate TonB system, had impaired pectate lyase activity and caused no visible symptoms for defense on the non-host plant pepper (Capsicum annuum. A co-incubation of X. campestris pv. campestris with isolated cell wall material from C. annuum led to the release of compounds which induced an oxidative burst in cell suspension cultures of the non-host plant. Lipopolysaccharides and proteins were ruled out as elicitors by polymyxin B and heat treatment, respectively. After hydrolysis with trifluoroacetic acid and subsequent HPAE chromatography, the elicitor preparation contained galacturonic acid, the monosaccharide constituent of pectate. OGAs were isolated from this crude elicitor preparation by HPAEC and tested for their biological activity. While small OGAs were unable to induce an oxidative burst, the elicitor activity in cell suspension cultures of the non-host plants tobacco and pepper increased with the degree of polymerization (DP. Maximal elicitor activity was observed for DPs exceeding 8. In contrast to the X. campestris pv. campestris wild type B100, the exbD2 mutant was unable to generate elicitor activity from plant cell wall material or from pectin. Conclusions To our

  5. 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

  6. 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

  7. Plant-herbivore interaction: dissection of the cellular pattern of Tetranychus urticae feeding on the host plant

    Directory of Open Access Journals (Sweden)

    Nicolas Bensoussan

    2016-07-01

    Full Text Available The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae, is one of the most polyphagous herbivores feeding on cell contents of over 1,100 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.

  8. 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.

  9. Microanalysis of Plant Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  10. Nuclear lamina in plant cells

    Institute of Scientific and Technical Information of China (English)

    汪健; 杨澄; 翟中和

    1996-01-01

    By using selective extraction and diethylene glycol distearate (DGD) embedment and embedment-free electron microscopy, the nuclear lamina was demonstrated in carrot and Ginkgo male generative cells. Western blotting revealed that the nuclear lamina was composed of A-type and B-type lamins which contained at least 66-ku and 84-ku or 66-ku and 86-ku polypeptides, respectively. These lamin proteins were localized at the nudear periphery as shown by immunogold-labelling. In situ hybridization for light microscope and electron microscope showed that plant cells have the homologous sequences of animal lamin cDNA. The sorting site of lamin mRNA is mainly distributed in the cytoplasm near the nudear envelope. The data have verified that there indeed exists nudear lamina in plant cells.

  11. 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.

  12. Assessing Risk in Chemical Plant with Pattern Matching

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper discusses potential application of fuzzy set theory, more specifically, pattern matching, in assessing risk in chemical plants. Risk factors have been evaluated using linguistic representations of the quantity of the hazardous substance involved, its frequency of interaction with the environment, severity of its impact and the uncertainty involved in its detection in advance. For each linguistic value there is a corresponding membership function ranging over a universe of discourse. The risk scenario created by a hazard/hazardous situation having highest degree of featural value is taken as the known pattern. Each sample pattern of hazard/hazardous situation with their known featural values is then matched with the known pattern. The concept of multifeature pattern matching based on fuzzy logic is used to derive the rank ordering of process hazards. In multifeature pattern recognition/matching, a sample pattern is compared to a number of known data patterns or a known pattern is compared to a number of sample data patterns. The process assesses which known pattern resembles most closely data sample using Wang's approaching degree method. A methodology has been developed and the same has been exemplified by presenting a case example with a limited number of hazards.

  13. Magnetic-directed patterning of cell spheroids.

    Science.gov (United States)

    Whatley, Benjamin R; Li, Xiaowei; Zhang, Ning; Wen, Xuejun

    2014-05-01

    We have described an approach to fabricate three-dimensional (3D) cell-based structures using functionalized super paramagnetic iron oxide nanoparticles (SPIONs) as patterning agents to guide the assembly of endothelial cell spheroids into 3D patterns using the magnetic forces generated by a prefabricated magnetic template. SPIONs were first uptaken by endothelial cells before they were assembled into uniform-sized spheroids through a home-made robotic spheroid maker. To guide the magnetic spheroids, a unique magnetic template was fabricated using computer-aided design and cut from a magnetic sheet. The spheroids were then guided to the prefabricated magnetic template through the attractive magnetic forces between the SPIONs inside the endothelial cells and the magnetic template. Fusion of endothelial cell spheroids over time while adhered to the magnetic template allowed for the formation of 3D cell-based structures. Subsequent removal of the prefabricated magnetic template left 3-D endothelial cell sheets, which may be stacked to fabricate complicated 3D multicellular tissue structures. To enhance the cytocompatibility, SPIONs were silica-coated before use. At low concentrations, the SPIONs did not adversely affect cell viability, proliferation, and phenotype stability. Light and confocal microscopy showed that endothelial cell spheroids could be reproducibly created with high uniformity. The endothelial cells were able to remain viable and maintain the 3D structure in vitro. We have proved the concept to use SPIONs as a patterning agent to direct the attachment and self assembly of SPION-loaded endothelial cell spheroids on a prefabricated magnetic template for the formation of 3D cell based structures. A magnetic-directed technique allows quick patterning of cell spheroids in accordance with desirable magnetic patterns, therefore, holding promise for scalable fabrication of complicated 3D multicellular tissue structures. By varying the cell types and the

  14. 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

  15. Customized color patterning of photovoltaic cells

    Science.gov (United States)

    Cruz-Campa, Jose Luis; Nielson, Gregory N.; Okandan, Murat; Lentine, Anthony L.; Resnick, Paul J.; Gupta, Vipin P.

    2016-11-15

    Photovoltaic cells and photovoltaic modules, as well as methods of making and using such photovoltaic cells and photovoltaic modules, are disclosed. More particularly, embodiments of the photovoltaic cells selectively reflect visible light to provide the photovoltaic cells with a colorized appearance. Photovoltaic modules combining colorized photovoltaic cells may be used to harvest solar energy while providing a customized appearance, e.g., an image or pattern.

  16. Regio- and stereoselectivities in plant cell biotransformation

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, H. [Okayama Univ. of Science (Japan)

    1995-12-01

    The ability of plant cultured cells to convert foreign substrates into more useful substances is of considerable interest. Therefore I have studied biotransformation of foreign substrate by plant cell suspension cultures. In this presentation, I report regio- and stereoselectivities in biotransformation of steroids and indole alkaloids and taxol by plant (tobacco, periwinkle, moss, orchid) cell suspension cultures.

  17. Deterministic patterns in cell motility

    Science.gov (United States)

    Lavi, Ido; Piel, Matthieu; Lennon-Duménil, Ana-Maria; Voituriez, Raphaël; Gov, Nir S.

    2016-12-01

    Cell migration paths are generally described as random walks, associated with both intrinsic and extrinsic noise. However, complex cell locomotion is not merely related to such fluctuations, but is often determined by the underlying machinery. Cell motility is driven mechanically by actin and myosin, two molecular components that generate contractile forces. Other cell functions make use of the same components and, therefore, will compete with the migratory apparatus. Here, we propose a physical model of such a competitive system, namely dendritic cells whose antigen capture function and migratory ability are coupled by myosin II. The model predicts that this coupling gives rise to a dynamic instability, whereby cells switch from persistent migration to unidirectional self-oscillation, through a Hopf bifurcation. Cells can then switch to periodic polarity reversals through a homoclinic bifurcation. These predicted dynamic regimes are characterized by robust features that we identify through in vitro trajectories of dendritic cells over long timescales and distances. We expect that competition for limited resources in other migrating cell types can lead to similar deterministic migration modes.

  18. 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…

  19. 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

  20. 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

  1. Caenorhabditis elegans vulval cell fate patterning

    Science.gov (United States)

    Félix, Marie-Anne

    2012-08-01

    The spatial patterning of three cell fates in a row of competent cells is exemplified by vulva development in the nematode Caenorhabditis elegans. The intercellular signaling network that underlies fate specification is well understood, yet quantitative aspects remain to be elucidated. Quantitative models of the network allow us to test the effect of parameter variation on the cell fate pattern output. Among the parameter sets that allow us to reach the wild-type pattern, two general developmental patterning mechanisms of the three fates can be found: sequential inductions and morphogen-based induction, the former being more robust to parameter variation. Experimentally, the vulval cell fate pattern is robust to stochastic and environmental challenges, and minor variants can be detected. The exception is the fate of the anterior cell, P3.p, which is sensitive to stochastic variation and spontaneous mutation, and is also evolving the fastest. Other vulval precursor cell fates can be affected by mutation, yet little natural variation can be found, suggesting stabilizing selection. Despite this fate pattern conservation, different Caenorhabditis species respond differently to perturbations of the system. In the quantitative models, different parameter sets can reconstitute their response to perturbation, suggesting that network variation among Caenorhabditis species may be quantitative. Network rewiring likely occurred at longer evolutionary scales.

  2. 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, ...

  3. 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.

  4. 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.

  5. Microfluidic platforms for plant cells studies.

    Science.gov (United States)

    Sanati Nezhad, A

    2014-09-07

    Conventional methods of plant cell analysis rely on growing plant cells in soil pots or agarose plates, followed by screening the plant phenotypes in traditional greenhouses and growth chambers. These methods are usually costly, need a large number of experiments, suffer from low spatial resolution and disorderly growth behavior of plant cells, with lack of ability to locally and accurately manipulate the plant cells. Microfluidic platforms take advantage of miniaturization for handling small volume of liquids and providing a closed environment, with the purpose of in vitro single cell analysis and characterizing cell response to external cues. These platforms have shown their ability for high-throughput cellular analysis with increased accuracy of experiments, reduced cost and experimental times, versatility in design, ability for large-scale and combinatorial screening, and integration with other miniaturized sensors. Despite extensive research on animal cells within microfluidic environments for high-throughput sorting, manipulation and phenotyping studies, the application of microfluidics for plant cells studies has not been accomplished yet. Novel devices such as RootChip, RootArray, TipChip, and PlantChip developed for plant cells analysis, with high spatial resolution on a micrometer scale mimicking the internal microenvironment of plant cells, offering preliminary results on the capability of microfluidics to conquer the constraints of conventional methods. These devices have been used to study different aspects of plant cell biology such as gene expression, cell biomechanics, cellular mechanism of growth, cell division, and cells fusion. This review emphasizes the advantages of current microfluidic systems for plant science studies, and discusses future prospects of microfluidic platforms for characterizing plant cells response to diverse external cues.

  6. Geographic patterns of endemic seed plant genera diversity in China

    OpenAIRE

    Shengbin Chen; Zhiyun Ouyang; Yu Fang; Zhenji Li

    2011-01-01

    Endemism describes the phenomenon that the distribution of individual species/taxa is critically restricted to a specific region. Seed plant genera endemic to China (endemic genera) are those with their main geographic distribution range within the borders of China. The geographic patterns of endemic genera can not only guide conservation planning, but these organisms are also important biological resources. We gath-ered data of 173 localities on environmental and spatial factors, and regiona...

  7. Phylogenomic analysis demonstrates a pattern of rare and ancient horizontal gene transfer between plants and fungi.

    Science.gov (United States)

    Richards, Thomas A; Soanes, Darren M; Foster, Peter G; Leonard, Guy; Thornton, Christopher R; Talbot, Nicholas J

    2009-07-01

    Horizontal gene transfer (HGT) describes the transmission of genetic material across species boundaries and is an important evolutionary phenomenon in the ancestry of many microbes. The role of HGT in plant evolutionary history is, however, largely unexplored. Here, we compare the genomes of six plant species with those of 159 prokaryotic and eukaryotic species and identify 1689 genes that show the highest similarity to corresponding genes from fungi. We constructed a phylogeny for all 1689 genes identified and all homolog groups available from the rice (Oryza sativa) genome (3177 gene families) and used these to define 14 candidate plant-fungi HGT events. Comprehensive phylogenetic analyses of these 14 data sets, using methods that account for site rate heterogeneity, demonstrated support for nine HGT events, demonstrating an infrequent pattern of HGT between plants and fungi. Five HGTs were fungi-to-plant transfers and four were plant-to-fungi HGTs. None of the fungal-to-plant HGTs involved angiosperm recipients. These results alter the current view of organismal barriers to HGT, suggesting that phagotrophy, the consumption of a whole cell by another, is not necessarily a prerequisite for HGT between eukaryotes. Putative functional annotation of the HGT candidate genes suggests that two fungi-to-plant transfers have added phenotypes important for life in a soil environment. Our study suggests that genetic exchange between plants and fungi is exceedingly rare, particularly among the angiosperms, but has occurred during their evolutionary history and added important metabolic traits to plant lineages.

  8. Physiological functions of plant cell coverings.

    Science.gov (United States)

    Hoson, Takayuki

    2002-08-01

    The cell coverings of plants have two important functions in plant life. Plant cell coverings are deeply involved in the regulation of the life cycle of plants: each stage of the life cycle, such as germination, vegetative growth, reproductive growth, and senescence, is strongly influenced by the nature of the cell coverings. Also, the apoplast, which consists of the cell coverings, is the field where plant cells first encounter the outer environment, and so becomes the major site of plant responses to the environment. In the regulation of each stage of the life cycle and the response to each environmental signal, some specific constituents of the cell coverings, such as xyloglucans in dicotyledons and 1,3,1,4-beta-glucans in Gramineae, act as the key component. The physiological functions of plant cell coverings are sustained by the metabolic turnover of these components. The components of the cell coverings are supplied from the symplast, but then they are modified or degraded in the apoplast. Thus, the metabolism of the cell coverings is regulated through the cross-talk between the symplast and the apoplast. The understanding of physiological functions of plant cell coverings will be greatly advanced by the use of genomic approaches. At the same time, we need to introduce nanobiological techniques for clarifying the minute changes in the cell coverings that occur in a small part within each cell.

  9. Cell cycle activation by plant parasitic nematodes

    NARCIS (Netherlands)

    Goverse, A.; Almeida Engler, de J.; Verhees, J.; Krol, van der S.; Helder, J.; Gheysen, G.

    2000-01-01

    Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)differentiation includes the reactivation of the cell cycle in specific plan

  10. Spiral Phyllotaxis Pattern in an Animal Cell: A Fluid- Driven Mechanism for Red Cell Echinocytosis and Programmed Cell Death

    OpenAIRE

    Lofthouse, J. T.

    2004-01-01

    This paper demonstrates that the pattern of lipid spiculesthat emerge on the surface of red blood cells in the classic 'Discocyte to Echinocyte' shape change is a generative spiral, and presents a qualitative, fluid- driven mechanism for their production, compatible with the work of Douady and Couder. Implications for the dynamics of cell growth, plant cell phyllotaxy, programmed cell death and gravity sensitivity are explained in terms of a new qualitative model of cellular fluid dynamics.

  11. Photovoltaic cell with nano-patterned substrate

    Science.gov (United States)

    Cruz-Campa, Jose Luis; Zhou, Xiaowang; Zubia, David

    2016-10-18

    A photovoltaic solar cell comprises a nano-patterned substrate layer. A plurality of nano-windows are etched into an intermediate substrate layer to form the nano-patterned substrate layer. The nano-patterned substrate layer is positioned between an n-type semiconductor layer composed of an n-type semiconductor material and a p-type semiconductor layer composed of a p-type semiconductor material. Semiconductor material accumulates in the plurality of nano-windows, causing a plurality of heterojunctions to form between the n-type semiconductor layer and the p-type semiconductor layer.

  12. Cell patterning by laser-assisted bioprinting.

    Science.gov (United States)

    Devillard, Raphaël; Pagès, Emeline; Correa, Manuela Medina; Kériquel, Virginie; Rémy, Murielle; Kalisky, Jérôme; Ali, Muhammad; Guillotin, Bertrand; Guillemot, Fabien

    2014-01-01

    The aim of tissue engineering is to produce functional three-dimensional (3D) tissue substitutes. Regarding native organ and tissue complexity, cell density and cell spatial 3D organization, which influence cell behavior and fate, are key parameters in tissue engineering. Laser-Assisted Bioprinting (LAB) allows one to print cells and liquid materials with a cell- or picoliter-level resolution. Thus, LAB seems to be an emerging and promising technology to fabricate tissue-like structures that have the physiological functionality of their native counterparts. This technology has additional advantages such as automation, reproducibility, and high throughput. It makes LAB compatible with the (industrial) fabrication of 3D constructs of physiologically relevant sizes. Here we present exhaustively the numerous steps that allow printing of viable cells with a well-preserved micrometer pattern. To facilitate the understanding of the whole cell patterning experiment using LAB, it is discussed in two parts: (1) preprocessing: laser set-up, bio-ink cartridge and bio-paper preparation, and pattern design; and (2) processing: bio-ink printing on the bio-paper.

  13. 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.

  14. Longitudinal zonation pattern in plant roots: conflicts and solutions.

    Science.gov (United States)

    Ivanov, Victor B; Dubrovsky, Joseph G

    2013-05-01

    Despite the relative simplicity of Arabidopsis root organization, there is no general agreement regarding the terminology used to describe the longitudinal zonation pattern (LZP) of this model system. In this opinion article, we examine inconsistencies in the terminology and provide a conceptual framework for the LZP that may be applied to all angiosperms. We propose that the root apical meristem (RAM) consists of the cell-proliferation domain where cells maintain a high probability to divide and the transition domain with a low probability of cell division; in both domains cells grow at the same, relatively low, rate. Owing to stochastic termination of cell proliferation in the RAM, the border between the domains is 'fuzzy'. Molecular markers analyzed together with quantitative growth and cell analyses could help to identify developmental zones along the root and lead to a better understanding of the LZP in angiosperms.

  15. [On plant stem cells and animal stem cells].

    Science.gov (United States)

    You, Yun; Jiang, Chao; Huang, Lu-Qi

    2014-01-01

    A comparison of plant and animal stem cells can highlight core aspects of stem-cell biology. In both kingdoms, stem cells are defined by their clonogenic properties and are maintained by intercellular signals. The signaling molecules are different in plants and animals stem cell niches, but the roles of argonaute and polycomb group proteins suggest that there are some molecular similarities.

  16. Morphological classification of plant cell deaths

    DEFF Research Database (Denmark)

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

    2011-01-01

    the classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term 'apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death......Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about......, the 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...

  17. Catalysts of plant cell wall loosening

    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...

  18. [Genetic regulation of plant shoot stem cells].

    Science.gov (United States)

    Al'bert, E V; Ezhova, T A

    2013-02-01

    This article describes the main features of plant stem cells and summarizes the results of studies of the genetic control of stem cell maintenance in the apical meristem of the shoot. It is demonstrated that the WUS-CLV gene system plays a key role in the maintenance of shoot apical stem cells and the formation of adventitious buds and somatic embryos. Unconventional concepts of plant stem cells are considered.

  19. 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.

  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. Voronoi cell patterns: Theoretical model and applications

    Science.gov (United States)

    González, Diego Luis; Einstein, T. L.

    2011-11-01

    We use a simple fragmentation model to describe the statistical behavior of the Voronoi cell patterns generated by a homogeneous and isotropic set of points in 1D and in 2D. In particular, we are interested in the distribution of sizes of these Voronoi cells. Our model is completely defined by two probability distributions in 1D and again in 2D, the probability to add a new point inside an existing cell and the probability that this new point is at a particular position relative to the preexisting point inside this cell. In 1D the first distribution depends on a single parameter while the second distribution is defined through a fragmentation kernel; in 2D both distributions depend on a single parameter. The fragmentation kernel and the control parameters are closely related to the physical properties of the specific system under study. We use our model to describe the Voronoi cell patterns of several systems. Specifically, we study the island nucleation with irreversible attachment, the 1D car-parking problem, the formation of second-level administrative divisions, and the pattern formed by the Paris Métro stations.

  2. Plant cells: immobilization and oxygen transfer.

    NARCIS (Netherlands)

    Hulst, A.C.

    1987-01-01

    The study described in this thesis is part of the integrated project 'Biotechnological production of non-persistent bioinsecticides by means of plant cells invitro ' and was done in close cooperation with the research Institute Ital within the framework of NOVAPLANT. The plant cells us

  3. Cell fusion and nuclear fusion in plants.

    Science.gov (United States)

    Maruyama, Daisuke; Ohtsu, Mina; Higashiyama, Tetsuya

    2016-12-01

    Eukaryotic cells are surrounded by a plasma membrane and have a large nucleus containing the genomic DNA, which is enclosed by a nuclear envelope consisting of the outer and inner nuclear membranes. Although these membranes maintain the identity of cells, they sometimes fuse to each other, such as to produce a zygote during sexual reproduction or to give rise to other characteristically polyploid tissues. Recent studies have demonstrated that the mechanisms of plasma membrane or nuclear membrane fusion in plants are shared to some extent with those of yeasts and animals, despite the unique features of plant cells including thick cell walls and intercellular connections. Here, we summarize the key factors in the fusion of these membranes during plant reproduction, and also focus on "non-gametic cell fusion," which was thought to be rare in plant tissue, in which each cell is separated by a cell wall.

  4. 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.

  5. 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

  6. Enzymatic Modification of Plant Cell Wall Polysaccharides

    DEFF Research Database (Denmark)

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

    2011-01-01

    fibres, hydrocolloids, paper,textile, animal feeds or biofuels. Classical microbial-based fermentation systems could in the future face serious competition from plant-based expression systems for enzyme production. Plant expressed enzymes can either be targeted to specific cellular compartments......Plant cell walls are intricate structures with remarkable properties, widely used in almost every aspect of our life. Cell walls consist largely of complex polysaccharides and there is often a need for chemical and biochemical processing before industrial use. There is an increasing demand...... for sustainable processes that replace chemical treatments with white biotechnology. Plants can contribute significantly to this sustainable process by producing plant or microbialenzymes in planta that are necessary for plant cell wall modification or total degradation. This will give rise to superior food...

  7. Patterning bacterial communities on epithelial cells.

    Directory of Open Access Journals (Sweden)

    Mohammed Dwidar

    Full Text Available Micropatterning of bacteria using aqueous two phase system (ATPS enables the localized culture and formation of physically separated bacterial communities on human epithelial cell sheets. This method was used to compare the effects of Escherichia coli strain MG1655 and an isogenic invasive counterpart that expresses the invasin (inv gene from Yersinia pseudotuberculosis on the underlying epithelial cell layer. Large portions of the cell layer beneath the invasive strain were killed or detached while the non-invasive E. coli had no apparent effect on the epithelial cell layer over a 24 h observation period. In addition, simultaneous testing of the localized effects of three different bacterial species; E. coli MG1655, Shigella boydii KACC 10792 and Pseudomonas sp DSM 50906 on an epithelial cell layer is also demonstrated. The paper further shows the ability to use a bacterial predator, Bdellovibriobacteriovorus HD 100, to selectively remove the E. coli, S. boydii and P. sp communities from this bacteria-patterned epithelial cell layer. Importantly, predation and removal of the P. Sp was critical for maintaining viability of the underlying epithelial cells. Although this paper focuses on a few specific cell types, the technique should be broadly applicable to understand a variety of bacteria-epithelial cell interactions.

  8. Auditory hair cell innervational patterns in lizards.

    Science.gov (United States)

    Miller, M R; Beck, J

    1988-05-22

    The pattern of afferent and efferent innervation of two to four unidirectional (UHC) and two to nine bidirectional (BHC) hair cells of five different types of lizard auditory papillae was determined by reconstruction of serial TEM sections. The species studies were Crotaphytus wislizeni (iguanid), Podarcis (Lacerta) sicula and P. muralis (lacertids), Ameiva ameiva (teiid), Coleonyx variegatus (gekkonid), and Mabuya multifasciata (scincid). The main object was to determine in which species and in which hair cell types the nerve fibers were innervating only one (exclusive innervation), or two or more hair cells (nonexclusive innervation); how many nerve fibers were supplying each hair cell; how many synapses were made by the innervating fibers; and the total number of synapses on each hair cell. In the species studies, efferent innervation was limited to the UHC, and except for the iguanid, C. wislizeni, it was nonexclusive, each fiber supplying two or more hair cells. Afferent innervation varied both with the species and the hair cell types. In Crotaphytus, both the UHC and the BHC were exclusively innervated. In Podarcis and Ameiva, the UHC were innervated exclusively by some fibers but nonexclusively by others (mixed pattern). In Coleonyx, the UHC were exclusively innervated but the BHC were nonexclusively innervated. In Mabuya, both the UHC and BHC were nonexclusively innervated. The number of afferent nerve fibers and the number of afferent synapses were always larger in the UHC than in the BHC. In Ameiva, Podarcis, and Mabuya, groups of bidirectionally oriented hair cells occur in regions of cytologically distinct UHC, and in Ameiva, unidirectionally oriented hair cells occur in cytologically distinct BHC regions.

  9. Extracellular ATP acts as a damage associated molecular pattern (DAMP signal in plants

    Directory of Open Access Journals (Sweden)

    Kiwamu eTanaka

    2014-09-01

    Full Text Available As sessile organisms, plants have evolved effective mechanisms to protect themselves from environmental stresses. Damaged (i.e., wounded plants recognize a variety of endogenous molecules as danger signals, referred to as damage-associated molecular patterns (DAMPs. ATP is among the molecules that are released by cell damage, and recent evidence suggests that ATP can serve as a DAMP. Although little studied in plants, extracellular ATP is well known for its signaling role in animals, including acting as a DAMP during the inflammatory response and wound healing. If ATP acts outside the cell, then it is reasonable to expect that it is recognized by a plasma membrane-localized receptor. Recently, DORN1, a lectin receptor kinase, was shown to recognize extracellular ATP in Arabidopsis. DORN1 is the founding member of a new purinoceptor subfamily, P2K (P2 receptor Kinase, which is plant-specific. P2K1 (DORN1 is required for ATP-induced cellular responses (e.g., cytosolic Ca2+ elevation, MAPK phosphorylation, and gene expression. Genetic analysis of loss-of-function mutants and overexpression lines showed that P2K1 participates in the plant wound response, consistent with the role of ATP as a DAMP. In this review, we summarize past research on the roles and mechanisms of extracellular ATP signaling in plants, and discuss the direction of the future research of extracellular ATP as a DAMP signal.

  10. Plant cell proliferation inside an inorganic host.

    Science.gov (United States)

    Perullini, Mercedes; Rivero, María Mercedes; Jobbágy, Matías; Mentaberry, Alejandro; Bilmes, Sara A

    2007-01-10

    In recent years, much attention has been paid to plant cell culture as a tool for the production of secondary metabolites and the expression of recombinant proteins. Plant cell immobilization offers many advantages for biotechnological processes. However, the most extended matrices employed, such as calcium-alginate, cannot fully protect entrapped cells. Sol-gel chemistry of silicates has emerged as an outstanding strategy to obtain biomaterials in which living cells are truly protected. This field of research is rapidly developing and a large number of bacteria and yeast-entrapping ceramics have already been designed for different applications. But even mild thermal and chemical conditions employed in sol-gel synthesis may result harmful to cells of higher organisms. Here we present a method for the immobilization of plant cells that allows cell growth at cavities created inside a silica matrix. Plant cell proliferation was monitored for a 6-month period, at the end of which plant calli of more than 1 mm in diameter were observed inside the inorganic host. The resulting hybrid device had good mechanical stability and proved to be an effective barrier against biological contamination, suggesting that it could be employed for long-term plant cell entrapment applications.

  11. Host-induced bacterial cell wall decomposition mediates pattern-triggered immunity in Arabidopsis.

    Science.gov (United States)

    Liu, Xiaokun; Grabherr, Heini M; Willmann, Roland; Kolb, Dagmar; Brunner, Frédéric; Bertsche, Ute; Kühner, Daniel; Franz-Wachtel, Mirita; Amin, Bushra; Felix, Georg; Ongena, Marc; Nürnberger, Thorsten; Gust, Andrea A

    2014-06-23

    Peptidoglycans (PGNs) are immunogenic bacterial surface patterns that trigger immune activation in metazoans and plants. It is generally unknown how complex bacterial structures such as PGNs are perceived by plant pattern recognition receptors (PRRs) and whether host hydrolytic activities facilitate decomposition of bacterial matrices and generation of soluble PRR ligands. Here we show that Arabidopsis thaliana, upon bacterial infection or exposure to microbial patterns, produces a metazoan lysozyme-like hydrolase (lysozyme 1, LYS1). LYS1 activity releases soluble PGN fragments from insoluble bacterial cell walls and cleavage products are able to trigger responses typically associated with plant immunity. Importantly, LYS1 mutant genotypes exhibit super-susceptibility to bacterial infections similar to that observed on PGN receptor mutants. We propose that plants employ hydrolytic activities for the decomposition of complex bacterial structures, and that soluble pattern generation might aid PRR-mediated immune activation in cell layers adjacent to infection sites.

  12. Behind the lines–actions of bacterial type III effector proteins in plant cells

    OpenAIRE

    Büttner, Daniela

    2016-01-01

    Pathogenicity of most Gram-negative plant-pathogenic bacteria depends on the type III secretion (T3S) system, which translocates bacterial effector proteins into plant cells. Type III effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. One major virulence function of type III effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. Ty...

  13. Effect of density and planting pattern on yield and yield

    Directory of Open Access Journals (Sweden)

    alireza yadavi

    2009-06-01

    Full Text Available In order to evaluate competition ability of Grain maize (Zea mays L. against redroot pigweed (Amaranthus retroflexus L. a field experiment was conducted at Esfahan on 2003. In this research the effect of corn spatial arrangement on yield and yield components of corn (647 Three Way Cross hybrids under different levels of redroot pigweed infestation was investigated. Treatments were arranged in a factorial split experiment based on RCBD with three replications. Factorial arrangement of corn densities (74000 and 111000 plant ha-1 and planting patterns (single row, rectangular twin row and zigzag twin row formed the main plots. Split-plots referred to pigweed densities (0, 4, 8 and 12 plant m-1. Results showed that both grain and biological yield of corn increased as corn density rates increased but rows number per cob, number of grains per row of cob and 1000 grains weight decreased. The effects of planting arrangement on yield and yield components despite rows grain in cob, 1000 seeds weight and harvest index were statistically significant. Corn grain yield and yield components decreased significantly by increasing pigweed density. The effect of redroot pigweed density on corn grain and biological yield loss was predicted using Cousence hyperbolic yield equation. It showed that maximum grain yield loss and biological yield loss happened in single row arrangement and low corn density. Rows number per cob and grain numbers per row in higher corn density treatment showed lower reduction slopes under pigweed competition. In addition, grain rows numbers per cob and corn harvest index in twin arrangement treatments decreased lower than single row treatment under pigweed competition. The results of this research indicated that corn competition ability against redroot pigweed could be increased using dense population (1/5 fold of general density and zigzag twin row arrangement.

  14. 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.

  15. DIRECT FUEL/CELL/TURBINE POWER PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Hossein Ghezel-Ayagh

    2004-05-01

    This report includes the progress in development of Direct FuelCell/Turbine{reg_sign} (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation 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, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide release to the environment, and potential cost competitiveness with existing combined cycle power plants. FCE successfully completed testing of the pre-alpha DFC/T hybrid power plant. This power plant was constructed by integration of a 250kW fuel cell stack and a microturbine. The tests of the cascaded fuel cell concept for achieving high fuel utilizations were completed. The tests demonstrated that the concept results in higher power plant efficiency. Also, the preliminary design of a 40 MW power plant including the key equipment layout and the site plan was completed.

  16. Disposable Bioreactors for Plant Micropropagation and Mass Plant Cell Culture

    Science.gov (United States)

    Ducos, Jean-Paul; Terrier, Bénédicte; Courtois, Didier

    Different types of bioreactors are used at Nestlé R&D Centre - Tours for mass propagation of selected plant varieties by somatic embryogenesis and for large scale culture of plants cells to produce metabolites or recombinant proteins. Recent studies have been directed to cut down the production costs of these two processes by developing disposable cell culture systems. Vegetative propagation of elite plant varieties is achieved through somatic embryogenesis in liquid medium. A pilot scale process has recently been set up for the industrial propagation of Coffea canephora (Robusta coffee). The current production capacity is 3.0 million embryos per year. The pre-germination of the embryos was previously conducted by temporary immersion in liquid medium in 10-L glass bioreactors. An improved process has been developed using a 10-L disposable bioreactor consisting of a bag containing a rigid plastic box ('Box-in-Bag' bioreactor), insuring, amongst other advantages, a higher light transmittance to the biomass due to its horizontal design. For large scale cell culture, two novel flexible plastic-based disposable bioreactors have been developed from 10 to 100 L working volumes, validated with several plant species ('Wave and Undertow' and 'Slug Bubble' bioreactors). The advantages and the limits of these new types of bioreactor are discussed, based mainly on our own experience on coffee somatic embryogenesis and mass cell culture of soya and tobacco.

  17. Plant cells in vitro under altered gravity.

    Science.gov (United States)

    Klymchuk, D O

    1998-07-01

    Establishing the role of gravity in plant requires information about how gravity regulates the metabolism of individual cells. Plant cells and tissues in vitro are valuable models for such purpose. Disrupted intercellular relations in such models have allowed to elucidate both the gravity role in non-specialised to gravity plant cells and the correlative relation role of an intact plant organism. The data obtained from non-numerous space and clinostat experiments with plant cells in vitro have demonstrated that their metabolism is sensitive to g-environment. The most experiments have shown a decrease in the biomass production and cell proliferation of spaceflight samples compared with ground controls, although there is study reporting of increased biomass production in an anise suspension culture and D. carota crown gall tissue culture. At the same time, results of experiments with single carrot cells and tomato callus culture demonstrated similarities in differentiation process in microgravity and in ground controls. Noted ultrastructural arrangement in cells, especially mitochondria and plastids, have been related to altered energy load and functions of organelles in microgravity, as well as changes in the lipid peroxidation and the content of malonic dyaldehyde in a haplopappus tissue culture under altered gravity supposed with modification of membrane structural-functional state. This article focuses on growth aspects of the cultured cells in microgravity and under clinostat conditions and considers those aspects that require further analysis.

  18. Dynamic metabolic flux analysis of plant cell wall synthesis.

    Science.gov (United States)

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

    2013-07-01

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

  19. Isolation of plant cell wall proteins

    OpenAIRE

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

    2007-01-01

    The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific drawbacks: (i) the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP) during the isolation procedure; (ii) polysaccharide networks of cellulose, hemicelluloses and pectins form potential traps for contaminants such as intracellular proteins; (iii) the presence of proteins ...

  20. 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.

  1. 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...

  2. Quantitative Aspects of Cyclosis in Plant Cells.

    Science.gov (United States)

    Howells, K. F.; Fell, D. A.

    1979-01-01

    Describes an exercise which is currently used in a course in cell physiology at Oxford Polytechnic in England. This exercise can give students some idea of the molecular events involved in bringing about movement of chloroplasts (and other organelles) in plant cells. (HM)

  3. Specific recognition of AVR4 and AVR9 results in distinct patterns of hypersensitive cell death in tomato, but similar patterns of defence-related gene expression

    NARCIS (Netherlands)

    Cai, X.; Takken, F.L.W.; Joosten, M.H.A.J.; Wit, De P.J.G.M.

    2001-01-01

    Hypersensitive cell death occurs in tomato seedlings that are derived from a cross between plants that express a resistance (Cf) gene against the pathogenic fungus Cladosporium fulvum and plants that contain the matching avirulence (Avr) gene originating from this fungus. The pattern of Cf-9/Avr9- a

  4. 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.

  5. Patterned Poly(dopamine) Films for Enhanced Cell Adhesion.

    Science.gov (United States)

    Chen, Xi; Cortez-Jugo, Christina; Choi, Gwan H; Björnmalm, Mattias; Dai, Yunlu; Yoo, Pil J; Caruso, Frank

    2017-01-18

    Engineered materials that promote cell adhesion and cell growth are important in tissue engineering and regenerative medicine. In this work, we produced poly(dopamine) (PDA) films with engineered patterns for improved cell adhesion. The patterned films were synthesized via the polymerization of dopamine at the air-water interface of a floating bed of spherical particles. Subsequent dissolution of the particles yielded free-standing PDA films with tunable geometrical patterns. Our results show that these patterned PDA films significantly enhance the adhesion of both cancer cells and stem cells, thus showing promise as substrates for cell attachment for various biomedical applications.

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

    DEFF Research Database (Denmark)

    Liesche, Johannes; Schulz, Alexander

    2015-01-01

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

  7. UV-Induced Cell Death in Plants

    Directory of Open Access Journals (Sweden)

    Chang Ho Kang

    2013-01-01

    Full Text Available Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm, plants are exposed to UV light, which is comprised of UV-C (below 280 nm, UV-B (280–320 nm and UV-A (320–390 nm. The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS. Arabidopsis metacaspase-8 (AtMC8 is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1 gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD.

  8. Osmosis in Poisoned Plant Cells.

    Science.gov (United States)

    Tatina, Robert

    1998-01-01

    Describes two simple laboratory exercises that allow students to test hypotheses concerning the requirement of cell energy for osmosis. The first exercise involves osmotically-caused changes in the length of potato tubers and requires detailed quantitative observations. The second exercise involves osmotically-caused changes in turgor of Elodea…

  9. Interfamily transfer of a plant pattern-recognition receptor confers broad-spectrum bacterial resistance

    NARCIS (Netherlands)

    Lacombe, S.; Rougon-Cardoso, A.; Sherwood, E.; Peeters, N.; Dahlbeck, D.; Esse, van H.P.; Smoker, M.; Rallapalli, G.; Thomma, B.P.H.J.; Staskawicz, B.; Jones, J.D.G.; Zipfel, C.

    2010-01-01

    Plant diseases cause massive losses in agriculture. Increasing the natural defenses of plants may reduce the impact of phytopathogens on agricultural productivity. Pattern-recognition receptors (PRRs) detect microbes by recognizing conserved pathogen-associated molecular patterns (PAMPs)1, 2, 3. Alt

  10. Control of the actin cytoskeleton in plant cell growth

    NARCIS (Netherlands)

    Hussey, P.J.; Ketelaar, M.J.; Deeks, M.J.

    2006-01-01

    Plant cells grow through increases in volume and cell wall surface area. The mature morphology of a plant cell is a product of the differential rates of expansion between neighboring zones of the cell wall during this process. Filamentous actin arrays are associated with plant cell growth, and the a

  11. Cell-fate specification in the epidermis: a common patterning mechanism in the root and shoot.

    Science.gov (United States)

    Schiefelbein, John

    2003-02-01

    The specification of epidermal hairs in Arabidopsis provides a useful model for the study of pattern formation in plants. Although the distributions of hair cells in the root and shoot appear quite different, recent studies show that pattern formation in each relies on a common cassette of transcriptional regulators. During development in each organ, neighboring cells compete to express regulators that specify the primary cell fate (including WEREWOLF [WER]/GLABRA1 [GL1], GL3/bHLH, TRANSPARENT TESTA GLABRA [TTG], and GL2), as well as those that prevent their neighbors from adopting this fate (including CAPRICE [CPC] and TRIPTYCHON [TRY]). The basic mechanism of lateral inhibition with feedback that has been uncovered by recent studies provides a conceptual framework for understanding how patterns of cell fate in general may be specified during plant development.

  12. Recent advances in plant cell wall proteomics.

    Science.gov (United States)

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

    2008-02-01

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

  13. Spectro-Microscopy of Living Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Klaus Harter; Alfred J. Meixner; Frank Schleifenbaum

    2012-01-01

    Spectro-microscopy,a combination of fluorescence microscopy with spatially resolved spectroscopic techniques,provides new and exciting tools for functional cell biology in living organisms.This review focuses on recent developments in spectro-microscopic applications for the investigation of living plant cells in their native tissue context.The application of spectro-microscopic methods led to the recent discovery of a fast signal response pathway for the brassinosteroide receptor BRI1 in the plasma membrane of living plant cells.Moreover,the competence of different plant cell types to respond to environmental or endogenous stimuli was determined in vivo by correlation analysis of different optical and spectroscopic readouts such as fluorescence lifetime (FLT).Furthermore,a new spectro-microscopic technique,fluorescence intensity decay shape analysis microscopy (FIDSAM),has been developed.FIDSAM is capable of imaging lowexpressed fluorophore-tagged proteins at high spatial resolution and precludes the misinterpretation of autofluorescence artifacts.In addition,FIDSAM provides a very effective and sensitive tool on the basis of F(o)rster resonance energy transfer (FRET) for the qualitative and quantitative determination of protein-protein interaction.Finally,we report on the quantitative analysis of the photosystem Ⅰ and Ⅱ (PSⅠ/PSⅡ) ratio in the chloroplasts of living Arabidopsis plants at room temperature,using high-resolution,spatially resolved fluorescence spectroscopy.With this technique,it was not only possible to measure PSⅠ/PSⅡ ratios,but also to demonstrate the differential competence of wild-type and carbohydrate-deficient plants to adapt the PSⅠ/PSⅡ ratio to different light conditions.In summary,the information content of standard microscopic images is extended by several dimensions by the use of spectro-microscopic approaches.Therefore,novel cell physiological and molecular topics can be addressed and valuable insights into molecular and

  14. A Versatile Method of Patterning Proteins and Cells.

    Science.gov (United States)

    Shrirao, Anil B; Kung, Frank H; Yip, Derek; Firestein, Bonnie L; Cho, Cheul H; Townes-Anderson, Ellen

    2017-02-26

    Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.

  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. Plant microbial fuel cell applied in wetlands

    NARCIS (Netherlands)

    Wetser, Koen; Liu, Jia; Buisman, Cees; Strik, David

    2015-01-01

    The plant microbial fuel cell (PMFC) has to be applied in wetlands to be able to generate electricity on a large scale. The objective of this PMFC application research is to clarify the differences in electricity generation between a Spartina anglica salt marsh and Phragmites australis peat soil

  17. 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,...

  18. 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.

  19. Fluorescence activated cell sorting of plant protoplasts.

    Science.gov (United States)

    Bargmann, Bastiaan O R; Birnbaum, Kenneth D

    2010-02-18

    High-resolution, cell type-specific analysis of gene expression greatly enhances understanding of developmental regulation and responses to environmental stimuli in any multicellular organism. In situ hybridization and reporter gene visualization can to a limited extent be used to this end but for high resolution quantitative RT-PCR or high-throughput transcriptome-wide analysis the isolation of RNA from particular cell types is requisite. Cellular dissociation of tissue expressing a fluorescent protein marker in a specific cell type and subsequent Fluorescence Activated Cell Sorting (FACS) makes it possible to collect sufficient amounts of material for RNA extraction, cDNA synthesis/amplification and microarray analysis. An extensive set of cell type-specific fluorescent reporter lines is available to the plant research community. In this case, two marker lines of the Arabidopsis thaliana root are used: P(SCR;)::GFP (endodermis and quiescent center) and P(WOX5;)::GFP (quiescent center). Large numbers (thousands) of seedlings are grown hydroponically or on agar plates and harvested to obtain enough root material for further analysis. Cellular dissociation of plant material is achieved by enzymatic digestion of the cell wall. This procedure makes use of high osmolarity-induced plasmolysis and commercially available cellulases, pectinases and hemicellulases to release protoplasts into solution. FACS of GFP-positive cells makes use of the visualization of the green versus the red emission spectra of protoplasts excited by a 488 nm laser. GFP-positive protoplasts can be distinguished by their increased ratio of green to red emission. Protoplasts are typically sorted directly into RNA extraction buffer and stored for further processing at a later time. This technique is revealed to be straightforward and practicable. Furthermore, it is shown that it can be used without difficulty to isolate sufficient numbers of cells for transcriptome analysis, even for very scarce

  20. Automatic micropropagation of plants--the vision-system: graph rewriting as pattern recognition

    Science.gov (United States)

    Schwanke, Joerg; Megnet, Roland; Jensch, Peter F.

    1993-03-01

    The automation of plant-micropropagation is necessary to produce high amounts of biomass. Plants have to be dissected on particular cutting-points. A vision-system is needed for the recognition of the cutting-points on the plants. With this background, this contribution is directed to the underlying formalism to determine cutting-points on abstract-plant models. We show the usefulness of pattern recognition by graph-rewriting along with some examples in this context.

  1. 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

  2. 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.

  3. Plant thin cell layers: update and perspectives

    Directory of Open Access Journals (Sweden)

    Teixeira da Silva Jaime A.

    2015-12-01

    Full Text Available Thin cell layers (TCLs are small and versatile explants for the in vitro culture of plants. At face value, their morphogenic productivity may appear to be less than conventional explants, but once the plant growth correction factor and geometric factor have been applied, the true (potential productivity exceeds that of a conventional explant. It is for this reason that for almost 45 years, TCLs have been applied to the in vitro culture of almost 90 species or hybrids, mainly ornamentals and orchids, but also to field and vegetable crops and medicinal plants. Focusing on 12 new studies that have emerged in the recent past (2013-2015, this paper brings promise to other horticultural species that could benefit from the use of TCLs.

  4. Isolation of plant cell wall proteins.

    Science.gov (United States)

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

    2008-01-01

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

  5. Behind the lines–actions of bacterial type III effector proteins in plant cells

    Science.gov (United States)

    Büttner, Daniela

    2016-01-01

    Pathogenicity of most Gram-negative plant-pathogenic bacteria depends on the type III secretion (T3S) system, which translocates bacterial effector proteins into plant cells. Type III effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. One major virulence function of type III effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. Type III effectors also interfere with additional plant cellular processes including proteasome-dependent protein degradation, phytohormone signaling, the formation of the cytoskeleton, vesicle transport and gene expression. This review summarizes our current knowledge on the molecular functions of type III effector proteins with known plant target molecules. Furthermore, plant defense strategies for the detection of effector protein activities or effector-triggered alterations in plant targets are discussed. PMID:27526699

  6. Soil microbes contribute to the classic plant diversity-productivity pattern

    NARCIS (Netherlands)

    Schnitzer, S.A.; Klironomos, J.N.; HilleRisLambers, J.; Kinkel, L.L.; Reich, P.B.; Nes, van E.H.; Scheffer, M.

    2011-01-01

    Ecosystem productivity commonly increases asymptotically with plant species diversity, and determining the mechanisms responsible for this well-known pattern is essential to predict potential changes in ecosystem productivity with ongoing species loss. Previous studies attributed the asymptotic dive

  7. Developmentally regulated epitopes of cell surface arabinogalactan proteins and their relation to root tissue pattern formation.

    Science.gov (United States)

    Knox, J P; Linstead, P J; Peart, J; Cooper, C; Roberts, K

    1991-11-01

    Two polymorphic forms of an extracellular arabinogalactan protein (AGP1 and AGP2), obtained from the conditioned media of two carrot suspension-cultured cell lines, have been identified in terms of binding of the anti-plasma membrane antibodies JIM4 and MAC207. AGP1 and AGP2 have been used as immunogens to generate further anti-AGP monoclonal antibodies. JIM14 identified an epitope carried by AGP2 and also by glycoproteins of low molecular weight localized to the plant cell wall. In addition, further antibodies (JIM13 and JIM15) identified carbohydrate epitopes of the AGPs that also occur on plasma membrane glycoproteins and are expressed by patterns of cells that reflect cell position at the carrot root apex. Indirect immunofluorescence microscopy indicated that JIM13 recognized the surface of cells forming the epidermis and cells marking the region and axis of the future xylem. JIM15 recognized a pattern of cells directly complementary to the JIM13 pattern. The panel of anti-AGP monoclonal antibodies now available indicates groups of cells within the root meristem that may reflect an early pre-pattern of the tissues of the mature root structure and suggests extensive modulation of cell surface AGPs during cell development and the positioning of cells within the apex.

  8. Pattern matching and adaptive image segmentation applied to plant reproduction by tissue culture

    Science.gov (United States)

    Vazquez Rueda, Martin G.; Hahn, Federico

    1999-03-01

    This paper shows the results obtained in a system vision applied to plant reproduction by tissue culture using adaptive image segmentation and pattern matching algorithms, this analysis improves the number of tissue obtained and minimize errors, the image features of tissue are considered join to statistical analysis to determine the best match and results. Tests make on potato plants are used to present comparative results with original images processed with adaptive segmentation algorithm and non adaptive algorithms and pattern matching.

  9. 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.

  10. The potential of single-cell profiling in plants.

    Science.gov (United States)

    Efroni, Idan; Birnbaum, Kenneth D

    2016-04-05

    Single-cell transcriptomics has been employed in a growing number of animal studies, but the technique has yet to be widely used in plants. Nonetheless, early studies indicate that single-cell RNA-seq protocols developed for animal cells produce informative datasets in plants. We argue that single-cell transcriptomics has the potential to provide a new perspective on plant problems, such as the nature of the stem cells or initials, the plasticity of plant cells, and the extent of localized cellular responses to environmental inputs. Single-cell experimental outputs require different analytical approaches compared with pooled cell profiles and new tools tailored to single-cell assays are being developed. Here, we highlight promising new single-cell profiling approaches, their limitations as applied to plants, and their potential to address fundamental questions in plant biology.

  11. 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.

  12. Eco-geophysical imaging of watershed-scale soil patterns links with plant community spatial patterns

    Science.gov (United States)

    The extent to which soil resource availability, nutrients or 1 moisture, control the structure, function and diversity of plant communities has aroused considerable interest in the past decade, and remains topical in light of global change. Numerous plant communities are controlled either by water o...

  13. Interfamily transfer of a plant pattern-recognition receptor confers broad-spectrum bacterial resistance.

    Science.gov (United States)

    Lacombe, Séverine; Rougon-Cardoso, Alejandra; Sherwood, Emma; Peeters, Nemo; Dahlbeck, Douglas; van Esse, H Peter; Smoker, Matthew; Rallapalli, Ghanasyam; Thomma, Bart P H J; Staskawicz, Brian; Jones, Jonathan D G; Zipfel, Cyril

    2010-04-01

    Plant diseases cause massive losses in agriculture. Increasing the natural defenses of plants may reduce the impact of phytopathogens on agricultural productivity. Pattern-recognition receptors (PRRs) detect microbes by recognizing conserved pathogen-associated molecular patterns (PAMPs). Although the overall importance of PAMP-triggered immunity for plant defense is established, it has not been used to confer disease resistance in crops. We report that activity of a PRR is retained after its transfer between two plant families. Expression of EFR (ref. 4), a PRR from the cruciferous plant Arabidopsis thaliana, confers responsiveness to bacterial elongation factor Tu in the solanaceous plants Nicotiana benthamiana and tomato (Solanum lycopersicum), making them more resistant to a range of phytopathogenic bacteria from different genera. Our results in controlled laboratory conditions suggest that heterologous expression of PAMP recognition systems could be used to engineer broad-spectrum disease resistance to important bacterial pathogens, potentially enabling more durable and sustainable resistance in the field.

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

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao

    2012-01-01

    Beta diversity (i.e. species turnover rate across space) is fundamental for understanding mechanisms controlling large-scale species richness patterns. However, the influences on beta diversity are still a matter of debate. In particular, the relative role of environmental and spatial processes (...

  15. 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.

  16. Cell polarity in plants: when two do the same, it is not the same....

    Science.gov (United States)

    Dettmer, Jan; Friml, Jiří

    2011-12-01

    In unicellular and multicellular organisms, cell polarity is essential for a wide range of biological processes. An important feature of cell polarity is the asymmetric distribution of proteins in or at the plasma membrane. In plants such polar localized proteins play various specific roles ranging from organizing cell morphogenesis, asymmetric cell division, pathogen defense, nutrient transport and establishment of hormone gradients for developmental patterning. Moreover, flexible respecification of cell polarities enables plants to adjust their physiology and development to environmental changes. Having evolved multicellularity independently and lacking major cell polarity mechanisms of animal cells, plants came up with alternative solutions to generate and respecify cell polarity as well as to regulate polar domains at the plasma membrane.

  17. 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.

  18. 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.

  19. A survey of cellulose microfibril patterns in dividing, expanding, and differentiating cells of Arabidopsis thaliana.

    Science.gov (United States)

    Fujita, Miki; Wasteneys, Geoffrey O

    2014-05-01

    Cellulose microfibrils are critical for plant cell specialization and function. Recent advances in live cell imaging of fluorescently tagged cellulose synthases to track cellulose synthesis have greatly advanced our understanding of cellulose biosynthesis. Nevertheless, cellulose deposition patterns remain poorly described in many cell types, including those in the process of division or differentiation. In this study, we used field emission scanning electron microscopy analysis of cryo-planed tissues to determine the arrangement of cellulose microfibrils in various faces of cells undergoing cytokinesis or specialized development, including cell types in which cellulose cannot be imaged by conventional approaches. In dividing cells, we detected microfibrillar meshworks in the cell plates, consistent with the concentration at the cell plate of cellulose synthase complexes, as detected by fluorescently tagged CesA6. We also observed a loss of parallel cellulose microfibril orientation in walls of the mother cell during cytokinesis, which corresponded with the loss of fluorescently tagged cellulose synthase complexes from these surfaces. In recently formed guard cells, microfibrils were randomly organized and only formed a highly ordered circumferential pattern after pore formation. In pit fields, cellulose microfibrils were arranged in circular patterns around plasmodesmata. Microfibrils were random in most cotyledon cells except the epidermis and were parallel to the growth axis in trichomes. Deposition of cellulose microfibrils was spatially delineated in metaxylem and protoxylem cells of the inflorescence stem, supporting recent studies on microtubule exclusion mechanisms.

  20. 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.

  1. 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

  2. The potential of single-cell profiling in plants

    OpenAIRE

    Efroni, Idan; Birnbaum, Kenneth D

    2016-01-01

    Single-cell transcriptomics has been employed in a growing number of animal studies, but the technique has yet to be widely used in plants. Nonetheless, early studies indicate that single-cell RNA-seq protocols developed for animal cells produce informative datasets in plants. We argue that single-cell transcriptomics has the potential to provide a new perspective on plant problems, such as the nature of the stem cells or initials, the plasticity of plant cells, and the extent of localized ce...

  3. Scaffold-independent Patterning of Cells using Magnetic Nanoparticles

    Science.gov (United States)

    Ghosh, Suvojit; Biswas, Moanaro; Elankumaran, Subbiah; Puri, Ishwar

    2013-03-01

    Spatial patterning of cells in vitro relies on direct contact of cells on to solid surfaces. Scaffold independent patterning of cells has never been achieved so far. Patterning of cells has wide applications including stem cell biology, tissue architecture and regenerative medicine besides fundamental biology. Magnetized cells in a suspension can be manipulated using an externally applied magnetic field enabling directed patterning. We magnetized mammalian cells by internalization of superparamagnetic nanoparticles coated with bovine serum albumin (BSA). A magnetic field is then used to arrange cells in a desired pattern on a substrate or in suspension. The control strategy is derived from the self-assembly of magnetic colloids in a liquid considering magnetostatic interactions. The range of achievable structural features promise novel experimental methods investigating the influence of tissue shape and size on cell population dynamics wherein Fickian diffusion of autocrine growth signals are known to play a significant role. By eliminating the need for a scaffold, intercellular adhesion mechanics and the effects of temporally regulated signals can be investigated. The findings can be applied to novel tissue engineering methods.

  4. Host ecology determines the dispersal patterns of a plant virus.

    Science.gov (United States)

    Trovão, Nídia Sequeira; Baele, Guy; Vrancken, Bram; Bielejec, Filip; Suchard, Marc A; Fargette, Denis; Lemey, Philippe

    2015-01-01

    Since its isolation in 1966 in Kenya, rice yellow mottle virus (RYMV) has been reported throughout Africa resulting in one of the economically most important tropical plant emerging diseases. A thorough understanding of RYMV evolution and dispersal is critical to manage viral spread in tropical areas that heavily rely on agriculture for subsistence. Phylogenetic analyses have suggested a relatively recent expansion, perhaps driven by the intensification of agricultural practices, but this has not yet been examined in a coherent statistical framework. To gain insight into the historical spread of RYMV within Africa rice cultivations, we analyse a dataset of 300 coat protein gene sequences, sampled from East to West Africa over a 46-year period, using Bayesian evolutionary inference. Spatiotemporal reconstructions date the origin of RMYV back to 1852 (1791-1903) and confirm Tanzania as the most likely geographic origin. Following a single long-distance transmission event from East to West Africa, separate viral populations have been maintained for about a century. To identify the factors that shaped the RYMV distribution, we apply a generalised linear model (GLM) extension of discrete phylogenetic diffusion and provide strong support for distances measured on a rice connectivity landscape as the major determinant of RYMV spread. Phylogeographic estimates in continuous space further complement this by demonstrating more pronounced expansion dynamics in West Africa that are consistent with agricultural intensification and extensification. Taken together, our principled phylogeographic inference approach shows for the first time that host ecology dynamics have shaped the historical spread of a plant virus.

  5. 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.``

  6. 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.

  7. Plant roots use a patterning mechanism to position lateral root branches toward available water.

    Science.gov (United States)

    Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

    2014-06-24

    The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

  8. Changes in Parthenogenetic Imprinting Patterns during Reprogramming by Cell Fusion.

    Directory of Open Access Journals (Sweden)

    Hyun Sik Jang

    Full Text Available Differentiated somatic cells can be reprogrammed into the pluripotent state by cell-cell fusion. In the pluripotent state, reprogrammed cells may then self-renew and differentiate into all three germ layers. Fusion-induced reprogramming also epigenetically modifies the somatic cell genome through DNA demethylation, X chromosome reactivation, and histone modification. In this study, we investigated whether fusion with embryonic stem cells (ESCs also reprograms genomic imprinting patterns in somatic cells. In particular, we examined imprinting changes in parthenogenetic neural stem cells fused with biparental ESCs, as well as in biparental neural stem cells fused with parthenogenetic ESCs. The resulting hybrid cells expressed the pluripotency markers Oct4 and Nanog. In addition, methylation of several imprinted genes except Peg3 was comparable between hybrid cells and ESCs. This finding indicates that reprogramming by cell fusion does not necessarily reverse the status of all imprinted genes to the state of pluripotent fusion partner.

  9. Altitudinal Pattern of Plant Species Diversity in Shennongjia Mountains, Central China

    Institute of Scientific and Technical Information of China (English)

    Chang-Ming ZHAO; Wei-Lie CHEN; Zi-Qiang TIAN; Zong-Qiang XIE

    2005-01-01

    One hundred and sixty plots, approximately every 100 m above sea level (a.s.l.) along an altitudinal gradient from 470 to 3 080 m a.s.l, at the southern and northern watershed of Mt. Shennongjia,China, were examined to determine the altitudinal pattern of plant species diversity. Mt. Shennongjia was found to have high plant species diversity, with 3 479 higher plants recorded. Partial correlation analysis and detrended canonical correspondence analysis (DCCA) based on plant species diversity revealed that altitude was the main factor affecting the spatial pattern of plant species diversity on Mt. Shennongjia and that canopy coverage of the arbor layer also had a considerable effect on plant species diversity. The DCCA based on species data of importance value further revealed that altitude gradient was the primary factor shaping the spatial pattern of plant species. In addition, the rule of the "mid-altitude bulge" was supported on Mt. Shennongjia. Plant species diversity was closely related to vegetation type and the transition zone usually had a higher diversity. Higher plant species diversity appeared in the mixed evergreen and deciduous broadleaved forest zone (900-1 500 m a.s.l.) and its transition down to evergreen broadleaved forest zone or up to deciduous broadleaved forest zone. The largest plant species diversity in whole communities on Mt. Shennongjia lay at approximately 1 200 m a.s.l. Greatest tree diversity, shrub diversity, and grass diversity was found at approximately 1 500, 1 100, and 1 200 m a.s.l., respectively. The southern watershed showed higher plant species diversity than the northern watershed, with maximum plant species diversity at a higher altitude in the southern watershed than the northern watershed. These results indicate that Mt.Shennongjia shows characteristics of a transition region. The relationship between the altitudinal pattern of plant species diversity and the vegetation type in eastern China are also discussed and a

  10. Cell pattern in the Arabidopsis root epidermis determined by lateral inhibition with feedback.

    Science.gov (United States)

    Lee, Myeong Min; Schiefelbein, John

    2002-03-01

    In the root epidermis of Arabidopsis, hair and nonhair cell types are specified in a distinct position-dependent pattern. Here, we show that transcriptional feedback loops between the WEREWOLF (WER), CAPRICE (CPC), and GLABRA2 (GL2) genes help to establish this pattern. Positional cues bias the expression of the WER MYB gene, leading to the induction of CPC and GL2 in cells located in a particular position (N) and adoption of the nonhair fate. The truncated MYB encoded by CPC mediates a lateral inhibition mechanism to negatively regulate WER, GL2, and its own gene in the alternative position (H) to induce the hair fate. These results provide a molecular genetic framework for understanding the determination of a cell-type pattern in plants.

  11. Cell cycles and proliferation patterns in Haematococcus pluvialis

    Science.gov (United States)

    Zhang, Chunhui; Liu, Jianguo; Zhang, Litao

    2016-09-01

    Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation; far less attention has been paid to cell cycles and proliferation patterns. The purpose of this study was to clarify cell cycles and proliferation patterns in H. pluvialis microscopically using a camera and video recorder system. The complicated life history of H. pluvialis can be divided into two stages: the motile stage and the non-motile stage. All the cells can be classified into forms as follows: motile cell, non-motile cell, zoospore and aplanospore. The main cell proliferation, both in the motile phase and non-motile phase in H. pluvialis, is by asexual reproduction. Under normal growth conditions, a motile cell usually produces two, sometimes four, and exceptionally eight zoospores. Under unfavorable conditions, the motile cell loses its flagella and transforms into a non-motile cell, and the non-motile cell usually produces 2, 4 or 8 aplanospores, and occasionally 20-32 aplanospores, which further develop into non-motile cells. Under suitable conditions, the non-motile cell is also able to release zoospores. The larger non-motile cells produce more than 16 zoospores, and the smaller ones produce 4 or 8 zoospores. Vegetative reproduction is by direct cell division in the motile phase and by occasional cell budding in the non-motile phase. There is, as yet, no convincing direct evidence for sexual reproduction.

  12. 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.

  13. 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.

  14. Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2017-01-01

    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity. PMID:28230069

  15. Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders.

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2017-02-23

    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity.

  16. Heterogeneous differentiation patterns of individual CD8+ T cells.

    Science.gov (United States)

    Gerlach, Carmen; Rohr, Jan C; Perié, Leïla; van Rooij, Nienke; van Heijst, Jeroen W J; Velds, Arno; Urbanus, Jos; Naik, Shalin H; Jacobs, Heinz; Beltman, Joost B; de Boer, Rob J; Schumacher, Ton N M

    2013-05-03

    Upon infection, antigen-specific CD8(+) T lymphocyte responses display a highly reproducible pattern of expansion and contraction that is thought to reflect a uniform behavior of individual cells. We tracked the progeny of individual mouse CD8(+) T cells by in vivo lineage tracing and demonstrated that, even for T cells bearing identical T cell receptors, both clonal expansion and differentiation patterns are heterogeneous. As a consequence, individual naïve T lymphocytes contributed differentially to short- and long-term protection, as revealed by participation of their progeny during primary versus recall infections. The discordance in fate of individual naïve T cells argues against asymmetric division as a singular driver of CD8(+) T cell heterogeneity and demonstrates that reproducibility of CD8(+) T cell responses is achieved through population averaging.

  17. 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.

  18. Detection of the plant parasite Cuscuta reflexa by a tomato cell surface receptor.

    Science.gov (United States)

    Hegenauer, Volker; Fürst, Ursula; Kaiser, Bettina; Smoker, Matthew; Zipfel, Cyril; Felix, Georg; Stahl, Mark; Albert, Markus

    2016-07-29

    Parasitic plants are a constraint on agriculture worldwide. Cuscuta reflexa is a stem holoparasite that infests most dicotyledonous plants. One exception is tomato, which is resistant to C. reflexa We discovered that tomato responds to a small peptide factor occurring in Cuscuta spp. with immune responses typically activated after perception of microbe-associated molecular patterns. We identified the cell surface receptor-like protein CUSCUTA RECEPTOR 1 (CuRe1) as essential for the perception of this parasite-associated molecular pattern. CuRe1 is sufficient to confer responsiveness to the Cuscuta factor and increased resistance to parasitic C. reflexa when heterologously expressed in otherwise susceptible host plants. Our findings reveal that plants recognize parasitic plants in a manner similar to perception of microbial pathogens.

  19. 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

  20. Ultrastructure of autophagy in plant cells: a review.

    Science.gov (United States)

    van Doorn, Wouter G; Papini, Alessio

    2013-12-01

    Just as with yeasts and animal cells, plant cells show several types of autophagy. Microautophagy is the uptake of cellular constituents by the vacuolar membrane. Although microautophagy seems frequent in plants it is not yet fully proven to occur. Macroautophagy occurs farther away from the vacuole. In plants it is performed by autolysosomes, which are considerably different from the autophagosomes found in yeasts and animal cells, as in plants these organelles contain hydrolases from the onset of their formation. Another type of autophagy in plant cells (called mega-autophagy or mega-autolysis) is the massive degradation of the cell at the end of one type of programmed cell death (PCD). Furthermore, evidence has been found for autophagy during degradation of specific proteins, and during the internal degeneration of chloroplasts. This paper gives a brief overview of the present knowledge on the ultrastructure of autophagic processes in plants.

  1. Topology optimization of front metallization patterns for solar cells

    NARCIS (Netherlands)

    Gupta, D.K.; Langelaar, M.; Barink, M.; Keulen, F. van

    2015-01-01

    This paper presents the application of topology optimization (TO) for designing the front electrode patterns for solar cells. Improving the front electrode design is one of the approaches to improve the performance of the solar cells. It serves to produce the voltage distribution for the front surfa

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

    Science.gov (United States)

    Liu, X.; Wang, X.; Zhao, H.; Du, Y.

    2014-11-01

    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.

  3. Analysis of chlorophyll fluorescence reveals stage specific patterns of chloroplast-containing cells during Arabidopsis embryogenesis.

    Science.gov (United States)

    Tejos, Ricardo I; Mercado, Ana V; Meisel, Lee A

    2010-01-01

    The basic body plan of a plant is established early in embryogenesis when cells differentiate, giving rise to the apical and basal regions of the embryo. Using chlorophyll fluorescence as a marker for chloroplasts, we have detected specific patterns of chloroplast-containing cells at specific stages of embryogenesis. Non-randomly distributed chloroplast-containing cells are seen as early as the globular stage of embryogenesis in Arabidopsis. In the heart stage of embryogenesis, chloroplast containing cells are detected in epidermal cells as well as a central region of the heart stage embryo, forming a triangular septum of chloroplast-containing cells that divides the embryo into three equal sectors. Torpedo stage embryos have chloroplast-containing epidermal cells and a central band of chloroplast-containing cells in the cortex layer, just below the shoot apical meristem. In the walking-stick stage of embryogenesis, chloroplasts are present in the epidermal, cortex and endodermal cells. The chloroplasts appear reduced or absent from the provascular and columella cells of walking-stick stage embryos. These results suggest that there is a tight regulation of plastid differentiation during embryogenesis that generates specific patterns of chloroplast-containing cells in specific cell layers at specific stages of embryogenesis.

  4. Isoscapes resolve species-specific spatial patterns in plant-plant interactions in an invaded Mediterranean dune ecosystem.

    Science.gov (United States)

    Hellmann, Christine; Rascher, Katherine G; Oldeland, Jens; Werner, Christiane

    2016-12-01

    Environmental heterogeneity and plant-plant interactions are key factors shaping plant communities. However, the spatial dimension of plant-plant interactions has seldom been addressed in field studies. This is at least partially rooted in a lack of methods that can accurately resolve functional processes in a spatially explicit manner. Isoscapes, that is, spatially explicit representations of stable isotope data, provide a versatile means to trace functional changes on spatial scales, for example, related to N-cycling (foliar δ(15)N) and water use efficiency (WUEi, foliar δ(13)C). In a case study in a nutrient-depleted Mediterranean dune ecosystem, we analysed the spatial impact of the invasive N2-fixing Acacia longifolia on three native species of different functional types using δ(15)N and δ(13)C isoscapes and spatial autocorrelation analyses. Isoscapes revealed strong spatial patterns in δ(15)N and δ(13)C with pronounced species-specific differences, demonstrating distinct spatial ranges of plant-plant interactions. A coniferous tree and an ericaceous dwarf shrub showed significant enrichment in δ(15)N within a range of 5-8 m surrounding the canopy of A. longifolia, indicating input of N originating from symbiotic N2-fixation by the invader. In the dwarf shrub, which was most responsive to invader influence, enrichment in δ(13)C additionally demonstrated spatially explicit changes to WUEi, while a native N2-fixer was unresponsive to the presence of the invader. Furthermore, δ(15)N and δ(13)C isoscapes yielded different patterns, indicating that plant-plant interactions can have distinct spatial distributions and ranges based on the process measured. Additionally, the magnitude of the effect differed between field situations with high and low invasion pressure. This study highlights that the spatial scale must be accounted for when assessing the effects and outcome of species interactions. Functional tracers such as stable isotopes enable us to

  5. Distinct Pattern of Human Vδ1 T Cells Recognizing MICA

    Institute of Scientific and Technical Information of China (English)

    Jianqiang Li; Lianxian Cui; Wei He

    2005-01-01

    γδ T cells represent one unique recognition pattern, the limited recognition, which distinguishes from the specific recognition for αβ T cells and pattern recognition for macrophages. Vδ1 γδ T cell is the major subset of human γδT cells, which predominates in mucosal tissue including the intestinal epithelia. Presently, a few antigens that human Vδ1TCR can recognize have been identified. Among them, MHC class Ⅰ chain-related molecules A (MICA)have been studied most intensively. Besides Vδ1TCR, MICA is also the ligand of NKG2D, a C-type lectin-like activating immunoreceptor. In human, only Vδ1 cells can simultaneously express both types of receptors of MICA while NK cells, αβ T cells and other subsets of γδ T cells likewise express NKG2D. Although the precise mechanisms are still enigmatic, this distinct pattern of Vδ1 cells recognizing MICA predicts unique biological significance of Vδ1 cells in immune defense. Recent years, some progresses have been made in this issue. In this review we summarize the related reports and put forward some novel views based on our group's studies.

  6. The Classification of HEp-2 Cell Patterns Using Fractal Descriptor.

    Science.gov (United States)

    Xu, Rudan; Sun, Yuanyuan; Yang, Zhihao; Song, Bo; Hu, Xiaopeng

    2015-07-01

    Indirect immunofluorescence (IIF) with HEp-2 cells is considered as a powerful, sensitive and comprehensive technique for analyzing antinuclear autoantibodies (ANAs). The automatic classification of the HEp-2 cell images from IIF has played an important role in diagnosis. Fractal dimension can be used on the analysis of image representing and also on the property quantification like texture complexity and spatial occupation. In this study, we apply the fractal theory in the application of HEp-2 cell staining pattern classification, utilizing fractal descriptor firstly in the HEp-2 cell pattern classification with the help of morphological descriptor and pixel difference descriptor. The method is applied to the data set of MIVIA and uses the support vector machine (SVM) classifier. Experimental results show that the fractal descriptor combining with morphological descriptor and pixel difference descriptor makes the precisions of six patterns more stable, all above 50%, achieving 67.17% overall accuracy at best with relatively simple feature vectors.

  7. Plant and animal stem cells: similar yet different.

    Science.gov (United States)

    Heidstra, Renze; Sabatini, Sabrina

    2014-05-01

    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 new tissues. Plant stem cell niches are located within the meristems, which are organized structures that are responsible for most post-embryonic development. The continuous organ production that is characteristic of plant growth requires a robust regulatory network to keep the balance between pluripotent stem cells and differentiating progeny. Components of this network have now been elucidated and provide a unique opportunity for comparing strategies that were developed in the animal and plant kingdoms, which underlie the logic of stem cell behaviour.

  8. 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.

  9. Programmed cell death in the plant immune system.

    Science.gov (United States)

    Coll, N S; Epple, P; Dangl, J L

    2011-08-01

    Cell death has a central role in innate immune responses in both plants and animals. Besides sharing striking convergences and similarities in the overall evolutionary organization of their innate immune systems, both plants and animals can respond to infection and pathogen recognition with programmed cell death. The fact that plant and animal pathogens have evolved strategies to subvert specific cell death modalities emphasizes the essential role of cell death during immune responses. The hypersensitive response (HR) cell death in plants displays morphological features, molecular architectures and mechanisms reminiscent of different inflammatory cell death types in animals (pyroptosis and necroptosis). In this review, we describe the molecular pathways leading to cell death during innate immune responses. Additionally, we present recently discovered caspase and caspase-like networks regulating cell death that have revealed fascinating analogies between cell death control across both kingdoms.

  10. Linking ligand perception by PEPR pattern recognition receptors to cytosolic Ca2+ elevation and downstream immune signaling in plants.

    Science.gov (United States)

    Ma, Yi; Walker, Robin K; Zhao, Yichen; Berkowitz, Gerald A

    2012-11-27

    Little is known about molecular steps linking perception of pathogen invasion by cell surface sentry proteins acting as pattern recognition receptors (PRRs) to downstream cytosolic Ca(2+) elevation, a critical step in plant immune signaling cascades. Some PRRs recognize molecules (such as flagellin) associated with microbial pathogens (pathogen-associated molecular patterns, PAMPs), whereas others bind endogenous plant compounds (damage-associated molecular patterns, DAMPs) such as peptides released from cells upon attack. This work focuses on the Arabidopsis DAMPs plant elicitor peptides (Peps) and their receptors, PEPR1 and PEPR2. Pep application causes in vivo cGMP generation and downstream signaling that is lost when the predicted PEPR receptor guanylyl cyclase (GC) active site is mutated. Pep-induced Ca(2+) elevation is attributable to cGMP activation of a Ca(2+) channel. Some differences were identified between Pep/PEPR signaling and the Ca(2+)-dependent immune signaling initiated by the flagellin peptide flg22 and its cognate receptor Flagellin-sensing 2 (FLS2). FLS2 signaling may have a greater requirement for intracellular Ca(2+) stores and inositol phosphate signaling, whereas Pep/PEPR signaling requires extracellular Ca(2+). Maximal FLS2 signaling requires a functional Pep/PEPR system. This dependence was evidenced as a requirement for functional PEPR receptors for maximal flg22-dependent Ca(2+) elevation, H(2)O(2) generation, defense gene [WRKY33 and Plant Defensin 1.2 (PDF1.2)] expression, and flg22/FLS2-dependent impairment of pathogen growth. In a corresponding fashion, FLS2 loss of function impaired Pep signaling. In addition, a role for PAMP and DAMP perception in bolstering effector-triggered immunity (ETI) is reported; loss of function of either FLS2 or PEPR receptors impaired the hypersensitive response (HR) to an avirulent pathogen.

  11. Insights to PETM Terrestrial Records from Global Patterns in Carbon Isotope Fractionation by Modern Plants

    Science.gov (United States)

    Freeman, K. H.; Diefendorf, A. F.; Mueller, K. E.; Wing, S. L.; Koch, P. L.

    2009-12-01

    Global patterns in plant fractionation and δ13C values of leaves are potentially important for understanding and predicting ecologic impacts of climate change, yet clear, global patterns have not emerged from the copious, highly variable leaf δ13C values published to date. Understanding drivers in modern plant fractionation at large spatial scales has potential to strengthen understanding of isotopic variability in ancient terrestrial organic matter and how it encodes climate and ecological signals. We converted published leaf δ13C-leaf data into mean fractionation values for 334 woody C3 plant species at 105 globally distributed locations to evaluate the influence of environmental properties and plant functional type. Biome designation reflects both community composition and climate properties, so it is not unexpected that in our study it exerts the greatest predictive power on leaf fractionation values. Pulling apart the influences of different environmental factors, precipitation has the next strongest correlation with fractionation, consistent with limitations on photosynthesis and global patterns of ecosystem productivity due to water availability. Individual plant functional types exhibit similar relationships between fractionation and both biome designation and precipitation amount. However, mean fractionation values for evergreen gymnosperms are 1-2.7‰ lower than other woody plant types when environmental factors are constrained. Our results illustrate that both plant type and precipitation can independently result in differences in isotope fractionation of up to several permil. The predictive relationships from our study provide a framework for assessing models of plant fractionation at large spatial scales, and potentially enable predictive spatial mapping of carbon isotopic patterns, both for plants and soil organic carbon. We use these relationships to re-evaluate the 5 ‰ carbon isotope excursion of the PETM in the Bighorn Basin recorded in plant

  12. Plasma-Sprayed Titanium Patterns for Enhancing Early Cell Responses

    Science.gov (United States)

    Shi, Yunqi; Xie, Youtao; Pan, Houhua; Zheng, Xuebin; Huang, Liping; Ji, Fang; Li, Kai

    2016-06-01

    Titanium coating has been widely used as a biocompatible metal in biomedical applications. However, the early cell responses and long-term fixation of titanium implants are not satisfied. To obviate these defects, in this paper, micro-post arrays with various widths (150-1000 μm) and intervals (100-300 μm) were fabricated on the titanium substrate by template-assisted plasma spraying technology. In vitro cell culture experiments showed that MC3T3-E1 cells exhibited significantly higher osteogenic differentiation as well as slightly improved adhesion and proliferation on the micro-patterned coatings compared with the traditional one. The cell number on the pattern with 1000 µm width reached 130% after 6 days of incubation, and the expressions of osteopontin (OPN) as well as osteocalcin (OC) were doubled. No obvious difference was found in cell adhesion on various size patterns. The present micro-patterned coatings proposed a new modification method for the traditional plasma spraying technology to enhance the early cell responses and convenience for the bone in-growth.

  13. 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...... a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. In this consortium, P. putida is reliant on microcolonies formed by Acinetobacter sp. C6 — to which it attaches. Here we describe the processes that lead to the microcolony......-pattern by Acinetobacter sp. C6. Ecological spatial pattern analyses revealed that the microcolonies were not entirely randomly distributed, and instead arranged in a uniform pattern. Detailed time-lapse confocal microscopy at the single cell level demonstrated that the spatial pattern was the result of an intriguing self...

  14. 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)

  15. Epigenetic memory and cell fate reprogramming in plants.

    Science.gov (United States)

    Birnbaum, Kenneth D; Roudier, François

    2017-02-01

    Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration.

  16. Formative cell divisions: principal determinants of plant morphogenesis.

    Science.gov (United States)

    Smolarkiewicz, Michalina; Dhonukshe, Pankaj

    2013-03-01

    Formative cell divisions utilizing precise rotations of cell division planes generate and spatially place asymmetric daughters to produce different cell layers. Therefore, by shaping tissues and organs, formative cell divisions dictate multicellular morphogenesis. In animal formative cell divisions, the orientation of the mitotic spindle and cell division planes relies on intrinsic and extrinsic cortical polarity cues. Plants lack known key players from animals, and cell division planes are determined prior to the mitotic spindle stage. Therefore, it appears that plants have evolved specialized mechanisms to execute formative cell divisions. Despite their profound influence on plant architecture, molecular players and cellular mechanisms regulating formative divisions in plants are not well understood. This is because formative cell divisions in plants have been difficult to track owing to their submerged positions and imprecise timings of occurrence. However, by identifying a spatiotemporally inducible cell division plane switch system applicable for advanced microscopy techniques, recent studies have begun to uncover molecular modules and mechanisms for formative cell divisions. The identified molecular modules comprise developmentally triggered transcriptional cascades feeding onto microtubule regulators that now allow dissection of the hierarchy of the events at better spatiotemporal resolutions. Here, we survey the current advances in understanding of formative cell divisions in plants in the context of embryogenesis, stem cell functionality and post-embryonic organ formation.

  17. 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.

  18. Cell Fate Switch during In Vitro Plant Organogenesis

    Institute of Scientific and Technical Information of China (English)

    Xiang Yu Zhao; Ying Hua Su; Zhi Juan Cheng; Xian Sheng Zhang

    2008-01-01

    Plant mature cells have the capability to reverse their state of differenUation and produce new organs under cultured conditions. Two phases, dedifferentiation and redifferentiation, are commonly characterized during in vitro organogenesis.In these processes, cells undergo fate switch several times regulated by both extrinsic and intrinsic factors, which are associated with reentry to the cell cycle, the balance between euchromatin and heterochromatin, reprogramming of gene expression, and so forth. This short article reviews the advances in the mechanism of organ regeneration from plant somatic cells in molecular, genomic and epigenetic aspects, aiming to provide important information on the mechanism underlying cell fate switch during in vitro plant organogenesis.

  19. Plant cell wall-degrading enzymes and their secretion in plant-pathogenic fungi.

    Science.gov (United States)

    Kubicek, Christian P; Starr, Trevor L; Glass, N Louise

    2014-01-01

    Approximately a tenth of all described fungal species can cause diseases in plants. A common feature of this process is the necessity to pass through the plant cell wall, an important barrier against pathogen attack. To this end, fungi possess a diverse array of secreted enzymes to depolymerize the main structural polysaccharide components of the plant cell wall, i.e., cellulose, hemicellulose, and pectin. Recent advances in genomic and systems-level studies have begun to unravel this diversity and have pinpointed cell wall-degrading enzyme (CWDE) families that are specifically present or enhanced in plant-pathogenic fungi. In this review, we discuss differences between the CWDE arsenal of plant-pathogenic and non-plant-pathogenic fungi, highlight the importance of individual enzyme families for pathogenesis, illustrate the secretory pathway that transports CWDEs out of the fungal cell, and report the transcriptional regulation of expression of CWDE genes in both saprophytic and phytopathogenic fungi.

  20. 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.

  1. 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.

  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. 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.

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

    DEFF Research Database (Denmark)

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

    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...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...

  6. Chemical- and pathogen-induced programmed cell death in plants

    NARCIS (Netherlands)

    Iakimova, E.T.; Atanassov, A.; Woltering, E.J.

    2005-01-01

    This review focuses on recent update in the understanding of programmed cell death regarding the differences and similarities between the diverse types of cell death in animal and plant systems and describes the morphological and some biochemical determinants. The role of PCD in plant development an

  7. Generation of Viable Cell and Biomaterial Patterns by Laser Transfer

    Science.gov (United States)

    Ringeisen, Bradley

    2001-03-01

    In order to fabricate and interface biological systems for next generation applications such as biosensors, protein recognition microarrays, and engineered tissues, it is imperative to have a method of accurately and rapidly depositing different active biomaterials in patterns or layered structures. Ideally, the biomaterial structures would also be compatible with many different substrates including technologically relevant platforms such as electronic circuits or various detection devices. We have developed a novel laser-based technique, termed matrix assisted pulsed laser evaporation direct write (MAPLE DW), that is able to direct write patterns and three-dimensional structures of numerous biologically active species ranging from proteins and antibodies to living cells. Specifically, we have shown that MAPLE DW is capable of forming mesoscopic patterns of living prokaryotic cells (E. coli bacteria), living mammalian cells (Chinese hamster ovaries), active proteins (biotinylated bovine serum albumin, horse radish peroxidase), and antibodies specific to a variety of classes of cancer related proteins including intracellular and extracellular matrix proteins, signaling proteins, cell cycle proteins, growth factors, and growth factor receptors. In addition, patterns of viable cells and active biomolecules were deposited on different substrates including metals, semiconductors, nutrient agar, and functionalized glass slides. We will present an explanation of the laser-based transfer mechanism as well as results from our recent efforts to fabricate protein recognition microarrays and tissue-based microfluidic networks.

  8. Multiscale patterned transplantable stem cell patches for bone tissue regeneration.

    Science.gov (United States)

    Kim, Jangho; Bae, Won-Gyu; Choung, Han-Wool; Lim, Ki Taek; Seonwoo, Hoon; Jeong, Hoon Eui; Suh, Khap-Yang; Jeon, Noo Li; Choung, Pill-Hoon; Chung, Jong Hoon

    2014-11-01

    Stem cell-based therapy has been proposed as an enabling alternative not only for the treatment of diseases but also for the regeneration of tissues beyond complex surgical treatments or tissue transplantation. In this study, we approached a conceptual platform that can integrate stem cells into a multiscale patterned substrate for bone regeneration. Inspired by human bone tissue, we developed hierarchically micro- and nanopatterned transplantable patches as synthetic extracellular matrices by employing capillary force lithography in combination with a surface micro-wrinkling method using a poly(lactic-co-glycolic acid) (PLGA) polymer. The multiscale patterned PLGA patches were highly flexible and showed higher tissue adhesion to the underlying tissue than did the single nanopatterned patches. In response to the anisotropically multiscale patterned topography, the adhesion and differentiation of human mesenchymal stem cells (hMSCs) were sensitively controlled. Furthermore, the stem cell patch composed of hMSCs and transplantable PLGA substrate promoted bone regeneration in vivo when both the micro- and nanotopography of the substrate surfaces were synergistically combined. Thus, our study concludes that multiscale patterned transplantable stem cell patches may have a great potential for bone regeneration as well as for various regenerative medicine approaches.

  9. Immunohistochemical patterns of follicular dendritic cell meshwork and Ki-67 in small B-cell lymphomas

    Institute of Scientific and Technical Information of China (English)

    时云飞

    2013-01-01

    Objective To identify the immunohistochemical patterns of follicular dendritic cell(FDC)meshwork and Ki-67labeling index in small B-cell lymphomas(SBLs) and their significance in differential diagnosis.Methods

  10. Cell cycling and patterned cell proliferation in the wing primordium of Drosophila.

    OpenAIRE

    1996-01-01

    The pattern of cell proliferation in the Drosophila imaginal wing primordium is spatially and temporally heterogeneous. Direct visualization of cells in S, G2, and mitosis phases of the cell cycle reveals several features invariant throughout development. The fraction of cells in the disc in the different cell cycle stages is constant, the majority remaining in G1. Cells in the different phases of the cell cycle mainly appear in small synchronic clusters that are nonclonally derived but resul...

  11. 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.

  12. Patterns of synonymous codon usage bias in chloroplast genomes of seed plants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Codon usage in chloroplast genome of six seed plants (Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum,Pinus koraiensis and Cycas taitungensis) was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants.The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons (ENC) for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon us-age. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.

  13. The role of root border cells in plant defense.

    Science.gov (United States)

    Hawes, M C; Gunawardena, U; Miyasaka, S; Zhao, X

    2000-03-01

    The survival of a plant depends upon the capacity of root tips to sense and move towards water and other nutrients in the soil. Perhaps because of the root tip's vital role in plant health, it is ensheathed by large populations of detached somatic cells - root 'border' cells - which have the ability to engineer the chemical and physical properties of the external environment. Of particular significance, is the production by border cells of specific chemicals that can dramatically alter the behavior of populations of soilborne microflora. Molecular approaches are being used to identify and manipulate the expression of plant genes that control the production and the specialized properties of border cells in transgenic plants. Such plants can be used to test the hypothesis that these unusual cells act as a phalanx of biological 'goalies', which neutralize dangers to newly generated root tissue as the root tip makes its way through soil.

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

    Directory of Open Access Journals (Sweden)

    Lucia de la Torre

    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. Animal and plant stem cells concepts, propagation and engineering

    CERN Document Server

    Pavlović, Mirjana

    2017-01-01

    This book provides a multifaceted look into the world of stem cells and explains the similarities and differences between plant and human stem cells. It explores the intersection between animals and plants and explains their cooperative role in bioengineering studies. The book treats both theoretical and practical aspects of stem cell research. It covers the advantages and limitations of many common applications related to stem cells: their sources, categories, engineering of these cells, reprogramming of their functions, and their role as novel cellular therapeutic approach. Written by experts in the field, the book focuses on aspects of stem cells ranging from expansion-propagation to metabolic reprogramming. It introduces the emergence of cancer stem cells and different modalities in targeted cancer stem cell therapies. It is a valuable source of fresh information for academics and researchers, examining molecular mechanisms of animal and plant stem cell regulation and their usage for therapeutic applicati...

  16. Discovering urban activity patterns in cell phone data

    OpenAIRE

    Widhalm, Peter; Yang, Yingxiang; Ulm, Michael; Athavale, Shounak; Gonzalez, Marta C.

    2015-01-01

    Massive and passive data such as cell phone traces provide samples of the whereabouts and movements of individuals. These are a potential source of information for models of daily activities in a city. The main challenge is that phone traces have low spatial precision and are sparsely sampled in time, which requires a precise set of techniques for mining hidden valuable information they contain. Here we propose a method to reveal activity patterns that emerge from cell phone data by analyzing...

  17. 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

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Cécile eALBENNE

    2013-05-01

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

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

    Science.gov (United States)

    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 walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions.

  1. Spatial patterns of plant litter in a tidal freshwater marsh and implications for marsh persistence.

    Science.gov (United States)

    Elmore, Andrew J; Engelhardt, Katharina A M; Cadol, Daniel; Palinkas, Cindy M

    2016-04-01

    The maintenance of marsh platform elevation under conditions of sea level rise is dependent on mineral sediment supply to marsh surfaces and conversion of above- and belowground plant biomass 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 a variable related to aboveground biomass, plant litter, to reveal its role in the maintenance of marsh surfaces. Plant litter persisting through the dormant season represents the more recalcitrant portion of plant biomass, and as such has an extended period of influence on ecosystem processes. We conducted a field and remote sensing analysis of plant litter height, aboveground biomass, vertical cover, and stem density (collectively termed plant litter structure) at a tidal freshwater marsh located within the Potomac River estuary, USA. LiDAR and field observations show that plant litter structure becomes more prominent with increasing elevation. Spatial patterns in litter structure exhibit stability from year to year and correlate with patterns in soil organic matter content, revealed by measuring the loss on ignition of surface sediments. The amount of mineral material embedded within plant litter decreases with increasing elevation, representing an important tradeoff 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, aboveground litter contributes organic matter to soil development. This organic matter contribution has the potential to eclipse that of belowground biomass as the root:shoot ratio of dominant species at high elevations is low compared to that of dominant species at low elevations. Because of these tradeoffs in mineral and organic matter incorporation into soil across elevation gradients, the rate of

  2. Expressional patterns of chaperones in ten human tumor cell lines

    Directory of Open Access Journals (Sweden)

    Slavc Irene

    2004-12-01

    Full Text Available Abstract Background Chaperones (CH play an important role in tumor biology but no systematic work on expressional patterns has been reported so far. The aim of the study was therefore to present an analytical method for the concomitant determination of several CH in human tumor cell lines, to generate expressional patterns in the individual cell lines and to search for tumor and non-tumor cell line specific CH expression. Human tumor cell lines of neuroblastoma, colorectal and adenocarcinoma of the ovary, osteosarcoma, rhabdomyosarcoma, malignant melanoma, lung, cervical and breast cancer, promyelocytic leukaemia were homogenised, proteins were separated on two-dimensional gel electrophoresis with in-gel digestion of proteins and MALDI-TOF/TOF analysis was carried out for the identification of CH. Results A series of CH was identified including the main CH groups as HSP90/HATPas_C, HSP70, Cpn60_TCP1, DnaJ, Thioredoxin, TPR, Pro_isomerase, HSP20, ERP29_C, KE2, Prefoldin, DUF704, BAG, GrpE and DcpS. Conclusions The ten individual tumor cell lines showed different expression patterns, which are important for the design of CH studies in tumor cell lines. The results can serve as a reference map and form the basis of a concomitant determination of CH by a protein chemical rather than an immunochemical method, independent of antibody availability or specificity.

  3. Development of Spatial Distribution Patterns by Biofilm Cells.

    Science.gov (United States)

    Haagensen, Janus A J; Hansen, Susse K; Christensen, Bjarke B; Pamp, Sünje J; Molin, Søren

    2015-09-01

    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. strain C6, originally isolated from a creosote-polluted aquifer, has evolved a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. In this consortium, P. putida is reliant on microcolonies formed by Acinetobacter sp. C6, to which it attaches. Here we describe the processes that lead to the microcolony pattern by Acinetobacter sp. C6. Ecological spatial pattern analyses revealed that the microcolonies were not entirely randomly distributed and instead were arranged in a uniform pattern. Detailed time-lapse confocal microscopy at the single-cell level demonstrated that the spatial pattern was the result of an intriguing self-organization: small multicellular clusters moved along the surface to fuse with one another to form microcolonies. This active distribution capability was dependent on environmental factors (carbon source and oxygen) and historical contingency (formation of phenotypic variants). The findings of this study are discussed in the context of species distribution patterns observed in macroecology, and we summarize observations about the processes involved in coadaptation between P. putida and Acinetobacter sp. C6. Our results contribute to an understanding of spatial species distribution patterns as they are observed in nature, as well as the ecology of engineered communities that have the potential for enhanced and sustainable bioprocessing capacity.

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Gabriel Paës

    2014-07-01

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

  6. Multidimensional solid-state NMR spectroscopy of plant cell walls.

    Science.gov (United States)

    Wang, Tuo; Phyo, Pyae; Hong, Mei

    2016-09-01

    Plant biomass has become an important source of bio-renewable energy in modern society. The molecular structure of plant cell walls is difficult to characterize by most atomic-resolution techniques due to the insoluble and disordered nature of the cell wall. Solid-state NMR (SSNMR) spectroscopy is uniquely suited for studying native hydrated plant cell walls at the molecular level with chemical resolution. Significant progress has been made in the last five years to elucidate the molecular structures and interactions of cellulose and matrix polysaccharides in plant cell walls. These studies have focused on primary cell walls of growing plants in both the dicotyledonous and grass families, as represented by the model plants Arabidopsis thaliana, Brachypodium distachyon, and Zea mays. To date, these SSNMR results have shown that 1) cellulose, hemicellulose, and pectins form a single network in the primary cell wall; 2) in dicot cell walls, the protein expansin targets the hemicellulose-enriched region of the cellulose microfibril for its wall-loosening function; and 3) primary wall cellulose has polymorphic structures that are distinct from the microbial cellulose structures. This article summarizes these key findings, and points out future directions of investigation to advance our fundamental understanding of plant cell wall structure and function.

  7. Fuel Cell Power Plants Renewable and Waste Fuels

    Science.gov (United States)

    2011-01-13

    Fuel Cell Power Plants Renewable and Waste Fuels DOE-DOD Workshop Washington, DC. January 13, 2011 reliable, efficient, ultra-clean Report...2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Fuel Cell Power Plants Renewable and Waste Fuels 5a. CONTRACT...Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES presented at the DOE-DOD Waste-to-Energy using Fuel Cells Workshop held

  8. 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.

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

    Science.gov (United States)

    Verma, R. S.; Dasgupta, R.; Ahlawat, S.; Kumar, N.; Uppal, A.; Gupta, P. K.

    2013-08-01

    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.

  10. 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. 

  11. High resolution imaging of surface patterns of single bacterial cells

    Energy Technology Data Exchange (ETDEWEB)

    Greif, Dominik; Wesner, Daniel [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany); Regtmeier, Jan, E-mail: jan.regtmeier@physik.uni-bielefeld.de [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany); Anselmetti, Dario [Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld (Germany)

    2010-09-15

    We systematically studied the origin of surface patterns observed on single Sinorhizobium meliloti bacterial cells by comparing the complementary techniques atomic force microscopy (AFM) and scanning electron microscopy (SEM). Conditions ranged from living bacteria in liquid to fixed bacteria in high vacuum. Stepwise, we applied different sample modifications (fixation, drying, metal coating, etc.) and characterized the observed surface patterns. A detailed analysis revealed that the surface structure with wrinkled protrusions in SEM images were not generated de novo but most likely evolved from similar and naturally present structures on the surface of living bacteria. The influence of osmotic stress to the surface structure of living cells was evaluated and also the contribution of exopolysaccharide and lipopolysaccharide (LPS) by imaging two mutant strains of the bacterium under native conditions. AFM images of living bacteria in culture medium exhibited surface structures of the size of single proteins emphasizing the usefulness of AFM for high resolution cell imaging.

  12. 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.

  13. Patterning cells on optically transparent indium tin oxide electrodes.

    Science.gov (United States)

    Shah, Sunny; Revzin, Alexander

    2007-01-01

    The ability to exercise precise spatial and temporal control over cell-surface interactions is an important prerequisite to the assembly of multi-cellular constructs serving as in vitro mimics of native tissues. In this study, photolithography and wet etching techniques were used to fabricate individually addressable indium tin oxide (ITO) electrodes on glass substrates. The glass substrates containing ITO microelectrodes were modified with poly(ethylene glycol) (PEG) silane to make them protein and cell resistive. Presence of insulating PEG molecules on the electrode surface was verified by cyclic voltammetry employing potassium ferricyanide as a redox reporter molecule. Importantly, the application of reductive potential caused desorption of the PEG layer, resulting in regeneration of the conductive electrode surface and appearance of typical ferricyanide redox peaks. Application of reductive potential also corresponded to switching of ITO electrode properties from cell non-adhesive to cell-adhesive. Electrochemical stripping of PEG-silane layer from ITO microelectrodes allowed for cell adhesion to take place in a spatially defined fashion, with cellular patterns corresponding closely to electrode patterns. Micropatterning of several cell types was demonstrated on these substrates. In the future, the control of the biointerfacial properties afforded by this method will allow to engineer cellular microenvironments through the assembly of three or more cell types into a precise geometric configuration on an optically transparent substrate.

  14. Small molecule probes for plant cell wall polysaccharide imaging

    Directory of Open Access Journals (Sweden)

    Ian eWallace

    2012-05-01

    Full Text Available Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics.

  15. Parasitic worms stimulate host NADPH oxidases to produce reactive oxygen species that limit plant cell death and promote infection.

    Science.gov (United States)

    Siddique, Shahid; Matera, Christiane; Radakovic, Zoran S; Hasan, M Shamim; Gutbrod, Philipp; Rozanska, Elzbieta; Sobczak, Miroslaw; Torres, Miguel Angel; Grundler, Florian M W

    2014-04-08

    Plants and animals produce reactive oxygen species (ROS) in response to infection. In plants, ROS not only activate defense responses and promote cell death to limit the spread of pathogens but also restrict the amount of cell death in response to pathogen recognition. Plants also use hormones, such as salicylic acid, to mediate immune responses to infection. However, there are long-lasting biotrophic plant-pathogen interactions, such as the interaction between parasitic nematodes and plant roots during which defense responses are suppressed and root cells are reorganized to specific nurse cell systems. In plants, ROS are primarily generated by plasma membrane-localized NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidases, and loss of NADPH oxidase activity compromises immune responses and cell death. We found that infection of Arabidopsis thaliana by the parasitic nematode Heterodera schachtii activated the NADPH oxidases RbohD and RbohF to produce ROS, which was necessary to restrict infected plant cell death and promote nurse cell formation. RbohD- and RbohF-deficient plants exhibited larger regions of cell death in response to nematode infection, and nurse cell formation was greatly reduced. Genetic disruption of SID2, which is required for salicylic acid accumulation and immune activation in nematode-infected plants, led to the increased size of nematodes in RbohD- and RbohF-deficient plants, but did not decrease plant cell death. Thus, by stimulating NADPH oxidase-generated ROS, parasitic nematodes fine-tune the pattern of plant cell death during the destructive root invasion and may antagonize salicylic acid-induced defense responses during biotrophic life stages.

  16. 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.

  17. Guard cell protoplasts: isolation, culture, and regeneration of plants.

    Science.gov (United States)

    Tallman, Gary

    2006-01-01

    Guard cell protoplasts have been used extensively in short-term experiments designed to elucidate the signal transduction mechanisms that regulate stomatal movements. The utility of uard cell protoplasts for other types of longer-term signal transduction experiments is just now being realized. Because highly purified, primary isolates of guard cell protoplasts are synchronous initially, they are uniform in their responses to changes in culture conditions. Such isolates have demonstrated potential to reveal mechanisms that underlie hormonal signalling for plant cell survival, cell cycle re-entry, reprogramming of genes during dedifferentiation to an embryogenic state, and plant cell thermotolerance. Plants have been regenerated from cultured guard cell protoplasts of two species: Nicotiana glauca (Graham), tree tobacco, and Beta vulgaris, sugar beet. Plants genetically engineered for herbicide tolerance have been regenerated from cultured guard cell protoplasts of B. vulgaris. The method for isolating, culturing, and regenerating plants from guard cell protoplasts of N. glauca is described here. A recently developed procedure for large-scale isolation of these cells from as many as nine leaves per experiment is described. Using this protocol, yields of 1.5-2 x 10(7) per isolate may be obtained. Such yields are sufficient for standard methods of molecular, biochemical, and proteomic analysis.

  18. 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

  19. 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.

  20. 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.

  1. VirtualLeaf: an open source framework for cell-based modeling of plant tissue growth and development

    NARCIS (Netherlands)

    Merks, R.M.H.; Guravage, M.A.; Inze, D.; Beemster, G.T.S.

    2011-01-01

    Plant organs, including leaves and roots, develop by means of a multi-level crosstalk between gene regulation, patterned cell division and cell expansion, and tissue mechanics. The multi-level regulatory mechanisms complicate classic molecular genetics or functional genomics approaches to biological

  2. 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.

    2016-08-01

    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.

  3. Voronoi Cell Patterns: theoretical model and application to submonolayer growth

    Science.gov (United States)

    González, Diego Luis; Einstein, T. L.

    2012-02-01

    We use a simple fragmentation model to describe the statistical behavior of the Voronoi cell patterns generated by a homogeneous and isotropic set of points in 1D and in 2D. In particular, we are interested in the distribution of sizes of these Voronoi cells. Our model is completely defined by two probability distributions in 1D and again in 2D, the probability to add a new point inside an existing cell and the probability that this new point is at a particular position relative to the preexisting point inside this cell. In 1D the first distribution depends on a single parameter while the second distribution is defined through a fragmentation kernel; in 2D both distributions depend on a single parameter. The fragmentation kernel and the control parameters are closely related to the physical properties of the specific system under study. We apply our model to describe the Voronoi cell patterns of island nucleation for critical island sizes i=0,1,2,3. Experimental results for the Voronoi cells of InAs/GaAs quantum dots are also described by our model.

  4. Conservation and divergence of plant LHP1 protein sequences and expression patterns in angiosperms and gymnosperms.

    Science.gov (United States)

    Guan, Hexin; Zheng, Zhengui; Grey, Paris H; Li, Yuhua; Oppenheimer, David G

    2011-05-01

    Floral transition is a critical and strictly regulated developmental process in plants. Mutations in Arabidopsis LIKE HETEROCHROMATIN PROTEIN 1 (AtLHP1)/TERMINAL FLOWER 2 (TFL2) result in early and terminal flowers. Little is known about the gene expression, function and evolution of plant LHP1 homologs, except for Arabidopsis LHP1. In this study, the conservation and divergence of plant LHP1 protein sequences was analyzed by sequence alignments and phylogeny. LHP1 expression patterns were compared among taxa that occupy pivotal phylogenetic positions. Several relatively conserved new motifs/regions were identified among LHP1 homologs. Phylogeny of plant LHP1 proteins agreed with established angiosperm relationships. In situ hybridization unveiled conserved expression of plant LHP1 in the axillary bud/tiller, vascular bundles, developing stamens, and carpels. Unlike AtLHP1, cucumber CsLHP1-2, sugarcane SoLHP1 and maize ZmLHP1, rice OsLHP1 is not expressed in the shoot apical meristem (SAM) and the OsLHP1 transcript level is consistently low in shoots. "Unequal crossover" might have contributed to the divergence in the N-terminal and hinge region lengths of LHP1 homologs. We propose an "insertion-deletion" model for soybean (Glycine max L.) GmLHP1s evolution. Plant LHP1 homologs are more conserved than previously expected, and may favor vegetative meristem identity and primordia formation. OsLHP1 may not function in rice SAM during floral induction.

  5. Changes in dominance patterns in upper Carboniferous plant-fossil assemblages

    Science.gov (United States)

    Pfefferkorn, Hermann W.; Thomson, Margaret C.

    1982-12-01

    Upper Carboniferous (Pennsylvanian) terrestrial clastic rocks from North America and Europe contain compression-impression plant-fossil assemblages that represent the remains of plant communities that grew on floodplains, levees, and other clastic facies of fluvial and deltaic lowlands. Quantitative analysis of 66 plant-fossil assemblages spanning the entire late Carboniferous demonstrates that before the middle of the Westphalian D Stage the majority of plant-fossil assemblages are dominated by pteridosperms and sphenopsids. Lycopods and cordaites dominate only a few assemblages counted. Ferns do not dominate any assemblages. These findings contrast sharply with the dominance of lycopods reported by others from coal swamps of the same time interval. Above the middle of the Westphalian D, however, one-third of the compression-impression assemblages counted are dominated by ferns. The change in dominance pattern in compression-impression plant-fossil assemblages occurs half a stage earlier than the previously reported change from lycopod-dominated to fern-dominated assemblages at the Westphalian-Stephanian boundary in coal swamps. A trend toward dryer climate during Westphalian D apparently influenced plants growing on better-drained alluvial soils earlier than those growing on water-logged soils of contemporaneous coal swamps. *Present address: Room 108 Math.-Geology Building, University of Minnesota, Duluth, Minnesota 55812

  6. An epigenetic view of plant cells cultured in vitro: somaclonal variation and beyond.

    Science.gov (United States)

    Miguel, Célia; Marum, Liliana

    2011-07-01

    Epigenetic mechanisms are highly dynamic events that modulate gene expression. As more accurate and powerful tools for epigenetic analysis become available for application in a broader range of plant species, analysis of the epigenetic landscape of plant cell cultures may turn out to be crucial for understanding variant phenotypes. In vitro plant cell and tissue culture methodologies are important for many ongoing plant propagation and breeding programmes as well as for cutting-edge research in several plant model species. Although it has long been known that in vitro conditions induce variation at several levels, most studies using such conditions rely on the assumption that in vitro cultured plant cells/tissues mostly conform genotypically and phenotypically. However, when large-scale clonal propagation is the aim, there has been a concern in confirming true-to-typeness using molecular markers for evaluating stability. While in most reports genetic variation has been found to occur at relatively modest frequencies, variation in DNA methylation patterns seems to be much more frequent and in some cases it has been directly implicated in phenotypic variation. Recent advances in the field of epigenetics have uncovered highly dynamic mechanisms of chromatin remodelling occurring during cell dedifferentiation and differentiation processes on which in vitro adventitious plant regeneration systems are based. Here, an overview of recent findings related to developmental switches occurring during in vitro culture is presented. Additionally, an update on the detection of epigenetic variation in plant cell cultures will be provided and discussed in the light of recent progress in the plant epigenetics field.

  7. Glycoproteins from sugarcane plants regulate cell polarity of Ustilago scitaminea teliospores.

    Science.gov (United States)

    Millanes, Ana-María; Fontaniella, Blanca; Legaz, María-Estrella; Vicente, Carlos

    2005-03-01

    Saccharum officinarum, cv. Mayarí, is a variety of sugarcane resistant to smut disease caused by Ustilago scitaminea. Sugarcane naturally produces glycoproteins that accumulate in the parenchymatous cells of stalks. These glycoproteins contain a heterofructan as polysaccharide moiety. The concentration of these glycoproteins clearly increases after inoculation of sugarcane plants with smut teliospores, although major symptoms of disease are not observed. These glycoproteins induce homotypic adhesion and inhibit teliospore germination. When glycoproteins from healthy, non-inoculated plants are fractionated, they inhibit actin capping, which occurs before teliospore germination. However, inoculation of smut teliospores induce glycoprotein fractions that promote teliospore polarity and are different from those obtained from healthy plants. These fractions exhibit arginase activity, which is strongly enhanced in inoculated plants. Arginase from healthy plants binds to cell wall teliospores and it is completely desorpted by sucrose, but only 50% of arginase activity from inoculated plants is desorpted by the disaccharide. The data presented herein are consistent with a model of excess arginase entry into teliospores. Arginase synthesized by sugarcane plants as a response to the experimental infection would increase the synthesis of putrescine, which impedes polarization at concentration values higher than 0.05 mM. However, smut teliospores seem to be able to change the pattern of glycoprotein production by sugarcane, thereby promoting the synthesis of different glycoproteins that activate polarization after binding to their cell wall ligand.

  8. Formation and maintenance of the Golgi apparatus in plant cells.

    Science.gov (United States)

    Ito, Yoko; Uemura, Tomohiro; Nakano, Akihiko

    2014-01-01

    The Golgi apparatus plays essential roles in intracellular trafficking, protein and lipid modification, and polysaccharide synthesis in eukaryotic cells. It is well known for its unique stacked structure, which is conserved among most eukaryotes. However, the mechanisms of biogenesis and maintenance of the structure, which are deeply related to ER-Golgi and intra-Golgi transport systems, have long been mysterious. Now having extremely powerful microscopic technologies developed for live-cell imaging, the plant Golgi apparatus provides an ideal system to resolve the question. The plant Golgi apparatus has unique features that are not conserved in other kingdoms, which will also give new insights into the Golgi functions in plant life. In this review, we will summarize the features of the plant Golgi apparatus and transport mechanisms around it, with a focus on recent advances in Golgi biogenesis by live imaging of plants cells.

  9. Hosting the plant cells in vitro: recent trends in bioreactors.

    Science.gov (United States)

    Georgiev, Milen I; Eibl, Regine; Zhong, Jian-Jiang

    2013-05-01

    Biotechnological production of high-value metabolites and therapeutic proteins by plant in vitro systems has been considered as an attractive alternative of classical technologies. Numerous proof-of-concept studies have illustrated the feasibility of scaling up plant in vitro system-based processes while keeping their biosynthetic potential. Moreover, several commercial processes have been established so far. Though the progress on the field is still limited, in the recent years several bioreactor configurations has been developed (e.g., so-called single-use bioreactors) and successfully adapted for growing plant cells in vitro. This review highlights recent progress and limitations in the bioreactors for plant cells and outlines future perspectives for wider industrialization of plant in vitro systems as "green cell factories" for sustainable production of value-added molecules.

  10. Ectomycorrhizal impacts on plant nitrogen nutrition: emerging isotopic patterns, latitudinal variation and hidden mechanisms.

    Science.gov (United States)

    Mayor, Jordan; Bahram, Mohammad; Henkel, Terry; Buegger, Franz; Pritsch, Karin; Tedersoo, Leho

    2015-01-01

    Ectomycorrhizal (EcM)-mediated nitrogen (N) acquisition is one main strategy used by terrestrial plants to facilitate growth. Measurements of natural abundance nitrogen isotope ratios (denoted as δ(15)N relative to a standard) increasingly serve as integrative proxies for mycorrhiza-mediated N acquisition due to biological fractionation processes that alter (15)N:(14)N ratios. Current understanding of these processes is based on studies from high-latitude ecosystems where plant productivity is largely limited by N availability. Much less is known about the cause and utility of ecosystem δ(15)N patterns in the tropics. Using structural equation models, model selection and isotope mass balance we assessed relationships among co-occurring soil, mycorrhizal plants and fungal N pools measured from 40 high- and 9 low-latitude ecosystems. At low latitudes (15)N-enrichment caused ecosystem components to significantly deviate from those in higher latitudes. Collectively, δ(15)N patterns suggested reduced N-dependency and unique sources of EcM (15)N-enrichment under conditions of high N availability typical of the tropics. Understanding the role of mycorrhizae in global N cycles will require reevaluation of high-latitude perspectives on fractionation sources that structure ecosystem δ(15)N patterns, as well as better integration of EcM function with biogeochemical theories pertaining to climate-nutrient cycling relationships.

  11. Susceptibility pattern of Malassezia species to selected plant extracts and antifungal agents

    Directory of Open Access Journals (Sweden)

    G Sibi

    2014-01-01

    Full Text Available Objective: Malassezia is associated with dandruff, seborrhoeic dermatitis, pityriasis versicolor folliculitis and atopic eczema. This study determined the susceptibility pattern of Malassezia furfur, M. globosa, M. obtusa, M. restricta, M. slooffiae and M. sympodialis isolated from patients diagnosed with dandruff against plant extracts and antifungal agents. Materials and Methods: Twenty aqueous plant extracts and five azole drugs were tested against the isolates by well diffusion and broth dilution method. Results: Among the plant extracts, Phyllanthus emblica (fruits, Hibiscus rosa sinensis (flowers and Acacia concinna (pods have demonstrated significant antidandruff activity. Minimum inhibitory concentration values revealed that ketoconazole as the most effective drug followed by itraconazole. Conclusion: M. furfur and M. globosa were found as the most susceptible organisms against the aqueous extracts of Phyllanthus emblica (fruits, Hibiscus rosa sinensis (flowers, Acacia concinna (pods and azole drugs.

  12. Interactions in the patterns of vegetative growth and reproduction in woody dioecious plants.

    Science.gov (United States)

    Hoffmann, A J; Alliende, M C

    1984-01-01

    Interactions between vegetative growth and reproduction were evaluated in Peumus boldus, Lithraea caustica and Laretia acaulis, three woody dioecious species in central Chile. Phenological observations were made periodically on marked branches of male and female plants, and biomass allocation (dry weight) to vegetative and reproductive tissues was measured. The magnitude of flowering was evaluated in groups of plants in three successive seasons. The patterns of activities are species- and sex-dependent, and cycles of 2-4 years have been established. Branches that produce flowers either do not grow or grow less than branches without flowers, and males and females have differential resource allocation: male branches attain higher biomass values. Groups of plants show seasonal behavior that suggest synchrony in their reproductive activities.

  13. Cytokinesis in plant and animal cells: endosomes 'shut the door'.

    Science.gov (United States)

    Baluska, Frantisek; Menzel, Diedrik; Barlow, Peter W

    2006-06-01

    For many years, cytokinesis in eukaryotic cells was considered to be a process that took a variety of forms. This is rather surprising in the face of an apparently conservative mitosis. Animal cytokinesis was described as a process based on an actomyosin-based contractile ring, assembling, and acting at the cell periphery. In contrast, cytokinesis of plant cells was viewed as the centrifugal generation of a new cell wall by fusion of Golgi apparatus-derived vesicles. However, recent advances in animal and plant cell biology have revealed that many features formerly considered as plant-specific are, in fact, valid also for cytokinetic animal cells. For example, vesicular trafficking has turned out to be important not only for plant but also for animal cytokinesis. Moreover, the terminal phase of animal cytokinesis based on midbody microtubule activity resembles plant cytokinesis in that interdigitating microtubules play a decisive role in the recruitment of cytokinetic vesicles and directing them towards the cytokinetic spaces which need to be plugged by fusing endosomes. Presently, we are approaching another turning point which brings cytokinesis in plant and animal cells even closer. As an unexpected twist, new studies reveal that both plant and animal cytokinesis is driven not so much by Golgi-derived vesicles but rather by homotypically and heterotypically fusing endosomes. These are generated from cytokinetic cortical sites defined by preprophase microtubules and contractile actomyosin ring, which induce local endocytosis of both the plasma membrane and cell wall material. Finally, plant and animal cytokinesis meet together at the physical separation of daughter cells despite obvious differences in their preparatory events.

  14. Medicinal Plant Recognition of Leaf Shape using Localized Arc Pattern Method

    Directory of Open Access Journals (Sweden)

    Ni Kadek Ayu Wirdiani

    2016-08-01

    Full Text Available Medicinal plants are plants that have benefit in order to supply the needs of families traditionally medicine. Medicinal plants have diverse types that causing modern society have difficulty in recognizing these crops. Medicinal plants generally can be identified by the leaves, stems and fruit. One of the leaves characteristics can be distinguished based on vein structure and shape of its. Based on these problem, plant recognition based on vein and shape are made by using Localized Arc Pattern Method. There are two important processes in Plant Recognition Applications. First process is Enrollment and the second is Recognition process. In the Enrolment process, the leaves image filed as many as 6 images for each leaves type. This image then calculated based on the 42 special model pattern obtained and the feature is stored as a reference image. Leaves images that used as test image are 200 images. On the Recognition process, the test image will be process which as same as at Enrollment process, however feature from the test image will be comparing with reference image in database, then it calculate the difference value. This process uses a threshold value to determine whether the test images leaves are recognized or not. When dissimilarity value is smaller than the threshold is known as the same leaves, when instead then it known as a different leaves or not known at all. Experiment result shows in this application can recognize 77% of total leaves and False Accepted Ratio (FAR equal to 4.5% and False Rejection Ratio (FRR equal to 18.5%. This result was influenced by the shiny surface of leaf and shape of the leaves are small.

  15. 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...

  16. The Nucleolonema of Plant and Animal Cells: A Comparison

    OpenAIRE

    Deltour, Roger; Motte, Patrick

    1990-01-01

    Depending on the author and the animal or plant origin of the material under study, the term "nucleolonema" is used in different contexts and thus indicates nucleolar ultrastructures that are different. In this paper, we attempt to clarify this state of affairs and to propose a definition for the plant cell nucleolonema. Peer reviewed

  17. 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

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

    Directory of Open Access Journals (Sweden)

    Feng Liu

    Full Text Available 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

  19. 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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue. In essence, plant cell expansion represents the foundation of development. Most studies of plant cell expansion...... have focused primarily upon late divergent multicellular land plants and specialized cell types (e.g., pollen tubes, root hairs). Here, we describe a unicellular green alga, Penium margaritaceum (Penium), which can serve as a valuable model organism for understanding cell expansion and the underlying...

  1. Deposition and alignment of cells on laser-patterned quartz

    Energy Technology Data Exchange (ETDEWEB)

    George, Sajan D., E-mail: sajan.george@manipal.edu [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Ladiwala, Uma, E-mail: brainwave@cbs.ac.in [UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Mumbai 400 098 (India); Thomas, John; Bankapur, Aseefhali; Chidangil, Santhosh [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Mathur, Deepak [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)

    2014-06-01

    Linear grooves have been laser-written on quartz surfaces using ultrashort (50 fs) pulses of 800 nm light. Measurements of water contact angle indicate that laser patterning makes the quartz surface more hydrophilic. Fibroblast cells were cultured on such laser-written surfaces; they were observed to align preferentially along the direction of the laser written grooves (width ∼2 μm. Raman spectroscopy results indicate that there are no chemical changes induced in the surface upon our laser writing. Most unexpectedly, there are also no chemical changes induced in the cells that are spatially aligned along the laser-written grooves. Atomic force microscopy measurements confirm that our laser-writing induces dramatic enhancement of surface roughness along the grooves, and the cells appear to respond to this. Thus, cell alignment seems to be in response to physical cues rather than chemical signals.

  2. Innate immune pattern recognition: a cell biological perspective.

    Science.gov (United States)

    Brubaker, Sky W; Bonham, Kevin S; Zanoni, Ivan; Kagan, Jonathan C

    2015-01-01

    Receptors of the innate immune system detect conserved determinants of microbial and viral origin. Activation of these receptors initiates signaling events that culminate in an effective immune response. Recently, the view that innate immune signaling events rely on and operate within a complex cellular infrastructure has become an important framework for understanding the regulation of innate immunity. Compartmentalization within this infrastructure provides the cell with the ability to assign spatial information to microbial detection and regulate immune responses. Several cell biological processes play a role in the regulation of innate signaling responses; at the same time, innate signaling can engage cellular processes as a form of defense or to promote immunological memory. In this review, we highlight these aspects of cell biology in pattern-recognition receptor signaling by focusing on signals that originate from the cell surface, from endosomal compartments, and from within the cytosol.

  3. Evaluating the Effects of Study Scale on Spatial Patterns of three Range Plant Species Using Quadrate Indices and Point Pattern Analysis in Chaharmahal- Bakhtirai Province Rangelands

    Directory of Open Access Journals (Sweden)

    M. Safaei

    2016-12-01

    Full Text Available This study aimed to investigate the spatial patterns of Acanthophyllum microcephalum Boiss, Nepeta glomerulosa Boiss and Hertia angustifolia and evaluate the effects of study scale on spatial patterns of three range plant species in Ghale-Gharak research-station located in Shahr-e-Kord. 40 points with a distance of five meters from each other were selected for sampling of vegetation along four 50 m transects using a random-systematic approach. The species spatial patterns were measured by 6 different distance-based methods including Hopkines, Johnson-and-Zimer, Eberhardt, Holgate, Hines and T-Square-index. A 100 m2 reference site (10 by 10 m was selected to record the species co-ordinates and conduct point pattern analysis. The spatial patterns of the species were determined in 3 scales of 10×10, 5×10 and 5×5 meters to highlight the effects of scale on spatial patterns of vegetation. According to the results, H. angustifolia showed randomized spatial patterns due to its seed dispersal ability. N. glomerulosa and A. microcephalum showed a clustered spatial pattern beacuse their seed are in achene form and fall next to these species. All the 3 species had a clustered pattern when the scale of point pattern analysis was decreased. Identifying these plant spatial patterns and their controlling factors such as seed dispersal mechanisms of the species and sampling scale are required to select the best sampling strategy in rangeland assessment programs.

  4. 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.

  5. Distribution pattern and conservation of threatened medicinal and aromatic plants of Central Himalaya, India

    Institute of Scientific and Technical Information of China (English)

    L. S. Kandari; K.S. Rao; R. K. Maikhuri; G. Kharkwal; K. Chauhan; C.P. Kala

    2011-01-01

    A study was conducted to examine the distribution pattern of four rhizomatous medicinal and aromatic plant species (MAPs) viz., Angelica glauca, Pleurospermum angelicoides, Rheum emodi and Arne- bia benthamii in different forest stands in Central Himalaya. Results show that A. Glauca and P. Angelicoides had a higher (50%) frequency at Chipkoan, Garpak and Phagati forest, R. Emodi had a higher (60%) fre- quency at Rishikund, Suki and Himtoli, and A. Benthamii had a higher (70%) frequency at Suki and Khambdhar The densities of A. Glauca (0.6 plants·m) and P. Angelicoides (0.5 plants·m) were higher at Chipkoan and Garpak sites than at other micro-sites, while densities of R. Emodi (0.8 plants·m) and A. Benthamii (1.0 plants·m) were higher at Suki and Khambdhar sites. A. Glauca had highest total basal covers (TBC) (1.2 cm·m) at Chipkoan, P. Angelicoides had highest TBC (0.92 cm·m) at Lati kharak site, A. Benthamii had the highest TBC (6.48 cm·m) at Khambdhar, and R. Emodi had highest TBC (4.53 cm·m) at Rishikund. For the four studied species, A. Glauca showed a contagious distribution, P. Angelicoides and R. Emodi showed the random and A. Benthamii showed the regular type of distribution.

  6. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Directory of Open Access Journals (Sweden)

    Hyeyeong Choe

    Full Text Available Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the

  7. Strong paleoclimatic legacies in current plant functional diversity patterns across Europe.

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2016-05-01

    Numerous studies indicate that environmental changes during the late Quaternary have elicited long-term disequilibria between species diversity and environment. Despite its importance for ecosystem functioning, the importance of historical environmental conditions as determinants of FD (functional diversity) remains largely unstudied. We quantified the geographic distributions of plant FD (richness and dispersion) across Europe using distribution and functional trait information for 2702 plant species. We then compared the importance of historical and contemporary factors to determine the relevance of past conditions as predictors of current plant FD in Europe. For this, we compared the strength of the relationships between FD with temperature and precipitation stability since the LGM (Last Glacial Maximum), accessibility to LGM refugia, and contemporary environmental conditions (climate, productivity, soil, topography, and land use). Functional richness and dispersion exhibited geographic patterns with strong associations to the environmental history of the region. The effect size of accessibility to LGM refugia and climate stability since the LGM was comparable to that of the contemporary predictors. Both functional richness and dispersion increased with temperature stability since the LGM and accessibility to LGM refugia. Functional richness' geographic pattern was primarily associated with accessibility to LGM refugia growing degree-days, land use heterogeneity, diversity of soil types, and absolute minimum winter temperature. Functional dispersion's geographic pattern was primarily associated with accessibility to LGM refugia growing degree-days and absolute minimum winter temperature. The high explained variance and model support of historical predictors are consistent with the idea that long-term variability in environmental conditions supplements contemporary factors in shaping FD patterns at continental scales. Given the importance of FD for ecosystem

  8. Polarity establishment, morphogenesis, and cultured plant cells in space

    Science.gov (United States)

    Krikorian, Abraham D.

    1989-01-01

    Plant development entails an orderly progression of cellular events both in terms of time and geometry. There is only circumstantial evidence that, in the controlled environment of the higher plant embryo sac, gravity may play a role in embryo development. It is still not known whether or not normal embryo development and differentiation in higher plants can be expected to take place reliably and efficiently in the micro g space environment. It seems essential that more attention be given to studying aspects of reproductive biology in order to be confident that plants will survive seed to seed to seed in a space environment. Until the time arrives when successive generations of plants can be grown, the best that can be done is utilize the most appropriate systems and begin, piece meal, to accumulate information on important aspects of plant reproduction. Cultured plant cells can play an important role in these activities since they can be grown so as to be morphogenetically competent, and thus can simulate those embryogenic events more usually identified with fertilized eggs in the embryo sac of the ovule in the ovary. Also, they can be manipulated with relative ease. The extreme plasticity of such demonstrably totipotent cell systems provides a means to test environmental effects such as micro g on a potentially free-running entity. The successful manipulation and management of plant cells and propagules in space also has significance for exploitation of biotechnologies in space since such systems, perforce, are an important vehicle whereby many genetic engineering manipulations are achieved.

  9. 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.

  10. Plant cell culture strategies for the production of natural products.

    Science.gov (United States)

    Ochoa-Villarreal, Marisol; Howat, Susan; Hong, SunMi; Jang, Mi Ok; Jin, Young-Woo; Lee, Eun-Kyong; Loake, Gary J

    2016-03-01

    Plants have evolved a vast chemical cornucopia to support their sessile lifestyles. Man has exploited this natural resource since Neolithic times and currently plant-derived chemicals are exploited for a myriad of applications. However, plant sources of most high-value natural products (NPs) are not domesticated and therefore their production cannot be undertaken on an agricultural scale. Further, these plant species are often slow growing, their populations limiting, the concentration of the target molecule highly variable and routinely present at extremely low concentrations. Plant cell and organ culture constitutes a sustainable, controllable and environmentally friendly tool for the industrial production of plant NPs. Further, advances in cell line selection, biotransformation, product secretion, cell permeabilisation, extraction and scale-up, among others, are driving increases in plant NP yields. However, there remain significant obstacles to the commercial synthesis of high-value chemicals from these sources. The relatively recent isolation, culturing and characterisation of cambial meristematic cells (CMCs), provides an emerging platform to circumvent many of these potential difficulties. [BMB Reports 2016; 49(3): 149-158].

  11. 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.

  12. From plants to animals; the role of plant cell death in ruminant herbivores.

    Science.gov (United States)

    Kingston-Smith, Alison H; Davies, Teri E; Edwards, Joan E; Theodorou, Michael K

    2008-01-01

    Plant cell death occurring as a result of adverse environmental conditions is known to limit crop production. It is less well recognized that plant cell death processes can also contribute to the poor environmental footprint of ruminant livestock production. Although the forage cells ingested by grazing ruminant herbivores will ultimately die, the lack of oxygen, elevated temperature, and challenge by microflora experienced in the rumen induce regulated plant stress responses resulting in DNA fragmentation and autolytic protein breakdown during the cell death process. Excessive ruminal proteolysis contributes to the inefficient conversion of plant to microbial and animal protein which results in up to 70% of the ingested nitrogen being returned to the land as the nitrogenous pollutants ammonia and urea. This constitutes a significant challenge for sustainable livestock production. As it is estimated that 25% of cultivated land worldwide is assigned to livestock production, it is clear that understanding the fundamental biology underlying cell death in ingested forage will have a highly significant role in minimizing the impact of human activities. This review examines our current understanding of plant metabolism in the rumen and explores opportunities for exploitation of plant genetics to advance sustainable land use.

  13. Shavenbaby couples patterning to epidermal cell shape control.

    Directory of Open Access Journals (Sweden)

    Hélène Chanut-Delalande

    2006-09-01

    Full Text Available It is well established that developmental programs act during embryogenesis to determine animal morphogenesis. How these developmental cues produce specific cell shape during morphogenesis, however, has remained elusive. We addressed this question by studying the morphological differentiation of the Drosophila epidermis, governed by a well-known circuit of regulators leading to a stereotyped pattern of smooth cells and cells forming actin-rich extensions (trichomes. It was shown that the transcription factor Shavenbaby plays a pivotal role in the formation of trichomes and underlies all examined cases of the evolutionary diversification of their pattern. To gain insight into the mechanisms of morphological differentiation, we sought to identify shavenbaby's downstream targets. We show here that Shavenbaby controls epidermal cell shape, through the transcriptional activation of different classes of cellular effectors, directly contributing to the organization of actin filaments, regulation of the extracellular matrix, and modification of the cuticle. Individual inactivation of shavenbaby's targets produces distinct trichome defects and only their simultaneous inactivation prevent trichome formation. Our data show that shavenbaby governs an evolutionarily conserved developmental module consisting of a set of genes collectively responsible for trichome formation, shedding new light on molecular mechanisms acting during morphogenesis and the way they can influence evolution of animal forms.

  14. Programmed cell death in C. elegans, mammals and plants.

    Science.gov (United States)

    Lord, Christina E N; Gunawardena, Arunika H L A N

    2012-08-01

    Programmed cell death (PCD) is the regulated removal of cells within an organism and plays a fundamental role in growth and development in nearly all eukaryotes. In animals, the model organism Caenorhabditis elegans (C. elegans) has aided in elucidating many of the pathways involved in the cell death process. Various analogous PCD processes can also be found within mammalian PCD systems, including vertebrate limb development. Plants and animals also appear to share hallmarks of PCD, both on the cellular and molecular level. Cellular events visualized during plant PCD resemble those seen in animals including: nuclear condensation, DNA fragmentation, cytoplasmic condensation, and plasma membrane shrinkage. Recently the molecular mechanisms involved in plant PCD have begun to be elucidated. Although few regulatory proteins have been identified as conserved across all eukaryotes, molecular features such as the participation of caspase-like proteases, Bcl-2-like family members and mitochondrial proteins appear to be conserved between plant and animal systems. Transgenic expression of mammalian and C. elegans pro- and anti-apoptotic genes in plants has been observed to dramatically influence the regulatory pathways of plant PCD. Although these genes often show little to no sequence similarity they can frequently act as functional substitutes for one another, thus suggesting that action may be more important than sequence resemblance. Here we present a summary of these findings, focusing on the similarities, between mammals, C. elegans, and plants. An emphasis will be placed on the mitochondria and its role in the cell death pathway within each organism. Through the comparison of these systems on both a cellular and molecular level we can begin to better understand PCD in plant systems, and perhaps shed light on the pathways, which are controlling the process. This manuscript adds to the field of PCD in plant systems by profiling apoptotic factors, to scale on a protein

  15. 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.

  16. 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.

  17. [Species-dependence of the pattern of plant photosynthetic rate response to light intensity transition from saturating to limiting one].

    Science.gov (United States)

    Chen, Yue; Xu, Da-Quan

    2007-12-01

    By observing the photosynthetic responses of leaves to changes in light intensity and CO(2) concentration it was found that among the more than 50 plant species examined 32 species and 25 species showed respectively the V pattern and L pattern of the photosynthetic response to light intensity transition from saturating to limiting one (Figs.1 and 2 and Table 1). The pattern of photosynthetic response to light intensity transition is species-dependent but not leaf developmental stage-dependent (Fig.3). The species-dependence was not related to classification in taxonomy because the photosynthetic response might display the two different patterns (V and L) in plants of the same family, for example, rice and wheat (Gramineae), soybean and peanut (Leguminosae). It seemed to be related to the pathway of photosynthetic carbon assimilation because all of the C(4) plants examined (maize, green bristlegrass and thorny amaranth) displayed the L pattern. It might be related to light environment where the plants originated. The V pattern of photosynthetic response to light intensity transition was often observed in some plants grown in shade habitats, for example, sweet viburnum and Japan fatsia, while the L pattern was frequently observed in those plants grown in sunny habitats, for example, ginkgo and cotton. Furthermore, the ratio of electron transport rate to carboxylation rate in vivo measured at limiting light was far higher in the V pattern plants (mostly higher than 10) than in the L pattern plants (mostly lower than 5), but the ratio measured at saturating light had no significant difference between the two kinds of plants (Table 2). These results can be explained in part by that the V pattern plant species have larger light-harvesting complex (LHCII) and at saturating light the reversible dissociation of some LHCIIs from PSII reaction center complex occurs. The pattern of photosynthetic response to light intensity transition and the ratio of electron transport rate

  18. Differential patterns of dehydroabietic acid biotransformation by Nicotiana tabacum and Catharanthus roseus cells.

    Science.gov (United States)

    Häkkinen, Suvi T; Lackman, Petri; Nygrén, Heli; Oksman-Caldentey, Kirsi-Marja; Maaheimo, Hannu; Rischer, Heiko

    2012-01-20

    The aim of this study was to use whole cell catalysts as tools for modification of selected resin acids in order to obtain value-added functional derivatives. The enzymatic bioconversion capacities of two plant species were tested towards dehydroabietic acid. Dehydroabietic acid (DHA) is an abundant resin acid in conifers, representing a natural wood protectant. It is also one of the constituents found in by-products of the kraft chemical pulping industry. DHA was fed to tobacco (Nicotiana tabacum) and Madagascar periwinkle (Catharanthus roseus) plant cell and tissue cultures and bioconversion product formation was monitored using NMR analysis. Both plant species took up DHA from culture medium, and various types of typical detoxification processes occurred in both cultures. In addition, diverse responses to DHA treatment were observed, including differences in uptake kinetics, chemical modification of added substrate and changes in overall metabolism of the cells. Interestingly, Catharanthus roseus, a host species for pharmaceutically valuable terpenoid indole alkaloids, exhibited a very different bioconversion pattern for exogenously applied DHA than tobacco, which does not possess a terpenoid indole pathway. In tobacco, DHA is readily glycosylated in the carbonyl group, whereas in periwinkle it is proposed that a cytochrome P450-catalyzed enzymatic detoxification reaction takes place before the formation of glycosylated product.

  19. Developmental patterning of glutamatergic synapses onto retinal ganglion cells

    Directory of Open Access Journals (Sweden)

    Schubert Timm

    2008-03-01

    Full Text Available Abstract Background Neurons receive excitatory synaptic inputs that are distributed across their dendritic arbors at densities and with spatial patterns that influence their output. How specific synaptic distributions are attained during development is not well understood. The distribution of glutamatergic inputs across the dendritic arbors of mammalian retinal ganglion cells (RGCs has long been correlated to the spatial receptive field profiles of these neurons. Thus, determining how glutamatergic inputs are patterned onto RGC dendritic arbors during development could provide insight into the cellular mechanisms that shape their functional receptive fields. Results We transfected developing and mature mouse RGCs with plasmids encoding fluorescent proteins that label their dendrites and glutamatergic postsynaptic sites. We found that as dendritic density (dendritic length per unit area of dendritic field decreases with maturation, the density of synapses along the dendrites increases. These changes appear coordinated such that RGCs attain the mature average density of postsynaptic sites per unit area (areal density by the time synaptic function emerges. Furthermore, stereotypic centro-peripheral gradients in the areal density of synapses across the arbor of RGCs are established at an early developmental stage. Conclusion The spatial pattern of glutamatergic inputs onto RGCs arises early in synaptogenesis despite ensuing reorganization of dendritic structure. We raise the possibility that these early patterns of synaptic distributions may arise from constraints placed on the number of contacts presynaptic neurons are able to make with the RGCs.

  20. 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.

  1. Global Splicing Pattern Reversion during Somatic Cell Reprogramming

    Directory of Open Access Journals (Sweden)

    Sho Ohta

    2013-10-01

    Full Text Available Alternative splicing generates multiple transcripts from a single gene, and cell-type-specific splicing profiles are important for the properties and functions of the cells. Recently, somatic cells have been shown to undergo dedifferentiation after the forced expression of transcription factors. However, it remains unclear whether somatic cell splicing is reorganized during reprogramming. Here, by combining deep sequencing with high-throughput absolute qRT-PCR, we show that somatic splicing profiles revert to pluripotent ones during reprogramming. Remarkably, the splicing pattern in pluripotent stem cells resembles that in testes, and the regulatory regions have specific characteristics in length and sequence. Furthermore, our siRNA screen has identified RNA-binding proteins that regulate splicing events in iPSCs. We have then demonstrated that two of the RNA-binding proteins, U2af1 and Srsf3, play a role in somatic cell reprogramming. Our results indicate that the drastic alteration in splicing represents part of the molecular network involved in the reprogramming process.

  2. 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.

  3. Structure and function of endosomes in plant cells.

    Science.gov (United States)

    Contento, Anthony L; Bassham, Diane C

    2012-08-01

    Endosomes are a heterogeneous collection of organelles that function in the sorting and delivery of internalized material from the cell surface and the transport of materials from the Golgi to the lysosome or vacuole. Plant endosomes have some unique features, with an organization distinct from that of yeast or animal cells. Two clearly defined endosomal compartments have been studied in plant cells, the trans-Golgi network (equivalent to the early endosome) and the multivesicular body (equivalent to the late endosome), with additional endosome types (recycling endosome, late prevacuolar compartment) also a possibility. A model has been proposed in which the trans-Golgi network matures into a multivesicular body, which then fuses with the vacuole to release its cargo. In addition to basic trafficking functions, endosomes in plant cells are known to function in maintenance of cell polarity by polar localization of hormone transporters and in signaling pathways after internalization of ligand-bound receptors. These signaling functions are exemplified by the BRI1 brassinosteroid hormone receptor and by receptors for pathogen elicitors that activate defense responses. After endocytosis of these receptors from the plasma membrane, endosomes act as a signaling platform, thus playing an essential role in plant growth, development and defense responses. Here we describe the key features of plant endosomes and their differences from those of other organisms and discuss the role of these organelles in cell polarity and signaling pathways.

  4. Fluids as Dynamic Templates for Cytoskeletal Proteins in Plant Cells

    CERN Document Server

    Lofthouse, J T

    2008-01-01

    The Dynamic Template model of biological cell membranes and the cytoplasm as spatially organised fluid layers is extended to plant cells, and is shown to offer a feasible shear driven mechanism for the co-alignment of internal and external fibres observed during growth and tropic responses

  5. 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....

  6. Plant organelle proteomics: collaborating for optimal cell function.

    Science.gov (United States)

    Agrawal, Ganesh Kumar; Bourguignon, Jacques; Rolland, Norbert; Ephritikhine, Geneviève; Ferro, Myriam; Jaquinod, Michel; Alexiou, Konstantinos G; Chardot, Thierry; Chakraborty, Niranjan; Jolivet, Pascale; Doonan, John H; Rakwal, Randeep

    2011-01-01

    Organelle proteomics describes the study of proteins present in organelle at a particular instance during the whole period of their life cycle in a cell. Organelles are specialized membrane bound structures within a cell that function by interacting with cytosolic and luminal soluble proteins making the protein composition of each organelle dynamic. Depending on organism, the total number of organelles within a cell varies, indicating their evolution with respect to protein number and function. For example, one of the striking differences between plant and animal cells is the plastids in plants. Organelles have their own proteins, and few organelles like mitochondria and chloroplast have their own genome to synthesize proteins for specific function and also require nuclear-encoded proteins. Enormous work has been performed on animal organelle proteomics. However, plant organelle proteomics has seen limited work mainly due to: (i) inter-plant and inter-tissue complexity, (ii) difficulties in isolation of subcellular compartments, and (iii) their enrichment and purity. Despite these concerns, the field of organelle proteomics is growing in plants, such as Arabidopsis, rice and maize. The available data are beginning to help better understand organelles and their distinct and/or overlapping functions in different plant tissues, organs or cell types, and more importantly, how protein components of organelles behave during development and with surrounding environments. Studies on organelles have provided a few good reviews, but none of them are comprehensive. Here, we present a comprehensive review on plant organelle proteomics starting from the significance of organelle in cells, to organelle isolation, to protein identification and to biology and beyond. To put together such a systematic, in-depth review and to translate acquired knowledge in a proper and adequate form, we join minds to provide discussion and viewpoints on the collaborative nature of organelles in

  7. Ectopic KNOX Expression Affects Plant Development by Altering Tissue Cell Polarity and Identity[OPEN

    Science.gov (United States)

    Rebocho, Alexandra B.

    2016-01-01

    Plant development involves two polarity types: tissue cell (asymmetries within cells are coordinated across tissues) and regional (identities vary spatially across tissues) polarity. Both appear altered in the barley (Hordeum vulgare) Hooded mutant, in which ectopic expression of the KNOTTED1-like Homeobox (KNOX) gene, BKn3, causes inverted polarity of differentiated hairs and ectopic flowers, in addition to wing-shaped outgrowths. These lemma-specific effects allow the spatiotemporal analysis of events following ectopic BKn3 expression, determining the relationship between KNOXs, polarity, and shape. We show that tissue cell polarity, based on localization of the auxin transporter SISTER OF PINFORMED1 (SoPIN1), dynamically reorients as ectopic BKn3 expression increases. Concurrently, ectopic expression of the auxin importer LIKE AUX1 and boundary gene NO APICAL MERISTEM is activated. The polarity of hairs reflects SoPIN1 patterns, suggesting that tissue cell polarity underpins oriented cell differentiation. Wing cell files reveal an anisotropic growth pattern, and computational modeling shows how polarity guiding growth can account for this pattern and wing emergence. The inverted ectopic flower orientation does not correlate with SoPIN1, suggesting that this form of regional polarity is not controlled by tissue cell polarity. Overall, the results suggest that KNOXs trigger different morphogenetic effects through interplay between tissue cell polarity, identity, and growth. PMID:27553356

  8. Ectopic KNOX Expression Affects Plant Development by Altering Tissue Cell Polarity and Identity.

    Science.gov (United States)

    Richardson, Annis Elizabeth; Rebocho, Alexandra B; Coen, Enrico S

    2016-08-23

    Plant development involves two polarity types: tissue cell (asymmetries within cells are coordinated across tissues) and regional (identities vary spatially across tissues) polarity. Both appear altered in the barley (Hordeum vulgare) Hooded mutant, in which ectopic expression of the KNOTTED1-like Homeobox (KNOX) gene, BKn3, causes inverted polarity of differentiated hairs and ectopic flowers, in addition to wing-shaped outgrowths. These lemma-specific effects allow the spatiotemporal analysis of events following ectopic BKn3 expression, determining the relationship between KNOXs, polarity, and shape. We show that tissue cell polarity, based on localization of the auxin transporter SISTER OF PINFORMED1 (SoPIN1), dynamically reorients as ectopic BKn3 expression increases. Concurrently, ectopic expression of the auxin importer LIKE AUX1 and boundary gene NO APICAL MERISTEM is activated. The polarity of hairs reflects SoPIN1 patterns, suggesting that tissue cell polarity underpins oriented cell differentiation. Wing cell files reveal an anisotropic growth pattern, and computational modeling shows how polarity guiding growth can account for this pattern and wing emergence. The inverted ectopic flower orientation does not correlate with SoPIN1, suggesting that this form of regional polarity is not controlled by tissue cell polarity. Overall, the results suggest that KNOXs trigger different morphogenetic effects through interplay between tissue cell polarity, identity, and growth.

  9. 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.

  10. Peroxisome Ca(2+) homeostasis in animal and plant cells.

    Science.gov (United States)

    Costa, Alex; Drago, Ilaria; Zottini, Michela; Pizzo, Paola; Pozzan, Tullio

    2013-01-01

    Ca(2+) homeostasis in peroxisomes has been an unsolved problem for many years. Recently novel probes to monitor Ca(2+) levels in the lumen of peroxisomes in living cells of both animal and plant cells have been developed. Here we discuss the contrasting results obtained in mammalian cells with chemiluminecsent (aequorin) and fluorescent (cameleon) probes targeted to peroxisomes. We briefly discuss the different characteristics of these probes and the possible pitfalls of the two approaches. We conclude that the contrasting results obtained with the two probes may reflect a heterogeneity among peroxisomes in mammalian cells. We also discuss the results obtained in plant peroxisomes. In particular we demonstrate that Ca(2+) increases in the cytoplasm are mirrored by similar rises of Ca(2+) concentration the lumen of peroxisomes. The increases in peroxisome Ca(2+) level results in the activation of a catalase isoform, CAT3. Other functional roles of peroxisomal Ca(2+) changes in plant physiology are briefly discussed.

  11. 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.

  12. Chitosan and polycaprolactone membranes patterned via electrospinning: effect of underlying chemistry and pattern characteristics on epithelial/fibroblastic cell behavior.

    Science.gov (United States)

    Simşek, Murat; Capkın, Merve; Karakeçili, Ayşe; Gümüşderelioğlu, Menemşe

    2012-12-01

    Electrospinning was used as an effective route to pattern chitosan (CS) and polycaprolactone (PCL) membranes with submicron fibers having different chemical structure (PCL or PCL/collagen) and physical characteristics (size: between ≈200 and 550 nm; randomly oriented or aligned form). While the PCL fibers with diameters in the same range (≈200 nm) were patterned on both of CS and PCL membranes to evaluate the influence of the underlying membrane chemistry, only CS membranes were patterned with PCL fibers having different sizes simply by changing the electrospinning conditions to investigate the effects of pattern characteristics. Furthermore, collagen was added to the PCL fiber structure to change the chemical composition of the fibers in a cell-attractive way. Two cell lines with different morphologies, fibroblastic MC3T3-E1 preosteoblasts and epithelial Madine Darby Bovine Kidney (MDBK) cells, were cultured on the patterned membranes. The observation of cellular behavior in terms of cell morphology and F-actin synthesis was realized by scanning electron microscopy and confocal microscopy analysis during the first 12 h of culture period. The viability of cells was controlled by MTT assay through 96 h of cell culture. The cell culture studies indicated that the leading aspect for the morphology change on patterned membranes was the fiber orientation. The aligned topography controlled the morphology of cells both on CS and PCL membranes. In the presence of collagen in the fiber structure, F-actin filament synthesis increased for MC3T3-E1 and MDBK cell lines.

  13. Pitfalls and possibilities in the analysis of biomass allocation patterns in plants

    Directory of Open Access Journals (Sweden)

    Hendrik ePoorter

    2012-12-01

    Full Text Available Plants can differentially allocate biomass to leaves, stems, roots and reproduction, and follow ontogenetic trajectories that interact with the prevailing climate. Various methodological tools exist to analyse the resulting allocation patterns, based either on the calculation of biomass ratios or fractions of different organs at a given point in time, or on a so-called allometric analysis of biomass data sampled across species or over an experimental growth period. We discuss the weak and strong points of each of these methods. Although both approaches have useful features, we suggest that often a plot of biomass fractions against total plant size, either across species or in the comparison of treatment effects, combines the best of both worlds.

  14. High Arctic plant phenology is determined by snowmelt patterns but duration of phenological periods is fixed

    DEFF Research Database (Denmark)

    Semenchuk, Philipp R.; Gillespie, Mark A K; Rumpf, Sabine B.;

    2016-01-01

    The duration of specific periods within a plant's life cycle are critical for plant growth and performance. In the High Arctic, the start of many of these phenological periods is determined by snowmelt date, which may change in a changing climate. It has been suggested that the end of these periods...... controls phenology and phenological period duration in High Arctic Svalbard using a melt timing gradient from natural and experimentally altered snow depths. We investigated the response of early- and late-season phenophases from both vegetative and reproductive phenological periods of eight common species....... We found that all phenophases follow snowmelt patterns, irrespective of timing of occurrence, vegetative or reproductive nature. Three of four phenological period durations based on these phenophases were fixed for most species, defining the studied species as periodic. Periodicity can thus...

  15. Large-Scale Evolutionary Patterns of Host Plant Associations in the Lepidoptera

    DEFF Research Database (Denmark)

    Menken, S.B.J.; Boomsma, J.J.; van Nieukerken, E.J.

    2010-01-01

    We characterized evolutionary patterns of host plant use across about 2500 species of British Lepidoptera, using character optimization and independent phylogenetic contrasts among 95 operational taxa, and evaluated the extent to which caterpillars are monophagous, use woody host plants, and feed...... concealed. We also analyzed the use of different Angiosperm superorders and related these associations to other key variables. The Nepticulidae, Pterophoridae, and Gracillariidae allowed explicit comparisons between the British fauna and the Lepidoptera worldwide, which indicated that our broad...... categorizations for Britain are accurate predictors for the global fauna. The first (lower glossatan) radiation of the Lepidoptera started with monophagous, internal feeding on woody Eurosids I. Polyphagy on nonwoody Eurosids I evolved together with the ability to feed externally, but did initially not produce...

  16. Adult plant development in triticale (× triticosecale wittmack) is controlled by dynamic genetic patterns of regulation.

    Science.gov (United States)

    Würschum, Tobias; Liu, Wenxin; Alheit, Katharina V; Tucker, Matthew R; Gowda, Manje; Weissmann, Elmar A; Hahn, Volker; Maurer, Hans Peter

    2014-09-18

    Many biologically and agronomically important traits are dynamic and show temporal variation. In this study, we used triticale (× Triticosecale Wittmack) as a model crop to assess the genetic dynamics underlying phenotypic plasticity of adult plant development. To this end, a large mapping population with 647 doubled haploid lines derived from four partially connected families from crosses among six parents was scored for developmental stage at three different time points. Using genome-wide association mapping, we identified main effect and epistatic quantitative trait loci (QTL) at all three time points. Interestingly, some of these QTL were identified at all time points, whereas others appear to only contribute to the genetic architecture at certain developmental stages. Our results illustrate the temporal contribution of QTL to the genetic control of adult plant development and more generally, the temporal genetic patterns of regulation that underlie dynamic traits.

  17. Divergence in plant and microbial allocation strategies explains continental patterns in microbial allocation and biogeochemical fluxes.

    Science.gov (United States)

    Averill, Colin

    2014-10-01

    Allocation trade-offs shape ecological and biogeochemical phenomena at local to global scale. Plant allocation strategies drive major changes in ecosystem carbon cycling. Microbial allocation to enzymes that decompose carbon vs. organic nutrients may similarly affect ecosystem carbon cycling. Current solutions to this allocation problem prioritise stoichiometric tradeoffs implemented in plant ecology. These solutions may not maximise microbial growth and fitness under all conditions, because organic nutrients are also a significant carbon resource for microbes. I created multiple allocation frameworks and simulated microbial growth using a microbial explicit biogeochemical model. I demonstrate that prioritising stoichiometric trade-offs does not optimise microbial allocation, while exploiting organic nutrients as carbon resources does. Analysis of continental-scale enzyme data supports the allocation patterns predicted by this framework, and modelling suggests large deviations in soil C loss based on which strategy is implemented. Therefore, understanding microbial allocation strategies will likely improve our understanding of carbon cycling and climate.

  18. Using phylogenomic patterns and gene ontology to identify proteins of importance in plant evolution.

    Science.gov (United States)

    Cibrián-Jaramillo, Angélica; De la Torre-Bárcena, Jose E; Lee, Ernest K; Katari, Manpreet S; Little, Damon P; Stevenson, Dennis W; Martienssen, Rob; Coruzzi, Gloria M; DeSalle, Rob

    2010-07-12

    We use measures of congruence on a combined expressed sequenced tag genome phylogeny to identify proteins that have potential significance in the evolution of seed plants. Relevant proteins are identified based on the direction of partitioned branch and hidden support on the hypothesis obtained on a 16-species tree, constructed from 2,557 concatenated orthologous genes. We provide a general method for detecting genes or groups of genes that may be under selection in directions that are in agreement with the phylogenetic pattern. Gene partitioning methods and estimates of the degree and direction of support of individual gene partitions to the overall data set are used. Using this approach, we correlate positive branch support of specific genes for key branches in the seed plant phylogeny. In addition to basic metabolic functions, such as photosynthesis or hormones, genes involved in posttranscriptional regulation by small RNAs were significantly overrepresented in key nodes of the phylogeny of seed plants. Two genes in our matrix are of critical importance as they are involved in RNA-dependent regulation, essential during embryo and leaf development. These are Argonaute and the RNA-dependent RNA polymerase 6 found to be overrepresented in the angiosperm clade. We use these genes as examples of our phylogenomics approach and show that identifying partitions or genes in this way provides a platform to explain some of the more interesting organismal differences among species, and in particular, in the evolution of plants.

  19. 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.

  20. 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.

  1. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotides...... probes (monoclonal antibodies mAbs and carbohydrate binding modules, CBMs) to rapidly profile polysaccharides across a sample set. During my PhD I have further developed the CoMPP technique and used it for cell wall analysis within the context of a variety of applied and fundamental projects. The data...... produced has provided new insight into cell wall evolution and biosynthesis and has contributed to the commercial development of cell wall materials. A major focus of the work has been the wide scale sampling of cell wall diversity across the plant kingdom, from unicellular algae to highly evolved...

  2. Abundantly and rarely expressed Lhc protein genes exhibit distinct regulation patterns in plants.

    Science.gov (United States)

    Klimmek, Frank; Sjödin, Andreas; Noutsos, Christos; Leister, Dario; Jansson, Stefan

    2006-03-01

    We have analyzed gene regulation of the Lhc supergene family in poplar (Populus spp.) and Arabidopsis (Arabidopsis thaliana) using digital expression profiling. Multivariate analysis of the tissue-specific, environmental, and developmental Lhc expression patterns in Arabidopsis and poplar was employed to characterize four rarely expressed Lhc genes, Lhca5, Lhca6, Lhcb7, and Lhcb4.3. Those genes have high expression levels under different conditions and in different tissues than the abundantly expressed Lhca1 to 4 and Lhcb1 to 6 genes that code for the 10 major types of higher plant light-harvesting proteins. However, in some of the datasets analyzed, the Lhcb4 and Lhcb6 genes as well as an Arabidopsis gene not present in poplar (Lhcb2.3) exhibited minor differences to the main cooperative Lhc gene expression pattern. The pattern of the rarely expressed Lhc genes was always found to be more similar to that of PsbS and the various light-harvesting-like genes, which might indicate distinct physiological functions for the rarely and abundantly expressed Lhc proteins. The previously undetected Lhcb7 gene encodes a novel plant Lhcb-type protein that possibly contains an additional, fourth, transmembrane N-terminal helix with a highly conserved motif. As the Lhcb4.3 gene seems to be present only in Eurosid species and as its regulation pattern varies significantly from that of Lhcb4.1 and Lhcb4.2, we conclude it to encode a distinct Lhc protein type, Lhcb8.

  3. 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].

  4. Plant species affect colonization patterns and metabolic activity of associated endophytes during phytoremediation of crude oil-contaminated soil.

    Science.gov (United States)

    Fatima, K; Imran, A; Amin, I; Khan, Q M; Afzal, M

    2016-04-01

    Plants coupled with endophytic bacteria hold great potential for the remediation of polluted environment. The colonization patterns and activity of inoculated endophytes in rhizosphere and endosphere of host plant are among the primary factors that may influence the phytoremediation process. However, these colonization patterns and metabolic activity of the inoculated endophytes are in turn controlled by none other than the host plant itself. The present study aims to determine such an interaction specifically for plant-endophyte systems remediating crude oil-contaminated soil. A consortium (AP) of two oil-degrading endophytic bacteria (Acinetobacter sp. strain BRSI56 and Pseudomonas aeruginosa strain BRRI54) was inoculated to two grasses, Brachiaria mutica and Leptochloa fusca, vegetated in crude oil-contaminated soil. Colonization patterns and metabolic activity of the endophytes were monitored in the rhizosphere and endosphere of the plants. Bacterial augmentation enhanced plant growth and crude oil degradation. Maximum crude oil degradation (78%) was achieved with B. mutica plants inoculated with AP consortium. This degradation was significantly higher than those treatments, where plants and bacteria were used individually or L. fusca and endophytes were used in combination. Moreover, colonization and metabolic activity of the endophytes were higher in the rhizosphere and endosphere of B. mutica than L. fusca. The plant species affected not only colonization pattern and biofilm formation of the inoculated bacteria in the rhizosphere and endosphere of the host plant but also affected the expression of alkane hydroxylase gene, alkB. Hence, the investigation revealed that plant species can affect colonization patterns and metabolic activity of inoculated endophytic bacteria and ultimately the phytoremediation process.

  5. Patterning of cell assemblies regulated by adhesion receptors of the cadherin superfamily.

    OpenAIRE

    2000-01-01

    During morphogenesis, cell-cell association patterns are dynamically altered. We are interested in how cell adhesion molecules can regulate the patterning of cellular assemblies. Cadherins, a group of cell-cell adhesion receptors, are crucial for the organized assembly of many cell types, but they also regulate dynamic aspects of cell association. For example, during neural crest emigration from the neural tube, the cadherin subtypes expressed by crest cells are switched from one subtype to a...

  6. Are kinesins required for organelle trafficking in plant cells?

    Directory of Open Access Journals (Sweden)

    Giampiero eCai

    2012-07-01

    Full Text Available Plant cells exhibit active movement of membrane-bounded materials, which is more pronounced in large cells but is also appreciable in medium-sized cells and in tip-growing cells (such as pollen tubes and root hairs. Trafficking of organelles (such as Golgi bodies, endoplasmic reticulum, peroxisomes, and mitochondria and vesicles is essential for plant cell physiology and allows a more or less homogeneous distribution of the cell content. It is well established that the long-range trafficking of organelles is dependent essentially on the network of actin filaments and is powered by the enzyme activity of myosins. However, some lines of evidence suggest that microtubules and members of the kinesin microtubule-based motor superfamily might have a role in the positioning and/or short-range movement of cell organelles and vesicles. Data collected in different cells (such as trichomes and pollen tubes, in specific stages of the plant cell life cycle (for example during phragmoplast development and for different organelle classes (mitochondria, Golgi bodies and chloroplasts encourage the hypothesis that microtubule-based motors might play subtle yet unclarified roles in organelle trafficking. In some cases, this function could be carried out in cooperation with actin filaments according to the model of functional cooperation by which motors of different families are associated with the organelle surface. Since available data did not provide an unambiguous conclusion with regard to the role of kinesins in organelle transport, here we want to debate such hypothesis.

  7. Above–belowground herbivore interactions in mixed plant communities are influenced by altered precipitation patterns

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2016-03-01

    belowground decreased aphid numbers by 30%, likely associated with a significant reduction in proline in weevil-treated lucerne plants. This study demonstrates how predicted changes to precipitation patterns and indirect interactions between herbivores can alter the outcome of competition between N-fixing legumes and non-N-fixing grasses, with important implications for plant community structure and productivity.

  8. Patterning methods for polymers in cell and tissue engineering.

    Science.gov (United States)

    Kim, Hong Nam; Kang, Do-Hyun; Kim, Min Sung; Jiao, Alex; Kim, Deok-Ho; Suh, Kahp-Yang

    2012-06-01

    Polymers provide a versatile platform for mimicking various aspects of physiological extracellular matrix properties such as chemical composition, rigidity, and topography for use in cell and tissue engineering applications. In this review, we provide a brief overview of patterning methods of various polymers with a particular focus on biocompatibility and processability. The materials highlighted here are widely used polymers including thermally curable polydimethyl siloxane, ultraviolet-curable polyurethane acrylate and polyethylene glycol, thermo-sensitive poly(N-isopropylacrylamide) and thermoplastic and conductive polymers. We also discuss how micro- and nanofabricated polymeric substrates of tunable elastic modulus can be used to engineer cell and tissue structure and function. Such synergistic effect of topography and rigidity of polymers may be able to contribute to constructing more physiologically relevant microenvironment.

  9. Effects of increased snow on growth response and allocation patterns of arctic plants

    Science.gov (United States)

    Addis, C. E.; Bret-Harte, M. S.

    2013-12-01

    Warming in the Arctic has led to an increase in shrub cover on the tundra that has been well documented in arctic Alaska. Fall and winter precipitation are also predicted to increase in arctic regions under continued climate change, resulting in greater snow depths and insulating winter soil, thus facilitating overwinter nitrogen mineralization by microbes. We predict that this increased microbial activity will enhance plant growth because more nutrients will be available for plant uptake at spring thaw. We studied the effect of increased snow on plant growth and nutrient allocation patterns using snow fences located across a gradient of shrub height and density at Toolik Field Station on the north slope of Alaska's Brooks Range. We compared growth and nutrient content of deciduous shrubs, evergreen shrubs, and graminoids on either side of the fences. Species behaved individualistically, with some showing increased growth with snow addition, others showing decreased growth, and some showing no effect of snow at all. The biggest increases in growth were seen in deciduous shrubs, particularly Salix pulchra, due to increases in secondary, or radial, growth which allowed plants to support more branches and thus more leaves. This provides a preliminary mechanistic explanation for the widespread increase in shrub cover across the northern latitudes. In addition, species that experienced increases in biomass due to snow also generally displayed increased nitrogen and carbon content in both leaves and stems, indicating that plants which got bigger were also better able to capture available resources. We conclude that faster growing species with the ability to respond rapidly to changes in nutrient availability will likely dominate under continued climate change, and may alter important ecosystem processes such as carbon and nitrogen storage.

  10. Long-term spatial pattern change in a semi-arid plant community: The role of climate and composition

    Science.gov (United States)

    Brooker, Rob W.; Matesanz, Silvia; Valladares, Fernando; Klotz, Stefan

    2012-11-01

    The spatial pattern of plant communities can be an indicator of the processes that regulate community structure and their interplay with environmental drivers such as climate. However, to exploit such indicators we need a fuller understanding of the links between spatial pattern and climate. We examined variation in spatial pattern of annuals/biennials and perennials in a range margin steppic plant community in Germany over 26 years. We assessed change in spatial pattern through time, and how this change was related to local variation in climate and community composition. We found increasing dissociation between annuals/biennials and perennials through time, and a response of spatial pattern to summer temperature and precipitation. These responses are associated with the occurrence of Centaurea stoebe, a species which establishes in the community mid-way through the recording period. Our results indicate that in some circumstances spatial patterning of vegetation may not be directly linked to environmental severity, and that species turnover rather than changes in the interactions or abundance of species already in the community can influence the observed dynamics of vegetation spatial pattern. Thus, they support calls for a better understanding of the context-specificity of plant-plant interactions, their translation to spatial pattern, and their regulation by climate and other drivers such as species turnover.

  11. 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.

  12. How do filamentous pathogens deliver effector proteins into plant cells?

    Directory of Open Access Journals (Sweden)

    Benjamin Petre

    2014-02-01

    Full Text Available Fungal and oomycete plant parasites are among the most devastating pathogens of food crops. These microbes secrete effector proteins inside plant cells to manipulate host processes and facilitate colonization. How these effectors reach the host cytoplasm remains an unclear and debated area of plant research. In this article, we examine recent conflicting findings that have generated discussion in the field. We also highlight promising approaches based on studies of both parasite and host during infection. Ultimately, this knowledge may inform future broad spectrum strategies for protecting crops from such pathogens.

  13. How Do Filamentous Pathogens Deliver Effector Proteins into Plant Cells?

    Science.gov (United States)

    Petre, Benjamin; Kamoun, Sophien

    2014-01-01

    Fungal and oomycete plant parasites are among the most devastating pathogens of food crops. These microbes secrete effector proteins inside plant cells to manipulate host processes and facilitate colonization. How these effectors reach the host cytoplasm remains an unclear and debated area of plant research. In this article, we examine recent conflicting findings that have generated discussion in the field. We also highlight promising approaches based on studies of both parasite and host during infection. Ultimately, this knowledge may inform future broad spectrum strategies for protecting crops from such pathogens. PMID:24586116

  14. Compost in plant microbial fuel cell for bioelectricity generation.

    Science.gov (United States)

    Moqsud, M A; Yoshitake, J; Bushra, Q S; Hyodo, M; Omine, K; Strik, David

    2015-02-01

    Recycling of organic waste is an important topic in developing countries as well as developed countries. Compost from organic waste has been used for soil conditioner. In this study, an experiment has been carried out to produce green energy (bioelectricity) by using paddy plant microbial fuel cells (PMFCs) in soil mixed with compost. A total of six buckets filled with the same soil were used with carbon fiber as the electrodes for the test. Rice plants were planted in five of the buckets, with the sixth bucket containing only soil and an external resistance of 100 ohm was used for all cases. It was observed that the cells with rice plants and compost showed higher values of voltage and power density with time. The highest value of voltage showed around 700 mV when a rice plant with 1% compost mixed soil was used, however it was more than 95% less in the case of no rice plant and without compost. Comparing cases with and without compost but with the same number of rice plants, cases with compost depicted higher voltage to as much as 2 times. The power density was also 3 times higher when the compost was used in the paddy PMFCs which indicated the influence of compost on bio-electricity generation.

  15. Gene Delivery into Plant Cells for Recombinant Protein Production

    Directory of Open Access Journals (Sweden)

    Qiang Chen

    2015-01-01

    Full Text Available Recombinant proteins are primarily produced from cultures of mammalian, insect, and bacteria cells. In recent years, the development of deconstructed virus-based vectors has allowed plants to become a viable platform for recombinant protein production, with advantages in versatility, speed, cost, scalability, and safety over the current production paradigms. In this paper, we review the recent progress in the methodology of agroinfiltration, a solution to overcome the challenge of transgene delivery into plant cells for large-scale manufacturing of recombinant proteins. General gene delivery methodologies in plants are first summarized, followed by extensive discussion on the application and scalability of each agroinfiltration method. New development of a spray-based agroinfiltration and its application on field-grown plants is highlighted. The discussion of agroinfiltration vectors focuses on their applications for producing complex and heteromultimeric proteins and is updated with the development of bridge vectors. Progress on agroinfiltration in Nicotiana and non-Nicotiana plant hosts is subsequently showcased in context of their applications for producing high-value human biologics and low-cost and high-volume industrial enzymes. These new advancements in agroinfiltration greatly enhance the robustness and scalability of transgene delivery in plants, facilitating the adoption of plant transient expression systems for manufacturing recombinant proteins with a broad range of applications.

  16. 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.

  17. 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.

  18. Liquid Crystal Pre-Patterning for Cell Division

    Science.gov (United States)

    Hill, Nicholas; Mottram, Nigel; Lydon, John

    2005-11-01

    We are examining the hypothesis that the overall geometry of mitosis is determined by liquid-crystal pre-patterning of the cytoplasm. The identification of mitosis with liquid crystalline (LX) phases is at least 50 years old but no attempt has been made to propose a detailed theory, presumably because of the difficulties in applying a theory of liquid crystals (LCs) in a 3D geometry. In this work, we use a mathematical model (Q-tensor theory) of a nematic LC for the cytoplasm of the cell and solve this numerically to show that the geometry of the prophase and metaphase can be explained using LX phases. The pre-patterning for the spindle is regarded as a bipolar LX assembly with the centrosomes acting as LC poles (centres of LX defects). The centrosomes and the nuclear envelope are both treated as bodies submerged in the LC medium between two spherical shells (the nuclear and cell membranes). The geometries considered are novel and 3D.

  19. 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.

  20. Role of the plant cell wall in gravity resistance.

    Science.gov (United States)

    Hoson, Takayuki; Wakabayashi, Kazuyuki

    2015-04-01

    Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, comparable to gravitropism. The cell wall is responsible for the final step of gravity resistance. The gravity signal increases the rigidity of the cell wall via the accumulation of its constituents, polymerization of certain matrix polysaccharides due to the suppression of breakdown, stimulation of cross-link formation, and modifications to the wall environment, in a wide range of situations from microgravity in space to hypergravity. Plants thus develop a tough body to resist the gravitational force via an increase in cell wall rigidity and the modification of growth anisotropy. The development of gravity resistance mechanisms has played an important role in the acquisition of responses to various mechanical stresses and the evolution of land plants.

  1. Optical Property Analyses of Plant Cells for Adaptive Optics Microscopy

    Science.gov (United States)

    Tamada, Yosuke; Murata, Takashi; Hattori, Masayuki; Oya, Shin; Hayano, Yutaka; Kamei, Yasuhiro; Hasebe, Mitsuyasu

    2014-04-01

    In astronomy, adaptive optics (AO) can be used to cancel aberrations caused by atmospheric turbulence and to perform diffraction-limited observation of astronomical objects from the ground. AO can also be applied to microscopy, to cancel aberrations caused by cellular structures and to perform high-resolution live imaging. As a step toward the application of AO to microscopy, here we analyzed the optical properties of plant cells. We used leaves of the moss Physcomitrella patens, which have a single layer of cells and are thus suitable for optical analysis. Observation of the cells with bright field and phase contrast microscopy, and image degradation analysis using fluorescent beads demonstrated that chloroplasts provide the main source of optical degradations. Unexpectedly, the cell wall, which was thought to be a major obstacle, has only a minor effect. Such information provides the basis for the application of AO to microscopy for the observation of plant cells.

  2. Plant cell, tissue and organ culture: the most flexible foundations for plant metabolic engineering applications.

    Science.gov (United States)

    Ogita, Shinjiro

    2015-05-01

    Significant advances in plant cell, tissue and organ culture (PCTOC) have been made in the last five decades. PCTOC is now thought to be the underlying technique for understanding general or specific biological functions of the plant kingdom, and it is one of the most flexible foundations for morphological, physiological and molecular biological applications of plants. Furthermore, the recent advances in the field of information technology (IT) have enabled access to a large amount of information regarding all aspects of plant biology. For example, sequencing information is stored in mega repositories such as the National Center for Biotechnology Information (NCBI), which can be easily accessed by researchers worldwide. To date, the PCTOC and IT combination strategy for regulation of target plant metabolism and the utilization of bioactive plant metabolites for commercial purposes is essential. In this review, the advantages and the limitations of these methodologies, especially regarding the production of bioactive plant secondary metabolites and metabolic engineering in target plants are discussed mainly from the phenotypic view point.

  3. External serial connection without layer patterning for organic solar cells

    Science.gov (United States)

    Wong, Ying Qian; Wong, Hin Yong; Tan, Ching Seong; Meng, Hsin-Fei

    2016-12-01

    This paper proposes a novel alternative to conventional internal serial connection, where precise patterning and scribing of organic layers can be eliminated. Adjacent cells can be made nearer for better space-utilization and higher voltages per unit area. Also, blade coating is proposed as the fabrication method as it has low material wastage (less than 5%), easily scalable to large area, has high film uniformity and has high throughput due to its roll-to-roll potential. This paper demonstrates 3-cells large area (12.98 cm2) external serial connection organic solar cells (OSCs) using the material poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) and 2,6-Bis(trimethyltin)-4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b']dithiophene:6,6-phenyl C71-butyric acid methyl ester (PBDTTT-CT:PC71BM) respectively. The power conversion efficiencies (PCEs) of the resulting 3-cells modules are 2.0% and 4.1% respectively.

  4. A comparative genome analysis of PME and PMEI families reveals the evolution of pectin metabolism in plant cell walls.

    Science.gov (United States)

    Wang, Maojun; Yuan, Daojun; Gao, Wenhui; Li, Yang; Tan, Jiafu; Zhang, Xianlong

    2013-01-01

    Pectins are fundamental polysaccharides in the plant primary cell wall. Pectins are synthesized and secreted to cell walls as highly methyl-esterified polymers and then demethyl-esterified by pectin methylesterases (PMEs), which are spatially regulated by pectin methylesterase inhibitors (PMEIs). Although PME and PMEI genes are pivotal in plant cell wall formation, few studies have focused on the evolutionary patterns of the PME and PMEI gene families. In this study, the gene origin, evolution, and expression diversity of these two families were systematically analyzed using 11 representative species, including algae, bryophytes, lycophytes and flowering land plants. The results show that 1) for the two subfamilies (PME and proPME) of PME, the origin of the PME subfamily is consistent with the appearance of pectins in early charophyte cell walls, 2) Whole genome duplication (WGD) and tandem duplication contribute to the expansion of proPME and PMEI families in land plants, 3) Evidence of selection pressure shows that the proPME and PMEI families have rapidly evolved, particularly the PMEI family in vascular plants, and 4) Comparative expression profile analysis of the two families indicates that the eudicot Arabidopsis and monocot rice have different expression patterns. In addition, the gene structure and sequence analyses show that the origin of the PMEI domain may be derived from the neofunctionalization of the pro domain after WGD. This study will advance the evolutionary understanding of the PME and PMEI families and plant cell wall development.

  5. 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.

  6. Microanalysis of Plant Cell Wall Polysaccharides

    NARCIS (Netherlands)

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

    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 s

  7. 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

  8. Apple proliferation phytoplasma influences the pattern of plant volatiles emitted depending on pathogen virulence

    Directory of Open Access Journals (Sweden)

    Margit eRid

    2016-01-01

    Full Text Available Apple proliferation (AP and pear decline (PD are the most severe diseases in pome fruit growing areas. AP-infected trees show typical symptoms such as witches’ broom, enlarged stipules, tasteless and dwarf fruits. PD-infected pears show a progressive weakening, reduced terminal growth, smaller fruits and die within weeks (quick decline or years (slow decline. The diseases are caused by the cell-wall lacking bacteria Candidatus Phytoplasma mali (AP phytoplasma and Ca. P. pyri (PD phytoplasma, respectively. In previous studies it has been shown that AP-infected apple trees emitted higher amounts of the sesquiterpene β-caryophyllene, an attractant of the insect vector Cacopsylla picta (Hemiptera: Psyllidae, thereby facilitating the dispersal of AP phytoplasma. In the present study, volatile organic compounds (VOCs occurring in the headspace of plants infected with Ca. P. mali strains causing different severity of symptoms in apple plants were collected, analyzed and identified. Headspace samples from healthy and AP-infected model plant tobacco (Nicotiana occidentalis and apple (Malus domestica as well as from healthy and PD-infected pear (Pyrus communis were investigated via thermodesorption and GC-MS analysis. Significantly higher concentrations of ethyl benzoate were produced in all phytoplasma-infected plants compared to healthy ones and an as yet unidentified sesquiterpene differed between the odor bouquets of healthy and by Ca. P. mali infected tobacco plants. Additionally, statistically significant higher amounts of both compounds were measured in the headspace of plants infected by the virulent AP strain. In apple, significantly higher concentrations of ethyl benzoate and methyl salicylate were observed for trees infected with strains of Ca. P. mali. Ethyl benzoate was also detected in the headspace of pear trees infected with Ca. P. pyri.

  9. 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

  10. Calcium signaling in plant cells in altered gravity

    Science.gov (United States)

    Kordyum, E. L.

    2003-10-01

    Changes in the intracellular Ca 2+ concentration in altered gravity (microgravity and clinostating) evidence that Ca 2+ signaling can play a fundamental role in biological effects of microgravity. Calcium as a second messenger is known to play a crucial role in stimulus - response coupling for many plant cellular signaling pathways. Its messenger functions are realized by transient changes in the cytosolic ion concentration induced by a variety of internal and external stimuli such as light, hormones, temperature, anoxia, salinity, and gravity. Although the first data on the changes in the calcium balance in plant cells under the influence of altered gravity have appeared in 80 th, a review highlighting the performed research and the possible significance of such Ca 2+ changes in the structural and metabolic rearrangements of plant cells in altered gravity is still lacking. In this paper, an attempt was made to summarize the available experimental results and to consider some hypotheses in this field of research. It is proposed to distinguish between cell gravisensing and cell graviperception; the former is related to cell structure and metabolism stability in the gravitational field and their changes in microgravity (cells not specialized to gravity perception), the latter is related to active use of a gravitational stimulus by cells presumebly specialized to gravity perception for realization of normal space orientation, growth, and vital activity (gravitropism, gravitaxis) in plants. The main experimental data concerning both redistribution of free Ca 2+ ions in plant cell organelles and the cell wall, and an increase in the intracellular Ca 2+ concentration under the influence of altered gravity are presented. Based on the gravitational decompensation hypothesis, the consequence of events occurring in gravisensing cells not specialized to gravity perception under altered gravity are considered in the following order: changes in the cytoplasmic membrane surface

  11. Plant Cell Division Analyzed by Transient Agrobacterium-Mediated Transformation of Tobacco BY-2 Cells.

    Science.gov (United States)

    Buschmann, Henrik

    2016-01-01

    The continuing analysis of plant cell division will require additional protein localization studies. This is greatly aided by GFP-technology, but plant transformation and the maintenance of transgenic lines can present a significant technical bottleneck. In this chapter I describe a method for the Agrobacterium-mediated genetic transformation of tobacco BY-2 cells. The method allows for the microscopic analysis of fluorescence-tagged proteins in dividing cells in within 2 days after starting a coculture. This transient transformation procedure requires only standard laboratory equipment. It is hoped that this rapid method would aid researchers conducting live-cell localization studies in plant mitosis and cytokinesis.

  12. Patterns of sugar feeding and host plant preferences in adult males of An. gambiae (Diptera: Culicidae).

    Science.gov (United States)

    Gouagna, Louis-Clément; Poueme, Rodrigue S; Dabiré, Kounbobr Roch; Ouédraogo, Jean-Bosco; Fontenille, Didier; Simard, Frédéric

    2010-12-01

    Sugar feeding by male mosquitoes is critical for their success in mating competition. However, the facets of sugar source finding under natural conditions remain unknown. Here, evidence obtained in Western Burkina Faso indicated that the distribution of An. gambiae s.s. (M and S molecular forms) males across different peri-domestic habitats is dependent on the availability of potential sugar sources from which they obtain more favorable sites for feeding or resting. Among field-collected anophelines, a higher proportion of specimens containing fructose were found on flowering Mangifera indica (Anacardiaceae), Dolonix regia (Fabaceae), Thevetia neriifolia (Apocynaceae), Senna siamea, and Cassia sieberiana (both Fabaceae) compared to that recorded on other nearby plants, suggesting that some plants are favored for use as a sugar source over others. Y-tube olfactometer assays with newly-emerged An. gambiae s.s. exposed to odors from individual plants and some combinations thereof showed that males use odor cues to guide their preference. The number of sugar-positive males was variable in a no-choice cage assay, consistent with the olfactory response patterns towards corresponding odor stimuli. These experiments provide the first evidence both in field and laboratory conditions for previously unstudied interactions between males of An. gambiae and natural sugar sources.

  13. 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.

  14. 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.

  15. Endogenous electromagnetic fields in plant leaves: a new hypothesis for vascular pattern formation.

    Science.gov (United States)

    Pietak, Alexis Mari

    2011-06-01

    Electromagnetic (EM) phenomena have long been implicated in biological development, but few detailed, practical mechanisms have been put forth to connect electromagnetism with morphogenetic processes. This work describes a new hypothesis for plant leaf veination, whereby an endogenous electric field forming as a result of a coherent Frohlich process, and corresponding to an EM resonant mode of the developing leaf structure, is capable of instigating leaf vascularisation. In order to test the feasibility of this hypothesis, a three-dimensional, EM finite-element model (FEM) of a leaf primordium was constructed to determine if suitable resonant modes were physically possible for geometric and physical parameters similar to those of developing leaf tissue. Using the FEM model, resonant EM modes with patterns of relevance to developing leaf vein modalities were detected. On account of the existence of shared geometric signatures in a leaf's vascular pattern and the electric field component of EM resonant modes supported by a developing leaf structure, further theoretical and experimental investigations are warranted. Significantly, this hypothesis is not limited to leaf vascular patterning, but may be applicable to a variety of morphogenetic phenomena in a number of living systems.

  16. Diversity of fecal coliforms and their antimicrobial resistance patterns in wastewater treatment model plant.

    Science.gov (United States)

    Luczkiewicz, A; Fudala-Ksiazek, S; Jankowska, K; Quant, B; Olańczuk-Neyman, K

    2010-01-01

    The occurrence of resistance patterns among wastewater fecal coliforms was determined in the study. Susceptibility of the isolates was tested against 19 antimicrobial agents: aminoglycosides, aztreonam, carbapenems, cephalosporines, beta-lactam/beta-lactamase inhibitors, penicillines, tetracycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. Additionally the removal of resistant isolates was evaluated in the laboratory-scale wastewater treatment model plant (M-WWTP), continuously supplied with the wastewater obtained from the full-scale WWTP. Number of fecal coliforms in raw (after mechanical treatment) and treated wastewater, as well as in aerobic chamber effluent was determined using selective medium. The selected strains were identified and examined for antibiotic resistance using Phoenix Automated Microbiology System (BD Biosciences, USA). The strains were identified as Escherichia coli (n=222), Klebsiella pneumoniae ssp. ozaenae (n=9), and Pantoea agglomerans (n=1). The isolate of P. agglomerans as well as 48% of E. coli isolates were sensitive to all antimicrobials tested. The most frequent resistance patterns were found for ampicillin: 100% of K. pneumoniae ssp. ozaenae and 41% of E. coli isolates. Among E. coli isolates 12% was regarded as multiple antimicrobial resistant (MAR). In the studied M-WWTP, the applied activated sludge processes reduced considerably the number of fecal coliforms, but increased the ratio of antimicrobial-resistant E. coli isolates to sensitive ones, especially among strains with MAR patterns.

  17. 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.

  18. Specific organization of Golgi apparatus in plant cells.

    Science.gov (United States)

    Vildanova, M S; Wang, W; Smirnova, E A

    2014-09-01

    Microtubules, actin filaments, and Golgi apparatus are connected both directly and indirectly, but it is manifested differently depending on the cell organization and specialization, and these connections are considered in many original studies and reviews. In this review we would like to discuss what underlies differences in the structural organization of the Golgi apparatus in animal and plant cells: specific features of the microtubule cytoskeleton organization, the use of different cytoskeleton components for Golgi apparatus movement and maintenance of its integrity, or specific features of synthetic and secretory processes. We suppose that a dispersed state of the Golgi apparatus in higher plant cells cannot be explained only by specific features of the microtubule system organization and by the absence of centrosome as an active center of their organization because the Golgi apparatus is organized similarly in the cells of other organisms that possess the centrosome and centrosomal microtubules. One of the key factors determining the Golgi apparatus state in plant cells is the functional uniformity or functional specialization of stacks. The functional specialization does not suggest the joining of the stacks to form a ribbon; therefore, the disperse state of the Golgi apparatus needs to be supported, but it also can exist "by default". We believe that the dispersed state of the Golgi apparatus in plants is supported, on one hand, by dynamic connections of the Golgi apparatus stacks with the actin filament system and, on the other hand, with the endoplasmic reticulum exit sites distributed throughout the endoplasmic reticulum.

  19. New aspects of gravity responses in plant cells.

    Science.gov (United States)

    Hoson, Takayuki; Soga, Kouichi

    2003-01-01

    Plants show two distinct responses to gravity: gravity-dependent morphogenesis (gravimorphogenesis) and gravity resistance. In gravitropism, a typical mechanism of gravimorphogenesis, gravity is utilized as a signal to establish an appropriate form. The response has been studied in a gravity-free environment, where plant seedlings were found to perform spontaneous morphogenesis, termed automorphogenesis. Automorphogenesis consists of a change in growth direction and spontaneous curvature in dorsiventral directions. The spontaneous curvature is caused by a difference in the capacity of the cell wall to expand between the dorsal and the ventral sides of organs, which originates from the inherent structural anisotropy. Gravity resistance is a response that enables the plant to develop against the gravitational force. To resist the force, the plant constructs a tough body by increasing the cell wall rigidity that suppresses growth. The mechanical properties of the cell wall are changed by modification of the cell wall metabolism and cell wall environment, especially pH. In gravitropism, gravity is perceived by amyloplasts in statocytes, whereas gravity resistance may be mediated by mechanoreceptors on the plasma membrane.

  20. The plant cell nucleus: a true arena for the fight between plants and pathogens.

    Science.gov (United States)

    Deslandes, Laurent; Rivas, Susana

    2011-01-01

    Communication between the cytoplasm and the nucleus is a fundamental feature shared by both plant and animal cells. Cellular factors involved in the transport of macromolecules through the nuclear envelope, including nucleoporins, importins and Ran-GTP related components, are conserved among a variety of eukaryotic systems. Interestingly, mutations in these nuclear components compromise resistance signalling, illustrating the importance of nucleocytoplasmic trafficking in plant innate immunity. Indeed, spatial restriction of defence regulators by the nuclear envelope and stimulus-induced nuclear translocation constitute an important level of defence-associated gene regulation in plants. A significant number of effectors from different microbial pathogens are targeted to the plant cell nucleus. In addition, key host factors, including resistance proteins, immunity components, transcription factors and transcriptional regulators shuttle between the cytoplasm and the nucleus, and their level of nuclear accumulation determines the output of the defence response, further confirming the crucial role played by the nucleus during the interaction between plants and pathogens. Here, we discuss recent findings that situate the nucleus at the frontline of the mutual recognition between plants and invading microbes.

  1. 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

  2. Cloning higher plants from aseptically cultured tissues and cells

    Science.gov (United States)

    Krikorian, A. D.

    1982-01-01

    A review of aseptic culture methods for higher plants is presented, which focuses on the existing problems that limit or prevent the full realization of cloning plants from free cells. It is shown that substantial progress in clonal multiplication has been made with explanted stem tips or lateral buds which can be stimulated to produce numerous precocious axillary branches. These branches can then be separated or subdivided and induced to root in order to yield populations of genetically and phenotypically uniorm plantlets. Similarly, undifferentiated calluses can sometimes be induced to form shoots and/or roots adventitiously. Although the cell culture techniques required to produce somatic embryos are presently rudimentary, steady advances are being made in learning how to stimulate formation of somatic or adventive embryos from totipotent cells grown in suspension cultures. It is concluded that many problems exist in the producing and growing of totipotent or morphogenetically competent cell suspensions, but the potential benefits are great.

  3. Plant cells use auxin efflux to explore geometry.

    Science.gov (United States)

    Zaban, Beatrix; Liu, Wenwen; Jiang, Xingyu; Nick, Peter

    2014-07-28

    Cell movement is the central mechanism for animal morphogenesis. Plant cell development rather relies on flexible alignment of cell axis adjusting cellular differentiation to directional cues. As central input, vectorial fields of mechanical stress and gradients of the phytohormone auxin have been discussed. In tissue contexts, mechanical and chemical signals will always act in concert; experimentally it is difficult to dissect their individual roles. We have designed a novel approach, based on cells, where directionality has been eliminated by removal of the cell wall. We impose a new axis using a microfluidic set-up to generate auxin gradients. Rectangular microvessels are integrated orthogonally with the gradient. Cells in these microvessels align their new axis with microvessel geometry before touching the wall. Auxin efflux is necessary for this touch-independent geometry exploration and we suggest a model, where auxin gradients can be used to align cell axis in tissues with minimized mechanical tensions.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Spatial pattern of cell geometry and cell-division orientation in zebrafish lens epithelium

    Directory of Open Access Journals (Sweden)

    Toshiaki Mochizuki

    2014-09-01

    Full Text Available Cell proliferation is a key regulator of tissue morphogenesis. We examined cell proliferation and cell division in zebrafish lens epithelium by visualizing cell-cycle phases and nuclear positions, using fluorescent-labeled geminin and histone proteins. Proliferation was low in the anterior region of lens epithelium and higher in the marginal zone anterior to the equator, suggesting that the proliferation zone, called the germinative zone, is formed in zebrafish lens. Interestingly, cell-division orientation was biased longitudinally in the anterior region, shifted from longitudinal to circumferential along the anterior–posterior axis of lens sphere, and was biased circumferentially in the peripheral region. These data suggest that cell-division orientation is spatially regulated in zebrafish lens epithelium. The Hertwig rule indicates that cells tend to divide along their long axes. Orientation of long axes and cell division were biased similarly in zebrafish lens epithelium, suggesting that cell geometry correlates with cell-division orientation. A cell adhesion molecule, E-cadherin, is expressed in lens epithelium. In a zebrafish e-cadherin mutant, the long axes and cell-division orientation were shifted more longitudinally. These data suggest that E-cadherin is required for the spatial pattern of cell geometry and cell-division orientation in zebrafish lens epithelium.

  9. 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...

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

    Directory of Open Access Journals (Sweden)

    Pedersen Henriette L

    2008-05-01

    Full Text Available Abstract Background Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally regulated. Xyloglucan is the major hemicellulose or cross-linking glycan of the primary cell walls of dicotyledons although little is known of its occurrence or functions in relation to cell development and cell wall microstructure. Results Using a neoglycoprotein approach, in which a XXXG heptasaccharide of tamarind seed xyloglucan was coupled to BSA to produce an immunogen, we have generated a rat monoclonal antibody (designated LM15 to the XXXG structural motif of xyloglucans. The specificity of LM15 has been confirmed by the analysis of LM15 binding using glycan microarrays and oligosaccharide hapten inhibition of binding studies. The use of LM15 for the analysis of xyloglucan in the cell walls of tamarind and nasturtium seeds, in which xyloglucan occurs as a storage polysaccharide, indicated that the LM15 xyloglucan epitope occurs throughout the thickened cell walls of the tamarind seed and in the outer regions, adjacent to middle lamellae, of the thickened cell walls of the nasturtium seed. Immunofluorescence analysis of LM15 binding to sections of tobacco and pea stem internodes indicated that the xyloglucan epitope was restricted to a few cell types in these organs. Enzymatic removal of pectic homogalacturonan from equivalent sections resulted in the abundant detection of distinct patterns of the LM15 xyloglucan epitope across these organs and a diversity of occurrences in relation to the cell wall microstructure of a range of cell types. Conclusion These observations support ideas that xyloglucan is associated with pectin in plant cell walls. They also indicate that documented patterns of cell wall epitopes in relation to cell

  11. Mechanisms of Organelle Inheritance in Dividing Plant Cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell generations. Although inheritance of organelles represents a fundamental component of the cell cycle, surprisingly little is known about the underlying mechanisms that facilitate unbiased organelle inheritance. Evidence from a select number of studies, however,indicates that ordered organelle inheritance strategies exist in dividing cells of higher plants. The basic requirement for unbiased organelle inheritance is the duplication of organelle volume and distribution of the resulting organelle populations in a manner that facilitates unbiased partitioning of the organelle population to each daughter cell. Often, partitioning strategies are specific to the organelle, being influenced by the functional requirements of the organelle and whether the cells are mitotically active or re-entering into the cell cycle. Organelle partitioning mechanisms frequently depend on interactions with either the actin or microtubule cytoskeleton. In this focused review, we attempt to summarize key findings regarding organelle partitioning strategies in dividing cells of higher plants. We particularly concentrate on the role of the cytoskeleton in mediating unbiased organelle partitioning.

  12. Plant recombinant erythropoietin attenuates inflammatory kidney cell injury.

    Science.gov (United States)

    Conley, Andrew J; Mohib, Kanishka; Jevnikar, Anthony M; Brandle, Jim E

    2009-02-01

    Human erythropoietin (EPO) is a pleiotropic cytokine with remarkable tissue-protective activities in addition to its well-established role in red blood cell production. Unfortunately, conventional mammalian cell cultures are unlikely to meet the anticipated market demands for recombinant EPO because of limited capacity and high production costs. Plant expression systems may address these limitations to enable practical, cost-effective delivery of EPO in tissue injury prevention therapeutics. In this study, we produced human EPO in tobacco and demonstrated that plant-derived EPO had tissue-protective activity. Our results indicated that targeting to the endoplasmic reticulum (ER) provided the highest accumulation levels of EPO, with a yield approaching 0.05% of total soluble protein in tobacco leaves. The codon optimization of the human EPO gene for plant expression had no clear advantage; furthermore, the human EPO signal peptide performed better than a tobacco signal peptide. In addition, we found that glycosylation was essential for the stability of plant recombinant EPO, whereas the presence of an elastin-like polypeptide fusion had a limited positive impact on the level of EPO accumulation. Confocal microscopy showed that apoplast and ER-targeted EPO were correctly localized, and N-glycan analysis demonstrated that complex plant glycans existed on apoplast-targeted EPO, but not on ER-targeted EPO. Importantly, plant-derived EPO had enhanced receptor-binding affinity and was able to protect kidney epithelial cells from cytokine-induced death in vitro. These findings demonstrate that tobacco plants may be an attractive alternative for the production of large amounts of biologically active EPO.

  13. Patterned Au/poly(dimethylsiloxane) substrate fabricated by chemical plating coupled with electrochemical etching for cell patterning.

    Science.gov (United States)

    Bai, Hai-Jing; Shao, Min-Ling; Gou, Hong-Lei; Xu, Jing-Juan; Chen, Hong-Yuan

    2009-09-01

    In this paper, we present a novel approach for preparing patterned Au/poly(dimethylsiloxane) (PDMS) substrate. Chemical gold plating instead of conventional metal evaporation or sputtering was introduced to achieve a homogeneous gold layer on native PDMS for the first time, which possesses low-cost and simple operation. An electrochemical oxidation reaction accompanied by the coordination of gold and chloride anion was then exploited to etch gold across the region covered by electrolyte. On the basis of such an electrochemical etching, heterogeneous Au/PDMS substrate which has a gold "island" pattern or PDMS dots pattern was fabricated. Hydrogen bubbles which were generated in the etching process due to water electrolysis were used to produce a safe region under the Pt auxiliary electrode. The safe region would protect gold film from etching and lead to the formation of the gold "island" pattern. In virtue of a PDMS stencil with holes array, gold could be etched from the exposed region and take on the PDMS dots pattern which was selected to for protein and cell patterning. This patterned Au/PDMS substrate is very convenient to construct cytophobic and cytophilic regions. Self-assembled surface modification of (1-mercaptoundec-11-yl)hexa(ethylene glycol) on gold and adsorption of fibronectin on PDMS are suitable for effective protein and cell patterning. This patterned Au/PDMS substrate would be a potentially versatile platform for fabricating biosensing arrays.

  14. 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.

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

    NARCIS (Netherlands)

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

    2001-01-01

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

  16. Fluorescence Correlation Spectroscopy Applied to Living Plant Cells

    NARCIS (Netherlands)

    Hink, M.A.

    2002-01-01

    Keywords: Fluorescence correlation spectroscopy, photon counting histogram, intracellular, plant, AtSERK1In order to survive organisms have to be capable to adjust theirselves to changes in the environment. Cells, the building blocks of an organism react to these

  17. Measuring the Mechanical Properties of Plant Cell Walls

    Directory of Open Access Journals (Sweden)

    Hannes Vogler

    2015-03-01

    Full Text Available The size, shape and stability of a plant depend on the flexibility and integrity of its cell walls, which, at the same time, need to allow cell expansion for growth, while maintaining mechanical stability. Biomechanical studies largely vanished from the focus of plant science with the rapid progress of genetics and molecular biology since the mid-twentieth century. However, the development of more sensitive measurement tools renewed the interest in plant biomechanics in recent years, not only to understand the fundamental concepts of growth and morphogenesis, but also with regard to economically important areas in agriculture, forestry and the paper industry. Recent advances have clearly demonstrated that mechanical forces play a crucial role in cell and organ morphogenesis, which ultimately define plant morphology. In this article, we will briefly review the available methods to determine the mechanical properties of cell walls, such as atomic force microscopy (AFM and microindentation assays, and discuss their advantages and disadvantages. But we will focus on a novel methodological approach, called cellular force microscopy (CFM, and its automated successor, real-time CFM (RT-CFM.

  18. 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.

  19. Contrasting water use pattern of introduced and native plants in an alpine desert ecosystem, Northeast Qinghai–Tibet Plateau, China

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huawu, E-mail: wuhuawu416@163.com [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875 (China); College of Resources Science and Technology, Beijing Normal University, Beijing 100875 (China); Li, Xiao-Yan, E-mail: xyli@bnu.edu.cn [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875 (China); College of Resources Science and Technology, Beijing Normal University, Beijing 100875 (China); Jiang, Zhiyun; Chen, Huiying; Zhang, Cicheng; Xiao, Xiong [College of Resources Science and Technology, Beijing Normal University, Beijing 100875 (China)

    2016-01-15

    Plant water use patterns reflect the complex interactions between different functional types and environmental conditions in water-limited ecosystems. However, the mechanisms underlying the water use patterns of plants in the alpine desert of the Qinghai–Tibet Plateau remain poorly understood. This study investigated seasonal variations in the water sources of herbs (Carex moorcroftii, Astragalus adsurgens) and shrubs (Artemisia oxycephala, Hippophae rhamnoides) using stable oxygen-18 isotope methods. The results indicated that the native herbs (C. moorcroftii, A. adsurgens) and one of the shrubs (A. oxycephala) mainly relied on water from the shallow layer (0–30 cm) throughout the growing season, while the introduced shrub (H. rhamnoides) showed plasticity in switching between water from shallow and deep soil layers depending on soil water availability. All studied plants primarily depended on water from shallow soil layers early in the season. The differences of water use patterns between the introduced and native plants are closely linked with the range of active root zones when competing for water. Our findings will facilitate the mechanistic understanding of plant–soil–water relations in alpine desert ecosystems and provide information for screening introduced species for sand fixation. - Highlights: • Stable oxygen-18 in soil water experienced great evaporation enrichment. • H. rhamnoides experiences a flexible plasticity to switch between shallow and deep soil water. • Native plants mostly relied on shallow and middle soil water. • Water-use patterns by introduced-native plants are controlled by root characteristics.

  20. Weed Control and Corn (Zea mays Response to Planting Pattern and Herbicide Program with High Seeding Rates in North Carolina

    Directory of Open Access Journals (Sweden)

    Mitchell K. Williams

    2014-01-01

    Full Text Available Effective weed control in corn (Zea mays L. is important to optimize yield. Concern over environmental impact of atrazine and selection for glyphosate resistance has increased the need to develop alternative strategies that use herbicides other than atrazine and glyphosate and appropriate cultural practices to control weeds. Research was conducted during 2011 and 2012 to determine weed and corn response to herbicide programs containing dicamba, glufosinate, and glyphosate applied postemergence alone or with atrazine in single- and twin-row planting patterns. Planting pattern had no effect on common ragweed (Ambrosia artemisiifolia L. and Texas panicum (Panicum texanum L. population and did not interact with herbicide program. Effective weed control hastened maturity in some but not all instances. Under weed-free conditions, corn grain yield was higher in 5 of 7 trials when planted in twin rows versus single rows at equivalent corn populations (141,000 plants ha−1. These results suggest that while planting pattern may not impact weed control dramatically, planting corn in twin rows may be an effective alternative to single-row planting patterns because of increased yield under high corn populations.

  1. 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

    , and the Tibetan Plateau, perhaps reflecting their special geological features and history. Nevertheless, partial regression indicated that historical effects were less important relative to contemporary environment. In conclusion, contemporary environment (notably climate) determines the general trend in woody...... between these regions, indicating significant deviation from the predicted species richness based on contemporary environment. Additionally, species richness of a given biogeographical region deviated substantially from the predictions of species richness-environment models developed for the remaining...... 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...

  2. Patterning of Endothelial Cells and Mesenchymal Stem Cells by Laser-Assisted Bioprinting to Study Cell Migration

    Directory of Open Access Journals (Sweden)

    Jean-Michel Bourget

    2016-01-01

    Full Text Available Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro. Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs. The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors.

  3. Patterning of Endothelial Cells and Mesenchymal Stem Cells by Laser-Assisted Bioprinting to Study Cell Migration

    Science.gov (United States)

    Medina, Manuela; Rémy, Murielle; Thébaud, Noélie Brunehilde; Bareille, Reine; Chassande, Olivier; Amédée, Joëlle; Catros, Sylvain

    2016-01-01

    Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro. Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs). The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors. PMID:27833916

  4. Cytoplasmic streaming in plant cells emerges naturally by microfilament self-organization.

    Science.gov (United States)

    Woodhouse, Francis G; Goldstein, Raymond E

    2013-08-27

    Many cells exhibit large-scale active circulation of their entire fluid contents, a process termed cytoplasmic streaming. This phenomenon is particularly prevalent in plant cells, often presenting strikingly regimented flow patterns. The driving mechanism in such cells is known: myosin-coated organelles entrain cytoplasm as they process along actin filament bundles fixed at the periphery. Still unknown, however, is the developmental process that constructs the well-ordered actin configurations required for coherent cell-scale flow. Previous experimental works on streaming regeneration in cells of Characean algae, whose longitudinal flow is perhaps the most regimented of all, hint at an autonomous process of microfilament self-organization driving the formation of streaming patterns during morphogenesis. Working from first principles, we propose a robust model of streaming emergence that combines motor dynamics with both microscopic and macroscopic hydrodynamics to explain how several independent processes, each ineffectual on its own, can reinforce to ultimately develop the patterns of streaming observed in the Characeae and other streaming species.

  5. Patterns of plant diversity in seven temperate forest types of Western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Javid Ahmad Dar

    2016-09-01

    Full Text Available Plant biodiversity patterns were analyzed in seven temperate forest types [Populus deltoides (PD, Juglans regia, Cedrus deodara, Pinus wallichiana, mixed coniferous, Abies pindrow (AP and Betula utilis (BU] of Kashmir Himalaya. A total of 177 plant species (158 genera, 66 families were recorded. Most of the species are herbs (82.5%, while shrubs account for 9.6% and trees represent 7.9%. Species richness ranged from 24 (PD to 96 (AP. Shannon, Simpson, and Fisher α indices varied: 0.17–1.06, 0.46–1.22, and 2.01–2.82 for trees; 0.36–0.94, 0.43–0.75, and 0.08–0.35 for shrubs; and 0.35–1.41, 0.27–0.95, and 5.61–39.98 for herbs, respectively. A total of five species were endemic. The total stems and basal area of trees were 35,794 stems (stand mean 330 stems/ha and 481.1 m2 (stand mean 40.2 m2/ha, respectively. The mean density and basal area ranged from 103 stems/ha (BU to 1,201 stems/ha (PD, and from 19.4 m2/ha (BU to 51.9 m2/ha (AP, respectively. Tree density decreased with increase in diameter class. A positive relationship was obtained between elevation and species richness and between elevation and evenness (R2 = 0.37 and 0.19, respectively. Tree and shrub communities were homogenous in nature across the seven forest types, while herbs showed heterogeneous distribution pattern.

  6. 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.

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

    DEFF Research Database (Denmark)

    Liesche, Johannes; Schulz, Alexander

    2015-01-01

    by 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...

  8. Molecular mechanisms of cholangiocarcinoma cell inhibition by medicinal plants

    Science.gov (United States)

    Leelawat, Surang; Leelawat, Kawin

    2017-01-01

    Cholangiocarcinoma (CCA) is one of the most common causes of cancer-associated mortality in Thailand. Certain phytochemicals have been demonstrated to modulate apoptotic signaling pathways, which may be targeted for the prevention and treatment of cancer. Therefore, the aim of the present study was to investigate the effect of specific medicinal plants on the inhibition of CCA cell proliferation, and to identify the molecular mechanisms underlying this. A WST-1 cell proliferation assay was performed using an RMCCA1 cell line, and apoptotic signaling pathways were also investigated using a PathScan Stress and Apoptosis Signaling Antibody Array Kit. The cell proliferation assay indicated that extracts from the Phyllanthus emblica fruit pulp (PEf), Phyllanthus emblica seed (PEs), Terminalia chebula fruit pulp (TCf), Terminalia chebula seed (TCs), Areca catechu seed (ACs), Curcuma longa (CL) and Moringa oleifera seed (MOs) exerted anti-proliferative activity in RMCCA1 cells. In addition, the PathScan assay revealed that certain pro-apoptotic molecules, including caspase-3, poly (ADP-ribose) polymerase, checkpoint kinase 2 and tumor protein 53, exhibited increased activity in RMCCA1 cells treated with the aforementioned selected plant extracts, with the exception of PEf. The mitogen-activated protein kinase (MAPK) pathways (including ERK1/2 and p38 MAPK) expression level was significantly increased in RMCCA1 cells pre-treated with extracts of PEs, TCf, CL and MOs. The activation of protein kinase B (Akt) was significantly demonstrated in RMCCA1 cells pre-treated with extracts of TCf, ACs and MOs. In summary, the present study demonstrated that extracts of PEs, TCf, TCs, ACs, CL and MOs exhibited anti-proliferative effects in CCA cells by inducing pro-apoptotic signals and modulating signal transduction molecules. Further studies in vivo are required to demonstrate the potential applications of specific plant extracts for the treatment of human cancer.

  9. Introducing the Cell Concept with Both Animal and Plant Cells: A Historical and Didactic Approach

    Science.gov (United States)

    Clement, Pierre

    2007-01-01

    In France, as well as in several other countries, the cell concept is introduced at school by two juxtaposed drawings, a plant cell and an animal cell. After indicating the didactic obstacles associated with this presentation, this paper focuses on the reasons underlying the persistence of these two prototypes, through three complementary…

  10. 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

    2016-08-23

    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.

  11. Micrasterias as a Model System in Plant Cell Biology

    Science.gov (United States)

    Lütz-Meindl, Ursula

    2016-01-01

    The unicellular freshwater alga Micrasterias denticulata is an exceptional organism due to its complex star-shaped, highly symmetric morphology and has thus attracted the interest of researchers for many decades. As a member of the Streptophyta, Micrasterias is not only genetically closely related to higher land plants but shares common features with them in many physiological and cell biological aspects. These facts, together with its considerable cell size of about 200 μm, its modest cultivation conditions and the uncomplicated accessibility particularly to any microscopic techniques, make Micrasterias a very well suited cell biological plant model system. The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction. It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation. Stress induced organelle degradation, autophagy, adaption and detoxification mechanisms have moved in the center of interest and have been investigated with modern microscopic techniques such as 3-D- and analytical electron microscopy as well as with biochemical, physiological and molecular approaches. This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells. PMID:27462330

  12. 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.

  13. Micrasterias as a model system in plant cell biology

    Directory of Open Access Journals (Sweden)

    Ursula Luetz-Meindl

    2016-07-01

    Full Text Available The unicellular freshwater alga Micrasterias denticulata is an exceptional organism due to its extraordinary star-shaped, highly symmetric morphology and has thus attracted the interest of researchers for many decades. As a member of the Streptophyta, Micrasterias is not only genetically closely related to higher land plants but shares common features with them in many physiological and cell biological aspects. These facts, together with its considerable cell size of about 200 µm, its modest cultivation conditions and the uncomplicated accessibility particularly to any microscopic techniques, make Micrasterias a very well suited cell biological plant model system. The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction. It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation. Stress induced organelle degradation, autophagy, adaption and detoxification mechanisms have moved in the center of interest and have been investigated with modern microscopic techniques such as 3-D- and analytical electron microscopy as well as with biochemical, physiological and molecular approaches. This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.

  14. Putting On The Breaks: Regulating Organelle Movements in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Julianna K.Vick; Andreas Nebenführ

    2012-01-01

    A striking characteristic of plant cells is that their organelles can move rapidly through the cell.This movement,commonly referred to as cytoplasmic streaming,has been observed for over 200 years,but we are only now beginning to decipher the mechanisms responsible for it.The identification of the myosin motor proteins responsible for these movements allows us to probe the regulatory events that coordinate organelle displacement with normal cell physiology.This review will highlight several recent developments that have provided new insight into the regulation of organelle movement,both at the cellular level and at the molecular level.

  15. 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...

  16. Homotypic fusion of endoplasmic reticulum membranes in plant cells

    Directory of Open Access Journals (Sweden)

    Junjie eHu

    2013-12-01

    Full Text Available The endoplasmic reticulum (ER is a membrane-bounded organelle whose membrane comprises a network of tubules and sheets. The formation of these characteristic shapes and maintenance of their continuity through homotypic membrane fusion appears to be critical for the proper functioning of the ER. The atlastins (ATLs, a family of ER-localized dynamin-like GTPases, have been identified as fusogens of the ER membranes in metazoans. Mutations of the ATL proteins in mammalian cells cause morphological defects in the ER, and purified Drosophila ATL mediates membrane fusion in vitro. Plant cells do not possess ATL, but a family of similar GTPases, named root hair defective 3 (RHD3, are likely the functional orthologs of ATLs. In this review, we summarize recent advances in our understanding of how RHD3 proteins play a role in homotypic ER fusion. We also discuss the possible physiological significance of forming a tubular ER network in plant cells.

  17. General patterns of acclimation of leaf respiration to elevated temperatures across biomes and plant types.

    Science.gov (United States)

    Slot, Martijn; Kitajima, Kaoru

    2015-03-01

    Respiration is instrumental for survival and growth of plants, but increasing costs of maintenance processes with warming have the potential to change the balance between photosynthetic carbon uptake and respiratory carbon release from leaves. Climate warming may cause substantial increases of leaf respiratory carbon fluxes, which would further impact the carbon balance of terrestrial vegetation. However, downregulation of respiratory physiology via thermal acclimation may mitigate this impact. We have conducted a meta-analysis with data collected from 43 independent studies to assess quantitatively the thermal acclimation capacity of leaf dark respiration to warming of terrestrial plant species from across the globe. In total, 282 temperature contrasts were included in the meta-analysis, representing 103 species of forbs, graminoids, shrubs, trees and lianas native to arctic, boreal, temperate and tropical ecosystems. Acclimation to warming was found to decrease respiration at a set temperature in the majority of the observations, regardless of the biome of origin and growth form, but respiration was not completely homeostatic across temperatures in the majority of cases. Leaves that developed at a new temperature had a greater capacity for acclimation than those transferred to a new temperature. We conclude that leaf respiration of most terrestrial plants can acclimate to gradual warming, potentially reducing the magnitude of the positive feedback between climate and the carbon cycle in a warming world. More empirical data are, however, needed to improve our understanding of interspecific variation in thermal acclimation capacity, and to better predict patterns in respiratory carbon fluxes both within and across biomes in the face of ongoing global warming.

  18. 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.

  19. 1000kW phosphoric acid fuel cell power plant. Outline of the plant

    Energy Technology Data Exchange (ETDEWEB)

    Shinobe, Kenji; Suzuki, Kazuo; Kaneko, Hideo

    1988-02-10

    The outline of the 1000KW phosphoric acid fuel cell power plant, developed as part of the Moonlight plan, was described. The plant was composed of 4 stacks of 260KW DC output. They were devided into two train with 680V and 765A. The generation efficiency of the plant was 40% and more. Steam reforming of natural gas was used. As the fuel, fuel cell exhaust gas was used in composition with the natural gas. The DC-AC inverter had an efficiency of 96%. The capacity of hot water generator and demineralized water plant for cell cooling were 2t/h and 1.6t/h, respectively, and air-system was incorporated. In September of 1987, the plant has succeeded in 1000KW power generation, and put in operation now. Under the 100% loaded condition, each cell had a voltage of 0.7V with little variation, and the current was 200mA/cm/sup 2/. No problems were found in cooling conditions and in the control of interpole differential pressure. The reformer has been operated for 1200h scince its commisioning, and had experiences of 100 times on start up-shut down operations, the reformer also indicated good performances in the gas compositions. The starting time of 8h and the load follow-up rate 10%/min remain as the subjects for shortening. DC-AC conversion was good. The concentration of NOx and the noise level satisfied the target values. (12 figs, 1 tab)

  20. Production of therapeutic proteins through plant tissue and cell culture

    Directory of Open Access Journals (Sweden)

    Reza S. Gharelo

    2016-04-01

    Full Text Available Nowadays, pharmaceutical recombinant protein is increasingly used in treatment of many diseases such as hepatitis, anemia, diabetes and cancer. Different protein expression systems have been used for the expression of recombinant proteins in which each of them face obstacles that make utilizing them as comprehensive expression system in order to express wide variety of proteins difficult. Plant cell as a eukaryotic expression system have many advantages compared to other hosts. They are very "safe" and significantly decrease concerns about the contamination of recombinant proteins with human pathogens. In addition to this, plants as eukaryotic expression system perform proper post-translational modification, in case of eukaryotic proteins, and appropriate folding resulting in right function in biological environments. Therefore, the production of pharmaceutical protein through plant cells can be absolutely promising approach. In this review, the production of pharmaceutical protein in plant cells, advantages and disadvantages, offered methods and techniques for developing recombinant protein yields, and affective factors on the whole process of pharmaceutical protein expression in the molecular level will be reviewed.

  1. 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

  2. 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.

  3. Vacuum-assisted fluid flow in microchannels to pattern substrates and cells.

    Science.gov (United States)

    Shrirao, Anil B; Kung, Frank H; Yip, Derek; Cho, Cheul H; Townes-Anderson, Ellen

    2014-09-01

    Substrate and cell patterning are widely used techniques in cell biology to study cell-to-cell and cell-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This paper describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. Our method builds upon a previous vacuum-assisted method used for micromolding (Jeon et al 1999 Adv. Mater 11 946) and successfully patterned collagen-I, fibronectin and Sal-1 substrates on glass and polystyrene surfaces, filling microchannels with lengths up to 120 mm and covering areas up to 13 × 10 mm(2). Vacuum-patterned substrates were subsequently used to culture mammalian PC12 and fibroblast cells and amphibian neurons. Cells were also patterned directly by injecting cell suspensions into microchannels using vacuum. Fibroblast and neuronal cells patterned using vacuum showed normal growth and minimal cell death indicating no adverse effects of vacuum on cells. Our method fills reversibly sealed PDMS microchannels. This enables the user to remove the PDMS microchannel cast and access the patterned biomaterial or cells for further experimental purposes. Overall, this is a straightforward technique that has broad applicability for cell biology.

  4. Can plant oncogenes inhibit programmed cell death? The rolB oncogene reduces apoptosis-like symptoms in transformed plant cells.

    Science.gov (United States)

    Gorpenchenko, Tatiana Y; Aminin, Dmitry L; Vereshchagina, Yuliya V; Shkryl, Yuri N; Veremeichik, Galina N; Tchernoded, Galina K; Bulgakov, Victor P

    2012-09-01

    The rolB oncogene was previously identified as an important player in ROS metabolism in transformed plant cells. Numerous reports indicate a crucial role for animal oncogenes in apoptotic cell death. Whether plant oncogenes such as rolB can induce programmed cell death (PCD) in transformed plant cells is of particular importance. In this investigation, we used a single-cell assay based on confocal microscopy and fluorescent dyes capable of discriminating between apoptotic and necrotic cells. Our results indicate that the expression of rolB in plant cells was sufficient to decrease the proportion of apoptotic cells in steady-state conditions and diminish the rate of apoptotic cells during induced PCD. These data suggest that plant oncogenes, like animal oncogenes, may be involved in the processes mediating PCD.

  5. Polymorphism and methylation patterns in Agave tequilana Weber var. 'Azul' plants propagated asexually by three different methods.

    Science.gov (United States)

    Díaz-Martínez, Miriam; Nava-Cedillo, Alejandro; Guzmán-López, José Alfredo; Escobar-Guzmán, Rocío; Simpson, June

    2012-04-01

    Genetic variation in three forms of asexually propagated Agave tequilana Weber var. 'Azul' plants namely offsets, bulbils and in vitro cultured individuals was studied by AFLP analysis. Low levels of variation were observed between mother plants and offsets and a higher level between mother plant and bulbils. Families obtained from commercial plantations showed lower levels of variation in comparison to families grown as ornamentals. No variation was observed between the original explant and four generations of in vitro cultured plants. Epigenetic variation was also studied by analyzing changes in methylation patterns between mother plants and offspring in each form of asexual reproduction. Offsets and bulbils showed an overall decrease in methylation whereas in vitro cultured plants showed patterns specific to each generation: Generations 1 and 4 showed overall demethylation whereas Generations 2 and 3 showed increased methylation. Analysis of ESTs associated with transposable elements revealed higher proportions of ESTs from Ty1-copia-like, Gypsy and CACTA transposable elements in cDNA libraries obtained from pluripotent tissue suggesting a possible correlation between methylation patterns, expression of transposable element associated genes and somaclonal variation.

  6. Hydrogen peroxide homeostasis and signaling in plant cells

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid).Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments.H2O2 can modulate the activities of many components in signaling, such as protein phosphatases,protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.

  7. Alterations in the growth and adhesion pattern of Vero cells induced by nutritional stress conditions.

    Science.gov (United States)

    Genari, S C; Gomes, L; Wada, M L

    1998-01-01

    The pattern of growth, adhesion and protein synthesis in Vero cells submitted to nutritional stress conditions was investigated. The control cells presented a characteristic pattern, with monolayer growth, while the stressed cells presented multilayered growth, with aggregate or spheroid formation which detached on the flask surface and continued their growth in another region. In the soft agar assay, with reduced amount of nutrients, only the stressed cells presented growth, indicating physical and nutritional independence. A 44-kDa protein was observed in stressed cells and was absent in non-stressed cells. The adhesion index and fibronectin synthesis and distribution were altered in stressed cells. After confluence, control cells presented fibronectin accumulation in lateral cell-cell contact regions, while this fibronectin accumulation pattern was not observed in stressed cells. These alterations may be responsible for the multilayered growth and decreased adhesion index observed in stressed cells which were transformed by nutritional stress conditions.

  8. Manual of phosphoric acid fuel cell power plant optimization model and computer program

    Science.gov (United States)

    Lu, C. Y.; Alkasab, K. A.

    1984-01-01

    An optimized cost and performance model for a phosphoric acid fuel cell power plant system was derived and developed into a modular FORTRAN computer code. Cost, energy, mass, and electrochemical analyses were combined to develop a mathematical model for optimizing the steam to methane ratio in the reformer, hydrogen utilization in the PAFC plates per stack. The nonlinear programming code, COMPUTE, was used to solve this model, in which the method of mixed penalty function combined with Hooke and Jeeves pattern search was chosen to evaluate this specific optimization problem.

  9. Cell physiology of plants growing in cold environments.

    Science.gov (United States)

    Lütz, Cornelius

    2010-08-01

    The life of plants growing in cold extreme environments has been well investigated in terms of morphological, anatomical, and ecophysiological adaptations. In contrast, long-term cellular or metabolic studies have been performed by only a few groups. Moreover, a number of single reports exist, which often represent just a glimpse of plant behavior. The review draws together the literature which has focused on tissue and cellular adaptations mainly to low temperatures and high light. Most studies have been done with European alpine plants; comparably well studied are only two phanerogams found in the coastal Antarctic. Plant adaptation in northern polar regions has always been of interest in terms of ecophysiology and plant propagation, but nowadays, this interest extends to the effects of global warming. More recently, metabolic and cellular investigations have included cold and UV resistance mechanisms. Low-temperature stress resistance in plants from cold environments reflects the climate conditions at the growth sites. It is now a matter of molecular analyses to find the induced genes and their products such as chaperones or dehydrins responsible for this resistance. Development of plants under snow or pollen tube growth at 0 degrees C shows that cell biology is needed to explain the stability and function of the cytoskeleton. Many results in this field are based on laboratory studies, but several publications show that it is not difficult to study cellular mechanisms with the plants adapted to a natural stress. Studies on high light and UV loads may be split in two parts. Many reports describe natural UV as harmful for the plants, but these studies were mainly conducted by shielding off natural UV (as controls). Other experiments apply additional UV in the field and have had practically no negative impact on metabolism. The latter group is supported by the observations that green overwintering plants increase their flavonoids under snow even in the absence of

  10. A role for katanin in plant cell division: microtubule organization in dividing root cells of fra2 and lue1Arabidopsis thaliana mutants.

    Science.gov (United States)

    Panteris, Emmanuel; Adamakis, Ioannis-Dimosthenis S; Voulgari, Georgia; Papadopoulou, Galini

    2011-07-01

    Severing of microtubules by katanin has proven to be crucial for cortical microtubule organization in elongating and differentiating plant cells. On the contrary, katanin is currently not considered essential during cell division in plants as it is in animals. However, defects in cell patterning have been observed in katanin mutants, implying a role for it in dividing plant cells. Therefore, microtubule organization was studied in detail by immunofluorescence in dividing root cells of fra2 and lue1 katanin mutants of Arabidopsis thaliana. In both, early preprophase bands consisted of poorly aligned microtubules, prophase spindles were multipolar, and the microtubules of expanding phragmoplasts were elongated, bended toward and connected to the surface of daughter nuclei. Accordingly, severing by katanin seems to be necessary for the proper organization of these microtubule arrays. In both fra2 and lue1, metaphase/anaphase spindles and initiating phragmoplasts exhibited typical organization. However, they were obliquely oriented more frequently than in the wild type. It is proposed that this oblique orientation may be due to prophase spindle multipolarity and results in a failure of the cell plate to follow the predetermined division plane, during cytokinesis, producing oblique cell walls in the roots of both mutants. It is therefore concluded that, like in animal cells, katanin is important for plant cell division, influencing the organization of several microtubule arrays. Moreover, failure in microtubule severing indirectly affects the orientation of the division plane.

  11. Secondary Metabolite Localization by Autofluorescence in Living Plant Cells

    Directory of Open Access Journals (Sweden)

    Pascale Talamond

    2015-03-01

    Full Text Available Autofluorescent molecules are abundant in plant cells and spectral images offer means for analyzing their spectra, yielding information on their accumulation and function. Based on their fluorescence characteristics, an imaging approach using multiphoton microscopy was designed to assess localization of the endogenous fluorophores in living plant cells. This method, which requires no previous treatment, provides an effective experimental tool for discriminating between multiple naturally-occurring fluorophores in living-tissues. Combined with advanced Linear Unmixing, the spectral analysis extends the possibilities and enables the simultaneous detection of fluorescent molecules reliably separating overlapping emission spectra. However, as with any technology, the possibility for artifactual results does exist. This methodological article presents an overview of the applications of tissular and intra-cellular localization of these intrinsic fluorophores in leaves and fruits (here for coffee and vanilla. This method will provide new opportunities for studying cellular environments and the behavior of endogenous fluorophores in the intracellular environment.

  12. Plant phosphoglycerolipids: the gatekeepers of vascular cell differentiation

    Directory of Open Access Journals (Sweden)

    Bojan eGujas

    2016-02-01

    Full Text Available In higher plants, the plant vascular system has evolved as an inter-organ communication network essential to deliver a wide range of signaling factors among distantly separated organs. To become conductive elements, phloem and xylem cells undergo a drastic differentiation program that involves the degradation of the majority of their organelles. While the molecular mechanisms regulating such complex process remain poorly understood, it is nowadays clear that phosphoglycerolipids display a pivotal role in the regulation of vascular formation. In animal cells, this class of lipids is known to mediate acute responses as signal transducers and also act as constitutive signals that help defining organelle identity. Their rapid turnover, asymmetrical distribution across subcellular compartments as well as their ability to rearrange cytoskeleton fibers make phosphoglycerolipids excellent candidates to regulate complex morphogenetic processes such as vascular differentiation. Therefore, in this review we aim to summarize, emphasize and connect our current understanding about the involvement of phosphoglycerolipids in phloem and xylem differentiation.

  13. Plant cell walls: New insights from ancient species

    DEFF Research Database (Denmark)

    Sørensen, Iben; Willats, William George Tycho

    2008-01-01

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

  14. Gene Delivery into Plant Cells for Recombinant Protein Production

    OpenAIRE

    Qiang Chen; Huafang Lai

    2015-01-01

    Recombinant proteins are primarily produced from cultures of mammalian, insect, and bacteria cells. In recent years, the development of deconstructed virus-based vectors has allowed plants to become a viable platform for recombinant protein production, with advantages in versatility, speed, cost, scalability, and safety over the current production paradigms. In this paper, we review the recent progress in the methodology of agroinfiltration, a solution to overcome the challenge of transgene d...

  15. Vacuolar processing enzyme in plant programmed cell death

    Directory of Open Access Journals (Sweden)

    Noriyuki eHatsugai

    2015-04-01

    Full Text Available Vacuolar processing enzyme (VPE is a cysteine proteinase originally identified as the proteinase responsible for the maturation and activation of vacuolar proteins in plants, and it is known to be an orthologue of animal asparaginyl endopeptidase (AEP/VPE/legumain. VPE has been shown to exhibit enzymatic properties similar to that of caspase 1, which is a cysteine protease that mediates the programmed cell death (PCD pathway in animals. Although there is limited sequence identity between VPE and caspase 1, their predicted three-dimensional structures revealed that the essential amino-acid residues for these enzymes form similar pockets for the substrate peptide YVAD. In contrast to the cytosolic localization of caspases, VPE is localized in vacuoles. VPE provokes vacuolar rupture, initiating the proteolytic cascade leading to PCD in the plant immune response. It has become apparent that the VPE-dependent PCD pathway is involved not only in the immune response, but also in the responses to a variety of stress inducers and in the development of various tissues. This review summarizes the current knowledge on the contribution of VPE to plant PCD and its role in vacuole-mediated cell death, and it also compares VPE with the animal cell death executor caspase 1.

  16. 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.

  17. 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.

  18. 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.

  19. Comparative analysis of cells and proteins of pumpkin plants for the control of fruit size.

    Science.gov (United States)

    Nakata, Yumiko; Taniguchi, Go; Takazaki, Shinya; Oda-Ueda, Naoko; Miyahara, Kohji; Ohshima, Yasumi

    2012-09-01

    Common pumpkin plants (Cucurbita maxima) produce fruits of 1-2 kg size on the average, while special varieties of the same species called Atlantic Giant are known to produce a huge fruit up to several hundred kilograms. As an approach to determine the factors controlling the fruit size in C. maxima, we cultivated both AG and control common plants, and found that both the cell number and cell sizes were increased in a large fruit while DNA content of the cell did not change significantly. We also compared protein patterns in the leaves, stems, ripe and young fruits by two-dimensional (2D) gel electrophoresis, and identified those differentially expressed between them with mass spectroscopy. Based on these results, we suggest that factors in photosynthesis such as ribulose-bisphosphate carboxylase, glycolysis pathway enzymes, heat-shock proteins and ATP synthase play positive or negative roles in the growth of a pumpkin fruit. These results provide a step toward the development of plant biotechnology to control fruit size in the future.

  20. 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

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

    Directory of Open Access Journals (Sweden)

    Firas eBou Daher

    2015-07-01

    Full Text Available Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbours, 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.

  2. Contrasting water use pattern of introduced and native plants in an alpine desert ecosystem, Northeast Qinghai-Tibet Plateau, China.

    Science.gov (United States)

    Wu, Huawu; Li, Xiao-Yan; Jiang, Zhiyun; Chen, Huiying; Zhang, Cicheng; Xiao, Xiong

    2016-01-15

    Plant water use patterns reflect the complex interactions between different functional types and environmental conditions in water-limited ecosystems. However, the mechanisms underlying the water use patterns of plants in the alpine desert of the Qinghai-Tibet Plateau remain poorly understood. This study investigated seasonal variations in the water sources of herbs (Carex moorcroftii, Astragalus adsurgens) and shrubs (Artemisia oxycephala, Hippophae rhamnoides) using stable oxygen-18 isotope methods. The results indicated that the native herbs (C. moorcroftii, A. adsurgens) and one of the shrubs (A. oxycephala) mainly relied on water from the shallow layer (0-30 cm) throughout the growing season, while the introduced shrub (H. rhamnoides) showed plasticity in switching between water from shallow and deep soil layers depending on soil water availability. All studied plants primarily depended on water from shallow soil layers early in the season. The differences of water use patterns between the introduced and native plants are closely linked with the range of active root zones when competing for water. Our findings will facilitate the mechanistic understanding of plant-soil-water relations in alpine desert ecosystems and provide information for screening introduced species for sand fixation.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. A mixture of peptides and sugars derived from plant cell walls increases plant defense responses to stress and attenuates ageing-associated molecular changes in cultured skin cells.

    Science.gov (United States)

    Apone, Fabio; Tito, Annalisa; Carola, Antonietta; Arciello, Stefania; Tortora, Assunta; Filippini, Lucio; Monoli, Irene; Cucchiara, Mirna; Gibertoni, Simone; Chrispeels, Maarten J; Colucci, Gabriella

    2010-02-15

    Small peptides and aminoacid derivatives have been extensively studied for their effect of inducing plant defense responses, and thus increasing plant tolerance to a wide range of abiotic stresses. Similarly to plants, these compounds can activate different signaling pathways in mammalian skin cells as well, leading to the up-regulation of anti-aging specific genes. This suggests the existence of analogous defense response mechanisms, well conserved both in plants and animal cells. In this article, we describe the preparation of a new mixture of peptides and sugars derived from the chemical and enzymatic digestion of plant cell wall glycoproteins. We investigate the multiple roles of this product as potential "biostimulator" to protect plants from abiotic stresses, and also as potential cosmeceutical. In particular, the molecular effects of the peptide/sugar mixture of inducing plant defense responsive genes and protecting cultured skin cells from oxidative burst damages were deeply evaluated.

  9. Climate vs. topography – spatial patterns of plant species diversity and endemism on a high-elevation island

    DEFF Research Database (Denmark)

    Irl, Severin David Howard; Harter, David E. V.; Steinbauer, Manuel;

    2015-01-01

    variables (esp. elevation/temperature and rainfall seasonality) explain endemicity. Spatial patterns of species richness, endemic richness and endemicity were in part geographically decoupled from each other. Synthesis. We identified several topography-dependent processes ranging from evolutionary processes......Climate and topography are among the most fundamental drivers of plant diversity. Here, we assessed the importance of climate and topography in explaining diversity patterns of species richness, endemic richness and endemicity on the landscape scale of an oceanic island and evaluated...... the independent contribution of climatic and topographic variables to spatial diversity patterns. We constructed a presence/absence matrix of perennial endemic and native vascular plant species (including subspecies) in 890 plots on the environmentally very heterogeneous island of La Palma, Canary Islands...

  10. 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.

  11. 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.

  12. 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.

  13. Plant cell nucleolus as a hot spot for iron.

    Science.gov (United States)

    Roschzttardtz, Hannetz; Grillet, Louis; Isaure, Marie-Pierre; Conéjéro, Geneviève; Ortega, Richard; Curie, Catherine; Mari, Stéphane

    2011-08-12

    Many central metabolic processes require iron as a cofactor and take place in specific subcellular compartments such as the mitochondrion or the chloroplast. Proper iron allocation in the different organelles is thus critical to maintain cell function and integrity. To study the dynamics of iron distribution in plant cells, we have sought to identify the different intracellular iron pools by combining three complementary imaging approaches, histochemistry, micro particle-induced x-ray emission, and synchrotron radiation micro X-ray fluorescence. Pea (Pisum sativum) embryo was used as a model in this study because of its large cell size and high iron content. Histochemical staining with ferrocyanide and diaminobenzidine (Perls/diaminobenzidine) strongly labeled a unique structure in each cell, which co-labeled with the DNA fluorescent stain DAPI, thus corresponding to the nucleus. The unexpected presence of iron in the nucleus was confirmed by elemental imaging using micro particle-induced x-ray emission. X-ray fluorescence on cryo-sectioned embryos further established that, quantitatively, the iron concentration found in the nucleus was higher than in the expected iron-rich organelles such as plastids or vacuoles. Moreover, within the nucleus, iron was particularly accumulated in a subcompartment that was identified as the nucleolus as it was shown to transiently disassemble during cell division. Taken together, our data uncover an as yet unidentified although abundant iron pool in the cell, which is located in the nuclei of healthy, actively dividing plant tissues. This result paves the way for the discovery of a novel cellular function for iron related to nucleus/nucleolus-associated processes.

  14. Developmental patterns of jicama (Pachyrhizus erosus (L.) Urban) plant and the chemical constituents of roots grown in Sonora, Mexico.

    Science.gov (United States)

    Fernandez, M V; Warid, W A; Loaiza, J M; Montiel, A

    1997-01-01

    The developmental pattern of jicama (Pachyrhizus erosus (L.) Urban) was studied by sampling plants aged 20 to 36 weeks at weekly intervals. There was an increase in all characteristics of foliage: fresh and dry weight, number of leaves per plant, main stem length, number of leaves, nodes and internodes of the main stem; and in all root characteristics: fresh and dry weight, diameter and length. The chemical analysis was determined for roots at different plant ages. The range values for dry matter were 16.19-22.28%, protein 1.11-1.62%, fat 0.553-0.867%, crude fiber 0.3048-0.3943%, and ash 0.669-1.089%. The chemical constituents fluctuated with age but without specific trends. These values are considered the first record of roots produced by plants grown in Mexico.

  15. Developmental heterogeneity in DNA packaging patterns influences T-cell activation and transmigration.

    Directory of Open Access Journals (Sweden)

    Soumya Gupta

    Full Text Available Cellular differentiation programs are accompanied by large-scale changes in nuclear organization and gene expression. In this context, accompanying transitions in chromatin assembly that facilitates changes in gene expression and cell behavior in a developmental system are poorly understood. Here, we address this gap and map structural changes in chromatin organization during murine T-cell development, to describe an unusual heterogeneity in chromatin organization and associated functional correlates in T-cell lineage. Confocal imaging of DNA assembly in cells isolated from bone marrow, thymus and spleen reveal the emergence of heterogeneous patterns in DNA organization in mature T-cells following their exit from the thymus. The central DNA pattern dominated in immature precursor cells in the thymus whereas both central and peripheral DNA patterns were observed in naïve and memory cells in circulation. Naïve T-cells with central DNA patterns exhibited higher mechanical pliability in response to compressive loads in vitro and transmigration assays in vivo, and demonstrated accelerated expression of activation-induced marker CD69. T-cell activation was characterized by marked redistribution of DNA assembly to a central DNA pattern and increased nuclear size. Notably, heterogeneity in DNA patterns recovered in cells induced into quiescence in culture, suggesting an internal regulatory mechanism for chromatin reorganization. Taken together, our results uncover an important component of plasticity in nuclear organization, reflected in chromatin assembly, during T-cell development, differentiation and transmigration.

  16. Pigment cell interactions and differential xanthophore recruitment underlying zebrafish stripe reiteration and Danio pattern evolution.

    Science.gov (United States)

    Patterson, Larissa B; Bain, Emily J; Parichy, David M

    2014-11-06

    Fishes have diverse pigment patterns, yet mechanisms of pattern evolution remain poorly understood. In zebrafish, Danio rerio, pigment-cell autonomous interactions generate dark stripes of melanophores that alternate with light interstripes of xanthophores and iridophores. Here, we identify mechanisms underlying the evolution of a uniform pattern in D. albolineatus in which all three pigment cell classes are intermingled. We show that in this species xanthophores differentiate precociously over a wider area, and that cis regulatory evolution has increased expression of xanthogenic Colony Stimulating Factor-1 (Csf1). Expressing Csf1 similarly in D. rerio has cascading effects, driving the intermingling of all three pigment cell classes and resulting in the loss of stripes, as in D. albolineatus. Our results identify novel mechanisms of pattern development and illustrate how pattern diversity can be generated when a core network of pigment-cell autonomous interactions is coupled with changes in pigment cell differentiation.

  17. A comparative mechanical analysis of plant and animal cells reveals convergence across kingdoms.

    Science.gov (United States)

    Durand-Smet, Pauline; Chastrette, Nicolas; Guiroy, Axel; Richert, Alain; Berne-Dedieu, Annick; Szecsi, Judit; Boudaoud, Arezki; Frachisse, Jean-Marie; Bendahmane, Mohammed; Bendhamane, Mohammed; Hamant, Oliver; Asnacios, Atef

    2014-11-18

    Plant and animals have evolved different strategies for their development. Whether this is linked to major differences in their cell mechanics remains unclear, mainly because measurements on plant and animal cells relied on independent experiments and setups, thus hindering any direct comparison. In this study we used the same micro-rheometer to compare animal and plant single cell rheology. We found that wall-less plant cells exhibit the same weak power law rheology as animal cells, with comparable values of elastic and loss moduli. Remarkably, microtubules primarily contributed to the rheological behavior of wall-less plant cells whereas rheology of animal cells was mainly dependent on the actin network. Thus, plant and animal cells evolved different molecular strategies to reach a comparable cytoplasmic mechanical core, suggesting that evolutionary convergence could include the internal biophysical properties of cells.

  18. 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.

  19. Two glutamine synthetase genes from Phaseolus vulgaris L. display contrasting developmental and spatial patterns of expression in transgenic Lotus corniculatus plants.

    Science.gov (United States)

    Forde, B G; Day, H M; Turton, J F; Shen, W J; Cullimore, J V; Oliver, J E

    1989-04-01

    The gln-gamma gene, which specifies the gamma subunit of glutamine synthetase in Phaseolus vulgaris L., has been isolated and the regulatory properties of its promoter region analyzed in transgenic Lotus corniculatus plants. A 2-kilobase fragment from the 5'-flanking region of gln-gamma conferred a strongly nodule-enhanced pattern of expression on the beta-glucuronidase reporter gene. Parallel studies on the promoter of another glutamine synthetase gene (gln-beta) showed that a 1.7-kilobase fragment directed 20-fold to 140-fold higher levels of beta-glucuronidase expression in roots than in shoots. Histochemical localization of beta-glucuronidase activity in nodules of the transgenic plants indicated that the chimeric gln-gamma gene was expressed specifically in the rhizobially infected cells; expression of the gln-beta construct was detected in both cortical and infected regions of young nodules, and became restricted to the vascular tissue as the nodule matured. We conclude that gln-beta and gln-gamma genes are differentially expressed both temporally and spatially in plant development and that the cis-acting regulatory elements responsible for conferring these contrasting expression patterns are located within a 2-kilobase region upstream of their coding sequences.

  20. Embryonic control of epidermal cell patterning in the root and hypocotyl of Arabidopsis.

    Science.gov (United States)

    Lin, Y; Schiefelbein, J

    2001-10-01

    A position-dependent pattern of epidermal cell types is produced during the development of the Arabidopsis seedling root and hypocotyl. To understand the origin and regulation of this patterning mechanism, we have examined the embryonic expression of the GLABRA2 (GL2) gene, which encodes a cell-type-specific transcription factor. Using in situ RNA hybridization and a sensitive GL2::GFP reporter, we discovered that a position-dependent pattern of GL2 expression is established within protodermal cells at the heart stage and is maintained throughout the remainder of embryogenesis. In addition, we show that an exceptional GL2 expression character and epidermal cell pattern arises during development of the root-hypocotyl junction, which represents an anatomical transition zone. Furthermore, we find that two of the genes regulating seedling epidermal patterning, TRANSPARENT TESTA GLABRA (TTG) and WEREWOLF (WER), also control the embryonic GL2 pattern, whereas the CAPRICE (CPC) and GL2 genes are not required to establish this pattern. These results indicate that position-dependent patterning of epidermal cell types begins at an early stage of embryogenesis, before formation of the apical meristems and shortly after the cellular anatomy of the protoderm and outer ground tissue layer is established. Thus, epidermal cell specification in the Arabidopsis seedling relies on the embryonic establishment of a patterning mechanism that is perpetuated postembryonically.

  1. Effects of Simulated Grazing Pattern and Nitrogen Supply on Plant Growth in a Semiarid Region of Northern China

    Institute of Scientific and Technical Information of China (English)

    YUANZhi-You; LILing-Hao; HANXing-Guo; JIANGFeng-He; LINGuo-Hui; ZHAOMing-Xu; RENLi-Yun

    2004-01-01

    Grazing in grassland ecosystems affects plant growth by removing biomass and depositing excretal nutrients. However, grazing is not uniformly distributed in space. The spatial pattern of defoliation and excretion deposition by herbivores across vegetation mosaics has been frequently discussed, but rarely spatially quantified. A 60-day field experiment in a native semiarid grassland community was conducted to examine the responses of plant growth to simulated grazing pattern and varying nitrogen levels.Plants were subjected to five defoliation treatments determined by circularly clipped patches of different size (0, 10, 20, 40, 80cm in radius), and four nitrogen supply levels in soils (0, 5, 10, 20g N/m2). It was detected that defoliation had reduced primary productivity by 41.5% whereas fertilization had increased it by 57.8%. The negative effect of defoliation was greater in the smallest, fertilized patches. N addition had been found to have altered the effect of defoliation, as plants growing at higher nitrogen levels were more negatively affected by defoliation than plants with no supplementary application of nitrogen. These results indicated that the magnitude of defoliation response for an individual plant was modulated by not only defoliation itself, but also other factors, such as nutrient availability, The increase in the ratio of live to dead plant parts suggested that urine deposition delayed the senescence of plants. The results also showed that (1) the effect of defoliation on primary productivity was affected by the patch size, and (2) nitrogen addition (simulated urine deposition) could increase primary productivity and affect the response to defoliation more obviously in the smaller patches than in the larger ones.

  2. Fuel Cell Balance-of-Plant Reliability Testbed Project

    Energy Technology Data Exchange (ETDEWEB)

    Sproat, Vern [Stark State College of Technology, North Canton, OH (United States); LaHurd, Debbie [Lockheed Martin Corp., Oak Ridge, TN (United States)

    2016-10-29

    Reliability of the fuel cell system balance-of-plant (BoP) components is a critical factor that needs to be addressed prior to fuel cells becoming fully commercialized. Failure or performance degradation of BoP components has been identified as a life-limiting factor in fuel cell systems.1 The goal of this project is to develop a series of test beds that will test system components such as pumps, valves, sensors, fittings, etc., under operating conditions anticipated in real Polymer Electrolyte Membrane (PEM) fuel cell systems. Results will be made generally available to begin removing reliability as a roadblock to the growth of the PEM fuel cell industry. Stark State College students participating in the project, in conjunction with their coursework, have been exposed to technical knowledge and training in the handling and maintenance of hydrogen, fuel cells and system components as well as component failure modes and mechanisms. Three test beds were constructed. Testing was completed on gas flow pumps, tubing, and pressure and temperature sensors and valves.

  3. Temporal properties of pattern adaptation of relay cells in the lateral geniculate nucleus of cats

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The temporal properties of pattern adaptation of relay cells induced by repeated sinusoidal drifting grating were investigated in the dorsal lateral geniculate nucleus (dLGN) of cats. The results showed that the response amplitude declined and the response latency prolonged when relay cells were pattern-adapted in dLGN, like the similar fmdings in visual cortex. However, in contrast to the result in cortex,the response phase of relay cells advanced. This implies that an inhibition with relatively long latency may participate in the pattern adaptation of dLGN cells and the adaptation in dLGN may be via a mechanism different from that of visual cortex.``

  4. A phyletic perspective on the allometry of plant biomass-partitioning patterns and functionally equivalent organ-categories.

    Science.gov (United States)

    Niklas, Karl J

    2006-01-01

    Biomass-partitioning patterns influence the functioning of aquatic and terrestrial vegetation at all levels, ranging from individual growth and reproduction to the flow of mass and energy through entire communities. For this reason, leaf, stem and root dry biomass-partitioning patterns across taxonomically and ecologically diverse seed plants (spermatophytes) have been intensively investigated, both empirically and theoretically. By contrast, phyletically disparate plants (e.g. green and brown algal macrophytes, mosses and pteridophytes) have not been examined to determine whether the partitioning of their body parts into 'leaf', 'stem' and 'root' analogs accords with that of spermatophytes. In this review, the biomass-partitioning patterns of siphonous and brown algal macrophytes, mosses and pteridophytes were compared allometrically with those of spermatophytes and were shown to be largely in statistical accordance (thus lending support to the hypothesis that a single scaling relationship exists across eukaryotic photoautotrophs). This concordance is argued to support the hypothesis of functional equivalence across analogous, but developmentally different, body parts, a feature that permits the use of simpler biological model systems with which to derive analytical explanations for the biomass-partitioning patterns reported for more complex seed plants.

  5. 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.

  6. The use of phylogeny to interpret cross-cultural patterns in plant use and guide medicinal plant discovery: an example from Pterocarpus (Leguminosae.

    Directory of Open Access Journals (Sweden)

    C Haris Saslis-Lagoudakis

    Full Text Available 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. Phylogenetic tools have entered many scientific fields in the last two decades to provide explanatory power, but have been overlooked in ethnomedicinal studies. Several studies show that medicinal properties are not randomly distributed in plant phylogenies, suggesting that phylogeny shapes ethnobotanical use. Nevertheless, empirical studies that explicitly combine ethnobotanical and phylogenetic information are scarce. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we borrowed tools from community ecology phylogenetics to quantify significance of phylogenetic signal in medicinal properties in plants and identify nodes on phylogenies with high bioscreening potential. To do this, we produced an ethnomedicinal review from extensive literature research and a multi-locus phylogenetic hypothesis for the pantropical genus Pterocarpus (Leguminosae: Papilionoideae. We demonstrate that species used to treat a certain conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic relationships. CONCLUSIONS/SIGNIFICANCE: This study provides techniques that enable the application of phylogenies in bioscreening, but also sheds light on the processes that shape cross-cultural ethnomedicinal patterns. This community phylogenetic approach demonstrates that similar ethnobotanical uses can arise in parallel in different areas where related plants are available. With a vast amount of ethnomedicinal and phylogenetic information available, we

  7. A radioimmunoassay for lignin in plant cell walls

    Energy Technology Data Exchange (ETDEWEB)

    Dawley, R.M.

    1989-01-01

    Lignin detection and determination in herbaceous tissue requires selective, specific assays which are not currently available. A radioimmunoassay (RIA) was developed to study lignin metabolism in these tissues. A {beta}-aryl ether lignin model compound was synthesized, linked to keyhole limpet hemocyanin using a water-soluble carbodiimide, and injected into rabbits. The highest titer of the antiserum obtained was 34 {eta}g/mL of model derivatized BSA. An in vitro system was developed to characterize the RIA. The model compound was linked to amino activated polyacrylamide beads to mimic lignin in the cell walls. {sup 125}I Radiolabelled protein A was used to detect IgG antibody binding. The RIA was shown in the in vitro system to exhibit saturable binding. The amount of antibody bound decreased when the serum was diluted. Immunoelectrophoresis and competitive binding experiments confirmed that both aromatic rings of the lignin model compound had been antigenic. Chlorogenic acid, a phenolic known to be present in plant cells, did not compete for antibody binding. The RIA was used to measure lignin in milled plant samples and barley seedlings. Antiserum binding to wheat cell walls and stressed barley segments was higher than preimmune serum binding. Antibody binding to stressed barley tissue decreased following NaClO{sub 2} delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed.

  8. Patterning of cell assemblies regulated by adhesion receptors of the cadherin superfamily.

    Science.gov (United States)

    Takeichi, M; Nakagawa, S; Aono, S; Usui, T; Uemura, T

    2000-07-29

    During morphogenesis, cell-cell association patterns are dynamically altered. We are interested in how cell adhesion molecules can regulate the patterning of cellular assemblies. Cadherins, a group of cell-cell adhesion receptors, are crucial for the organized assembly of many cell types, but they also regulate dynamic aspects of cell association. For example, during neural crest emigration from the neural tube, the cadherin subtypes expressed by crest cells are switched from one subtype to another. Artificial perturbation of this switch results in blocking of their escape from the neural tube. Intracellular modulations of cadherin activity also seem to play a role in regulation of cell adhesion. We identified p120ctn as a regulator of cadherin function in carcinoma cells. With such regulators, cells may make a choice as to whether they should maintain stable cell contacts or disrupt their association. Finally, we found another type of cadherin-mediated cell patterning: Flamingo, a seven-pass transmembrane cadherin, regulates planar cell polarity in Drosophila imaginal discs. Thus, the cadherin superfamily receptors control the patterning of cell assemblies through a variety of mechanisms.

  9. Microfluidic monitoring of programmed cell death in living plant seed tissue

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Zor, Kinga

    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...

  10. Long-term patterns in tropical reforestation: plant community composition and aboveground biomass accumulation.

    Science.gov (United States)

    Marín-Spiotta, E; Ostertag, R; Silver, W L

    2007-04-01

    Primary tropical forests are renowned for their high biodiversity and carbon storage, and considerable research has documented both species and carbon losses with deforestation and agricultural land uses. Economic drivers are now leading to the abandonment of agricultural lands, and the area in secondary forests is increasing. We know little about how long it takes for these ecosystems to achieve the structural and compositional characteristics of primary forests. In this study, we examine changes in plant species composition and aboveground biomass during eight decades of tropical secondary succession in Puerto Rico, and compare these patterns with primary forests. Using a well-replicated chronosequence approach, we sampled primary forests and secondary forests established 10, 20, 30, 60, and 80 years ago on abandoned pastures. Tree species composition in all secondary forests was different from that of primary forests and could be divided into early (10-, 20-, and 30-year) vs. late (60- and 80-year) successional phases. The highest rates of aboveground biomass accumulation occurred in the first 20 years, with rates of C sequestration peaking at 6.7 +/- 0.5 Mg C x ha(-1) x yr(-1). Reforestation of pastures resulted in an accumulation of 125 Mg C/ha in aboveground standing live biomass over 80 years. The 80 year-old secondary forests had greater biomass than the primary forests, due to the replacement of woody species by palms in the primary forests. Our results show that these new ecosystems have different species composition, but similar species richness, and significant potential for carbon sequestration, compared to remnant primary forests.

  11. Adhesive-tape soft lithography for patterning mammalian cells: application to wound-healing assays.

    Science.gov (United States)

    Shrirao, Anil B; Hussain, Ali; Cho, Cheul H; Perez-Castillejos, Raquel

    2012-09-13

    This paper introduces a benchtop method for patterning mammalian cells-i.e., for culturing cells at specific locations-on planar substrates. Compared with standard cell culture techniques, which do not allow the control of what areas of a monolayer are populated by one type of cell or another, techniques of cell patterning open new routes to cell biology. Researchers interested in cell patterning, however, are often times hindered by limited access to photolithographic capabilities. This paper shows how cells can be patterned easily with sub-millimeter precision using a non-photolithographic technique that is based on the use of office adhesive tape and poly(dimethylsiloxane) (PDMS). This method is fast (~4 h to go from a layout to have the cells patterned in the shape of such layout) and only requires materials and tools readily available in a conventional biomedical laboratory. A wound-healing assay is presented here that illustrates the potential of the technique (which we call tape-based soft lithography) for patterning mammalian cells and studying biologically significant questions such as collective cellular migration.

  12. Control of patterns of symmetric cell division in the epidermal and cortical tissues of the Arabidopsis root.

    Science.gov (United States)

    Zhang, Yanwen; Iakovidis, Michail; Costa, Silvia

    2016-03-15

    Controlled cell division is central to the growth and development of all multicellular organisms. Within the proliferating zone of the Arabidopsis root, regular symmetric divisions give rise to patterns of parallel files of cells, the genetic basis of which remains unclear. We found that genotypes impaired in the TONNEAU1a (TON1a) gene display misoriented symmetric divisions in the epidermis and have no division defects in the underlying cortical tissue. The TON1a gene encodes a microtubule-associated protein. We show that in the ton1a mutant, epidermal and cortical cells do not form narrow, ring-like preprophase bands (PPBs), which are plant-specific, cytoskeletal structures that predict the position of the division plane before mitosis. The results indicate that in the cortex but not in the epidermis, division plane positioning and patterning can proceed correctly in the absence of both a functional TON1a and PPB formation. Differences between tissues in how they respond to the signals that guide symmetric division orientation during patterning might provide the basis for organised organ growth in the absence of cell movements.

  13. Effects of real or simulated microgravity on plant cell growth and proliferation

    Science.gov (United States)

    Medina, Francisco Javier; Manzano, Ana Isabel; Herranz, Raul; Dijkstra, Camelia; Larkin, Oliver; Hill, Richard; Carnero-Díaz, Eugénie; van Loon, Jack J. W. A.; Anthony, Paul; Davey, Michael R.; Eaves, Laurence

    Experiments on seed germination and seedling growth performed in real microgravity on the International Space Station and in different facilities for simulating microgravity in Earth-based laboratories (Random Positioning Machine and Magnetic Levitation), have provided evidence that the absence of gravity (or the artificial compensation of the gravity vector) results in the uncoupling of cell growth and proliferation in root meristematic cells. These are two essential cellular functions that support plant growth and development, which are strictly coordinated under normal ground gravity conditions. Under conditions of altered gravity, we observe that cell proliferation is enhanced, whereas cell growth is reduced, according to different morphometric, cytological and immunocytochemical parameters. Since coordination of cell growth and proliferation are major features of meristematic cells, this observed uncoupling represents a major stress condition for these cells, inducing major alterations in the pattern of plant development. Moreover, the expression of the cyclin B1 gene, a regulator of the entry into mitosis and normally used as an indicator of cell proliferation, appears reduced in the smaller and more actively proliferating cells of samples grown under the conditions of our experiments. These results are compatible with an alteration of the regulation of the cell cycle, producing a shorter G2 period. Interestingly, while cyclin B1 expression is depleted in these conditions in root meristematic cells, it is enhanced in cotyledons of the same seedlings, as shown by qPCR and by the expression of the gus reporter gene. It is known that regulation of root growth (including regulation of root meristematic activity) is driven mainly by auxin, whereas cytokinin is the key hormone regulating cotyledon growth. Therefore, our results indicate a major role of auxin in the sensitivity to altered gravity of root meristematic cells. Auxin is crucial in maintaining the

  14. Optimal shapes and stresses of adherent cells on patterned substrates

    CERN Document Server

    Banerjee, Shiladitya; Marchetti, M Cristina

    2013-01-01

    We investigate a continuum mechanical model for an adherent cell on two dimensional adhesive micropatterned substrates. The cell is modeled as an isotropic and homogeneous elastic material subject to uniform internal contractile stresses. The build-up of tension from cortical actin bundles at the cell periphery is incorporated by introducing an energy cost for bending of the cell boundary, resulting to a resistance to changes in local curvature. Integrin-based adhesions are modeled as harmonic springs, that pin the cell to adhesive patches of a predefined geometry. Using Monte Carlo simulations and analytical techniques we investigate the competing effects of bulk contractility and cortical bending rigidity in regulating cell shapes on non-adherent regions. We show that the crossover from convex to concave cell edges is controlled by the interplay between contractile stresses and boundary bending rigidity. In particular, the cell boundary becomes concave beyond a critical value of the contractile stress that ...

  15. 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

  16. 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

  17. 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%.

  18. 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

    conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic...

  19. Novel roles of plant RETINOBLASTOMA-RELATED (RBR) protein in cell proliferation and asymmetric cell division.

    Science.gov (United States)

    Desvoyes, Bénédicte; de Mendoza, Alex; Ruiz-Trillo, Iñaki; Gutierrez, Crisanto

    2014-06-01

    The retinoblastoma (Rb) protein was identified as a human tumour suppressor protein that controls various stages of cell proliferation through the interaction with members of the E2F family of transcription factors. It was originally thought to be specific to animals but plants contain homologues of Rb, called RETINOBLASTOMA-RELATED (RBR). In fact, the Rb-E2F module seems to be a very early acquisition of eukaryotes. The activity of RBR depends on phosphorylation of certain amino acid residues, which in most cases are well conserved between plant and animal proteins. In addition to its role in cell-cycle progression, RBR has been shown to participate in various cellular processes such as endoreplication, transcriptional regulation, chromatin remodelling, cell growth, stem cell biology, and differentiation. Here, we discuss the most recent advances to define the role of RBR in cell proliferation and asymmetric cell division. These and other reports clearly support the idea that RBR is used as a landing platform of a plethora of cellular proteins and complexes to control various aspects of cell physiology and plant development.

  20. Cytoplasmic streaming in plant cells: the role of wall slip.

    Science.gov (United States)

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

    2012-06-01

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

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

    Science.gov (United States)

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

    2002-01-01

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

  2. Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern

    Science.gov (United States)

    Go, Bit-Na; Kim, Yang Doo; suk Oh, Kyoung; Kim, Chaehyun; Choi, Hak-Jong; Lee, Heon

    2014-09-01

    To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively.

  3. 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

    in the context of species distribution patterns observed in macroecology, and we summarize observations about the processes involved in co-adaptation between P. putida and Acinetobacter sp. C6. Our results contribute to an understanding of spatial species distribution patterns as they are observed in nature......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...... a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. In this consortium, P. putida is reliant on microcolonies formed by Acinetobacter sp. C6 — to which it attaches. Here we describe the processes that lead to the microcolony...

  4. Cell-to-cell communication in plants, animals, and fungi: a comparative review.

    Science.gov (United States)

    Bloemendal, Sandra; Kück, Ulrich

    2013-01-01

    Cell-to-cell communication is a prerequisite for differentiation and development in multicellular organisms. This communication has to be tightly regulated to ensure that cellular components such as organelles, macromolecules, hormones, or viruses leave the cell in a precisely organized way. During evolution, plants, animals, and fungi have developed similar ways of responding to this biological challenge. For example, in higher plants, plasmodesmata connect adjacent cells and allow communication to regulate differentiation and development. In animals, two main general structures that enable short- and long-range intercellular communication are known, namely gap junctions and tunneling nanotubes, respectively. Finally, filamentous fungi have also developed specialized structures called septal pores that allow intercellular communication via cytoplasmic flow. This review summarizes the underlying mechanisms for intercellular communication in these three eukaryotic groups and discusses its consequences for the regulation of differentiation and developmental processes.

  5. Cell-to-cell communication in plants, animals, and fungi: a comparative review

    Science.gov (United States)

    Bloemendal, Sandra; Kück, Ulrich

    2013-01-01

    Cell-to-cell communication is a prerequisite for differentiation and development in multicellular organisms. This communication has to be tightly regulated to ensure that cellular components such as organelles, macromolecules, hormones, or viruses leave the cell in a precisely organized way. During evolution, plants, animals, and fungi have developed similar ways of responding to this biological challenge. For example, in higher plants, plasmodesmata connect adjacent cells and allow communication to regulate differentiation and development. In animals, two main general structures that enable short- and long-range intercellular communication are known, namely gap junctions and tunneling nanotubes, respectively. Finally, filamentous fungi have also developed specialized structures called septal pores that allow intercellular communication via cytoplasmic flow. This review summarizes the underlying mechanisms for intercellular communication in these three eukaryotic groups and discusses its consequences for the regulation of differentiation and developmental processes.

  6. 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.

  7. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2

    Science.gov (United States)

    Chaparro-Garcia, Angela; Schwizer, Simon; Sklenar, Jan; Yoshida, Kentaro; Petre, Benjamin; Bos, Jorunn I. B.; Schornack, Sebastian; Jones, Alexandra M. E.; Bozkurt, Tolga O.; Kamoun, Sophien

    2015-01-01

    Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity). However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2), a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways. PMID:26348328

  8. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2.

    Directory of Open Access Journals (Sweden)

    Angela Chaparro-Garcia

    Full Text Available Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity. However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2, a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways.

  9. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2.

    Science.gov (United States)

    Chaparro-Garcia, Angela; Schwizer, Simon; Sklenar, Jan; Yoshida, Kentaro; Petre, Benjamin; Bos, Jorunn I B; Schornack, Sebastian; Jones, Alexandra M E; Bozkurt, Tolga O; Kamoun, Sophien

    2015-01-01

    Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity). However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2), a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways.

  10. Above–belowground herbivore interactions in mixed plant communities are influenced by altered precipitation patterns

    OpenAIRE

    2016-01-01

    Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralisation and uptake by neighbouring plants and influence plant–plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N) from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community compositi...

  11. Measuring NO Production by Plant Tissues and Suspension Cultured Cells

    Institute of Scientific and Technical Information of China (English)

    Jan Vitecek; Vilem Reinohl; Russell L.Jones

    2008-01-01

    We describe an inexpensive and reliable detector for measuring NO emitted in the gas phase from plants.The method relies on the use of a strong oxidizer to convert NO to NO2 and subsequent capture of NO2 by a Griess reagent trap.The set-up approaches the sensitivity for NO comparable to that of instruments based on chemiluminescence and photoacoustic detectors.We demonstrate the utility of our set-up by measuring NO produced by a variety of well established plant sources.NO produced by nitrate reductase (NR) in tobacco leaves and barley aleurone was readily detected,as was the production of NO from nitrite by the incubation medium of barley aleurone.Arabidopsis mutants that overproduce NO or lack NO-synthase (AtNOS1) also displayed the expected NO synthesis phenotype when assayed by our set-up.We could also measure NO production from elicitor-treated suspension cultured cells using this set-up.Further,we have focused on the detection of NO by a widely used fluorescent probe 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM).Our work points to the pitfalls that must be avoided when using DAF-FM to detect the production of NO by plant tissues.In addition to the dramatic effects that pH can have on fluorescence from DAF-FM,the widely used NO scavengers 2-phenyl-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (PTIO) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) can produce anomalous and unexpected results.Perhaps the most serious drawback of DAF-FM is its ability to bind to dead cells and remain NO-sensitive.

  12. 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

    2015-01-01

    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.

  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. A feedback mechanism controlling SCRAMBLED receptor accumulation and cell-type pattern in Arabidopsis.

    Science.gov (United States)

    Kwak, Su-Hwan; Schiefelbein, John

    2008-12-23

    Cellular pattern formation in the root epidermis of Arabidopsis occurs in a position-dependent manner, generating root-hair (H) cells contacting two underlying cortical cells and nonhair (N) cells contacting one cortical cell. SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase (LRR-RLK), mediates this process through its effect on a downstream transcription factor regulatory network. After perception of a positional cue, the SCM signaling pathway is proposed to preferentially repress WEREWOLF (WER) transcription factor expression in H cells and thereby bias the outcome of mutual lateral inhibition acting between H and N cells. However, the molecular mechanism responsible for this preferential SCM signaling is unknown. Here, we analyze the distribution of the SCM receptor and the biological effect of altering its accumulation pattern. We find that SCM expression and accumulation in the epidermal cell layer is necessary and sufficient to direct the cell-type pattern. Further, SCM preferentially accumulates in H cells, and this accumulation pattern is dependent on the downstream transcription factors. Thus, SCM participates in an autoregulatory feedback loop, enabling cells engaged in SCM signaling to maintain high levels of SCM receptor, which provides a simple mechanism for reinforcing a bias in receptor-mediated signaling to ensure robust pattern formation.

  15. 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

  16. 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.

  17. Transformation of haploid Datura innoxia protoplasts and analysis of the plasmid integration pattern in regenerated transgenic plants.

    Science.gov (United States)

    Schmidt-Rogge, T; Meixner, M; Srivastava, V; Guha-Mukherjee, S; Schieder, O

    1993-05-01

    We developed a highly efficient transformation protocol for the PEG-mediated direct transfer of plasmid DNA into protoplasts of haploid Datura innoxia. Vectors harbouring a neomycin phosphotransferase II gene or a hygromycin B phosphotransferase gene under the control of different promoters were used in the transformation experiments. Various amounts of plasmid DNA were applied without any carrier DNA to show the direct influence of the plasmid DNA concentration on the transformation efficiency. Approximately 95% of the selected calli were regenerated to plants; 20% of them remained haploid. Total DNA of different transgenic plants was analysed with regard to the integration pattern of the plasmid DNA. Plants carrying only one or two copies of the vector DNA were observed as well as individuals with multi-copy integration (up to ten or more copies).

  18. 植物与建筑造景模式探讨%Inquiry on plants and building landscaping pattern

    Institute of Scientific and Technical Information of China (English)

    罗建伟

    2011-01-01

    This paper inquires the plants and building landscaping pattern,analyzes the unification and variation of plants and building landscaping,and describes the application of coordination and comparison in plants and building landscaping,balance and stability%针对植物与建筑造景模式进行了探讨,分析了植物与建筑组景中的统一与变化,并阐述了植物与建筑组景中协调和对比的应用,植物与建筑的均衡和稳定等内容,以期指导环境景观设计工作。

  19. JACKDAW controls epidermal patterning in the Arabidopsis root meristem through a non-cell-autonomous mechanism.

    Science.gov (United States)

    Hassan, Hala; Scheres, Ben; Blilou, Ikram

    2010-05-01

    In Arabidopsis, specification of the hair and non-hair epidermal cell types is position dependent, in that hair cells arise over clefts in the underlying cortical cell layer. Epidermal patterning is determined by a network of transcriptional regulators that respond to an as yet unknown cue from underlying tissues. Previously, we showed that JACKDAW (JKD), a zinc finger protein, localizes in the quiescent centre and the ground tissue, and regulates tissue boundaries and asymmetric cell division by delimiting SHORT-ROOT movement. Here, we provide evidence that JKD controls position-dependent signals that regulate epidermal-cell-type patterning. JKD is required for appropriately patterned expression of the epidermal cell fate regulators GLABRA2, CAPRICE and WEREWOLF. Genetic interaction studies indicate that JKD operates upstream of the epidermal patterning network in a SCRAMBLED (SCM)-dependent fashion after embryogenesis, but acts independent of SCM in embryogenesis. Tissue-specific induction experiments indicate non-cell-autonomous action of JKD from the underlying cortex cell layer to specify epidermal cell fate. Our findings are consistent with a model where JKD induces a signal in every cortex cell that is more abundant in the hair cell position owing to the larger surface contact of cells located over a cleft.

  20. Effects of planting pattern and density on growth indices, yield and yield component of corn (Zea mays in competition with redroot pigweed (Amaranthus retrofelexus(

    Directory of Open Access Journals (Sweden)

    alireza barkhi

    2009-06-01

    Full Text Available An experiment was conducted in 2002-2003 using split-split plot arrangement based on Rondomised Compelete Block Design with three replications at Feiz Abad Agricultural Research Station of Qazvin, in order to study of planting patterns and corn densitis effect in competition with redroot pigweed. Main plots inclouded two planting pattern of corn (P1: single row and P2: double row, sub plots inclouded two corn densities (D1:7 and D2:10 plant/m2 and sub sub plots inclouded 4 weed densities (C1:0, C2:2, C3:6, C4:12 plant/m2. Sampling conducted in 2-weekly intervals and growth indices evaluated. Results indicated that with increasing of weed density CGR, TDW, LAI, number of seeds in row, grain and ear yield decreased but plant height increased. Also LAI, CGR, TDW, number of weed seed and seed,s weight of weed increased. By increasing in corn density LAI, CGR, TDW, ear and grain yield increased, but length and diameter of ear and number of seeds in row decreased. Also LAI and CGR of weed increased, but TDW was decreased. In double row planting pattern just CGR, LAI, TDW of corn were higher significantly than single row planting pattern. But single row planting of weed caused higher LAI, NAR, RGR, CGR and TDW of weed in comparison with double row planting pattern. In 2-way interaction, double row planting pattern and zero densities and 2 weeds/m2 had highest grain yield respectively. There were no significant differences for 3-way interactions but double row planting pattern 10 plant density of corn/m2 zero weed/ m2 had highest grain yield.

  1. Guiding plant virus particles to integrin-displaying cells

    Science.gov (United States)

    Hovlid, Marisa L.; Steinmetz, Nicole F.; Laufer, Burkhardt; Lau, Jolene L.; Kuzelka, Jane; Wang, Qian; Hyypiä, Timo; Nemerow, Glen R.; Kessler, Horst; Manchester, Marianne; Finn, M. G.

    2012-05-01

    Viral nanoparticles (VNPs) are structurally regular, highly stable, tunable nanomaterials that can be conveniently produced in high yields. Unmodified VNPs from plants and bacteria generally do not show tissue specificity or high selectivity in binding to or entry into mammalian cells. They are, however, malleable by both genetic and chemical means, making them useful scaffolds for the display of large numbers of cell- and tissue-targeting ligands, imaging moieties, and/or therapeutic agents in a well-defined manner. Capitalizing on this attribute, we modified the genetic sequence of the Cowpea mosaic virus (CPMV) coat protein to display an RGD oligopeptide sequence derived from human adenovirus type 2 (HAdV-2). Concurrently, wild-type CPMV was modified via NHS acylation and Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) chemistry to attach an integrin-binding cyclic RGD peptide. Both types of particles showed strong and selective affinity for several different cancer cell lines that express RGD-binding integrin receptors.Viral nanoparticles (VNPs) are structurally regular, highly stable, tunable nanomaterials that can be conveniently produced in high yields. Unmodified VNPs from plants and bacteria generally do not show tissue specificity or high selectivity in binding to or entry into mammalian cells. They are, however, malleable by both genetic and chemical means, making them useful scaffolds for the display of large numbers of cell- and tissue-targeting ligands, imaging moieties, and/or therapeutic agents in a well-defined manner. Capitalizing on this attribute, we modified the genetic sequence of the Cowpea mosaic virus (CPMV) coat protein to display an RGD oligopeptide sequence derived from human adenovirus type 2 (HAdV-2). Concurrently, wild-type CPMV was modified via NHS acylation and Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) chemistry to attach an integrin-binding cyclic RGD peptide. Both types of particles showed strong and selective affinity

  2. 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

  3. Cell patterning on polylactic acid through surface-tethered oligonucleotides.

    Science.gov (United States)

    Matsui, Toshiki; Arima, Yusuke; Takemoto, Naohiro; Iwata, Hiroo

    2015-02-01

    Polylactic acid (PLA) is a candidate material to prepare scaffolds for 3-D tissue regeneration. However, cells do not adhere or proliferate well on the surface of PLA because it is hydrophobic. We report a simple and rapid method for inducing cell adhesion to PLA through DNA hybridization. Single-stranded DNA (ssDNA) conjugated to poly(ethylene glycol) (PEG) and to a terminal phospholipid (ssDNA-PEG-lipid) was used for cell surface modification. Through DNA hybridization, modified cells were able to attach to PLA surfaces modified with complementary sequence (ssDNA'). Different cell types can be attached to PLA fibers and films in a spatially controlled manner by using ssDNAs with different sequences. In addition, they proliferate well in a culture medium supplemented with fetal bovine serum. The coexisting modes of cell adhesion through DNA hybridization and natural cytoskeletal adhesion machinery revealed no serious effects on cell growth. The combination of a 3-D scaffold made of PLA and cell immobilization on the PLA scaffold through DNA hybridization will be useful for the preparation of 3-D tissue and organs.

  4. Epidermal Patterning Genes Impose Non-cell Autonomous Cell Size Determination and have Additional Roles in Root Meristem Size Control

    Institute of Scientific and Technical Information of China (English)

    Christian L?fke; Kai Dünser; Jürgen Kleine-Vehn

    2013-01-01

    The regulation of cellular growth is of vital importance for embryonic and postembryonic patterning. Growth regulation in the epidermis has importance for organ growth rates in roots and shoots, proposing epidermal cells as an interesting model for cellular growth regulation. Here we assessed whether the root epidermis is a suitable model system to address cell size determination. In Arabidopsis thaliana L., root epidermal cells are regularly spaced in neighbouring tricho-(root hair) and atrichoblast (non-hair) cells, showing already distinct cell size regulation in the root meristem. We determined cell sizes in the root meristem and at the onset of cellular elongation, revealing that not only division rates but also cellular shape is distinct in tricho-and atrichoblasts. Intriguingly, epidermal-patterning mutants, failing to define differential vacuolization in neighbouring epidermal cell files, also display non-differential growth. Using these epidermal-patterning mutants, we show that polarized growth behaviour of epidermal tricho-and atrichoblast is interdependent, suggesting non-cell autonomous signals to integrate tissue expansion. Besides the interweaved cell-type-dependent growth mechanism, we reveal an additional role for epidermal patterning genes in root meristem size and organ growth regulation. We conclude that epidermal cells represent a suitable model system to study cell size determination and interdependent tissue growth.

  5. Plant protoplast fusion and growth of intergeneric hybrid cells.

    Science.gov (United States)

    Kao, K N; Constabel, F; Michayluk, M R; Gamborg, O L

    1974-01-01

    Interspecific and intergeneric fusions of plant protoplasts were induced by polyethylene glycol (PEG) 1540 or 4000. The frequency of heterokaryocyte formation (or rate of fusion) was much higher when PEG was eluted with a high pH-high Ca(2+) solution or a salt solution than when it was eluted with a protoplast culture medium. The frequency of heterokaryocyte formation was also affected by the types of enzymes used for wall degradation, duration of enzyme incubation and molality of the PEG solutions.The maximum frequency of heterokaryocyte formation was 23% for V. hajastana Grossh.-soybean (Glycine max L.) and barley (Hordeum vulgare L.)-soybean, 35% for pea (Pisum sativum L.)-soybean, 20% for pea-V. hajastana, 14% for corn (Zea mays L.)-soybean and 10% for V. villosa Roth-V. hajastana.40% of the barley-soybean, corn-soybean and pea-soybean heterokaryocytes divided at least once. Some divided many times and formed clusters of up to 100 cells in 2 weeks. The heterokaryocytes of soybean-V. hajastana, V. villosa-V. hajastana also divided. Of the PEG-treated protoplasts of N. langsdorffii and N. glauca 13.5% developed into tumor-like calli. The morphology of these calli was very much like that of the tumors produced on amphidiploid plants of N. langsdorffii x glauca.Nuclear staining indicated that heterokaryocytes of V. hajastana-soybean, pea-soybean, corn-soybean and barley-soybean could undergo mitosis. Nuclear divisions in a heterokaryocyte were usually synchronized or almost synchronized. Nuclear fusion and true hybrid formation usually occurred during the first mitotic division after protoplast fusion. A hybrid of barley-soybean in third cell division was observed. The frequency of heterokaryocytes which underwent nuclear fusion has not been determined. Multipole formation and chimeral cell colonies were also observed.

  6. A fuel cell balance of plant test facility

    Science.gov (United States)

    Dicks, A. L.; Martin, P. A.

    Much attention is focused in the fuel cell community on the development of reliable stack technology, but to successfully exploit fuel cells, they must form part of integrated power generation systems. No universal test facilities exist to evaluate SOFC stacks and comparatively little research has been undertaken concerning the issues of the rest of the system, or balance of plant (BOP). BG, in collaboration with Eniricerche, has therefore recently designed and built a test facility to evaluate different configurations of the BOP equipment for a 1-5 kWe solid oxide fuel cell (SOFC) stack. Within this BOP project, integrated, dynamic models have been developed. These have shown that three characteristic response times exist when the stack load is changed and that three independent control loops are required to manage the almost instantaneous change in power output from an SOFC stack, maintain the fuel utilisation and control the stack temperature. Control strategies and plant simplifications, arising from the dynamic modelling, have also been implemented in the BOP test facility. An SOFC simulator was designed and integrated into the control system of the test rig to behave as a real SOFC stack, allowing the development of control strategies without the need for a real stack. A novel combustor has been specifically designed, built and demonstrated to be capable of burning the low calorific anode exhaust gas from an SOFC using the oxygen depleted cathode stream. High temperature, low cost, shell and tube heat exchangers have been shown to be suitable for SOFC systems. Sealing of high temperature anode recirculation fans has, however, been shown to be a major issue and identified as a key area for further investigation.

  7. 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.

  8. Biased inheritance of the protein PatN frees vegetative cells to initiate patterned heterocyst differentiation.

    Science.gov (United States)

    Risser, Douglas D; Wong, Francis C Y; Meeks, John C

    2012-09-18

    Heterocysts, cells specialized for nitrogen fixation in certain filamentous cyanobacteria, appear singly in a nonrandom spacing pattern along the chain of vegetative cells. A two-stage, biased initiation and competitive resolution model has been proposed to explain the establishment of this spacing pattern. There is substantial evidence that competitive resolution of a subset of cells initiating differentiation occurs by interactions between a self-enhancing activator protein, HetR, and a diffusible pentapeptide inhibitor PatS-5 (RGSGR). Results presented here show that the absence of a unique membrane protein, PatN, in Nostoc punctiforme strain ATCC 29133 leads to a threefold increase in heterocyst frequency and a fourfold decrease in the vegetative cell interval between heterocysts. A PatN-GFP translational fusion shows a pattern of biased inheritance in daughter vegetative cells of ammonium-grown cultures. Inactivation of another heterocyst patterning gene, patA, is epistatic to inactivation of patN, and transcription of patA increases in a patN-deletion strain, implying that patN may function by modulating levels of patA. The presence of PatN is hypothesized to decrease the competency of a vegetative cell to initiate heterocyst differentiation, and the cellular concentration of PatN is dependent on cell division that results in cells transiently depleted of PatN. We suggest that biased inheritance of cell-fate determinants is a phylogenetic domain-spanning paradigm in the development of biological patterns.

  9. A dynamic model for stem cell homeostasis and patterning in Arabidopsis meristems.

    Directory of Open Access Journals (Sweden)

    Tim Hohm

    Full Text Available Plants maintain stem cells in their meristems as a source for new undifferentiated cells throughout their life. Meristems are small groups of cells that provide the microenvironment that allows stem cells to prosper. Homeostasis of a stem cell domain within a growing meristem is achieved by signalling between stem cells and surrounding cells. We have here simulated the origin and maintenance of a defined stem cell domain at the tip of Arabidopsis shoot meristems, based on the assumption that meristems are self-organizing systems. The model comprises two coupled feedback regulated genetic systems that control stem cell behaviour. Using a minimal set of spatial parameters, the mathematical model allows to predict the generation, shape and size of the stem cell domain, and the underlying organizing centre. We use the model to explore the parameter space that allows stem cell maintenance, and to simulate the consequences of mutations, gene misexpression and cell ablations.

  10. Patterning processes in aggregates of Hydra cells visualized with the monoclonal antibody, TS19.

    Science.gov (United States)

    Sato, M; Bode, H R; Sawada, Y

    1990-10-01

    The monoclonal antibody, TS19, (Heimfeld et al., 1985), labels the apical surface of ectodermal epithelial cells of tentacles and lower peduncles in Hydra. To investigate the patterning process in a tissue whose original pattern was completely destroyed, the TS19 staining pattern was examined in developing aggregates of Hydra cells. Two types of aggregates were prepared. G-aggregates were made from tissue of the gastric portion of animals and RG-aggregates from gastric tissue allowed to regenerate for 24 hr before making aggregates. G-aggregates were initially TS19-negative, and later dim and uniformly TS19-positive. Thereafter, TS19 staining broke up into brightly stained and unstained regions. The brightly staining regions developed into head or foot structures. The TS19 pattern in RG-aggregates developed differently. Since the initial aggregates contained cells of regenerating tips, they started with TS19-positive cells as well as TS19-negative cells. The numbers of brightly staining TS19-positive cells increased with time. Some patches of these cells developed into head or foot structures, while others did not. These results and a simulation using a reaction-diffusion model suggest that the changes in activation levels affected the temporal changes in the pattern of TS19 staining, and that the de novo pattern formation in hydra can be explained in terms of a process involving activation and inhibition properties.

  11. Patterned carbon nanotubes as a new three-dimensional scaffold for mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Bitirim, Verda Ceylan [Department of Molecular Biology and Genetics, Bilkent University, 06800, Ankara (Turkey); Kucukayan-Dogu, Gokce [Institute of Engineering and Science, Material Science and Nanotechnology Graduate Program, Bilkent University, 06800, Ankara (Turkey); Bengu, Erman [Department of Chemistry, Bilkent University, 06800, Ankara (Turkey); Akcali, Kamil Can, E-mail: akcali@fen.bilkent.edu.tr [Department of Molecular Biology and Genetics, Bilkent University, 06800, Ankara (Turkey); Bilgen, Bilkent University Genetics and Biotechnology Research Center, 06800, Ankara (Turkey)

    2013-07-01

    We investigated the cellular adhesive features of mesenchymal stem cells (MSC) on non-coated and collagen coated patterned and vertically aligned carbon nanotube (CNT) structures mimicking the natural extra cellular matrix (ECM). Patterning was achieved using the elasto-capillary induced by water treatment on the CNT arrays. After confirmation with specific markers both at transcript and protein levels, MSCs from different passages were seeded on either collagen coated or non-coated patterned CNTs. Adhesion and growth of MSCs on the patterned CNT arrays were examined using scanning electron microscopy image analysis and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) assays. The highest MSC count was observed on the non-coated patterned CNTs at passage zero, while decreasing numbers of MSCs were found at the later passages. Similarly, MTT assay results also revealed a decrease in the viability of the MSCs for the later passages. Overall, the cell count and viability experiments indicated that MSCs were able to better attach to non-coated patterned CNTs compared to those coated with collagen. Therefore, the patterned CNT surfaces can be potentially used as a scaffold mimicking the ECM environment for MSC growth which presents an alternative approach to MSC-based transplantation therapy applications. - Highlights: • Synthesized vertically aligned CNTs were patterned to be used as scaffold. • The growth of mesenchymal stem cells was achieved on the patterned CNTs. • The cell number was counted higher on the patterned CNTs than collagen coated CNTs. • The MTT assay results revealed the cell viability on the patterned CNTs.

  12. Cell fate patterning during C. elegans vulval development

    OpenAIRE

    Hill, Russell J.; Sternberg, Paul W.

    1993-01-01

    Precursor cells of the vulva of the C. elegans hermaphrodite choose between two vulval cell fates (1° and 2°) and a non-vulval epidermal fate (3°) in response to three intercellular signals. An inductive signal produced by the anchor cell induces the vulval precursors to assume the 1° and 2° vulval fates. This inductive signal is an EGF-like growth factor encoded by the gene lin-3. An inhibitory signal mediated by lin-15, and which may originate from the surrounding epidermis, prevents the vu...

  13. Imaging Nuclear Morphology and Organization in Cleared Plant Tissues Treated with Cell Cycle Inhibitors.

    Science.gov (United States)

    de Souza Junior, José Dijair Antonino; de Sa, Maria Fatima Grossi; Engler, Gilbert; Engler, Janice de Almeida

    2016-01-01

    Synchronization of root cells through chemical treatment can generate a large number of cells blocked in specific cell cycle phases. In plants, this approach can be employed for cell suspension cultures and plant seedlings. To identify plant cells in the course of the cell cycle, especially during mitosis in meristematic tissues, chemical inhibitors can be used to block cell cycle progression. Herein, we present a simplified and easy-to-apply protocol to visualize mitotic figures, nuclei morphology, and organization in whole Arabidopsis root apexes. The procedure is based on tissue clearing, and fluorescent staining of nuclear DNA with DAPI. The protocol allows carrying out bulk analysis of nuclei and cell cycle phases in root cells and will be valuable to investigate mutants like overexpressing lines of genes disturbing the plant cell cycle.

  14. Innate recognition of apoptotic cells: novel apoptotic cell-associated molecular patterns revealed by crossreactivity of anti-LPS antibodies.

    Science.gov (United States)

    Tennant, I; Pound, J D; Marr, L A; Willems, J J L P; Petrova, S; Ford, C A; Paterson, M; Devitt, A; Gregory, C D

    2013-05-01

    Cells dying by apoptosis are normally cleared by phagocytes through mechanisms that can suppress inflammation and immunity. Molecules of the innate immune system, the pattern recognition receptors (PRRs), are able to interact not only with conserved structures on microbes (pathogen-associated molecular patterns, PAMPs) but also with ligands displayed by apoptotic cells. We reasoned that PRRs might therefore interact with structures on apoptotic cells - apoptotic cell-associated molecular patterns (ACAMPs) - that are analogous to PAMPs. Here we show that certain monoclonal antibodies raised against the prototypic PAMP, lipopolysaccharide (LPS), can crossreact with apoptotic cells. We demonstrate that one such antibody interacts with a constitutively expressed intracellular protein, laminin-binding protein, which translocates to the cell surface during apoptosis and can interact with cells expressing the prototypic PRR, mCD14 as well as with CD14-negative cells. Anti-LPS cross reactive epitopes on apoptotic cells colocalised with annexin V- and C1q-binding sites on vesicular regions of apoptotic cell surfaces and were released associated with apoptotic cell-derived microvesicles (MVs). These results confirm that apoptotic cells and microbes can interact with the immune system through common elements and suggest that anti-PAMP antibodies could be used strategically to characterise novel ACAMPs associated not only with apoptotic cells but also with derived MVs.

  15. PERIODIC STREAM LINES IN THE THREE-DIMENSIONAL SQUARE CELL PATTERN

    Institute of Scientific and Technical Information of China (English)

    李继彬; 段晚锁

    2001-01-01

    By using the theory of the generalized perturbed Hamiltonian systems, it is shown that there exist periodic stream lines in the three-dimensional square cell pattern of Rayleigh-Benard convection. The result means that our method enables this three dimensional flow pattern to be described in an unambiguous manner, and some experimental results of other authors can be explained.

  16. 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

    2015-10-22

    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.

  17. 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

    2015-01-01

    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 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. PMID:26489964

  18. Microtubules in Plant Cells: Strategies and Methods for Immunofluorescence, Transmission Electron Microscopy and Live Cell Imaging

    Science.gov (United States)

    Celler, Katherine; Fujita, Miki; Kawamura, Eiko; Ambrose, Chris; Herburger, Klaus; Wasteneys, Geoffrey O.

    2016-01-01

    Microtubules are required throughout plant development for a wide variety of processes, and different strategies have evolved to visualize and analyze them. This chapter provides specific methods that can be used to analyze microtubule organization and dynamic properties in plant systems and summarizes the advantages and limitations for each technique. We outline basic methods for preparing samples for immunofluorescence labelling, including an enzyme-based permeabilization method, and a freeze-shattering method, which generates microfractures in the cell wall to provide antibodies access to cells in cuticle-laden aerial organs such as leaves. We discuss current options for live cell imaging of MTs with fluorescently tagged proteins (FPs), and provide chemical fixation, high pressure freezing/freeze substitution, and post-fixation staining protocols for preserving MTs for transmission electron microscopy and tomography. PMID:26498784

  19. 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.

  20. Regional patterns and controlling factors in plant species composition and diversity in Canadian lowland coastal bogs and laggs

    Directory of Open Access Journals (Sweden)

    S.A. Howie

    2016-11-01

    Full Text Available Inventories of natural assemblages of plant species are critical when planning ecological restoration of bogs. However, little is known about the regional variation in plant communities at the margins (laggs of bogs, even though they are an integral element of raised bog ecosystems. Therefore, we investigated the regional patterns in the plant communities of bogs and laggs, and the factors that control them, for thirteen bogs in coastal British Columbia, Canada. Species richness was significantly higher in the bogs and laggs of the cooler, wetter Pacific Oceanic wetland region. Beta Diversity analyses showed that bogs in the Pacific Oceanic wetland region often shared species with their respective laggs, whereas half of the laggs in the warmer, drier Pacific Temperate wetland region had no species in common with the adjacent bogs and were thus more ecologically distinct from the bog. Primary climatic variables, such as mean annual precipitation, mean annual temperature and latitude, as well as climate-influenced variables, such as pH, peat depth, and Na+ concentrations were the main correlates of plant species composition in the studied bogs. Site-specific factors, particularly depth to water table, and fraction of inorganic material in peat samples, were as strongly related to lagg plant communities as climate, while hydrochemistry appeared to have less influence.

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

    OpenAIRE

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

    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. Modeling thalamocortical cell: impact of Ca2+ channel distribution and cell geometry on firing pattern

    Directory of Open Access Journals (Sweden)

    Reza Zomorrodi

    2008-12-01

    Full Text Available The influence of calcium channel distribution and geometry of the thalamocortical cell upon its tonic firing and the low threshold spike (LTS generation was studied in a 3-compartment model, which represents soma, proximal and distal dendrites as well as in multi-compartment model using the morphology of a real reconstructed neuron. Using an uniform distribution of Ca2+ channels, we determined the minimal number of low threshold voltage-activated calcium channels and their permeability required for the onset of LTS in response to a hyperpolarizing current pulse. In the 3-compartment model, we found that the channel distribution influences the firing pattern only in the range of 3% below the threshold value of total T-channel density. In the multi-compartmental model, the LTS could be generated by only 64% of unequally distributed T-channels compared to the minimal number of equally distributed T-channels. For a given channel density and injected current, the tonic firing frequency was found to be inversely proportional to the size of the cell. However, when the Ca2+ channel density was elevated in soma or proximal dendrites, then the amplitude of LTS response and burst spike frequencies were determined by the ratio of total to threshold number of T-channels in the cell for a specific geometry.

  3. Modeling Thalamocortical Cell: Impact of Ca2+ Channel Distribution and Cell Geometry on Firing Pattern

    Science.gov (United States)

    Zomorrodi, Reza; Kröger, Helmut; Timofeev, Igor

    2008-01-01

    The influence of calcium channel distribution and geometry of the thalamocortical cell upon its tonic firing and the low threshold spike (LTS) generation was studied in a 3-compartment model, which represents soma, proximal and distal dendrites as well as in multi-compartment model using the morphology of a real reconstructed neuron. Using an uniform distribution of Ca2+ channels, we determined the minimal number of low threshold voltage-activated calcium channels and their permeability required for the onset of LTS in response to a hyperpolarizing current pulse. In the 3-compartment model, we found that the channel distribution influences the firing pattern only in the range of 3% below the threshold value of total T-channel density. In the multi-compartmental model, the LTS could be generated by only 64% of unequally distributed T-channels compared to the minimal number of equally distributed T-channels. For a given channel density and injected current, the tonic firing frequency was found to be inversely proportional to the size of the cell. However, when the Ca2+ channel density was elevated in soma or proximal dendrites, then the amplitude of LTS response and burst spike frequencies were determined by the ratio of total to threshold number of T-channels in the cell for a specific geometry. PMID:19129908

  4. Creating two-dimensional patterned substrates for protein and cell confinement.

    Science.gov (United States)

    Johnson, Dawn M; LaFranzo, Natalie A; Maurer, Joshua A

    2011-01-01

    Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.(1) While microcontact printing can be employed to directly print a large number of molecules, including proteins,(2) DNA,(3) and silanes,(4) the formation of self-assembled monolayers (SAMs) from long chain alkane thiols on gold provides a simple way to confine proteins and cells to specific patterns containing adhesive and resistant regions. This confinement can be used to control cell morphology and is useful for examining a variety of questions in protein and cell biology. Here, we describe a general method for the creation of well-defined protein patterns for cellular studies.(5) This process involves three steps: the production of a patterned master using photolithography, the creation of a PDMS stamp, and microcontact printing of a gold-coated substrate. Once patterned, these cell culture substrates are capable of confining proteins and/or cells (primary cells or cell lines) to the pattern. The use of self-assembled monolayer chemistry allows for precise control over the patterned protein/cell adhesive regions and non-adhesive regions; this cannot be achieved using direct protein stamping. Hexadecanethiol, the long chain alkane thiol used in the microcontact printing step, produces a hydrophobic surface that readily adsorbs protein from solution. The glycol-terminated thiol, used for backfilling the non-printed regions of the substrate, creates a monolayer that is resistant to protein adsorption and therefore cell growth.(6) These thiol monomers produce highly structured monolayers that precisely define regions of the substrate that can support protein adsorption and cell growth. As a result, these substrates are useful for a wide variety of applications from the study of intercellular behavior(7) to the creation of microelectronics.(8) While other types of monolayer chemistry have been used for cell culture studies, including work from

  5. 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.

  6. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis.

    Science.gov (United States)

    Castanheira, Sónia; Mielnichuk, Natalia; Pérez-Martín, José

    2014-12-01

    Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue.

  7. Towards high-yield production of pharmaceutical proteins with plant cell suspension cultures.

    Science.gov (United States)

    Xu, Jianfeng; Ge, Xumeng; Dolan, Maureen C

    2011-01-01

    "Molecular farming" in plants with significant advantages in cost and safety is touted as a promising platform for the production of complex pharmaceutical proteins. While whole-plant produced biopharmaceuticals account for a significant portion of the preclinical and clinical pipeline, plant cell suspension culture, which integrates the merits of whole-plant systems with those of microbial fermentation, is emerging as a more compliant alternative "factory". However, low protein productivity remains a major obstacle that limits extensive commercialization of plant cell bioproduction platform. This review highlights the advantages and recent progress in plant cell culture technology and outlines viable strategies at both the biological and process engineering levels for advancing the economic feasibility of plant cell-based protein production. Approaches to overcome and solve the associated challenges of this culture system that include non-mammalian glycosylation and genetic instability will also be discussed.

  8. Predicting plant diversity patterns in Madagascar: understanding the effects of climate and land cover change in a biodiversity hotspot.

    Science.gov (United States)

    Brown, Kerry A; Parks, Katherine E; Bethell, Colin A; Johnson, Steig E; Mulligan, Mark

    2015-01-01

    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.

  9. 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.

  10. Micro-pattern formation of extracellular matrix (ECM) layers by atmospheric-pressure plasmas and cell culture on the patterned ECMs

    Science.gov (United States)

    Ando, Ayumi; Asano, Toshifumi; Urisu, Tsuneo; Hamaguchi, Satoshi

    2011-12-01

    A new patterning technique for the extracellular matrix (ECM) deposited on a Si substrate was developed with the use of a low-frequency atmospheric-pressure plasma and a metal stencil mask. The development of such a patterning technique for cell arrangement is a crucial step for the development of future cell chips. In this study, optimal process conditions for ECM patterning over the size of a typical single chip (about 1 cm2) were achieved and the obtained ECM patterns were directly observed by fluorescence labelling. It was also demonstrated that HEK293 cells (human embryo kidney cells) attach to and proliferate on the ECM layer patterned by this technique, arranging themselves on the Si substrate in the mask pattern.

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

    Science.gov (United States)

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

    1997-01-01

    Plant cell protoplasts derived from leaf tissue of two different tobacco species (Nicotiana tabacum., N. rustica L.) were exposed to short-term (sounding rocket experiments) and long-term (spacelab) microgravity environments in order to study both (electro) cell fusion and cell metabolism during early and later stages of tissue regeneration. The period of exposure to microgravity varied from 10 min (sounding rocket) to 10 d (space shuttle). The process of electro fusion of protoplasts was improved under conditions of microgravity: the time needed to establish close membrane contact between protoplasts (alignment time) was reduced (5 as compared to 15 s under 1 g) and numbers of fusion products between protoplasts of different specific density were increased by a factor of about 10. In addition, viability of fusion products, as shown by the ability to form callus, increased from about 60% to more than 90%. Regenerated fusion products obtained from both sounding-rocket and spacelab experiments showed a wide range of intermediate properties between the two parental plants. This was verified by isozyme analysis and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). In order to address potential metabolic responses, more general markers such as the overall energy state (ATP/ADP ratio), the redox charge of the diphosphopyridine nucleotide system (NADH/NAD ratio), and the pool size of fructose-2,6-bisphosphate (Fru 2,6 bisp), a regulator of the balance between glycolysis and gluconeogenesis, were determined. Responses of these parameters were different with regard to short-term and long-term exposure. Shortly after transition to reduced gravitation (sounding rocket) ratios of ATP/ADP exhibited strong fluctuation while the pool size of NAD decreased (indicating an increased NADH/NAD ratio) and that of Fru 2,6 bisp increased. As similar changes can be observed under stress conditions, this response is probably indicative of a metabolic stress

  13. Influence of the pattern shape on the photonic efficiency of front-side periodically patterned ultrathin crystalline silicon solar cells

    CERN Document Server

    Herman, Aline; Depauw, Valerie; Daif, Ounsi El; Deparis, Olivier

    2012-01-01

    Patterning the front side of an ultra-thin crystalline silicon (c Si) solar cell helps keeping the energy conversion efficiency high by compensating for the light absorption losses. A super-Gaussian mathematical expression was used in order to encompass a large variety of nanopattern shapes and to study their influence on the photonic performance. We prove that the enhancement in the maximum achievable photo-current is due to both impedance matching condition at short wavelengths and to the wave nature of light at longer wavelengths. We show that the optimal mathematical shape and parameters of the pattern depend on the c Si thickness. An optimal shape comes with a broad optimal parameter zone where fabricating errors would have much less influence on the efficiency. We prove that cylinders are not the best suited shape. To compare our model with a real slab, we fabricated a nanopatterned c Si slab via Nano Imprint Lithography.

  14. Light-Addressable Electrodeposition of Magnetically-Guided Cells Encapsulated in Alginate Hydrogels for Three-Dimensional Cell Patterning

    Directory of Open Access Journals (Sweden)

    Shih-Hao Huang

    2014-11-01

    Full Text Available This paper describes a light-addressable electrolytic system used to perform an electrodeposition of magnetically-guided cells encapsulated in alginate hydrogels using a digital micromirror device (DMD for three-dimensional cell patterning. In this system, the magnetically-labeled cells were first manipulated into a specific arrangement by changing the orientation of the magnetic field, and then a patterned light illumination was projected onto a photoconductive substrate serving as a photo-anode to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, we first successfully produced cell-encapsulated multilayer alginate hydrogels with different shapes and sizes in each layer via performing multiplexed micropatterning. By combining the magnetically-labeled cells, light-addressable electrodeposition, and orientation of the magnetic fields, we have successfully demonstrated to fabricate two layers of the cell-encapsulated alginate hydrogels, where cells in each layer can be manipulated into cross-directional arrangements that mimic natural tissue. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into three-dimensional cell patterning and could have a wide range of biological applications in tissue engineering, toxicology, and drug discovery.

  15. Involvement of plant stem cells or stem cell-like cells in dedifferentiation

    Directory of Open Access Journals (Sweden)

    Fangwei eJiang

    2015-11-01

    Full Text Available Dedifferentiation is the transformation of cells from a given differentiated state to a less differentiated or stem cell-like state. Stem cell-related genes play important roles in dedifferentiation, which exhibits similar histone modification and DNA methylation features to stem cell maintenance. Hence, stem cell-related factors possibly synergistically function to provide a specific niche beneficial to dedifferentiation. During callus formation in Arabidopsis petioles, cells adjacent to procambium cells (stem cell-like cells are dedifferentiated and survive more easily than other cell types. This finding indicates that stem cells or stem cell-like cells may influence the dedifferentiating niche. In this paper, we provide a brief overview of stem cell maintenance and dedifferentiation regulation. We also summarize current knowledge of genetic and epigenetic mechanisms underlying the balance between differentiation and dedifferentiation. Furthermore, we discuss the correlation of stem cells or stem cell-like cells with dedifferentiation.

  16. Distinguishing Pattern Formation Phenotypes: Applying Minkowski Functionals to Cell Biology Systems

    Science.gov (United States)

    Rericha, Erin; Guven, Can; Parent, Carole; Losert, Wolfgang

    2011-03-01

    Spatial Clustering of proteins within cells or cells themselves frequently occur in cell biology systems. However quantifying the underlying order and determining the regulators of these cluster patterns have proved difficult due to the inherent high noise levels in the systems. For instance the patterns formed by wild type and cyclic-AMP regulatory mutant Dictyostelium cells are visually distinctive, yet the large error bars in measurements of the fractal number, area, Euler number, eccentricity, and wavelength making it difficult to quantitatively distinguish between the patterns. We apply a spatial analysis technique based on Minkowski functionals and develop metrics which clearly separate wild type and mutant cell lines into distinct categories. Having such a metric facilitated the development of a computational model for cellular aggregation and its regulators. Supported by NIH-NGHS Nanotechnology (R01GM085574) and the Burroughs Wellcome Fund.

  17. DNA methyltransferase 1 and DNA methylation patterning contribute to germinal center B-cell differentiation

    DEFF Research Database (Denmark)

    Shaknovich, Rita; Cerchietti, Leandro; Tsikitas, Lucas;

    2011-01-01

    The phenotype of germinal center (GC) B cells includes the unique ability to tolerate rapid proliferation and the mutagenic actions of activation induced cytosine deaminase (AICDA). Given the importance of epigenetic patterning in determining cellular phenotypes, we examined DNA methylation and t......, the GC B cells of Dnmt1 hypomorphic animals showed evidence of increased DNA damage, suggesting dual roles for DNMT1 in DNA methylation and double strand DNA break repair.......The phenotype of germinal center (GC) B cells includes the unique ability to tolerate rapid proliferation and the mutagenic actions of activation induced cytosine deaminase (AICDA). Given the importance of epigenetic patterning in determining cellular phenotypes, we examined DNA methylation...... and the role of DNA methyltransferases in the formation of GCs. DNA methylation profiling revealed a marked shift in DNA methylation patterning in GC B cells versus resting/naive B cells. This shift included significant differential methylation of 235 genes, with concordant inverse changes in gene expression...

  18. Tissue-specific, development-dependent phenolic compounds accumulation profile and gene expression pattern in tea plant [Camellia sinensis].

    Science.gov (United States)

    Jiang, Xiaolan; Liu, Yajun; Li, Weiwei; Zhao, Lei; Meng, Fei; Wang, Yunsheng; Tan, Huarong; Yang, Hua; Wei, Chaoling; Wan, Xiaochun; Gao, Liping; Xia, Tao

    2013-01-01

    Phenolic compounds in tea plant [Camellia sinensis (L.)] play a crucial role in dominating tea flavor and possess a number of key pharmacological benefits on human health. The present research aimed to study the profile of tissue-specific, development-dependent accumulation pattern of phenolic compounds in tea plant. A total of 50 phenolic compounds were identified qualitatively using liquid chromatography in tandem mass spectrometry technology. Of which 29 phenolic compounds were quantified based on their fragmentation behaviors. Most of the phenolic compounds were higher in the younger leaves than that in the stem and root, whereas the total amount of proanthocyanidins were unexpectedly higher in the root. The expression patterns of 63 structural and regulator genes involved in the shikimic acid, phenylpropanoid, and flavonoid pathways were analyzed by quantitative real-time polymerase chain reaction and cluster analysis. Based on the similarity of their expression patterns, the genes were classified into two main groups: C1 and C2; and the genes in group C1 had high relative expression level in the root or low in the bud and leaves. The expression patterns of genes in C2-2-1 and C2-2-2-1 groups were probably responsible for the development-dependent accumulation of phenolic compounds in the leaves. Enzymatic analysis suggested that the accumulation of catechins was influenced simultaneously by catabolism and anabolism. Further research is recommended to know the expression patterns of various genes and the reason for the variation in contents of different compounds in different growth stages and also in different organs.

  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. Regulation of plant cells, cell walls and development by mechanical signals

    Energy Technology Data Exchange (ETDEWEB)

    Meyerowitz, Elliot M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-06-14

    The overall goal of the revised scope of work for the final year of funding was to characterize cell wall biosynthesis in developing cotyledons and in the shoot apical meristem of Arabidopsis thaliana, as a way of learning about developmental control of cell wall biosynthesis in plants, and interactions between cell wall biosynthesis and the microtubule cytoskeleton. The proposed work had two parts – to look at the effect of mutation in the SPIRAL2 gene on microtubule organization and reorganization, and to thoroughly characterize the glycosyltransferase genes expressed in shoot apical meristems by RNA-seq experiments, by in situ hybridization of the RNAs expressed in the meristem, and by antibody staining of the products of the glycosyltransferases in meristems. Both parts were completed; the spiral2 mutant was found to speed microtubule reorientation after ablation of adjacent cells, supporting our hypothesis that reorganization correlates with microtubule severing, the rate of which is increased by the mutation. The glycosyltransferase characterization was completed and published as Yang et al. (2016). Among the new things learned was that primary cell wall biosynthesis is strongly controlled both by cell type, and by stage of cell cycle, implying not only that different, even adjacent, cells can have different sugar linkages in their (nonshared) walls, but also that a surprisingly large proportion of glycosyltransferases is regulated in the cell cycle, and therefore that the cell cycle regulates wall maturation to a degree previously unrecognized.

  1. Systematic variation in gene expression patterns in human cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Douglas T.; Scherf, Uwe; Eisen, Michael B.; Perou, Charles M.; Rees, Christian; Spellman, Paul; Iyer, Vishwanath; Jeffrey, Stefanie S.; Van de Rijn, Matt; Waltham, Mark; Pergamenschikov, Alexander; Lee, Jeffrey C.F.; Lashkari, Deval; Shalon, Dari; Myers, Timothy G.; Weinstein, John N.; Botstein, David; Brown, Patrick O.

    2000-01-01

    We used cDNA micro arrays to explore the variation in expression of approximately 8,000 unique genes among the 60 cell lines used in the National Cancer Institute s screen for anti-cancer drugs. Classification of the cell lines based solely on the observed patterns of gene expression revealed a correspondence to the ostensible origins of the tumors from which the cell lines were derived. The consistent relationship between the gene expression patterns and the tissue of origin allowed us to recognize outliers whose previous classification appeared incorrect. Specific features of the gene expression patterns appeared to be related to physiological properties of the cell lines, such as their doubling time in culture, drug metabolism or the interferon response. Comparison of gene expression patterns in the cell lines to those observed in normal breast tissue or in breast tumor specimens revealed features of the expression patterns in the tumors that had recognizable counterparts in specific cell lines, reflecting the tumor, stromal and inflammatory components of the tumor tissue. These results provided a novel molecular characterization of this important group of human cell lines and their relationships to tumors in vivo.

  2. Gelatin-based laser direct-write technique for the precise spatial patterning of cells.

    Science.gov (United States)

    Schiele, Nathan R; Chrisey, Douglas B; Corr, David T

    2011-03-01

    Laser direct-writing provides a method to pattern living cells in vitro, to study various cell-cell interactions, and to build cellular constructs. However, the materials typically used may limit its long-term application. By utilizing gelatin coatings on the print ribbon and growth surface, we developed a new approach for laser cell printing that overcomes the limitations of Matrigel™. Gelatin is free of growth factors and extraneous matrix components that may interfere with cellular processes under investigation. Gelatin-based laser direct-write was able to successfully pattern human dermal fibroblasts with high post-transfer viability (91% ± 3%) and no observed double-strand DNA damage. As seen with atomic force microscopy, gelatin offers a unique benefit in that it is present temporarily to allow cell transfer, but melts and is removed with incubation to reveal the desired application-specific growth surface. This provides unobstructed cellular growth after printing. Monitoring cell location after transfer, we show that melting and removal of gelatin does not affect cellular placement; cells maintained registry within 5.6 ± 2.5 μm to the initial pattern. This study demonstrates the effectiveness of gelatin in laser direct-writing to create spatially precise cell patterns with the potential for applications in tissue engineering, stem cell, and cancer research.

  3. Membrane associated qualitative differences in cell ultrastructure of chemically and high pressure cryofixed plant cells.

    Science.gov (United States)

    Zechmann, Bernd; Müller, Maria; Zellnig, Günther

    2007-06-01

    Membrane contrast can sometimes be poor in biological samples after high pressure freezing (HPF) and freeze substitution (FS). The addition of water to the FS-medium has been shown to improve membrane contrast in animal tissue and yeast. In the present study we tested the effects of 1% and 5% water added to the FS-medium (2% osmium with 0.2% uranyl acetate in anhydrous acetone) on the quality and visibility of membranes in high pressure frozen leaf samples of Cucurbita pepo L. plants and compared them to chemically fixed cells (3% glutaraldehyde post-fixed with 1% osmium tetroxide). The addition of water to the FS-medium drastically decreased the amounts of well preserved cells and did not significantly improve the quality nor visibility of membranes. In samples that were freeze substituted in FS-media containing 1% and 5% water the width of thylakoid membranes was found to be significantly increased of about 20% and the perinuclear space was up to 76% wider in comparison to what was found in samples which were freeze substituted without water. No differences were found in the thickness of membranes between chemically and cryofixed cells that were freeze substituted in the FS-medium without water. Nevertheless, in chemically fixed cells the intrathylakoidal space was about 120% wider than in cryofixed cells that were freeze substituted with or without water. The present results demonstrate that the addition of water to the FS-medium does not improve membrane contrast but changes the width of thylakoid membranes and the perinuclear space in the present plant material. The addition of water to the FS-medium is therefore not as essential for improved membrane contrast in the investigated plant samples as it was observed in cells of animal tissues and yeast cells.

  4. 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

  5. The isolation of spatial patterning modes in a mathematical model of juxtacrine cell signalling.

    Science.gov (United States)

    O'Dea, R D; King, J R

    2013-06-01

    Juxtacrine signalling mechanisms are known to be crucial in tissue and organ development, leading to spatial patterns in gene expression. We investigate the patterning behaviour of a discrete model of juxtacrine cell signalling due to Owen & Sherratt (1998, Mathematical modelling of juxtacrine cell signalling. Math. Biosci., 153, 125-150) in which ligand molecules, unoccupied receptors and bound ligand-receptor complexes are modelled. Feedback between the ligand and receptor production and the level of bound receptors is incorporated. By isolating two parameters associated with the feedback strength and employing numerical simulation, linear stability and bifurcation analysis, the pattern-forming behaviour of the model is analysed under regimes corresponding to lateral inhibition and induction. Linear analysis of this model fails to capture the patterning behaviour exhibited in numerical simulations. Via bifurcation analysis, we show that since the majority of periodic patterns fold subcritically from the homogeneous steady state, a wide variety of stable patterns exists at a given parameter set, providing an explanation for this failure. The dominant pattern is isolated via numerical simulation. Additionally, by sampling patterns of non-integer wavelength on a discrete mesh, we highlight a disparity between the continuous and discrete representations of signalling mechanisms: in the continuous case, patterns of arbitrary wavelength are possible, while sampling such patterns on a discrete mesh leads to longer wavelength harmonics being selected where the wavelength is rational; in the irrational case, the resulting aperiodic patterns exhibit 'local periodicity', being constructed from distorted stable shorter wavelength patterns. This feature is consistent with experimentally observed patterns, which typically display approximate short-range periodicity with defects.

  6. Multiple host-cell recombination pathways act in Agrobacterium-mediated transformation of plant cells.

    Science.gov (United States)

    Mestiri, Imen; Norre, Frédéric; Gallego, Maria E; White, Charles I

    2014-02-01

    Using floral-dip, tumorigenesis and root callus transformation assays of both germline and somatic cells, we present here results implicating the four major non-homologous and homologous recombination pathways in Agrobacterium-mediated transformation of Arabidopsis thaliana. All four single mutant lines showed similar mild reductions in transformability, but knocking out three of four pathways severely compromised Agrobacterium-mediated transformation. Although integration of T-DNA into the plant genome is severely compromised in the absence of known DNA double-strand break repair pathways, it does still occur, suggesting the existence of other pathways involved in T-DNA integration. Our results highlight the functional redundancy of the four major plant recombination pathways in transformation, and provide an explanation for the lack of strong effects observed in previous studies on the roles of plant recombination functions in transformation.

  7. 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.

  8. The hypersensitive induced reaction and leucine-rich repeat proteins regulate plant cell death associated with disease and plant immunity.

    Science.gov (United States)

    Choi, Hyong Woo; Kim, Young Jin; Hwang, Byung Kook

    2011-01-01

    Pathogen-induced programmed cell death (PCD) is intimately linked with disease resistance and susceptibility. However, the molecular components regulating PCD, including hypersensitive and susceptible cell death, are largely unknown in plants. In this study, we show that pathogen-induced Capsicum annuum hypersensitive induced reaction 1 (CaHIR1) and leucine-rich repeat 1 (CaLRR1) function as distinct plant PCD regulators in pepper plants during Xanthomonas campestris pv. vesicatoria infection. Confocal microscopy and protein gel blot analyses revealed that CaLRR1 and CaHIR1 localize to the extracellular matrix and plasma membrane (PM), respectively. Bimolecular fluorescent complementation and coimmunoprecipitation assays showed that the extracellular CaLRR1 specifically binds to the PM-located CaHIR1 in pepper leaves. Overexpression of CaHIR1 triggered pathogen-independent cell death in pepper and Nicotiana benthamiana plants but not in yeast cells. Virus-induced gene silencing (VIGS) of CaLRR1 and CaHIR1 distinctly strengthened and compromised hypersensitive and susceptible cell death in pepper plants, respectively. Endogenous salicylic acid levels and pathogenesis-related gene transcripts were elevated in CaHIR1-silenced plants. VIGS of NbLRR1 and NbHIR1, the N. benthamiana orthologs of CaLRR1 and CaHIR1, regulated Bax- and avrPto-/Pto-induced PCD. Taken together, these results suggest that leucine-rich repeat and hypersensitive induced reaction proteins may act as cell-death regulators associated with plant immunity and disease.

  9. Patterned three-dimensional encapsulation of embryonic stem cells using dielectrophoresis and stereolithography.

    Science.gov (United States)

    Bajaj, Piyush; Marchwiany, Daniel; Duarte, Carlos; Bashir, Rashid

    2013-03-01

    Controlling the assembly of cells in three dimensions is very important for engineering functional tissues, drug screening, probing cell-cell/cell-matrix interactions, and studying the emergent behavior of cellular systems. Although the current methods of cell encapsulation in hydrogels can distribute them in three dimensions, these methods typically lack spatial control of multi-cellular organization and do not allow for the possibility of cell-cell contacts as seen for the native tissue. Here, we report the integration of dielectrophoresis (DEP) with stereolithography (SL) apparatus for the spatial patterning of cells on custom made gold micro-electrodes. Afterwards, they are encapsulated in poly (ethylene glycol) diacrylate (PEGDA) hydrogels of different stiffnesses. This technique can mimic the in vivo microscale tissue architecture, where the cells have a high degree of three dimensional (3D) spatial control. As a proof of concept, we show the patterning and encapsulation of mouse embryonic stem cells (mESCs) and C2C12 skeletal muscle myoblasts. mESCs show high viability in both the DEP (91.79% ± 1.4%) and the no DEP (94.27% ± 0.5%) hydrogel samples. Furthermore, we also show the patterning of mouse embryoid bodies (mEBs) and C2C12 spheroids in the hydrogels, and verify their viability. This robust and flexible in vitro platform can enable various applications in stem cell differentiation and tissue engineering by mimicking elements of the native 3D in vivo cellular micro-environment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-02

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

  11. Ubiquitin chain topology and its impact on plant cell signalling

    Directory of Open Access Journals (Sweden)

    Charlotte Kirsten Walsh

    2014-04-01

    Full Text Available Ubiquitin is a peptide modifier able to form polymers of varying length and linkage as part of a powerful signalling system. Perhaps the best-known aspect of this protein’s function is as the driver of targeted protein degradation through the Ubiquitin Proteasome System (UPS. Through the formation of lysine 48-linked polyubiquitin chains, it is able to direct the degradation of tagged proteins by the 26S proteasome, indirectly controlling many processes within the cell. However, recent research has indicated that ubiquitin performs a multitude of other roles within the cell beyond protein degradation. It is able to form 6 other ‘atypical’ linkages though lysine residues at positions 6, 11, 27, 29, 33 and 63. These atypical chains perform a range of diverse functions, including the regulation of iron uptake in response to perceived deficiency, repair of double stranded breaks in the DNA, and regulation of the auxin response through the non-proteasomal degradation of auxin efflux carrier protein PIN1. This review explores the role ubiquitin chain topology plays in plant cellular function. We aim to highlight the importance of these varying functions and the future challenges to be encountered within this field.

  12. 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.

  13. Im"plant"ing of Mammalian Glycosyltransferase Gene into Plant Suspension-Cultured Cells Using Agrobacterium-Mediated Transformation.

    Science.gov (United States)

    Kajiura, Hiroyuki; Fujiyama, Kazuhito

    2015-01-01

    Enzymatic activity assay of exogenous glycosyltransferase (GT) and glycosylhydrolase (GH) expressed in plants is an important analysis for determination of the expression of the gene of interest. However, generations and establishment of in planta transgenic lines are time-consuming. Furthermore, the expression levels and the activities of the exogenous GTs and GHs are quite low and weak, the radiolabeled donor substrate had to be used to analyze the enzymatic activity. Here, we describe a protocol for the generation of transgenic plants using suspension-cultured cells and a high sensitive assay for GT, especially β1,4-galactosyltransferase, using microsomal fraction from plant cells and fluorescent-labeled sugar chains as an acceptor substrate. This method enables less-time-consuming preparation of stable transgenic plants, non-radiolabeled, high-throughput detail analysis which includes mass spectrometric analysis and exo-glycosidase digestions.

  14. Patterning Cells on Optically Transparent Indium Tin Oxide Electrodes

    OpenAIRE

    Shah, Sunny; Revzin, Alexander

    2007-01-01

    The ability to exercise precise spatial and temporal control over cell-surface interactions is an important prerequisite to the assembly of multi-cellular constructs serving as in vitro mimics of native tissues. In this study, photolithography and wet etching techniques were used to fabricate individually addressable indium tin oxide (ITO) electrodes on glass substrates. The glass substrates containing ITO microelectrodes were modified with poly(ethylene glycol) (PEG) silane to make them pr...

  15. Abiotic drivers and plant traits explain landscape-scale patterns in soil microbial communities.