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1. Agrobacterium-mediated gene delivery and transient expression in the red macroalga Chondrus crispus

Author

John H. F. Bothwell, Christine A. Maggs, Anusha Devi Ramessur, Siew-Moi Phang, and Sook Yee Gan

Subjects
0301 basic medicine, Acetosyringone, Reporter gene, biology, Agrobacterium, fungi, Plant Science, Aquatic Science, Chondrus, biology.organism_classification, Cell biology, 03 medical and health sciences, chemistry.chemical_compound, Transformation (genetics), 030104 developmental biology, chemistry, Chondrus crispus, Green algae, Ecology, Evolution, Behavior and Systematics, Transformation efficiency
Abstract

Molecular resources and transgenic studies in red algae are lagging behind those for green algae. The Agrobacterium-mediated gene-transfer method routinely used in plant transformation has not been fully utilised in the red algae, which, as an important source of phycocolloids, warrant more studies. In this regard, a stepwise methodology was developed for Agrobacterium-mediated transformation of the carrageenophyte Chondrus crispus using pCAMBIA 1301 and a construct featuring a codon-optimized beta-glucuronidase (GUS) reporter gene driven by the endogenous Chondrus actin promoter. The effects of several factors on transformation efficiency were investigated. An intimate association of Chondrus and bacterial cells was observed using scanning electron microscopy. GUS transient expression within Chondrus cortical and medullary cells with both expression cassettes testified to the amenability of Chondrus to Agrobacterium-mediated transformation. Darker staining, indicative of higher GUS activity, was observed with the Chondrus-specific construct, suggesting its superiority over the pCAMBIA 1301. Presence of acetosyringone, the wounding method and the type of co-cultivation medium significantly affected the transformation outcome and efficiency. The Agrobacterium-mediated transient expression presented here constitutes a first step towards tailoring a transformation strategy for Chondrus, which can serve to facilitate further transgenic studies in this important red alga.

Published
2018
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3. Insights into the evolution of multicellularity from the sea lettuce genome

Author

Rachel Clewes, Fatima Foflonker, Olivier De Clerck, Dominique Van Der Straeten, Zoë A. Popper, Noe Fernandez-Pozo, John H. F. Bothwell, Kenny A. Bogaert, Lieven Sterck, Xiaojie Liu, Andrea Del Cortona, Per K.I. Wilhelmsson, Frederik Leliaert, Sofie D'hondt, John A. Raven, Marc Hanikenne, Juliet C. Coates, Linda Lattermann, Claire M. M. Gachon, Jonas Blomme, Debashish Bhattacharya, Stefan A. Rensing, Lisa Vanderstraeten, Michiel Kwantes, Thomas Wichard, Michiel Van Bel, Emmelien Vancaester, Christine A. Maggs, Eylem Aydogdu, Jens Boesger, Bénédicte Charrier, Shu-Min Kao, Yves Van de Peer, Assaf Vardi, Klaas Vandepoele, and Gianmaria Califano

Subjects
0106 biological sciences, 0301 basic medicine, Lineage (evolution), Dimethylsulfoniopropionate, 01 natural sciences, Genome, General Biochemistry, Genetics and Molecular Biology, Ulva, 03 medical and health sciences, chemistry.chemical_compound, Algae, 14. Life underwater, Life History Traits, biology, Ulvophyceae, fungi, Chromosome Mapping, 15. Life on land, biology.organism_classification, Biological Evolution, Multicellular organism, 030104 developmental biology, chemistry, Evolutionary biology, Multigene Family, Horizontal gene transfer, General Agricultural and Biological Sciences, Sea lettuce, Developmental Biology, 010606 plant biology & botany
Abstract

© 2018 Elsevier Ltd We report here the 98.5 Mbp haploid genome (12,924 protein coding genes) of Ulva mutabilis, a ubiquitous and iconic representative of the Ulvophyceae or green seaweeds. Ulva's rapid and abundant growth makes it a key contributor to coastal biogeochemical cycles; its role in marine sulfur cycles is particularly important because it produces high levels of dimethylsulfoniopropionate (DMSP), the main precursor of volatile dimethyl sulfide (DMS). Rapid growth makes Ulva attractive biomass feedstock but also increasingly a driver of nuisance “green tides.” Ulvophytes are key to understanding the evolution of multicellularity in the green lineage, and Ulva morphogenesis is dependent on bacterial signals, making it an important species with which to study cross-kingdom communication. Our sequenced genome informs these aspects of ulvophyte cell biology, physiology, and ecology. Gene family expansions associated with multicellularity are distinct from those of freshwater algae. Candidate genes, including some that arose following horizontal gene transfer from chromalveolates, are present for the transport and metabolism of DMSP. The Ulva genome offers, therefore, new opportunities to understand coastal and marine ecosystems and the fundamental evolution of the green lineage. De Clerck et al. present the first genome sequence of a green seaweed, a dominant group of primary producers in coastal environments. The Ulva genome informs on an independent acquisition of multicellularity, sheds light on adaptations to life in intertidal habitats, and identifies candidate genes involved in DMSP biosynthesis and conversion to DMS.

Published
2018
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4. Between-taxon matching of common and rare species richness patterns

Author

John H. F. Bothwell, Carl J. Reddin, and Jack J. Lennon

Subjects
Global and Planetary Change, Taxon, Ecology, Common species, Rare species, Species distribution, Species diversity, Species richness, Body size and species richness, Intertidal ecology, Biology, Ecology, Evolution, Behavior and Systematics
Abstract

Aim Our primary aim is to understand how assemblages of rare (restricted range) and common (widespread) species are correlated with each other among different taxa. We tested the proposition that marine species richness patterns of rare and common species differ, both within a taxon in their contribution to the richness pattern of the full assemblage and among taxa in the strength of their correlations with each other. Location The UK intertidal zone. Methods We used high-resolution marine datasets for UK intertidal macroalgae, molluscs and crustaceans each with more than 400 species. We estimated the relative contribution of rare and common species, treating rarity and commonness as a continuous spectrum, to spatial patterns in richness using spatial cross-correlations. Correlation strength and significance was estimated both within and between taxa. Results Common species drove richness patterns within taxa, but rare species contributed more when species were placed on an equal footing via scaling by binomial variance. Between taxa, relatively small sub-assemblages (fewer than 60 species) of common species produced the maximum correlation with each other, regardless of taxon pairing. Cross-correlations between rare species were generally weak, with maximum correlation occurring between small sub-assemblages in only one case. Cross-correlations between common and rare species of different taxa were consistently weak or absent. Main conclusions Common species in the three marine assemblages were congruent in their richness patterns, but rare species were generally not. The contrast between the stronger correlations among common species and the weak or absent correlations among rare species indicates a decoupling of the processes driving common and rare species richness patterns. The internal structure of richness patterns of these marine taxa is similar to that observed for terrestrial taxa.

Published
2015
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5. An integrated process for the extraction of fuel and chemicals from marine macroalgal biomass

Author

Vishal Gupta, Bhavanath Jha, Arvind M. Lali, Nitin Trivedi, Ravi S. Baghel, John H. F. Bothwell, and C. R. K. Reddy

Subjects
0106 biological sciences, Biomass to liquid, Biomass, 010501 environmental sciences, Raw material, complex mixtures, 01 natural sciences, Article, chemistry.chemical_compound, Chlorophyta, Polysaccharides, 010608 biotechnology, Enzymatic hydrolysis, Botany, Ethanol fuel, Cellulose, 0105 earth and related environmental sciences, Minerals, Multidisciplinary, Plant Extracts, Hydrolysis, Extraction (chemistry), food and beverages, Seaweed, Pulp and paper industry, Lipids, chemistry, Biofuels, Fermentation
Abstract

We describe an integrated process that can be applied to biomass of the green seaweed, Ulva fasciata, to allow the sequential recovery of four economically important fractions; mineral rich liquid extract (MRLE), lipid, ulvan and cellulose. The main benefits of our process are: a) its simplicity and b) the consistent yields obtained from the residual biomass after each successive extraction step. For example, dry Ulva biomass yields ~26% of its starting mass as MRLE, ~3% as lipid, ~25% as ulvan and ~11% as cellulose, with the enzymatic hydrolysis and fermentation of the final cellulose fraction under optimized conditions producing ethanol at a competitive 0.45 g/g reducing sugar. These yields are comparable to those obtained by direct processing of the individual components from primary biomass. We propose that this integration of ethanol production and chemical feedstock recovery from macroalgal biomass could substantially enhance the sustainability of marine biomass use.

Published
2016
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6. An introduction to biological nuclear magnetic resonance spectroscopy

Author

John H. F. Bothwell and Julian L. Griffin

Subjects
Proteomics, Carbon Isotopes, Magnetic Resonance Spectroscopy, Materials science, Phosphorus Isotopes, Fluorine-19 NMR, Nuclear magnetic resonance crystallography, Nuclear magnetic resonance spectroscopy, Hydrogen-Ion Concentration, Carbon-13 NMR, General Biochemistry, Genetics and Molecular Biology, Chemical physics, Proton NMR, Animals, Transverse relaxation-optimized spectroscopy, Hyperpolarization (physics), General Agricultural and Biological Sciences, Two-dimensional nuclear magnetic resonance spectroscopy
Abstract

Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical techniques available to biology. This review is an introduction to the potential of this method and is aimed at readers who have little or no experience in acquiring or analyzing NMR spectra. We focus on spectroscopic applications of the magnetic resonance effect, rather than imaging ones, and explain how various aspects of the NMR phenomenon make it a versatile tool with which to address a number of biological problems. Using detailed examples, we discuss the use of (1) H NMR spectroscopy in mixture analysis and metabolomics, the use of (13) C NMR spectroscopy in tracking isotopomers and determining the flux through metabolic pathways ('fluxomics') and the use of (31) P NMR spectroscopy in monitoring ATP generation and intracellular pH homeotasis in vivo. Further examples demonstrate how NMR spectroscopy can be used to probe the physical environment of a cell by measuring diffusion and the tumbling rates of individual metabolites and how it can determine macromolecular structures by measuring the bonds and distances which separate individual atoms. We finish by outlining some of the key challenges which remain in NMR spectroscopy and we highlight how recent advances-such as increased magnet field strengths, cryogenic cooling, microprobes and hyperpolarisation-are opening new avenues for today's biological NMR spectroscopists.

Published
2010
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7. Two voltage‐dependent calcium channels co‐exist in the apical plasma membrane of Arabidopsis thaliana root hairs

Author

Vadim Demidchik, Henk Miedema, Julia M. Davies, Colin Brownlee, John H. F. Bothwell, Anne-Aliénor Véry, Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier (UM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
0106 biological sciences, Arabidopsis thaliana, Physiology, Arabidopsis, channel, Gadolinium, nadph, Plant Science, permeable channels, Root hair elongation, Cation Channel Blocker, Plant Roots, 01 natural sciences, Membrane Potentials, depolarization, Gene Expression Regulation, Plant, MESH: Calcium: metabolism, membrane, Membrane potential, 0303 health sciences, MESH: Electrophysiology, Voltage-dependent calcium channel, Chemistry, oxidase, ion channels, Depolarization, abscisic-acid, anion, cation channels, Electrophysiology, medicago-sativa, ca2+ channels, MESH: Cell Membrane: metabolism, psychological phenomena and processes, root hair, Root hair, behavioral disciplines and activities, 03 medical and health sciences, Botany, MESH: Membrane Potentials, MESH: Calcium Channels: genetics,metabolism, MESH: Plant Roots: cytology,metabolism, stomatal guard-cells, plasma, Ion channel, 030304 developmental biology, calcium, MESH: Arabidopsis: metabolism, Cell Membrane, Conductance, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, anion channels, MESH: Gene Expression Regulation, Plant: physiology, k+ channels, Biophysics, Calcium Channels, MESH: Gadolinium, 010606 plant biology & botany
Abstract

English Article NEW PHYTOL 325ED; Calcium (Ca2+)-permeable plasma membrane ion channels are critical to root hair elongation and signalling. Arabidopsis thaliana root hair plasma membrane contains a hyperpolarization-activated Ca2+ channel (HACC) conductance. Here, the co-residence of HACC with a depolarization-activated Ca2+ channel (DACC) conductance has been investigated. Whole-cell patch-clamping of apical plasma membrane has been used to study Ca2+ conductances and reveal the negative slope conductance typical of DACCs. Specific voltage protocols, Ba(2+)-permeation and inhibition by the cation channel blocker Gd3+ have been used to identify the DACC conductance. The Gd3+ sensitive DACC conductance was identified in only a minority of cells. DACC activity was quickly masked by the development of the HACC conductance. However, in the period between the disappearance of the negative slope conductance and the predominance of HACC, DACC activity could still be detected. A DACC conductance coexists with HACC in the root hair apical plasma membrane and could provide Ca2+ influx over a wide voltage range, consistent with a role in signalling.

Published
2008
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8. Ca2+ signals coordinate zygotic polarization and cell cycle progression in the brown algaFucus serratus

Author

Martin J. Genner, J Kisielewska, John H. F. Bothwell, Martin R. McAinsh, and Colin Brownlee

Subjects
Zygote, biology, Fucus serratus, Cell Cycle, Cell, Cell Polarity, Phaeophyta, biology.organism_classification, Models, Biological, Yeast, Cell biology, Brown algae, medicine.anatomical_structure, Human fertilization, Botany, medicine, Animals, Calcium Signaling, Molecular Biology, Intracellular, Actin, Developmental Biology
Abstract

Zygotes of the fucoid brown algae provide excellent models for addressing fundamental questions about zygotic symmetry breaking. Although the acquisition of polarity is tightly coordinated with the timing and orientation of the first asymmetric division-with zygotes having to pass through a G1/S-phase checkpoint before the polarization axis can be fixed-the mechanisms behind the interdependence of polarization and cell cycle progression remain unclear. In this study, we combine in vivo Ca2+ imaging, single cell monitoring of S-phase progression and multivariate analysis of high-throughput intracellular Ca2+ buffer loading to demonstrate that Ca2+ signals coordinate polarization and cell cycle progression in the Fucus serratus zygote. Consistent with earlier studies on this organism, and in contrast to animal models, we observe no fast Ca2+ wave following fertilization. Rather, we show distinct slow localized Ca2+ elevations associated with both fertilization and S-phase progression, and we show that both S-phase and zygotic polarization are dependent on pre-S-phase Ca2+ increases. Surprisingly, this Ca2+ requirement cannot be explained by co-dependence on a single G1/S-phase checkpoint, as S phase and zygotic polarization are differentially sensitive to pre-S-phase Ca2+ elevations and can be uncoupled. Furthermore, subsequent cell cycle progression through M phase is independent of localized actin polymerization and zygotic polarization. This absence of a morphogenesis checkpoint, together with the observed Ca2+-dependences of S phase and polarization, show that the regulation of zygotic division in the brown algae differs from that in other eukaryotic model systems, such as yeast and Drosophila.

Published
2008
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9. The green seaweed Ulva: a model system to study morphogenesis

Author

Frédéric Mineur, Olivier De Clerck, John H. F. Bothwell, Thomas Wichard, Juliet C. Coates, Bénédicte Charrier, Institute for Inorganic and Analytical Chemistry, Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Biological Sciences, Queen's University [Belfast] (QUB), School of Biological and Biomedical Sciences and Durham Energy Institute, Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Universiteit Gent = Ghent University [Belgium] (UGENT), School of Biosciences, University of Alabama at Birmingham [ Birmingham] (UAB)-School of Biosciences, Durham University, and Universiteit Gent = Ghent University (UGENT)

Subjects
0106 biological sciences, ENTEROMORPHA, ALGA ULVA, Plant Science, algal genetics, chlorophyta, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, lcsh:Plant culture, 01 natural sciences, Mini Review Article, AXENIC CULTURE, 03 medical and health sciences, Algae, LACTUCA CHLOROPHYTA, Botany, green tides, lcsh:SB1-1110, Ecosystem, GAMETE RELEASE, 14. Life underwater, GENETIC-CONTROL, model organism, 030304 developmental biology, holobiont, 0303 health sciences, biology, Primary producers, Ecology, 010604 marine biology & hydrobiology, Ulvophyceae, GENOME REVEALS, Biology and Life Sciences, multicellular organism, biology.organism_classification, EPIPHYTIC BACTERIAL COMMUNITY, Holobiont, Benthic zone, MUTABILIS, ARABIDOPSIS-THALIANA, Epiphyte, Sea lettuce
Abstract

International audience; Green macroalgae, mostly represented by the Ulvophyceae, the main multicellular branch of the Chlorophyceae, constitute important primary producers of marine and brackish coastal ecosystems. Ulva or sea lettuce species are some of the most abundant representatives, being ubiquitous in coastal benthic communities around the world. Nonetheless the genus also remains largely understudied. This review highlights Ulva as an exciting novel model organism for studies of algal growth, development and morphogenesis as well as mutualistic interactions. The key reasons that Ulva is potentially such a good model system are: (i) patterns of Ulva development can drive ecologically important events, such as the increasing number of green tides observed worldwide as a result of eutrophication of coastal waters, (ii) Ulva growth is symbiotic, with proper development requiring close association with bacterial epiphytes, (iii) Ulva is extremely developmentally plastic, which can shed light on the transition from simple to complex multicellularity and (iv) Ulva will provide additional information about the evolution of the green lineage.

Published
2015
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10. Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology

Author

Chris Harrod, Nessa E. O'Connor, Felipe Docmac, John H. F. Bothwell, and Carl J. Reddin

Subjects
Multidisciplinary, Ecology, Community, lcsh:R, Intertidal zone, lcsh:Medicine, δ15N, Biology, Benthic zone, Phytoplankton, Upwelling, Ecosystem, lcsh:Q, Chile, lcsh:Science, Research Article, Trophic level
Abstract

Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

Published
2015
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12. The evolution of Ca2+signalling in photosynthetic eukaryotes

Author

John H. F. Bothwell and Carl K.-Y. Ng

Subjects
Physiology, Fungi, Eukaryota, Ca2 signalling, Plant Science, Biological evolution, Biology, Photosynthesis, Biological Evolution, Homology (biology), Cell biology, Cytosol, Signalling, Botany, Calcium Signaling, Signal transduction, Phylogeny, Plant Physiological Phenomena
Abstract

Contents Summary 1 I. Introduction 1 II. Homology vs homoplasy 2 III. The structure and variation of [Ca2+]cyt signalling pathways 7 IV. A putative course of descent for plant [Ca2+]cyt signalling 9 V. Conclusion 13 Acknowledgements 14 References 14 Summary It is likely that cytosolic Ca2+ elevations have played a part in eukaryotic signal transduction for about the last 2 Gyr, being mediated by a group of molecules which are collectively known as the [Ca2+]cyt signalling toolkit. Different eukaryotes often display strikingly similar [Ca2+]cyt signalling elevations, which may reflect conservation of toolkit components (homology) or similar constraints acting on different toolkits (homoplasy). Certain toolkit components, which are presumably ancestral, are shared by plants and animals, but some components are unique to photosynthetic organisms. We propose that the structure of modern plant [Ca2+]cyt signalling toolkits may be explained by their modular adaptation from earlier pathways.

Published
2005
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13. Abnormalities in brain biochemistry associated with lack of dystrophin: studies of the mdx mouse

Author

Duncan H Blair, Stewart I. Head, Annie Maitland, Caroline Rae, William A. Bubb, John H. F. Bothwell, and Julian L Griffin

Subjects
Male, musculoskeletal diseases, Agonist, congenital, hereditary, and neonatal diseases and abnormalities, Cerebellum, mdx mouse, medicine.drug_class, Hippocampus, In Vitro Techniques, Muscular Dystrophies, Choline, Dystrophin, Mice, chemistry.chemical_compound, Oxygen Consumption, Reference Values, medicine, Animals, Muscular dystrophy, Genetics (clinical), Cerebral Cortex, biology, Muscimol, Brain, Receptors, GABA-A, medicine.disease, Mice, Inbred C57BL, Glucose, medicine.anatomical_structure, Neurology, Biochemistry, chemistry, Cerebral cortex, Pediatrics, Perinatology and Child Health, Mice, Inbred mdx, biology.protein, Female, Neurology (clinical)
Abstract

Biochemical abnormalities have been reported in dystrophin-deficient muscle of boys with Duchenne (severe Xp21) muscular dystrophy or in the murine (mdx) model of the disease. These abnormalities include altered energy metabolism and responses to osmotic shock. In contrast, the situation in brain is less well understood and it is probable that dystrophin is playing a different role (or roles) in this organ. In this study we conclude that the elevation in choline-containing compounds reported in mdx brain is confined to cerebellum and hippocampus in older (> 6 months) mice. We report alterations in glucose metabolism in mdx brain under normal, awake conditions, and a reduced response of brain metabolism to the gamma-aminobutyric acid(A) receptor agonist muscimol. Using brain cortical slices we found no difference in the response of dystrophic tissue to hypoosmotic shock, but increased, substrate-dependent oxygen consumption rates at low oxygen partial pressures.

Published
2002
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14. Swelling-activated Taurine and Creatine Effluxes from Rat Cortical Astrocytes are Pharmacologically Distinct

Author

Kishore K. Bhakoo, Peter Styles, and John H. F. Bothwell

Subjects
Anions, medicine.medical_specialty, Taurine, Time Factors, Physiology, Biophysics, Organic Anion Transporters, 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid, Biology, Creatine, chemistry.chemical_compound, Osmotic Pressure, Internal medicine, medicine, Animals, Inhibitory effect, Cells, Cultured, Cerebral Cortex, Niflumic acid, Biological Transport, Cell Biology, Rats, Endocrinology, Animals, Newborn, Biochemistry, chemistry, DIDS, Astrocytes, Nitrobenzoates, Shock (circulatory), Efflux, Swelling, medicine.symptom, medicine.drug
Abstract

Primary cultures of rat cortical astrocytes undergo a swelling-activated loss of taurine and creatine. In this study, the pharmacological characteristics of the taurine and creatine efflux pathways were compared, and significant differences were shown to exist between the two. Both taurine and creatine effluxes were rapidly activated upon exposure of astrocytes to hypo-osmotic media, and rapidly inactivated upon their return to iso-osmotic media. The relative rates of taurine and creatine efflux depended upon the magnitude of the hypo-osmotic shock. Anion-transport inhibitors strongly inhibited taurine efflux, with the order of potency being NPPB > DIDS > niflumic acid. DIDS and NPPB had less of an inhibitory effect on creatine efflux, whereas tamoxifen and niflumic acid actually stimulated creatine efflux. These data are consistent with separate pathways for taurine and creatine loss during astrocyte swelling.

Published
2002
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15. NOX or not? Evidence for algal NADPH oxidases

Author

Alexander Anderson, Julia M. Davies, John H. F. Bothwell, Alison G. Smith, and Anuphon Laohavisit

Subjects
Molecular Sequence Data, Botany, Eukaryota, Humans, NADPH Oxidases, Environmental ethics, Amino Acid Sequence, Plant Science, Biology, NOx
Abstract

We thank the UK EPSRC for funding and apologise to colleagues whose work could not be cited owing to space limitations.

Published
2011
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16. A Haploid System of Sex Determination in the Brown Alga Ectocarpus sp

Author

Akira F. Peters, John H. F. Bothwell, J. Mark Cock, Denis Roze, Marine Robuchon, Myriam Valero, Susana M. Coelho, Alexandre Cormier, Eugénie Pessia, Yves Van de Peer, Simon M. Dittami, Sophia Ahmed, Lieven Sterck, Remy Luthringer, Gabriel A. B. Marais, Erwan Corre, Jean-Marc Aury, Santé Végétale (SV), Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB), Végétaux marins et biomolécules, Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-GOEMAR-Centre National de la Recherche Scientifique (CNRS), Sexe et évolution, Département PEGASE [LBBE] (PEGASE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Evolutionary Biology and Ecology of Algae (EBEA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS), Center for Plant Systems Biology (PSB Center), Vlaams Instituut voor Biotechnologie [Ghent, Belgique] (VIB), Bezhin Rosko, Marine Biological Association Laboratory (MBA Laboratory), Marine Biological Association of the UK, Phophorylation de protéines et Pathologies Humaines (P3H), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Génomique métabolique (UMR 8030), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Department of Plant Biotechnology and Bioinformatics, Universiteit Gent = Ghent University (UGENT), Department of Plant Systems Biology, Flanders Institute for Biotechnology, Department of Genetics, Genomics Research Institute, University of Pretoria [South Africa], Belfast e-Science Centre [Belfast] (BESC), Queen's University [Belfast] (QUB), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Biologie Intégrative des Populations, École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), State University of Ghent, Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE), Sorbonne Universités, Ghent University [Belgium] (UGENT), Muséum national d'Histoire naturelle (MNHN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC), Universiteit Gent = Ghent University [Belgium] (UGENT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE)

Subjects
0106 biological sciences, Biology, Haploidy, Phaeophyta, 010603 evolutionary biology, 01 natural sciences, Genome, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, Negative selection, Gene, 030304 developmental biology, Genetics, 0303 health sciences, [SDV.GEN]Life Sciences [q-bio]/Genetics, Agricultural and Biological Sciences(all), Biochemistry, Genetics and Molecular Biology(all), [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Haplotype, Chromosome, Ectocarpus, Sex Determination Processes, biology.organism_classification, Sexual dimorphism, Ploidy, General Agricultural and Biological Sciences
Abstract

Summary Background A common feature of most genetic sex-determination systems studied so far is that sex is determined by nonrecombining genomic regions, which can be of various sizes depending on the species. These regions have evolved independently and repeatedly across diverse groups. A number of such sex-determining regions (SDRs) have been studied in animals, plants, and fungi, but very little is known about the evolution of sexes in other eukaryotic lineages. Results We report here the sequencing and genomic analysis of the SDR of Ectocarpus , a brown alga that has been evolving independently from plants, animals, and fungi for over one giga-annum. In Ectocarpus , sex is expressed during the haploid phase of the life cycle, and both the female (U) and the male (V) sex chromosomes contain nonrecombining regions. The U and V of this species have been diverging for more than 70 mega-annum, yet gene degeneration has been modest, and the SDR is relatively small, with no evidence for evolutionary strata. These features may be explained by the occurrence of strong purifying selection during the haploid phase of the life cycle and the low level of sexual dimorphism. V is dominant over U, suggesting that femaleness may be the default state, adopted when the male haplotype is absent. Conclusions The Ectocarpus UV system has clearly had a distinct evolutionary trajectory not only to the well-studied XY and ZW systems but also to the UV systems described so far. Nonetheless, some striking similarities exist, indicating remarkable universality of the underlying processes shaping sex chromosome evolution across distant lineages.

Published
2014
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17. Hypo-osmotic swelling-activated release of organic osmolytes in brain slices: implications for brain oedema in vivo

Author

Ruth Dixon, Peter Styles, Caroline Rae, Kishore K. Bhakoo, and John H. F. Bothwell

Subjects
Niflumic acid, Glutamate receptor, Hypotaurine, Metabolism, Biology, Biochemistry, Phosphocreatine, Cellular and Molecular Neuroscience, chemistry.chemical_compound, chemistry, Osmolyte, medicine, Osmoregulation, Intracellular, medicine.drug
Abstract

A decrease in the intracellular levels of osmotically active species has invariably been seen after swelling of mammalian brain tissue preparations. The exact identity of the species, and the manner of their decrease, remain to be described. We investigated the swelling-activated decrease of organic osmolytes in rat cortical brain slices using (1)H- and (31)P-magnetic resonance spectroscopy. We found that acute hypo-osmotic shock causes decreases in the levels of a range of intracellular amino acids and amino acid derivatives, N-acetyl-aspartate, creatine, GABA, glutamate, hypotaurine, and also in the levels of the methylamines glycerol-phosphorylcholine, phosphorylcholine and choline. Incubation of cortical slices with the anion channel blockers niflumic acid and tamoxifen caused inhibition of organic osmolyte efflux, suggesting that such osmolyte efflux occurs through anion channels. Intracellular phosphocreatine was also seen to decrease during acute hypo-osmotic superfusion, although intracellular ATP remained constant. In addition, the acidification of an intracellular compartment was observed during hypo-osmotic superfusion. Our results suggest a link between brain energy reserve and brain osmoregulation.

Published
2001
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18. Calcium uptake by plant cells – channels and pumps acting in concert

Author

Colin Brownlee, John H. F. Bothwell, Julia M. Davies, and Henk Miedema

Subjects
Membrane potential, Patch-Clamp Techniques, Potassium Channels, biology, Arabidopsis Proteins, Calcium pump, Calcium channel, ATPase, Arabidopsis, Ion Pumps, Plant Science, Plant cell, Cell biology, Calcium ATPase, Proton-Translocating ATPases, Potassium Channels, Tandem Pore Domain, Membrane, biology.protein, Plasma membrane Ca2+ ATPase, Calcium, Calcium Channels, Plant Proteins
Abstract

How do plant cells accomplish a net uptake of Ca 2+ but keep the membrane potential under control? Consideration of the voltage dependence of the depolarization-activated calcium channel and hyperpolarization-activated calcium channel types, and two other major transporters in the plasma membrane, the H + -ATPase and I K,out , suggests that one channel is well suited for both nutritive and signalling Ca 2+ uptake whereas the other could be limited to a signalling function.

Published
2001
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19. Chloride channel antagonists perturb growth and morphology of Neurospora crassa

Author

Gary R. Devine, Julia M. Davies, Frederick D. Northrop, Guy T Hanke, and John H. F. Bothwell

Subjects
Antifungal Agents, Carboxylic acid, Microbiology, Neurospora crassa, Chloride Channels, Genetics, medicine, Biomass, Molecular Biology, Anthracenes, chemistry.chemical_classification, biology, Chemistry, fungi, Niflumic acid, Crassa, Niflumic Acid, Hydrogen-Ion Concentration, biology.organism_classification, Culture Media, Agar, Ethacrynic Acid, Enzyme, Biochemistry, Cytoplasm, Chloride channel, Cell Division, medicine.drug, Etacrynic acid
Abstract

The chloride channel antagonists anthracene-9-carboxylic acid, ethacrynic acid and niflumic acid were found to be fungistatic and morphogenic when tested against the ascomycete Neurospora crassa. Potency increased with decreasing pH, suggesting that the protonated forms of the compounds were active. Niflumic acid produced the most pronounced growth aberrations which may reflect an ability to acidify the cytoplasm and block the plasma membrane anion channel of N. crassa.

Published
2001
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20. Cell cycles and endocycles in the model brown seaweed,Ectocarpus siliculosus

Author

J. M. Cock, Akira F. Peters, John H. F. Bothwell, Susana M. Coelho, and D. Marie

Subjects
Chromosome number, Ectocarpus siliculosus, Cell Cycle, Plant Science, Ectocarpus, Biology, Cell cycle, Phaeophyta, biology.organism_classification, Genome, Article Addendum, Aquatic organisms, Polyploidy, Microscopy, Fluorescence, Brown seaweed, Botany
Abstract

The recent announcement of the first genome sequence of a brown macroalga, the filamentous Ectocarpus,1 has been accompanied by a number of companion papers in New Phytologist. In a paper which contributes to this special issue, we classified the core cell cycle components of Ectocarpus, comparing them to the previously studied cell cycle components of diatoms. We then carried out fluorescence microscopy experiments to show that the Ectocarpus cell cycle could be deregulated during early development to give endopolyploid adults. We discuss here how our findings complement recent studies on endopolyploidy in plant and algal systems.

Published
2010
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21. Genome structure and metabolic features in the red seaweed Chondrus crispus shed light on evolution of the Archaeplastida

Author

Tristan Barbeyron, Wilfrid Carré, Michael Katinka, Loraine Brillet, Klaus Valentin, Karine Labadie, Betina M. Porcel, Zofia Nehr, Francisco Cabello-Hurtado, Mirjam Czjzek, Benjamin Noel, Philippe Deschamps, Susana M. Coelho, John H. F. Bothwell, Pascal J. Lopez, Marek Eliáš, François Artiguenave, François-Yves Bouget, Thierry Tonon, Jean Weissenbach, Christophe Colleoni, Deirdre H. McLachlan, Ahmed A. Moustafa, Cécile Hervé, Olivier Panaud, Catherine Boyen, Jonas Collén, Antonios Zambounis, Frédéric Partensky, Cristian Chaparro, Ludovic Delage, Jose Fernandes Barbosa-Neto, Salvador Capella-Gutierrez, Bernard Kloareg, Nathalie Kowalczyk, Gaelle Samson, Gurvan Michel, Simon M. Dittami, Jean-Marc Aury, J. Mark Cock, Patrick Wincker, Agnès Groisillier, Pi Nyvall Collén, Bénédicte Charrier, Corinne Da Silva, Catherine Leblanc, Lionel Cladière, Alok Arun, Laurence Meslet-Cladiere, Claire M. M. Gachon, Sylvie Rousvoal, Kamel Jabbari, Stefan A. Rensing, Toni Gabaldón, Steven G. Ball, Aikaterini Symeonidi, Julie Poulain, Végétaux marins et biomolécules, Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-GOEMAR-Centre National de la Recherche Scientifique (CNRS), Procaryotes Phototrophes Marins = MArine Phototrophic Prokaryotes (MAPP), Adaptation et diversité en milieu marin (AD2M), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Génomique métabolique (UMR 8030), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire Génome et développement des plantes (LGDP), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Department of Plant Physiology, Faculty of Sciences, Charles University [Prague] (CU), Belfast e-Science Centre [Belfast] (BESC), Queen's University [Belfast] (QUB), Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire océanologique de Banyuls (OOB), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Universitat Pompeu Fabra [Barcelona] (UPF), Center for Genomic Regulation (CRG-UPF), CIBER de Epidemiología y Salud Pública (CIBERESP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Scottish Association for Marine Science (SAMS), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Biology and Biotechnology Graduate Program, American University in Cairo, American University in Cairo, University of Freiburg [Freiburg], Freiburg Initiative in Systems Biology, Centre for Research and Technology Hellas (CERTH), Institut de Génomique d'Evry (IG), Université Paris-Saclay-Institut de Biologie François JACOB (JACOB), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), MArine Phototrophic Prokaryotes (MAPP), Adaptation et diversité en milieu marin (ADMM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE), Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Charles University [Prague], Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Universitat Pompeu Fabra [Barcelona], Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Station biologique de Roscoff [Roscoff] (SBR), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Center for Research and Technology Hellas, Institut de Biologie François JACOB (JACOB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut National de la Recherche Agronomique (INRA)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire océanologique de Banyuls (OOB), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), and Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Transposable element, Genome evolution, [SDV]Life Sciences [q-bio], Molecular Sequence Data, Bacterial genome size, Biology, Chondrus, MESH: Base Sequence, MESH: RNA, Plant, Genes, Plant, 01 natural sciences, Genome, Evolution, Molecular, 03 medical and health sciences, MESH: Genes, Plant, 14. Life underwater, Gene, Genome size, MESH: Evolution, Molecular, 030304 developmental biology, Plant Proteins, Genetics, 0303 health sciences, Multidisciplinary, MESH: Molecular Sequence Data, Base Sequence, MESH: Plant Proteins, Archaeplastida, Biological Sciences, biology.organism_classification, MicroRNAs, RNA, Plant, MESH: MicroRNAs, MESH: Chondrus, 010606 plant biology & botany
Abstract

Red seaweeds are key components of coastal ecosystems and are economically important as food and as a source of gelling agents, but their genes and genomes have received little attention. Here we report the sequencing of the 105-Mbp genome of the florideophyte Chondrus crispus (Irish moss) and the annotation of the 9,606 genes. The genome features an unusual structure characterized by gene-dense regions surrounded by repeat-rich regions dominated by transposable elements. Despite its fairly large size, this genome shows features typical of compact genomes, e.g., on average only 0.3 introns per gene, short introns, low median distance between genes, small gene families, and no indication of large-scale genome duplication. The genome also gives insights into the metabolism of marine red algae and adaptations to the marine environment, including genes related to halogen metabolism, oxylipins, and multicellularity (microRNA processing and transcription factors). Particularly interesting are features related to carbohydrate metabolism, which include a minimalistic gene set for starch biosynthesis, the presence of cellulose synthases acquired before the primary endosymbiosis showing the polyphyly of cellulose synthesis in Archaeplastida, and cellulases absent in terrestrial plants as well as the occurrence of a mannosylglycerate synthase potentially originating from a marine bacterium. To explain the observations on genome structure and gene content, we propose an evolutionary scenario involving an ancestral red alga that was driven by early ecological forces to lose genes, introns, and intergenetic DNA; this loss was followed by an expansion of genome size as a consequence of activity of transposable elements.

Published
2013
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22. The Ectocarpus genome and the independent evolution of multicellularity in brown algae

Author

Jean-Marc Aury, Frithjof C. Küpper, Diego Miranda-Saavedra, John H. F. Bothwell, Claire Jubin, Chris Bowler, Bernhard Gschloessl, James W. Tregear, Andrés Ritter, Andrew E. Allen, Carolyn A. Napoli, Ludovic Delage, Bernard Kloareg, Takahiro Yamagishi, Pi Nyvall-Collén, Svenja Heesch, Julia Morales, Gaelle Samson, Kei Kimura, Ga Youn Cho, Grigoris D. Amoutzias, Yves Van de Peer, Simon M. Dittami, Kenny Billiau, Julie Poulain, François Artiguenave, Sylvie Doulbeau, Marek Eliáš, Bank Beszteri, Carl J. Carrano, Daniel Lang, Florian Maumus, Stefan A. Rensing, Jonathan H. Badger, Béatrice Segurens, Martina Strittmatter, Sylvie Rousvoal, Hervé Moreau, Patrice Lerouge, Colin Brownlee, Betsy Read, Akira F. Peters, J. Mark Cock, Corinne Da Silva, Declan C. Schroeder, Catherine Boyen, Pierre Rouzé, Eric Bonnet, Jonas Collén, Susana M. Coelho, Aude Le Bail, Kamel Jabbari, David R. Nelson, Thierry Tonon, Pascal J. Lopez, Véronique Anthouard, Hadi Quesneville, Manoj P. Samanta, Delphine Scornet, Klaus Valentin, Nicolas Delaroque, Bénédicte Charrier, Cindy Martens, Peter von Dassow, Martin Lohr, Garry Farnham, Chikako Nagasato, Claire M. M. Gachon, Gurvan Michel, Lieven Sterck, Philippe Potin, Erwan Corre, Catherine Leblanc, Taizo Motomura, Cyril Pommier, Patrick Wincker, Hiroshi Kawai, Publica, Végétaux marins et biomolécules, Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-GOEMAR-Centre National de la Recherche Scientifique (CNRS), Department of Plant Systems Biology, State University of Ghent, J Craig Venter Institute, Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Marine Biological Association, Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), San Diego State University (SDSU), Phophorylation de protéines et Pathologies Humaines (P3H), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Diversité et adaptation des plantes cultivées (UMR DIAPC), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Charles University [Prague], Scottish Association for Marine Science (SAMS), Kobe University, Institute of Algological Research [Muroran], Hokkaido University, Fakultät für Biologie = Faculty of Biology [Freiburg], Albert-Ludwigs-Universität Freiburg, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Johannes Gutenberg - Universität Mainz (JGU), École normale supérieure - Paris (ENS Paris), Institut de biologie de l'Ecole Normale Supérieure (IBENS), École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Haematology, University of Cambridge [UK] (CAM), Mer et santé (MS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Arizona, The University of Tennessee Health Science Center [Memphis] (UTHSC), Unité de Recherche Génomique Info (URGI), Institut National de la Recherche Agronomique (INRA), California State University [Los Angeles] (CAL STATE LA), Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Systemix Institute, Savelli, Bruno, Center for Plant Systems Biology (PSB Center), Vlaams Instituut voor Biotechnologie [Ghent, Belgique] (VIB), J. Craig Venter Institute, Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de biologie de l'ENS Paris (IBENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (AD2M), Fraunhofer Institute for Cell Therapy and Immunology (Fraunhofer IZI), Fraunhofer (Fraunhofer-Gesellschaft), Charles University [Prague] (CU), Hokkaido University [Sapporo, Japan], Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Université Paris sciences et lettres (PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris

Subjects
0106 biological sciences, Lineage (evolution), Molecular Sequence Data, Phaeophyta, 01 natural sciences, Genome, Evolution, Molecular, 03 medical and health sciences, Algae, [SDV.BDD] Life Sciences [q-bio]/Development Biology, Botany, BIOLOGIE CELLULAIRE, Animals, 14. Life underwater, [SDV.BDD]Life Sciences [q-bio]/Development Biology, flore marine, Phylogeny, Organism, ComputingMilieux_MISCELLANEOUS, phéophycées, 030304 developmental biology, 0303 health sciences, Multidisciplinary, biology, Ectocarpus siliculosus, Algal Proteins, Eukaryota, Pigments, Biological, Ectocarpus, 15. Life on land, biology.organism_classification, Biological Evolution, Brown algae, Multicellular organism, Evolutionary biology, algues brunes, Biologie, Signal Transduction, 010606 plant biology & botany
Abstract

Brown algae (Phaeophyceae) are complex photosynthetic organisms with a very different evolutionary history to green plants, to which they are only distantly related. These seaweeds are the dominant species in rocky coastal ecosystems and they exhibit many interesting adaptations to these, often harsh, environments. Brown algae are also one of only a small number of eukaryotic lineages that have evolved complex multicellularity (Fig. 1). We report the 214 million base pair (Mbp) genome sequence of the filamentous seaweed Ectocarpus siliculosus (Dillwyn) Lyngbye, a model organism for brown algae, closely related to the kelps (Fig. 1). Genome features such as the presence of an extended set of light-harvesting and pigment biosynthesis genes and new metabolic processes such as halide metabolism help explain the ability of this organism to cope with the highly variable tidal environment. The evolution of multicellularity in this lineage is correlated with the presence of a rich array of signal transduction genes. Of particular interest is the presence of a family of receptor kinases, as the independent evolution of related molecules has been linked with the emergence of multicellularity in both the animal and green plant lineages. The Ectocarpus genome sequence represents an important step towards developing this organism as a model species, providing the possibility to combine genomic and genetic approaches to explore these and other aspects of brown algal biology further. © 2010 Macmillan Publishers Limited. All rights reserved.

Published
2010
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23. Feedback control of reactive oxygen and Ca2+ signaling during brown algal embryogenesis

Author

Colin Brownlee, Susana M. Coelho, and John H. F. Bothwell

Subjects
chemistry.chemical_classification, Fluorescence-lifetime imaging microscopy, Reactive oxygen species, Phospholipase C, Confocal, Embryogenesis, fungi, chemistry.chemical_element, food and beverages, Plant Science, Biology, Calcium, biochemical phenomena, metabolism, and nutrition, Oxygen, Cell biology, Article Addendum, Biochemistry, chemistry, Intracellular
Abstract

In a recent paper in Planta, we combined novel confocal reflectance imaging of intracellular reactive oxygen species (ROS) with inhibition-of-growth experiments to show that ROS help to direct polarized growth in brown algal zygotes. Using confocal fluorescence imaging of intracellular Ca(2+) distributions, we were also able to show an interaction between ROS and Ca(2+) signaling. The modulation of intracellular Ca(2+) signals by reactive oxygen species (ROS) is a common motif in many plant and algal systems, but our Planta paper is its first demonstration during early development. We explain here how our findings complement a number of recent studies on polarized growth in plant and algal systems.

Published
2008

24. A tip-high, Ca(2+) -interdependent, reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes

Author

Susana M. Coelho, Colin Brownlee, and John H. F. Bothwell

Subjects
chemistry.chemical_classification, Reactive oxygen species, Microscopy, Confocal, biology, Phospholipase C, Fucus serratus, Reproduction, chemistry.chemical_element, Endogeny, Plant Science, Calcium, biology.organism_classification, Rhizoid, chemistry, Type C Phospholipases, Botany, Fucus, cardiovascular system, Genetics, Biophysics, Reactive Oxygen Species, Intracellular
Abstract

We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2',7'-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca(2+)](cyt) gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca(2+)](cyt) gradient. Such modulation of intracellular [Ca(2+)](cyt) signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.

Published
2007

25. Biolistic delivery of Ca2+ dyes into plant and algal cells

Author

John H. F. Bothwell, Carl K.-Y. Ng, Martin R. McAinsh, Alistair M. Hetherington, Glen L. Wheeler, and Colin Brownlee

Subjects
Cell type, Chlamydomonas reinhardtii, Chlorophyceae, Commelina, Plant Science, Chlorophyta, Cytosol, Guard cell, Botany, Genetics, Animals, Fluorescent Dyes, biology, fungi, Chlamydomonas, food and beverages, Eukaryota, Biological Transport, Cell Biology, Biolistics, biology.organism_classification, Plant cell, Biophysics, Commelina communis, Calcium
Abstract

In eukaryotes, changes in cytosolic Ca2+ concentrations ([Ca2+]cyt) are associated with a number of environmental and developmental stimuli. However, measuring [Ca2+]cyt changes in single plant or algal cells is often problematic. Although a wide range of Ca2+-sensitive fluorescent dyes is available, they are often difficult to introduce into plant cells. Micro-injection is the most robust method for dye loading, but is time-consuming, technically demanding, and unsuitable in many cell types. To overcome these problems, we have adapted biolistic techniques to load Ca2+-sensitive dyes into guard cells of the flowering plant, Commelina communis, cells of the green alga Chlamydomonas reinhardtii, and zygotes of the brown alga, Fucus serratus. Using this approach, we have been able to monitor [Ca2+]cyt changes in response to various stimuli, including a novel [Ca2+]cyt response in C. reinhardtii. The method allows the use of free acid and dextran-conjugated dyes. Biolistic loading of differentiated plant cells is easier, quicker, and more widely applicable than micro-injection, and should broaden the study of plant signal transduction.

Published
2006

26. Reactive oxygen species produced by NADPH oxidase regulate plant cell growth

Author

Panagiota Mylona, Silvia Costa, Julia M. Davies, Julia Foreman, Jonathan D. G. Jones, Henk Miedema, Paul Linstead, Colin Brownlee, Liam Dolan, Vadim Demidchik, John H. F. Bothwell, and Miguel Angel Torres

Subjects
Arabidopsis, Biology, Root hair, Root hair elongation, Root hair initiation, Genes, Plant, Plant Roots, Extracellular, Arabidopsis thaliana, Calcium Signaling, Alleles, In Situ Hybridization, chemistry.chemical_classification, Reactive oxygen species, Multidisciplinary, NADPH oxidase, Arabidopsis Proteins, NADPH Oxidases, biology.organism_classification, Plant cell, Cell biology, Electrophysiology, Biochemistry, chemistry, Mutation, biology.protein, Calcium, Calcium Channels, Reactive Oxygen Species, Cell Division
Abstract

Cell expansion is a central process in plant morphogenesis, and the elongation of roots and root hairs is essential for uptake of minerals and water from the soil. Ca2+ influx from the extracellular store is required for (and sets the rates of) cell elongation in roots. Arabidopsis thaliana rhd2 mutants are defective in Ca2+ uptake and consequently cell expansion is compromised--rhd2 mutants have short root hairs and stunted roots. To determine the regulation of Ca2+ acquisition in growing root cells we show here that RHD2 is an NADPH oxidase, a protein that transfers electrons from NADPH to an electron acceptor leading to the formation of reactive oxygen species (ROS). We show that ROS accumulate in growing wild-type (WT) root hairs but their levels are markedly decreased in rhd2 mutants. Blocking the activity of the NADPH oxidase with diphenylene iodonium (DPI) inhibits ROS formation and phenocopies Rhd2-. Treatment of rhd2 roots with ROS partly suppresses the mutant phenotype and stimulates the activity of plasma membrane hyperpolarization-activated Ca2+ channels, the predominant root Ca2+ acquisition system. This indicates that NADPH oxidases control development by making ROS that regulate plant cell expansion through the activation of Ca2+ channels.

Published
2002

30. Britain's postdocs unite

Author

John H. F. Bothwell

Subjects
Physics, Career Mobility, Multidisciplinary, Research, Age Factors, Workforce, Societies, Research Personnel, United Kingdom
Published
2006
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