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1.
Cell ; 174(2): 448-464.e24, 2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-30007417

RESUMO

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via land-plant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.


Assuntos
Chara/genética , Genoma de Planta , Evolução Biológica , Parede Celular/metabolismo , Chara/crescimento & desenvolvimento , Embriófitas/genética , Redes Reguladoras de Genes , Pentosiltransferases/genética , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma
2.
Nature ; 633(8031): 872-877, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39198644

RESUMO

Early plant responses to different stress situations often encompass cytosolic Ca2+ increases, plasma membrane depolarization and the generation of reactive oxygen species1-3. However, the mechanisms by which these signalling elements are translated into defined physiological outcomes are poorly understood. Here, to study the basis for encoding of specificity in plant signal processing, we used light-gated ion channels (channelrhodopsins). We developed a genetically engineered channelrhodopsin variant called XXM 2.0 with high Ca2+ conductance that enabled triggering cytosolic Ca2+ elevations in planta. Plant responses to light-induced Ca2+ influx through XXM 2.0 were studied side by side with effects caused by an anion efflux through the light-gated anion channelrhodopsin ACR1 2.04. Although both tools triggered membrane depolarizations, their activation led to distinct plant stress responses: XXM 2.0-induced Ca2+ signals stimulated production of reactive oxygen species and defence mechanisms; ACR1 2.0-mediated anion efflux triggered drought stress responses. Our findings imply that discrete Ca2+ signals and anion efflux serve as triggers for specific metabolic and transcriptional reprogramming enabling plants to adapt to particular stress situations. Our optogenetics approach unveiled that within plant leaves, distinct physiological responses are triggered by specific ion fluxes, which are accompanied by similar electrical signals.


Assuntos
Arabidopsis , Sinalização do Cálcio , Cálcio , Channelrhodopsins , Luz , Optogenética , Ânions/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Cálcio/metabolismo , Sinalização do Cálcio/efeitos da radiação , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Channelrhodopsins/metabolismo , Channelrhodopsins/genética , Citosol/metabolismo , Secas , Condutividade Elétrica , Transporte de Íons/efeitos da radiação , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação
3.
Nature ; 595(7868): 572-577, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34044428

RESUMO

BNT162b2, a nucleoside-modified mRNA formulated in lipid nanoparticles that encodes the SARS-CoV-2 spike glycoprotein (S) stabilized in its prefusion conformation, has demonstrated 95% efficacy in preventing COVID-191. Here we extend a previous phase-I/II trial report2 by presenting data on the immune response induced by BNT162b2 prime-boost vaccination from an additional phase-I/II trial in healthy adults (18-55 years old). BNT162b2 elicited strong antibody responses: at one week after the boost, SARS-CoV-2 serum geometric mean 50% neutralizing titres were up to 3.3-fold above those observed in samples from individuals who had recovered from COVID-19. Sera elicited by BNT162b2 neutralized 22 pseudoviruses bearing the S of different SARS-CoV-2 variants. Most participants had a strong response of IFNγ+ or IL-2+ CD8+ and CD4+ T helper type 1 cells, which was detectable throughout the full observation period of nine weeks following the boost. Using peptide-MHC multimer technology, we identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week after the boost, epitope-specific CD8+ T cells of the early-differentiated effector-memory phenotype comprised 0.02-2.92% of total circulating CD8+ T cells and were detectable (0.01-0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes that are conserved in a broad range of variants, at well-tolerated doses.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Linfócitos T/imunologia , Adolescente , Adulto , Vacina BNT162 , Linfócitos T CD8-Positivos/imunologia , COVID-19/virologia , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/efeitos adversos , Epitopos de Linfócito T/imunologia , Feminino , Humanos , Imunoglobulina G/imunologia , Memória Imunológica , Interferon gama/imunologia , Interleucina-2/imunologia , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Células Th1/imunologia , Adulto Jovem
4.
Proc Natl Acad Sci U S A ; 121(7): e2313343121, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38315839

RESUMO

Plants tightly control growth of their lateral organs, which led to the concept of apical dominance. However, outgrowth of the dormant lateral primordia is sensitive to the plant's nutritional status, resulting in an immense plasticity in plant architecture. While the impact of hormonal regulation on apical dominance is well characterized, the prime importance of sugar signaling to unleash lateral organ formation has just recently emerged. Here, we aimed to identify transcriptional regulators, which control the trade-off between growth of apical versus lateral organs. Making use of locally inducible gain-of-function as well as single and higher-order loss-of-function approaches of the sugar-responsive S1-basic-leucine-zipper (S1-bZIP) transcription factors, we disclosed their largely redundant function in establishing apical growth dominance. Consistently, comprehensive phenotypical and analytical studies of S1-bZIP mutants show a clear shift of sugar and organic nitrogen (N) allocation from apical to lateral organs, coinciding with strong lateral organ outgrowth. Tissue-specific transcriptomics reveal specific clade III SWEET sugar transporters, crucial for long-distance sugar transport to apical sinks and the glutaminase GLUTAMINE AMIDO-TRANSFERASE 1_2.1, involved in N homeostasis, as direct S1-bZIP targets, linking the architectural and metabolic mutant phenotypes to downstream gene regulation. Based on these results, we propose that S1-bZIPs control carbohydrate (C) partitioning from source leaves to apical organs and tune systemic N supply to restrict lateral organ formation by C/N depletion. Knowledge of the underlying mechanisms controlling plant C/N partitioning is of pivotal importance for breeding strategies to generate plants with desired architectural and nutritional characteristics.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica , Melhoramento Vegetal , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Plantas/metabolismo , Transdução de Sinais/genética , Açúcares , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
5.
Nature ; 586(7830): 594-599, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32998157

RESUMO

An effective vaccine is needed to halt the spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic. Recently, we reported safety, tolerability and antibody response data from an ongoing placebo-controlled, observer-blinded phase I/II coronavirus disease 2019 (COVID-19) vaccine trial with BNT162b1, a lipid nanoparticle-formulated nucleoside-modified mRNA that encodes the receptor binding domain (RBD) of the SARS-CoV-2 spike protein1. Here we present antibody and T cell responses after vaccination with BNT162b1 from a second, non-randomized open-label phase I/II trial in healthy adults, 18-55 years of age. Two doses of 1-50 µg of BNT162b1 elicited robust CD4+ and CD8+ T cell responses and strong antibody responses, with RBD-binding IgG concentrations clearly above those seen in serum from a cohort of individuals who had recovered from COVID-19. Geometric mean titres of SARS-CoV-2 serum-neutralizing antibodies on day 43 were 0.7-fold (1-µg dose) to 3.5-fold (50-µg dose) those of the recovered individuals. Immune sera broadly neutralized pseudoviruses with diverse SARS-CoV-2 spike variants. Most participants had T helper type 1 (TH1)-skewed T cell immune responses with RBD-specific CD8+ and CD4+ T cell expansion. Interferon-γ was produced by a large fraction of RBD-specific CD8+ and CD4+ T cells. The robust RBD-specific antibody, T cell and favourable cytokine responses induced by the BNT162b1 mRNA vaccine suggest that it has the potential to protect against COVID-19 through multiple beneficial mechanisms.


Assuntos
Anticorpos Antivirais/imunologia , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Células Th1/imunologia , Vacinas Virais/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , COVID-19 , Vacinas contra COVID-19 , Infecções por Coronavirus/prevenção & controle , Citocinas/imunologia , Feminino , Alemanha , Humanos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Células Th1/citologia , Vacinas Virais/administração & dosagem , Vacinas Virais/efeitos adversos , Adulto Jovem
6.
Plant J ; 118(6): 2219-2232, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38602250

RESUMO

Sugar beet (Beta vulgaris) is the major sugar-producing crop in Europe and Northern America, as the taproot stores sucrose at a concentration of around 20%. Genome sequence analysis together with biochemical and electrophysiological approaches led to the identification and characterization of the TST sucrose transporter driving vacuolar sugar accumulation in the taproot. However, the sugar transporters mediating sucrose uptake across the plasma membrane of taproot parenchyma cells remained unknown. As with glucose, sucrose stimulation of taproot parenchyma cells caused inward proton fluxes and plasma membrane depolarization, indicating a sugar/proton symport mechanism. To decipher the nature of the corresponding proton-driven sugar transporters, we performed taproot transcriptomic profiling and identified the cold-induced PMT5a and STP13 transporters. When expressed in Xenopus laevis oocytes, BvPMT5a was characterized as a voltage- and H+-driven low-affinity glucose transporter, which does not transport sucrose. In contrast, BvSTP13 operated as a high-affinity H+/sugar symporter, transporting glucose better than sucrose, and being more cold-tolerant than BvPMT5a. Modeling of the BvSTP13 structure with bound mono- and disaccharides suggests plasticity of the binding cleft to accommodate the different saccharides. The identification of BvPMT5a and BvSTP13 as taproot sugar transporters could improve breeding of sugar beet to provide a sustainable energy crop.


Assuntos
Beta vulgaris , Glucose , Proteínas de Plantas , Raízes de Plantas , Sacarose , Animais , Beta vulgaris/citologia , Beta vulgaris/genética , Beta vulgaris/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Glucose/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Membrana Transportadoras/genética , Oócitos/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/genética , Prótons , Sacarose/metabolismo , Xenopus laevis
7.
New Phytol ; 2024 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-39370767

RESUMO

The evolution of adjustable stomatal pores, enabling CO2 acquisition, was one of the most significant events in the development of life on land. Here, we investigate how the guard cell signalling pathways that regulate stomatal movements evolved. We compare fern and angiosperm guard cell transcriptomes and physiological responses, and examine the functionality of ion channels from diverse plant species. We find that, despite conserved expression in guard cells, fern anion channels from the SLAC/SLAH family are not activated by the same abscisic acid (ABA) pathways that provoke stomatal closure in angiosperms. Accordingly, we find an insensitivity of fern stomata to ABA. Moreover, our analysis points to a complex evolutionary history, featuring multiple gains and/or losses of SLAC activation mechanisms, as these channels were recruited to a role in stomatal closure. Our results show that the guard cells of flowering and nonflowering plants share similar core features, with lineage-specific and ecological niche-related adaptations, likely underlying differences in behaviour.

8.
Med Microbiol Immunol ; 213(1): 6, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38722338

RESUMO

To date, there is no licensed vaccine for Middle East respiratory syndrome coronavirus (MERS-CoV). Therefore, MERS-CoV is one of the diseases targeted by the Coalition for Epidemic Preparedness Innovations (CEPI) vaccine development programs and has been classified as a priority disease by the World Health Organization (WHO). An important measure of vaccine immunogenicity and antibody functionality is the detection of virus-neutralizing antibodies. We have developed and optimized a microneutralization assay (MNA) using authentic MERS-CoV and standardized automatic counting of virus foci. Compared to our standard virus neutralization assay, the MNA showed improved sensitivity when analyzing 30 human sera with good correlation of results (Spearman's correlation coefficient r = 0.8917, p value < 0.0001). It is important to use standardized materials, such as the WHO international standard (IS) for anti-MERS-CoV immunoglobulin G, to compare the results from clinical trials worldwide. Therefore, in addition to the neutralizing titers (NT50 = 1384, NT80 = 384), we determined the IC50 and IC80 of WHO IS in our MNA to be 0.67 IU/ml and 2.6 IU/ml, respectively. Overall, the established MNA is well suited to reliably quantify vaccine-induced neutralizing antibodies with high sensitivity.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Coronavírus da Síndrome Respiratória do Oriente Médio , Testes de Neutralização , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Humanos , Testes de Neutralização/métodos , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/diagnóstico , Animais , Concentração Inibidora 50 , Sensibilidade e Especificidade
9.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34504003

RESUMO

Plants adjust their energy metabolism to continuous environmental fluctuations, resulting in a tremendous plasticity in their architecture. The regulatory circuits involved, however, remain largely unresolved. In Arabidopsis, moderate perturbations in photosynthetic activity, administered by short-term low light exposure or unexpected darkness, lead to increased lateral root (LR) initiation. Consistent with expression of low-energy markers, these treatments alter energy homeostasis and reduce sugar availability in roots. Here, we demonstrate that the LR response requires the metabolic stress sensor kinase Snf1-RELATED-KINASE1 (SnRK1), which phosphorylates the transcription factor BASIC LEUCINE ZIPPER63 (bZIP63) that directly binds and activates the promoter of AUXIN RESPONSE FACTOR19 (ARF19), a key regulator of LR initiation. Consistently, starvation-induced ARF19 transcription is impaired in bzip63 mutants. This study highlights a positive developmental function of SnRK1. During energy limitation, LRs are initiated and primed for outgrowth upon recovery. Hence, this study provides mechanistic insights into how energy shapes the agronomically important root system.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Metabolismo Energético , Homeostase , Raízes de Plantas/crescimento & desenvolvimento , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação da Expressão Gênica de Plantas , Fosforilação , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição/genética
10.
PLoS Biol ; 18(12): e3000964, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33296375

RESUMO

The carnivorous plant Dionaea muscipula harbors multicellular trigger hairs designed to sense mechanical stimuli upon contact with animal prey. At the base of the trigger hair, mechanosensation is transduced into an all-or-nothing action potential (AP) that spreads all over the trap, ultimately leading to trap closure and prey capture. To reveal the molecular basis for the unique functional repertoire of this mechanoresponsive plant structure, we determined the transcriptome of D. muscipula's trigger hair. Among the genes that were found to be highly specific to the trigger hair, the Shaker-type channel KDM1 was electrophysiologically characterized as a hyperpolarization- and acid-activated K+-selective channel, thus allowing the reuptake of K+ ions into the trigger hair's sensory cells during the hyperpolarization phase of the AP. During trap development, the increased electrical excitability of the trigger hair is associated with the transcriptional induction of KDM1. Conversely, when KDM1 is blocked by Cs+ in adult traps, the initiation of APs in response to trigger hair deflection is reduced, and trap closure is suppressed. KDM1 thus plays a dominant role in K+ homeostasis in the context of AP and turgor formation underlying the mechanosensation of trigger hair cells and thus D. muscipula's hapto-electric signaling.


Assuntos
Droseraceae/genética , Droseraceae/metabolismo , Canais de Potássio/metabolismo , Potenciais de Ação/fisiologia , Transporte Biológico , Fenômenos Eletrofisiológicos , Expressão Gênica/genética , Regulação da Expressão Gênica de Plantas/genética , Íons , Mecanorreceptores/metabolismo , Mecanorreceptores/fisiologia , Folhas de Planta/fisiologia , Potássio/metabolismo , Canais de Potássio/fisiologia , Transdução de Sinais , Transcriptoma/genética
11.
Proc Natl Acad Sci U S A ; 117(34): 20920-20925, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32788371

RESUMO

In plants, environmental stressors trigger plasma membrane depolarizations. Being electrically interconnected via plasmodesmata, proper functional dissection of electrical signaling by electrophysiology is basically impossible. The green alga Chlamydomonas reinhardtii evolved blue light-excited channelrhodopsins (ChR1, 2) to navigate. When expressed in excitable nerve and muscle cells, ChRs can be used to control the membrane potential via illumination. In Arabidopsis plants, we used the algal ChR2-light switches as tools to stimulate plasmodesmata-interconnected photosynthetic cell networks by blue light and monitor the subsequent plasma membrane electrical responses. Blue-dependent stimulations of ChR2 expressing mesophyll cells, resting around -160 to -180 mV, reproducibly depolarized the membrane potential by 95 mV on average. Following excitation, mesophyll cells recovered their prestimulus potential not without transiently passing a hyperpolarization state. By combining optogenetics with voltage-sensing microelectrodes, we demonstrate that plant plasma membrane AHA-type H+-ATPase governs the gross repolarization process. AHA2 protein biochemistry and functional expression analysis in Xenopus oocytes indicates that the capacity of this H+ pump to recharge the membrane potential is rooted in its voltage- and pH-dependent functional anatomy. Thus, ChR2 optogenetics appears well suited to noninvasively expose plant cells to signal specific depolarization signatures. From the responses we learn about the molecular processes, plants employ to channel stress-associated membrane excitations into physiological responses.


Assuntos
Membrana Celular/metabolismo , Channelrhodopsins/metabolismo , Bombas de Próton/metabolismo , Adenosina Trifosfatases/metabolismo , Proteínas de Algas/metabolismo , Channelrhodopsins/fisiologia , Chlamydomonas reinhardtii/metabolismo , Cor , Concentração de Íons de Hidrogênio , Luz , Potenciais da Membrana/fisiologia , Optogenética/métodos , Bombas de Próton/fisiologia , Rodopsina/metabolismo , Transdução de Sinais
13.
Nature ; 524(7563): 97-101, 2015 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-26083749

RESUMO

West Africa is currently witnessing the most extensive Ebola virus (EBOV) outbreak so far recorded. Until now, there have been 27,013 reported cases and 11,134 deaths. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two-year-old boy in December 2013 (ref. 2). From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission is not known and currently relies on epidemiological analysis, which may be unreliable owing to the difficulties of obtaining patient information. Here we trace the genetic evolution of EBOV in the current outbreak that has resulted in multiple lineages. Deep sequencing of 179 patient samples processed by the European Mobile Laboratory, the first diagnostics unit to be deployed to the epicentre of the outbreak in Guinea, reveals an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. Analysis of EBOV genome evolution has also benefited from a similar sequencing effort of patient samples from Sierra Leone. Our results confirm that the EBOV from Guinea moved into Sierra Leone, most likely in April or early May. The viruses of the Guinea/Sierra Leone lineage mixed around June/July 2014. Viral sequences covering August, September and October 2014 indicate that this lineage evolved independently within Guinea. These data can be used in conjunction with epidemiological information to test retrospectively the effectiveness of control measures, and provides an unprecedented window into the evolution of an ongoing viral haemorrhagic fever outbreak.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Ebolavirus/genética , Evolução Molecular , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/virologia , Filogenia , Análise Espaço-Temporal , Substituição de Aminoácidos/genética , Ebolavirus/isolamento & purificação , Feminino , Guiné/epidemiologia , Doença pelo Vírus Ebola/transmissão , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Libéria/epidemiologia , Masculino , Mali/epidemiologia , Dados de Sequência Molecular , Serra Leoa/epidemiologia
14.
Proc Natl Acad Sci U S A ; 114(18): 4822-4827, 2017 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-28416693

RESUMO

The Venus flytrap Dionaea muscipula captures insects and consumes their flesh. Prey contacting touch-sensitive hairs trigger traveling electrical waves. These action potentials (APs) cause rapid closure of the trap and activate secretory functions of glands, which cover its inner surface. Such prey-induced haptoelectric stimulation activates the touch hormone jasmonate (JA) signaling pathway, which initiates secretion of an acidic hydrolase mixture to decompose the victim and acquire the animal nutrients. Although postulated since Darwin's pioneering studies, these secretory events have not been recorded so far. Using advanced analytical and imaging techniques, such as vibrating ion-selective electrodes, carbon fiber amperometry, and magnetic resonance imaging, we monitored stimulus-coupled glandular secretion into the flytrap. Trigger-hair bending or direct application of JA caused a quantal release of oxidizable material from gland cells monitored as distinct amperometric spikes. Spikes reminiscent of exocytotic events in secretory animal cells progressively increased in frequency, reaching steady state 1 d after stimulation. Our data indicate that trigger-hair mechanical stimulation evokes APs. Gland cells translate APs into touch-inducible JA signaling that promotes the formation of secretory vesicles. Early vesicles loaded with H+ and Cl- fuse with the plasma membrane, hyperacidifying the "green stomach"-like digestive organ, whereas subsequent ones carry hydrolases and nutrient transporters, together with a glutathione redox moiety, which is likely to act as the major detected compound in amperometry. Hence, when glands perceive the haptoelectrical stimulation, secretory vesicles are tailored to be released in a sequence that optimizes digestion of the captured animal.


Assuntos
Droseraceae/fisiologia , Exocitose/fisiologia , Insetos , Transdução de Sinais/fisiologia , Animais , Droseraceae/ultraestrutura
15.
Genome Res ; 26(6): 812-25, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27197216

RESUMO

Although the concept of botanical carnivory has been known since Darwin's time, the molecular mechanisms that allow animal feeding remain unknown, primarily due to a complete lack of genomic information. Here, we show that the transcriptomic landscape of the Dionaea trap is dramatically shifted toward signal transduction and nutrient transport upon insect feeding, with touch hormone signaling and protein secretion prevailing. At the same time, a massive induction of general defense responses is accompanied by the repression of cell death-related genes/processes. We hypothesize that the carnivory syndrome of Dionaea evolved by exaptation of ancient defense pathways, replacing cell death with nutrient acquisition.


Assuntos
Droseraceae/genética , Droseraceae/citologia , Droseraceae/metabolismo , Genoma de Planta , Herbivoria , Folhas de Planta/citologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transdução de Sinais , Transcriptoma
16.
New Phytol ; 218(2): 414-431, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29332310

RESUMO

Content Summary 414 I. Introduction 415 II. Ca2+ importer and exporter in plants 415 III. The Ca2+ decoding toolkit in plants 415 IV. Mechanisms of Ca2+ signal decoding 417 V. Immediate Ca2+ signaling in the regulation of ion transport 418 VI. Ca2+ signal integration into long-term ABA responses 419 VII Integration of Ca2+ and hormone signaling through dynamic complex modulation of the CCaMK/CYCLOPS complex 420 VIII Ca2+ signaling in mitochondria and chloroplasts 422 IX A view beyond recent advances in Ca2+ imaging 423 X Modeling approaches in Ca2+ signaling 424 XI Conclusions: Ca2+ signaling a still young blooming field of plant research 424 Acknowledgements 425 ORCID 425 References 425 SUMMARY: Temporally and spatially defined changes in Ca2+ concentration in distinct compartments of cells represent a universal information code in plants. Recently, it has become evident that Ca2+ signals not only govern intracellular regulation but also appear to contribute to long distance or even organismic signal propagation and physiological response regulation. Ca2+ signals are shaped by an intimate interplay of channels and transporters, and during past years important contributing individual components have been identified and characterized. Ca2+ signals are translated by an elaborate toolkit of Ca2+ -binding proteins, many of which function as Ca2+ sensors, into defined downstream responses. Intriguing progress has been achieved in identifying specific modules that interconnect Ca2+ decoding proteins and protein kinases with downstream target effectors, and in characterizing molecular details of these processes. In this review, we reflect on recent major advances in our understanding of Ca2+ signaling and cover emerging concepts and existing open questions that should be informative also for scientists that are currently entering this field of ever-increasing breath and impact.


Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Transporte de Íons , Proteínas de Membrana Transportadoras/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo
17.
New Phytol ; 214(2): 597-606, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28042877

RESUMO

The present study was performed to elucidate the fate of carbon (C) and nitrogen (N) derived from protein of prey caught by carnivorous Dionaea muscipula. For this, traps were fed 13 C/15 N-glutamine (Gln). The release of 13 CO2 was continuously monitored by isotope ratio infrared spectrometry. After 46 h, the allocation of C and N label into different organs was determined and tissues were subjected to metabolome, proteome and transcriptome analyses. Nitrogen of Gln fed was already separated from its C skeleton in the decomposing fluid secreted by the traps. Most of the Gln-C and Gln-N recovered inside plants were localized in fed traps. Among nonfed organs, traps were a stronger sink for Gln-C compared to Gln-N, and roots were a stronger sink for Gln-N compared to Gln-C. A significant amount of the Gln-C was respired as indicated by 13 C-CO2 emission, enhanced levels of metabolites of respiratory Gln degradation and increased abundance of proteins of respiratory processes. Transcription analyses revealed constitutive expression of enzymes involved in Gln metabolism in traps. It appears that prey not only provides building blocks of cellular constituents of carnivorous Dionaea muscipula, but also is used for energy generation by respiratory amino acid degradation.


Assuntos
Aminoácidos/metabolismo , Carbono/metabolismo , Droseraceae/citologia , Droseraceae/metabolismo , Dióxido de Carbono/metabolismo , Isótopos de Carbono/metabolismo , Respiração Celular , Metaboloma , Isótopos de Nitrogênio/metabolismo , Proteínas de Plantas/metabolismo
18.
J Infect Dis ; 214(suppl 3): S250-S257, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-27638946

RESUMO

BACKGROUND: A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015. METHODS: The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively. RESULTS: The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged <15 years had the highest proportion of Ebola virus-malaria parasite coinfections. The case-fatality ratio was high in patients aged <5 years (80%) and those aged >74 years (90%) and low in patients aged 10-19 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of <5 and ≥45 years, and, among children aged 5-14 years, malaria parasite coinfection were independent determinants of a poor EVD outcome. CONCLUSIONS: Virus load, age, and malaria parasite coinfection play a role in the outcome of EVD.


Assuntos
Ebolavirus/isolamento & purificação , Epidemias , Infecções por Filoviridae/diagnóstico , Doença pelo Vírus Ebola/diagnóstico , Malária/complicações , Unidades Móveis de Saúde , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Serviços de Laboratório Clínico , Ebolavirus/genética , Feminino , Filoviridae , Infecções por Filoviridae/complicações , Infecções por Filoviridae/virologia , Guiné , Doença pelo Vírus Ebola/complicações , Doença pelo Vírus Ebola/virologia , Humanos , Lactente , Malária/parasitologia , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , Carga Viral , Adulto Jovem
19.
Med Microbiol Immunol ; 205(2): 173-83, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26475282

RESUMO

The 2014 Zaire Ebola virus (ZEBOV) outbreak in West Africa represents an international public health concern. Highly sensitive and precise diagnostic tools are needed. In the present study, we developed a ZEBOV-specific enzyme-linked immunosorbent assay (ELISA) using inactivated ZEBOV isolate Makona from March 2014. Mock antigen was used to address nonspecific binding. Specificity, reproducibility and precision were determined to measure assay performance. The ZEBOV ELISA proved to be specific (96 %), reproducible and precise (Intra-assay CV 8 %, Inter-assay CV 18 %). Using the human monoclonal antibody KZ52, we showed that the ELISA was able to detect conformation-specific antibodies. Monitoring antibody development in 29 PCR-positive EBOV disease (EVD) patients revealed seroconversion in all cases. In addition, the ELISA was used to detect ZEBOV glycoprotein (GP)-specific antibodies in a vaccinated volunteer from day 14 until 5 years post-vaccination with a VSV-ZEBOV candidate vaccine. The results demonstrate the high reproducibility, specificity and sensitivity of this newly developed ELISA, which is suitable for the detection of specific antibody responses directed against different ZEBOV proteins in EVD patients and against the ZEBOV surface glycoprotein GP in vaccinated individuals.


Assuntos
Anticorpos Antivirais/imunologia , Ebolavirus/imunologia , Ensaio de Imunoadsorção Enzimática , Doença pelo Vírus Ebola/diagnóstico , Doença pelo Vírus Ebola/imunologia , Animais , Linhagem Celular , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/normas , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Pflugers Arch ; 467(5): 1091-104, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25369776

RESUMO

Two-pore domain potassium (K2P) channels are membrane proteins widely identified in mammals, plants, and other organisms. A functional channel is a dimer with each subunit comprising two pore-forming loops and four transmembrane domains. The genome of the model plant Arabidopsis thaliana harbors five genes coding for K2P channels. Homologs of Arabidopsis K2P channels have been found in all higher plants sequenced so far. As with the K2P channels in mammals, plant K2P channels are targets of external and internal stimuli, which fine-tune the electrical properties of the membrane for specialized transport and/or signaling tasks. Plant K2P channels are modulated by signaling molecules such as intracellular H(+) and calcium and physical factors like temperature and pressure. In this review, we ask the following: What are the similarities and differences between K2P channels in plants and animals in terms of their physiology? What is the nature of the last common ancestor (LCA) of these two groups of proteins? To answer these questions, we present physiological, structural, and phylogenetic evidence that discards the hypothesis proposing that the duplication and fusion that gave rise to the K2P channels occurred in a prokaryote LCA. Conversely, we argue that the K2P LCA was most likely a eukaryote organism. Consideration of plant and animal K2P channels in the same study is novel and likely to stimulate further exchange of ideas between students of these fields.


Assuntos
Concentração de Íons de Hidrogênio , Filogenia , Canais de Potássio de Domínios Poros em Tandem/metabolismo , Potássio/metabolismo , Transdução de Sinais/fisiologia , Animais , Humanos , Plantas
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