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Targeting of Pollen Tubes to Ovules Is Dependent on Nitric Oxide （NO） Signaling

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Molecular Plant 2008年第4期1卷 703-714页

作者： ana margarida Prado Renato Colaco Nuno Moreno ana Catarina Silva Jose A. Feijo Instituto Gulbenkian de Ciencla Centro de Blologia do Desenvolvimento PT-2780-156 Oeiras Portugal Universidade de Lisboa Faculdade de Clencias Dept Biologia Vegetal Campo Grande Ed.C2. PT-1749-016 Lisboa Portugal

The guidance signals that drive pollen tube navigation inside the pistil and micropyle targeting are still, to a great extent, unknown. Previous studies in vitro showed that nitric oxide （NO） works as a negative chemotropic cue for pollen tube growth in lily （Lilium Iongiflorum）. Furthermore, Arabidopsis thaliana Atnosl mutant plants, which show de- fective NO production, have reduced fertility. Here, we focus in the role of NO in the process of pollen-pistil communication, using Arabidopsis in-vivo and lily semi-vivo assays. Cross-pollination between wild-type and Atnosl plants shows that the mutation affects the pistil tissues in a way that is compatible with abnormal pollen tube guidance. Moreover, DAF- 2DA staining for NO in kanadi floral mutants showed the presence of NO in an asymmetric restricted area around the micropyle. The pollen-pistil interaction transcriptome indicates a time-course-specific modulation of transcripts of AtNOS1 and two Nitrate Reductases （nrl and nr2）, which collectively are thought to trigger a putative NO signaling pathway. Semivivo assays with isolated ovules and lily pollen further showed that NO is necessary for micropyle targeting to occur. This evidence is supported by CPTIO treatment with subsequent formation of balloon tips in pollen tubes facing ovules. Activation of calcium influx in pollen tubes partially rescued normal pollen tube morphology, suggesting that this pathway is also dependent on Ca^2＋ signaling. A role of NO in modulating Ca^2＋ signaling was further substantiated by direct imaging the cytosolic free Ca^2＋ concentration during NO-induced re-orientation, where two peaks of Ca^2＋ occur--one during the slowdown/stop response, the second during re-orientation and growth resumption. Taken together, these results provide evidence for the participation of NO signaling events during pollen-pistil interaction. Of special relevance, NO seems to directly affect the targeting of pollen tubes to the ovule＇s micropyle by modu

关键词： pollen tubes NO fertilization guidance calcium signaling

Nitric Oxide： A Multitasked Signaling Gas in Plants

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Molecular Plant 2015年第4期8卷 506-520页

作者： Patricia Domingos ana margarida Prado Aloysius Wong Christoph Gehring Jose A. Feijo Instituto Gulbenkian de Ciencia P-2780-156 Oeiras Portugal Division of Biological and Environmental Sciences and Engineering 4700 King Abdullah University of Science and Technology Thuwa123955-6900 Kingdom of Saudi Arabia Department of Cell Biology and Molecular Genetics University of Maryland 0118 BioScience Research Building College Park MD 20742-5815 USA

Nitric oxide （NO） is a gaseous reactive oxygen species （ROS） that has evolved as a signaling hormone in many physiological processes in animals. In plants it has been demonstrated to be a crucial regulator of development, acting as a signaling molecule present at each step of the plant life cycle. NO has also been implicated as a signal in biotic and abiotic responses of plants to the environment. Remarkably, despite this plethora of effects and functional relationships, the fundamental knowledge of NO production, sensing, and transduction in plants remains largely unknown or inadequately characterized. In this review we cover the current understanding of NO production, perception, and action in different physiological sce- narios. We especially address the issues of enzymatic and chemical generation of NO in plants, NO sensing and downstream signaling, namely the putative cGMP and Ca^2＋ pathways, ion-channel activity modulation, gene expression regulation, and the interface with other ROS, which can have a profound effect on both NO accumulation and function. We also focus on the importance of NO in cell-cell communication during developmental processes and sexual reproduction, namely in pollen tube guidance and embryo sac fertilization, pathogen defense, and responses to abiotic stress.

关键词： nitric oxide (NO) reactive oxygen species (ROS) plant sexual reproduction cell communication pollen

“Love Is Strong, and You＇re so Sweet”： JAGGER Is Essential for Persistent Synergid Degeneration and Polytubey Block in Arabidopsis thaliana

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Molecular Plant 2016年第4期9卷 601-614页

作者： ana Marta Pereira margarida Sofia Nobre Sara Cristina Pinto ana Lucia Lopes Mario Luis Costa Simona Masiero Silvia Coimbra Departamento de Biologia Faculdade de Ciencias da Universidade do Porto Rua do Campo Alegre 4169-007 Porto Portugal Plant Functional Genomics Group Biosystems and Integrative Sciences Institute (BiolSI) 4169-007 Porto Portugal Dipartimento di BioScienze Universita degli Studi di Milano 20133 Milan Italy Present address: Institute of Plant Biology and ZUrich-Basel Plant Science Center University of ZUrich Zolikerstrasse 107 8008 Zurich Switzerland

Successful double fertilization and subsequent seed development in flowering plants requires the delivery of two sperm cells, transported by a pollen tube, into the embryo sac of an ovule. The embryo sac cells tightly control synergid cell death, and as a result the polyspermy block. Arabinogalactan proteins are highly glycosylated proteins thought to be involved in several steps of the reproductive process. We show that JAGGER, Arabinogalactan Protein 4, is an important molecule necessary to prevent the growth of multiple pollen tubes into one embryo sac in Arabidopsis thaliana. In jagger, an AGP4 knockout mutant, the pistils show impaired pollen tube blockage as a consequence of the survival of the persistent synergid. JAGGER seems to be involved in the signaling pathway that leads to a blockage of pollen tube attraction. Our results shed light on the mechanism responsible for preventing polyspermy in Arabidopsis and for safe- guarding successful fertilization of all ovules in one pistil, ensuring seed set and the next generation.

关键词： Polytubey persistent synergid arabinogalactan proteins polyspermy

The role of mouse models in colorectal cancer research—The need and the importance of the orthotopic models

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Animal Models and Experimental Medicine 2020年第1期3卷 1-8页

作者： Rui C.Oliveira ana margarida Abrantes JoseGuilherme Tralhao Maria Filomena Botelho Biophysics Unit Faculty of MedicineUniversity of CoimbraCoimbraPortugal Pathology Department University Hospital(CHUC)CoimbraPortugal Centre of Investigation on Environment Genetics and Oncobiology(CIMAGO)CoimbraPortugal Surgery A Department Faculty of MedicineUniversity Hospital(CHUC)CoimbraPortugal

Colorectal cancer is a worldwide health burden,with high incidence and mortality,especially in the advanced stages of the *** models are very important and valuable to discover and validate early and specific biomarkers as well as new therapeutic *** order to accomplish that,the animal models must replicate the clinical evolution of the disease in all of its *** this article,we review the existent mouse models,with their strengths and weaknesses in the replication of human cancer disease progression,with major focus on orthotopic models.

关键词： colorectal cancer mouse model orthotopic model

Ileal intussusception due to a parasite egg: A case report

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World Journal of Gastroenterology 2014年第36期20卷 13191-13194页

作者： José Pedro Pinto Agostinho Cordeiro ana margarida Ferreira Conceio Antunes Patrícia Botelho ana Joo Rodrigues Pedro Leo Department of General Surgery Hospital of Braga 2242 Apartado Portugal Servi?o de anatomia Patológica Hospital de Braga 2242 Apartado Portugal Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Braga 2242 Apartado Portugal ICVS/3B’s-PT Government Associate Laboratory Braga/Guimar?es 2242 Apartado Portugal

Ileal intussusception is the invagination of the small intestine within itself and accounts for 1% of cases of acute obstruction. However, physicians do not initially consider intussusception as a possible diagnosis of obstruction due to its rarity in adults. Herein, we report the case of a 22-year-old male who was admitted to the Emergency Department with continuous abdominal pain. Ultrasonography and computed tomography revealed an ileal intussusception. The patient underwent surgical removal of the segment of the small bowel. Unexpectedly, pathology revealed that the invagination occurred due to a parasite egg, with features suggestive of Schistosoma species. Schistosomiasis, although considered a parasitic disease in tropical countries, is not absent from Europe and though it is highly improbable, it may be responsible for cases of intussusception in adults.

关键词： Ileal intussusception Parasite egg Bowel obstruction Schistosoma Abdominal pain

Intra-urban variation in tuberculosis and community socioeconomic deprivation in Lisbon metropolitan area:a Bayesian approach

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Infectious Diseases of Poverty 2022年第2期11卷 92-92页

作者： Olena Oliveira ana Isabel ribeiro Raquel Duarte margarida Correia‑Neves Teresa Rito Life and Health Sciences Research Institute(ICVS) School of MedicineUniversity of Minho4710‑057 BragaPortugal 不详

Background:Multidrug resistant tuberculosis(MDR-TB)is a recognized threat to global eforts to TB control and remains a priority of the National Tuberculosis ***,social determinants and socioeconomic dep‑rivation have since long been associated with worse health and perceived as important risk factors for *** study aimed to analyze the spatial distribution of non-MDR-TB and MDR-TB across parishes of the Lisbon metropolitan area of Portugal and to estimate the association between non-MDR-TB and MDR-TB and socioeconomic ***:In this study,we used hierarchical Bayesian spatial models to analyze the spatial distribution of notifcation of non-MDR-TB and MDR-TB cases for the period from 2000 to 2016 across 127 parishes of the seven municipalities of the Lisbon metropolitan area(Almada,Amadora,Lisboa,Loures,Odivelas,Oeiras,Sintra),using the Portuguese TB Surveillance System(SVIG-TB).In order to characterise the populations,we used the European Deprivation Index for Portugal(EDI-PT)as an indicator of poverty and estimated the association between non-MDR-TB and MDR-TB and socioeconomic ***:The notifcation rates per 10,000 population of non-MDR TB ranged from 18.95 to 217.49 notifcations and that of MDR TB ranged from 0.83 to *** identifed 54 high-risk areas for non-MDR-TB and 13 high-risk areas for *** in the third[relative risk(RR)=1.281,95% credible interval(CrI):1.021-1.606],fourth(RR=1.786,95%CrI:1.420-2.241)and ffth(RR=1.935,95%CrI:1.536-2.438)quintile of socioeconomic deprivation presented higher non-MDR-TB notifcations *** in the fourth(RR=2.246,95%CrI:1.374-3.684)and ffth(RR=1.828,95%CrI:1.049-3.155)quintile of socioeconomic deprivation also presented higher MDR-TB notifcations ***:We demonstrated signifcant heterogeneity in the spatial distribution of both non-MDR-TB and MDRTB at the parish level and we found that socioeconomically disadvantaged parishes are disproportionall

关键词： Tuberculosis Multidrug-resistant tuberculosis Bayesian Spatial analysis Socioeconomic deprivation

Network of GRAS transcription factors in plant development,fruit ripening and stress responses

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Horticulture Research 2023年第12期10卷 286-303页

作者： Catarina Neves Beatriz ribeiro Rute Amaro Jesús Expósito Jérôme Grimplet ana margarida Fortes BioISI-Biosystems and Integrative Sciences Institute Faculty of SciencesUniversity of LisbonCampo Grande1749-016 LisboaPortugal Centro de Investigación y Tecnología Agroalimentaria de Aragón(CITA) Departamento de Ciencia VegetalGobierno de AragónAvda.Montañana 93050059 ZaragozaSpain Instituto Agroalimentario de Aragón-IA2(CITA-Universidad de Zaragoza) Calle Miguel Servet 17750013 ZaragozaSpain

The plant-specific family of GRAS transcription factors has been wide implicated in the regulation of transcriptional reprogramming associated with a diversity of biological functions ranging from plant development processes to stress *** analyses of GRAS transcription factors supported by in silico structural and comparative analyses are emerging and clarifying the regulatory networks associated with their biological *** this review,a detailed analysis of GRAS proteins’structure and biochemical features as revealed by recent discoveries indicated how these characteristics may impact subcellular location,molecular mechanisms,and *** issues associated with GRAS classification into different subfamilies in diverse plant species even in the presence of robust genomic resources are discussed,in particular how it affects assumptions of biological *** into the mechanisms driving evolution of this gene family and how genetic and epigenetic regulation of GRAS contributes to subfunctionalization are ***,this review debates challenges and future perspectives on the application of this complex but promising gene family for crop improvement to cope with challenges of environmental transition.

关键词： function GRAS plant

Efflux Pumps Modulation in Colorectal Adenocarcinoma Cell Lines: The Role of Nuclear Medicine

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Journal of Cancer Therapy 2011年第3期2卷 408-417页

作者： Joao Casalta-Lopes ana margarida Abrantes Mafalda Laranjo Joana Rio ana Cristina Goncalves Barbara Oliveiros ana Bela Sarmento-ribeiro Maria Filomena Botelho Biophysics Unit IBILIFaculty of MedicineUniversity of CoimbraCoimbraPortugal Centre of Investigation on Cancer Envi-ronmentGenetics and OncobiologyFaculty of MedicineUniversity of CoimbraCoimbraPortugal Institute of Nuclear Sciences Applied to Health University of CoimbraCoimbraPortugal Applied Molecular Biology Unit Faculty of MedicineUniversity of CoimbraCoimbraPortugal.

Introduction: Multidrug resistance (MDR) is one of the major problems of chemotherapy. Overexpression of efflux pumps, such as P-glycoprotein (Pgp), multiple resistance-related protein 1 (MRP-1) and lung resistance protein (LRP) can lead to MDR. Verapamil and L-buthionine-sulfoximine (BSO) are two modulators of these proteins. This study aims to compare 99mTc-Sestamibi transport kinetics in human colorectal adenocarcinoma cell lines, in the presence and absence of the MDR modulators verapamil and BSO. Material and Methods: MDR proteins expression was evaluated in sensitive (WiDr) and resistant (LS1034) human colorectal adenocarcinoma cell lines. Intracellular and plasma membrane Pgp and MRP1, and LRP expression was analyzed by flow-cytometry and western blot. Cellular transport kinetics was assessed using 99mTc-Sestamibi. MDR modulation was evaluated though retention studies in resistant cells after incubation with the modulators. Results: Pgp expression was significantly higher (p≤0.001) in resistant cells. These results were confirmed by western blot analysis. 99mTc-Sestamibi uptake and retention percentage were significantly higher (p99mTc-Sestamibi, there were differences among the MDR modulators used (p99mTc-Sestamibi could indicate MDR phenotype in colorectal adenocarcinoma cells. As the modulators used showed a reversion of the retention profile only for the first minutes, their administration should occur immediately before the administration of cytotoxic drugs.

关键词： Multidrug Resistance P-Glycoprotein Multidrug Resistance-Associated Protein 1 Major Vault Protein

Understanding plant drought resistance in a Mediterranean coastal sand dune ecosystem:differences between native and exotic invasive species

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Journal of Plant Ecology 2018年第1期11卷 26-38页

作者： Cristina Antunes ana Júlia Pereira Patrícia Fernandes margarida Ramos Lia Ascensão Otília Correia Cristina Máguas Centre for Ecology Evolution and Environmental ChangesFaculdade de CiênciasUniversidade de LisboaCampo Grande1749-016 LisboaPortugal PPG-Ecologia Instituto de BiologiaCP 6109Universidade Estadual de Campinas-UNICAMP13083-970 CampinasSão PauloBrazil SPBotânica-Botanical Society of Portugal Travessa do Jardim 3A-dos-Potes2615-018 Alverca do RibatejoPortugal CESAM-Centre for Environmental and Marine Studies Faculdade de Ciências-CBVUniversidade de Lisboa1749-016 LisboaPortugal

Aims Mediterranean coastal dunes are habitats of great conservation interest,with a distinctive and rich *** the last century,Acacia spp.,native from Australia,have been introduced in Portugal,with the objective of stabilizing sand dunes,and since have become dominant in numerous sand dune *** invasion process led to the reduction of native plant species richness,changed soil characteristics and modified habitat’s microclimatic *** aim of this research was to typify and compare,in Mediterranean sand dune ecosystems,the ecophysiological responses to drought of Helichrysum italicum and Corema album,two native species,and Acacia longifolia,an exotic invasive *** addressed the following specific objectives:(i)to com-pare water relations and water use efficiencies,(ii)to evaluate water stress,(iii)to assess water use strategies and water sources used by plants and(iv)to evaluate the morphological adaptations at leaf and phyllode *** In order to obtain an integrative view of ecophysiological patterns,water relations and performance measuring methods have been applied:predawn(ψPD)and midday(ψMD)water potential,chloro-phyll a fluorescence,oxygen isotopic composition of xylem,rain and groundwater(δ18O)and leaf carbon isotopic discrimination(Δ13C).The leaf characteristics of the three species,as well as the histochemistry of non-glandular trichome cell walls,were also studied to identify morpho-traits related to drought *** Findings The results support our initial hypothesis:although *** clearly possesses a degree of resistance to water stress,such ability is provided by a different water strategy,when compared to native *** relied on morphological adaptations to restrict water loss,whereas the invasive species adjusted the water uptake as a way to balance their limited ability of restricting water *** corroborate that woody native species(i)have a conservative water-saving strategy an

关键词： ecophysiology water use strategy leaf morphology Acacia longifolia Corema album Helichrysum italicum