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Pyridine Nucleotide Cycling and Control of Intracellular Redox State in Relation to Poly （ADP-Ribose） Polymerase Activity and Nuclear Localization of Glutathione during Exponential Growth of Arabidopsis Cells in Culture

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Molecular Plant 2009年第3期2卷 442-456页

作者： Till K. Pellny vittoria Locato pedro Diaz vivancos Jelena Markovic Laura De Gara Federico v. Pallardo Christine H. Foyer Plant Sciences Rothamsted Research Harpenden Hefts AL5 2 JQ UK CIR UniversitA Campus Bio-Medico V. A. Del Portillo 21 00128 Roma Italy School of Agriculture Food and Rural Development Newcastle University Newcastle upon Tyne NE1 7RU UK Depto. de Fisiologia Av. Blasco Ibanez 15 46010 Valencia Spain Dipartimento di Biologia e Patologia vegetale M E. Orabona 4 70125 Bari Italy

Pyridine nucleotides, ascorbate and glutathione are major redox metabolites in plant cells, with specific roles in cellular redox homeostasis and the regulation of the cell cycle. However, the regulation of these metabolite pools during exponential growth and their precise functions in the cell cycle remain to be characterized. The present analysis of the abundance of ascorbate, glutathione, and pyridine nucleotides during exponential growth of Arabidopsis cells in culture provides evidence for the differential regulation of each of these redox pools. Ascorbate was most abundant early in the growth cycle, but glutathione was low at this point. The cellular ascorbate to dehydroascorbate and reduced glutathione （GSH） to glutathione disulphide ratios were high and constant but the pyridine nucleotide pools were largely oxidized over the period of exponential growth and only became more reduced once growth had ceased. The glutathione pool increased in parallel with poly （ADP-ribose） polymerase （PARP） activities and with increases in the abundance of PARP1 and PARP2 mRNAs at a time of high cell cycle activity as indicated by transcriptome information. Marked changes in the intracellular partitioning of GSH between the cytoplasm and nucleus were observed. Extension of the exponential growth phase by dilution or changing the media led to increases in the glutathione and nicotinamide adenine dinucleotide, oxidized form （NAD）-plus-nicotinamide adenine dinucleotide, reduced form （NADH） pools and to higher NAD/NADH ratios but the nicotinamide adenine dinucleotide phosphate, oxidized form （NADP）-plus-nicotinamide adenine dinucleotide phosphate, reduced form （NADPH） pool sizes, and NAPD/NADPH ratios were much less affected. The ascorbate, glutathione, and pyridine nucleotide pools and PARP activity decreased before the exponential growth phase ended. We conclude that there are marked changes in intracellular redox state during the growth cycle but that redox homeostasis is maint

关键词： glutathione ascorbate Redox control cell cycle cell signaling cell redox state.

Altitude as environmental filtering influencing phylogenetic diversity and species richness of plants in tropical mountains

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Journal of Mountain Science 2023年第2期20卷 285-298页

作者： GALvÁN-CISNEROS Carlos M. vILLA pedro M. COELHO Alex J.P. CAMPOS Prímula v. MEIRA-NETO João A.A. Laboratory of Ecology and Evolution of Plants Departamento de Biologia VegetalUniversidade Federal de ViçosaViçosaMG36570-900Brazil Botany Gradute Program Universidade Federal de ViçosaViçosaMG36570-900Brazil

Elucidating how multiple factors affect biodiversity and plant community assembly is a central issue in ecology,especially in vulnerable ecosystems such as tropical *** studies are more relevant in global warming scenarios that induce the upward displacement of plant species towards reduced habitats and hostile environments in tropical *** study aimed to analyze how altitude affects taxonomic and phylogenetic diversity in plant communities of tropical ***,we tested if(i)increased altitude works as an environmental filtering promoting decreased species richness,decreased phylogenetic diversity,and increased phylogenetic clustering in these tropical mountains;and if(ii)plant communities of high altitude in tropical mountains are also result of recent diversification with plant species recently split shortening phylogenetic distances between closest related *** tested effects of altitude on species richness and phylogenetic metrics using linear mixed-effects *** Haleakala presented 114 species,Mount Kilimanjaro presented 231 species and Mount Purace presented 280 *** found an environmental filtering effect with increasing altitude causing phylogenetic clustering,decreased phylogenetic diversity and decreased species *** decreasing phylogenetic distances between closest relatives are congruent with neo-endemics,suggesting recent plant diversification in high altitudes of tropical mountains,possibly driven by geographic isolation and environmental *** of global warming should be monitored in tropical mountains focusing on distribution shifts.

关键词： Tropical mountains Global warming Environmental filtering Phylogenetic ecology Assembly rules Conservation Mountaintop vegetation

Role of Angiotensin-(1-7) on Renal Hypertrophy in Streptozotocin-Induced Diabetes Mellitus

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Pharmacology & Pharmacy 2016年第9期7卷 379-395页

作者： Dante Amato Alma R. Núñez-Ortiz José del Carmen Benítez-Flores David Segura-Cobos pedro López-Sánchez Beatriz vázquez-Cruz Laboratorio de Farmacología Unidad de Investigación Interdisciplinaria en Ciencias de la Salud y la Educación Facultad de Estudios Superiores Iztacala Universidad Nacional Autónoma de México Tlalnepantla México Laboratorio de Histología Unidad de Morfología y Función Facultad de Estudios Superiores Iztacala Universidad Nacional Autónoma de México Tlalnepantla México Sección de Estudios de Posgrado e Investigación Escuela Superior de Medicina Instituto Politécnico Nacional Ciudad de México México

Participation of angiotensin II in chronic kidney diseases including diabetic nephropathy (DN) has been extensively described. Similarly, several studies support a protective role for angiotensin-(1-7). However, other studies suggest that some of the cellular effects of angiotensin-(1-7) may be deleterious. The objective of this study was to determine the role of exogenous angiotensin-(1-7) on renal hypertrophy development in rats with streptozotocin-induced diabetes. A control group and three groups of rats with streptozotocin-induced diabetes: untreated diabetic rats, diabetic rats treated with captopril, and diabetic rats treated with angiotensin-(1-7), were studied. After two weeks of treatment, the kidneys were removed under anesthesia with pentobarbital. The kidneys were weighed and the renal cortex was separated for analysis of AT1R, TGF-β1, MASR, and ACE2 expression by western blot. Rats in the three groups with diabetes had hyperglycemia, increased food and water consumption, and higher urinary volume than control rats. Treatment with captopril or angiotensin-(1-7) reversed streptozotocin-induced renal hypertrophy, measured by kidney weight, protein/DNA ratio in renal cortex, glomerular area, or proximal tubular cells area, proteinuria, and creatinine clearance reduction. AT1R, TGF-β1, and MAS receptor expression in renal cortex of diabetic rats increased significantly as compared to controls (p

关键词： Diabetes Mellitus Streptozotocin Ang-(1-7) MAS Receptor Renal Hypertrophy

Significance of the balance between intracellular glutathione and polyethylene glycol for successful release of small interfering RNA from gold nanoparticles

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Nano Research 2015年第10期8卷 3281-3292页

作者： Mark McCully Yulan Hernandez Joao Conde pedro v. Baptista Jesus M. de la Fuente Andrew Hursthouse David Stirling Catherine C. Berry CentreforCellEngineering UniversityofGlasgowGlasgowG128QQScotlandUK InstituteofNanoscienceofAragon UniversityofZaragozaZaragoza50018Spain MassachusettsInstituteofTechnology InstituteforMedicalEngineeringandScienceHarvard-MITDivisionforHealthSciencesandTechnologyCambridgeMassachusetts02139USA UCIBIO DepartamentodeCienciasdaVidaFaculdadedeCienciaseTecnologiaUniversidadeNovadeLisboaCampusdeCaparicaCaparica2829-516Portugal InstitutodeCienciadeMaterialesdeAragon(ICMA) CSIC-UniversidaddeZaragozac/PedroCerbuna12Zaragoza50009Spain InstituteofNanoBiomedicineandEngineering KeyLaboratoryforThinFilmandMicrofabricationTechnologyoftheMinistryofEducationResearchInstituteofTranslationMedicineShanghaiJiaoTongUniversityDongchuanRoad800Shanghai200240China SchoolofScience UniversityoftheWestofScotlandPaisleyPA12BEScotlandUK

The therapeutic promise of small interfering RNAs （siRNAs） for specific gene silencing is dependent on the successful delivery of functional siRNAs to the cytoplasm. Their conjugation to an established delivery platform, such as gold nanoparticles, offers tremendous potential for treating diseases and advancing our understanding of cellular processes. Their success or failure is dependent on both the uptake of the nanoparticles into the cells and subsequent intracellular release of the functional siRNA. In this study, utilizing gold nanoparticle siRNA-mediated delivery against C-MYC, we aimed to determine if we could achieve knockdown in a cancer cell line with low levels of intracellular glutathione, and determine the influence, if any, of polyethylene glycol （PEG） ligand density on knockdown, with a view to determining the optimal nanoparticle design to achieve C-MYC knockdown. We demonstrate that, regardless of the PEG density, knockdown in cells with relatively low glutathione levels can be achieved, as well as the possible effect of steric hindrance of PEG on the availability of the siRNA for cleavage in the intracellular environment. Gold nanoparticle uptake was demonstrated via transmission electron microscopy and mass spectroscopy, while knockdown was determined at the protein and physiological levels （cells in S-phase） by in-cell westerns and BrdU incorporation, respectively.

关键词： gold nanoparticles PEG glutathione siRNA drug delivery

Improving surface integrity when drilling CFRPs and Ti-6Al-4v using sustainable lubricated liquid carbon dioxide

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Chinese Journal of Aeronautics 2023年第7期36卷 129-146页

作者： In˜igo RODRIGUEZ pedro Jose´ARRAZOLA Mikel CUESTA Luka STERLE Franci PUSˇAvEC Faculty of Engineering Mondragon UnibertsitateaArrasate-Mondragon 20500Spain Faculty of Mechanical Engineering University of LjubljanaLjubljana 1000Slovenia

In the quest for decreasing fuel consumption and resulting gas emissions in the aeronautic sector,lightweight materials such as Carbon Fiber Reinforced Polymers(CFRPs)and Ti-6Al-4v alloys are being *** materials,with excellent weight-to-strength ratios,are widely used for structural applications in aircraft *** date,several studies have been published showing that the use of metalworking fluids(MWFs),special tool geometries,or advanced machining techniques is required to ensure a surface quality that meets aerospace component *** MWFs pose a number of environmental and worker health hazards and also degrade the mechanical properties of CFRPs due to water absorption in the ***,a transition to more environmentally friendly cooling/lubrication techniques that prevent moisture problems in the composite is *** research shows that lubricated LCO_(2) is a viable option to improve the quality of drilled CFRP and titanium aerospace components compared to dry machining,while maintaining clean work *** results show that the best combination of tool geometry and cooling conditions for machining both materials is drilling with Brad point drills and lubricated LCO_(2).Drilling under these conditions resulted in a 90%improvement in fiber pullout volume compared to dry machined CFRP *** addition,a 33% reduction in burr height and a 15% improvement in surface roughness were observed compared to dry drilling of titanium.

关键词： Carbon fibers Cryogenics Green manufacturing Machining Solid lubricants Surface morphology Titanium alloys

Regulation of floral senescence in Arabidopsis by coordinated action of CONSTANS and jasmonate signaling

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Molecular Plant 2022年第11期15卷 1710-1724页

作者： Gloria Serrano-Bueno pedro de los Reyes Andrea Chini Gabriel Ferreras-Garrucho víctor Sánchez de Medina-Hernández Marta Boter Roberto Solano Federico valverde Plant Development Group Institute for Plant Biochemistry and PhotosynthesisCSIC-Universidad de Sevilla41092 SevillaSpain Department of Plant Molecular Genetics Centro Nacional de BiotecnologíaCSIC28049 MadridSpain Crop Science Centre University of CambridgeCambridge CB3 OLE CambridgeUK Gregor Mendel Institute(GMI) Austrian Academy of SciencesVienna BioCenter(VBC)ViennaAustria

In Arabidopsis,photoperiodic flowering is controlled by the regulatory hub gene CONSTANS(CO),whereas floral organ senescence is regulated by the jasmonates(JAs).Because these processes are chronologically ordered,it remains unknown whether there are common regulators of both *** this study,we discovered that CO protein accumulates in Arabidopsis flowers after floral induction,and it displays a diurnal pattern in floral organs different from that in the *** observed that altered CO expression could affect flower senescence and abscission by interfering with JA response,as shown by petal-specific transcriptomic analysis as well as CO overexpression in JA synthesis and signaling *** found that CO has a ZIM(ZINC-FINGER INFLORESCENCE MERISTEM)like domain that mediates its interaction with the JA response repressor JAZ3(jasmonate ZIM-domain 3).Their interaction inhibits the repressor activity of JAZ3,resulting in activation of downstream transcription factors involved in promoting flower ***,we showed that CO,JAZ3,and the E3 ubiquitin ligase COI1(Coronatine Insensitive 1)could form a protein complex in planta,which promotes the degradation of both CO and JAZ3 in the presence of *** together,our results indicate that CO,a key regulator of photoperiodic flowering,is also involved in promoting flower senescence and abscission by augmenting JA signaling and *** propose that coordinated recruitment of photoperiodic and JA signaling pathways could be an efficient way for plants to chronologically order floral processes and ensure the success of offspring production.

关键词： CONSTANS flower senescence jasmonic acid

Delving into the variations in tree species composition and richness across south american subtropical atlantic and Pampean forests

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Journal of Plant Ecology 2015年第3期8卷 242-260页

作者： Ary T.Oliveira-Filho Jean C.Budke João A.Jarenkow pedro v.Eisenlohr Danilo R.M.Neves Departamento de Botânica Instituto de Ciências BiológicasUniversidade Federal de Minas GeraisAv.Antônio Carlos6627Belo HorizonteMinas Gerais31270-901Brazil Departamento de Ciências Biológicas Universidade Regional Integrada do Alto Uruguai e das MissõesAv.Sete de Setembro1621ErechimRio Grande do Sul99700-000Brazil Departamento de Botânica Instituto de BiociênciasUniversidade Federal do Rio Grande do SulAv.Bento Gonçalves9500Porto AlegreRio Grande do Sul91501-970Brazil Royal Botanic Garden Edinburgh Inverleith RowEdinburghEH35LRUK

Aims We analyse here the variations in species composition and richness and the geographic ranges of the tree species occurring in south american subtropical atlantic and Pampean *** goals were to assess(i)the floristic consistency of usual classifications based on vegetation physiognomy,climate and elevation;(ii)the leading role of temperature-related variables on the variations in species composition and richness;(iii)the predominance of species with tropical-subtropical ranges,possibly as a result of forest expansion over grasslands after the last glacial maximum(LGM);(iv)the restriction of most subtropical endemics to stressful habitats as a possible result of past forest refuges during the *** The region was defined by the Tropic of Capricorn to the north,the rio de la Plata to the south,the atlantic shoreline to the east and the catchment areas of the upper Paranáand uruguay rivers to the *** analyses,multiple regression modelling and variance partition analyses were performed on a database containing 63994 occurrence records of 1555 tree species in 491 forest sites and 48 environmental *** species were also classified according to their known geographic *** Findingsa main differentiation in species composition and richness was observed between the eastern windward coastlands(rain and cloud forests)and western leeward hinterlands(Araucaria and semi-decid-uous forests).Pre-defined forest types on both sides were consistent with variations in tree species composition,which were significantly related to both environmental variables and spatial proximity,with extremes of low temperature playing a chief *** species rich-ness declined substantially towards the south and also from rain to seasonal forests and towards the highland summits and sandy *** richness was significantly correlated with both minimum temperature and actual *** 91%of the subtropical flora is shared with the

关键词： distribution patterns endemic species floristic connections macro-scale species richness spatial and climatic predictors subtropical forests

Geometry-Guided Rendering Optimization

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Geometry-Guided Rendering Optimization

RNA Polymerase v Functions in Arabidopsis Interphase Heterochromatin Organization Independently of the 24-nt siRNA-Directed DNA Methylation Pathway

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作者： pedro v.Sander Department of Computer Science and Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong

Rendering complex 3D scenes efficiently is one of the most fundamental problems in computer *** has applications ranging from architecture,visualization,animated films, computer games,and medical imaging,among many *** ever evolving GPU hardware capabilities,new research opportunities arise to take advantage of the GPU in order to further optimize rendering speed.

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Molecular Plant 2009年第4期2卷 700-710页

作者： Olga Pontes pedro Costa-Nunes Paul vithayathil Craig S. Pikaard Biology Department Washington University 1 Brookings Drive St Louis MO 63130 USA

In Arabidopsis, pericentromeric repeats, retroelements, and silenced rRNA genes are assembled into heterochromatin within nuclear structures known as chromocenters. The mechanisms governing higher-order heterochromatin organization are poorly understood but 24-nt small interfering RNAs （siRNAs） are known to play key roles in heterochromatin formation. Nuclear RNA polymerase Iv （Pol Iv）, RNA-DEPENDENT RNA POLYMERASE 2 （RDR2）, and DICER-LIKE 3 （DCL3） are required for biogenesis of 24-nt siRNAs that associate with ARGONAUTE 4 （AGO4）. Nuclear RNA polymerase v （Pol v） collaborates with DRD1 （DEFICIENT IN RNA-DEPENDENT DNA METHYLATION 1） to generate transcripts at heterochromatic loci that are hypothesized to bind to siRNA-AGO4 complexes and subsequently recruit the de-novo DNA methylation and/or histone modifying machinery. Here, we report that decondensation of the major pericentromeric repeats and depletion of the heterochromatic mark histone H3 lysine 9 dimethylation at chromocenters occurs specifically in pol v and drdl mutants. Disruption of pericentromeric repeats condensation is coincident with transcriptional reactivation of specific classes of pericentromeric 180-bp repeats. We further demonstrate that Pol v functions independently of Pol Iv, RDR2, and DCL3-mediated siRNA production to affect interphase heterochromatin organization, possibly by involving RNAs that recruit structural or chromatin-modifying proteins.

关键词： RNA polymerase v RNA-directed DNA methylation heterochromatin centromere gene expression.