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A Light-Independent Allele of Phytochrome B Faithfully Recapitulates Photomorphogenic Transcriptional Networks

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Molecular Plant 2009年第1期2卷 166-182页

作者： Wei Hu Yi-Shin Su J. Clark Lagarias Department of Molecular and Cellular Biology College of Biological Sciences University of California Davis CA 95616 USA present address: Carnegie institution of Washington -Department of Plant Biology Stanford CA 94305 USA

Dominant gain-of-function alleles of Arabidopsis phytochrome B were recently shown to confer lightindependent, constitutive photomorphogenic （cop） phenotypes to transgenic plants （Su and Lagarias, 2007）. In the present study, comparative transcription profiling experiments were performed to assess whether the pattern of gene expression regulated by these alleles accurately reflects the process of photomorphogenesis in wild-type Arabidopsis. Whole- genome transcription profiles of dark-grown phyAphyB seedlings expressing the Y^276H mutant of phyB （YHB） revealed that YHB reprograms about 13% of the Arabidopsis transcriptome in a light-independent manner. The YHB-regulated transcriptome proved qualitatively similar to but quantitatively greater than those of wild-type seedlings grown under 15 or 50 μmol m^-2 m^-1 continuous red light （Rc）. Among the 2977 genes statistically significant two-fold （SSTF） regulated by YHB in the absence of light include those encoding components of the photosynthetic apparatus, tetrapyrrole/pigment biosynthetic pathways, and early light-responsive signaling factors. Approximately 80% of genes SSTF regulated by Rc were also YHB-regulated. Expression of a notable subset of 346 YHB-regulated genes proved to be strongly attenuated by Rc, indicating compensating regulation by phyC-E and/or other Rc-dependent processes. Since the majority of these 346 genes are regulated by the circadian clock, these results suggest that phyA- and phyB-independent light signaling pathway（s） strongly influence clock output. Together with the unique plastid morphology of dark-grown YHB seedlings, these analyses indicate that the YHB mutant induces constitutive photomorphogenesis via faithful reconstruction of phyB signaling pathways in a light-independent fashion.

关键词： light signaling signal transduction transcriptome analysis photomorphogenesis Arabidopsis phytochrome.

Expression, Imprinting, and Evolution of Rice Homologs of the Polycomb Group Genes

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Molecular Plant 2009年第4期2卷 711-723页

作者： Ming Luo Damien Platten Abed Chaudhury W.J. Peacock Elizabeth S. Dennis CSIRO Plant Industry GPO BOX 1600 ACT 2601 Australia present address: Vitagrain Uttara Model Town Dhaka Bangladesh present address: IRRI Los Banos Laguna 4031 Philippines

Polycomb group proteins （PcG） play important roles in epigenetic regulation of gene expression. Some core PeG proteins, such as Enhancer of Zeste （E（z））, Suppressor of Zeste （12）（Su（z）12）, and Extra Sex Combs （ESC）, are conserved in plants. The rice genome contains two E（z）-Iike genes, OsiEZ1 and OsCLF, two homologs of Su（z）12, OsEMF2a and OsEMF2b, and two ESC-like genes, OsFIE1 and OsFIE2. OsFIE1 is expressed only in endosperm; the maternal copy is expressed while the paternal copy is not active. Other rice PcG genes are expressed in a wide range of tissues and are not imprinted in the endosperm. The two E（z）-Iike genes appear to have duplicated before the separation of the dicots and monocots; the two homologs of Su（z）12 possibly duplicated during the evolution of the Gramineae and the two ESC- like genes are likely to have duplicated in the ancestor of the grasses. No homologs of the Arabidopsis seed-expressed PcG genes MEA and FIS2 were identified in the rice genome. We have isolated T-DNA insertion lines in the rice homologs of three PcG genes. There is no autonomous endosperm development in these T-DNA insertion lines. One line with a T-DNA insertion in OsEMF2b displays pleiotropic phenotypes including altered flowering time and abnormal flower organs, suggesting important roles in rice development for this gene.

关键词： Polycomb group protein pseudograin imprinting development evolution panicle.

Exciton fine structure in twisted transition metal dichalcogenide heterostructures

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npj Computational Materials 2023年第1期9卷 417-423页

作者： Sudipta Kundu Tomer Amit H.R.Krishnamurthy Manish Jain Sivan Refaely-Abramson Centre for Condensed Matter Theory Department of PhysicsIndian Institute of ScienceBangalore 560012India Department of Molecular Chemistry and Materials Science Weizmann Institute of ScienceRehovot 7610001Israel present address:Department of Materials Science and Engineering Stanford UniversityStanfordCA 94305USA

Moirésuperlattices of transition metal dichalcogenide(TMD)heterostructures give rise to rich excitonic phenomena associated with the interlayer twist *** calculations of excitons in such systems are typically based on model moirépotentials that mitigate the computational ***,predictive understanding of the electron-hole coupling dominating the excitations is crucial to realize the twist-induced modifications of the optical selection *** this work,we use many-body perturbation theory to evaluate the relation between twist angle and exciton properties in TMD *** present an approach for unfolding excitonic states from the moiréBrillouin zone onto the separate-layer *** this method to a large-angle twisted MoS^(2)/MoSe^(2) bilayer,we find that the optical spectrum is dominated by mixed electron–hole transitions with different momenta in the separate monolayers,leading to unexpected hybridization between interlayer and intralayer *** findings offer a design pathway for exciton layer-localization in TMD heterostructures.

关键词： twisted twist transition

Occupancy of avian foraging guilds in soybean fields and borders in Entre Ríos, Argentina: responses to vegetation structure and prey resources

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Avian Research 2020年第4期11卷 398-411页

作者： Andrea P.Goijman Michael J.Conroy Vanina D.Varni Jeffrey J.Thompson María Elena Zaccagnini Instituto de Recursos Biológicos CIRNInstituto Nacional de Tecnología Agropecuaria(CNIA-INTA)HurlinghamBuenos AiresArgentina D.B.Warnell School of Forestry and Natural Resources University of GeorgiaAthensGA 30602USA present address:Athens GAUSA present address:Laboratorio de Genómica Ecológica y Evolutiva IrapuatoGtoMéxico present address:Guyra Paraguay-CONACYT Av.Cnel.Carlos BóvedaParque Ecológico Capital-Viñas CuéAsunciónParaguay present address:Instituto Saite AsunciónParaguay present address:The Ronin Institute MontclairNJUSA present address:Instituto Nacional de Tecnología Agropecuaria(INTA) CABAArgentina

Background:Reconciling agriculture and biodiversity conservation is a challenge given the growing demand for agricultural *** recent decades,Argentina has witnessed agricultural expansion and intensification affecting biodiversity and associated ecosystem *** agroecosystems,the level of habitat quality is critical for birds,and may depend on vegetation structure,availability of invertebrate prey,and the use of *** the relationship between vegetation structure and avian occurrence has been widely studied,to our knowledge,there are no studies that also incorporate prey availability throughout the cycle of soybean crops in *** estimated and predicted the effects of land cover and temporal variation on the occurrence of avian foraging guilds in Entre Ríos,Argentina,in order to guide management related to potential ecosystem services provided by *** also estimated temporal effects of vegetation structure and insecticides on the main arthropod orders consumed by birds to evaluate prey ***:We conducted bird and arthropod surveys for 2 years along transects located in 20 randomly selected soybean fields(N=60)and their adjacent borders(N=78)throughout the crop growing season,in four *** estimated avian occupancy,accounting for imperfect detection,and arthropod counts fitting generalized linear mixed ***:The number of native trees in field borders positively influenced the occurrence of most bird species,mainly *** foliage gleaners,also were positively affected by grass *** and aerial foragers were weakly affected by distance to forest and native *** general,the availability of invertebrates to birds was highest during the third *** counts in borders were greater during the last three crop stages than during the pre-sowing ***:We found that with 10 to 15 native tree species in borders,coupled with a complex vegetation structure w

关键词： Agriculture Birds Ecosystem services Insecticide Insectivores Invertebrates Management Native trees Occurrence

Geochronology and geochemistry of the W-Mo-ore-related granitic rocks from eastern Ningzhen,lower Yangtze river belt,eastern China

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Acta Geochimica 2022年第2期41卷 288-306页

作者： Fangyue Wang Yongjie Guo Haiyang Yan Haiou Gu He Sun Can Ge present address:School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China Ore Deposit and Exploration Center Hefei University of TechnologyHefei 230009China Anhui Institute of Geological Survey(Anhui Institute of Geological Sciences) Hefei 230001China

Here we present zircon U–Pb–Hf and wholerock major and trace element studies of eastern Ningzhen W-Mo-ore-related magmatic rocks,Yushan and Longwangshan granitic rocks,to constrain their form timing,magma sources,and tectonic *** results showed that the two plutons were formed in the Early Cretaceous with;Pb/;U ages of 107.8±1.2 and 105.2±1.5 Ma(;Pb/;U),*** trapped/residual zircons are mainly distributed in 2.0–2.5 *** two intrusions are characterized by high silicon(68.60–73.99%),high aluminum(13.56–15.02%),high Mg#(47–55),high Sr,Sr/Y,LaN/YN,and low Yb,falling into high Mg#adakitic rock *** zirconεHf(t)values of the two intrusions range from-24.8 to-13.2,indicating an ancient continental crust in their magma *** average Ti-inzircon temperature is 689°C,slightly higher than those of other high-Mg adakitic rocks in the lower Yangtze River belt,but lower than those of high-Mg adakitic rocks in the Southern Tanlu Fault(STLF).Zircon Ce;/Ce;show low oxygen fugacity(LWS-1:3–400,average 92;sample ZYS-4:9–382,average 93).These geochemical features indicate a thickened lower continental crust in the Eastern Ningzhen region in a subduction *** the geochemical characteristics of the eastern Ningzhen to the western Ningzhen and other areas in the Lower Yangtze River Metallogenic Belt(LYRMB)and the high-Mg ore-barren adakitic rocks of the STLF,we propose that the magmatic rocks from eastern Ningzhen may be mainly from a thickened lower continental crust that hybridized with a very small part of mantle sources,while the west Ningzhen magmatic rocks may have experienced a higher degree of mantle contaminations in their *** metallogenic differences between the eastern(W–Mo)and western(Cu–Fe–Pb–Zn)parts of Ningzhen also indicate different proportions of crustal materials in their magma source.

关键词： Ancient lower continental crust Paleo-pacific plate High Mg#adaktic rocks Early cretaceous Ningzhen Crustal thickening

Highly Luminescent Positively Charged Quantum Dots Interacting with Proteins and Cells

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Chinese Journal of Chemistry 2022年第22期40卷 2685-2693页

作者： Haixia Wang Karin Nienhaus Li Shang Gerd Ulrich Nienhaus Institute of Applied Physics Karlsruhe Institute of Technology(KIT)76131 KarlsruheGermany Institute of Nanotechnology Karlsruhe Institute of Technology(KIT)76344 Eggenstein-LeopoldshafenGermany InstituteofBiologicaland Chemical Systems Karlsruhe Institute of Technology(KIT)76344 Eggenstein-LeopoldshafenGermany Department of Physics University of llinois at Urbana-ChampaignUrbanaIL61801USA present address:Laboratory of Biomaterials and Translational Medicine Center for NanomedicineThe Third Affiliated HospitalSun Yat-sen UniversityGuangzhou510630China present address:School of Materials Science and Engineering Northwestern PolytechnicalUniversityXi'an 710072China

We have studied interactions between positively charged MUTAB-stabilized quantum dots(QDs)and model proteins,serum and live cells using fluorescence correlation spectroscopy(FCS),dynamic light scattering(DLS),time-resolved photoluminescence(PL)and live-cell fluorescence *** human serum albumin(HSA)as a model protein,we measured the growth of a protein adsorption layer(“protein corona”)via time-resolved *** formation was characterized by an apparent equilibrium dissociation coefficient,KD≈10μ*** adlayer growth was surprisingly slow(timescale ca.30 min),in stark contrast to many similar measurements with HSA and other proteins and different ***-resolved PL data revealed a characteristic quenching behavior depending on the QD surface coverage with *** together,we found that MUTAB-QDs initially bind HSA molecules weakly(KD≈700μM);however,the affinity is enhanced over time,presumably due to proton injection into the MUTAB layer by HSA triggering ligand *** process was also observed with human blood serum,showing equal kinetics for comparable HSA ***,imaging experiments with cultured human cells(HeLa)revealed that MUTAB-QDs bind to the cell membrane and perforate *** process is reduced upon pre-adsorption of proteins on the MUTAB-QD.

关键词： Quantum dots Nanoparticles Agglomeration Protein adsorption Quantitative fluorescence microscopy

EXECUTER2 modulates the EXECUTER1 signalosome through its singlet oxygen-dependent oxidation

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Molecular Plant 2022年第3期15卷 438-453页

作者： Vivek Dogra Rahul Mohan Singh Mengping Li Mingyue Li Somesh Singh Chanhong Kim Shanghai Center for Plant Stress Biology CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai 200032China University of the Chinese Academy of Sciences Beijing 100049China present address:Biotechnology Division CSIR-Institute of Himalayan Bioresource TechnologyPalampur 176061India

Oxidative post-translational modifications of specific chloroplast proteins contribute to the initiation of retrograde *** Arabidopsis thaliana EXECUTER1(EX1)protein,a chloroplast-localized singlet oxygen(^(1)O_(2))sensor,undergoes tryptophan(Trp)643 oxidation by^(1)O_(2),a chloroplast-derived and light-dependent reactive oxygen *** indole side chain of Trp is vulnerable to^(1)O_(2),leading to the generation of oxidized Trp variants and priming EX1 for degradation by a membrane-bound FtsH *** perception of^(1)O_(2)via Trp643 oxidation and subsequent EX1 proteolysis facilitate chloroplast-to-nucleus retrograde *** this study,we discovered that the EX1-like protein EX2 also undergoes^(1)O_(2)-dependent Trp530 oxidation and FtsH-dependent turnover,which attenuates^(1)O_(2)signaling by decelerating EX1-Trp643 oxidation and subsequent EX1 *** with this finding,the loss of EX2 function reinforces EX1-dependent retrograde signaling by accelerating EX1-Trp643 oxidation and subsequent EX1 proteolysis,whereas overexpression of EX2 produces molecular phenotypes opposite to those observed in the loss-of-function mutants of ***,phylogenetic analysis suggests that EX2 may have emerged evolutionarily to attenuate the sensitivity of EX1 toward^(1)O_(2).Collectively,these results suggest that EX2 functions as a negative regulator of the EX1 signalosome through its own^(1)O_(2)-dependent oxidation,providing a new mechanistic insight into the regulation of EX1-mediated^(1)O_(2)signaling.

关键词： EXECUTER1 EXECUTER2 singlet oxygen retrograde signaling Trp oxidation FtsH protease

Inhibition of Cdk5 increases osteoblast differentiation and bone mass and improves fracture healing

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Bone Research 2022年第3期10卷 469-481页

作者： Mubashir Ahmad Benjamin Thilo Krüger Torsten Kroll Sabine Vettorazzi Ann-Kristin Dorn Florian Mengele Sooyeon Lee Sayantan Nandi Dilay Yilmaz Miriam Stolz Naveen Kumar Tangudu David Carro Vázquez Johanna Pachmayr Ion Cristian Cirstea Maja Vujic Spasic Aspasia Ploubidou Anita Ignatius Jan Tuckermann Institute of Comparative Molecular Endocrinology(CME) Ulm UniversityHelmholtzstrasse 8/189081 UlmGermany Institute of Orthopedic Research and Biomechanics Ulm UniversityHelmholtzstrasse 1489081 UlmGermany Leibniz Institute on Aging–Fritz Lipmann Institute(FLI) Beutenbergstrasse 11D-07745 JenaGermany Praxisklinik für Orthopädie Unfall-und Neurochirurgie Prof.Bischoff/Dr.Spies/Dr.Mengele89231 Neu-UlmGermany Paracelsus Medizinische Privatuniverstät Institute of PharmacyStrubergasse 215020 SalzburgAustria Department of Endocrinology Ludwig Maximilians University MunichMunich 80336Germany present address:Institute of Orthopedic Research and Biomechanics Ulm UniversityHelmholtzstrasse 1489081 UlmGermany present address:UPMC Hillman Cancer Center Department of Pharmacology and Chemical BiologyUniversity of Pittsburgh5115 Center Avenue15232 PittsburghPAUSA present address:TAmiRNA GmbH Leberstrasse 201110 ViennaAustria

Identification of regulators of osteoblastogenesis that can be pharmacologically targeted is a major goal in combating osteoporosis,a common disease of the elderly population. Here, unbiased kinome RNAi screening in primary murine osteoblasts identified cyclin-dependent kinase 5(Cdk5) as a suppressor of osteoblast differentiation in both murine and human preosteoblastic cells. Cdk5 knockdown by si RNA, genetic deletion using the Cre-lox P system, or inhibition with the small molecule roscovitine enhanced osteoblastogenesis in vitro. Roscovitine treatment significantly enhanced bone mass by increasing osteoblastogenesis and improved fracture healing in mice. Mechanistically, downregulation of Cdk5 expression increased Erk phosphorylation, resulting in enhanced osteoblast-specific gene expression. Notably, simultaneous Cdk5 and Erk depletion abrogated the osteoblastogenesis conferred by Cdk5 depletion alone, suggesting that Cdk5 regulates osteoblast differentiation through MAPK pathway modulation. We conclude that Cdk5 is a potential therapeutic target to treat osteoporosis and improve fracture healing.

关键词： Cdk5 healing expression

Cellular and Molecular Requirements for Polar PIN Targeting and Transcytosis in Plants

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Molecular Plant 2008年第6期1卷 1056-1066页

作者： Jurgen Kleine-Vehn tukasz tangowski Justyna Wisniewska Pankaj Dhonukshe Philip B Brewer Jiri Friml Department of Plant Systems Biology VIB and Department of Molecular Genetics Ghent University 9052 Gent Belgium Zentrum fur Molekularbiologie der Pflanzen (ZMBP) Universitat Tubingen 72076 Tubingen Germany present address: Institute of General and Molecular Biology Nicolas Copernicus University 87-100 Torun Poland present address: Department of Biology Utrecht University 3508 TB Utrecht The Netherlands present address: Centre for Integrative Legume Research University of Queensland Brisbane Australia

The polar, sub-cellular localization of PIN auxin efflux carriers determines the direction of intercellular auxin flow, thus defining the spatial aspect of auxin signalling. Dynamic, transcytosis-like relocalizations of PIN proteins occur in response to external and internal signals, integrating these signals into changes in auxin distribution. Here, we examine the cellular and molecular mechanisms of polar PIN delivery and transcytosis. The mechanisms of the ARF-GEF-dependent polar targeting and transcytosis are well conserved and show little variations among diverse Arabidopsis ecotypes consistent with their fundamental importance in regulating plant development. At the cellular level, we refine previous findings on the role of the actin cytoskeleton in apical and basal PIN targeting, and identify a previously unknown role for microtubules, specifically in basal targeting. PIN protein delivery to different sides of the cell is mediated by ARFdependent trafficking with a previously unknown complex level of distinct ARF-GEF vesicle trafficking regulators. Our data suggest that alternative recruitment of PIN proteins by these distinct pathways can account for cell type- and cargo-specific aspects of polar targeting, as well as for polarity changes in response to different signals. The resulting dynamic PIN positioning to different sides of cells defines a three-dimensional pattern of auxin fluxes within plant tissues.

关键词： cytoskeleton polarity protein targeting.