Suppressing a mitochondrial calcium uniporter activates the calcium signaling pathway and promotes cell elongation in cotton

Mitochondrial calcium uniporter(MCU)is a conserved calcium ion(Ca^(2+))transporter in the mitochondrial inner membrane of eukaryotic cells.How MCU proteins regulate Ca^(2+)flow and modulate plant cell development remain largely unclear.Here,we identified the gene GhMCU4 encoding a MCU protein that negatively regulates plant development and fiber elongation in cotton(Gossypium hirsutum).GhMCU4expressed constitutively in various tissues with the higher transcripts in elongating fiber cells.Knockdown of GhMCU4 in cotton significantly elevated the plant height and root length.The calcium signaling pathway was significantly activated and calcium sensor genes,including Ca^(2+)dependent modulator of interactor of constitutively active ROP(GhCMI1),calmodulin like protein(GhCML46),calciumdependent protein kinases(GhCPKs),calcineurin B-like protein(GhCBLs),and CBL-interacting protein kinases(GhCIPKs),were dramatically upregulated in GhMCU4-silenced plants.Metabolic processes were preferentially enriched,and genes related to regulation of transcription were upregulated in GhMCU4-silenced plants.The contents of Ca^(2+)and H_(2)O_(2)were significantly increased in roots and leaves of GhMCU4-silenced plants.Fiber length and Ca^(2+)and H_(2)O_(2)contents in fibers were significantly increased in GhMCU4-silenced plants.This study indicated that GhMCU4 plays a negative role in regulating cell elongation in cotton,thus expanding understanding in the role of MCU proteins in plant growth and development.

Ice-Induced Vibrational Response of Single-Pile Offshore Wind-Turbine Foundations

Important challenges must be addressed to make wind turbines sustainable renewable energy sources.A typical problem concerns the design of the foundation.If the pile diameter is larger than that of the jacket platform,traditional mechanical models cannot be used.In this study,relying on the seabed soil data of an offshore wind farm,the m-method and the equivalent embedded method are used to address the single-pile wind turbine foundation problem for different pile diameters.An approach to determine the equivalent pile length is also proposed accordingly.The results provide evidence for the effectiveness and reliability of the model based on the equivalent embedded method.

Radiation-hardened property of single-walled carbon nanotube film-based field-effect transistors under low-energy proton irradiation

Strong C-C bonds,nanoscale cross-section and low atomic number make single-walled carbon nanotubes(SWCNTs)a potential candidate material for integrated circuits(ICs)applied in outer space.However,very little work combines the simulation calculations with the electrical measurements of SWCNT field-effect transistors(FETs),which limits further understanding on the mechanisms of radiation effects.Here,SWCNT film-based FETs were fabricated to explore the total ionizing dose(TID)and displacement damage effect on the electrical performance under low-energy proton irradiation with different fluences up to 1×1015 p/cm2.Large negative shift of the threshold voltage and obvious decrease of the on-state current verified the TID effect caused in the oxide layer.The stability of the subthreshold swing and the off-state current reveals that the displacement damage caused in the CNT layer is not serious,which proves that the CNT film is radiation-hardened.Specially,according to the simulation,we found the displacement damage caused by protons is different in the source/drain contact area and channel area,leading to varying degrees of change for the contact resistance and sheet resistance.Having analyzed the simulation results and electrical measurements,we explained the low-energy proton irradiation mechanism of the CNT FETs,which is essential for the construction of radiation-hardened CNT film-based ICs for aircrafts.

Mining elite loci and candidate genes for root morphology-related traits at the seedling stage by genome-wide association studies in upland cotton(Gossypium hirsutum L.)

Root system architecture plays an essential role in water and nutrient acquisition in plants,and it is significantly involved in plant adaptations to various environmental stresses.In this study,a panel of 242 cotton accessions was collected to investigate six root morphological traits at the seedling stage,including main root length(MRL),root fresh weight(RFW),total root length(TRL),root surface area(RSA),root volume(RV),and root average diameter(AvgD).The correlation analysis of the six root morphological traits revealed strong positive correlations of TRL with RSA,as well as RV with RSA and AvgD,whereas a significant negative correlation was found between TRL and AvgD.Subsequently,a genome-wide association study(GWAS)was performed using the root phenotypic and genotypic data reported previously for the 242 accessions using 56,010 single nucleotide polymorphisms(SNPs)from the CottonSNP80K array.A total of 41 quantitative trait loci(QTLs)were identified,including nine for MRL,six for RFW,nine for TRL,12 for RSA,12 for RV and two for AvgD.Among them,eight QTLs were repeatedly detected in two or more traits.Integrating these results with a transcriptome analysis,we identified 17 candidate genes with high transcript values of transcripts per million(TPM)≥30 in the roots.Furthermore,we functionally verified the candidate gene GH_D05G2106,which encodes a WPP domain protein 2in root development.A virus-induced gene silencing(VIGS)assay showed that knocking down GH_D05G2106significantly inhibited root development in cotton,indicating its positive role in root system architecture formation.Collectively,these results provide a theoretical basis and candidate genes for future studies on cotton root developmental biology and root-related cotton breeding.

二十一世纪的理论生态学

生态学是关于自然模式的科学,主要研究自然界中各种类型的生物在分布、多度和动态等方面所表现出来的规律或模式(Mac Arthur,1972)。从大量的观察描述中识别模式,如遗传/物种多样性的纬度梯度等,毫无疑问是非常重要的。但更重要的是,我们需要理解这些自然模式是怎样产生的,或者说是哪些生态学过程导致了人们所观察到的模式?这是摆在理论生态学工作者面前的首要任务(张大勇, 2000)。

Rhodium(Ⅰ)-Catalyzed [4+2] Cycloaddition Reactions of 2-Alkylenecyclobutanols with Alkynes and (E)+-2-Nitroethenylbenzene through C(sp2)-C(sp3) Bond Cleavage

Summary of main observation and conclusion An intermolecular [4+2] cycloaddition was realized through C-C bond cleavage in the presence of Rh(Ⅰ) catalyst.The selective ring opening of 2-alkylenecyciobutanols enables the generation of active alkenylrhodium species,which underwent smooth cross addition over alkynes and (E)-2-nitroethenylbenzene,leading to highly substituted all-carbon six-membered rings in a single step and in a complete atom economy.

Control of vertical phase separation in high performance non-fullerene organic solar cell by introducing oscillating stratification preprocessing

Non-fullerene organic solar cell(NFOSC)has attracted tremendous attention due to their great potential for commercial applications.To improve its power conversion efficiency(PCE),generally,sequential solution deposition(SSD)methods have been employed to construct the graded vertical phase separation(VPS)of the bulk-heterojunction(BHJ)active layer for efficient exciton separation and charge transition.However,a variety of orthogonal solvents used in the SSD may lead to the unpredicted change in the BHJ morphology and introduce additional defects inside the BHJ bulk thus complicate the fabrication process.Here,a simple oscillating stratification preprocessing(OSP)is developed to facilitate the formation of graded VPS among the BHJ layer.As a result,a significant improvement is obtained in PCE from 10.96%to 12.03%,which is the highest value reported among PBDB-T:ITIC based NFOSC.

New Ligands for Copper-Catalyzed C-N Coupling Reactions at Gentle Temperature

Pyridin-2-ol-N-oxide was designed as an efficient ligand for the coupling reaction of aryl iodides,aryl bromides and aryl chlorides,respectively,with primary amines,cyclic secondary amines or N-containing heterocycles at room or moderate temperature.The catalytic system showed great functional groups tolerance and excellent selective reactivity.

Neutral theory in community ecology

One of the central goals of community ecology is to understand the forces that maintain species diversity within communities.The traditional niche-assembly theory asserts that species live together in a community only when they differ from one another in resource uses.But this theory has some difficulties in explaining the diversity often observed in specie-rich communities such as tropical forests.As an alternative to the niche theory,Hubbell and other ecologists introduced a neutral model.Hubbell argues that the number of species in a community is controlled by species extinction and immigration or speciation of new species.Assuming that all individuals of all species in a trophically similar com-munity are ecologically equivalent,Hubbell’s neutral theory predicts two important statistical distributions.One is the asymptotic log-series distribution for the metacommunities under point mutation speciation,and the other is the zero-sum multinomial distribution for both local communities under dispersal limitation and metacommunities under random fission speciation.Unlike the niche-assembly theory,the neutral theory takes similarity in species and individuals as a starting point for investigating species diversity.Based on the fundamental processes of birth,death,dispersal and spe-ciation,the neutral theory provided the first mechanistic explanation of species abundance distribution commonly observed in natural communities.Since the publication of the neutral theory,there has been much discussion about it,pro and con.In this paper,we summarize recent progress in the assumption,prediction and speciation mode of the neutral theory,including progress in the theory itself,tests about the assumption of the theory,prediction and speciation mode at the metacommunity level.We also suggest that the most important task in the future is to bridge the niche-assembly theory and the neutral theory,and to add species differences to the neutral theory and more stochasticity to the niche theory.

A novel method for objectively, rapidly and accurately evaluating burn depth via near infrared spectroscopy

The accurate and objective evaluation of burn depth is a significant challenge in burn wound care.Herein,we used near infrared spectroscopy(NIRS)technology to measure the different depth of thermal burns in ex vivo porcine models.Based on the intensity of the spectral signals and the diffuse reflection theory,we extracted the optical parameters involved in functional(total hemoglobin andwater content)and structural(tissue scattered size and scattered particles)features that reflect the changes in burn depth.Next,we applied support vector regression to construct a model including the optical property parameters and the burn depth.Finally,we histologically verified the burn depth data collected via NIRS.The results showed that our inversion model could achieve an average relative error of about 7.63%,while the NIRS technology diagnostic accuracy was in the range of 50μm.For the first time,this novel technique provides physicians with real-time burn depth information objectively and accurately.