Strigolactones modulate cotton fiber elongation and secondary cell wall thickening

Cotton is one of the most important economic crops in the world,and it is a major source of fiber in the textile industry.Strigolactones(SLs)are a class of carotenoid-derived plant hormones involved in many processes of plant growth and development,although the functions of SL in fiber development remain largely unknown.Here,we found that the endogenous SLs were significantly higher in fibers at 20 days post-anthesis(DPA).Exogenous SLs significantly increased fiber length and cell wall thickness.Furthermore,we cloned three key SL biosynthetic genes,namely GhD27,GhMAX3,and GhMAX4,which were highly expressed in fibers,and subcellular localization analyses revealed that GhD27,GhMAX3,and GhMAX4 were localized in the chloroplast.The exogenous expression of GhD27,GhMAX3,and GhMAX4 complemented the physiological phenotypes of d27,max3,and max4 mutations in Arabidopsis,respectively.Knockdown of GhD27,GhMAX3,and GhMAX4 in cotton resulted in increased numbers of axillary buds and leaves,reduced fiber length,and significantly reduced fiber thickness.These findings revealed that SLs participate in plant growth,fiber elongation,and secondary cell wall formation in cotton.These results provide new and effective genetic resources for improving cotton fiber yield and plant architecture.

Chemokine platelet factor 4 accelerates peripheral nerve regeneration by regulating Schwann cell activation and axon elongation

Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.

Investigation of hydroxyl-terminated polybutadiene propellant breaking characteristics and mechanism impacted by submerged cavitation water jet

A submerged cavitation water jet(SCWJ)is an effective method to recycle solid propellant from obsolete solid engines by the breaking method.Solid propellant's breaking modes and mechanical process under SCWJ impact are unclear.This study aims to understand those impact breaking mechanisms.The hydroxyl-terminated polybutadiene(HTPB)propellant was chosen as the research material,and a self-designed test system was used to conduct impact tests at four different working pressures.The high-speed camera characterized crack propagation,and the DIC method calculated strain change during the impact process.Besides,micro and macro fracture morphologies were characterized by scanning electron microscope(SEM)and computed tomography(CT)scanning.The results reveal that the compressive strain concentration region locates right below the nozzle,and the shear strain region distributes symmetrically with the jet axis,which increases to 4% at first 16th ms,the compressive strain rises to 2% and 6% in the axial and transverse direction,respectively.The two tensile cracks formed first at the compression strain concentrate region,and there generate many shear cracks around the tensile cracks,and those shear cracks that develop and aggregate cause the cracks to become wider and cut through the tensile cracks,forming the tensile-shear cracks and the impact parts eventually fail.The HTPB propellant forms a breaking hole shaped conical after impact 10 s.The mass loss increases by 17 times at maximum,with the working pressure increasing by three times.Meanwhile,the damage value of the breaking hole remaining on the surface increases by 7.8 times while 2.9 times in the depth of the breaking hole.The breaking efficiency is closely affected by working pressures.The failure modes of HTPB impacted by SCWJ are classified as tensile crack-dominated and tensile-shear crack-dominated damage mechanisms.

Vital contribution of brassinosteroids to hypoxia-stimulated coleoptile elongation in submerged rice

The rapid elongation of rice(Oryza sativa)coleoptile is pivotal for the plant plumule to evade hypoxia stress induced by submergence,a condition often arising from overirrigation,ponding,rainstorms,or flooding.While brassinosteroids(BRs)are recognized for their diverse roles in plant growth and development,their influence on coleoptile elongation under hypoxic conditions remains largely unexplored.In this study,we demonstrate the significant requirement of BRs for coleoptile elongation in deep water.During coleoptile development,Glycogen Synthase Kinase3-Like Kinase2(GSK2),the central inhibitor of BR signaling in rice,undergoes substantial suppression in deep water but induction in air.In contrast,the dephosphorylated form of BRASSINAZOLE RESISTANT1(OsBZR1),representing the active form of the key BR signaling transcription factor,is induced in water but suppressed in air.Remarkably,the knockout of GSK3-like kinase genes significantly enhances coleoptile elongation in deep water,strongly indicating a vital contribution of BR response to hypoxia-stimulated coleoptile elongation.Transcriptome analysis uncovers both BR-associated and BR-independent hypoxia responses,implicating substance metabolism,redox reactions,abiotic stress responses,and crosstalk with other hormones in the regulation of BR-induced hypoxia responses.In summary,our findings suggest that rice plumules rapidly elongate coleoptiles through the activation of BR response in deep water,enabling them to escape from submergence-induced hypoxia stress.

The bHLH transcription factor CsPIF4 positively regulates high temperature-induced hypocotyl elongation in cucumber

High temperature-induced hypocotyl elongation is a typical thermomorphogenesis trait that may significantly affect early seedling growth and subsequent crop yield.The ambient temperature and endogenous auxin are two critical factors that regulate hypocotyl growth.However,the mechanism of temperature and auxin integration in horticultural plants remains poorly understood.In this study,the roles of the basic helix-loop-helix transcription factor CsPIF4 in regulating auxin biosynthesis genes and the auxin content in the hypocotyl of cucumber(Cucumis sativus L.)seedlings under high temperature were investigated.qRT-PCR and in situ hybridization analysis revealed that expression of CsPIF4 was enhanced in the epidermis and vascular bundles in the hypocotyl of cucumber seedlings in response to high temperature.qRT-PCR and HPLC analysis showed that CsPIF4 positively regulated transcription of the auxin biosynthesis gene CsYUC8 and the auxin content in the hypocotyl under high temperature(35℃).The CRISPR/Cas9-mediated knockout of CsPIF4 resulted in a shorter hypocotyl compared with that of the wild type,together with decreased expression of CsYUC8 and lower auxin content in response to high temperature.Furthermore,biochemical assays showed that CsPIF4 could bind directly to the G-box motif of the CsYUC8 promoter and thereby activate CsYUC8 expression.These findings provide insight into the molecular mechanism of high temperature-mediated hypocotyl elongation in cucumber.

Chain Elongation Using Native Soil Inocula:Exceptional n-Caproate Biosynthesis Performance and Microbial Mechanisms

This study demonstrates the feasibility and effectiveness of utilizing native soils as a resource for inocula to produce n-caproate through the chain elongation(CE)platform,offering new insights into anaerobic soil processes.The results reveal that all five of the tested soil types exhibit CE activity when supplied with high concentrations of ethanol and acetate,highlighting the suitability of soil as an ideal source for n-caproate production.Compared with anaerobic sludge and pit mud,the native soil CE system exhibited higher selectivity(60.53%),specificity(82.32%),carbon distribution(60.00%),electron transfer efficiency(165.00%),and conductivity(0.59 ms∙cm^(-1)).Kinetic analysis further confirmed the superiority of soil in terms of a shorter lag time and higher yield.A microbial community analysis indicated a positive correlation between the relative abundances of Pseudomonas,Azotobacter,and Clostridium and n-caproate production.Moreover,metagenomics analysis revealed a higher abundance of functional genes in key microbial species,providing direct insights into the pathways involved in n-caproate formation,including in situ CO_(2)utilization,ethanol oxidation,fatty acid biosynthesis(FAB),and reverse beta-oxidation(RBO).The numerous functions in FAB and RBO are primarily associated with Pseudomonas,Clostridium,Rhodococcus,Stenotrophomonas,and Geobacter,suggesting that these genera may play roles that are involved or associated with the CE process.Overall,this innovative inoculation strategy offers an efficient microbial source for n-caproate production,underscoring the importance of considering CE activity in anaerobic soil microbial ecology and holding potential for significant economic and environmental benefits through soil consortia exploration.

Determination of the flooding zone during a dam break in a channel with a bend in the presence of several obstacles by the VOF method

This paper aims to investigate a dam break in a channel with a bend in the presence of several obstacles.To accurately determine the flood zones,it is necessary to take into account many factors such as terrain,reservoir volume.Numerical modeling was used to determine the flood zone.Numerical modeling based on the Navier-Stokes equations with a turbulent k-epsilon RNG model,the Volume of Fluid(VOF)method and the PISO algorithm were used to analyze the flow in a bend channel at an angle of 10 with the obstacles.To verify the numerical model,a test on dam break in the 450 channel was conducted.The simulation results were compared with experimental data and with the numerical data of existing data.Having been convinced of the correctness of the mathematical model,the authors carried out a numerical simulation of the main problem in three versions:without barriers,with one obstacle,with two obstacles.According to the obtained numerical results,it can be noted that irregular landforms held the flow,a decrease in water level and a slower time for water emergence could be seen.Thus,the water flow without an obstacle,with one obstacle and with two obstacles showed 4.2 s,4.4 s and 4.6 s of the time of water appearance,respectively.This time shift can give a certain advantage when conducting various events to evacuate people.

Cavitation cloud impingement and scattering motion of jet in rock breaking process

The cavitation cloud impingement of the jet in the rock breaking process was experimentally investigated to reveal the jet erosion mechanism in drilling of petroleum exploitation. Serial erosion tests and flow visualization were performed, where the cavitation cloud motion in the erosion crater was obtained with the designed transparent specimen. Various erosion patterns were identified in the whole erosion process based on the eroded specimen topography. The shallow eroded crater with a shrinking erosion area is generated by the combination of impinging and scattering cavitation clouds. The increase of l_(d) promotes the development of cavitation cloud σ_(c) but reduces the impingement frequency f_(d), suggesting that the jet aggressive ability is enhanced when the balance between σ_(c) and f_(d) is reached. The cavitation cloud motion in the erosion crater was investigated with the transparent specimen. The erosion in the crater at shorter exposure periods T_(e) is generated by the combination of impingement and restricted scattering of cavitation clouds. With the continuous development of the erosion damage, the jet's aggressive ability is diminished due to the erosion expansion on sandstone, where the cavitation clouds impinge on the target and then collapse and vanish without restricted scattering.

Across two phylogeographic breaks: Quaternary evolutionary history of a mountain aspen (Populus rotundifolia) in the Hengduan Mountains

Biogeographical barriers to gene flow are central to plant phylogeography.In East Asia,plant distribution is greatly influenced by two phylogeographic breaks,the Mekong-Salween Divide and Tanaka-Kaiyong Line,however,few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both.Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia,a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China.Demographic and migration hypotheses were tested using coalescent-based approaches.Limited historical gene flow was observed between the western and eastern groups of P.rotundifolia,but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line,manifesting in clear admixture and high genetic diversity in the central group.Wind-borne pollen and seeds may have facilitated the dispersal of P.rotundifolia following prevalent northwest winds in the spring.We also found that the Hengduan Mountains,where multiple genetic barriers were detected,acted on the whole as a barrier between the western and eastern groups of P.rotundifolia.Ecological niche modeling suggested that P.rotundifolia has undergone range expansion since the last glacial maximum,and demographic reconstruction indicated an earlier population expansion around 600 Ka.The phylogeographic pattern of P.rotundifolia reflects the interplay of biological traits,wind patterns,barriers,niche differentiation,and Quaternary climate history.This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas.

Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon-neutral hydrogen mass production yet challenging.Circumventing scaling relations is an effective strategy to break through the bottleneck of natural seawater splitting.Herein,by DFT calculation,we demonstrated that the interface boundaries between Ni_(2)P and MoO_(2) play an essential role in the selfrelaxation of the Ni-O interfacial bond,effectively modulating a coordination number of intermediates to control independently their adsorption-free energy,thus circumventing the adsorption-energy scaling relation.Following this conceptual model,a well-defined 3D F-doped Ni_(2)P-MoO_(2) heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater electrolysis.As a result,the F-Ni_(2)P-MoO_(2) exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid,alkaline,and alkaline sea water-based electrolytes.By in-situ analysis,we found that a thin amorphous layer of NiOOH,which is evolved from the Ni_(2)P during anodic reaction,is real catalytic active sites for the OER and UOR processes.Remarkable,such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and600 mA cm^(-2)and demonstrates superior durability by operating continuously for 100 h at 100 mA cm^(-2),beyond commercial Pt/C||RuO_(2) and most previous reports.

Team China’s Groundbreaking Success at Paris Olympics

China’s Olympic delegation at the Paris 2024,with 404 athletes competing in 232 events across 30 sports,clinched 40 gold,27 silver,and 24 bronze medals,marking their best performance at an Olympics held abroad.The success of these athletes across various disciplines demonstrates the country’s efforts to expand its athletic prowess while also marks a new chapter for Chinese sportsmanship on the international stage.

Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply

A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.

Increased Elongation at Breaking Point with Improved Mechanical Characteristics in PLA

The main goal of this research was to increase the strength of Polylactic acid (PLA), an entirely biodegradable thermoplastic polyester, and an increase in elongation at the breaking point compared to neat PLA. To this end, S1, S2, and S3 were melt blended with various percentages of Zeolite, Glycerol, White vinegar, green camphor, Eucalyptus, and Carom seed oils. Here, the addition of glycerol, eucalyptus, and carom seed oils demonstrated an average improvement in impact and tensile strength of 13.44% and 14.55% respectively. Zeolite and glycerol work together as binding agents to improve stress transfer in the matrix, which increases tensile and flexural modulus as well as toughness elongation (>10%). The addition of the aforementioned materials led to an increase in the glass transition temperature and melting temperature, according to further DSC investigation. The thermal stability increased gradually, according to TGA data.

Impacts of monsoon break events in the western North Pacific on the cross-equatorial flows over the Maritime Continent

本文利用ERA5逐日再分析资料,探讨了1979-2020年间西北太平洋季风中断事件对海洋性大陆越赤道气流的影响.合成结果表明,西北太平洋季风中断事件会造成高,低空越赤道气流减弱,即高层南风异常,低层北风异常,与此相关的环流异常表现为西北太平洋高层气旋,低层反气旋的斜压结构。特别的是,西北太平洋季风中断对高空越赤道气流的影响更为显著,92%的季风中断事件都导致高空越赤道气流减弱,而只有70%的事件造成低空越赤道气流减弱,这是由于低空越赤道气流同时还受到赤道中东太平洋海温异常的调控.

Numerical Simulation of Dam-Break Flows Using Radial Basis Functions: Application to Urban Flood Inundation

Dam-break flows pose significant threats to urban areas due to their potential for causing rapid and extensive flooding. Traditional numerical methods for simulating these events struggle with complex urban landscapes. This paper presents an alternative approach using Radial Basis Functions to simulate dam-break flows and their impact on urban flood inundation. The proposed method adapts a new strategy based on Particle Swarm Optimization for variable shape parameter selection on meshfree formulation to enhance the numerical stability and convergence of the simulation. The method’s accuracy and efficiency are demonstrated through numerical experiments, including well-known partial and circular dam-break problems and an idealized city with a single building, highlighting its potential as a valuable tool for urban flood risk management.

Prokaryotic Expression of Rubber Elongation Factor Gene and Preparation of Its Polyclonal Antibody

[Objective] The aim of this study was to prepare the recombination protein of rubber elongation factor and its polyclonal antibodies.[Method] The encoding gene of rubber elongation factor(REF)was amplified by RT-PCR,and cloned into the prokaryotic expression vector pDEST17 to transform into Escherichia coil BI2I-AI.The recombinant protein induced by L-Arabinose was purified by the affinity chromatography.As the immunogen,the recombination protein was used to immunize mice for preparing polyclonal antibodies,while ELISA and Western blot hybridization were used to detect the titers and specificity.[Result] The purified recombination protein of REF with high expression was used to immunize house mice for preparing polyclonal antibodies with high titer and specificity.The western blot hybridization showed that the antibody could recognize the natural REF from latex.[Conclusion] The recombination protein of REF was successfully obtained and the mouse anti REF antibody with high titer and specificity was prepared,which lays a basis for further studies on biological functions of rubber elongation factor and other membrane proteins in rubber particles.

Inducible Expression of Translation Elongation Factor 1A Gene in Rice Seedlings in Response to Environmental Stresses

Differences of gene expression between salinity_stressed and control rice ( Oryza sativa L. ssp. indica ) cultivar “Zhaiyeqing 8' were compared using differential display PCR (DD_PCR) technique. Sequence analysis of one salt_inducible cDNA clone revealed that this clone represented a new member of rice translation elongation factor 1A (eEF1A) gene family and was tentatively named REF1A. Northern blot hybridization using REF1A fragment as a probe was performed to investigate the expression of rice translation elongation factor 1A gene in response to various environmental factors. It was observed that expression of the eEF1A gene in rice shoots was dramatically induced by salinity stress or exogenous application of abscisic acid (ABA). The induction of this gene by ABA stress occurred more quickly than that by salinity stress. In addition, expression of rice translation elongation factor 1A gene was also induced by drought (15% PEG6000), cold (4 ℃) or heat_shock (37 ℃) stresses. The results suggested that the induction of translation elongation factor 1A gene expression by environmental stresses might reflect the general adaptive response of rice plants to the adverse circumstances.

Tolerance of Salix matsudana to Heavy Metals Determined by Root Elongation Method

[Objective]The research aimed to discuss the tolerance of Salix matsudana to single or compound heavy metals and provide theoretical basis for renovating polluted soil by heavy metals with woody plants.[Method]Using root elongation method,the effects of heavy metal Cu^2＋,Pb^2＋,Zn^2＋ and their mixed solution on the adventitious roots growth of S.matsudana cuttings were studied.[Result]The adventitious roots growth of S.matsudana cuttings was obviously affected by different concentrations of heavy metals solution.Adventitious roots of S.matsudana cuttings could not grow while the concentration of Cu^2＋ was higher than 15 mg/L,the mixture solution concentration was higher than 20 mg/L and Zn^2＋ concentration was higher than 30 mg/L.When the solution concentration reached 40 mg/L,adventitious roots of S.matsudana cuttings could grow only in Pb^2＋ treatment group.With the increasing of the solution concentration,the number of adventitious roots of S.matsudana cuttings gradually decreased.In 5 mg/L Zn^2＋ treatment group,the number of adventitious roots of S.matsudana cuttings was the most,the longest root length and average root length were the longest and the rooting rate was the highest.[Conclusion]The tolerance of S.matsudana to Pb^2＋ was strongest and its tolerance to Cu^2＋ was the weakest.The tolerance order of S.matsudana to three kinds of heavy metals and their mixed solution was as following：Pb^2＋〉Zn^2＋〉Cu^2＋＋Pb^2＋＋Zn^2＋〉Cu^2＋.

WAVE TRANSFORMATION AND BREAKING OVER A RECTANGULAR STEP

An idealized numerical wave flume has been established by finite element method on the bases of Navier Stokes equations through prescribing the appropriate boundary conditions for the open boundary,incident boundary,free surface and solid boundary in this paper.The characteristics of waves propagating over a step have been investigated by this numerical model.The breaker wave height is determined depending on the kinetic criterion.The numerical model is verified by laboratory experiments,and the empirical formula for the damping of wave height due to breaking is also given by experiments.

羊驼transcription elongation factor B(S III)(Tceb2)cDNA的获取与序列分析

【研究目的】分离和鉴定羊驼transcription elongation factorB(S III)(Tceb2)基因,分析其序列特征,为今后研究其生物学功能奠定理论基础。【方法】用Southern Blotting法从羊驼皮肤cDNA文库中筛选Tceb2基因,通过BLAST等生物学相关软件对其进行结果分析。【结果】有6个阳性克隆,测序结果得知,序列片段大小大约为472bp,具有完整的开放阅读框,可编码119AA,分子量为13.2KDa。序列特征、结构和同源性分析表明:该序列预测为全长cDNA序列,该基因序列及其编码的氨基酸序列与大鼠和小鼠的troponinc2同源性可达100%。【结论】该基因是获得的羊驼全长Tceb2(GenBank DQ646397)(命名为AlpTceb2)。