Duplicated chalcone synthase(CHS)genes modulate flavonoid production in tea plants in response to light stress

In tea plants,the abundant flavonoid compounds are responsible for the health benefits for the human body and define the astringent flavor profile.While the downstream mechanisms of flavonoid biosynthesis have been extensively studied,the role of chalcone synthase(CHS)in this secondary metabolic process in tea plants remains less clear.In this study,we compared the evolutionary profile of the flavonoid metabolism pathway and discovered that gene duplication of CHS occurred in tea plants.We identified three CsCHS genes,along with a CsCHS-like gene,as potential candidates for further functional investigation.Unlike the CsCHS-like gene,the CsCHS genes effectively restored flavonoid production in Arabidopsis chs-mutants.Additionally,CsCHS transgenic tobacco plants exhibited higher flavonoid compound accumulation compared to their wild-type counterparts.Most notably,our examination of promoter and gene expression levels for the selected CHS genes revealed distinct responses to UV-B stress in tea plants.Our findings suggest that environmental factors such as UV-B exposure could have been the key drivers behind the gene duplication events in CHS.

高熔体强度聚丙烯发泡进展

本文介绍了聚丙烯发泡材料因其具有较高的刚性、优良的力学性能、良好热和化学稳定性及可回收性等,在多领域方面得以应用。而普通聚丙烯发泡温度窄,普遍提出以高熔体强度聚丙烯制备聚丙烯发泡材料。本文还介绍了制备高熔体强度聚丙烯四种方法及制备聚丙烯发泡材料的四种加工方法,并对聚丙烯发泡材料的应用前景进行探讨。

高熔体强度聚丙烯制备进展

本文分析了普通聚丙烯在加工过程中存在的问题,提出制备高熔体强度聚丙烯加以改善。介绍了高熔体强度聚丙烯的特点、四种制备高熔体强度聚丙烯方法及其应用。最后,本文对高熔体强度聚丙烯应用市场进行展望。

Identification and profile of phenolamides with anthracnose resistance potential in tea(Camellia sinensis)

Tea anthracnose is a prevalent disease in China that can lead to reduced tea production and lower quality,yet there is currently a lack of effective means for controlling this disease.In this study,we identified 46 phenolamides(including 27 isomers)in different tissues and organs of tea plants based on a developed workflow,and the secondary mass spectra of all these compounds have been documented.It was revealed that tea plants predominantly accumulate protonated aliphatic phenolamides,rather than aromatic phenolamides.The profile of phenolamides indicate that their buildup in tea plants is specific to certain tissues and acyl-acceptors,and this distribution is associated with the extent of phenolamide acyl-modification.Additionally,it was observed that N-Feruloylputrescine(Fer-Put,a type of phenolamides)was responsive to the stimulated accumulation of the tea anthracnose pathogen.The findings of anti-anthracnose experiments in vitro and on tea leaf demonstrated that Fer-Put was capable of significantly inhibiting the growth of anthracnose pathogen colony,effectively prevented tea leaf disease.Furthermore,it was observed that Fer-Put treatment can enhance the antioxidant enzyme activity of tea leaves.TEA002780.1 and TEA013165.1 gene may be responsible for the biosynthesis of Fer-Put in the disease resistance process in tea plants.Through these studies,the types and distribution of phenolamides in tea plants have been elucidated,and Fer-Put’s ability to resist anthracnose has been established,providing new insights into the resistance of tea anthracnose.

High-energy-density plasma in femtosecond-laser-irradiated nanowire-array targets for nuclear reactions

In this work,the high-energy-density plasmas(HEDP)evolved from joule-class-femtosecond-laser-irradiated nanowire-array(NWA)targets were numerically and experimentally studied.The results of particle-in-cell simulations indicate that ions accelerated in the sheath field around the surfaces of the nanowires are eventually confined in a plasma,contributing most to the high energy densities.The protons emitted from the front surfaces of the NWA targets provide rich information about the interactions that occur.We give the electron and ion energy densities for broad target parameter ranges.The ion energy densities from NWA targets were found to be an order of magnitude higher than those from planar targets,and the volume of the HEDP was several-fold greater.At optimal target parameters,8%of the laser energy can be converted to confined protons,and this results in ion energy densities at the GJ/cm^(3) level.In the experiments,the measured energy of the emitted protons reached 4 MeV,and the changes in energy with the NWA’s parameters were found to fit the simulation results well.Experimental measurements of neutrons from 2H(d,n)3He fusion with a yield of(24±18)×10^(6)/J from deuterated polyethylene NWA targets also confirmed these results.

The High Surface Ratio Micro-MoS₂Grain Composed of MoS₂Nanosheet Prepared with One-Step Hydrothermal Synthesis

Micro molybdenum disulfide was prepared with one-step hydrothermal method;the influence of reactant concentration and temperature on the surface ratio of micro-MoS2 grain was investigated. Raman spectroscopy (Raman), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to characterize the structure, composition and morphology of MoS2. The results show that micro-MoS2 grains were synthesized with one-step hydrothermal synthesis, and the morphology of micro-MoS2 grains is like flower and sphere. The SEM figures indicate that the surface ratio of micro-MoS2 grains is different and also show that the surface ratio of micro-MoS2 grains can be improved by regulating reactant concentration and temperature. This research showed a method to improve the surface ratio of micro-MoS2 grains.

Simulation and Optimization Characteristic of Novel MoS₂/c-Si HIT Solar Cell

Monolayer MoS2 has excellent optoelectronic properties, which is a potential material for solar cell. Though MoS2/c-Si heterojunction solar cell has been researched by many groups, little study of MoS2/c-Si solar cell physics is reported. In this paper, MoS2/c-Si heterojunction solar cells have been designed and optimized by AFORS-HET simulation program. The various factors affecting the performance of the cells were studied in details using TCO/n-type MoS2/i-layer/p-type c-Si/BSF/Al structure. Due to the important role of intrinsic layer in HIT solar cell, the effect of different intrinsic layers including a-Si:H, nc-Si:H, a-SiGe:H, on the performance of TCO/n-type MoS2/i-layer/p-type c-Si/Al cell, was studied in this paper. The results show that the TCO/n-type MoS2/i-layer/p-type c-Si/Al cell has the highest efficiency with a-SiGe:H as intrinsic layer, efficiency up to 21.85%. The back surface field effects on the properties of solar cells were studied with p + μc-Si and Al as BSF layers. And the effect of various factors such as thickness and band gap of intrinsic layer, thickness of MoS2, density of defect state and the energy band offset of MoS2/c-Si interface of TCO/n-type MoS2/i-layer nc-Si:H/p-type c-Si/Al cells, on the characteristics of solar cells, have been discussed for this kind of MoS2 heterojunction cells. The optimal solar cell with structure of TCO/n-type MoS2/i-type nc-Si:H/p-type c-Si/BSF/Al, has the best efficiency of 27.22%.

单向复合材料均质化弹性性能预测的集成学习模型:基于SHAP方法的可解释性分析

本研究提出了一种可解释的集成学习(EML)数据驱动方法,用于快速预测单向纤维增强复合材料的均质化弹性性能.我们选择了三种机器学习模型――随机森林(RF)、极端梯度提升机(XGBoost)和轻量梯度提升机(LGBM)来构建EML模型.基于实验并建立微观纤维分布的概率统计模型,结合有限元仿真,建立了反映纤维随机分布特征的代表性体元(RVE)模型,并创建相关数据集.通过准确性、效率、可解释性和泛化性等指标对EML模型的性能进行了全面评估,研究结果表明:(1)EML模型有效提升了基机器学习模型的预测精度(R2=0.962,MS E=5.41);(2)我们使用基于合作博弈理论的SHAP可解释性方法对预测结果进行了分析,其中,全局解释发现纤维的体积含量是影响复合材料均质化弹性性能的决定性变量,而局部解释阐明了输入特征对预测结果的关键影响机制;(3)EML模型在实验数据上表现出良好的泛化能力,计算结果与实验数据吻合度高,实现了复合材料均质化弹性性能的高效精准预测.

Removal of the C4-domain preserves the drought tolerance enhanced by CsMYB4a and eliminates the negative impact of this transcription factor on plant growth

The MYB4 transcription factor family regulates plant traits.However,their overexpression often results in undesirable side effects like growth reduction.We have reported a green tea(Camellia sinensis)MYB4 transcription factor(CsMYB4)that represses the phenylpropanoid and shikimate pathways and stunts plant growth and development.In the current study,we observed that in CsMYB4a transgenic tobacco(Nicotiana tabacum)plants,primary metabolism was altered,including sugar and amino acid metabolism,which demonstrated a pleiotropic regulation by CsMYB4a.The CsMYB4a transgenic tobacco plants had improved drought tolerance,which correlated to alterations in carbohydrate metabolism and an increase in proline content,as revealed by metabolic profiling and transcriptomic analysis.To mitigate the undesirable repressive side effects on plant traits,including dwarfism,shrunken leaves,and shorter roots of CsMYB4a transgenic plants,we deleted the C4 domain of CsMYB4a to obtain a CsMYB4a-DC4 variant and then overexpressed it in transgenic plants(CsMYB4a-DC4).These CsMYB4a-DC4 plants displayed a normal growth and had improved drought tolerance.Metabolite analysis demonstrated that the contents of carbohydrates and proline were increased in these transgenic plants.Our findings suggest that an approriate modification of TFs can generate novel crop traits,thus providing potential agricultural benefits and expanding its application to various crops.

Publisher Correction:Removal of the C4-domain preserves the drought tolerance enhanced by CsMYB4a and eliminates the negative impact of this transcription factor on plant growth

Publisher Correction:aBIOTECH https://doi.org/10.1007/s42994-024-00149-5 The original article has been updated to correct two errors introduced during production:In this article Xiu Li the same as Mingzhuo Li and Guoliang Ma should have been denoted as equally contributing authors.

Rapid eradication of antibiotic-resistant bacteria and biofilms by MXene and near-infrared light through photothermal ablation

With the development and rising of antimicrobial resistance,rapid and effective killings of bacteria are urgently needed,especially for antibiotic-resistant bacteria and bacterial biofilms that are usually hard to be treated with conventional antibiotics.Here,a rapid and broad-spectrum antibacterial strategy is demonstrated through photothermal ablation with MXene and light.Ti3C2 MXenes,when combined with 808 nm light,show significant antibacterial effects in just 20 min.The antibacterial strategy is effective to 15 bacterial species tested,including methicillin-resistant Staphylococcus aureus(MRSA)and vancomycin-resistant Enterococci(VRE).In addition,the rapid antibacterial strategy works for MRSA biofilms,by damaging the structures as well as killing bacteria in biofilms.Furthermore,the investigation of the antibacterial mechanisms shows that Ti3C2 with light kills bacteria mainly physically through inserting/contact and photothermal effect.This work broadens the potential applications of MXene and provides a way to eradicate bacteria and biofilms physically,without the likelihood of resistance development.

Neomycin biosynthesis is regulated positively by AfsA-g and NeoR in Streptomyces fradiae CGMCC 4.7387

Neomycins are a group of aminoglycoside antibiotics with both clinical and agricultural applications.To elucidate the regulatory mechanism of neomycin biosynthesis,we completed draft genome sequencing of a neomycin producer Streptomyces fradiae CGMCC 4.7387 from marine sediments,and the neomycin biosynthesis gene cluster was identified.Inactivation of the afsA-g gene encoding a γ-butyrolactone(GBL) synthase in S.fradiae CGMCC 4.7387 resulted in a significant decrease of neomycin production.Quantitative RT-PCR analysis revealed that the transcriptional level of neoR and the aphA-neoGH operon were reduced in the afsA-g::aac(3)Ⅳ mutant.Interestingly,a conserved binding site of AdpA,a key activator in the GBL regulatory cascade,was discovered upstream of neoR,a putative regulatory gene encoding a protein with an ATPase domain and a tetratricopeptide repeat domain.When neoR was inactivated,the neomycin production was reduced about 40%in comparison with the WT strain.Quantitative RT-PCR analysis revealed that the transcriptional levels of genes in the aphA-neoGH operon were reduced clearly in the neoR::aac(3)Ⅳ mutant.Finally,the titers of neomycin were improved considerably by overexpression of qfsA-gand neoR in S.fradiae CGMCC 4.7387.

Micro-size picosecond-duration fast neutron source driven by a laser-plasma wakefield electron accelerator

A pulsed fast neutron source is critical for applications of fast neutron resonance radiography and fast neutron absorption spectroscopy.However,due to the large transversal source size(of the order of mm)and long pulse duration(of the order of ns)of traditional pulsed fast neutron sources,it is difficult to realize high-contrast neutron imaging with high spatial resolution and a fine absorption spectrum.Here,we experimentally present a micro-size ultra-short pulsed neutron source by a table-top laser-plasma wakefield electron accelerator driving a photofission reaction in a thin metal converter.A fast neutron source with source size of approximately 500μm and duration of approximately 36 ps has been driven by a tens of MeV,collimated,micro-size electron beam via a hundred TW laser facility.This micro-size ultra-short pulsed neutron source has the potential to improve the energy resolution of a fast neutron absorption spectrum dozens of times to,for example,approximately 100 eV at 1.65 MeV,which could be of benefit for high-quality fast neutron imaging and deep understanding of the theoretical model of neutron physics.

Mesenteric lymph system constitutes the second route in gut-liver axis and transports metabolism-modulating gut microbial metabolites

The gut-liver axis denotes the intricate connection and interaction between gut microbiome and liver, in which compositional and functional shifts in gut microbiome affect host metabolism. Hepatic portal vein of the blood circulation system has been thought to be the major route for metabolite transportation in the gut-liver axis, but the existence and importance of other routes remain elusive. Here, we perform metabolome comparison in blood circulation and mesenteric lymph systems and identify significantly shifted metabolites in serum and mesentery. Using cellular assays, we find that the majority of decreased metabolites in lymph system under high-fat diet are effective in alleviating metabolic disorders, indicating a high potential of lymph system in regulating liver metabolism. Among those, a representative metabolite, L-carnitine, reduces diet-induced obesity in mice. Metabolic tracing analysis identifies that L-carnitine is independently transported by the mesenteric lymph system, serving as an example that lymph circulation comprises a second route in the gut-liver axis to modulate liver metabolism. Our study provides new insights into metabolite transportation via mesenteric lymph system in the gut-liver axis, offers an extended scope for the investigations in host-gut microbiota metabolic interactions and potentially new targets in the treatment of metabolic disorders.

Discovery of tanshinone derivatives with anti-MRSA activity via targeted bio-transformation

Two potent anti-MRSA tanshinone glycosides(1 and 2)were discovered by targeted microbial biotransformation,along with rapid identification via MS/MS networking.Serial reactions including dehydrogenation,demethylations,reduction,glycosylation and methylation have been observed after incubation of tanshinone IIA and fungus Mucor rouxianus AS 3.3447.In addition,tanshinosides B(2)showed potent activities against serial clinical isolates of oxacillin-resistant Staphylococcus aureus with MIC values of 0.78 mg/mL.This is the first study that shows a significant increase in the level and activities of tanshinone glycosides relative to the substrate tanshinone IIA.

基于成本视角的政府购买服务研究

政府购买公共服务的定价问题一直是公共服务市场化理论研究的难点,笔者在研究了北京、苏州、宁波政府购买服务定价实践后,发现成本管理视角可以为政府购买服务定价决策提供支持。本文结合道路养护维修政府购买服务的财务测算实际,介绍成本管理方法在政府购买服务管理实践中的应用,并结合思考提出了在政府购买服务定价中应用成本管理方法的适用条件、关键因素以及相关的意见建议,以期为成本管理方法在政府购买服务推广中发挥借鉴作用。