Artemisinin is a type of sesquiterpene lactone well known as an antimalarial drug, and is specifically produced in glandular trichomes of Artemisia annua. However, the regulatory network for the ...artemisinin biosynthetic pathway remains poorly understood. Exploration of trichome-specific transcription factors would facilitate the elucidation of regulatory mechanism of artemisinin biosynthesis.
The WRKY transcription factor GLANDULAR TRICHOME-SPECIFIC WRKY 1 (AaGSW1) was cloned and analysed in A. annua. AaGSW1 exhibited similar expression patterns to the trichome-specific genes of the artemisinin biosynthetic pathway and AP2/ERF transcription factor AaORA. A β-glucuronidase (GUS) staining assay further demonstrated that AaGSW1 is a glandular trichome-specific transcription factor.
AaGSW1 positively regulates CYP71AV1 and AaORA expression by directly binding to the W-box motifs in their promoters. Overexpression of AaGSW1 in A. annua significantly improves artemisinin and dihydroartemisinic acid contents; moreover, AaGSW1 can be directly regulated by AaMYC2 and AabZIP1, which are positive regulators of jasmonate (JA)-and abscisic acid (ABA)-mediated artemisinin biosynthetic pathways, respectively.
These results demonstrate that AaGSW1 is a glandular trichome-specific WRKY transcription factor and a positive regulator in the artemisinin biosynthetic pathway. Moreover, we propose that two trifurcate feed-forward pathways involving AaGSW1, CYP71AV1 and AaMYC2/AabZIP1 function in the JA/ABA response in A. annua.
The electron transport properties of atomically thin semiconductors such as MoS2 have attracted significant recent scrutiny and controversy. In this work, the scattering mechanisms responsible for ...limiting the mobility of single-layer semiconductors are evaluated. The roles of individual scattering rates are tracked as the two-dimensional electron gas density is varied over orders of magnitude at various temperatures. From a comparative study of the individual scattering mechanisms, we conclude that all current reported values of mobilities in atomically thin transition-metal dichalcogenide semiconductors are limited by ionized impurity scattering. When the charged impurity densities are reduced, remote optical phonon scattering will determine the ceiling of the highest mobilities attainable in these ultrathin materials at room temperature. The intrinsic mobilities will be accessible only in clean suspended layers, as is also the case for graphene. Based on the study, we identify the best choices for surrounding dielectrics that will help attain the highest mobilities.
Ferroelectric materials have demonstrated novel photovoltaic effect to scavenge solar energy. However, most of the ferroelectric materials with wide bandgaps (2.7–4 eV) suffer from low power ...conversion efficiency of less than 0.5% due to absorbing only 8–20% of solar spectrum. Instead of harvesting solar energy, these ferroelectric materials can be well suited for photodetector applications, especially for sensing near‐UV irradiations. Here, a ferroelectric BaTiO3 film‐based photodetector is demonstrated that can be operated without using any external power source and a fast sensing of 405 nm light illumination is enabled. As compared with photovoltaic effect, both the responsivity and the specific detectivity of the photodetector can be dramatically enhanced by larger than 260% due to the light‐induced photovoltaic–pyroelectric coupled effect. A self‐powered photodetector array system can be utilized to achieve spatially resolved light intensity detection by recording the output voltage signals as a mapping figure.
The photovoltaic–pyroelectric coupled effect is utilized to enhance the sensing performance of a self‐powered ITO/BaTiO3/Ag photodetector for realizing fast 405 nm light detection. A self‐powered photodetector array system can be utilized to achieve spatially resolved light‐intensity detection by recording the output voltage signals as a mapping figure.
Recent years have seen a considerable growth of research interests in developing novel technologies that permit designable manufacture and controllable manipulation of actuators. Among various ...fabrication and driving strategies, light has emerged as an enabler to reach this end, contributing to the development of actuators. Several accessible light‐mediated manufacturing technologies, such as ultraviolet (UV) lithography and direct laser writing (DLW), are summarized. A series of light‐driven strategies including optical trapping, photochemical actuation, and photothermal actuation for controllable manipulation of actuators is introduced. Current challenges and future perspectives of this field are discussed. To generalize, light holds great promise for the development of actuators.
Recent advances in light‐mediated manufacture and manipulation of actuators are highlighted. Several optical fabrication technologies, including UV lithography and direct laser writing, and various photo‐driven strategies, such as optical trapping, and photochemical and photothermal actuation are reviewed. Emerging trends and future perspectives of light‐enabled actuators are discussed.
This article uses a logarithmic growth model to analyze the correlation between the national economy and real estate. It reveals the Granger causality between the national economy and the real estate ...economy. The results show a long-term equilibrium relationship and a two-way Granger causality between real estate prices and economic growth. Excessive growth in real estate prices will create bubbles and will also drive economic growth backward.
Glandular trichomes are generally considered biofactories that produce valuable chemicals. Increasing glandular trichome density is a very suitable way to improve the productivity of these valuable ...metabolites, but little is known about the regulation of glandular trichome formation. Phytohormone jasmonate (JA) promotes glandular trichome initiation in various plants, but its mechanism is also unknown.
By searching transcription factors regulated by JA in Artemisia annua, we identified a novel homeodomain-leucine zipper transcription factor, HOMEODOMAIN PROTEIN 1 (AaHD1), which positively controls both glandular and nonglandular trichome initiations. Overexpression of AaHD1 in A. annua significantly increased glandular trichome density without harming plant growth. Consequently, the artemisinin content was improved.
AaHD1 interacts with A. annua jasmonate ZIM-domain 8 (AaJAZ8), which is a repressor of JA, thereby resulting in decreased transcriptional activity. AaHD1 knockdown lines show decreased sensitivity to JA on glandular trichome initiation, which indicates that AaHD1 plays an important role in JA-mediated glandular trichome initiation.
We identified a new transcription factor that promotes A. annua glandular trichome initiation and revealed a novel molecular mechanism by which a homeodomain protein transduces JA signal to promote glandular trichome initiation. Our results also suggested a connection between glandular and nonglandular trichome formations.
Molecular imaging is an essential tool for disease diagnostics and treatment. Direct imaging of low‐abundance nucleic acids in living cells remains challenging because of the relatively low ...sensitivity and insufficient signal‐to‐background ratio of conventional molecular imaging probes. Herein, we report a class of DNA‐templated gold nanoparticle (GNP)–quantum dot (QD) assembly‐based probes for catalytic imaging of cancer‐related microRNAs (miRNA) in living cells with signal amplification capacity. We show that a single miRNA molecule could catalyze the disassembly of multiple QDs with the GNP through a DNA‐programmed thermodynamically driven entropy gain process, yielding significantly amplified QD photoluminescence (PL) for miRNA imaging. By combining the robust PL of QDs with the catalytic amplification strategy, three orders of magnitude improvement in detection sensitivity is achieved in comparison with non‐catalytic imaging probe, which enables facile and accurate differentiation between cancer cells and normal cells by miRNA imaging in living cells.
Break it up! High‐sensitivity molecular imaging of microRNA in living cells is realized by DNA‐programmed catalytic disassembly of gold nanoparticles and quantum dots (QDs).
Ferroelectric materials can be utilized for fabricating photodetectors because of the photovoltaic effect. Enhancing the photovoltaic performance of ferroelectric materials is still a challenge. ...Here, a self-powered ultraviolet (UV) photodetector is designed based on the ferroelectric BiFeO3 (BFO) material, exhibiting a high current/voltage response to 365 nm light in heating/cooling states. The photovoltaic performance of the BFO-based device can be well modulated by applying different temperature variations, where the output current and voltage can be enhanced by 60 and 75% in heating and cooling states, respectively. The enhancement mechanism of the photocurrent is associated with both temperature effect and thermo-phototronic effect in the photovoltaic process. Moreover, a 4 × 4 matrix photodetector array has been designed for detecting the 365 nm light distribution in the cooling state by utilizing photovoltage signals. This study clarifies the role of the temperature effect and the thermo-phototronic effect in the photovoltaic process of the BFO material and provides a feasible route for pushing forward practical applications of self-powered UV photodetectors.
The strong interaction between graphene oxides (GO) and water molecules has trigged enormous research interest in developing GO‐based separation films, sensors, and actuators. However, sophisticated ...control over the ultrafast water transmission among the GO sheets and the consequent deformation of the entire GO film is still challenging. Inspired from the natural “quantum‐tunneling‐fluidics‐effect,” here quantum‐confined‐superfluidics‐enabled moisture actuation of GO paper by introducing periodic gratings unilaterally is reported. The folded GO nanosheets that act as quantum‐confined‐superfluidics channels can significantly promote water adsorption, enabling controllable and sensitive moisture actuation. Water‐adsorption‐induced expansion along and against the normal direction of a GO paper is investigated both theoretically and experimentally. Featuring state‐of‐the‐art of ultrafast response (1.24 cm−1 s−1), large deformation degree, and complex and predictable deformation, the smart GO papers are used for biomimetic mini‐robots including a creeping centipede and a smart leaf that can catch a living ladybug. The reported method is simple and universal for 2D materials, revealing great potential for developing graphene‐based smart robots.
Inspired by the natural “quantum‐tunneling‐fluidics‐effect,” moisture actuation of a solo graphene oxide (GO) paper enabled by quantum‐confined superfluidics is achieved by introducing unilateral nanofolding. Featuring a state‐of‐the‐art ultrafast response, large deformation degree, and complex and predictable deformation, the smart GO films are used for a creeping centipede and a smart leaf that can catch a living ladybug.
•Overview of novel QD synthetic methods.•Overview of novel type of QDs.•Overview of QDs for biosensing, bioimaging, and therapy applications.
During the past ten years significant advances have been ...achieved in quantum dot (QD) research field. The new synthetic methods and the discovery of new types of QDs have enabled a variety of new applications of QDs for bioimaging and biosensing. This review will focus on the most recent progress of QDs for biomedical applications. Ample examples will be given in this review on newly developed synthetic methods of QDs, non-toxic QDs, QDs for biomolecule detection, cell and animal imaging, and disease therapy.
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