Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 953
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Nature ; 612(7940): 540-545, 2022 12.
Article in English | MEDLINE | ID: mdl-36323336

ABSTRACT

The BA.2 sublineage of the SARS-CoV-2 Omicron variant has become dominant in most countries around the world; however, the prevalence of BA.4 and BA.5 is increasing rapidly in several regions. BA.2 is less pathogenic in animal models than previously circulating variants of concern1-4. Compared with BA.2, however, BA.4 and BA.5 possess additional substitutions in the spike protein, which play a key role in viral entry, raising concerns that the replication capacity and pathogenicity of BA.4 and BA.5 are higher than those of BA.2. Here we have evaluated the replicative ability and pathogenicity of BA.4 and BA.5 isolates in wild-type Syrian hamsters, human ACE2 (hACE2) transgenic hamsters and hACE2 transgenic mice. We have observed no obvious differences among BA.2, BA.4 and BA.5 isolates in growth ability or pathogenicity in rodent models, and less pathogenicity compared to a previously circulating Delta (B.1.617.2 lineage) isolate. In addition, in vivo competition experiments revealed that BA.5 outcompeted BA.2 in hamsters, whereas BA.4 and BA.2 exhibited similar fitness. These findings suggest that BA.4 and BA.5 clinical isolates have similar pathogenicity to BA.2 in rodents and that BA.5 possesses viral fitness superior to that of BA.2.


Subject(s)
COVID-19 , Genetic Fitness , Rodentia , SARS-CoV-2 , Animals , Cricetinae , Humans , Mice , COVID-19/virology , Mesocricetus/virology , Mice, Transgenic , Rodentia/virology , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Animals, Genetically Modified , Genetic Fitness/genetics , Genetic Fitness/physiology , Virulence
2.
Nature ; 607(7917): 119-127, 2022 07.
Article in English | MEDLINE | ID: mdl-35576972

ABSTRACT

The recent emergence of SARS-CoV-2 Omicron (B.1.1.529 lineage) variants possessing numerous mutations has raised concerns of decreased effectiveness of current vaccines, therapeutic monoclonal antibodies and antiviral drugs for COVID-19 against these variants1,2. The original Omicron lineage, BA.1, prevailed in many countries, but more recently, BA.2 has become dominant in at least 68 countries3. Here we evaluated the replicative ability and pathogenicity of authentic infectious BA.2 isolates in immunocompetent and human ACE2-expressing mice and hamsters. In contrast to recent data with chimeric, recombinant SARS-CoV-2 strains expressing the spike proteins of BA.1 and BA.2 on an ancestral WK-521 backbone4, we observed similar infectivity and pathogenicity in mice and hamsters for BA.2 and BA.1, and less pathogenicity compared with early SARS-CoV-2 strains. We also observed a marked and significant reduction in the neutralizing activity of plasma from individuals who had recovered from COVID-19 and vaccine recipients against BA.2 compared to ancestral and Delta variant strains. In addition, we found that some therapeutic monoclonal antibodies (REGN10987 plus REGN10933, COV2-2196 plus COV2-2130, and S309) and antiviral drugs (molnupiravir, nirmatrelvir and S-217622) can restrict viral infection in the respiratory organs of BA.2-infected hamsters. These findings suggest that the replication and pathogenicity of BA.2 is similar to that of BA.1 in rodents and that several therapeutic monoclonal antibodies and antiviral compounds are effective against Omicron BA.2 variants.


Subject(s)
Antiviral Agents , COVID-19 Drug Treatment , SARS-CoV-2 , Animals , Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing/pharmacology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/pharmacology , Antibodies, Viral/therapeutic use , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/genetics , COVID-19/immunology , COVID-19/virology , Cricetinae , Cytidine/analogs & derivatives , Drug Combinations , Hydroxylamines , Indazoles , Lactams , Leucine , Mice , Nitriles , Proline , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Triazines , Triazoles
3.
Nature ; 603(7902): 687-692, 2022 03.
Article in English | MEDLINE | ID: mdl-35062015

ABSTRACT

The recent emergence of B.1.1.529, the Omicron variant1,2, has raised concerns of escape from protection by vaccines and therapeutic antibodies. A key test for potential countermeasures against B.1.1.529 is their activity in preclinical rodent models of respiratory tract disease. Here, using the collaborative network of the SARS-CoV-2 Assessment of Viral Evolution (SAVE) programme of the National Institute of Allergy and Infectious Diseases (NIAID), we evaluated the ability of several B.1.1.529 isolates to cause infection and disease in immunocompetent and human ACE2 (hACE2)-expressing mice and hamsters. Despite modelling data indicating that B.1.1.529 spike can bind more avidly to mouse ACE2 (refs. 3,4), we observed less infection by B.1.1.529 in 129, C57BL/6, BALB/c and K18-hACE2 transgenic mice than by previous SARS-CoV-2 variants, with limited weight loss and lower viral burden in the upper and lower respiratory tracts. In wild-type and hACE2 transgenic hamsters, lung infection, clinical disease and pathology with B.1.1.529 were also milder than with historical isolates or other SARS-CoV-2 variants of concern. Overall, experiments from the SAVE/NIAID network with several B.1.1.529 isolates demonstrate attenuated lung disease in rodents, which parallels preliminary human clinical data.


Subject(s)
COVID-19/pathology , COVID-19/virology , Disease Models, Animal , SARS-CoV-2/pathogenicity , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Cricetinae , Female , Humans , Lung/pathology , Lung/virology , Male , Mesocricetus , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , Viral Load
4.
Plant Cell ; 2024 May 09.
Article in English | MEDLINE | ID: mdl-38723588

ABSTRACT

Compared with transcription and translation, protein degradation machineries can act faster and be targeted to different subcellular compartments, enabling immediate regulation of signaling events. It is therefore not surprising that proteolysis has been used extensively to control homeostasis of key regulators in different biological processes and pathways. Over the past decades, numerous studies have shown that proteolysis, where proteins are broken down to peptides or amino acids through ubiquitin-mediated degradation systems and proteases, is a key regulatory mechanism to control plant immunity output. Here, we briefly summarize the roles various proteases play during defense activation, focusing on recent findings. We also update the latest progress of ubiquitin-mediated degradation systems in modulating immunity by targeting plant membrane-localized pattern recognition receptors (PRRs), intracellular nucleotide-binding domain leucine-rich repeat receptors (NLRs), and downstream signaling components. Additionally, we highlight recent studies showcasing the importance of proteolysis in maintaining broad-spectrum resistance without obvious yield reduction, opening new directions for engineering elite crops that are resistant to a wide range of pathogens with high yield.

5.
Proc Natl Acad Sci U S A ; 119(29): e2203701119, 2022 Jul 19.
Article in English | MEDLINE | ID: mdl-35858304

ABSTRACT

Conjugated polymers usually require strategies to expand the range of wavelengths absorbed and increase solubility. Developing effective strategies to enhance both properties remains challenging. Herein, we report syntheses of conjugated polymers based on a family of metalla-aromatic building blocks via a polymerization method involving consecutive carbyne shuttling processes. The involvement of metal d orbitals in aromatic systems efficiently reduces band gaps and enriches the electron transition pathways of the chromogenic repeat unit. These enable metalla-aromatic conjugated polymers to exhibit broad and strong ultraviolet-visible (UV-Vis) absorption bands. Bulky ligands on the metal suppress π-π stacking of polymer chains and thus increase solubility. These conjugated polymers show robust stability toward light, heat, water, and air. Kinetic studies using NMR experiments and UV-Vis spectroscopy, coupled with the isolation of well-defined model oligomers, revealed the polymerization mechanism.

6.
Nano Lett ; 24(21): 6269-6277, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38743874

ABSTRACT

Accurately decoding the three-dimensional atomic structure of surface active sites is essential yet challenging for a rational catalyst design. Here, we used comprehensive techniques combining the pair distribution function and reverse Monte Carlo simulation to reveal the surficial distribution of Pd active sites and adjacent coordination environment in palladium-copper nanoalloys. After the fine-tuning of the atomic arrangement, excellent catalytic performance with 98% ethylene selectivity at complete acetylene conversion was obtained in the Pd34Cu66 nanocatalysts, outperforming most of the reported advanced catalysts. The quantitative deciphering shows a large number of active sites with a Pd-Pd coordination number of 3 distributed on the surface of Pd34Cu66 nanoalloys, which play a decisive role in highly efficient semihydrogenation. This finding not only opens the way for guiding the precise design of bimetal nanocatalysts from atomic-level insight but also provides a method to resolve the spatial structure of active sites.

7.
Circulation ; 147(19): 1444-1460, 2023 05 09.
Article in English | MEDLINE | ID: mdl-36987924

ABSTRACT

BACKGROUND: Myocardial ischemia-reperfusion (I/R) injury causes cardiac dysfunction to myocardial cell loss and fibrosis. Prevention of cell death is important to protect cardiac function after I/R injury. The process of reperfusion can lead to multiple types of cardiomyocyte death, including necrosis, apoptosis, autophagy, and ferroptosis. However, the time point at which the various modes of cell death occur after reperfusion injury and the mechanisms underlying ferroptosis regulation in cardiomyocytes are still unclear. METHODS: Using a left anterior descending coronary artery ligation mouse model, we sought to investigate the time point at which the various modes of cell death occur after reperfusion injury. To discover the key molecules involved in cardiomyocyte ferroptosis, we performed a metabolomics study. Loss/gain-of-function approaches were used to understand the role of 15-lipoxygenase (Alox15) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1α) in myocardial I/R injury. RESULTS: We found that apoptosis and necrosis occurred in the early phase of I/R injury, and that ferroptosis was the predominant form of cell death during the prolonged reperfusion. Metabolomic profiling of eicosanoids revealed that Alox15 metabolites accumulated in ferroptotic cardiomyocytes. We demonstrated that Alox15 expression was specifically increased in the injured area of the left ventricle below the suture and colocalized with cardiomyocytes. Furthermore, myocardial-specific knockout of Alox15 in mice alleviated I/R injury and restored cardiac function. 15-Hydroperoxyeicosatetraenoic acid (15-HpETE), an intermediate metabolite derived from arachidonic acid by Alox15, was identified as a trigger for cardiomyocyte ferroptosis. We explored the mechanism underlying its effects and found that 15-HpETE promoted the binding of Pgc1α to the ubiquitin ligase ring finger protein 34, leading to its ubiquitin-dependent degradation. Consequently, attenuated mitochondrial biogenesis and abnormal mitochondrial morphology were observed. ML351, a specific inhibitor of Alox15, increased the protein level of Pgc1α, inhibited cardiomyocyte ferroptosis, protected the injured myocardium, and caused cardiac function recovery. CONCLUSIONS: Together, our results established that Alox15/15-HpETE-mediated cardiomyocyte ferroptosis plays an important role in prolonged I/R injury.


Subject(s)
Arachidonate 15-Lipoxygenase , Ferroptosis , Myocardial Reperfusion Injury , Animals , Mice , Apoptosis , Arachidonate 12-Lipoxygenase/metabolism , Arachidonate 12-Lipoxygenase/pharmacology , Arachidonate 15-Lipoxygenase/genetics , Arachidonate 15-Lipoxygenase/metabolism , Arachidonate 15-Lipoxygenase/pharmacology , Myocardial Reperfusion Injury/genetics , Myocardial Reperfusion Injury/metabolism , Myocytes, Cardiac/metabolism , Necrosis/metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Ubiquitins/metabolism , Ubiquitins/pharmacology
8.
Opt Express ; 32(2): 1764-1775, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38297721

ABSTRACT

Optoelectronic integrated circuits (OEICs) have enhanced integration and communication capabilities in various applications. With the continued increase in complexity and scale, the need for an accurate and efficient simulation environment compatible with photonics and electronics becomes paramount. This paper introduces a method using the Verilog-A hardware language in the electronic design automation (EDA) platform to create equivalent circuit and compact models for photonic devices, considering their dispersion, polarization, multimode, and bidirectional transmission characteristics. These models can be co-simulated alongside electrical components in the electronic simulator, covering both the time and frequency domains simultaneously. Model parameters can be modified at any stage of the design process. Using the full link of an optoelectronic transceiver as an example, analyses from our Verilog-A model system show a mean absolute percentage error of 1.55% in the time-domain and 0.0318% in the frequency-domain when compared to the commercial co-simulation system (e.g., Virtuoso-INTERCONNECT). This underscores the accuracy and efficiency of our approach in OEICs design. By adopting this method, designers are enabled to conduct both electrical-specific and photonic-specific circuit analyses, as well as perform optoelectronic co-simulation within a unified platform seamlessly.

9.
Chemistry ; 30(10): e202303401, 2024 Feb 16.
Article in English | MEDLINE | ID: mdl-38057690

ABSTRACT

The synthesis of highly efficient visible-light-responsive photocatalysts is fundamental to solving the problems of low efficiency and poor selectivity in photocatalytic organic synthesis reactions. We synthesized a crystalline polyoxometalate @metal-organic framework material {Zn4 (H2 O)8 [Ir(ppy)2 (dcbpy)]4 [SiW12 O40 ]} ⋅ 4H2 O (Ir-SiW) by self-assembly of Ir metalloligands with POMs. The introduction of Ir metalloligands extends the light absorbing range to visible light, improving the efficient utilization of solar energy. The transfer of photogenerated electrons from Ir metalloligands to SiW12 was observed under visible light irradiation, which boosted the carrier separation efficiency. The synergistic effect of the two components increased the photocatalytic thioether oxidation activity, and the product methyl phenyl sulfoxide for 2.5 h under visible light irradiation (λ >400 nm) reached 99.5 %, which was higher than those of other POM-based photocatalysts. Meanwhile, the yield of methyl phenyl sulfoxide was still higher than 97 % after three cycles, demonstrating the high stability and reusability of Ir-SiW.

10.
Chemistry ; 30(14): e202302921, 2024 Mar 07.
Article in English | MEDLINE | ID: mdl-38183325

ABSTRACT

An unclassical structure of {Ru(C6 H6 )}-based polyoxometalate, Cs6 H4 [Te2 Mo12 O46 {Ru(C6 H6 )}] ⋅ 16.5H2 O (1), has been successfully constructed from {Te2 Mo12 O46 }-type heteropolymolybdate and {Ru(C6 H6 )} group, which structure type was discovered for the first time. Compound 1 not only possesses strong light-harvesting ability, but also exhibits high carrier separation efficiency and lower charge transfer resistance. Under visible light irradiation, compound 1 displayed excellent catalytic activity and circularity in the conversion of benzyl alcohol to benzaldehyde (yield=94 %; turnover number=500; turnover frequency=20.8 h-1 ). Finally, the electron paramagnetic resonance measurement and energy level matching analysis provide theoretical basis for the derivation of the reaction mechanism.

11.
Theor Appl Genet ; 137(4): 78, 2024 Mar 11.
Article in English | MEDLINE | ID: mdl-38466414

ABSTRACT

KEY MESSAGE: A genetic linkage map representing proso millet genome was constructed with SSR markers, and a major QTL corresponding to plant height was mapped on chromosome 14 of this map. Proso millet (Panicum miliaceum L.) has the lowest water requirements of all cultivated cereal crops. However, the lack of a genetic map and the paucity of genomic resources for this species have limited the utility of proso millet for detailed genetic studies and hampered genetic improvement programs. In this study, 97,317 simple sequence repeat (SSR) markers were developed based on the genome sequence of the proso millet landrace Longmi 4. Using some of these markers in conjunction with previously identified SSRs, an SSR-based linkage map for proso millet was successfully constructed using a large mapping population (316 F2 offspring). In total, 186 SSR markers were assigned to 18 linkage groups corresponding to the haploid chromosomes. The constructed map had a total length of 3033.42 centimorgan (cM) covering 78.17% of the assembled reference genome. The length of the 18 linkage groups ranged from 88.89 cM (Chr. 15) to 274.82 cM (Chr. 16), with an average size of 168.17 cM. To our knowledge, this is the first genetic linkage map for proso millet based on SSR markers. Plant height is one of the most important traits in crop improvement. A major QTL was repeatedly detected in different environments, explaining 8.70-24.50% of the plant height variations. A candidate gene affecting auxin biosynthesis and transport, and ROS homeostasis regulation was predicted. Thus, the linkage map and QTL analysis provided herein will promote the development of gene mining and molecular breeding in proso millet.


Subject(s)
Panicum , Panicum/genetics , Chromosome Mapping , Phenotype , Microsatellite Repeats , Genetic Linkage , Genome, Plant
12.
Circ Res ; 130(6): 851-867, 2022 03 18.
Article in English | MEDLINE | ID: mdl-35176871

ABSTRACT

BACKGROUND: Metabolic syndrome is related to cardiovascular diseases, which is attributed in part, to arterial stiffness; however, the mechanisms remain unclear. The present study aimed to investigate the molecular mechanisms of metabolic syndrome-induced arterial stiffness and to identify new therapeutic targets. METHODS: Arterial stiffness was induced by high-fat/high-sucrose diet in mice, which was quantified by Doppler ultrasound. Four-dimensional label-free quantitative proteomic analysis, affinity purification and mass spectrometry, and immunoprecipitation and GST (glutathione S-transferase) pull-down experiments were performed to explore the mechanism of YAP (Yes-associated protein)-mediated TGF (transforming growth factor) ß pathway activation. RESULTS: YAP protein was upregulated in the aortic tunica media of mice fed a high-fat/high-sucrose diet for 2 weeks and precedes arterial stiffness. Smooth muscle cell-specific YAP knockdown attenuated high-fat/high-sucrose diet-induced arterial stiffness and activation of TGFß-Smad2/3 signaling pathway in arteries. By contrast, Myh11CreERT2-YapTg mice exhibited exacerbated high-fat/high-sucrose diet-induced arterial stiffness and enhanced TGFß-activated Smad2/3 phosphorylation in arteries. PPM1B (protein phosphatase, Mg2+/Mn2+-dependent 1B) was identified as a YAP-bound phosphatase that translocates into the nucleus to dephosphorylate Smads (mothers against decapentaplegic homologs) in response to TGFß. This process was inhibited by YAP through removal of the K63-linked ubiquitin chain of PPM1B at K326. CONCLUSIONS: This study provides a new mechanism by which smooth muscle cell YAP regulates the TGFß pathway and a potential therapeutic target in metabolic syndrome-associated arterial stiffness.


Subject(s)
Metabolic Syndrome , Vascular Stiffness , Animals , Diet, High-Fat/adverse effects , Mice , Proteomics , Sucrose , Transforming Growth Factor beta/metabolism , Transforming Growth Factor beta1/metabolism , Vascular Stiffness/physiology , YAP-Signaling Proteins
13.
Crit Rev Food Sci Nutr ; : 1-16, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38976377

ABSTRACT

In the current context, diabetes presents itself as a widespread and complex global health issue. This study explores the significant influence of food microstructure and food matrix components interaction (protein, lipid, polyphenols, etc.) on the starch digestibility and the glycaemic response of post-prandial glycemia, focusing on the potential effectiveness of incorporating bioactive components from whole grain cereals into dietary strategies for the management and potential prevention of diabetes. This study aims to integrate the regulation of postprandial glycaemic homeostasis, including the complexities of starch digestion, the significant potential of bioactive whole grain components and the impact of food processing, to develop a comprehensive framework that combines these elements into a strategic approach to diabetes nutrition. The convergence of these nutritional strategies is analyzed in the context of various prevalent dietary patterns, with the objective of creating an accessible approach to mitigate and prevent diabetes. The objective remains to coalesce these nutritional paradigms into a coherent strategy that not only addresses the current public health crisis but also threads a preventative approach to mitigate future prevalence and impact.

14.
Faraday Discuss ; 2024 May 29.
Article in English | MEDLINE | ID: mdl-38807494

ABSTRACT

Sulfur atoms serve as key players in diverse chemical processes, from astrochemistry at very low temperature to combustion at high temperature. Building upon our prior findings, showing cyclization to thiophenes following the reaction of ground-state sulfur atoms with dienes, we here extend this investigation to include many additional reaction products, guided by detailed theoretical predictions. The outcomes highlight the complex formation of products during intersystem crossing (ISC) to the singlet surfaces. Here, we employed crossed-beam velocity map imaging and high-level ab initio methods to explore the reaction of S(3P) with 1,3-butadiene and isoprene under single-collision conditions and in low-temperature flows. For the butadiene reaction, our experimental results show the formation of thiophene via H2 loss, a 2H-thiophenyl radical through H loss, and thioketene through ethene loss at a slightly higher collision energy compared to previous observations. Complementary Chirped-Pulse Fourier-Transform mmWave spectroscopy (CP-FTmmW) measurements in a uniform flow confirmed the formation of thioketene in the reaction at 20 K. For the isoprene reaction, we observed analogous products along with the 2H-thiophenyl radical arising from methyl loss and C3H4S (loss of ethene or H2 + acetylene). CP-FTmmW detected the formation of thioformaldehyde via loss of 1,3-butadiene, again in the 20 K flow. Coupled-cluster calculations on the pathways found by the automated kinetic workflow code KinBot support these findings and indicate ISC to the singlet surface, leading to the generation of various long-lived intermediates, including 5-membered heterocycles.

15.
J Org Chem ; 89(12): 8447-8457, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38832810

ABSTRACT

An efficient and practical strategy for the construction of pyrrolo[3,4-c]isoquinolines via Rh(III)-catalyzed cascade C-H activation and subsequential annulation process from easily available O-methyl aryloximes and maleimides has been disclosed. This facile protocol does not require any inert atmosphere protection with good efficiency in a low loading of catalyst and exhibits good functional group tolerance and broad substrate scope. Notably, the as-prepared products show potential photophysical properties.

16.
J Org Chem ; 89(12): 8420-8434, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38836769

ABSTRACT

An elegant and highly concise strategy for the construction of coumarin-functionalized pyrrolo[2,1-a]isoquinolines from available propargylamines and isoquinolinium N-ylides has been disclosed. In this reaction, isoquinolinium N-ylides acted as a C2 synthon to form a coumarin ring as well as a 1,3-dipole to construct a pyrrole ring in a single pot. This cascade process involves 1,4-conjugate addition/lactonization/1,3-dipolar cycloaddition to construct four chemical bonds (one C-O bond and three C-C bonds) and two new heterocyclic skeletons. Additionally, most of these compounds showed good fluorescence properties and exhibited high molar extinction coefficient and large Stokes shifts.

17.
Physiol Plant ; 176(2): e14277, 2024.
Article in English | MEDLINE | ID: mdl-38566271

ABSTRACT

In order to maintain the dynamic physiological balance, plants are compelled to adjust their energy metabolism and signal transduction to cope with the abiotic stresses caused by complex and changeable environments. The diterpenoid natural compound and secondary metabolites, sclareol, derived from Salvia sclarea, has gained significant attention owing to its economic value as a spice material and diverse physiological activities. Here, we focused on the roles and regulatory mechanisms of the sclareol diterpene synthase gene SsdTPS in the resistance of S. sclarea to abiotic stresses. Our results suggested that abiotic stresses could induce the response and upregulation of SsdTPS expression and isoprenoid pathway in S. sclarea. Ectopic expression of SsdTPS conferred drought tolerance in transgenic Arabidopsis, compared with wild-type. Overexpression of SsdTPS enhanced the transcription of ABA signal transduction synthetic regulators and induced the positive feedback upregulating key regulatory genes in the MEP pathway, thereby promoting the increase of ABA content and improving drought tolerance in transgenic plants. In addition, SsdTPS-overexpressed transgenic Arabidopsis improved the responses of stomatal regulatory genes and ROS scavenging enzyme activities and gene expression to drought stress. This promoted the stomatal closure and ROS reduction, thus enhancing water retention capacity and reducing oxidative stress damage. These findings unveil the potentially positive role of SsdTPS in orchestrating multiple regulatory mechanisms and maintaining homeostasis for improved abiotic stress resistance in S. sclarea, providing a novel insight into strategies for promoting drought resistance and cultivating highly tolerant plants.


Subject(s)
Arabidopsis , Diterpenes , Arabidopsis/metabolism , Reactive Oxygen Species/metabolism , Droughts , Feedback , Plants, Genetically Modified/genetics , Stress, Physiological/genetics , Terpenes , Gene Expression Regulation, Plant , Plant Proteins/metabolism , Abscisic Acid/pharmacology
18.
Physiol Plant ; 176(1): e14197, 2024.
Article in English | MEDLINE | ID: mdl-38344855

ABSTRACT

Increased acid phosphatase (APase) activity is a prominent feature of tomato (Solanum lycopersicum) responses to inorganic phosphate (Pi) restriction. SlPHL1, a phosphate starvation response (PHR) transcription factor, has been identified as a positive regulator of low Pi (LP)-induced APase activity in tomato. However, the molecular mechanism underlying this regulation remains to be elucidated. Here, SlPHL1 was found to positively regulate the LP-induced expression of five potential purple acid phosphatase (PAP) genes, namely SlPAP7, SlPAP10b, SlPAP12, SlPAP15, and SlPAP17b. Furthermore, we provide evidence that SlPHL1 can stimulate transcription of these five genes by binding directly to the PHR1 binding sequence (P1BS) located on their promoters. The P1BS mutation notably weakened SlPHL1 binding to the promoters of SlPAP7, SlPAP12, and SlPAP17b but almost completely abolished SlPHL1 binding to the promoters of SlPAP10b and SlPAP15. As a result, the transcriptional activation of SlPHL1 on SlPAP10b and SlPAP15 was substantially diminished. In addition, not only did transient overexpression of either SlPAP10b or SlPAP15 in tobacco leaves increase APase activity, but overexpression of SlPAP15 in Arabidopsis and tomato also increased APase activity and promoted plant growth. Subsequently, two SPX proteins, SlSPX1 and SlSPX4, were shown to physically interact with SlPHL1. Moreover, SlSPX1 inhibited the transcriptional activation of SlPHL1 on SlPAP10b and SlPAP15 and negatively regulated the activity of APase. Taken together, these results demonstrate that SlPHL1-mediated LP signaling promotes APase activity by activating the transcription of SlPAP10b and SlPAP15, which may provide valuable insights into the mechanisms of tomato response to Pi-limited stress.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Solanum lycopersicum , Phosphates , Solanum lycopersicum/genetics , Transcription Factors/metabolism , Arabidopsis/metabolism , Acid Phosphatase/genetics , Acid Phosphatase/metabolism , Gene Expression Regulation, Plant , Arabidopsis Proteins/metabolism
19.
Inorg Chem ; 63(16): 7325-7333, 2024 Apr 22.
Article in English | MEDLINE | ID: mdl-38602808

ABSTRACT

The synthesis of visible light-responsive and efficient photocatalysts toward green Baeyer-Villiger oxidation organic synthesis is of extraordinary significance. In this work, we have synthesized two examples of visible light responsive crystalline polyoxometalate@metal-organic framework materials Ru-NiMo and Ru-CoMo by introducing Ru metalloligands and {CdM3O12} bimetallic units (M = Ni or Co). This is the first report of metalloligand-modified polyoxometalate@metal-organic framework materials with bimetallic nodes, and the materials form a three-dimensional framework directly through coordination bonds between {CdM3O12} bimetallic units and metalloligands. In particular, Ru-NiMo can achieve efficient photocatalytic conversion of cyclohexanone to ε-caprolactone in yields as high as 95.5% under visible light excitation in the range of λ > 400 nm, achieving a turnover number and turnover frequency of 955 and 440 h-1, respectively, which are the best known photocatalysts for Baeyer-Villiger oxidation, while apparent quantum yield measured at 485 nm is 4.4%. Moreover, Ru-NiMo exhibited excellent structural stability and recyclability, producing a 90.8% yield after five cycles of recycling.

20.
Inorg Chem ; 63(14): 6260-6267, 2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38517738

ABSTRACT

In this paper, we have successfully synthesized a structurally novel heteropolytungstate via coordination of four {Ru(C6H6)} and trivacant {TeW9O33} clusters, formulated as Cs4Na2H2[Te2W20O72(H2O){(C6H6)Ru}4]·12H2O (1). Compound 1 inherited the strong absorption of [Ru(C6H6)Cl2]2 in the visible region and {TeW9O33} in the UV region, providing a good basis for photocatalysis. As expected, compound 1 showed good photocatalytic activity in the visible-light-driven reduction of nitrobenzene using N2H4·H2O as a reductant with a yield of 99.8%, a high turnover number (TON = 330), and a high turnover frequency (TOF = 24 h-1). The cyclic experiment of nitrobenzene reduction indicated that compound 1 was an effective and stable heterogeneous catalyst. Finally, the nitrobenzene reduction pathway was affirmed using condensation with azobenzene as a reaction intermediate based on control experiments.

SELECTION OF CITATIONS
SEARCH DETAIL