12 research outputs found

    Selective auxin agonists induce specific AUX/IAA protein degradation to modulate plant development.

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    Auxin phytohormones control most aspects of plant development through a complex and interconnected signaling network. In the presence of auxin, AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors are targeted for degradation by the SKP1-CULLIN1-F-BOX (SCF) ubiquitin-protein ligases containing TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB). CULLIN1-neddylation is required for SCFTIR1/AFB functionality, as exemplified by mutants deficient in the NEDD8-activating enzyme subunit AUXIN-RESISTANT 1 (AXR1). Here, we report a chemical biology screen that identifies small molecules requiring AXR1 to modulate plant development. We selected four molecules of interest, RubNeddin 1 to 4 (RN1 to -4), among which RN3 and RN4 trigger selective auxin responses at transcriptional, biochemical, and morphological levels. This selective activity is explained by their ability to consistently promote the interaction between TIR1 and a specific subset of AUX/IAA proteins, stimulating the degradation of particular AUX/IAA combinations. Finally, we performed a genetic screen using RN4, the RN with the greatest potential for dissecting auxin perception, which revealed that the chromatin remodeling ATPase BRAHMA is implicated in auxin-mediated apical hook development. These results demonstrate the power of selective auxin agonists to dissect auxin perception for plant developmental functions, as well as offering opportunities to discover new molecular players involved in auxin responses

    Regio- and Stereoselective Alkylation of Pyridine-N-oxides:Synthesis of Substituted Piperidines and Pyridines

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    Regio- and stereoselective addition of alkyl Grignard reagents to pyridine-N-oxides gave C2-alkylated N-hydroxy-1,2,5,6-tetrahydropyridines and trans-2,3-disubstituted N-hydroxy-1,2,5,6-tetrahydropyridines in good to excellent yields. These intermediates were aromatized or alternatively reduced in one-pot methodologies for efficient syntheses of alkylpyridines or piperidines, respectively. These reactions have a broad substrate scope and short reaction times

    Pd/C-mediated synthesis of (Z)-3-alkylidenephthalides of potential pharmacological interest

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    The coupling of o-bromobenzoic acid with terminal alkynes using 10% Pd/C–Et3N–CuI–PPh3 as a catalyst system leads to the synthesis of (Z)-3-alkylidenephthalides as the major product along with the traces of isocoumarin when the reaction was performed in 1,4-dioxane. The methodology afforded a range of compounds including (Z)-3-(4-(methylsulfonyl)benzylidene)isobenzofuran-1(3H)-one of potential pharmacological interest

    Regio- and Stereoselective Alkylation of Pyridine‑<i>N</i>‑oxides: Synthesis of Substituted Piperidines and Pyridines

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    Regio- and stereoselective addition of alkyl Grignard reagents to pyridine-<i>N</i>-oxides gave C2-alkylated <i>N</i>-hydroxy-1,2,5,6-tetrahydropyridines and <i>trans</i>-2,3-disubstituted <i>N</i>-hydroxy-1,2,5,6-tetrahydropyridines in good to excellent yields. These intermediates were aromatized or alternatively reduced in one-pot methodologies for efficient syntheses of alkylpyridines or piperidines, respectively. These reactions have a broad substrate scope and short reaction times

    Ultrasound Assisted Cu-catalyzed Ullmann-Goldberg Type Coupling-cyclization in a Single Pot: Synthesis and inSsilico Evaluation of 11H-pyrido[2,1-b]quinazolin-11-ones Against SARS-CoV-2 RdRp

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    The in silico evaluation of 11H-pyrido[2,1-b]quinazolin-11-one derivatives against SARS-CoV-2 RdRp was undertaken based on the reports on antiviral activities of this class of compounds in addition to the promising interactions of the antiviral drug penciclovir as well as quinazoline derivatives with SARS-CoV-2 RdRp in silico. The target compounds were prepared via an Ullmann–Goldberg type coupling followed by the subsequent cyclization (involving amidation) in a single pot. The methodology involved a CuI-catalyzed reaction of 2-iodobenzoate ester with 2-aminopyridine or quinolin-2-amine or thiazol-2-amine under ultrasound to give the expected products in acceptable (51–93%) yields. The molecular interactions of the synthesized 11H-pyrido[2,1-b]quinazolin-11-one derivatives with the SARS-CoV-2 RdRp (PDB: 7AAP) were evaluated in silico. The study suggested that though none of these compounds showed interactions better than penciclovir but the compound 3a and 3n appeared to be comparable along with 3b seemed to be nearly comparable to favipiravir and remdesivir. The compound 3n with the best binding energy (-79.85 Kcal/mol) participated in the H-bond interactions through its OMe group with THR556 as well as ARG624 and via the N-5 atom with the residue SER682. The in silico studies further suggested that majority of the compounds interacted with the main cavity of active site pocket whereas 3h and 3o that showed relatively lower binding energies (-66.06 and -66.28 Kcal/mol) interacted with the shallow cavity underneath the active site of SARS CoV-2 RdRp. The study also revealed that a OMe group was favourable for interaction with respect to its position in the order C-8 \u3e C-1 \u3e C-2. Further, the presence of a fused quinoline ring was tolerated whereas a fused thiazole ring decreased the interaction significantly. The in silico predictions of pharmacokinetic properties of 3a, 3b and 3n indicated that besides the BBB (Blood Brain Barrier) penetration potential these molecules may show a good overall ADME. Overall, the regioisomers 3a, 3b and 3n have emerged as molecules of possible interest in the context of targeting COVID-19

    Techniques and methods of assessing projects including inflation

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    Навчальний посібник виготовлено відповідно до програми з нормативної навчальної дисципліни "Фінансовий менеджмент", яку включено до навчального плану підгтовки освітньо-кваліфікаційного рівня "спеціаліст" і "магістр" спеціальностей. У ньому викладено сутність і завдання фінансового менеджменту, підходи до управління активами, капіталом, інвестиціями, фінансовими ризиками підприємства, основи управління вартістю бізнесу.The book is made in accordance with the program of regulatory discipline "Financial Management", which is included in the educational program for qualification of "expert" and "master" specialties. It outlines the nature and objectives of financial management, approaches to asset management, capital investment, financial risk companies, foundations of business value

    Synthesis of Isocoumarin Derivatives via the Copper-Catalyzed Tandem Sequential Cyclization of 2- Halo-<i>N</i>-phenyl Benzamides and Acyclic 1,3-Diketones

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    A facile and rapid synthesis of isocoumarin derivatives using a copper-catalyzed tandem C–C/C–O coupling strategy from readily available substrates is described. The reactions of a wide range of 2-iodo-<i>N</i>-phenyl benzamides and acyclic diketones as starting materials were investigated

    Synthesis of Isocoumarin Derivatives via the Copper-Catalyzed Tandem Sequential Cyclization of 2- Halo-<i>N</i>-phenyl Benzamides and Acyclic 1,3-Diketones

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    A facile and rapid synthesis of isocoumarin derivatives using a copper-catalyzed tandem C–C/C–O coupling strategy from readily available substrates is described. The reactions of a wide range of 2-iodo-<i>N</i>-phenyl benzamides and acyclic diketones as starting materials were investigated

    Synthesis of Isocoumarin Derivatives via the Copper-Catalyzed Tandem Sequential Cyclization of 2- Halo-<i>N</i>-phenyl Benzamides and Acyclic 1,3-Diketones

    No full text
    A facile and rapid synthesis of isocoumarin derivatives using a copper-catalyzed tandem C–C/C–O coupling strategy from readily available substrates is described. The reactions of a wide range of 2-iodo-<i>N</i>-phenyl benzamides and acyclic diketones as starting materials were investigated

    A role for the auxin precursor anthranilic acid in root gravitropism via regulation of PIN‐FORMED protein polarity and relocalisation in Arabidopsis

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    Distribution of auxin within plant tissues is of great importance for developmental plasticity, including root gravitropic growth. Auxin flow is directed by the subcellular polar distribution and dynamic relocalisation of auxin transporters such as the PIN‐FORMED (PIN) efflux carriers, which can be influenced by the main natural plant auxin indole‐3‐acetic acid (IAA). Anthranilic acid (AA) is an important early precursor of IAA and previously published studies with AA analogues have suggested that AA may also regulate PIN localisation. Using Arabidopsis thaliana as a model species, we studied an AA‐deficient mutant displaying agravitropic root growth, treated seedlings with AA and AA analogues and transformed lines to over‐produce AA while inhibiting its conversion to downstream IAA precursors. We showed that AA rescues root gravitropic growth in the AA‐deficient mutant at concentrations that do not rescue IAA levels. Overproduction of AA affects root gravitropism without affecting IAA levels. Treatments with, or deficiency in, AA result in defects in PIN polarity and gravistimulus‐induced PIN relocalisation in root cells. Our results revealed a previously unknown role for AA in the regulation of PIN subcellular localisation and dynamics involved in root gravitropism, which is independent of its better known role in IAA biosynthesis
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