A Model of the Full-Length Cytokinin Receptor: New Insights and Prospects.

Cytokinins (CK) are one of the most important classes of phytohormones that regulate a wide range of processes in plants. A CK receptor, a sensor hybrid histidine kinase, was discovered more than 20 years ago, but the structural basis for its signaling is still a challenge for plant biologists. To date, only two fragments of the CK receptor structure, the sensory module and the receiver domain, were experimentally resolved.

The cytokinin receptor OHK4/OsHK4 regulates inflorescence architecture in rice via an IDEAL PLANT ARCHITECTURE1/WEALTHY FARMER'S PANICLE-mediated positive feedback circuit.

Inflorescence architecture is important for rice (Oryza sativa) grain yield. The phytohormone cytokinin (CK) has been shown to regulate rice inflorescence development; however, the underlying mechanism mediated by CK perception is still unclear. Employing a forward genetic approach, we isolated an inactive variant of the CK receptor OHK4/OsHK4 gene named panicle length1, which shows decreased panicle size due to reduced inflorescence meristem (IM) activity.

Canonical and Alternative Auxin Signaling Systems in Mono-, Di-, and Tetraploid Potatoes.

It has long been known that the phytohormone auxin plays a promoting role in tuber formation and stress tolerance in potatoes. Our study aimed to identify and characterize the complete sets of auxin-related genes that presumably constitute the entire auxin signaling system in potato ( L.).

In Planta, In Vitro and In Silico Studies of Chiral -Benzyladenine Derivatives: Discovery of Receptor-Specific -Enantiomers with Cytokinin or Anticytokinin Activities.

Cytokinins, classical phytohormones, affect all stages of plant ontogenesis, but their application in agriculture is limited because of the lack of appropriate ligands, including those specific for individual cytokinin receptors. In this work, a series of chiral -benzyladenine derivatives were studied as potential cytokinins or anticytokinins. All compounds contained a methyl group at the α-carbon atom of the benzyl moiety, making them - or -enantiomers.

Carbon Quantum Dots' Synthesis with a Strong Chemical Claw for Five Transition Metal Sensing in the Irving-Williams Series.

Carbon quantum dots (CQDs) are an excellent eco-friendly fluorescence material, ideal for various ecological testing systems. Herein, we establish uniform microwave synthesis of the group of carbon quantum dots with specific functionalization of ethylenediamine, diethylenetriamine, and three types of Trilon (A, B and C) with chelate claws -C-NH. CQDs' properties were studied and applied in order to sense metal cations in an aquatic environment.

Cytokinin Perception in Ancient Plants beyond Angiospermae.

Cytokinins (CKs) control many plant developmental processes and responses to environmental cues. Although the CK signaling is well understood, we are only beginning to decipher its evolution. Here, we investigated the CK perception apparatus in early-divergent plant species such as bryophyte , lycophyte , and gymnosperm .

Global View on the Cytokinin Regulatory System in Potato.

Cytokinins (CKs) were earlier shown to promote potato tuberization. Our study aimed to identify and characterize CK-related genes which constitute CK regulatory system in the core potato () genome. For that, CK-related genes were retrieved from the sequenced genome of the doubled monoploid (DM) Phureja group, classified and compared with Arabidopsis orthologs.

Ascorbic Acid-Assisted Polyol Synthesis of Iron and Fe/GO, Fe/h-BN Composites for Pb Removal from Wastewaters.

Iron powders and Fe/graphene oxide and Fe/boron nitride composites were synthesized by means of a polyol synthesis method. The effect of NaOH/Fe and ascorbic acid/Fe ratios on the characteristics of synthesized products were evaluated. The samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, low-temperature nitrogen adsorption and Raman-spectroscopy.

Modeling of Protein⁻Protein Interactions in Cytokinin Signal Transduction.

The signaling of cytokinins (CKs), classical plant hormones, is based on the interaction of proteins that constitute the multistep phosphorelay system (MSP): catalytic receptors-sensor histidine kinases (HKs), phosphotransmitters (HPts), and transcription factors-response regulators (RRs). Any CK receptor was shown to interact in vivo with any of the studied HPts and . In addition, both of these proteins tend to form a homodimer or a heterodimeric complex with protein-paralog.

Auxins in potato: molecular aspects and emerging roles in tuber formation and stress resistance.

The study of the effects of auxins on potato tuberization corresponds to one of the oldest experimental systems in plant biology, which has remained relevant for over 70 years. However, only recently, in the postgenomic era, the role of auxin in tuber formation and other vital processes in potatoes has begun to emerge. This review describes the main results obtained over the entire period of auxin-potato research, including the effects of exogenous auxin; the content and dynamics of endogenous auxins; the effects of manipulating endogenous auxin content; the molecular mechanisms of auxin signaling, transport and inactivation; the role and position of auxin among other tuberigenic factors; the effects of auxin on tuber dormancy; the prospects for auxin use in potato biotechnology.

Cytokinin perception in potato: new features of canonical players.

Potato is the most economically important non-cereal food crop. Tuber formation in potato is regulated by phytohormones, cytokinins (CKs) in particular. The present work studied CK signal perception in potato.

Studies of cytokinin receptor-phosphotransmitter interaction provide evidences for the initiation of cytokinin signalling in the endoplasmic reticulum.

Cytokinin receptors were shown recently to be localised mainly to the endoplasmic reticulum (ER); however, the activity of ER-located receptors was not proven. We have therefore tested the functionality of ER-located Arabidopsis receptors. The first step of cytokinin signal transduction is the transfer of a phosphoryl group from the activated receptor to a phosphotransfer protein.

Controlling photophysics of styrylnaphthalimides through TICT, fluorescence and E,Z-photoisomerization interplay.

The photophysical properties of naphthalimide dyes NI1-3 with electron releasing 4-methoxy- (NI1), 3,4-dimethoxystyryl- (NI2) and dimethylaminostyryl (NI3) groups are examined in a variety of protic and aprotic solvents. All compounds demonstrate positive solvatochromism in the steady-state absorption and fluorescence spectra. The analysis of the dependence of the Stokes shift on the polarity of the solvent using the Lippert-Mataga equation allowed us to determine the change in the dipole moment upon excitation.

Cage-like copper(II) silsesquioxanes: transmetalation reactions and structural, quantum chemical, and catalytic studies.

The transmetalation of bimetallic copper-sodium silsesquioxane cages, namely, [(PhSiO1.5 )10 (CuO)2 (NaO0.5 )2 ] ("Cooling Tower"; 1), [(PhSiO1.

Dihydrogen bond intermediated alcoholysis of dimethylamine-borane in nonaqueous media.

Dimethylamine-borane (DMAB) acid/base properties, its dihydrogen-bonded (DHB) complexes and proton transfer reaction in nonaqueous media were investigated both experimentally (IR, UV/vis, NMR, and X-ray) and theoretically (DFT, NBO, QTAIM, and NCI). The effects of DMAB concentration, solvents polarity and temperature on the degree of DMAB self-association are shown and the enthalpy of association is determined experimentally for the first time (-ΔH°assoc = 1.5-2.

Plant membrane assays with cytokinin receptors underpin the unique role of free cytokinin bases as biologically active ligands.

Cytokinin receptors play a key role in cytokinin-dependent processes regulating plant growth, development, and adaptation; therefore, the functional properties of these receptors are of great importance. Previously the properties of cytokinin receptors were investigated in heterologous assay systems using unicellular microorganisms, mainly bacteria, expressing receptor proteins. However, within microorganisms receptors reside in an alien environment that might distort the receptor properties.

Difluoromethylene phosphabetaine as an equivalent of difluoromethyl carbanion.

A method for nucleophilic difluoromethylation of reactive Michael acceptors, aldehydes, and azomethines is described. The reaction is performed using the readily available and air-stable reagent difluoromethylene phosphabetaine. The process involves interaction of an electrophilic substrate with in situ generated difluorinated phosphonium ylide followed by hydrolysis of the carbon-phosphorus bond under mild conditions.

Synthesis of gem-difluorinated nitroso compounds.

A method for the synthesis of gem-difluorinated nitroso compounds is described. The reaction involves interaction of organozinc reagents with (bromodifluoromethyl)trimethylsilane followed by nitrosation of difluorinated organozinc species with an n-butyl nitrite/chlorotrimethylsilane system.

Geminal silicon/zinc reagent as an equivalent of difluoromethylene bis-carbanion.

A new difluorinated reagent, [difluoro(trimethylsilyl)methyl]zinc bromide, bearing C-Zn and C-Si bonds is described. The reagent is conveniently prepared by cobalt-catalyzed halogen/zinc exchange. It can be coupled with two different C-electrophiles in a stepwise manner (with allylic halides for C-Zn bond and aldehydes for C-Si bond) affording products containing a difluoromethylene fragment.

Solvent-controlled synthesis of tetranuclear cage-like copper(II) silsesquioxanes. Remarkable features of the cage structures and their high catalytic activity in oxidation with peroxides.

Two principally different in their molecular architecture isomeric tetranuclear copper(ii) silsesquioxanes, "Globule"-like compound [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1) and "Sandwich"-like derivative [(PhSiO1.

Fluorocyanation of enamines.

A method for the fluorocyanation of enamines has been described. The reaction involves fluorination of the electron rich double bond with N-F reagent (Selectfluor or NFSI) accompanied by trapping of beta-fluoroiminium cationic intermediate with cyanide nucleophile.

Four independent structures of a pentacoordinate silicon species at different points on the Berry pseudorotation pathway.

A new pentacoordinate silicon species containing two chelating ligands has been synthesized. The structures of four independent cations of the same compound correspond to different points on the Berry pseudorotation pathway. The percentage of square planar character varies between 19% and 40%.

Trifluoromethylation of N-benzoylhydrazones.

A method for the nucleophilic trifluoromethylation of N-benzoylhydrazones using Me3SiCF3/AcONa has been described. The CN bond of the hydrazones is activated by difluoroboron group, which is introduced by means of boron trifluoride and allylsilane.

Trifluoromethylation of salicyl aldimines.

A method for the nucleophilic trifluoromethylation of salicyl aldimines, which do not contain an activating group at the nitrogen atom, has been described. The reaction proceeds through the initial generation of intramolecular boron complex followed by interaction with Me3SiCF3 activated by sodium acetate.