Modification Of Chains Research Articles

Subcellular coordination of plant cell wall synthesis.

Organelles of the plant cell cooperate to synthesize and secrete a strong yet flexible polysaccharide-based extracellular matrix: the cell wall. Cell wall composition varies among plant species, across cell types within a plant, within different regions of a single cell wall, and in response to intrinsic or extrinsic signals. This diversity in cell wall makeup is underpinned by common cellular mechanisms for cell wall production. Cellulose synthase complexes function at the plasma membrane and deposit their product into the cell wall. Matrix polysaccharides are synthesized by a multitude of glycosyltransferases in hundreds of mobile Golgi stacks, and an extensive set of vesicle trafficking proteins govern secretion to the cell wall. In this review, we discuss the different subcellular locations at which cell wall synthesis occurs, review the molecular mechanisms that control cell wall biosynthesis, and examine how these are regulated in response to different perturbations to maintain cell wall homeostasis.

Understanding Electric Field‐Dependent Structure Variation of Functional Ionic Liquids at the Electrode Interface

AbstractUnderstanding the electric field‐dependent structure variation of ionic liquids (ILs) near electrodes is crucial to the rational design of ILs‐based electrochemical applications. In the present work, the number density and ionic orientation show that anions in imidazole ILs accumulate first and then are pulled out while that in sulfonic imidazole ILs changes little as the electric field strengthens. Meanwhile, the evolution of layered structure of cation and anion leads to a stronger interfacial polarization compared to that in the bulk for various ILs. Moreover, the elongation and sulfonic modification of the side chain can further respectively strengthen and weaken the interfacial polarization. These quantitative relations among structure change, side‐chain length, sulfonic group, and the electric field can provide practical guidelines in the ionic liquid design and management of the related electrochemical processes.

Naphthalenothiophene imide-based polymer exhibiting over 17% efficiency

Summary Developing novel electron-deficient monomers is crucially important for the future development of non-fullerene organic solar cells. Here, we report a new electron-deficient monomer naphthalenothiophene imide (NTI) and NTI-based copolymers PNTB and PNTB-2T. The strong electron-withdrawing ability of NTI could effectively lower the HOMO level of the polymer that facilitates the tuning of the polymer’s physical properties while simultaneously maintaining the low-lying HOMO value. Polymer chains modification by introducing extra thiophenes results in the closed π−π stacking and ordered polymer chain packing of PNTB-2T and is proven to be an effective strategy to increase the device performance. Thus, solar cell devices for PNTB-2T:Y6 exhibit an efficiency of 16.72%, which is further enhanced to 17.35% by the third component PC71BM, whereas that for PNTB:Y6 is only 3.81%. Importantly, PNTB-2T-based devices exhibit excellent batch-to-batch reproducibility. These features make this family of polymer donors very promising and the design strategies will enlighten future development of high-performance polymer donors for organic solar cells (OSC).

Изменение бизнес-моделей в условиях цифровой трансформации мировой экономики

Technological advances have resulted in rapid decrease of the data processing unit cost, which has stimulated a significant increase in the use of digital information that can be manipulated at a high speed and with low marginal costs. This change facilitated the use and integration of digital products and transactions, which led to continuous structural transformation of the economy. Digital technologies are increasingly blurring the boundaries between human life and information technologies, which requires a systemic approach to innovative business models, but so far general concept and unified methodology for systemic development of digital business models are missing. The present article summarizes the main approaches to analyzing changes in business models under the influence of digital transformation. The latter has led both to modification of global value chains and to the development of a new type of global digital platforms operating based on a new system of competitive advantages.

Nanopore-Based Localization of Post-Translational Modification Mimic

Post-translational modifications (PTMs) of proteins modulate folding, alter stability, and change interactions with ligands and are thus a primary feature of cell signaling pathways. PTMs can exist as covalent amino acid side chain modifications or alterations to the length and composition of the polypeptide chain termini. Here we probe the effect of PTMs on α-synuclein (αSyn) voltage-induced interactions with the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. The divalent Alexa Fluor 488 sidechain was attached separately at two positions on the αSyn C-terminal domain and serves as a PTM mimic.

Bicyclic Ligand-Biased Agonists of S1P1: Exploring Side Chain Modifications to Modulate the PK, PD, and Safety Profiles.

Sphingosine-1-phosphate (S1P) binds to a family of sphingosine-1-phosphate G-protein-coupled receptors (S1P1-5). The interaction of S1P with these S1P receptors has a fundamental role in many physiological processes in the vascular and immune systems. Agonist-induced functional antagonism of S1P1 has been shown to result in lymphopenia. As a result, agonists of this type hold promise as therapeutics for autoimmune disorders. The previously disclosed differentiated S1P1 modulator BMS-986104 (1) exhibited improved preclinical cardiovascular and pulmonary safety profiles as compared to earlier full agonists of S1P1; however, it demonstrated a long pharmacokinetic half-life (T1/2 18 days) in the clinic and limited formation of the desired active phosphate metabolite. Optimization of this series through incorporation of olefins, ethers, thioethers, and glycols into the alkyl side chain afforded an opportunity to reduce the projected human T1/2 and improve the formation of the active phosphate metabolite while maintaining efficacy as well as the improved safety profile. These efforts led to the discovery of 12 and 24, each of which are highly potent, biased agonists of S1P1. These compounds not only exhibited shorter in vivo T1/2 in multiple species but are also projected to have significantly shorter T1/2 values in humans when compared to our first clinical candidate. In models of arthritis, treatment with 12 and 24 demonstrated robust efficacy.

The Effect of Alkyl Spacers on the Mixed Ionic‐Electronic Conduction Properties of N‐Type Polymers

AbstractConjugated polymers with mixed ionic and electronic transport are essential for developing the complexity and function of electrochemical devices. Current n‐type materials have a narrow scope and low performance compared with their p‐type counterparts, requiring new molecular design strategies. This work presents two naphthalene diimide‐bithiophene (NDI‐T2) copolymers functionalized with hybrid alkyl‐glycol side chains, where the naphthalene diimide unit is segregated from the ethylene glycol (EG) units within the side chain by an alkyl spacer. Introduction of hydrophobic propyl and hexyl spacers is investigated as a strategy to minimize detrimental swelling close to the conjugated backbone and balance the mixed conduction properties of n‐type materials in aqueous electrolytes. It is found that both polymers functionalized with alkyl spacers outperform their analogue bearing EG‐only side chains in organic electrochemical transistors (OECTs). The presence of the alkyl spacers also leads to remarkable stability in OECTs, with no decrease in the ON current after 2 h of operation. Through this versatile side chain modification, this work provides a greater understanding of the structure‐property relationships required for n‐type OECT materials operating in aqueous media.

AP2/ERF transcription factors orchestrate very long chain fatty acid biosynthesis during Arabidopsis lateral root development

AP2/ERF transcription factors orchestrate very long chain fatty acid biosynthesis during Arabidopsis lateral root development

Vitamin E Derivative with Modified Side Chain Induced Apoptosis by Modulating the Cellular Lipids and Membrane Dynamics in MCF7 Cells.

The vitamin E derivative with side chain modification (TC6OAc) has been shown to possess anticancer activity in our earlier in vivo studies. It was hypothesized that, as Vitamin E (VE) and VE derivative are fat soluble lipophilic molecules, they exert their function by modulating the lipid metabolism and related pathways. This study aimed to evaluate the cellular impact of this VE derivative (2,5,7,8-Tetramethyl-2-(4'-Methyl-3'-Pentenyl)-6-Acetoxy Chromane-TC6OH), using α-tocopherol as a reference compound throughout the experiments. Their effects on the cellular metabolism, the biophysical properties of cellular lipids and the functional characteristics of cells were monitored in human estrogen receptor (ER) positive breast cancer cells. It has been documented that TC6OH treatment induces tumor cell apoptosis by dissipating the mitochondrial membrane potential, modulating the lipid, transportation and degradation as well as downregulating certain anti-apoptotic and growth factor related proteins. Due to resistance of ER positive cells to the established therapies, the findings of this study are of translational value.

PECULIARITIES OF BUILDING THE VALUE CHAIN OF THE IT-INDUSTRY OUTSOURCING ENTERPRISES

The active development of information and communication technologies and the enhancement of their impact on the world economy requires the search for new and adaptation of existing tools and mechanisms of competitiveness management for the needs of the IT-industry subjects. The peculiarities of building the value chain of the IT-industry enterprises have been considered and the volumes of the global IT-companies market have been analyzed. When using the value chain concept, an enterprise has the ability to identify and focus efforts on generating high-order competitive advantages, which are relevant for high-tech IT-companies. The value creation chain helps to divide all kinds of activities into strategic groups for a detailed analysis of the company, on the basis of which managers can better evaluate the stages at which the value of the product is created and where the work of the enterprise can be optimized.
 The necessity of adjusting the management of these IT-companies to determine their competitive advantages has been substantiated. The competitiveness of the company has been evaluated in the context of the influence of the main competitive forces and the main threats have been identified. The directions of value chain modification for the needs of TEAM International Services Inc. have been determined. An IT-industry value chain has been offered. It consistently demonstrates the main and accompanying activities that shape product value on the example of US outsourcing company TEAM International Services Inc. It is defined that in the process of building a value chain for an outsourced IT-company, it is expedient to take into account the main stages of a software product pricing. Such approach allows influence the company competitiveness, isolate sources of international competitive advantages of the IT-industry enterprises, namely: continuous technological modernization, use of qualitative licensed software, adaptability of corporate policy and culture, wide opportunities for company employees.

Detection of 30 Fentanyl Analogs by Commercial Immunoassay Kits.

Health-care workers, laboratorians and overdose prevention centers rely on commercial immunoassays to detect the presence of fentanyl; however, the cross-reactivity of fentanyl analogs with these kits is largely unknown. To address this, we conducted a pilot study evaluating the detection of 30 fentanyl analogs and metabolites by 19 commercially available kits (9 lateral flow assays, 7 heterogeneous immunoassays and 3 homogenous immunoassays). The analogs selected for analysis were compiled from the Drug Enforcement Administration and National Forensic Laboratory Information System reports from 2015 to 2018. In general, the immunoassays tested were able to detect their intended fentanyl analog and some closely related analogs, but more structurally diverse analogs, including 4-methoxy-butyryl fentanyl and 3-methylfentanyl, were not well detected. Carfentanil was only detected by kits specifically designed for its recognition. In general, analogs with group additions to the piperidine, or bulky rings or long alkyl chain modifications in the N-aryl or alkyl amide regions, were poorly detected compared to other types of modifications. This preliminary information is useful for screening diagnostic, forensic and unknown powder samples for the presence of fentanyl analogs and guiding future testing improvements.

The effect of the thermal aging on polycarbonate

Polycarbonate (PC) is a widely used amorphous polymer. Among its many interesting properties, we can mention, among others, transparency, impact resistance and low density. However, long exposure to temperature changes its physicochemical, thermal and mechanical properties. The aim of this study is to reveal the effect of the time of exposure to temperature, in air, on the properties of the PC. Thus, maintaining this material at 80 °C causes damage as revealed by Fourier transform infrared spectroscopy (FTIR) and microstructural observations by scanning electron microscopy (SEM). The thermal analyzes also made it possible to observe modifications of the molecular chains as well as modifications of the mechanical properties confirmed by mechanical tests.

Different roles for the acyl chain and the amine leaving group in the substrate selectivity of N-Acylethanolamine acid amidase

N-acylethanolamine acid amidase (NAAA) is an N-terminal nucleophile (Ntn) hydrolase that catalyses the intracellular deactivation of the endogenous analgesic and anti-inflammatory agent palmitoylethanolamide (PEA). NAAA inhibitors counteract this process and exert marked therapeutic effects in animal models of pain, inflammation and neurodegeneration. While it is known that NAAA preferentially hydrolyses saturated fatty acid ethanolamides (FAEs), a detailed profile of the relationship between catalytic efficiency and fatty acid-chain length is still lacking. In this report, we combined enzymatic and molecular modelling approaches to determine the effects of acyl chain and polar head modifications on substrate recognition and hydrolysis by NAAA. The results show that, in both saturated and monounsaturated FAEs, the catalytic efficiency is strictly dependent upon fatty acyl chain length, whereas there is a wider tolerance for modifications of the polar heads. This relationship reflects the relative stability of enzyme-substrate complexes in molecular dynamics simulations.

Effect of roasting temperature on lipid and protein oxidation and amino acid residue side chain modification of beef patties.

Beef is rich in nutrients and is one of the most important ingredients in the world. But in the process of cooking and heating, the nutrients of beef will change to varying degrees. How temperature affects the oxidation of lipids and proteins in beef, and the modification of amino acid residues is unclear. This study intended to heat beef at different roasting temperatures (150 °C, 190 °C, 230 °C, 270 °C, 310 °C), measure parameter including colour, peroxide value (PV), thiobarbituric acid-reactive substances (TBARS), thiol and carbonyl content, protein solubility, tryptophan and Schiff base content, protein molecular weight distribution and modification of amino acid residues to discussed the effects of different temperatures on the lipid and protein oxidation of beef patties, as well as the modification of amino acid residues. The results showed that the values of L* and b* increased with the temperature increased, and the values of a* decreased. With the increase of temperature, the lipid oxidation indexes PV and TBARS, Schiff base and carbonyl content also increased, and the thiol content and protein solubility decreased significantly (p < 0.001). SDS-PAGE showed that the band of myosin heavy chain (MHC, 220 kDa) was significantly degraded, while the band of actin (42 kDa) was still clearly visible. The analysis of UPLC-MS/MS results found that the aromatic amino acid residues in all samples were oxidized to a certain extent, especially tryptophan. Other oxidative modifications, including α-amiooadipic acid (AAA), hydroxyethyl lysine (CEL) and malondialdehyde (MDA), were only present in roasted samples and not in raw meat. The results suggested that lipid oxidation and protein oxidation were closely related to colour parameters. The oxidation of proteins and lipids was aggravated at higher temperature. Amino acid side chains were also modified at high temperature, and this change was particularly evident in aromatic amino acids. These results provided new insights for the oxidation of proteins and lipids of beef and the modification level of amino acid residues under high temperature conditions, which will help us to improve the cooking quality of meat foods.

Unusual low temperature relaxation behavior of crosslinked acrylonitrile-butadiene co-polymer

Conventional crosslinking of rubbers (using sulphur and peroxide vulcanization) usually leads to covalent rubber network junctions. The present article reports about a new unconventional crosslinking of acrylonitrile butadiene copolymer (NBR) by zinc chloride (ZnCl2). This crosslinked NBR displayed very interesting relaxation properties below the glass transition temperature. In this work, detailed chemical mechanistic pathways were suggested and correlated with the low-temperature relaxation dynamics of the crosslinked material. Fourier-transform infrared spectroscopy analysis clearly indicated a coordination effect between zinc and nitrile groups. At lower temperatures, beside the glass transition, another relaxation process (β relaxation) was detected. Interestingly, a hydrolyzed crosslinked sample showed even two other additional relaxation processes. The origin of such relaxations was critically discussed from the viewpoints of modification of the polymer chains as well as low molecular weight fragments of the polymer.

Hydrophobicity-Adjustable MOF Constructs Superhydrophobic MOF-rGO Aerogel for Efficient Oil-Water Separation.

Accurate hydrophobicity adjustment of single-phase material is quite challenging and meaningful for water treatment. Here, a strategy combining crystal morphology regulation and post-synthetic modification is reported based on a novel metal-organic framework (MOF, Eu-bdo-COOH, H4bdo = 2,5-bis(3,5-dicarboxylphenyl)-1,3,4-oxadiazole). The hydrophobicity is regulated by crystal size and morphology regulation, and a rough microspherical MOF is successfully synthesized. Meanwhile, the obtained MOF microspheres exhibit high water, chemical, and thermal stability. The post-synthetic modification of alkyl chains achieves fine-tuning of hydrophobicity of MOF microspheres. The static water contact angles can controllably range from 43 to 142°, and the amylamine-modified MOF (AM) obtains the strongest hydrophobicity. In addition, a superhydrophobic aerogel is constructed with AM microspheres and reduced graphene oxide (rGO) for efficient oil-water separation. The AM-rGO aerogel (AM-rGA) exhibits fast and efficient absorption of various oily substances from water, and the adsorption capacity of dibromoethane reaches up to 14,728 wt %. This outstanding oil adsorption capacity can maintain even beyond 50 cycles by the support of the stable aerogel. The strategy of morphology regulation and post-synthetic modification provides a broad approach for the hydrophobic adjustment of numerous MOF materials.

Brassicaceae transcriptomes reveal convergent evolution of super-accumulation of sinigrin

Wasabi, horseradish and mustard are popular pungent crops in which the characteristic bioactive hydrolysis of specialized glucosinolates (GSLs) occurs. Although the metabolic pathways of GSLs are well elucidated, how plants have evolved convergent mechanisms to accumulate identical GSL components remains largely unknown. In this study, we discovered that sinigrin is predominantly synthesized in wasabi, horseradish and mustard in Brassicaceae. We de novo assembled the transcriptomes of the three species, revealing the expression patterns of gene clusters associated with chain elongation, side chain modification and transport. Our analysis further revealed that several gene clusters were convergently selected during evolution, exhibiting convergent shifts in amino acid preferences in mustard, wasabi and horseradish. Collectively, our findings provide insights into how unrelated crop species evolve the capacity for sinigrin super-accumulation and thus promise a potent strategy for engineering metabolic pathways at multiple checkpoints to fortify bioactive compounds for condiment or pharmaceutical purposes.

Novel Photoreactive Pressure-Sensitive Adhesives (PSA) Based on Acrylics Containing Additionable Photoinitiators.

A new class of additionable ultraviolet photoinitiators that can be used, through addition, for modification of the acrylic polymer chain and their influence of main properties of acrylic pressure-sensitive adhesives (PSAs) is described here. The photoinitiators studied are based on benzophenone, dibenzofuran and anthraquinone chromophores. The propyleneimine carbonyl is the reactive additionable group incorporated in the photoinitiator structure. First, the solvent-borne acrylic pressure-sensitive adhesive was synthesized and characterized. Then, a photoinitiator suitable for addition to the acrylic polymer chain possessing a carboxyl group was added before UV-irradiation. A mechanism of UV-initiated cross-linking reaction of acrylic PSA with additionable photoinitiators was done as well. The influence of the concentration and type of photoinitiator, UV-crosslinking time and UV-dose on peel adhesion, shear strength and tack of solvent-borne acrylic pressure-sensitive adhesives cross-linked by UV light was studied and presented here. It was found that the tack depends on the UV-dose and photoinitiator concentration. An increase of UV dose results in an increase of shear strength of acrylic pressure-sensitive adhesive (PSA) formulations.

Tissue Expression of Atrial and Ventricular Myosin Light Chains in the Mechanism of Adaptation to Oxidative Stress

Ischemia/reperfusion (I/R) injury induces post-translational modifications of myosin light chains (MLCs), increasing their susceptibility to degradation by matrix metalloproteinase 2 (MMP-2). This results in the degradation of ventricular light chains (VLC1) in heart ventricles. The aim of the study was to investigate changes in MLCs content in the mechanism of adaptation to oxidative stress during I/R. Rat hearts, perfused using the Langendorff method, were subjected to I/R. The control group was maintained in oxygen conditions. Lactate dehydrogenase (LDH) activity and reactive oxygen/nitrogen species (ROS/RNS) content were measured in coronary effluents. Atrial light chains (ALC1) and ventricular light chains (VLC1) gene expression were examined using RQ-PCR. ALC1 and VLC1 protein content were measured using ELISA tests. MMP-2 activity was assessed by zymography. LDH activity as well as ROS/RNS content in coronary effluents was higher in the I/R group (p = 0.01, p = 0.04, respectively), confirming heart injury due to increased oxidative stress. MMP-2 activity in heart homogenates was also higher in the I/R group (p = 0.04). ALC1 gene expression and protein synthesis were significantly increased in I/R ventricles (p < 0.01, 0.04, respectively). VLC1 content in coronary effluents was increased in the I/R group (p = 0.02), confirming the increased degradation of VLC1 by MMP-2 and probably an adaptive production of ALC1 during I/R. This mechanism of adaptation to oxidative stress led to improved heart mechanical function.

3-O-sulfated heparan sulfate interactors target synaptic adhesion molecules from neonatal mouse brain and inhibit neural activity and synaptogenesis in vitro

Heparan sulfate (HS) chains, covalently linked to heparan sulfate proteoglycans (HSPG), promote synaptic development and functions by connecting various synaptic adhesion proteins (AP). HS binding to AP could vary according to modifications of HS chains by different sulfotransferases. 3-O-sulfotransferases (Hs3sts) produce rare 3-O-sulfated HSs (3S-HSs), of poorly known functions in the nervous system. Here, we showed that a peptide known to block herpes simplex virus by interfering with 3S-HSs in vitro and in vivo (i.e. G2 peptide), specifically inhibited neural activity, reduced evoked glutamate release, and impaired synaptic assembly in hippocampal cell cultures. A role for 3S-HSs in promoting synaptic assembly and neural activity is consistent with the synaptic interactome of G2 peptide, and with the detection of Hs3sts and their products in synapses of cultured neurons and in synaptosomes prepared from developing brains. Our study suggests that 3S-HSs acting as receptors for herpesviruses might be important regulators of neuronal and synaptic development in vertebrates.