The Processivity of Telomerase: Insights from Kinetic Simulations and Analyses

Telomerases are moderately processive reverse transcriptases that use an integral RNA template to extend the 3′ end of linear chromosomes. Processivity values, defined as the probability of extension rather than dissociation, range from about 0.7 to 0.99 at each step. Consequently, an average of tens to hundreds of nucleotides are incorporated before the single-stranded sDNA product dissociates. The RNA template includes a six nucleotide repeat, which must be reset in the active site via a series of translocation steps. Nucleotide addition associated with a translocation event shows a lower processivity (repeat addition processivity, RAP) than that at other positions (nucleotide addition processivity, NAP), giving rise to a characteristic strong band every 6th position when the product DNA is analyzed by gel electrophoresis. Here, we simulate basic reaction mechanisms and analyze the product concentrations using several standard procedures to show how the latter can give rise to systematic errors in the processivity estimate. Complete kinetic analysis of the time course of DNA product concentrations following a chase with excess unlabeled DNA primer (i.e., a pulse-chase experiment) provides the most rigorous approach. This analysis reveals that the higher product concentrations associated with RAP arise from a stalling of nucleotide incorporation reaction during translocation rather than an increased rate constant for the dissociation of DNA from the telomerase.

Synthesis of Aminooxy Glycoside Derivatives of the Outer Core Domain of Pseudomonas aeruginosa Lipopolysaccharide

Pseudomonas aeruginosa is a highly prevalent gram-negative bacterium that is becoming more difficult to treat because of increasing antibiotic resistance. As chemotherapeutic treatment options diminish, there is an increased need for vaccines. However, the creation of an effective P. aeruginosa vaccine has been elusive despite intensive efforts. Thus, new paradigms for vaccine antigens should be explored to develop effective vaccines. In these studies, we have focused on the synthesis of two L-rhamnose–bearing epitopes common to glycoforms I and II of the outer core domain of Pseudomonas aeruginosa lipopolysaccharide, α-L-Rha-(1→6)-α-D-Glc-(1→4)-α-D-GalN-(Ala)-α-aminooxy (3) and α-L-Rha-(1→3)-β-D-Glc-(1→3)-α-D-GalN-(Ala)-α-aminooxy (4), respectively. The target trisaccharides were both prepared starting from a suitably protected galactosamine glycoside, followed by successive deprotection and glycosylation with suitably protected D-glucose and L-rhamnose thioglycosides. Global deprotection resulted in the formation of targets 3 and 4 in 22 and 35% yield each. Care was required to modify basic reaction conditions to avoid early deprotection of the N-oxysuccinamido group. In summary, trisaccharides related to the L-rhamnose–bearing epitopes common to glycoforms I and II of the outer core domain of Pseudomonas aeruginosa lipopolysaccharide have been prepared as their aminooxy glycosides. The latter are expected to be useful in chemoselective oxime-based bioconjugation reactions to form Pseudomonas aeruginosa vaccines.

Mild synthesis of isoxazoline derivatives via an efficient [4 + 1] annulation reaction of transient nitrosoalkenes and sulfur ylides

An efficient [4 + 1] annulation between α-bromooximes and sulfur ylides via in situ generation of nitrosoalkenes under mild basic reaction conditions has been developed, providing an expeditious and scalable approach to synthesize biologically interesting isoxazoline derivatives with good to excellent yields.

Obedience in times of COVID-19 pandemics: a renewed governmentality of unease?

This article transects and articulates different disciplines and lines of thought in order to understand the redefinitions of the boundaries of political power in times of COVID-19, and the practices which may outlive the potential normalisation of the crisis when an efficient vaccine is discovered. We claim that the COVID-19 pandemic is an original form of governmentality by unease articulating three dimensions. First, the basic reaction of modern states when faced with uncertainty is to apply national-territorial logics of controls. Second, bureaucracies consider the virus as a danger to security and organise public health emergencies according to the rules of the game of national security, creating tensions between internal security, public health and the economy because policymakers may be unsure about the priorities and may prioritise border controls. Third, resistance against the chosen national policies show that people are not led by a politics of fear and/or protection, but rather their own concerns about themselves with peer-to-peer surveillance as a key element of their compliance. Contact tracing technologies and strategies of border controls are key elements to analyse. We do so in different contexts: the UK, the EU and Turkey.<br /><br />Key messages<br /><ul><li>The COVID-19 pandemic is an original form of governmentality by unease.</li><br /><li>The new COVID-19 approach of many Schengen states was to change their measures from ones which block people from travelling to ones which dissuade people from travelling on account of the consequences.</li><br /><li>The arena of public health provides opportunities for a wide variety to actors to enter the data collection sphere where their actions face less public resistance because of the variable success of the politics of fear project accompanying state measures to fight the pandemic.</li></ul>

STUDIES USING HPLC-PDA IN GABAPENTIN N-DERIVATIZATION REACTIONS WITH 9-FLUORENYLMETHYL CHLOROFORMATE (FMOC-CL)

FMOC-Cl is a derivatizing agent widely used both in N-protection reactions of a-amino acids as well as in quantification and detection of amino acids and related molecules using HPLC-PDA or fluorescence analysis. In this work we studied the reaction of FMOC-Cl with gabapentin. However, it was observed that the degradation of gabapentin-N-FMOC and FMOC-Cl to FMOC-OH occur simultaneously in presence of the basic reaction medium which is specific for gabapentin derivatization. The degradation reaction is accelerated in temperatures above 45 °C and also by the time of contact of the reactant and product with basic medium. In this study, gabapentin derivatization reactions were shown to be cleaner and more efficient when an FMOC-Cl/gabapentin ratio of 2:1 was used, at 25 °C over a period of 15 minutes.

Effects of Mono-Ammonium Phosphate and K-Humate Applications on Grain Yield and Phosphorus Uptake Efficiency of Bread Wheat Crop (Triticum aestivum L.)

Study was aimed to determine the effect of mono-ammonium phosphate (MAP, NH4H2PO4) and K-Humate application on grain yield and grain phosphorus uptake efficiency which applied on Central Anatolian calcareous and basic reaction soil. The research was conducted at Bahri Dağdaş Agricultural Research Institute field in dry conditions during 2018 - 19 to determine the effect of phosphorus doses @ 0, 17.5 and 35.0 kg ha-1 and K-Humate @ 0 and 12 kg ha-1 on Bayraktar 2000 variety of bread wheat crop grain yield, agronomic (AE), physiological (PE) and apparent recovery (AR) phosphorus uptake efficiency. Results of the research revealed that increased phosphorus rate, enhances grain yield and amount of grain phosphorus uptake increase, while the grain AE, PE and AR were decreasing significantly. Additionally, with the K-Humate application with respect to control, the grain yield was positively affected in P0 and P17.5, while the grain phosphorus uptake amount was increased by 13%, in the P35 application the grain yield and the grain phosphorus uptake amount decreased by 9% and 5% respectively. In another direction, with the K-Humate application depending on control, in P17.5 application grain AE and AR were increased by 13% and 12% respectively, while grain PE decreased by 54%. Besides, with the K-Humate application according to control and in the P35 application grain AE, PE and AR were decreased by 66%, 51% and 40% respectively.

Study on the mechanism of furfural to maleic acid oxidized by hydrogen peroxide in formic acid solution

Although the conversion of furfural to formic acid oxidized by H2O2 in formic acid is very high, the molecular mechanism remains unknown. This work describes the entire reaction process of the condensation reaction based on the density functional theory (DFT). It is found that H acts as a shuttle throughout most of the basic reaction steps during this transformation. Besides, Baeyer–Villiger oxidation and Baeyer–Villiger rearrangement are also discovered during this process with the opening of furan ring following afterward. The reactants, products and intermediates in the reaction process are optimized; all possible reaction paths are considered as well as the energy barriers to be overcome at each step. Thermochemical data concerned with the conversion of furfural to maleic acid showed that the maximum energy barrier at 378.15[Formula: see text]K was 39.83[Formula: see text]kcal/mol. The results of this study do not only correspond with the existing conclusions about the reaction in question from previous research but also supplement to the study of the pathways and mechanisms of the reaction, which can provide reference and guidance for further research, both experimentally and theoretically.

Towards a Framework to Create Shared Value Partnerships in the Community Evidence from Egypt

Government and non-government organizations (NGOs) basic reaction to the pace and scale of international changes has been a hesitancy to recognize adequately the need to modify themselves. Problems tend to be interdependent as well as bundled, needing thorough approaches as well as common participation. On the other hand, the private sector in developing countries providing on average 60 per cent of GDP, 80 per cent of capital flows and 90 per cent of jobs. As a result, a solid along with vital private sector is essential for help Developing countries move from associations depending on aid towards types depending on economic partnerships. Consequently, developing a collaboration dependent upon creating shared value (CSV) credo by using the private sector - rather than the conventional social responsibility approach- is a must to increase the impact involving aid investments while bringing in business growth. Hence, such paper aims to depict the suitable framework to create shared value policies and practices that enhance the competitiveness of private sector companies while simultaneously advancing the economic and social conditions in the communities in which they operate. Moreover, it tends to detect barriers impeding the realization of such framework; and the needed pillars to overcome such barriers in developing countries as Egypt.

Radical Functionalization of Thioglycosides in Aqueous Medium

<p>A visible-light-mediated thiol-ene reaction is successfully operated in aqueous medium. Organic photoredox catalyst (9-mesityl-10-methylacridinum tetrafluoroborate) is used to initiate the radical process to generate thiyl radicals upon light irradiation. Two reaction pathways are discovered in different aqueous buffer system. Thiol-ene adduct is preferred in acidity reaction medium; while disulfide formation is found to be favored in basic reaction medium. Moreover, a visible-light-mediated modified Danishefsky-Wan desulfurization is used to convert thioglycoside to highly substituted tetrahydropyran ring.</p>

Radical Functionalization of Thioglycosides in Aqueous Medium

<p>A visible-light-mediated thiol-ene reaction is successfully operated in aqueous medium. Organic photoredox catalyst (9-mesityl-10-methylacridinum tetrafluoroborate) is used to initiate the radical process to generate thiyl radicals upon light irradiation. Two reaction pathways are discovered in different aqueous buffer system. Thiol-ene adduct is preferred in acidity reaction medium; while disulfide formation is found to be favored in basic reaction medium. Moreover, a visible-light-mediated modified Danishefsky-Wan desulfurization is used to convert thioglycoside to highly substituted tetrahydropyran ring.</p>