scholarly journals Optimizing the Reaction Conditions for the Formation of Fumarate via Trans-Hydrogenation

2021 ◽  
Author(s):  
Laura Wienands ◽  
Franziska Theiß ◽  
James Eills ◽  
Lorenz Rösler ◽  
Stephan Knecht ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Thermal Equilibrium ◽  
Reaction Rate ◽  
Low Cost ◽  
Hydrogen Gas ◽  
Metabolic Imaging ◽  
Reaction Conditions ◽  
Precursor Molecule ◽  
Solution Preparation

AbstractParahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This method has allowed for biomolecules to be hyperpolarized to such a level that they can be used for real time in vivo metabolic imaging. One particularly promising example is fumarate, which can be rapidly and efficiently hyperpolarized at low cost by hydrogenating an acetylene dicarboxylate precursor molecule using parahydrogen. The reaction is relatively slow compared to the timescale on which the hyperpolarization relaxes back to thermal equilibrium, and an undesirable 2nd hydrogenation step can convert the fumarate into succinate. To date, the hydrogenation chemistry has not been thoroughly investigated, so previous work has been inconsistent in the chosen reaction conditions in the search for ever-higher reaction rate and yield. In this work we investigate the solution preparation protocols and the reaction conditions on the rate and yield of fumarate formation. We report conditions to reproducibly yield over 100 mM fumarate on a short timescale, and discuss aspects of the protocol that hinder the formation of fumarate or lead to irreproducible results. We also provide experimental procedures and recommendations for performing reproducible kinetics experiments in which hydrogen gas is repeatedly bubbled into an aqueous solution, overcoming challenges related to the viscosity and surface tension of the water.

scholarly journals Rapid hyperpolarization and purification of the metabolite fumarate in aqueous solution

2021 ◽  
Vol 118 (13) ◽  
pp. e2025383118
Author(s):  
Stephan Knecht ◽  
John W. Blanchard ◽  
Danila Barskiy ◽  
Eleonora Cavallari ◽  
Laurynas Dagys ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Nuclear Polarization ◽  
State Of The Art ◽  
Signal Strength ◽  
Acid Precipitation ◽  
Metabolic Imaging ◽  
Reaction Conditions ◽  
Current State ◽  
Aqueous Solvent

Hyperpolarized fumarate is a promising biosensor for carbon-13 magnetic resonance metabolic imaging. Such molecular imaging applications require nuclear hyperpolarization to attain sufficient signal strength. Dissolution dynamic nuclear polarization is the current state-of-the-art methodology for hyperpolarizing fumarate, but this is expensive and relatively slow. Alternatively, this important biomolecule can be hyperpolarized in a cheap and convenient manner using parahydrogen-induced polarization. However, this process requires a chemical reaction, and the resulting solutions are contaminated with the catalyst, unreacted reagents, and reaction side-product molecules, and are hence unsuitable for use in vivo. In this work we show that the hyperpolarized fumarate can be purified from these contaminants by acid precipitation as a pure solid, and later redissolved to a desired concentration in a clean aqueous solvent. Significant advances in the reaction conditions and reactor equipment allow for formation of hyperpolarized fumarate at 13C polarization levels of 30–45%.

scholarly journals Rapid Hyperpolarization and Purification of the Metabolite Fumarate in Aqueous Solution

2020 ◽  
Author(s):  
Stephan Knecht ◽  
John W. Blanchard ◽  
Danila Barskiy ◽  
Eleonora Cavallari ◽  
Laurynas Dagys ◽  
...  
Keyword(s):  
Nuclear Polarization ◽  
State Of The Art ◽  
Acid Precipitation ◽  
Metabolic Imaging ◽  
Reaction Conditions ◽  
Current State ◽  
Promising Agent ◽  
Aqueous Solvent ◽  
Cellular Necrosis

Hyperpolarized fumarate is a promising agent for carbon-13 magnetic resonance metabolic imaging of cellular necrosis. Molecular imaging applications require nuclear hyperpolarization to attain sufficient signal strength. Dissolution dynamic nuclear polarization is the current state-of-the-art methodology for hyperpolarizing fumarate, but this is expensive and relatively slow. Alternatively, this important biomolecule can be hyperpolarized in a cheap and convenient manner using parahydrogen-induced polarization. However, this process requires a chemical reaction, and the resulting hyperpolarized fumarate solutions are contaminated with the catalyst, unreacted reagents, and reaction side product molecules, and are hence unsuitable for use <i>in vivo</i>. In this work we show that the hyperpolarized fumarate can be purified from these contaminants by acid precipitation as a pure solid, and later redissolved at a chosen concentration in a clean aqueous solvent. Significant advances in the reaction conditions and reactor equipment allow us to form hyperpolarized fumarate at a concentration of several hundred millimolar, at <sup>13</sup>C polarization levels of 30-45%.

scholarly journals Rapid Hyperpolarization and Purification of the Metabolite Fumarate in Aqueous Solution

2020 ◽  
Author(s):  
Stephan Knecht ◽  
John W. Blanchard ◽  
Danila Barskiy ◽  
Eleonora Cavallari ◽  
Laurynas Dagys ◽  
...  
Keyword(s):  
Nuclear Polarization ◽  
State Of The Art ◽  
Acid Precipitation ◽  
Metabolic Imaging ◽  
Reaction Conditions ◽  
Current State ◽  
Promising Agent ◽  
Aqueous Solvent ◽  
Cellular Necrosis

Hyperpolarized fumarate is a promising agent for carbon-13 magnetic resonance metabolic imaging of cellular necrosis. Molecular imaging applications require nuclear hyperpolarization to attain sufficient signal strength. Dissolution dynamic nuclear polarization is the current state-of-the-art methodology for hyperpolarizing fumarate, but this is expensive and relatively slow. Alternatively, this important biomolecule can be hyperpolarized in a cheap and convenient manner using parahydrogen-induced polarization. However, this process requires a chemical reaction, and the resulting hyperpolarized fumarate solutions are contaminated with the catalyst, unreacted reagents, and reaction side product molecules, and are hence unsuitable for use <i>in vivo</i>. In this work we show that the hyperpolarized fumarate can be purified from these contaminants by acid precipitation as a pure solid, and later redissolved at a chosen concentration in a clean aqueous solvent. Significant advances in the reaction conditions and reactor equipment allow us to form hyperpolarized fumarate at a concentration of several hundred millimolar, at <sup>13</sup>C polarization levels of 30-45%.

scholarly journals Development of a Quick Quantitative Real-Time PCR for the In Vivo Detection and Quantification of Peach latent mosaic viroid

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Olivier Parisi ◽  
Philippe Lepoivre ◽  
M. Haissam Jijakli
Keyword(s):  
Real Time ◽  
Plant Pathogens ◽  
Low Cost ◽  
Extraction Procedure ◽  
Reaction Conditions ◽  
Routine Testing ◽  
In Vivo Detection ◽  
Peach Trees

Viroids are plant pathogens infecting a broad range of herbaceous and tree crops. Among them, the Peach latent mosaic viroid (PLMVd) infects mainly peach trees, causing a loss of production with no curative options. Detecting this viroid is thus important for certification procedures aiming to avoid the release of infected material into orchards. Presented here is a complete detection method based on reverse transcription (RT) followed by a quantitative real-time polymerase chain reaction (PCR). New primers were selected and optimal reaction conditions determined for routine application of the method. The technique is 105 times more sensitive than the endpoint RT-PCR used for PLMVd detection, and permits earlier detection of PLMVd in infected plants. The quick, low-cost extraction procedure used and the quality of the results obtained make this method suitable for routine testing.

A technique for protecting delicate specimens during processing

1989 ◽  
Vol 47 ◽  
pp. 982-983
Author(s):  
R.J. Mount ◽  
R.V. Harrison
Keyword(s):  
Basilar Membrane ◽  
Low Cost ◽  
Organ Of Corti ◽  
Region Of Interest ◽  
Sensory Epithelium ◽  
Physical Damage ◽  
Air Drying ◽  
Specimen Handling ◽  
Two Component

The sensory end organ of the ear, the organ of Corti, rests on a thin basilar membrane which lies between the bone of the central modiolus and the bony wall of the cochlea. In vivo, the organ of Corti is protected by the bony wall which totally surrounds it. In order to examine the sensory epithelium by scanning electron microscopy it is necessary to dissect away the protective bone and expose the region of interest (Fig. 1). This leaves the fragile organ of Corti susceptible to physical damage during subsequent handling. In our laboratory cochlear specimens, after dissection, are routinely prepared by the O-T- O-T-O technique, critical point dried and then lightly sputter coated with gold. This processing involves considerable specimen handling including several hours on a rotator during which the organ of Corti is at risk of being physically damaged. The following procedure uses low cost, readily available materials to hold the specimen during processing ,preventing physical damage while allowing an unhindered exchange of fluids.Following fixation, the cochlea is dehydrated to 70% ethanol then dissected under ethanol to prevent air drying. The holder is prepared by punching a hole in the flexible snap cap of a Wheaton vial with a paper hole punch. A small amount of two component epoxy putty is well mixed then pushed through the hole in the cap. The putty on the inner cap is formed into a “cup” to hold the specimen (Fig. 2), the putty on the outside is smoothed into a “button” to give good attachment even when the cap is flexed during handling (Fig. 3). The cap is submerged in the 70% ethanol, the bone at the base of the cochlea is seated into the cup and the sides of the cup squeezed with forceps to grip it (Fig.4). Several types of epoxy putty have been tried, most are either soluble in ethanol to some degree or do not set in ethanol. The only putty we find successful is “DUROtm MASTERMENDtm Epoxy Extra Strength Ribbon” (Loctite Corp., Cleveland, Ohio), this is a blue and yellow ribbon which is kneaded to form a green putty, it is available at many hardware stores.

Studying dispersed and rheological properties of hydrocarbon-containing acid emulsions and their efficiency in removing asphalt-resin-paraffin deposits

2020 ◽  
pp. 128-139
Author(s):  
M. Yu. Shumakher ◽  
V. V. Konovalov ◽  
A. P. Melnikov
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Rheological Properties ◽  
Reaction Rate ◽  
Experimental Studies ◽  
Efficient Removal ◽  
Reservoir Properties ◽  
Hydrocarbon Solvents ◽  
Formation Zone ◽  
Effect Of The Composition

Currently, the treatment of the bottomhole formation zone with acidic compositions is one of the most common methods to intensify the oil inflow. The use of various modified acid compositions increases the efficiency of acid treatments on the bottomhole formation zone. Acid compositions, including those containing hydrocarbon solvents, which contribute to more efficient removal of organic colmatants, affect the reaction rate of the reagent with the rock and processing equipment, change the reservoir properties, etc.The article presents the results of experimental studies, which are aimed at establishing the effect of the composition of hydrocarbon-containing acidic emulsions consisting of an aqueous solution of hydrochloric acid, toluene and Neonol AF 9-10 on their dispersed and rheological properties, as well as their efficiency in removing paraffin deposits.

Microbial Bioconversion: A Regio-specific Method for Novel Drug Design and Toxicological Study of Metabolites

2019 ◽  
Vol 20 (14) ◽  
pp. 1156-1162
Author(s):  
Maria Yousuf ◽  
Waqas Jamil ◽  
Khayala Mammadova
Keyword(s):  
Microbial Transformation ◽  
Specific Method ◽  
Reaction Conditions ◽  
Small Organic Molecules ◽  
Toxicological Studies ◽  
Drug Designing ◽  
Transformation Methods ◽  
Novel Drug

The methods of chemical structural alteration of small organic molecules by using microbes (fungi, bacteria, yeast, etc.) are gaining tremendous attention to obtain structurally novel and therapeutically potential leads. The regiospecific mild environmental friendly reaction conditions with the ability of novel chemical structural modification in compounds categorize this technique; a distinguished and unique way to obtain medicinally important drugs and their in vivo mimic metabolites with costeffective and timely manner. This review article shortly addresses the immense pharmaceutical importance of microbial transformation methods in drug designing and development as well as the role of CYP450 enzymes in fungi to obtain in vivo drug metabolites for toxicological studies.

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