Permeability of MgCl2- Graphite Reactive Compound

DNA-reactive compounds are harnessed for cancer chemotherapy. Their genotoxic effects are considered to be the main mechanism for the cytotoxicity to date. Because this mechanism preferentially affects actively proliferating cells, it is postulated that the cytotoxicity is specific to cancer cells. Nonetheless, they do harm normal quiescent cells, suggesting that there are other cytotoxic mechanisms to be uncovered. By employing doxorubicin as a representative DNA-reactive compound, we have discovered a cytotoxic mechanism that involves a cellular noncoding RNA (ncRNA) nc886 and protein kinase R (PKR) that is a proapoptotic protein. nc886 is transcribed by RNA polymerase III (Pol III), binds to PKR, and prevents it from aberrant activation in most normal cells. We have shown here that doxorubicin evicts Pol III from DNA and, thereby, shuts down nc886 transcription. Consequently, the instantaneous depletion of nc886 provokes PKR and leads to apoptosis. In a short-pulse treatment of doxorubicin, these events are the main cause of cytotoxicity preceding the DNA damage response in a 3D culture system as well as the monolayer cultures. By identifying nc886 as a molecular signal for PKR to sense doxorubicin, we have provided an explanation for the conundrum why DNA-damaging drugs can be cytotoxic to quiescent cells that have the competent nc886/PKR pathway.

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Untargetted Metabolomic Exploration of the Mycobacterium tuberculosis Stress Response to Cinnamon Essential Oil

Biomolecules ◽

10.3390/biom10030357 ◽

2020 ◽

Vol 10 (3) ◽

pp. 357 ◽

Cited By ~ 2

Author(s):

Elwira Sieniawska ◽

Rafał Sawicki ◽

Joanna Golus ◽

Milen I. Georgiev

Keyword(s):

Stress Response ◽

Essential Oil ◽

Redox Homeostasis ◽

Membrane Integrity ◽

Antimycobacterial Activity ◽

Stress Factors ◽

Stress Response System ◽

Reactive Compound ◽

Cinnamon Essential Oil ◽

Cell Wall Permeability

The antimycobacterial activity of cinnamaldehyde has already been proven for laboratory strains and for clinical isolates. What is more, cinnamaldehyde was shown to threaten the mycobacterial plasma membrane integrity and to activate the stress response system. Following promising applications of metabolomics in drug discovery and development we aimed to explore the mycobacteria response to cinnamaldehyde within cinnamon essential oil treatment by untargeted liquid chromatography–mass spectrometry. The use of predictive metabolite pathway analysis and description of produced lipids enabled the evaluation of the stress symptoms shown by bacteria. This study suggests that bacteria exposed to cinnamaldehyde could reorganize their outer membrane as a physical barrier against stress factors. They probably lowered cell wall permeability and inner membrane fluidity, and possibly redirected carbon flow to store energy in triacylglycerols. Being a reactive compound, cinnamaldehyde may also contribute to disturbances in bacteria redox homeostasis and detoxification mechanisms.

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d-Galacturonic Acid: A Highly Reactive Compound in Nonenzymatic Browning. 2. Formation of Amino-Specific Degradation Products

Journal of Agricultural and Food Chemistry ◽

10.1021/acs.jafc.5b01121 ◽

2015 ◽

Vol 63 (28) ◽

pp. 6457-6465 ◽

Cited By ~ 10

Author(s):

Steffen Wegener ◽

Maria-Anna Bornik ◽

Lothar W. Kroh

Keyword(s):

Galacturonic Acid ◽

Degradation Products ◽

Nonenzymatic Browning ◽

Reactive Compound ◽

Specific Degradation

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Confirmation of d-aspartic acid in the novel dipeptide β-aspartylglycine isolated from tissue extract of Aplysia kurodai

Biochemical Journal ◽

10.1042/bj2630617 ◽

1989 ◽

Vol 263 (2) ◽

pp. 617-620 ◽

Cited By ~ 4

Author(s):

M Sato ◽

T Yamaguchi ◽

N Kanno ◽

Y Sato

Keyword(s):

Aspartic Acid ◽

Body Wall ◽

Optical Resolution ◽

Paper Electrophoresis ◽

Ion Exchange Chromatography ◽

Exchange Chromatography ◽

Optical Rotatory Dispersion ◽

The Novel ◽

Reactive Compound ◽

High Concentrations

A novel o-phthalaldehyde-reactive compound was found in the h.p.l.c. chromatogram of Aplysia kurodai extract. This compound was isolated by ion-exchange chromatography and preparative high-voltage paper electrophoresis. It was shown by optical-rotatory-dispersion spectrum and optical-resolution h.p.l.c. analysis that this compound consisted of equimolar amounts of D-aspartic acid and glycine. This compound resisted cleavage in the Edman reaction. This peptide was inferred to be beta-D-aspartylglycine, and this was confirmed by synthesis. beta-D-Aspartylglycine was detected in all tissues of Aplysia kurodai, with especially high concentrations in body wall (skin and muscle) and gill.

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Diiron N-bridged species bearing phthalocyanine ligand catalyzes oxidation of methane, propane and benzene under mild conditions

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424608000431 ◽

2008 ◽

Vol 12 (10) ◽

pp. 1078-1089 ◽

Cited By ~ 34

Author(s):

Evgeny V. Kudrik ◽

Pavel Afanasiev ◽

Denis Bouchu ◽

Jean-Marc M. Millet ◽

Alexander B. Sorokin

Keyword(s):

Transfer Reaction ◽

Practical Importance ◽

Biologically Relevant ◽

Physiological Conditions ◽

Oxidation Of Methane ◽

Reactive Compound ◽

Aqueous Oxidation ◽

High Valent ◽

Benzene Oxide ◽

Oxidation Of Benzene

Transformation of methane, the most abundant and the least reactive compound of natural gas to valuable products is one of the most difficult chemical problems of great practical importance. In Nature, methane monooxygenase enzymes transform methane to methanol in water under physiological conditions. However, chemical analogs for such a transformation are unknown. Here, we show the mild and efficient aqueous oxidation of methane by hydrogen peroxide, an ecologically and biologically relevant oxidant catalyzed by supported μ-nitrido diiron phthalocyanine dimer, (FePc t Bu 4)2 N . This bio-inspired complex containing a stable Fe – N – Fe motif catalyzes the oxidation of methane to methanol which is further transformed to formaldehyde and formic acid as is demonstrated using 13 CH 4 and 18 O labelling. (FePc t Bu 4)2 N - H 2O2 system shows a high activity in the oxidation of benzene to phenol which occurs via formation of benzene oxide and exhibits NIH shift typically accociated with biological oxidation. Mechanistic features of oxidation of methane and benzene as well as detected intermediate hydroperoxo- and high valent oxo diiron complexes support an O-atom transfer reaction mechanism relevant to bio-oxidation.

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Cytochrome P450-mediated metabolism of N-(2-methoxyphenyl)-hydroxylamine, a human metabolite of the environmental pollutants and carcinogens o-anisidine and o-nitroanisole

Interdisciplinary Toxicology ◽

10.2478/v10102-010-0045-8 ◽

2008 ◽

Vol 1 (3-4) ◽

pp. 218-224 ◽

Cited By ~ 1

Author(s):

Karel Naiman ◽

Helena Dračínská ◽

Martin Dračínský ◽

Markéta Martínková ◽

Václav Martínek ◽

...

Keyword(s):

Cytochrome P450 ◽

Cytochromes P450 ◽

Environmental Pollutants ◽

Human Metabolite ◽

Hepatic Microsomes ◽

Minor Metabolite ◽

Reactive Compound ◽

A Minor

Cytochrome P450-mediated metabolism ofN-(2-methoxyphenyl)-hydroxylamine, a human metabolite of the environmental pollutants and carcinogenso-anisidine ando-nitroanisoleN-(2-methoxyphenyl)hydroxylamine is a human metabolite of the industrial and environmental pollutants and bladder carcinogens 2-methoxyaniline (o-anisidine) and 2-methoxynitrobenzene (o-nitroanisole). Here, we investigated the ability of hepatic microsomes from rat and rabbit to metabolize this reactive compound. We found thatN-(2-methoxyphenyl)hydroxylamine is metabolized by microsomes of both species mainly too-aminophenol and a parent carcinogen,o-anisidine, whereas 2-methoxynitrosobenzene (o-nitrosoanisole) is formed as a minor metabolite. AnotherN-(2-methoxyphenyl)hydroxylamine metabolite, the exact structure of which has not been identified as yet, was generated by hepatic microsomes of rabbits, but its formation by those of rats was negligible. To evaluate the role of rat hepatic microsomal cytochromes P450 (CYP) inN-(2-methoxyphenyl)hydroxylamine metabolism, we investigated the modulation of its metabolism by specific inducers of these enzymes. The results of this study show that rat hepatic CYPs of a 1A subfamily and, to a lesser extent those of a 2B subfamily, catalyzeN-(2-methoxyphenyl)hydroxylamine conversion to form both its reductive metabolite,o-anisidine, ando-aminophenol. CYP2E1 is the most efficient enzyme catalyzing conversion ofN-(2-methoxyphenyl)hydroxylamine too-aminophenol.

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Obtaining and Characterizing Alginate/k-Carrageenan Hydrogel Cross-Linked with Adipic Dihydrazide

Advances in Materials Science and Engineering ◽

10.1155/2013/380716 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Violeta Paşcalău ◽

Violeta Popescu ◽

George L. Popescu ◽

Mircea C. Dudescu ◽

Gheorghe Borodi ◽

...

Keyword(s):

Cross Linking ◽

Sodium Metaperiodate ◽

Second Stage ◽

End Groups ◽

Reactive Compound ◽

The Cross ◽

Chemical Cross Linking

The aim of this paper is obtaining and characterizing hydrogels based on different ratios of oxidized alginate (oA) and k-carrageenan (C), chemically cross-linked with adipic dihydrazide (adh). The alginate (A) was first oxidized with sodium metaperiodate in order to transform it into the dialdehyde derivative, a more reactive compound than alginate. A known procedure for oxidation of alginate with sodium metaperiodate in ethanol-water in order to improve alginate reactivity by transforming the hydroxyl end-groups into dialdehyde was used, preceded by a partially cleavage of the alginate chains. In the second stage, the mixture of dialdehydic derivative of oxidized alginate, k-carrageenan and glycerol subjected to reaction with adipic dihydrazide leads to a Semi-Interpenetrated Network covalently cross-linked alginate/k-carrageenan hydrogel (oACadh), based on the dihydrazone compound which is responsible for the chemical cross-linking. Pure alginate, k-carrageenan, oxidized alginate, adipic dihydrazide and the cross-linked hydrogel were characterized by: FTIR, XRD, and SEM.

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Cysteine 96 of Ntcp is responsible for NO-mediated inhibition of taurocholate uptake

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00089.2013 ◽

2013 ◽

Vol 305 (7) ◽

pp. G513-G519 ◽

Cited By ~ 7

Author(s):

Umadevi Ramasamy ◽

M. Sawkat Anwer ◽

Christopher M. Schonhoff

Keyword(s):

Nitric Oxide ◽

Plasma Membrane ◽

Cysteine Residue ◽

Cysteine Residues ◽

Wild Type ◽

Reactive Compound

The Na+taurocholate (TC) cotransporting polypeptide Ntcp/NTCP mediates TC uptake across the sinusoidal membrane of hepatocytes. Previously, we demonstrated that nitric oxide (NO) inhibits TC uptake through S-nitrosylation of a cysteine residue. Our current aim was to determine which of the eight cysteine residues of Ntcp is responsible for NO-mediated S-nitrosylation and inhibition of TC uptake. Thus, we tested the effect of NO on TC uptake in HuH-7 cells transiently transfected with cysteine-to-alanine mutant Ntcp constructs. Of the eight mutants tested, only C44A Ntcp displayed decreased total and plasma membrane (PM) levels that were also reflected in decreased TC uptake. C266A Ntcp showed a decrease in TC uptake that was not explained by a decrease in total expression or PM localization, indicating that C266 is required for optimal uptake. We speculated that NO would target C266 since a previous report had shown the thiol reactive compound [2-(trimethylammonium) ethyl] methanethiosulfonate bromide (MTSET) inhibits TC uptake by wild-type NTCP but not by C266A NTCP. We confirmed that MTSET targets C266 of Ntcp, but, surprisingly, we found that C266 was not responsible for NO-mediated inhibition of TC uptake. Instead, we found that C96 was targeted by NO since C96A Ntcp was insensitive to NO-mediated inhibition of TC uptake. We also found that wild-type but not C96A Ntcp is S-nitrosylated by NO, suggesting that C96 is important in regulating Ntcp function in response to elevated levels of NO.

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Removal of Dissolved Impurities from Molten Metals

10.1093/oso/9780198811923.003.0004 ◽

2021 ◽

pp. 240-302

Author(s):

Thorvald Abel Engh ◽

Geoffrey K. Sigworth ◽

Anne Kvithyld

Keyword(s):

Mass Transfer ◽

Physical Properties ◽

Fractional Crystallisation ◽

Molten Metals ◽

Transfer Coefficients ◽

Efficient Removal ◽

Volatile Elements ◽

Mass Transfer Coefficients ◽

Contact Areas ◽

Reactive Compound

Impurities are transferred out at the boundary of the liquid. Velocities normal to the boundary are small. Therefore, for efficient removal contact areas and times should be large. Transfer depends on the chemical and physical properties of the liquid and the phase that captures the impurities at the boundary. This phase may be a liquid, gas (vacuum) or solid. Properties can be described in terms of equilibrium and empirical mass transfer coefficients. Vacuum may be applied to remove volatile elements. Refining can be carried out by partial solidification or fractional crystallisation, using the segregation that occurs during freezing of an alloy. Finally, an element can be added to form a reactive compound followed by removal of the compound by sedimentation or filtration.

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Six pyrimidonium salts: determination of their crystal structures and studies of their prototropic behaviour in solution

Canadian Journal of Chemistry ◽

10.1139/v84-195 ◽

1984 ◽

Vol 62 (6) ◽

pp. 1194-1202 ◽

Cited By ~ 7

Author(s):

Thomas W. S. Lee ◽

Steven J. Rettig ◽

Ross Stewart ◽

James Trotter

Keyword(s):

Hydrogen Exchange ◽

Molecular Geometry ◽

High Reactivity ◽

Methyl Groups ◽

Contributing Factors ◽

X Ray ◽

X Ray Crystallography ◽

Reactive Compound ◽

Chloride Salts

Six methyl-substituted 2-pyrimidonium chloride salts have been prepared and the rates of hydrogen exchange of their reactive methyl groups (at the 4- and 6-positions) have been determined in DCl/D2O solution. Adjacent methyl groups, whether on nitrogen or carbon, activate the exchanging centres, whereas more distant methyl groups have a deactivating effect. The molecular geometry of the salts has been determined by X-ray crystallography with the view to determining whether the presence of strain in the pyrimidonium ring can account for the activating effect of adjacent methyl. The most reactive compound, the 1,5,6-trimethylpyrimidonium chloride, has a geometry that is consistent with high reactivity, viz. a non-planar ring and short H … H intermethyl distance. However, the 1,4,5,6-tetramethyl compound, which also is non-planar and has an extremely short 5-6 intermethyl distance (1.99 Å), is not highly reactive; that is, the heightened strain is unable to overcome the deactivating inductive effect of the additional methyl group. We conclude that deviations from ring planarity and short intermethyl distances are insufficient to account for the activation produced by adjacent methyl though they appear to be contributing factors to this effect.

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