scholarly journals Repair of DNA Alkylation Damage by theEscherichia coliAdaptive Response Protein AlkB as Studied by ESI-TOF Mass Spectrometry

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Deyu Li ◽  
James C. Delaney ◽  
Charlotte M. Page ◽  
Alvin S. Chen ◽  
Cintyu Wong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Oxidation ◽  
Dna Alkylation ◽  
Reaction Products ◽  
Ionization Time ◽  
Alkylation Damage ◽  
Living Organisms ◽  
First Time ◽  
Dependent Mechanism

DNA alkylation can cause mutations, epigenetic changes, and even cell death. All living organisms have evolved enzymatic and non-enzymatic strategies for repairing such alkylation damage. AlkB, one of theEscherichia coliadaptive response proteins, uses an α-ketoglutarate/Fe(II)-dependent mechanism that, by chemical oxidation, removes a variety of alkyl lesions from DNA, thus affording protection of the genome against alkylation. In an effort to understand the range of acceptable substrates for AlkB, the enzyme was incubated with chemically synthesized oligonucleotides containing alkyl lesions, and the reaction products were analyzed by electrospray ionization time-of-flight (ESI-TOF) mass spectrometry. Consistent with the literature, but studied comparatively here for the first time, it was found that 1-methyladenine, 1,N6-ethenoadenine, 3-methylcytosine, and 3-ethylcytosine were completely transformed by AlkB, while 1-methylguanine and 3-methylthymine were partially repaired. The repair intermediates (epoxide and possibly glycol) of 3,N4-ethenocytosine are reported for the first time. It is also demonstrated thatO6-methylguanine and 5-methylcytosine are refractory to AlkB, lending support to the hypothesis that AlkB repairs only alkyl lesions attached to the nitrogen atoms of the nucleobase. ESI-TOF mass spectrometry is shown to be a sensitive and efficient tool for probing the comparative substrate specificities of DNA repair proteinsin vitro.

scholarly journals Assessment of Healthy and Harmful Maillard Reaction Products in a Novel Coffee Cascara Beverage: Melanoidins and Acrylamide

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 620 ◽  
Author(s):  
Amaia Iriondo-DeHond ◽  
Ana Sofía Elizondo ◽  
Maite Iriondo-DeHond ◽  
Maria Belén Ríos ◽  
Romina Mufari ◽  
...  
Keyword(s):  
Maillard Reaction ◽  
Antioxidant Properties ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
High Fiber ◽  
Chemical Indicators ◽  
Safety And Health ◽  
Health Promoting ◽  
First Time

Our research aimed to evaluate the formation of Maillard reaction products in sun-dried coffee cascara and their impact on the safety and health promoting properties of a novel beverage called “Instant Cascara” (IC) derived from this coffee by-product. Maillard reaction products in sun-dried coffee cascara have never been reported. “Instant Cascara” (IC) extract was obtained by aqueous extraction and freeze-drying. Proteins, amino acids, lipids, fatty acid profile, sugars, fiber, minerals, and vitamins were analyzed for its nutritional characterization. Acrylamide and caffeine were used as chemical indicators of safety. Colored compounds, also called melanoidins, their stability under 40 °C and in light, and their in vitro antioxidant capacity were also studied. A safe instant beverage with antioxidant properties was obtained to which the following nutritional claims can be assigned: “low fat”, “low sugar” “high fiber” and “source of potassium, magnesium and vitamin C”. For the first time, cascara beverage color was attributed to the presence of antioxidant melanoidins (>10 kDa). IC is a potential sustainable alternative for instant coffee, with low caffeine and acrylamide levels and a healthy composition of nutrients and antioxidants.

scholarly journals DNA Alkylation Damage as a Sensor of Nitrosative Stress in Mycobacterium tuberculosis

2003 ◽  
Vol 71 (2) ◽  
pp. 997-1000 ◽  
Author(s):  
Steven I. Durbach ◽  
Burkhard Springer ◽  
Edith E. Machowski ◽  
Robert J. North ◽  
K. G. Papavinasasundaram ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Nitrosative Stress ◽  
Dna Alkylation ◽  
Genotoxic Effects ◽  
Alkylation Damage ◽  
Damage Repair

ABSTRACT One of the cellular consequences of nitrosative stress is alkylation damage to DNA. To assess whether nitrosative stress is registered on the genome of Mycobacterium tuberculosis, mutants lacking an alkylation damage repair and reversal operon were constructed. Although hypersensitive to the genotoxic effects of N-methyl-N′-nitro-N-nitrosoguanidine in vitro, the mutants displayed no phenotype in vivo, suggesting that permeation of nitrosative stress to the level of cytotoxic DNA damage is restricted.

Comprehensive Study on the chemical profile and anti-tumor activity of secondary metabolites produced by Aspergillus niger

2021 ◽  
Vol 17 ◽  
Author(s):  
Yung-Husan Chen ◽  
Pinghong Chen ◽  
Ching-Hsu Yang ◽  
Xiuna Wu ◽  
Lianzhong Luo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aspergillus Niger ◽  
Inhibitory Effect ◽  
Specific Tumor ◽  
Orbitrap Mass Spectrometry ◽  
Hela S3 ◽  
Diagnostic Ions ◽  
First Time ◽  
Anti Tumor Activity

Objective: Chemical investigation of the extract of sponge-derived fungus, Aspergillus niger, was performed by liquid chromatography coupled with QExactive mass spectrometry for the first time. Method: A total number of 444 constituents were detected, 288 of which were identified positively or tentatively by the comprehensive utilization of accurate molecular weight and fragmentation information acquired from quadrupole orbitrap mass spectrometry. The identified compounds were divided into several types, namely, organic acid, alkaloid, saccharide, amino acid and cyclopeptide, terpenoid, polyketone, phenylpropanoid and other types of compounds. Systematic diagnostic ions and featured fragment patterns were summarized for each type, based on which 8 novel compounds belonging to the same type were characterized. Results: This work provided a rapid approach for the research of microconstituents in a complex analyte. Furthermore, the anti-tumor activity of the extract was evaluated on two different cell lines—Bel-7402 and Hela-S3 in vitro. The tumor-inhibitory effect of the Aspergillus niger extract was confirmed, and may be mainly derived from its pro-apoptotic action. Moreover, the extract exerted more significant cytotoxicity in Bel-7402 cells than Hela-S3 cells, indicative of its selectivity on specific tumor cells. Conclusion: The evidence suggested that the Aspergillus niger extract may potentially serve as a remedy for prevention and therapy of hepatic and breast carcinoma.

Identification of benzisoquinolinone derivatives with cytotoxicities from the leaves of Portulaca oleracea

2019 ◽  
Vol 74 (5-6) ◽  
pp. 139-144
Author(s):  
Rong-Rui Wei ◽  
Qin-Ge Ma ◽  
Guo-Yue Zhong ◽  
Ming Yang ◽  
Zhi-Pei Sang
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
A549 Cell ◽  
Positive Control ◽  
Portulaca Oleracea ◽  
Spectroscopic Methods ◽  
First Time ◽  
Mcf 7

Abstract Three new benzisoquinolinones (1–3), together with seven known benzisoquinolinone derivatives (4–10), were isolated from Portulaca oleracea for the first time. The structures of the isolated compounds (1–10) had been elucidated on the basis of extensive spectroscopic methods including ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance techniques and by comparison with data reported in the references. All isolated compounds were assayed for cytotoxicities against selected human lines in vitro by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Compounds 1, 2, 4, and 7 showed important cytotoxicities against HCT116, MCF-7, U87, and A549 cell lines with IC50 values in the range of 11.62–84.45 μM, which compared with positive control doxorubicin.

scholarly journals Multi-nucleon transfer reactions at ion catcher facilities - a new way to produce and study heavy neutron-rich nuclei

2020 ◽  
Vol 1668 (1) ◽  
pp. 012012
Author(s):  
T. Dickel ◽  
A. Kankainen ◽  
A. Spătaru ◽  
D. Amanbayev ◽  
O. Beliuskina ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Precision ◽  
Transfer Reactions ◽  
Precision Measurements ◽  
Reaction Products ◽  
Nucleon Transfer ◽  
Fission Fragments ◽  
First Results ◽  
First Time ◽  
Experimental Challenge

Abstract The production of very neutron-rich nuclides heavier than fission fragments is an ongoing experimental challenge. Multi-nucleon transfer reactions (MNT) have been suggested as a method to produce these nuclides. By thermalizing the reaction products in gas-filled stopping cells, we can deliver them as cooled high-quality beams to decay, laser and mass spectrometry experiments. High precision mass spectrometry will allow for the first time to universally and unambiguously identify the atomic and proton numbers of the ions produced in MNT reactions. In this way their ground and isomeric state properties can be studied in high-precision measurements. In experiments at IGISOL, Finland and at FRS Ion Catcher, Germany, we have done and will perform broadband measurements of the reaction products, with the aim to improve the understanding of the reaction mechanism and to determine the properties of the ground and isomeric states of the produced nuclides. First results and preparations for upcoming experiments are presented.

Hollow NiAl(OH)x Nanocapsules to Enable Effective Glucose Oxidase Delivery and Synergistic Therapy

2020 ◽  
Vol 16 (5) ◽  
pp. 640-651
Author(s):  
Bin Liu ◽  
Qiang Chu ◽  
Linhua Liao ◽  
Yongjun Wu ◽  
Lucy Di Silvio ◽  
...  
Keyword(s):  
Glucose Oxidase ◽  
Tumor Therapy ◽  
Reaction Products ◽  
Tumor Treatment ◽  
Intrinsic Degradation ◽  
Degradation Properties ◽  
First Time ◽  
Intracellular Glucose

Cellular starvation induced by glucose oxidase (GOx) had been extensively explored as a potential approach for tumor therapy. However, the therapeutic efficacy suffers daunting challenges due to the unsatisfactory intracellular transportation of GOx molecules. Herein for the first time, hydroxide nanoparticles with unique hollow microstructure (denoted as H-NiAl(OH)x) were designed and synthesized for GOx delivery. In this system, despite its intrinsic degradation properties in acidic tumor microenvironment, Ni2+ ions released during degradation may catalyze a Fenton reaction to induce considerable production of cytotoxic hydroxyl radicals (OH). The cavity of hollow nanocapsules provides large surface area, and favors GOx capsulation and delivery. The findings indicate the intracellular glucose can be effectively consumed by GOx transported, and the reaction products consisting of acid and H2O2 facilitate the OH induction of nanocapsules in a synergistic manner. Both in vitro and in vivo antitumor properties have been consequently achieved by H-NiAl(OH)x/GOx systems. This study offering catalytic nanocapsules based on Ni2+ ions may spark a series of follow-on explorations in constructing drug delivery and therapeutic systems for synergistic tumor treatment.

scholarly journals Slx4 becomes phosphorylated after DNA damage in a Mec1/Tel1-dependent manner and is required for repair of DNA alkylation damage

2005 ◽  
Vol 391 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Sonja Flott ◽  
John Rouse
Keyword(s):  
Cell Cycle ◽  
Genome Stability ◽  
Dna Alkylation ◽  
Cell Cycle Checkpoints ◽  
Dependent Manner ◽  
Alkylation Damage ◽  
Dna Helicases ◽  
Wide Range ◽  
In Cells

Members of the RecQ family of DNA helicases, mutated in several syndromes associated with cancer predisposition, are key regulators of genome stability. The Saccharomyces cerevisiae SLX4 gene is required for cell viability in the absence of Sgs1, the only yeast RecQ helicase. SLX4 encodes one subunit of the heterodimeric Slx1–Slx4 endonuclease, although its cellular function is not clear. Slx1–Slx4 was reported to preferentially cleave replication fork-like structures in vitro, and cells lacking SLX4 are hypersensitive to DNA alkylation damage. Here we report that Slx4 becomes phosphorylated in cells exposed to a wide range of genotoxins. Even though it has been proposed that the role of Slx4 is restricted to S-phase, Slx4 phosphorylation is observed in cells arrested in G1 or G2 phases of the cell cycle, but not during an unperturbed cell cycle. Slx4 phosphorylation is completely abolished in cells lacking the Mec1 and Tel1 protein kinases, critical regulators of genome stability, but is barely affected in the absence of both Rad53 and Chk1 kinases. Finally we show that, whereas both Slx1 and Slx4 are dispensable for activation of cell-cycle checkpoints, Slx4, but not Slx1, is required for repair of DNA alkylation damage in both aynchronously growing cells and in G2-phase-arrested cells. These results reveal Slx4 as a new target of the Mec1/Tel1 kinases, with a crucial role in DNA repair that is not restricted to the processing of stalled replisomes.

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