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Chemical & Pharmaceutical Bulletin Sep 2010In continuing our program aimed to search for potent drugs for bacterial infections, a series of 3-(4-halophenyl)-3-oxopropanal and their derivatives were designed,...
In continuing our program aimed to search for potent drugs for bacterial infections, a series of 3-(4-halophenyl)-3-oxopropanal and their derivatives were designed, synthesized and their antibacterial activities in vitro against both Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa were evaluated. Compounds 7, 8, 13-16, 21 and 22 had moderate antibacterial activities against Staphylococcus aureus (minimal inhibitory concentration (MIC) <16 microg/ml), suggesting that the introduction of mono-methoxyamine or ethoxyamine moiety might play an important role in determining the potent antibacterial activities. Furthermore, the antibacterial activities of select compounds 7, 15 and 16 against the clinically important pathogenic bacteria-methicillin-resistant Staphylococcus aureus (MRSA) were also investigated. Results showed that these compounds exhibited more potent activities than the well-known antibacterial agents Houttuynin and Levofloxacin.
Topics: Anti-Bacterial Agents; Bacteria; Escherichia coli; Escherichia coli Infections; Humans; Methicillin-Resistant Staphylococcus aureus; Pseudomonas Infections; Pseudomonas aeruginosa; Pyruvaldehyde; Staphylococcal Infections; Staphylococcus aureus; Structure-Activity Relationship
PubMed: 20823588
DOI: 10.1248/cpb.58.1127 -
Nucleosides, Nucleotides & Nucleic Acids 2006Alkoxyamines react with the open-chain aldehyde form of AP-sites in DNA to produce open-chain aldehyde oximes. Here we characterize the effect of AP-site cleavage by...
Alkoxyamines react with the open-chain aldehyde form of AP-sites in DNA to produce open-chain aldehyde oximes. Here we characterize the effect of AP-site cleavage by yeast AP-endonuclease 1 (APN1) or T4 pyrimidine dimer DNA glycosylase/AP-lyase (T4 Pdg) on the efficiency and stability of the alkoxyamine aldehyde reactive probe (ARP) condensation reaction with AP-sites. The results indicate that (1) reaction of ARP with the open-chain aldehyde equilibrium form of the AP-site was less efficient than with the 3'-alpha,beta-unsaturated aldehyde produced by T4 Pdg; (2) the dRP moiety was least reactive with ARP; (3) both the AP-site and 3'-alpha,beta-unsaturated aldehyde were stable with regard to reaction with ARP over a 30-min incubation period at 37 degrees C; and (4) ARP adducted to the open-chain aldehyde form of the AP-site could be replaced by methoxyamine, but the 3'-alpha,beta-unsaturated aldehyde ARP oxime was stable against methoxyamine attack.
Topics: Aldehydes; Binding Sites; DNA; DNA Adducts; DNA Damage; DNA-(Apurinic or Apyrimidinic Site) Lyase; Deoxyribonuclease IV (Phage T4-Induced); Enzyme Stability; Molecular Probes
PubMed: 16898421
DOI: 10.1080/15257770600726133 -
Journal of the American Chemical Society Oct 2012The direct amination of alkyl and aryl pinacol boronates is accomplished with lithiated methoxyamine. This reaction directly provides aliphatic and aromatic amines,...
The direct amination of alkyl and aryl pinacol boronates is accomplished with lithiated methoxyamine. This reaction directly provides aliphatic and aromatic amines, stereospecifically, and without preactivation of the boronate substrate.
Topics: Alkanes; Amination; Amines; Boron Compounds; Hydrocarbons, Aromatic; Stereoisomerism
PubMed: 23002712
DOI: 10.1021/ja305448w -
The Journal of Biological Chemistry May 1997Entry of monocytes into the vessel wall is an important event in atherogenesis. Previous studies from our laboratory suggest that oxidized arachidonic acid-containing...
Structural identification by mass spectrometry of oxidized phospholipids in minimally oxidized low density lipoprotein that induce monocyte/endothelial interactions and evidence for their presence in vivo.
Entry of monocytes into the vessel wall is an important event in atherogenesis. Previous studies from our laboratory suggest that oxidized arachidonic acid-containing phospholipids present in mildly oxidized low density lipoproteins (MM-LDL) can activate endothelial cells to bind monocytes. In this study, biologically active oxidized arachidonic acid-containing phospholipids were produced by autoxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (Ox-PAPC) and analyzed by liquid chromatography and electrospray ionization mass spectrometry in conjuction with biochemical derivatization techniques. We have now determined the molecular structure of two of three molecules present in MM-LDL and Ox-PAPC that induce monocyte-endothelial interactions. These lipids were identified as 1-palmitoyl-2-(5-oxovaleryl)-sn-glycero-3-phosphocholine (m/z 594.3) and 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphocholine (m/z 610.2). These two molecules were produced by unambiguous total synthesis and found to be identical by analytical techniques and bioactivity assays to those present in MM-LDL and Ox-PAPC. Evidence for the importance of all three oxidized phospholipids in vivo was suggested by their presence in fatty streak lesions from cholesterol-fed rabbits and by their immunoreactivity with natural antibodies present in ApoE null mice. Overall, these studies suggest that specific oxidized derivatives of arachidonic acid-containing phospholipids may be important initiators of atherogenesis.
Topics: Animals; Antibodies, Monoclonal; Arteriosclerosis; Borohydrides; Cell Adhesion; Chromatography, High Pressure Liquid; Endothelium, Vascular; Fluorobenzenes; Hydroxylamines; Lipoproteins, LDL; Mass Spectrometry; Mice; Monocytes; Oxidation-Reduction; Phospholipid Ethers; Phospholipids; Rabbits
PubMed: 9153208
DOI: 10.1074/jbc.272.21.13597 -
The Journal of Biological Chemistry Jul 1976The ultraviolet spectrum of a protein activator of cyclic nucleotide phosphodiesterase and adenylate cyclase purified to homogeneity from bovine brain displayed...
The ultraviolet spectrum of a protein activator of cyclic nucleotide phosphodiesterase and adenylate cyclase purified to homogeneity from bovine brain displayed absorption peaks at 252, 259, 265, 269, and 277 nm. The activator contained no phosphate and did not serve as a substrate for cyclic adenosine 3':5'-monophosphate- or cyclic guanosine 3':5'-monophosphate-dependent protein kinases. The activator binds Ca2+, and the active form appears to be a Ca2+ activator complex (Lin, Y.M., Liu, Y.P., and Cheung, W.Y. (1974) J. Biol. Chem. 249, 4943-4954). Optical rotatory dispersion measurement showed that the Ca2+-free activator exhibited a reduced mean residue rotation ([m']231) of -5700, corresponding to 39% of helical content. In the presence of Ca2+, the [m']231 was increased to -7500, corresponding to 57% of helical content. The Ca2+ -induced conformational change was corroborated by a chemical method. In the presence of Ca2+, the activator was more resistant to trypsin inactivation, presumably because proteins with more helical structures are more resistant to tryptic attack. The activator is rich in aspartate and glutamate. Chemical block of some of the carboxyl groups with glycine ethyl ester or methoxyamine diminished the [m']231 of the activator and its activity, suggesting that blockade of some of the carboxyl groups in the activator unfolded the molecule, leading to a loss of activity. We conclude that Ca2+, which confers more helical structure to the activator, converts the inactive, less helical structure to the active, more helical structure, and that chemical modification of the activator leading to unfolding of the molecule abolishes its biological activity.
Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Animals; Brain; Calcium; Cattle; Cyclic AMP; Cyclic GMP; Egtazic Acid; Enzyme Activation; Kinetics; Nerve Tissue Proteins; Optical Rotatory Dispersion; Phosphoric Diester Hydrolases; Protein Binding; Protein Conformation; Protein Kinases; Spectrophotometry, Ultraviolet
PubMed: 180019
DOI: No ID Found -
Chemical Research in Toxicology Nov 2013The efficacy of DNA-damaging anticancer drugs is highly influenced by cellular DNA repair capacity, and by inhibiting the relevant DNA repair pathway, efficacy of...
The efficacy of DNA-damaging anticancer drugs is highly influenced by cellular DNA repair capacity, and by inhibiting the relevant DNA repair pathway, efficacy of alkylating agents may be increased. Therefore, combining DNA repair inhibitors with anticancer agents that selectively target tumor tissue should improve cancer treatment. The objective of this study was to test the hypothesis that cotreatment of cancer cells with acylfulvene (AF, alkylating agent) and UCN-01 (DNA repair inhibitor) would improve drug efficacy and promote the persistence of DNA adducts. Previous data regarding the relative susceptibility of repair proficient versus deficient cells toward an AF analogue suggests that corresponding adducts are repaired by nuclear excision repair (NER), a cellular process that has been shown to be prevented with UCN-01. In this study, cells were cotreated with nontoxic levels of UCN-01 together with increasing doses of AF. The efficacy of AF was assessed by measuring cytotoxicity and DNA adducts. In addition, cells were cotreated with nontoxic levels of methoxyamine, a known base excision repair (BER) inhibitor, to determine if inhibiting BER also promotes cytotoxicity of AF. DNA-adducts were measured in a sensitive and precise manner by using stable isotope-labeled mass spectrometry analysis. The data obtained in this study demonstrate for the first time that pharmacological inhibition of the NER pathway of DNA repair leads to the persistence of AF-specific adducts and promotes AF cytotoxicity.
Topics: Antineoplastic Agents, Alkylating; Cell Survival; Chromatography, High Pressure Liquid; Colonic Neoplasms; DNA Adducts; DNA Repair; DNA Repair Enzymes; Drug Synergism; HT29 Cells; Humans; Sesquiterpenes; Spectrometry, Mass, Electrospray Ionization; Spiro Compounds; Staurosporine
PubMed: 24099590
DOI: 10.1021/tx400255f -
Bioorganic & Medicinal Chemistry Jul 2012The natural product leinamycin has been found to produce abasic sites in duplex DNA through the hydrolysis of the glycosidic bond of guanine residues modified by this...
The natural product leinamycin has been found to produce abasic sites in duplex DNA through the hydrolysis of the glycosidic bond of guanine residues modified by this drug. In the present study, using a synthetic oligonucleotide duplex, we demonstrate spontaneous DNA strand cleavage at leinamycin-induced abasic sites through a β-elimination reaction. However, methoxyamine modification of leinamycin-induced abasic sites was found to be refractory to the spontaneous β-elimination reaction. Furthermore, this complex was even resistant to the δ-elimination reaction with hot piperidine treatment. Bleomycin and methyl methanesulfonate also induced strand cleavage in a synthetic oligonucleotide duplex even without thermal treatment. However, methoxyamine has a negligible effect on DNA strand cleavage induced by both drugs, suggesting that the mechanism of DNA cleavage induced by leinamycin might be different from those induced by bleomycin or methyl methanesulfonate. In this study, we also assessed the cytotoxicity of leinamycin against a collection of mammalian cell lines defective in various repair pathways. The mammalian cell line defective in the nucleotide excision repair (NER) or base excision repair (BER) pathways was about 3 to 5 times more sensitive to leinamycin as compared to the parental cell line. In contrast, the radiosensitive mutant xrs-5 cell line deficient in V(D)J recombination showed similar sensitivity towards leinamycin compared to the parental cell line. Collectively, our findings suggest that both NER and BER pathways play an important role in the repair of DNA damage caused by leinamycin.
Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; Cell Survival; Cricetinae; DNA; DNA Cleavage; DNA Repair; Hydroxylamines; Lactams; Macrolides; Thiazoles; Thiones
PubMed: 22682923
DOI: 10.1016/j.bmc.2012.05.033 -
Applied Microbiology Apr 1971The prophage-inducing capability of hydroxylamine sulfate and 36 of its derivatives, and of hydrazine dihydrochloride and dihydrazine sulfate and 43 of their...
The prophage-inducing capability of hydroxylamine sulfate and 36 of its derivatives, and of hydrazine dihydrochloride and dihydrazine sulfate and 43 of their derivatives, was determined in Escherichia coli W1709 (lambda). Maximal nontoxic concentrations up to 1 mg/ml were tested. Hydroxylamine sulfate was active at 2.5 mug/ml and the following 17 derivatives were active at concentrations ranging up to 500 mug/ml: alpha-naphthylhydroxylamine, N-hydroxy-2-aminofluorene, oxamyl hydroxamic acid, O-carbamoyl hydroxylamine (isohydroxyurea), N-hydroxyurethane, N-methylhydroxylamine HCl, salicylhydroxamic acid, oxalohydroxamic acid, methoxyamine HCl, ethoxyamine HCl, N, N-diethylhydroxylamine oxalate, formaldoxime, formamidoxime, acetohydroxamic acid, acetaldoxime, acetone oxime, and hydroxyguanidine sulfate. Hydrazine dihydrochloride and dihydrazine sulfate were effective inducers at 5.0 and 2.5 mug/ml, respectively, and the following nine derivatives of them were active at concentrations ranging up to 500 mug/ml: phthalic acid hydrazide, phenylhydrazine HCl, p-nitrophenylhydrazine, p-chlorophenylhydrazine HCl, formylhydrazine, carbohydrazide, semicarbazide HCl, 1-methyl-1-phenyl-hydrazine sulfate, and acetic acid hydrazide. Nineteen hydroxylamine and 34 hydrazine derivatives were ineffective as inducers. Application of the prophage-induction system as a tool for detection of responsive hydroxylamino and hydrazino compounds which may be potential toxicological hazards in the environment is discussed.
Topics: Coliphages; Escherichia coli; Hydrazines; Hydrochloric Acid; Hydroxylamines; Lysogeny; Sulfates
PubMed: 4930282
DOI: 10.1128/am.21.4.726-731.1971 -
The Journal of Neuroscience : the... Oct 2006Cultured neurons exposed to synthetic beta-amyloid (Abeta) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA... (Comparative Study)
Comparative Study
Cultured neurons exposed to synthetic beta-amyloid (Abeta) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-beta (DNA pol-beta) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments on cross-linked nucleoprotein fragments from Abeta-treated neurons, we demonstrate that DNA pol-beta coimmunoprecipitates with cell division cycle 45 (Cdc45) and with DNA primase in short nucleoprotein fragments. This indicates that DNA pol-beta is loaded into neuronal DNA replication forks after Abeta treatment. In response to Abeta the canonical DNA-synthesizing enzyme DNA pol-delta also was loaded into neuronal replication forks, but at later times than DNA pol-beta. Methoxyamine, an inhibitor of the apurinic/apyrimidinic endonuclease that allows for the recruitment of DNA pol-beta during the process of base excision repair (BER), failed to affect coimmunoprecipitation between DNA pol-beta and Cdc45, indicating that DNA pol-beta loading to the replication forks is independent of DNA breaks. However, methoxyamine reduced DNA replication and ensuing apoptosis in neurons exposed to Abeta, suggesting that an efficient BER process allows DNA replication to proceed up to the threshold for death. These data demonstrate that DNA pol-beta is an essential component of the DNA replication machinery in Abeta-treated neurons and additionally support the hypothesis of a close association of cell cycle events with neuronal death in Alzheimer's disease (AD). Accordingly, by investigating the neuronal expression of DNA pol-beta, along with phosphorylated retinoblastoma protein and neurofibrillary changes in AD brain, we show an early involvement of DNA pol-beta in the pathogenesis of AD.
Topics: Adult; Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Brain; Cells, Cultured; DNA Polymerase beta; DNA Replication; Female; Gene Expression Regulation, Enzymologic; Humans; Male; Middle Aged; Neurons; Retinoblastoma Protein
PubMed: 17065437
DOI: 10.1523/JNEUROSCI.2793-06.2006 -
DNA Repair Nov 2009Oxidative DNA damage has been implicated in a number of central nervous system pathologies. The base excision repair (BER) pathway is one of the most important cellular...
Oxidative DNA damage has been implicated in a number of central nervous system pathologies. The base excision repair (BER) pathway is one of the most important cellular protection mechanisms that respond to oxidative DNA damage. Human apurinic (apyrimidinic) endonuclease/redox effector factor (APE1/Ref-1 or APE1) is an essential enzyme in the BER pathway and is expressed in both mitotic and post-mitotic cells in humans. In neurons, a reduction of APE1 expression increases chemotherapy-induced cytotoxicity, while overexpression of APE1 protects cells against the cytotoxicity. However, given the multiple functions of APE1, knockdown of total APE1 is not completely informative of whether it is the redox or DNA repair activity, or interactions with other proteins. Therefore, the use of selective small molecules that can block each function independent of the other is of great benefit in ascertaining APE1 function in post-mitotic cells. In this study, we chose differentiated SH-SY5Y cells as our post-mitotic cell line model to investigate whether a drug-induced decrease in APE1 DNA repair or redox activity contributes to the growth and survival of post-mitotic cells under oxidative DNA damaging conditions. Here, we demonstrate that overexpression of WT-APE1 or C65-APE1 (repair competent) results in significant increase in cell viability after exposure to H(2)O(2). However, the 177/226-APE1 (repair deficient) did not show a protective effect. This phenomenon was further confirmed by the use of methoxyamine (MX), which blocks the repair activity of APE1 that results in enhanced cell killing and apoptosis in differentiated SH-SY5Y cells and in neuronal cultures after oxidative DNA damaging treatments. Blocking APE1 redox function by a small molecule inhibitor, BQP did not decrease viability of SH-SY5Y cells or neuronal cultures following oxidative DNA damaging treatments. Our results demonstrate that the DNA repair function of APE1 contributes to the survival of nondividing post-mitotic cells following oxidative DNA damage.
Topics: Cell Differentiation; Cell Line, Tumor; Cell Survival; DNA Damage; DNA Repair; DNA-(Apurinic or Apyrimidinic Site) Lyase; Humans; Hydrogen Peroxide; Hydroxylamines; Neuroblastoma; Oxidative Stress
PubMed: 19726241
DOI: 10.1016/j.dnarep.2009.08.003