La erupción y el tubo volcánico del volcán Corona (Lanzarote, Islas Canarias) (2003)
Carracedo, J. C., Singer, B., Jicha, B., Guillou, H., Rodríguez Badiola, E., Meco, Joaquín, ...
The island of Lanzarote, located at the eastern, oldest age of the Canarian hotspot island-chain, has very sparse Holocene rejuvenation volcanism, possibly restricted to the 1824 and 1730 eruptions,...
The Corona Volcano (Lanzarote) lava tube (2003)
Carracedo, J. C., Láinez, A., Socorro, S., Gimeno, D., Pérez Torrado, F. J., Meco, J., ...
Estudio de la erupción pre-holocena del Volcán Corona, Lanzarote, y explicación del origen del tubo de lava sumergido
M. Khorrami, B. Singer, D. Lockard, Mehdi R. Khorrami, Bart A. Singer, David P. Lockard
Unsteady computational simulations of a multi-element, high-lift configuration are performed. Emphasis is placed on accurate spatio-temporal resolution of the free shear layer in the slat-cove...
Hang, B., Chenna, A., Fraenkel-Conrat, H., Singer, B.
The major human apurinic/apyrimidinic (AP) endonuclease (class II) is known to cleave DNA 5′ adjacent to an AP site, which is probably the most common DNA damage produced hydrolytically or by...
Hang, B., Singer, B., Margison, G. P., Elder, R. H.
It has previously been reported that 1,N6-ethenoadenine (ɛA), deaminated adenine (hypoxanthine, Hx), and 7,8-dihydro-8-oxoguanine (8-oxoG), but not 3,N4-ethenocytosine (ɛC), are released from DNA...
Hang, B., Medina, M., Fraenkel-Conrat, H., Singer, B.
Etheno adducts in DNA arise from multiple endogenous and exogenous sources. Of these adducts we have reported that, 1,N6-ethenoadenine (ɛA) and 3,N4-ethenocytosine (ɛC) are removed from DNA by two...
Chenna, A, Hang, B, Rydberg, B, Kim, E, Pongracz, K, Bodell, W J, ...
Benzene is a ubitiquous human environment mental carcinogen. One of the major metabolites is hydroquinone, which is oxidized in vivo to give p-benzoquinone (p-BQ). Both metabolites are toxic to human...
Evidence from in vitro replication that O6-methylguanine can adopt multiple conformations.
Dosanjh, M K, Loechler, E L, Singer, B
The effect of O6-methylguanine (m6G) on replication, in a partially double-stranded defined 25-base oligonucleotide, has been studied under nonlimiting conditions of unmodified dNTPs and over an...
Singer, B, Antoccia, A, Basu, A K, Dosanjh, M K, Fraenkel-Conrat, H, Gallagher, P E, ...
We previously described a protein, isolated from human tissues and cells, that bound to a defined double-stranded oligonucleotide containing a single site-specifically placed 1,N6-ethenoadenine. It...
Human cells contain protein specifically binding to a single 1,N6-ethenoadenine in a DNA fragment.
Rydberg, B, Dosanjh, M K, Singer, B
A human DNA binding protein has been characterized from cell-free extracts of liver, placenta, and cultured cells. This protein, apparent molecular mass approximately 35 kDa, to our knowledge, does...
Cheng, K C, Preston, B D, Cahill, D S, Dosanjh, M K, Singer, B, Loeb, L A
Vinyl chloride is a known human and rodent carcinogen that forms several cyclic base derivatives in DNA. The mutagenic potential of these derivatives has been examined in vitro but not in vivo. One...
Rothwell, D. G., Hang, B., Gorman, M. A., Freemont, P. S., Singer, B., Hickson, I. D.
HAP1, also known as APE/Ref-1, is the major apurinic/apyrimidinic (AP) endonuclease in human cells. Previous structural studies have suggested a possible role for the Asp-210 residue of HAP1 in the...
Guliaev, Anton B., Hang, Bo, Singer, B.
1,N6-ethenoadenine adducts (εA) are formed by known environmental carcinogens and found to be removed by human alkylpurine-DNA N-glycosylase (APNG). 1,N6-ethanoadenine (ΕA) adducts differ from εA...
The exocyclic amino groups of ribonucleosides and deoxyribonucleosides react rapidly at ambient temperature with acetaldehyde and alcohols to yield mixed acetals [--NH--CH(CH3)OR]. Nucleotides and...
Singer, B, Chavez, F, Goodman, M F, Essigmann, J M, Dosanjh, M K
O6-Methylguanine (m6G) was incorporated site-specifically into two 25-base oligonucleotides differing only in the nucleotide on the 3' side of the modified base. Templates were primed with...
We previously reported that O4-alkyl dTTPs could replace, for short times, dTTP in polymer synthesis [Singer et al., PNAS 83, 26-32, 1986]. The reasons for such early termination of synthesis could...
Singer, B, Fraenkel-Conrat, H, Abbott, L G, Spengler, S J
N4- Methoxydeoxycytidine triphosphate ( mo4dCTP ) substitutes for dTTP in poly d[A-T] synthesis with E. coli DNA polymerase I (Pol I). In parallel experiments using as template-primer, poly d[G-C],...
Cultured human lymphoblasts (CCRF-CEM line) have DNA glycosylase activities, the specificities of which were investigated by using high-performance liquid chromatography. In addition to...
Singer, B, Spengler, S J, Fraenkel-Conrat, H, Kuśmierek, J T
In a previous paper, we reported that O4-methyl dTTP can be incorporated into poly(dA-dT) in place of thymidine without distortion of the helical structure, but on replication it could behave as...
Singer, B, Pulkrabek, P, Weinstein, I B, Grunberger, D
TMV RNA was modified by two bulky carcinogens, N-acetoxy-2-acetylamino-fluorene (AAAF) and (+/-)-7beta, 8alpha- dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo[alpha]pyrene (BPDE), and the...
1,N6-Ethenoadenosine (epsilon A) and 3,N4-Ethenocytidine (epsilon C) in copolymers with unmodified nucleosides were transcribed using DNA-dependent RNA polymerase in the presence of Mn2+. Nearest...
Singer, B, Pergolizzi, R G, Grunberger, D
Dinucleoside diphosphates of the general type pGpN have been prepared enzymatically using ribonuclease N1. Alkylated uridines or cytidines, which are products of carcinogens acting on nucleic acids,...
Bodell, W J, Singer, B, Thomas, G H, Cleaver, J E
The potent carcinogen, ethylnitrosourea, has been shown to ethylate oxygens, in preference to nitrogens, in the DNA of cultured cells. We have now studied the removal of seven ethyl derivatives in...
Binding of the bacteriophage T4 regA protein to mRNA targets: an initiator AUG is required.
Unnithan, S, Green, L, Morrissey, L, Binkley, J, Singer, B, Karam, J, ...
Bacteriophage T4 regA protein translationally represses the synthesis of a subset of early phage-induced proteins. The protein binds to the translation initiation site of at least two mRNAs and...
In non-aqueous solution, diazomethane and diazoethane react with the O2, O4 and N-3 sites of uridine, thymidine, 1-methyluracil and 1-methylthymine. Diazoethane has a higher affinity for alkylating...
Reconstitution of rods from tobacco mosaic virus protein and RNA modified with bulky carcinogens.
Fraenkel-Conrat, H, Singer, B, Takanami, Y, Santella, R M, Grunberger, D
Tobacco mosaic virus (TMV) RNA was treated with radioactive N-acetoxy-2-acetylaminofluorene (N-acetoxy-AAF) and (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10...
Effect of introduction of small alkyl groups on mRNA function.
Treatment of RNA with dimethyl sulfate methylates only nitrogens, preferentially the 7 position of guanosine, whereas treatment with ethylnitrosourea ethylates mainly oxygens, preferentially the...
Singer, B, Sági, J, Kuśmierek, J T
O2-and O4-alkyldeoxythymidine are among the four O-alkyl base-modified derivatives produced by the reaction of N-nitroso alkylating agents with nucleic acids in vitro and in vivo. We find that both...
Preston, B D, Singer, B, Loeb, L A
O4-Alkylthymine-DNA adducts have been implicated as causative lesions in chemical mutagenesis and carcinogenesis. To directly assess the mutagenic potential of these adducts in vivo, we have designed...
Preparation and template activities of polynucleotides containing O2- and O4-alkyluridine.
Singer, B, Fraenkel-Conrat, H, Kuśmierek, J T
O2-Ethyl-UDP and O4-methyl-UDP have been prepared and copolymerized in various proportions with UDP or CDP, using polynucleotide phosphorylase. The copolymers were used as templates for DNA-dependent...
In vitro discrimination of replicases acting on carcinogen-modified polynucleotide templates
Singer, B., Kuśmierek, J. T., Fraenkel-Conrat, H.
Three different poly(dC)s with modifications that block the N-3 of deoxycytidine were used as templates for polymer synthesis by Escherichia coli DNA polymerase I (EC 2.7.7.7). In contrast to...
Guliaev, Anton B., Hang, Bo, Singer, B.
The benzetheno exocyclic adduct of the cytosine (C) base (pBQ-C) is a product of reaction between DNA and a stable metabolite of the human carcinogen benzene, p-benzoquinone (pBQ). We reported...
Singer, B, Sun, L, Fraenkel-Conrat, H
Upon ethyl nitrosourea treatment of RNA of tobacco mosaic virus, up to four phosphodiester groups may be alkylated per molecule without chain breakage, as shown be sucrose gradient centrifugation....
Dosanjh, M K, Chenna, A, Kim, E, Fraenkel-Conrat, H, Samson, L, Singer, B
We have previously reported that human cells and tissues contain a 1,N6-ethenoadenine (epsilon A) binding protein, which, through glycosylase activity, releases both 3-methyladenine (m3A) and epsilon...
In vivo formation and persistence of modified nucleosides resulting from alkylating agents.
Alkylating agents are ubiquitous in the human environment and are continuously synthesized in vivo. Although many classes exist, interest has been focused on the N-nitroso compounds, since many are...
Early discharge of infants of low birth weight: a prospective study.
A total of 495 African infants of low birth weight were discharged from Harari Maternity Hospital, Salisbury, between October 1972 and September 1973. Criteria used for discharge were (a) no clinical...
Hang, B., Chenna, A., Fraenkel-Conrat, H., Singer, B.
The major human apurinic/apyrimidinic (AP) endonuclease (class II) is known to cleave DNA 5′ adjacent to an AP site, which is probably the most common DNA damage produced hydrolytically or by...
Hang, B., Singer, B., Margison, G. P., Elder, R. H.
It has previously been reported that 1,N6-ethenoadenine (ɛA), deaminated adenine (hypoxanthine, Hx), and 7,8-dihydro-8-oxoguanine (8-oxoG), but not 3,N4-ethenocytosine (ɛC), are released from DNA...
Hang, B., Medina, M., Fraenkel-Conrat, H., Singer, B.
Etheno adducts in DNA arise from multiple endogenous and exogenous sources. Of these adducts we have reported that, 1,N6-ethenoadenine (ɛA) and 3,N4-ethenocytosine (ɛC) are removed from DNA by two...
Chenna, A, Hang, B, Rydberg, B, Kim, E, Pongracz, K, Bodell, W J, ...
Benzene is a ubitiquous human environment mental carcinogen. One of the major metabolites is hydroquinone, which is oxidized in vivo to give p-benzoquinone (p-BQ). Both metabolites are toxic to human...
Evidence from in vitro replication that O6-methylguanine can adopt multiple conformations.
Dosanjh, M K, Loechler, E L, Singer, B
The effect of O6-methylguanine (m6G) on replication, in a partially double-stranded defined 25-base oligonucleotide, has been studied under nonlimiting conditions of unmodified dNTPs and over an...
Singer, B, Antoccia, A, Basu, A K, Dosanjh, M K, Fraenkel-Conrat, H, Gallagher, P E, ...
We previously described a protein, isolated from human tissues and cells, that bound to a defined double-stranded oligonucleotide containing a single site-specifically placed 1,N6-ethenoadenine. It...
Human cells contain protein specifically binding to a single 1,N6-ethenoadenine in a DNA fragment.
Rydberg, B, Dosanjh, M K, Singer, B
A human DNA binding protein has been characterized from cell-free extracts of liver, placenta, and cultured cells. This protein, apparent molecular mass approximately 35 kDa, to our knowledge, does...
Cheng, K C, Preston, B D, Cahill, D S, Dosanjh, M K, Singer, B, Loeb, L A
Vinyl chloride is a known human and rodent carcinogen that forms several cyclic base derivatives in DNA. The mutagenic potential of these derivatives has been examined in vitro but not in vivo. One...
Rothwell, D. G., Hang, B., Gorman, M. A., Freemont, P. S., Singer, B., Hickson, I. D.
HAP1, also known as APE/Ref-1, is the major apurinic/apyrimidinic (AP) endonuclease in human cells. Previous structural studies have suggested a possible role for the Asp-210 residue of HAP1 in the...
Guliaev, Anton B., Hang, Bo, Singer, B.
1,N6-ethenoadenine adducts (εA) are formed by known environmental carcinogens and found to be removed by human alkylpurine-DNA N-glycosylase (APNG). 1,N6-ethanoadenine (ΕA) adducts differ from εA...
The exocyclic amino groups of ribonucleosides and deoxyribonucleosides react rapidly at ambient temperature with acetaldehyde and alcohols to yield mixed acetals [--NH--CH(CH3)OR]. Nucleotides and...
Singer, B, Chavez, F, Goodman, M F, Essigmann, J M, Dosanjh, M K
O6-Methylguanine (m6G) was incorporated site-specifically into two 25-base oligonucleotides differing only in the nucleotide on the 3' side of the modified base. Templates were primed with...
We previously reported that O4-alkyl dTTPs could replace, for short times, dTTP in polymer synthesis [Singer et al., PNAS 83, 26-32, 1986]. The reasons for such early termination of synthesis could...
Singer, B, Fraenkel-Conrat, H, Abbott, L G, Spengler, S J
N4- Methoxydeoxycytidine triphosphate ( mo4dCTP ) substitutes for dTTP in poly d[A-T] synthesis with E. coli DNA polymerase I (Pol I). In parallel experiments using as template-primer, poly d[G-C],...
Cultured human lymphoblasts (CCRF-CEM line) have DNA glycosylase activities, the specificities of which were investigated by using high-performance liquid chromatography. In addition to...
Singer, B, Spengler, S J, Fraenkel-Conrat, H, Kuśmierek, J T
In a previous paper, we reported that O4-methyl dTTP can be incorporated into poly(dA-dT) in place of thymidine without distortion of the helical structure, but on replication it could behave as...
Singer, B, Pulkrabek, P, Weinstein, I B, Grunberger, D
TMV RNA was modified by two bulky carcinogens, N-acetoxy-2-acetylamino-fluorene (AAAF) and (+/-)-7beta, 8alpha- dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo[alpha]pyrene (BPDE), and the...
1,N6-Ethenoadenosine (epsilon A) and 3,N4-Ethenocytidine (epsilon C) in copolymers with unmodified nucleosides were transcribed using DNA-dependent RNA polymerase in the presence of Mn2+. Nearest...
Singer, B, Pergolizzi, R G, Grunberger, D
Dinucleoside diphosphates of the general type pGpN have been prepared enzymatically using ribonuclease N1. Alkylated uridines or cytidines, which are products of carcinogens acting on nucleic acids,...
Bodell, W J, Singer, B, Thomas, G H, Cleaver, J E
The potent carcinogen, ethylnitrosourea, has been shown to ethylate oxygens, in preference to nitrogens, in the DNA of cultured cells. We have now studied the removal of seven ethyl derivatives in...
Binding of the bacteriophage T4 regA protein to mRNA targets: an initiator AUG is required.
Unnithan, S, Green, L, Morrissey, L, Binkley, J, Singer, B, Karam, J, ...
Bacteriophage T4 regA protein translationally represses the synthesis of a subset of early phage-induced proteins. The protein binds to the translation initiation site of at least two mRNAs and...
In non-aqueous solution, diazomethane and diazoethane react with the O2, O4 and N-3 sites of uridine, thymidine, 1-methyluracil and 1-methylthymine. Diazoethane has a higher affinity for alkylating...
Reconstitution of rods from tobacco mosaic virus protein and RNA modified with bulky carcinogens.
Fraenkel-Conrat, H, Singer, B, Takanami, Y, Santella, R M, Grunberger, D
Tobacco mosaic virus (TMV) RNA was treated with radioactive N-acetoxy-2-acetylaminofluorene (N-acetoxy-AAF) and (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10...
Effect of introduction of small alkyl groups on mRNA function.
Treatment of RNA with dimethyl sulfate methylates only nitrogens, preferentially the 7 position of guanosine, whereas treatment with ethylnitrosourea ethylates mainly oxygens, preferentially the...
Singer, B, Sági, J, Kuśmierek, J T
O2-and O4-alkyldeoxythymidine are among the four O-alkyl base-modified derivatives produced by the reaction of N-nitroso alkylating agents with nucleic acids in vitro and in vivo. We find that both...
Preston, B D, Singer, B, Loeb, L A
O4-Alkylthymine-DNA adducts have been implicated as causative lesions in chemical mutagenesis and carcinogenesis. To directly assess the mutagenic potential of these adducts in vivo, we have designed...
Preparation and template activities of polynucleotides containing O2- and O4-alkyluridine.
Singer, B, Fraenkel-Conrat, H, Kuśmierek, J T
O2-Ethyl-UDP and O4-methyl-UDP have been prepared and copolymerized in various proportions with UDP or CDP, using polynucleotide phosphorylase. The copolymers were used as templates for DNA-dependent...
In vitro discrimination of replicases acting on carcinogen-modified polynucleotide templates
Singer, B., Kuśmierek, J. T., Fraenkel-Conrat, H.
Three different poly(dC)s with modifications that block the N-3 of deoxycytidine were used as templates for polymer synthesis by Escherichia coli DNA polymerase I (EC 2.7.7.7). In contrast to...
Guliaev, Anton B., Hang, Bo, Singer, B.
The benzetheno exocyclic adduct of the cytosine (C) base (pBQ-C) is a product of reaction between DNA and a stable metabolite of the human carcinogen benzene, p-benzoquinone (pBQ). We reported...
Singer, B, Sun, L, Fraenkel-Conrat, H
Upon ethyl nitrosourea treatment of RNA of tobacco mosaic virus, up to four phosphodiester groups may be alkylated per molecule without chain breakage, as shown be sucrose gradient centrifugation....
Dosanjh, M K, Chenna, A, Kim, E, Fraenkel-Conrat, H, Samson, L, Singer, B
We have previously reported that human cells and tissues contain a 1,N6-ethenoadenine (epsilon A) binding protein, which, through glycosylase activity, releases both 3-methyladenine (m3A) and epsilon...
In vivo formation and persistence of modified nucleosides resulting from alkylating agents.
Alkylating agents are ubiquitous in the human environment and are continuously synthesized in vivo. Although many classes exist, interest has been focused on the N-nitroso compounds, since many are...
Early discharge of infants of low birth weight: a prospective study.
A total of 495 African infants of low birth weight were discharged from Harari Maternity Hospital, Salisbury, between October 1972 and September 1973. Criteria used for discharge were (a) no clinical...