Combined exposure to X-irradiation followed by N-ethyl-N-nitrosourea treatment alters the frequency and spectrum of Ikaros point mutations in murine T-cell lymphoma

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Kakinuma, Shizuko, E-mail: skakinum@nirs.go.jp [Radiobiology for Children' s Health Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Nishimura, Mayumi; Amasaki, Yoshiko; Takada, Mayumi; Yamauchi, Kazumi; Sudo, Satomi; Shang, Yi [Radiobiology for Children' s Health Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Doi, Kazutaka; Yoshinaga, Shinji [Regulatory Sciences Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shimada, Yoshiya [Radiobiology for Children' s Health Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2012-09-01

Ionizing radiation is a well-known carcinogen, but its potency may be influenced by other environmental carcinogens, which is of practical importance in the assessment of risk. Data are scarce, however, on the combined effect of radiation with other environmental carcinogens and the underlying mechanisms involved. We studied the mode and mechanism of the carcinogenic effect of radiation in combination with N-ethyl-N-nitrosourea (ENU) using doses approximately equal to the corresponding thresholds. B6C3F1 mice exposed to fractionated X-irradiation (Kaplan's method) followed by ENU developed T-cell lymphomas in a dose-dependent manner. Radiation doses above an apparent threshold acted synergistically with ENU to promote lymphoma development, whereas radiation doses below that threshold antagonized lymphoma development. Ikaros, which regulates the commitment and differentiation of lymphoid lineage cells, is a critical tumor suppressor gene frequently altered in both human and mouse lymphomas and shows distinct mutation spectra between X-ray- and ENU-induced lymphomas. In the synergistically induced lymphomas, we observed a low frequency of LOH and an inordinate increase of Ikaros base substitutions characteristic of ENU-indcued point mutations, G:C to A:T at non-CpG, A:T to G:C, G:C to T:A and A:T to T:A. This suggests that radiation doses above an apparent threshold activate the ENU mutagenic pathway. This is the first report on the carcinogenic mechanism elicited by combined exposure to carcinogens below and above threshold doses based on the mutation spectrum of the causative gene. These findings constitute a basis for assessing human cancer risk following exposure to multiple carcinogens.

Genome-wide ENU mutagenesis in combination with high density SNP analysis and exome sequencing provides rapid identification of novel mouse models of developmental disease.

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Georgina Caruana

Full Text Available Mice harbouring gene mutations that cause phenotypic abnormalities during organogenesis are invaluable tools for linking gene function to normal development and human disorders. To generate mouse models harbouring novel alleles that are involved in organogenesis we conducted a phenotype-driven, genome-wide mutagenesis screen in mice using the mutagen N-ethyl-N-nitrosourea (ENU.ENU was injected into male C57BL/6 mice and the mutations transmitted through the germ-line. ENU-induced mutations were bred to homozygosity and G3 embryos screened at embryonic day (E 13.5 and E18.5 for abnormalities in limb and craniofacial structures, skin, blood, vasculature, lungs, gut, kidneys, ureters and gonads. From 52 pedigrees screened 15 were detected with anomalies in one or more of the structures/organs screened. Using single nucleotide polymorphism (SNP-based linkage analysis in conjunction with candidate gene or next-generation sequencing (NGS we identified novel recessive alleles for Fras1, Ift140 and Lig1.In this study we have generated mouse models in which the anomalies closely mimic those seen in human disorders. The association between novel mutant alleles and phenotypes will lead to a better understanding of gene function in normal development and establish how their dysfunction causes human anomalies and disease.

Genomic analysis of microRNA time-course expression in liver of mice treated with genotoxic carcinogen N-ethyl-N-nitrosourea

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Guo Lei

2010-10-01

Full Text Available Abstract Background Dysregulated expression of microRNAs (miRNAs has been previously observed in human cancer tissues and shown promise in defining tumor status. However, there is little information as to if or when expression changes of miRNAs occur in normal tissues after carcinogen exposure. Results To explore the possible time-course changes of miRNA expression induced by a carcinogen, we treated mice with one dose of 120 mg/kg N-ethyl-N-nitrosourea (ENU, a model genotoxic carcinogen, and vehicle control. The miRNA expression profiles were assessed in the mouse livers in a time-course design. miRNAs were isolated from the livers at days 1, 3, 7, 15, 30 and 120 after the treatment and their expression was determined using a miRNA PCR Array. Principal component analysis of the miRNA expression profiles showed that miRNA expression at post-treatment days (PTDs 7 and 15 were different from those at the other time points and the control. The number of differentially expressed miRNAs (DEMs changed over time (3, 5, 14, 32, 5 and 5 at PTDs 1, 3, 7, 15, 30 and 120, respectively. The magnitude of the expression change varied with time with the highest changes at PTDs 7 or 15 for most of the DEMs. In silico functional analysis of the DEMs at PTDs 7 and 15 indicated that the major functions of these ENU-induced DEMs were associated with DNA damage, DNA repair, apoptosis and other processes related to carcinogenesis. Conclusion Our results showed that many miRNAs changed their expression to respond the exposure of the genotoxic carcinogen ENU and the number and magnitude of the changes were highest at PTDs 7 to 15. Thus, one to two weeks after the exposure is the best time for miRNA expression sampling.

Longitudinal evaluation of an N-ethyl-N-nitrosourea-created murine model with normal pressure hydrocephalus.

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Ming-Jen Lee

Full Text Available BACKGROUND: Normal-pressure hydrocephalus (NPH is a neurodegenerative disorder that usually occurs late in adult life. Clinically, the cardinal features include gait disturbances, urinary incontinence, and cognitive decline. METHODOLOGY/PRINCIPAL FINDINGS: Herein we report the characterization of a novel mouse model of NPH (designated p23-ST1, created by N-ethyl-N-nitrosourea (ENU-induced mutagenesis. The ventricular size in the brain was measured by 3-dimensional micro-magnetic resonance imaging (3D-MRI and was found to be enlarged. Intracranial pressure was measured and was found to fall within a normal range. A histological assessment and tracer flow study revealed that the cerebral spinal fluid (CSF pathway of p23-ST1 mice was normal without obstruction. Motor functions were assessed using a rotarod apparatus and a CatWalk gait automatic analyzer. Mutant mice showed poor rotarod performance and gait disturbances. Cognitive function was evaluated using auditory fear-conditioned responses with the mutant displaying both short- and long-term memory deficits. With an increase in urination frequency and volume, the mutant showed features of incontinence. Nissl substance staining and cell-type-specific markers were used to examine the brain pathology. These studies revealed concurrent glial activation and neuronal loss in the periventricular regions of mutant animals. In particular, chronically activated microglia were found in septal areas at a relatively young age, implying that microglial activation might contribute to the pathogenesis of NPH. These defects were transmitted in an autosomal dominant mode with reduced penetrance. Using a whole-genome scan employing 287 single-nucleotide polymorphic (SNP markers and further refinement using six additional SNP markers and four microsatellite markers, the causative mutation was mapped to a 5.3-cM region on chromosome 4. CONCLUSIONS/SIGNIFICANCE: Our results collectively demonstrate that the p23-ST1

Identification of a rat model for usher syndrome type 1B by N-ethyl-N-nitrosourea mutagenesis-driven forward genetics

NARCIS (Netherlands)

Smits, B.M.; Peters, T.A.; Mul, J.D.; Croes, H.J.; Fransen, J.A.; Beynon, A.J.; Guryev, V.; Plasterk, R.; Cuppen, E.

2005-01-01

The rat is the most extensively studied model organism and is broadly used in biomedical research. Current rat disease models are selected from existing strains and their number is thereby limited by the degree of naturally occurring variation or spontaneous mutations. We have used ENU mutagenesis

Altered IFN-γ-mediated immunity and transcriptional expression patterns in N-Ethyl-N-nitrosourea-induced STAT4 mutants confer susceptibility to acute typhoid-like disease.

Science.gov (United States)

Eva, Megan M; Yuki, Kyoko E; Dauphinee, Shauna M; Schwartzentruber, Jeremy A; Pyzik, Michal; Paquet, Marilène; Lathrop, Mark; Majewski, Jacek; Vidal, Silvia M; Malo, Danielle

2014-01-01

Salmonella enterica is a ubiquitous Gram-negative intracellular bacterium that continues to pose a global challenge to human health. The etiology of Salmonella pathogenesis is complex and controlled by pathogen, environmental, and host genetic factors. In fact, patients immunodeficient in genes in the IL-12, IL-23/IFN-γ pathway are predisposed to invasive nontyphoidal Salmonella infection. Using a forward genomics approach by N-ethyl-N-nitrosourea (ENU) germline mutagenesis in mice, we identified the Ity14 (Immunity to Typhimurium locus 14) pedigree exhibiting increased susceptibility following in vivo Salmonella challenge. A DNA-binding domain mutation (p.G418_E445) in Stat4 (Signal Transducer and Activator of Transcription Factor 4) was the causative mutation. STAT4 signals downstream of IL-12 to mediate transcriptional regulation of inflammatory immune responses. In mutant Ity14 mice, the increased splenic and hepatic bacterial load resulted from an intrinsic defect in innate cell function, IFN-γ-mediated immunity, and disorganized granuloma formation. We further show that NK and NKT cells play an important role in mediating control of Salmonella in Stat4(Ity14/Ity14) mice. Stat4(Ity14/Ity14) mice had increased expression of genes involved in cell-cell interactions and communication, as well as increased CD11b expression on a subset of splenic myeloid dendritic cells, resulting in compromised recruitment of inflammatory cells to the spleen during Salmonella infection. Stat4(Ity14/Ity14) presented upregulated compensatory mechanisms, although inefficient and ultimately Stat4(Ity14/Ity14) mice develop fatal bacteremia. The following study further elucidates the pathophysiological impact of STAT4 during Salmonella infection.

Defective immuno- and thymoproteasome assembly causes severe immunodeficiency

DEFF Research Database (Denmark)

Treise, Irina; Huber, Eva M.; Klein-Rodewald, Tanja

2018-01-01

By N-ethyl-N-nitrosourea (ENU) mutagenesis, we generated the mutant mouse line TUB6 that is characterised by severe combined immunodeficiency (SCID) and systemic sterile autoinflammation in homozygotes, and a selective T cell defect in heterozygotes. The causative missense point mutation results...

Effect of ethyl-, methyl- and hydroxyethyl-nitrosourea on the mouse testis

Energy Technology Data Exchange (ETDEWEB)

Oakberg, E.F.; Crosthwait, C.D.

1983-01-01

Hybrid male 101 x C3HF/sub 1/ mice were given intraperitoneal injections of methyl-, ethyl- and hydroxyethyl-nitrosourea and killed 3-16 days later. All compounds were similar in that all differentiating spermatogonia from type A/sub 1/ to early type B were killed by 50 mg/kg and higher doses of ENU and by 75 mg/kg MNU. Cells exposed to leptotene to 100 and 250 mg/kg ENU and 455 mg/kg HENU showed a delayed response with degeneration in pachytene 5 days later. Labeling prior to exposure to ENU indicated that the effect of stage of the mitotic cycle on sensitivity to cell killing is less marked than for radiation. This may be the explanation for the s-shaped mutation induction curve obtained with ENU in contrast to the humped dose-response curve observed for radiation.

A Mutant Mouse with a Highly Specific Contextual Fear-Conditioning Deficit Found in an N-Ethyl-N-Nitrosourea (ENU) Mutagenesis Screen

Science.gov (United States)

Pletcher, Mathew T.; Wiltshire, Tim; Tarantino, Lisa M.; Mayford, Mark; Reijmers, Leon G.; Coats, Jennifer K.

2006-01-01

Targeted mutagenesis in mice has shown that genes from a wide variety of gene families are involved in memory formation. The efficient identification of genes involved in learning and memory could be achieved by random mutagenesis combined with high-throughput phenotyping. Here, we provide the first report of a mutagenesis screen that has…

Circadian Biology and Sleep: Missing Links in Obesity and Metabolism

Science.gov (United States)

2009-05-01

large-scale N-ethyl-N- nitrosourea (ENU) mutagenesis screen using a wide range of nervous system and behavioral phenotypes, we have identified new...physiology. In addition to storing energy in the form of triglycerides, WAT is now known to act as an active endocrine tissue via the synthesis and

The effects of X-irradiation, N-ethyl-N-nitrosourea or combined treatment on O6-alkylguanine-DNA alkyltransferase activity in fetal rat brain and liver and the induction of CNS tumours

International Nuclear Information System (INIS)

Stammberger, I.; Nice, L.; Schmahl, W.

1990-01-01

Wistar rats were treated in utero on day 16 of gestation either by X-irradiation, N-ethyl-N-nitrosourea (ENU), or both in combination. The O 6 -alkylguanine-DNA alkyltransferase (AT) activity of the fetal brain and liver was analyzed and long-term observations were made to reveal any relationship between the O 6 -ethylguanine repair capability and tumour incidence in the organs of the offspring. The AT activity in the brain was affected to the same extent in the fetuses as in the dams. There was a 60.9% decrease in AT activity in fetuses 24 h after ENU treatment. This correlates with a significant increase in the incidence of brain tumours in the treated offspring (44.1%) compared to control animals. The inductive effect of X-irradiation on AT activity corresponded in turn with a reduction of the incidence of tumours after the combined treatment. In the liver of the rat fetuses, there was generally no effect of treatment on AT activity in contrast to the results obtained for the dams, where an increased AT activity was observed. There were no tumours of the liver observed in the offspring after either treatment alone or after combined treatment. It is suggested that the combined treatment of rat fetuses could significantly reduce the incidence of brain tumours in adult life. (author)

The serotonin transporter knockout rat : A review

NARCIS (Netherlands)

Olivier, Jocelien; Cools, Alexander; Ellenbroek, Bart A.; Cuppen, E.; Homberg, Judith; Kalueff, Allan V.; LaPorte, Justin L.

2010-01-01

This chapter dicusses the most recent data on the serotonin transporter knock-out rat, a unique rat model that has been generated by target-selected N-ethyl-N-nitrosourea (ENU) driven mutagenesis. The knock-out rat is the result of a premature stopcodon in the serotonin transporter gene, and the

Use of gamma-radiation and ethyl nitrosourea independently and in combination in experimental mutagenesis in peas. Pt. 1

International Nuclear Information System (INIS)

Lejtao, Zh.; Petkova, S.; Dzhondzhurov, L.

1987-01-01

Dry seeds from field peas cv. Uladovskij 303 were treated for three years with gamma rays (280 to 250 rad/min) and with the powerful chemical mutagen/carcinogen ethyl nitrosourea - ENU (solution prepared in phosphate buffer, ph=6.0). The seeds were exposed to ENU for 6 h, washed out for 30 min and dried for 30 min. The following qualitative indices were investigated: emergence; survival; sterility; lethality; vegetation period and plant's height one month after sowing. They could be used successfully to determine the injurious effects of the mutagens. A clear-cut dependence on the used dose and concentration was observed independently if the mutagens were applied separately or in combination. Quantitative indices determined at the end of the vegetation: branches per plant, sterile nodes, nodes per plant, number of pods and seeds per plant as well as plant's height did not show any clear-cut tendency when treatments were made in combination. Their determination, in field conditions, seemed to be without significance. As theoretically it was expected, pre-radiation use of ENU leads to a stronger injurious effect in comparison to that of post-radiation treatment. Concerning induced leaf-spots (leaf aberrations) in M 1 -generation, the results were in complete disagreement with the theory: pre-radiation treatment with ENU (at combination 3.12 mM ENU + 12 krad), which provoked a very high injury (lethality - 80-90%), showed a very little percent of plants with a high level of leaf aberrations. On the contrary, post-radiation treatment with ENU (lethality - 40-60%) caused a high level of leaf aberrations in greater number of plants. The presence of 'gamma plantlets' phenomenon is proposed for possible explanation. 3 tabs.; 9 refs

The effects of X-irradiation, N-ethyl-N-nitrosourea or combined treatment on O sup 6 -alkylguanine-DNA alkyltransferase activity in fetal rat brain and liver and the induction of CNS tumours

Energy Technology Data Exchange (ETDEWEB)

Stammberger, I.; Nice, L. (Muenchen Univ. (Germany, F.R.). Walter-Straub-Institut fuer Pharmakologie und Toxikologie); Schmahl, W. (Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Pathologie)

1990-02-01

Wistar rats were treated in utero on day 16 of gestation either by X-irradiation, N-ethyl-N-nitrosourea (ENU), or both in combination. The O{sup 6}-alkylguanine-DNA alkyltransferase (AT) activity of the fetal brain and liver was analyzed and long-term observations were made to reveal any relationship between the O{sup 6}-ethylguanine repair capability and tumour incidence in the organs of the offspring. The AT activity in the brain was affected to the same extent in the fetuses as in the dams. There was a 60.9% decrease in AT activity in fetuses 24 h after ENU treatment. This correlates with a significant increase in the incidence of brain tumours in the treated offspring (44.1%) compared to control animals. The inductive effect of X-irradiation on AT activity corresponded in turn with a reduction of the incidence of tumours after the combined treatment. In the liver of the rat fetuses, there was generally no effect of treatment on AT activity in contrast to the results obtained for the dams, where an increased AT activity was observed. There were no tumours of the liver observed in the offspring after either treatment alone or after combined treatment. It is suggested that the combined treatment of rat fetuses could significantly reduce the incidence of brain tumours in adult life. (author).

Enzymatic removal of O6-ethylguanine from mitochondrial DNA in rat tissues exposed to N-ethyl-N-nitrosourea in vivo

International Nuclear Information System (INIS)

Satoh, M.S.; Huh, N.; Rajewsky, M.F.; Kuroki, T.

1988-01-01

DNA repair is essential for maintaining the integrity of the genetic material, and a number of DNA repair mechanisms have been fairly well characterized for the nuclear DNA of eukaryotic cells as well as prokaryotes. However, little is know about DNA repair in mitochondria. Using highly sensitive immunoanalytical methods to detect specific DNA alkylation products, the authors found active removal of O 6 -ethyl-2'-deoxyguanosine (O 6 -EtdGuo) from rat liver mitochondrial DNA after pulse-exposure to N-ethyl-N-nitrosourea in vivo. In the kidney, O 6 -EtdGuo was removed from mitochondrial DNA with moderate efficiency, but nearly no removal was observed from the DNA of brain mitochondria. Among the rat tissues examined, the kinetics of O 6 -EtdGuo elimination from mitochondrial DNA was very similar to the kinetics of removal from nuclear DNA. O 4 -Ethyl-2'-deoxythymidine, another premutagenic DNA ethylation product, was stable in both mitochondrial and nuclear DNA of rat liver

ENU-induced phenovariance in mice: inferences from 587 mutations

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Arnold Carrie N

2012-10-01

Full Text Available Abstract Background We present a compendium of N-ethyl-N-nitrosourea (ENU-induced mouse mutations, identified in our laboratory over a period of 10 years either on the basis of phenotype or whole genome and/or whole exome sequencing, and archived in the Mutagenetix database. Our purpose is threefold: 1 to formally describe many point mutations, including those that were not previously disclosed in peer-reviewed publications; 2 to assess the characteristics of these mutations; and 3 to estimate the likelihood that a missense mutation induced by ENU will create a detectable phenotype. Findings In the context of an ENU mutagenesis program for C57BL/6J mice, a total of 185 phenotypes were tracked to mutations in 129 genes. In addition, 402 incidental mutations were identified and predicted to affect 390 genes. As previously reported, ENU shows strand asymmetry in its induction of mutations, particularly favoring T to A rather than A to T in the sense strand of coding regions and splice junctions. Some amino acid substitutions are far more likely to be damaging than others, and some are far more likely to be observed. Indeed, from among a total of 494 non-synonymous coding mutations, ENU was observed to create only 114 of the 182 possible amino acid substitutions that single base changes can achieve. Based on differences in overt null allele frequencies observed in phenotypic vs. non-phenotypic mutation sets, we infer that ENU-induced missense mutations create detectable phenotype only about 1 in 4.7 times. While the remaining mutations may not be functionally neutral, they are, on average, beneath the limits of detection of the phenotypic assays we applied. Conclusions Collectively, these mutations add to our understanding of the chemical specificity of ENU, the types of amino acid substitutions it creates, and its efficiency in causing phenovariance. Our data support the validity of computational algorithms for the prediction of damage caused by

Synthesis and purification of 14C N-2-hydroxyethyl-N-nitrosourea

International Nuclear Information System (INIS)

Perez, G.; Possagno, E.; Caponecchi, G.; Lilla, E.

1986-01-01

14 C N-2-hydroxyethyl-N-nitrosourea was prepared at a specific activity of 30 mCi/mmol and 1.29 mCi/mmol by a two-step synthetic sequence using 14 C ethanolamine as the labelled precursor. Its purification was performed by HPLC using a Lichrosorb-DIOL column eluted by ethyl ether. The overall radiochemical yield was 10%. (author)

Synthesis and purification of /sup 14/C N-2-hydroxyethyl-N-nitrosourea

Energy Technology Data Exchange (ETDEWEB)

Perez, G.; Possagno, E.; Caponecchi, G.; Lilla, E.; Polcaro, C.

1986-04-01

/sup 14/C N-2-hydroxyethyl-N-nitrosourea was prepared at a specific activity of 30 mCi/mmol and 1.29 mCi/mmol by a two-step synthetic sequence using /sup 14/C ethanolamine as the labelled precursor. Its purification was performed by HPLC using a Lichrosorb-DIOL column eluted by ethyl ether. The overall radiochemical yield was 10%.

[Synthesis of new nitrosoureas].

Science.gov (United States)

Papadaki-Valiraki, A; Siatra-Papastaikoudi, T; Skaltsounis, A L; Roussakis, C

1989-01-01

Two chemical pathways were used for the synthesis of three new N'-(2-chloroethyl)-N-[2-(4-alkoxyphenylthio)ethyl]-N'-nitrosoureas and two new N'-(2-chloroethyl)-N)[2-(4-alkoxyphenyl-thio)ethyl]-N-nitrosoureas . The study of the cytotoxicity of the three N'-nitrosoureas, was carried out in two experimental models (P 388 and NSCLCN6).

Compound list: N-methyl-N-nitrosourea [Open TG-GATEs

Lifescience Database Archive (English)

Full Text Available N-methyl-N-nitrosourea MNU 00164 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LA...TEST/Human/in_vitro/N-methyl-N-nitrosourea.Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-...tggates/LATEST/Rat/in_vivo/Liver/Single/N-methyl-N-nitrosourea.Rat.in_vivo.Liver.Single.zip ...

Reaction products from N-methyl-N-nitrosourea and deoxyribonucleic acid containing thymidine residues. Synthesis and identification of a new methylation product, O4-methyl-thymidine

Science.gov (United States)

Lawley, P. D.; Orr, D. J.; Shah, S. A.; Farmer, P. B.; Jarman, M.

1973-01-01

1. DNA was treated with N-methyl-N-nitrosourea at pH7–8, 37°C, degraded to yield 3- and 7-methylpurines and deoxyribonucleosides and the reaction products were separated by chromatography on ion-exchange resins. The following methods for identification and determination of products were used: with unlabelled N-methyl-N-nitrosourea, u.v. absorption; use of methyl-14C-labelled N-methyl-N-nitrosourea and use of [14C]thymine-labelled DNA. 2. The synthesis of O4-methylthymidine and its identification by u.v. and mass spectroscopy are reported. 3. 3-Methylthymidine and O4-methylthymidine were found as methylation products from N-methyl-N-nitrosourea with thymidine and with DNA, in relatively small yields. Unidentified products containing thymine were found in enzymic digests of N-methyl-N-nitrosourea-treated DNA, which may be phosphotriesters. 4. The possible role of formation of methylthymines in mutagenesis by N-methyl-N-nitrosourea is discussed. PMID:4798180

ENU mutagenesis identifies mice with morbid obesity and severe hyperinsulinemia caused by a novel mutation in leptin.

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Chen-Jee Hong

Full Text Available BACKGROUND: Obesity is a multifactorial disease that arises from complex interactions between genetic predisposition and environmental factors. Leptin is central to the regulation of energy metabolism and control of body weight in mammals. METHODOLOGY/PRINCIPAL FINDINGS: To better recapitulate the complexity of human obesity syndrome, we applied N-ethyl-N-nitrosourea (ENU mutagenesis in combination with a set of metabolic assays in screening mice for obesity. Mapping revealed linkage to the chromosome 6 within a region containing mouse Leptin gene. Sequencing on the candidate genes identified a novel T-to-A mutation in the third exon of Leptin gene, which translates to a V145E amino acid exchange in the leptin propeptide. Homozygous Leptin(145E/145E mutant mice exhibited morbid obesity, accompanied by adipose hypertrophy, energy imbalance, and liver steatosis. This was further associated with severe insulin resistance, hyperinsulinemia, dyslipidemia, and hyperleptinemia, characteristics of human obesity syndrome. Hypothalamic leptin actions in inhibition of orexigenic peptides NPY and AgRP and induction of SOCS1 and SOCS3 were attenuated in Leptin(145E/145E mice. Administration of exogenous wild-type leptin attenuated hyperphagia and body weight increase in Leptin(145E/145E mice. However, mutant V145E leptin coimmunoprecipitated with leptin receptor, suggesting that the V145E mutation does not affect the binding of leptin to its receptor. Molecular modeling predicted that the mutated residue would form hydrogen bond with the adjacent residues, potentially affecting the structure and formation of an active complex with leptin receptor within that region. CONCLUSIONS/SIGNIFICANCE: Thus, our evolutionary, structural, and in vivo metabolic information suggests the residue 145 as of special function significance. The mouse model harboring leptin V145E mutation will provide new information on the current understanding of leptin biology and novel mouse

Spectra of molecular changes induced in DNA of Drosophila spermatozoa by 1-ethyl-1-nitrosourea and X-rays

International Nuclear Information System (INIS)

Batzer, M.A.; Fossett, N.G.; Lee, W.R.; Louisiana State Univ., Baton Rouge; Tedeschi, B.; Tucker, A.; Kilroy, G.; Arbour, P.

1988-01-01

Mutations induced in Drosophila spermatozoa at the alcohol dehydrogenase Adh locus by 1-ethyl-1-nitrosourea (ENU) were compared to X-ray-induced mutations using genetic tests for complementation, southern blotting, western blotting and northern blotting. 8 of 10 ENU-induced mutations complemented all known adjacent loci and were presumed to be intragenic. In contrast, 8 of 30 X-ray-induced mutations were intragenic. The interpretation of these results is that in spermatozoa X-rays induce primarily deletions that either produce deficiencies of the Adh locus or nonsense mutations within the locus, whereas ENU induces primarily missense mutations. This forward mutation assay based on loss of enzymatic activity efficiently recovered a broad spectrum of mutations ranging from missense to intragenic deletions and multi-locus deficiencies. Only 3 of these 40 mutations produced a polypeptide detectable as an electrophoretic variant. 37 refs.; 6 figs.; 2 tabs

N-(2-chloroethyl)-N-nitrosoureas covalently bound to nonionic and monocationic lexitropsin dipeptides. Synthesis, DNA affinity binding characteristics, and reactions with 32P-end-labeled DNA

International Nuclear Information System (INIS)

Church, K.M.; Wurdeman, R.L.; Zhang, Yi; Chen, Faxian; Gold, B.

1990-01-01

The synthesis and characterization of a series of compounds that contain an N-alkyl-N-nitrosourea functionality linked to DNA minor groove binding bi- and tripeptides (lexitropsins or information-reading peptides) based on methylpyrrole-2-carboxamide subunits are described. The lexitropsins (lex) synthesized have either a 3-(dimethylamino)propyl or propyl substituent on the carboxyl terminus. The preferred DNA affinity binding sequences of these compounds were footprinted in 32 P-end-labeled restriction fragments with methidiumpropyl-EDTA·Fe(II), and in common with other structural analogues, e.g., distamycin and netropsin, these nitrosoureas recognize A-T-rich runs. The affinity binding of the compound with the dimethylamino terminus, which is ionized at near-neutral pH, appeared stronger than that observed for the neutral dipeptide. The sequence specificity for DNA alkylation by (2-chloroethyl)nitrosourea-lex dipeptides (Cl-ENU-lex), with neutral and charged carboxyl termini, using 32 P-end-labeled restriction fragments, was determined by the conversion of the adducted sites into single-strand breaks by sequential heating at neutral pH and exposure to base. The DNA cleavage sites were visualized by polyacrylamide gel electrophoresis and autoradiography. Linking the Cl-ENU moiety to minor groove binders is a viable strategy to qualitatively and quantitatively control the delivery and release of the ultimate DNA alkylating agent in a sequence-dependent fashion

ENU mutagenesis reveals a novel phenotype of reduced limb strength in mice lacking fibrillin 2.

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Gaynor Miller

2010-02-01

Full Text Available Fibrillins 1 (FBN1 and 2 (FBN2 are components of microfibrils, microfilaments that are present in many connective tissues, either alone or in association with elastin. Marfan's syndrome and congenital contractural arachnodactyly (CCA result from dominant mutations in the genes FBN1 and FBN2 respectively. Patients with both conditions often present with specific muscle atrophy or weakness, yet this has not been reported in the mouse models. In the case of Fbn1, this is due to perinatal lethality of the homozygous null mice making measurements of strength difficult. In the case of Fbn2, four different mutant alleles have been described in the mouse and in all cases syndactyly was reported as the defining phenotypic feature of homozygotes.As part of a large-scale N-ethyl-N-nitrosourea (ENU mutagenesis screen, we identified a mouse mutant, Mariusz, which exhibited muscle weakness along with hindlimb syndactyly. We identified an amber nonsense mutation in Fbn2 in this mouse mutant. Examination of a previously characterised Fbn2-null mutant, Fbn2(fp, identified a similar muscle weakness phenotype. The two Fbn2 mutant alleles complement each other confirming that the weakness is the result of a lack of Fbn2 activity. Skeletal muscle from mutants proved to be abnormal with higher than average numbers of fibres with centrally placed nuclei, an indicator that there are some regenerating muscle fibres. Physiological tests indicated that the mutant muscle produces significantly less maximal force, possibly as a result of the muscles being relatively smaller in Mariusz mice.These findings indicate that Fbn2 is involved in integrity of structures required for strength in limb movement. As human patients with mutations in the fibrillin genes FBN1 and FBN2 often present with muscle weakness and atrophy as a symptom, Fbn2-null mice will be a useful model for examining this aspect of the disease process further.

Phenotype screening for genetically deermined age-onset disorders and increased longevity in ENU-mutagenized mice

Energy Technology Data Exchange (ETDEWEB)

Johnson, Dabney K [ORNL; Rinchik, Eugene M [ORNL; Moustaid-Moussa, Naima [University of Tennessee, Knoxville (UTK); Miller, Darla R [ORNL; Williams, Robert [University of Tennessee Health Science Center, Memphis; Michaud III, Edward J [ORNL; Jablonski, Monica M. [University of Tennessee Health Science Center, Memphis; Elberger, Andrea [University of Tennessee Health Science Center, Memphis; Hamre, Kristin M. [University of Tennessee Health Science Center, Memphis; Smeyne, Richard [St. Jude Children' s Research Hospital; Chesler, Elissa J [ORNL; Goldowitz, Daniel [University of Tennessee Health Science Center, Memphis

2005-01-01

With the goal of discovering genes that contribute to late-onset neurological and ocular disorders and also genes that extend the healthy life span in mammals, we are phenotyping mice carrying new mutations induced by the chemical N-ethyl-N-nitrosourea (ENU). The phenotyping plan includes basic behavioral, neurohistological, and vision testing in sibling cohorts of mice aged to 18 months, and then evaluation for markers of growth trajectory and stress response in these same cohorts aged up to 28 months. Statistical outliers are identified by comparison to test results of similar aged cohorts, and potential mutants are recovered for re-aging to confirm heritability of the phenotype.

Simulation and estimation of gene number in a biological pathway using almost complete saturation mutagenesis screening of haploid mouse cells.

Science.gov (United States)

Tokunaga, Masahiro; Kokubu, Chikara; Maeda, Yusuke; Sese, Jun; Horie, Kyoji; Sugimoto, Nakaba; Kinoshita, Taroh; Yusa, Kosuke; Takeda, Junji

2014-11-24

Genome-wide saturation mutagenesis and subsequent phenotype-driven screening has been central to a comprehensive understanding of complex biological processes in classical model organisms such as flies, nematodes, and plants. The degree of "saturation" (i.e., the fraction of possible target genes identified) has been shown to be a critical parameter in determining all relevant genes involved in a biological function, without prior knowledge of their products. In mammalian model systems, however, the relatively large scale and labor intensity of experiments have hampered the achievement of actual saturation mutagenesis, especially for recessive traits that require biallelic mutations to manifest detectable phenotypes. By exploiting the recently established haploid mouse embryonic stem cells (ESCs), we present an implementation of almost complete saturation mutagenesis in a mammalian system. The haploid ESCs were mutagenized with the chemical mutagen N-ethyl-N-nitrosourea (ENU) and processed for the screening of mutants defective in various steps of the glycosylphosphatidylinositol-anchor biosynthetic pathway. The resulting 114 independent mutant clones were characterized by a functional complementation assay, and were shown to be defective in any of 20 genes among all 22 known genes essential for this well-characterized pathway. Ten mutants were further validated by whole-exome sequencing. The predominant generation of single-nucleotide substitutions by ENU resulted in a gene mutation rate proportional to the length of the coding sequence, which facilitated the experimental design of saturation mutagenesis screening with the aid of computational simulation. Our study enables mammalian saturation mutagenesis to become a realistic proposition. Computational simulation, combined with a pilot mutagenesis experiment, could serve as a tool for the estimation of the number of genes essential for biological processes such as drug target pathways when a positive selection of

Activated N-nitrosocarbamates for regioselective synthesis of N-nitrosoureas.

Science.gov (United States)

Martinez, J; Oiry, J; Imbach, J L; Winternitz, F

1982-02-01

A practical and convenient method for synthesizing antitumor compounds, N-alkyl-N-nitrosoureas, regioselectively nitrosated on the nitrogen atom bearing the alkyl group is proposed. N-Alkyl-N-nitrosocarbamates are interesting intermediates in these syntheses and yield, by reaction with amino compounds, the regioselectively nitrosated N-alkyl-N-nitrosoureas. As an interesting example, N,N'-bis[(2-chloroethyl)nitrosocarbamoyl]cystamine, a new attractive oncostatic derivative, has been prepared. The cytotoxic activity of these various compounds were tested on L1210 leukemia.

Experimental induction of ovarian Sertoli cell tumors in rats by N-nitrosoureas.

Science.gov (United States)

Maekawa, A; Onodera, H; Tanigawa, H; Furuta, K; Kanno, J; Ogiu, T; Hayashi, Y

1987-01-01

Spontaneous ovarian tumors are very rare in ACI, Wistar, F344 and Donryu rats; the few neoplasms found are of the granulosa/theca cell type. Ovarian tumors were also rare in these strains of rats when given high doses of N-alkyl-N-nitrosoureas continuously in the drinking water for their life-span; however, relatively high incidences of Sertoli cell tumors or Sertoli cell tumors mixed with granulosa cell tumors were induced in Donryu rats after administration of either a 400 ppm N-ethyl-N-nitrosourea solution in the drinking water for 4 weeks or as a single dose of 200 mg N-propyl-N-nitrosourea per kg body weight by stomach tube. Typical Sertoli cell tumors consisted of solid areas showing tubular formation. The tubules were lined by tall, columnar cells, with abundant, faintly eosinophilic, often vacuolated cytoplasm, and basally oriented, round nuclei, resembling seminiferous tubules in the testes. In some cases, Sertoli cell tumor elements were found mixed with areas of granulosa cells. The induction of ovarian Sertoli cell tumors in Donryu rats by low doses of nitrosoureas may provide a useful model for these tumors in man. Images PLATE 1. PLATE 2. PLATE 3. PLATE 4. PLATE 5. PLATE 6. PLATE 7. PLATE 8. PLATE 9. PLATE 10. PLATE 11. PLATE 12. PLATE 13. PLATE 14. PLATE 15. PLATE 16. PMID:3665856

Alkylation damage causes MMR-dependent chromosomal instability in vertebrate embryos.

NARCIS (Netherlands)

Feitsma, H.; Akay, A.; Cuppen, E.

2008-01-01

S(N)1-type alkylating agents, like N-methyl-N-nitrosourea (MNU) and N-ethyl-N-nitrosourea (ENU), are potent mutagens. Exposure to alkylating agents gives rise to O(6)-alkylguanine, a modified base that is recognized by DNA mismatch repair (MMR) proteins but is not repairable, resulting in

Inhibition of protein synthesis by N-methyl-N-nitrosourea in vivo

Science.gov (United States)

Kleihues, P.; Magee, P. N.

1973-01-01

1. The intraperitoneal injection of N-methyl-N-nitrosourea (100mg/kg) caused a partial inhibition of protein synthesis in several organs of the rat, the maximum effect occurring after 2–3h. 2. In the liver the inhibition of protein synthesis was paralleled by a marked disaggregation of polyribosomes and an increase in ribosome monomers and ribosomal subunits. No significant breakdown of polyribosomes was found in adult rat brains although N-methyl-N-nitrosourea inhibited cerebral and hepatic protein synthesis to a similar extent. In weanling rats N-methyl-N-nitrosourea caused a shift in the cerebral polyribosome profile similar to but less marked than that in rat liver. 3. Reaction of polyribosomal RNA with N-[14C]methyl-N-nitrosourea in vitro did not lead to a disaggregation of polyribosomes although the amounts of 7-methylguanine produced were up to twenty times higher than those found after administration of sublethal doses in vivo. 4. It was concluded that changes in the polyribosome profile induced by N-methyl-N-nitrosourea may reflect the mechanism of inhibition of protein synthesis rather than being a direct consequence of the methylation of polyribosomal mRNA. PMID:4774397

Enhancement by O6-benzyl-N2-acetylguanosine of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea therapeutic index on nude mice bearing resistant human melanoma.

Science.gov (United States)

Debiton, E.; Cussac-Buchdhal, C.; Mounetou, E.; Rapp, M.; Dupuy, J. M.; Maurizis, J. C.; Veyre, A.; Madelmont, J. C.

1997-01-01

The exposure of cells to O6-benzyl-N2-acetylguanosine (BNAG) and several guanine derivatives is known to reduce the activity of O6-alkylguanine-DNA alkyltransferase (MGMT) and to enhance the sensitivity of Mer+ (methyl enzyme repair positive) tumour cells to chloroethylnitrosoureas (CENUs) in vitro and in vivo. High water solubility and the pharmacokinetic properties of BNAG make it a candidate for simultaneous administration with CENUs by the i.v. route in human clinical use. In vivo we have shown previously that BNAG significantly increases the efficiency of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea (cystemustine) against M4Beu melanoma cells (Mer+) through its cytostatic activity by the i.p. route, but also increases its toxicity. To investigate the toxicity of BNAG and cystemustine when administered simultaneously in mice, we compared the maximum tolerated dose and LD50 doses of cystemustine alone or in combination with 40 mg kg(-1) BNAG by the i.p. route. The toxicity of cystemustine was enhanced by a factor of almost 1.44 when combined with BNAG. To compare the therapeutic index of cystemustine alone and the cystemustine/BNAG combination, pharmacological tests were carried out in nude mice bearing Mer+ M4Beu human melanoma cells. Isotoxic doses were calculated using the 1.44 ratio. The treatments were administered three times by the i.v. route on days 1, 5 and 9 after s.c. inoculation of tumour cells. Although the toxicities of the treatments were equal, BNAG strongly enhanced tumour growth inhibition. These results demonstrate the increase of the therapeutic index of cystemustine by BNAG and justify the use of BNAG to enhance nitrosourea efficiency in vivo by i.v. co-injection. PMID:9365163

N-ethyl-N-nitrosourea-induced null mutation at the mouse Car-2 locus: An animal model for human carbonic anhydrase II deficiency syndrome

International Nuclear Information System (INIS)

Lewis, S.E.; Barnett, L.B.; Erickson, R.P.; Venta, P.J.; Tashian, R.E.

1988-01-01

Electrophoretic screening of (C57BL/6J x DBA/2J)F 1 progeny of male mice treated with N-ethyl-N-nitrosourea revealed a mouse that lacked the paternal carbonic anhydrase II (Ca II). Breeding tests showed that this trait was heritable and due to a null mutation at the Car-2 locus on chromosome 3. Like humans with the same inherited enzyme defect, animals homozygous for the new null allele are runted and have renal tubular acidosis. However, the prominent osteopetrosis found in humans with CA II deficiency could be detected even in very old homozygous null mice. A molecular analysis of the deficient mice shows that the mutant gene is not deleted and is transcribed. The CA II protein, which is normally expressed in most tissues, could not be detected by immunodiffusion analysis in any tissues of the CA II-deficient mice, suggesting a nonsense or a missense mutation at the Car-2 locus

Mutagenic effect of radionuclides incorporated into DNA of Drosophila melanogaster. Progress report, July 16, 1983-June 30, 1984

International Nuclear Information System (INIS)

Lee, W.R.

1984-01-01

Progress is reported in the development of methods for economically analyzing mutants at the molecular level so that mutants induced by x-rays, N-ethyl-N-nitrosourea (ENU) and tritium could be classified

Sensitized mutagenesis screen in Factor V Leiden mice identifies thrombosis suppressor loci.

Science.gov (United States)

Westrick, Randal J; Tomberg, Kärt; Siebert, Amy E; Zhu, Guojing; Winn, Mary E; Dobies, Sarah L; Manning, Sara L; Brake, Marisa A; Cleuren, Audrey C; Hobbs, Linzi M; Mishack, Lena M; Johnston, Alexander J; Kotnik, Emilee; Siemieniak, David R; Xu, Jishu; Li, Jun Z; Saunders, Thomas L; Ginsburg, David

2017-09-05

Factor V Leiden ( F5 L ) is a common genetic risk factor for venous thromboembolism in humans. We conducted a sensitized N -ethyl- N -nitrosourea (ENU) mutagenesis screen for dominant thrombosuppressor genes based on perinatal lethal thrombosis in mice homozygous for F5 L ( F5 L/L ) and haploinsufficient for tissue factor pathway inhibitor ( Tfpi +/- ). F8 deficiency enhanced the survival of F5 L/L Tfpi +/- mice, demonstrating that F5 L/L Tfpi +/- lethality is genetically suppressible. ENU-mutagenized F5 L/L males and F5 L/+ Tfpi +/- females were crossed to generate 6,729 progeny, with 98 F5 L/L Tfpi +/- offspring surviving until weaning. Sixteen lines, referred to as "modifier of Factor 5 Leiden ( MF5L1-16 )," exhibited transmission of a putative thrombosuppressor to subsequent generations. Linkage analysis in MF5L6 identified a chromosome 3 locus containing the tissue factor gene ( F3 ). Although no ENU-induced F3 mutation was identified, haploinsufficiency for F3 ( F3 +/- ) suppressed F5 L/L Tfpi +/- lethality. Whole-exome sequencing in MF5L12 identified an Actr2 gene point mutation (p.R258G) as the sole candidate. Inheritance of this variant is associated with suppression of F5 L/L Tfpi +/- lethality ( P = 1.7 × 10 -6 ), suggesting that Actr2 p.R258G is thrombosuppressive. CRISPR/Cas9 experiments to generate an independent Actr2 knockin/knockout demonstrated that Actr2 haploinsufficiency is lethal, supporting a hypomorphic or gain-of-function mechanism of action for Actr2 p.R258G Our findings identify F8 and the Tfpi/F3 axis as key regulators in determining thrombosis balance in the setting of F5 L and also suggest a role for Actr2 in this process.

CHARACTERIZATION OF ENU-INDUCED MUTATIONS IN RED BLOOD CELL STRUCTURAL PROTEINS

Directory of Open Access Journals (Sweden)

Katrina Kildey

2013-03-01

Full Text Available Murine models with modified gene function as a result of N-ethyl-N-nitrosourea (ENU mutagenesis have been used to study phenotypes resulting from genetic change. This study investigated genetic factors associated with red blood cell (RBC physiology and structural integrity that may impact on blood component storage and transfusion outcome. Forward and reverse genetic approaches were employed with pedigrees of ENU-treated mice using a homozygous recessive breeding strategy. In a “forward genetic” approach, pedigree selection was based upon identification of an altered phenotype followed by exome sequencing to identify a causative mutation. In a second strategy, a “reverse genetic” approach based on selection of pedigrees with mutations in genes of interest was utilised and, following breeding to homozygosity, phenotype assessed. Thirty-three pedigrees were screened by the forward genetic approach. One pedigree demonstrated reticulocytosis, microcytic anaemia and thrombocytosis. Exome sequencing revealed a novel single nucleotide variation (SNV in Ank1 encoding the RBC structural protein ankyrin-1 and the pedigree was designated Ank1EX34. The reticulocytosis and microcytic anaemia observed in the Ank1EX34 pedigree were similar to clinical features of hereditary spherocytosis in humans. For the reverse genetic approach three pedigrees with different point mutations in Spnb1 encoding RBC protein spectrin-1β, and one pedigree with a mutation in Epb4.1, encoding band 4.1 were selected for study. When bred to homozygosity two of the spectrin-1β pedigrees (a, b demonstrated increased RBC count, haemoglobin (Hb and haematocrit (HCT. The third Spnb1 mutation (spectrin-1β c and mutation in Epb4.1 (band 4.1 did not significantly affect the haematological phenotype, despite these two mutations having a PolyPhen score predicting the mutation may be damaging. Exome sequencing allows rapid identification of causative mutations and development of

A novel ENU-mutation in ankyrin-1 disrupts malaria parasite maturation in red blood cells of mice.

Directory of Open Access Journals (Sweden)

Andreas Greth

Full Text Available The blood stage of the plasmodium parasite life cycle is responsible for the clinical symptoms of malaria. Epidemiological studies have identified coincidental malarial endemicity and multiple red blood cell (RBC disorders. Many RBC disorders result from mutations in genes encoding cytoskeletal proteins and these are associated with increased protection against malarial infections. However the mechanisms underpinning these genetic, host responses remain obscure. We have performed an N-ethyl-N-nitrosourea (ENU mutagenesis screen and have identified a novel dominant (haploinsufficient mutation in the Ank-1 gene (Ank1(MRI23420 of mice displaying hereditary spherocytosis (HS. Female mice, heterozygous for the Ank-1 mutation showed increased survival to infection by Plasmodium chabaudi adami DS with a concomitant 30% decrease in parasitemia compared to wild-type, isogenic mice (wt. A comparative in vivo red cell invasion and parasite growth assay showed a RBC-autonomous effect characterised by decreased proportion of infected heterozygous RBCs. Within approximately 6-8 hours post-invasion, TUNEL staining of intraerythrocytic parasites, showed a significant increase in dead parasites in heterozygotes. This was especially notable at the ring and trophozoite stages in the blood of infected heterozygous mutant mice compared to wt (p<0.05. We conclude that increased malaria resistance due to ankyrin-1 deficiency is caused by the intraerythrocytic death of P. chabaudi parasites.

New cysteamine (2-chloroethyl)nitrosoureas. Synthesis and preliminary antitumor results.

Science.gov (United States)

Madelmont, J C; Godeneche, D; Parry, D; Duprat, J; Chabard, J L; Plagne, R; Mathe, G; Meyniel, G

1985-09-01

Three chemical pathways were used for the synthesis of four new N'-(2-chloroethyl)-N-[2-(methylsulfinyl)ethyl]- and N'-(2-chloroethyl)-N-[2-(methylsulfonyl)ethyl]-N- or N'-nitrosoureas. These compounds are plasma metabolites of CNCC, a promising antineoplastic (2-chloroethyl)nitrosourea. Preliminary antitumor evaluation was performed against L1210 leukemia implanted intraperitoneally in mice. Among these compounds, two of them exhibited a greater antitumor activity compared to that of the parent mixture.

Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002

Energy Technology Data Exchange (ETDEWEB)

Nadeau, Joseph H

2002-07-25

The goal of the conference is to enhance the development of improved technologies and new approaches to the identification of genes underlying chemically-induced mutant phenotypes. The conference brings together ENU mutagenesis experts from the United States and aborad for a small, intensive workshop to consider these issues.

Cytostatic action of two nitrosoureas derived from cysteamine.

Science.gov (United States)

Bourut, C.; Chenu, E.; Godenèche, D.; Madelmont, J. C.; Maral, R.; Mathé, G.; Meyniel, G.

1986-01-01

2-Chloroethyl nitrosocarbamoylcystamine or ICIG-1325 (CNCC) is a lipid-soluble isomeric mixture of nitrosoureas. Its dose-effect relationship on L1210 leukaemia is characterized by a large maximally efficient dose-range (MEDR), greater than that of other nitrosoureas. CNCC also demonstrated significant therapeutic activity on intracerebrally (i.c.) transplanted L1210 leukaemia and on six transplanted solid tumours, TM2 mammary carcinoma, M555 ovarian carcinoma, B16 melanoma, glioma 26, 3LL, Lewis lung carcinoma and colon 26 carcinoma. It was inactive on fibrosarcoma ICIG-Ci4. Its antitumour activity spectrum is wider than that of the related compounds 2-[3-(2-chloroethyl) 3-nitrosoureido]D-glucopyranose (CZT), (chloro-2-ethyl)-1(ribofuranosyl-isopropylidene-2'-3' paranitrobenzoate-5')-3 nitrosourea (RFCNU), and (chloro-2-ethyl)-1 (ribopyranosyl triacetate-2'-3'-4')-3 nitrosourea (RPCNU). A study of its metabolic disposition in animals has shown that CNCC undergoes extensive first-pass metabolism leading to the formation of four main plasma metabolites. These metabolites are water-soluble nitrosoureas that arose from the bioreduction of the disulphide bridge followed by the methylation and the oxidation of the thiol groups. Experimental screening was performed with these chemically synthesized metabolites. Both N'-(2-chloroethyl)-N-[2-(methylsulphinyl)ethyl]-N'-nitrosourea (CMSOEN2) and N'-(2-chloroethyl)-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea (CMSO2EN2) are very active on L1210 leukaemia grafted intraperitoneally (i.p.) and i.c., L40 leukaemia, B16 melanoma, glioma 26 and Lewis lung carcinoma. Their effectiveness is better than that of the parent compound CNCC. In addition,the percentage of mice cured after CMSOEN2 or CMSO2EN2 treatment is increased especially on B16 melanoma and glioma 26.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3801787

Comparative studies of dose-response curves for recessive lethal mutations induced by ethylnitrosourea in spermatogonia and in spermatozoa of Drosophila melanogaster

Energy Technology Data Exchange (ETDEWEB)

Yoshikawa, I.; Ayaki, T.; Ohshima, K.

1984-01-01

Induction of recessive lethal mutation by N-ethyl-N-nitrosourea (ENU) was studied for the second chromosome of spermatogonia and spermatozoa in Drosophila melanogaster. ENU (0.03, 0.3, and 1.0 mM) was given to flies by dissolving it in feeding sucrose solution. When plotted against absorbed doses of ENU, the observed frequencies to recessive lethals showed a linear relationship for induction in spermatozoa but a sigmoidal relationship for induction in spermatogonia. These results suggest that in spermatogonia ENU-induced mutational damage is more repairable in a lower dose range of ENU. Mosaic lethal mutations were induced by ENU but not in spermatogonia.

Ethyl methanesulfonate mutagenesis in Schizosaccharomyces pombe

DEFF Research Database (Denmark)

Ekwall, Karl; Thon, Genevieve

2017-01-01

Here we provide an ethyl methanesulfonate (EMS) mutagenesis protocol for Schizosaccharomyces pombe cells.......Here we provide an ethyl methanesulfonate (EMS) mutagenesis protocol for Schizosaccharomyces pombe cells....

Studies on synthesis and anticancer activity of selected N-(2-fluoroethyl)-N-nitrosoureas.

Science.gov (United States)

Johnston, T P; Kussner, C L; Carter, R L; Frye, J L; Lomax, N R; Plowman, J; Narayanan, V L

1984-11-01

An activated carbamate, 2-nitrophenyl (2-fluoroethyl)nitrosocarbamate (3), was used to advantage in the synthesis of the water-soluble (2-fluoroethyl)nitrosoureas 6a--d from 2-aminoethanol, (1 alpha, 2 beta, 3 alpha)-2-amino-1,3-cyclohexanediol, cis-2-hydroxycyclohexanol, and 2-amino-2-deoxy-D-glucose. In a variation of this method, 2,4,5-trichlorophenyl (2-fluoroethyl)carbamate (4) was used to prepare the urea from which the essentially water-insoluble N-(2,6-dioxo-3-piperidinyl)-N-(2-fluoroethyl)-N-nitrosourea (6e) was derived. The anticancer activity of these nitrosoureas was determined against the murine tumors B16 melanoma and Lewis lung carcinoma and found to be significant and comparable to their chloroethyl counterparts. On the basis of results from both systems, the dihydroxycyclohexyl derivative 6b may be the most effective.

Mutagenic effect of radionuclides incorporated into DNA of Drosophila melanogaster. Progress report, December 15, 1982-July 15, 1983

International Nuclear Information System (INIS)

Lee, W.R.

1983-01-01

The molecular changes in DNA of mutations induced at the well-defined locus alcohol dehydrogenase (Adh) in Drosophila melanogaster were compared between null mutants induced by x-rays, the alkylating agent N-ethyl-N-nitrosourea (ENU) and decay of tritium incorporated into specific sites of DNA

Novel ENU-Induced Mutation in Tbx6 Causes Dominant Spondylocostal Dysostosis-Like Vertebral Malformations in the Rat.

Science.gov (United States)

Abe, Koichiro; Takamatsu, Nobuhiko; Ishikawa, Kumiko; Tsurumi, Toshiko; Tanimoto, Sho; Sakurai, Yukina; Lisse, Thomas S; Lisse, Thomas; Imai, Kenji; Serikawa, Tadao; Mashimo, Tomoji

2015-01-01

Congenital vertebral malformations caused by embryonic segmentation defects are relatively common in humans and domestic animals. Although reverse genetics approaches in mice have provided information on the molecular mechanisms of embryonic somite segmentation, hypothesis-driven approaches cannot adequately reflect human dysmorphology within the population. In a N-ethyl-N-nitrosourea (ENU) mutagenesis project in Kyoto, the Oune mutant rat strain was isolated due to a short and kinked caudal vertebra phenotype. Skeletal staining of heterozygous rats showed partial loss of the cervical vertebrae as well as hemivertebrae and fused vertebral blocks in lumbar and sacral vertebrae. In homozygous embryos, severe displacement of the whole vertebrae was observed. The Oune locus was genetically mapped to rat chromosome 1 using 202 backcross animals and 50 genome-wide microsatellite markers. Subsequently, a miss-sense mutation in the Tbx6 gene was identified in the critical region. Although the mutation is located within the T-box domain near a predicted dimmer-interface, in vitro experiments revealed that the Tbx6 variant retains normal DNA binding ability and translational efficiency. However, the variant has decreased transcriptional activation potential in response to Notch-mediated signaling. Recently, it was reported that a dominant type of familial spondylocostal dysostosis is caused by a stoploss mutation in TBX6. Thus, we propose that partial dysfunction of Tbx6 leads to similar congenital vertebral malformations in both humans and rats. The Oune strain could be a unique animal model for dominant spondylocostal dysostosis and is useful for molecular dissection of the pathology of congenital vertebral malformations in humans.

Novel ENU-Induced Mutation in Tbx6 Causes Dominant Spondylocostal Dysostosis-Like Vertebral Malformations in the Rat.

Directory of Open Access Journals (Sweden)

Koichiro Abe

Full Text Available Congenital vertebral malformations caused by embryonic segmentation defects are relatively common in humans and domestic animals. Although reverse genetics approaches in mice have provided information on the molecular mechanisms of embryonic somite segmentation, hypothesis-driven approaches cannot adequately reflect human dysmorphology within the population. In a N-ethyl-N-nitrosourea (ENU mutagenesis project in Kyoto, the Oune mutant rat strain was isolated due to a short and kinked caudal vertebra phenotype. Skeletal staining of heterozygous rats showed partial loss of the cervical vertebrae as well as hemivertebrae and fused vertebral blocks in lumbar and sacral vertebrae. In homozygous embryos, severe displacement of the whole vertebrae was observed. The Oune locus was genetically mapped to rat chromosome 1 using 202 backcross animals and 50 genome-wide microsatellite markers. Subsequently, a miss-sense mutation in the Tbx6 gene was identified in the critical region. Although the mutation is located within the T-box domain near a predicted dimmer-interface, in vitro experiments revealed that the Tbx6 variant retains normal DNA binding ability and translational efficiency. However, the variant has decreased transcriptional activation potential in response to Notch-mediated signaling. Recently, it was reported that a dominant type of familial spondylocostal dysostosis is caused by a stoploss mutation in TBX6. Thus, we propose that partial dysfunction of Tbx6 leads to similar congenital vertebral malformations in both humans and rats. The Oune strain could be a unique animal model for dominant spondylocostal dysostosis and is useful for molecular dissection of the pathology of congenital vertebral malformations in humans.

Low-dose radiation attenuates chemical mutagenesis in vivo. Cross adaptation

International Nuclear Information System (INIS)

Kakinuma, Shizuko; Yamauchi, Kazumi; Amasaki, Yoshiko; Nishimura, Mayumi; Shimada, Yoshiya

2009-01-01

The biological effects of low-dose radiation are not only of social concern but also of scientific interest. The radioadaptive response, which is defined as an increased radioresistance by prior exposure to low-dose radiation, has been extensively studied both in vitro and in vivo. Here we briefly review the radioadaptive response with respect to mutagenesis, survival rate, and carcinogenesis in vivo, and introduce our recent findings of cross adaptation in mouse thymic cells, that is, the suppressive effect of repeated low-dose radiation on mutation induction by the alkylating agent N-ethyl-N-nitrosourea. (author)

Breeding a PKU-mouse model on Phe-free diet, is it possible?

DEFF Research Database (Denmark)

Dagnæs-Hansen, Frederik; Johansen, Karen Singers; Vorup-Jensen, Thomas

2014-01-01

The PKU-mouse model mutated in the PAH gene was developed in the 1990s in the laboratory of Dr. Alexandra Shedlovsky at the McArdle Laboratory for Cancer Research, University of Wisconsin. The mutation was generated by ENU (N-ethyl-N-nitrosourea) treatment of BTBR males. Several mutation was found...

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo; Reparabilidad durante G1 de las lesiones inductoras de intercambios en las cromatidas hermanas inducidos por agentes alquilantes en ADN sustituido y no sustituido con BrdU, en celulas de la glandula salival de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Gonzalez B, F

2004-07-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo

International Nuclear Information System (INIS)

Gonzalez B, F.

2004-01-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

Effect of DNA sequence, ionic strength, and cationic DNA affinity binders on the methylation of DNA by N-methyl-N-nitrosourea

International Nuclear Information System (INIS)

Wurdeman, R.L.; Gold, B.

1988-01-01

DNA alkylation by N-alkyl-N-nitrosoureas is generally accepted to be responsible for their mutagenic, carcinogenic, and antineoplastic activities. The exact nature of the ultimate alkylating intermediate is still controversial, with a variety of species having been nominated. The sequence specificity for DNA alkylation by simple N-alkyl-N-nitrosoureas has not been reported, although such information is basic in understanding the specific point mutations induced by these compounds in oncogene targets. These two points are addressed by using N-methyl-N-nitrosourea methylation of a 576 base-pair 32 P-end-labeled DNA restriction fragment and high-resolution polyacrylamide sequencing gels. This method provides information on the formation of N 7 -methylguanine, by the generation of single-strand breaks upon exposure to piperidine

Synthesis of [2-13C, 2-14C] 2-aminoethanol, [1-13C, 1-14C] 2-chloroethylamine, N,N'-bis([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(BCNU) and N-([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(CNU)

International Nuclear Information System (INIS)

Narayan, R.; Chang, C-j.

1982-01-01

[2- 13 C, 2- 14 C]2-Aminoethanol hydrochloride was prepared in good yield from Na*CN in a two step sequence by first converting the Na*CN to OHCH 2 *CN and then reducing the nitrile directly with a solution of borane-tetrahydrofuran complex. The reaction procedure was simple and the pure product could be obtained readily. Using this specifically labelled precursor, the synthesis of [1- 13 C, 1- 14 C]2-chloroethylamine hydrochloride, N-([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(CNU) and N,N'-bis([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(BCNU) in good yield without isotope scrambling was also reported. (author)

Enhanced susceptibility of a transposable-element-bearing strain of Drosophila melanogaster to somatic eye-color mutations by ethyl nitrosourea, methyl nitrosourea, and X-rays

International Nuclear Information System (INIS)

Ryo, H.; Kondo, S.; Rasmuson, B.

1983-01-01

A strain of Drosophila with the genes z and w + plus a transposable element (TE) is about 3 times more sensitive than a strain without TE toward somatic eye-color mutations after larval exposure to ethyl nitrosourea, methyl nitrosourea and X-rays. The assay system with TE is simple, reliable, and sensitive for detecting somatic mutations induced in vivo by mutagens. (orig.)

Alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to SCE induction in Chinese hamster V 79-E cells.

Science.gov (United States)

Mendel, J; Thust, R; Schwarz, H

1982-01-01

The alkylating activity, chemical stability in aqueous solution (pH 7.0; 37 degrees C), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1-isopropyl-3-phenyl-1-nitrosourea (i-PrPNU), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (F-MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (Cl-MPNU), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (Br-MPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU), and 1-methyl-3-naphthyl-1-nitrosocarbamate (NCA). 1-Methyl-1-nitrosourea (MNU) and 1-ethyl-1-nitrosourea (ENU) were used for the comparison. THe rate of decomposition in aqueous solution is discussed concerning the influences of the substituents at the 1- and 3-N-atom. The mono- and disubstituted N-nitrosoureas showed a coarse correlation between alkylating activity and SCE induction in Chinese hamster V 79-E cells. On the other hand, this correlation is missing in the case of NCA, which is a potent SCE inducer despite relatively low alkylating activity. DMPNU is the strongest SCE inducer, but this compound shows a high stability in aqueous solution and, consequently, we were not able to detect an alkylating activity.

[The biochemical mechanisms of the action of N-alkyl-N-nitrosoureas. The possible reasons for drug resistance to these compounds].

Science.gov (United States)

Syrkin, A B; Gorbacheva, L B

1996-01-01

N-alkyl-N-nitrosoureas exhibit a wide spectrum of antitumor activity. They react as alkylating agents at nucleophilic sites in purine and pyrimidine moieties of DNA. The predominant site of this alkylation is N7 of guanine, which is followed by the site N3 of adenine and 06 of guanine. The formation and persistence of 0(6)-alkylguanine (0(6)-AG) may be of primary importance in cytotoxicity of the nitrosoureas. 0(6)-AG adducts of DNA of the tumor cells are repaired by protein 0(6)-alkylguanine-DNA transferase (0(6)-AGT) which transfers the alkyl group to internal cysteine residue being the acceptor protein for the alkyl group in an irreversible transfer reaction. 0(6)-AGT can protect the tumor cells against 0(6)-AG adducts by the way of inhibiting the formation of the DNA interstrand cross-links 0(6)-AGT plays an important role in the drug resistance because it repairs the DNA alkyl adducts at the 0(6) position of guanine. The 0(6)-AGT activity inversely correlates with the cytotoxic effect of the nitrosoureas. The agents like 0(6)-methylguanosine, 0(6)-methyl-2'-deoxyguanosine, and some 0(6)-benzylated guanine derivatives are effective inactivators of 0(6)-AGT, and thus can be used to enhance the cytotoxicity of N-nitrosoureas. The activation of 0(6)-AGT and other repairing enzymes such as alpha and beta DNA-polymerases as well as an increase in the level of reduced glutathione may be used in developing the resistance to the nitrosoureas.

Assessment of mutagenic damage by monofunctional alkylating agents and gamma radiation in haploid and diploid frogs, Xenopus laevis

International Nuclear Information System (INIS)

Hart, D.R.; Armstrong, J.B.

1984-01-01

Adult male South African clawed frogs, Xenopus laevis, were mutagenized by 3-day immersion in aqueous solutions of ethyl methanesulfonate (EMS), diethyl nitrosamine (DEN), or ethyl nitrosourea (ENU), or by acute exposure to gamma radiation. They were then spawned repeatedly at 2-week intervals with untreated females, and embryonic survival of the progeny was used to assess genetic damage. Recessive lethal effects were assessed from reduced survival of androgenetic haploid progeny. Neither recessive nor dominant lethal effects were obtained after exposure to 100 mg/liter EMS or 2 g/liter DEN. At 250 mg/liter EMS, peak dominant lethality occurred 3-5 weeks after treatment. Most embryos hatched, but many were abnormal and died shortly after hatching. Haploid survival was significantly reduced over a broader period, from 1 to 13 weeks after mutagenesis. Treatment with 75 mg/liter ENU produced effects similar to the 250-mg/liter EMS mutagenesis. At 400 mg/liter EMS, the frequency and severity of the effects on both diploid and haploid embryos were increased over the lower dose. Gamma irradiation at 1500 R produced effects similar to the 400-mg/liter mutagenesis, except that peak dominant lethality extended from 1 to 7 weeks

Investigation of J-shaped dose-responses induced by exposure to the alkylating agent N-methyl-N-nitrosourea.

Science.gov (United States)

Chapman, Katherine E; Hoffmann, George R; Doak, Shareen H; Jenkins, Gareth J S

2017-07-01

Hormesis is defined as a biphasic dose-response where biological effects of low doses of a stressor demonstrate the opposite effect to high-dose effects of the same stressor. Hormetic, or J-shaped, dose-response relationships are relatively rarely observed in toxicology, resulting in a limited understanding and even some skepticism of the concept. Low dose-response studies for genotoxicity endpoints have been performed at Swansea University for over a decade. However, no statistically significant decreases below control genotoxicity levels have been detected until recently. A hormetic-style dose-response following a 24h exposure to the alkylating agent N-methyl-N-nitrosourea (MNU) was observed in a previous study for HPRT mutagenesis in the human lymphoblastoid cell line AHH-1. A second recent study demonstrated a J-shaped dose-response for the induction of micronuclei by MNU in a 24h treatment in a similar test system. Following mechanistic investigations, it was hypothesized that p53 may be responsible for the observed hormetic phenomenon. As genotoxic carcinogens are a major causative factor of many cancers, consideration of hormesis in carcinogenesis could be important in safety assessment. The data examined here offer possible insights into hormesis, including its estimated prevalence, underlying mechanisms and lack of generalizability. Copyright © 2017 Elsevier B.V. All rights reserved.

The involvement of poly(ADP-ribose) polymerase in the degradation of NAD caused by γ-radiation and N-methyl-N-nitrosourea

International Nuclear Information System (INIS)

Skidmore, C.J.; Davies, M.I.; Goodwin, P.M.; Halldorsson, H.; Lewis, P.J.; Shall, S.; Zia'ee, A.

1979-01-01

Both N-methyl-N-nitrosourea and γ-radiation lower cellular NAD in mouse leukaemia cells (L1210) in a dose-dependent way. The minimum NAD level is reached 2 h after a brief exposure to N-methyl-N-nitrosourea, but within 15 min of γ-irradiation. The cells remain metabolically active; they are able to recover their control NAD levels and are impermeable to trypan blue. Several inhibitors of poly(ADP-ribose) polymerase inhibit the drop in cellular NAD caused by these two agents: 2 mM 5-methylnicotinamide, 1 mM theophylline or 1 mM theobromine inhibit the effect of N-methyl-N-nitrosourea on cellular NAD level; 200 μM thymidine, 500 μM 5-methylnicotinaminde, 500 μM thephylline and 500 μM theobromine prevent the lowering of cellular NAD by γ-irradiation. The extent to which the drop in cellular NAD is inhibited is dependent on both the concentration of cytotoxic agent and of polymerase inhibitor. Caffeine will inhibit the drop in NAD but only at 10 mM, while nicotonic acid is ineffictive even at this dose. The activity of poly(ADP-ribose) polymerase is permeabilized cells immediately after γ-radiation increases with dose up to 12 krad, giving a maximal 3.4-fold stimulation of the enzyme activity, whereas the degradation of NAD under conditions optimal for NAD glycohydrolase does not change. The activity of the polymerase shows a close temporal correlation with the NAD drop following both γ-radiation and N-methyl-N-nitrosourea. The enzyme activity is maximal when the NAD content. (orig./AJ) 891 AJ/orig.- 892 HIS [de

Modifier action of the chlorophyllin of the mutagenesis induced by the ethyl-nitroso-urea (ENU) in germinal cells of Drosophila melanogaster

International Nuclear Information System (INIS)

Morales N, I.

2006-01-01

The cupro-sodium chlorophyllin (CCS) it is a soluble porphyrin in water that it includes in its it structures a copper atom instead of the magnesium that has the chlorophyll. Diverse experiments have demonstrated that it possesses a potent activity, reducing or inhibiting, the DNA damage caused by physical and chemical agents of direct action or insinuation. Most of the knowledge about their anti genotoxic activity has been obtained using somatic cells of different organisms, on the other hand it is known very little of their effect in germinal cells. At the moment in the Drosophila laboratory of the ININ it is investigating the protective action of the CCS in germinal cells, with these studies has been observed that its administration to females that were crossed with males irradiated with 20 Gy of gamma radiation, promotes the induction of lethal dominant in the embryonic and post-embryonic states causing a diminution in the viability egg-adult. With the test of lethal recessive bound to the sex one has evidence that it increases the basal frequency of lethal recessive and it doesn't reduce those induced by radiation. In contrast, with the present investigation when the CCS was administered to males that later on were treated with ethyl-nitroso-urea (ENU) caused a reduction of the lethal frequency in all the monitored cellular states, but only it was significant in the post-meiotic cells. On the contrary, when the CCS was administered to the female ones and then they crossed with males treaties with ENU, it was observed a tendency to increase the lethal ones in all the cellular types. With both protocols the CCS caused a diminution of the sterility. The fact that the CCS has antagonistic activities, it deserves special attention to investigate with different protocols and systems, the conditions in that this pigment can work as a true antimutagenic and/or anti carcinogenic before being able to him to propose as a chemopreventor. (Author)

A Theoretical Study of the Mechanism of the Alkylation of Guanine by N- Nitroso Compounds.

Science.gov (United States)

1992-01-01

these chemical agents alkylate DNA, but, as yet, the precise mechanism is unknown. What is known is that the result is a DNA-mutagen adduct with an alkyl ... nitrosoureas , Singer et. al. found that about 25% of the alkylation caused by MNU was on the DNA phospate backbone while, for ENU, phosphate...sites. 1.3 Mutagenicity of N-Nitroso Compounds In early experimental work with agents which alkylate DNA, comparisons of ultraviolet absorption

Response of clonogenic cells of mice solid tumour NKLy/LL to N-methyl-N-nitrosourea

International Nuclear Information System (INIS)

Chan Tik Kan; Afanas'ev, G.G.; Pelevina, I.I.

1979-01-01

By cloning in vitro the cells of NKLy/LL solid tumour of mice it has been shown that the curve of clonogenic cell survival versus N-methyl-N-nitrosourea (MNU) dose in the 12.5-200.0 mg/kg interval is exponential and characterized by Dsub(o)=29.15 mg/kg dose value. Large size tumours (15.0-17.0 g) are characterized by higher death rate of clonogenic cells (survivor fraction approximately 0.5%) than in 1.0-7.0 g tumours (survivor fraction 2-4%). That is, evidently, related to higher sensitivity of the resting tumour cells to MNU

Assessment of thermal neutron and N-methyl-N-nitrosourea activities in groups of barley mutants with possible breeding use

International Nuclear Information System (INIS)

Uhlik, J.; Burianova, S.

1982-01-01

During the study of genetic variability induced after the application of thermal neutrons and N-methyl-N-nitrosourea in barley, marked differences were manifest when selected mutated progeny sets with possible breeding use were evaluated. It is recommended on the basis of the results to use separately a chemical mutagen and a physical mutagen for influencing the same material in which it is intended to obtain the largest possible amount of mutated progenies that could be used in breeding. In the set of selected progenies offering the possibility of breeding use, thermal neutrons induced larger proportions of high-tillering progenies, progenies with preference to the first tillers, with longer stalks, with a firm stalk, with one stalk, with an erect ear with deformed spikelets, with ears having deformed first sections, later ripening, with earlier heading time. N-methyl-N-nitrosourea induced larger proportions of progenies with reduced wax production, with broader or narrow blades, with necrosis on leaves, with shorter stalks, with denser ears, with multiple-row ears, with shorter awns, with golden-coloured awns, with medium-early ripening, and with delayed heading time. (author)

Antimutagenic components in Glycyrrhiza against N-methyl-N-nitrosourea in the Ames assay.

Science.gov (United States)

Inami, Keiko; Mine, Yusuke; Kojo, Yukiko; Tanaka, Satomi; Ishikawa, Satoko; Mochizuki, Masataka

2017-03-01

Antimutagenesis against N-nitroso compounds contribute to prevention of human cancer. We have found that Glycyrrhiza aspera ethanolic extract exhibits antimutagenic activity against N-methyl-N-nitrosourea (MNU) using the Ames assay with Salmonella typhimurium TA1535. In the present study, eight purified components from Glycyrrhiza, namely glabridin, glycyrrhetinic acid, glycyrrhizin, licochalcone A, licoricesaponin H2, licoricesaponin G2, liquiritigenin and liquiritin were evaluated for their antimutagenicity against MNU in the Ames assay with S. typhimurium TA1535. Glycyrrhetinic acid, glycyrrhizin, licoricesaponin G2, licoricesaponin H2 and liquiritin did not show the antimutagenicity against MNU in S. typhimurium TA1535. Glabridin, licochalcone A and liquiritigenin reduced revertant colonies derived from MNU in S. typhimurium TA1535 without showing cytotoxic effects, indicating that these compounds possess antimutagenic activity against MNU. The inhibitory activity of glabridin and licochalcone A was more effective than that of liquiritigenin. Thus, Glycyrrhiza contains antimutagenic components against DNA alkylating, direct-acting carcinogens.

Sequence distribution of acetaldehyde-derived N2-ethyl-dG adducts along duplex DNA.

Science.gov (United States)

Matter, Brock; Guza, Rebecca; Zhao, Jianwei; Li, Zhong-ze; Jones, Roger; Tretyakova, Natalia

2007-10-01

Acetaldehyde (AA) is the major metabolite of ethanol and may be responsible for an increased gastrointestinal cancer risk associated with alcohol beverage consumption. Furthermore, AA is one of the most abundant carcinogens in tobacco smoke and induces tumors of the respiratory tract in laboratory animals. AA binding to DNA induces Schiff base adducts at the exocyclic amino group of dG, N2-ethylidene-dG, which are reversible on the nucleoside level but can be stabilized by reduction to N2-ethyl-dG. Mutagenesis studies in the HPRT reporter gene and in the p53 tumor suppressor gene have revealed the ability of AA to induce G-->A transitions and A-->T transversions, as well as frameshift and splice mutations. AA-induced point mutations are most prominent at 5'-AGG-3' trinucleotides, possibly a result of sequence specific adduct formation, mispairing, and/or repair. However, DNA sequence preferences for the formation of acetaldehyde adducts have not been previously examined. In the present work, we employed a stable isotope labeling-HPLC-ESI+-MS/MS approach developed in our laboratory to analyze the distribution of acetaldehyde-derived N2-ethyl-dG adducts along double-stranded oligodeoxynucleotides representing two prominent lung cancer mutational "hotspots" and their surrounding DNA sequences. 1,7,NH 2-(15)N-2-(13)C-dG was placed at defined positions within DNA duplexes derived from the K-ras protooncogene and the p53 tumor suppressor gene, followed by AA treatment and NaBH 3CN reduction to convert N2-ethylidene-dG to N2-ethyl-dG. Capillary HPLC-ESI+-MS/MS was used to quantify N2-ethyl-dG adducts originating from the isotopically labeled and unlabeled guanine nucleobases and to map adduct formation along DNA duplexes. We found that the formation of N2-ethyl-dG adducts was only weakly affected by the local sequence context and was slightly increased in the presence of 5-methylcytosine within CG dinucleotides. These results are in contrast with sequence

ENU-mutagenesis mice with a non-synonymous mutation in Grin1 exhibit abnormal anxiety-like behaviors, impaired fear memory, and decreased acoustic startle response

Science.gov (United States)

2013-01-01

Background The Grin1 (glutamate receptor, ionotropic, NMDA1) gene expresses a subunit of N-methyl-D-aspartate (NMDA) receptors that is considered to play an important role in excitatory neurotransmission, synaptic plasticity, and brain development. Grin1 is a candidate susceptibility gene for neuropsychiatric disorders, including schizophrenia, bipolar disorder, and attention deficit/hyperactivity disorder (ADHD). In our previous study, we examined an N-ethyl-N-nitrosourea (ENU)-generated mutant mouse strain (Grin1Rgsc174/Grin1+) that has a non-synonymous mutation in Grin1. These mutant mice showed hyperactivity, increased novelty-seeking to objects, and abnormal social interactions. Therefore, Grin1Rgsc174/Grin1+ mice may serve as a potential animal model of neuropsychiatric disorders. However, other behavioral characteristics related to these disorders, such as working memory function and sensorimotor gating, have not been fully explored in these mutant mice. In this study, to further investigate the behavioral phenotypes of Grin1Rgsc174/Grin1+ mice, we subjected them to a comprehensive battery of behavioral tests. Results There was no significant difference in nociception between Grin1Rgsc174/Grin1+ and wild-type mice. The mutants did not display any abnormalities in the Porsolt forced swim and tail suspension tests. We confirmed the previous observations that the locomotor activity of these mutant mice increased in the open field and home cage activity tests. They displayed abnormal anxiety-like behaviors in the light/dark transition and the elevated plus maze tests. Both contextual and cued fear memory were severely deficient in the fear conditioning test. The mutant mice exhibited slightly impaired working memory in the eight-arm radial maze test. The startle amplitude was markedly decreased in Grin1Rgsc174/Grin1+ mice, whereas no significant differences between genotypes were detected in the prepulse inhibition (PPI) test. The mutant mice showed no obvious

Novel gene function revealed by mouse mutagenesis screens for models of age-related disease.

Science.gov (United States)

Potter, Paul K; Bowl, Michael R; Jeyarajan, Prashanthini; Wisby, Laura; Blease, Andrew; Goldsworthy, Michelle E; Simon, Michelle M; Greenaway, Simon; Michel, Vincent; Barnard, Alun; Aguilar, Carlos; Agnew, Thomas; Banks, Gareth; Blake, Andrew; Chessum, Lauren; Dorning, Joanne; Falcone, Sara; Goosey, Laurence; Harris, Shelley; Haynes, Andy; Heise, Ines; Hillier, Rosie; Hough, Tertius; Hoslin, Angela; Hutchison, Marie; King, Ruairidh; Kumar, Saumya; Lad, Heena V; Law, Gemma; MacLaren, Robert E; Morse, Susan; Nicol, Thomas; Parker, Andrew; Pickford, Karen; Sethi, Siddharth; Starbuck, Becky; Stelma, Femke; Cheeseman, Michael; Cross, Sally H; Foster, Russell G; Jackson, Ian J; Peirson, Stuart N; Thakker, Rajesh V; Vincent, Tonia; Scudamore, Cheryl; Wells, Sara; El-Amraoui, Aziz; Petit, Christine; Acevedo-Arozena, Abraham; Nolan, Patrick M; Cox, Roger; Mallon, Anne-Marie; Brown, Steve D M

2016-08-18

Determining the genetic bases of age-related disease remains a major challenge requiring a spectrum of approaches from human and clinical genetics to the utilization of model organism studies. Here we report a large-scale genetic screen in mice employing a phenotype-driven discovery platform to identify mutations resulting in age-related disease, both late-onset and progressive. We have utilized N-ethyl-N-nitrosourea mutagenesis to generate pedigrees of mutagenized mice that were subject to recurrent screens for mutant phenotypes as the mice aged. In total, we identify 105 distinct mutant lines from 157 pedigrees analysed, out of which 27 are late-onset phenotypes across a range of physiological systems. Using whole-genome sequencing we uncover the underlying genes for 44 of these mutant phenotypes, including 12 late-onset phenotypes. These genes reveal a number of novel pathways involved with age-related disease. We illustrate our findings by the recovery and characterization of a novel mouse model of age-related hearing loss.

Chemical carcinogenesis in the nervous system. Preferential accumulation of O6-methylguanine in rat brain deoxyribonucleic acid during repetitive administration of N-methyl-N-nitrosourea.

Science.gov (United States)

Margison, G P; Kleihues, P

1975-01-01

The alkylation of purine bases in DNA of several rat tissues was determined during weekly injections (10 mg/kg) of N-[3H]methyl-N-nitrosourea, a dose schedule known to selectively induce tumours of the nervous system. Each group of animals was killed 1 week after the final injection, and the DNA hydrolysates were analysed by chromatography on Sephadex G-10. After five weekly applications, O6-methylguanine had accumulated in brain DNA to an extent which greatly exceeded that in kidney, spleen and intestine. In the liver, the final O6-methylguanine concentration was less than 1% of that in brain. Between the first and the fifth injection, the O6-methylguanine/7-methylguanine ratio in cerebral DNA increased from 0.28 to 0.68. In addition, 3-methylguanine was found to accumulate in brain DNA whereas in the other organs no significant quantities of this base were detectable. The results are compatible with the hypothesis that O6-alkylation of guanine in DNA plays a major role in the induction of tumours by N-methyl-N-nitrosourea and related carcinogens. The kinetics of the increase of O6-methylguanine in cerebral DNA suggest that there is no major cell fraction in the brain which is capable of excising chemically methylated bases from DNA. This repair deficiency could be a determining factor in the selective induction of nervous-system tumours by N-methyl-N-nitrosourea and other neuro-oncogenic compounds. PMID:1200992

Modifier action of the chlorophyllin of the mutagenesis induced by the ethyl-nitroso-urea (ENU) in germinal cells of Drosophila melanogaster; Accion modificadora de la clorofilina de la mutagenesis inducida por la etil-nitroso-urea (ENU) en celulas germinales de Drosophila melanogaster

Energy Technology Data Exchange (ETDEWEB)

Morales N, I

2006-07-01

The cupro-sodium chlorophyllin (CCS) it is a soluble porphyrin in water that it includes in its it structures a copper atom instead of the magnesium that has the chlorophyll. Diverse experiments have demonstrated that it possesses a potent activity, reducing or inhibiting, the DNA damage caused by physical and chemical agents of direct action or insinuation. Most of the knowledge about their anti genotoxic activity has been obtained using somatic cells of different organisms, on the other hand it is known very little of their effect in germinal cells. At the moment in the Drosophila laboratory of the ININ it is investigating the protective action of the CCS in germinal cells, with these studies has been observed that its administration to females that were crossed with males irradiated with 20 Gy of gamma radiation, promotes the induction of lethal dominant in the embryonic and post-embryonic states causing a diminution in the viability egg-adult. With the test of lethal recessive bound to the sex one has evidence that it increases the basal frequency of lethal recessive and it doesn't reduce those induced by radiation. In contrast, with the present investigation when the CCS was administered to males that later on were treated with ethyl-nitroso-urea (ENU) caused a reduction of the lethal frequency in all the monitored cellular states, but only it was significant in the post-meiotic cells. On the contrary, when the CCS was administered to the female ones and then they crossed with males treaties with ENU, it was observed a tendency to increase the lethal ones in all the cellular types. With both protocols the CCS caused a diminution of the sterility. The fact that the CCS has antagonistic activities, it deserves special attention to investigate with different protocols and systems, the conditions in that this pigment can work as a true antimutagenic and/or anti carcinogenic before being able to him to propose as a chemopreventor. (Author)

Sensitivity of Bidens laevis L. to mutagenic compounds. Use of chromosomal aberrations as biomarkers of genotoxicity

Energy Technology Data Exchange (ETDEWEB)

Perez, D.J. [Laboratorio de Genetica, Estacion Experimental Agropecuaria Balcarce (INTA), Facultad de Ciencias Agrarias, UNMdP, CC 276, 7620 Balcarce (Argentina); Laboratorio de Ecotoxicologia, Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, UNMdP, Funes 3350, 7600 Mar del Plata (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina); Lukaszewicz, G. [Laboratorio de Ecotoxicologia, Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, UNMdP, Funes 3350, 7600 Mar del Plata (Argentina); Menone, M.L., E-mail: lujanm@mdp.edu.a [Laboratorio de Ecotoxicologia, Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, UNMdP, Funes 3350, 7600 Mar del Plata (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina); Camadro, E.L. [Laboratorio de Genetica, Estacion Experimental Agropecuaria Balcarce (INTA), Facultad de Ciencias Agrarias, UNMdP, CC 276, 7620 Balcarce (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina)

2011-01-15

The wetland macrophyte Bidens laevis possesses suitable cytological characteristics for genotoxicity testing. To test its sensitivity as compared to terrestrial plants species currently in use in standardized assays, Methyl Methanesulfonate (MMS), N-ethyl-N-nitrosourea (ENU) and Maleic Hydrazide (HM) were used. On the other hand, the insecticide Endosulfan (ES) - an environmentally relevant contaminant - was assayed in seeds and two-month old plants. Mitotic Index (MI), frequency of Chromosome Aberrations in Anaphase-Telophase (CAAT) and frequency of Abnormal Metaphases (AM) were analyzed. MH, MMS and ENU caused a significant decrease of the MI. MMS was aneugenic whereas MH and ENU were both aneugenic and clastogenic. ES caused a significant concentration-dependent increase of total- and aneugenic-CAAT in roots and a significant high frequency of AM at high concentrations. Because of its sensitivity to mutagenic substances, B. laevis can be regarded as a reliable and convenient species for genotoxicity assays especially if aquatic contaminants are evaluated. - The wetland macrophyte Bidens laevis is sensitive to genotoxic compounds similarly to terrestrial standardized species.

Sensitivity of Bidens laevis L. to mutagenic compounds. Use of chromosomal aberrations as biomarkers of genotoxicity

International Nuclear Information System (INIS)

Perez, D.J.; Lukaszewicz, G.; Menone, M.L.; Camadro, E.L.

2011-01-01

The wetland macrophyte Bidens laevis possesses suitable cytological characteristics for genotoxicity testing. To test its sensitivity as compared to terrestrial plants species currently in use in standardized assays, Methyl Methanesulfonate (MMS), N-ethyl-N-nitrosourea (ENU) and Maleic Hydrazide (HM) were used. On the other hand, the insecticide Endosulfan (ES) - an environmentally relevant contaminant - was assayed in seeds and two-month old plants. Mitotic Index (MI), frequency of Chromosome Aberrations in Anaphase-Telophase (CAAT) and frequency of Abnormal Metaphases (AM) were analyzed. MH, MMS and ENU caused a significant decrease of the MI. MMS was aneugenic whereas MH and ENU were both aneugenic and clastogenic. ES caused a significant concentration-dependent increase of total- and aneugenic-CAAT in roots and a significant high frequency of AM at high concentrations. Because of its sensitivity to mutagenic substances, B. laevis can be regarded as a reliable and convenient species for genotoxicity assays especially if aquatic contaminants are evaluated. - The wetland macrophyte Bidens laevis is sensitive to genotoxic compounds similarly to terrestrial standardized species.

Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin.

Directory of Open Access Journals (Sweden)

Melissa K Boles

2009-12-01

Full Text Available An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn, inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing.

21 CFR 176.160 - Chromium (Cr III) complex of N-ethyl-N-heptadecylfluoro-octane sulfonyl glycine.

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2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chromium (Cr III) complex of N-ethyl-N... § 176.160 Chromium (Cr III) complex of N-ethyl-N-heptadecylfluoro-octane sulfonyl glycine. The chromium... by weight of the chromium (Cr III) complex of heptadecylfluoro-octane sulfonic acid may be safely...

Inhibition of mutagenicity of N-methyl-N-nitrosourea by ellagic acid

International Nuclear Information System (INIS)

Dixit, R.; Gold, B.

1986-01-01

Ellagic acid (EA), a plant phenol present in a variety of soft fruits and vegetables, has been shown to possess antimutagenic and anticarcinogenic properties against bay region diol epoxide of polycyclic aromatic hydrocarbons. It is suggested that EA forms an adduct with diol epoxide of benzo (α) pyrene and thus prevents its binding to DNA. To better understand the mechanism of reactivity and inhibition properties of EA, we studied the effect of EA on mutagenicity and DNA alkylation of carcinogenic N-nitroso compounds, including N-methyl-N-nitrosourea (MNU) and N-methyl-N'-nitro-Nnitrosoguanidine (MNNG). MNU and MNNG are direct-acting mutagens requiring no metabolic activation. MNU showed a linear dose response between the concentration range of 50 to 400 nmole in an Ames/Salmonella mammalian mutagenicity test. EA at concentrations of 100, 250, 500, and 1,000 nmole inhibited the mutagenicity of MNU (400 nmole) by 3, 13, 45,and 60%, respectively. MNNG produced a nonlinear dose response in mutagenicity between the concentrations of 0.5 to 4 nmole. EA showed no appreciable inhibition of MNNG mutagenicity. Inhibition of DNA alkylation by MNU and MNNG by EA was studied by preincubating 50 to 200 nmole of EA with 200 nmole of ( 3 H)-MNU or ( 3 H)-MNNG for 10 min at 37 0 c, followed by incubation of polymer deoxyguanosine: deoxycytosine (poly dG:dC) (1 unit) overnight. EA caused no inhibitory effect on MNNG alkylation of poly dG:dC. Experiments on the effect of EA on alkylation of DNA and formation of nucleoside adducts by MNU are in progress, and results will be discussed with reference to MNU and MNNG mutagenicity and EA inhibition

A Rat Model for Human Ductal Carcinoma In Situ

Science.gov (United States)

2006-09-01

nitrosourea (MNU). The cancers were varied in their estrogen and progesterone receptor expression as determined by immunocytochemistry. The objectives...transformed to preneoplastic and neoplastic states with well known mammary carcinogens such as N-methyl-N- nitrosourea (4), N-ethyl- nitrosourea ...methyl-N- nitrosourea or N-ethyl- nitrosourea . Our experimental objectives were to develop methods for the induction of intraductal and intralobular

Study of the rearrangement of N-alkylaniline to p-aminoalkylbencene. I. N-ethyl-l-14C-aniline

International Nuclear Information System (INIS)

Molera, M. J.; Gamboa, J. M.; Val Cob, M. del

1961-01-01

The rearrangement of N-ethylaniline to p-aminoethylbenzene has been studied over the temperature range 200-300 degree centigrade using different catalysts: Cl 2 Co, Cl 2 Zn, Cl 2 Ni, Cl 3 Al, Cl 2 Cd and Br H.N-ethyl-1- 1 4C-aniline has been synthesized from ethyl-1- 1 4C-iodide and aniline and its rearrangement to p-aminoethyl-benzene proves that the ethyl group does not rearrange itself during the reaction. A scheme for the degradation of both the N-ethyl-1- 1 4C aniline and the p-aminoethylbenzene produces is described. (Author) 14 refs

Enu mutagenesis identifies a novel platelet phenotype in a loss-of-function Jak2 allele.

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Nicole M Anderson

Full Text Available Utilizing ENU mutagenesis, we identified a mutant mouse with elevated platelets. Genetic mapping localized the mutation to an interval on chromosome 19 that encodes the Jak2 tyrosine kinase. We identified a A3056T mutation resulting in a premature stop codon within exon 19 of Jak2 (Jak2(K915X, resulting in a protein truncation and functionally inactive enzyme. This novel platelet phenotype was also observed in mice bearing a hemizygous targeted disruption of the Jak2 locus (Jak2(+/-. Timed pregnancy experiments revealed that Jak2(K915X/K915X and Jak2(-/- displayed embryonic lethality; however, Jak2(K915X/K915X embryos were viable an additional two days compared to Jak2(-/- embryos. Our data suggest that perturbing JAK2 activation may have unexpected consequences in elevation of platelet number and correspondingly, important implications for treatment of hematological disorders with constitutive Jak2 activity.

Reduced DNA repair in mouse satellite DNA after treatment with methylmethanesulfonate, and N-methyl-N-nitrosourea.

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Bodell, W J; Banerjee, M R

1976-01-01

We have measured DNA repair in mouse satellite and main band DNA as resolved by Ag+-Cs2SO4 centrifugation in response to treatment with the alkylating agents, methyl methanesulfonate, and N-methyl-N-nitrosourea. We find that there is a statistically significant lower incorporation of 3H-Tdr into the satellite DNA as compared to the main band at varying periods after treatment with the alkylating agents. This suggests a reduced repair activity in the satellite DNA. We have measured the extent of binding of 14C-methyl methanesulfonate to the satellite, and main band DNA, and no difference in binding was observed, indicating that the reduced repair activity of satellite DNA is not due to a difference in binding of alkylating agents. We believe that the reduced incorporation of 3H-Tdr into satellite DNA may be due to its location in the condensed chromatin fraction. PMID:184436

Spin-labeled 1-alkyl-1-nitrosourea synergists of antitumor antibiotics.

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Gadjeva, V; Koldamova, R

2001-01-01

A new method for synthesis of four spin-labeled structural analogues of the antitumor drug 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), using ethyl nitrite for nitrosation of the intermediate spin-labeled ureas has been described. In vitro synergistic effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-1-nitrosourea (3b) on the cytotoxicity of bleomycin and farmorubicin were found in human lymphoid leukemia tumor cells. We measured the tissue distribution of 3b in organ homogenates of C57BL mice by an electron paramagnetic resonance method. The spin-labeled nitrosourea was mainly localized in the lungs. Our results strongly support the development and validation of a new approach for synthesis of less toxic nitrosourea derivatives as potential synergists of antitumor drugs.

Genome-wide comparison of ultraviolet and ethyl methanesulphonate mutagenesis methods for the brown alga Ectocarpus.

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Godfroy, Olivier; Peters, Akira F; Coelho, Susana M; Cock, J Mark

2015-12-01

Ectocarpus has emerged as a model organism for the brown algae and a broad range of genetic and genomic resources are being generated for this species. The aim of the work presented here was to evaluate two mutagenesis protocols based on ultraviolet irradiation and ethyl methanesulphonate treatment using genome resequencing to measure the number, type and distribution of mutations generated by the two methods. Ultraviolet irradiation generated a greater number of genetic lesions than ethyl methanesulphonate treatment, with more than 400 mutations being detected in the genome of the mutagenised individual. This study therefore confirms that the ultraviolet mutagenesis protocol is suitable for approaches that require a high density of mutations, such as saturation mutagenesis or Targeting Induced Local Lesions in Genomes (TILLING). Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid identification and recovery of ENU-induced mutations with next-generation sequencing and Paired-End Low-Error analysis.

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Pan, Luyuan; Shah, Arish N; Phelps, Ian G; Doherty, Dan; Johnson, Eric A; Moens, Cecilia B

2015-02-14

Targeting Induced Local Lesions IN Genomes (TILLING) is a reverse genetics approach to directly identify point mutations in specific genes of interest in genomic DNA from a large chemically mutagenized population. Classical TILLING processes, based on enzymatic detection of mutations in heteroduplex PCR amplicons, are slow and labor intensive. Here we describe a new TILLING strategy in zebrafish using direct next generation sequencing (NGS) of 250 bp amplicons followed by Paired-End Low-Error (PELE) sequence analysis. By pooling a genomic DNA library made from over 9,000 N-ethyl-N-nitrosourea (ENU) mutagenized F1 fish into 32 equal pools of 288 fish, each with a unique Illumina barcode, we reduce the complexity of the template to a level at which we can detect mutations that occur in a single heterozygous fish in the entire library. MiSeq sequencing generates 250 base-pair overlapping paired-end reads, and PELE analysis aligns the overlapping sequences to each other and filters out any imperfect matches, thereby eliminating variants introduced during the sequencing process. We find that this filtering step reduces the number of false positive calls 50-fold without loss of true variant calls. After PELE we were able to validate 61.5% of the mutant calls that occurred at a frequency between 1 mutant call:100 wildtype calls and 1 mutant call:1000 wildtype calls in a pool of 288 fish. We then use high-resolution melt analysis to identify the single heterozygous mutation carrier in the 288-fish pool in which the mutation was identified. Using this NGS-TILLING protocol we validated 28 nonsense or splice site mutations in 20 genes, at a two-fold higher efficiency than using traditional Cel1 screening. We conclude that this approach significantly increases screening efficiency and accuracy at reduced cost and can be applied in a wide range of organisms.

Structure-based design of nitrosoureas containing tyrosine derivatives as potential antimelanoma agents.

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Gadjeva, Vesselina

2002-04-01

Two new nitrosoureas (TNUs), containing tyrosine derivatives as carriers of nitrosourea cytotoxic group have been synthesised. The physicochemical properties such as half-life time (tau(0.5)), alkylating and carbamoylating activities were determined. The nitrosoureas showed a higher inhibiting effect on the DOPA-oxidase activity of mushroom tyrosinase than that of the antitumour drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU). In vitro cytotoxic effects of newly synthesised tyrosine containing nitrosoureas have been studied and compared to those of CCNU. A higher cytotoxicity to B16 melanoma cells than to YAC-1 and to lymphocytes was demonstrated for the tyrosine containing nitrosoureas in comparison with CCNU. Based on the results presented, we accept that a new trend for synthesis of more selective and less toxic nitrosourea derivatives as potential antimelanomic drugs might be developed.

Molecular analysis of mutant and wild type alcohol dehydrogenase alleles from Drosophila

International Nuclear Information System (INIS)

Batzer, M.A.

1988-01-01

Wild type alcohol dehydrogenase polypeptides (ADH) from Drosophila melanogaster transformants were examined using western blots and polyclonal antiserum specific for Drosophila melanogaster ADH. Mutants induced in Drosophila spermatozoa at the alcohol dehydrogenase (Adh) locus using X-rays, 1-ethyl-1-nitrosourea (ENU) or ethyl methanesulfonate (EMS) were characterized using genetic complementation tests, western blots, Southern blots, northern blots and enzymatic amplification of the Adh locus. Genetic complementation tests showed that 22/30 X-ray-induced mutants, and 3/13 ENU and EMS induced mutants were multi-locus deficiencies. Western blot analysis of the intragenic mutations showed that 4/7 X-ray-induced mutants produced detectable polypeptides, one of which was normal in molecular weight and charge. In contrast 8/10 intragenic ENU and EMS induced mutants produced normal polypeptides. Southern blot analysis showed that 5/7 intragenic X-ray induced mutants and all 10 of the intragenic ENU and EMS induced mutants were normal with respect to the alleles they were derived from

Effects of X-irradiation on N-methyl-N-nitrosourea-induced multi-organ carcinogenesis in rats

International Nuclear Information System (INIS)

Morishita, Yukiko; Tanaka, Takuji; Mori, Hideki; Sasaki, Shunsaku.

1993-01-01

The effects of X-irradiation on N-methyl-N-nitrosourea (MNU)-induced multi-organ carcinogenesis were examined in both sexes of ACI/N rats. At 6 weeks of age, rats in groups 1 (25 males, 25 females) and 3 (24 males, 23 females) received a single intraperitoneal injection of MNU (25 mg/kg body weight), while those in groups 2 (25 males, 26 females) and 4 (25 males, 25 females) were administered the carcinogen at a dose of 50 mg/kg body weight. At 10 weeks of age, group 3 and group 4 were X-irradiated at dose of 3 Gy. Group 5 (24 males, 24 females) received X-irradiation alone. Group 6 (21 males, 21 females) served as an untreated control. As a result, neoplasms developed mainly in the digestive tract, kidney, uterus, and hematopoietic organ in groups 1-5. The incidences of adenocarcinoma in small and large intestines of male rats of group 4 (50 mg/kg MNU and X-irradiation) (small intestine: 48%, large intestine: 32%) were significantly higher than those of group 2 (50 mg/kg MNU) (small intestine: 17%, p<0.05; large intestine: 8%, p<0.05), and also the frequency of adenocarcinoma in the large intestine of males of group 3 (25 mg/kg MNU and X-irradiation) (22%) was significantly greater than that of group 1 (25 mg/kg MNU) (0%, p<0.05). These results indicated that X-irradiation enhanced the development of intestinal neoplasms induced by MNU in male ACI/N rats. (author)

Effects of X-irradiation on N-methyl-N-nitrosourea-induced multi-organ carcinogenesis in rats

Energy Technology Data Exchange (ETDEWEB)

Morishita, Yukiko; Tanaka, Takuji; Mori, Hideki (Gifu Univ. (Japan). Faculty of Medicine); Sasaki, Shunsaku

1993-01-01

The effects of X-irradiation on N-methyl-N-nitrosourea (MNU)-induced multi-organ carcinogenesis were examined in both sexes of ACI/N rats. At 6 weeks of age, rats in groups 1 (25 males, 25 females) and 3 (24 males, 23 females) received a single intraperitoneal injection of MNU (25 mg/kg body weight), while those in groups 2 (25 males, 26 females) and 4 (25 males, 25 females) were administered the carcinogen at a dose of 50 mg/kg body weight. At 10 weeks of age, group 3 and group 4 were X-irradiated at dose of 3 Gy. Group 5 (24 males, 24 females) received X-irradiation alone. Group 6 (21 males, 21 females) served as an untreated control. As a result, neoplasms developed mainly in the digestive tract, kidney, uterus, and hematopoietic organ in groups 1-5. The incidences of adenocarcinoma in small and large intestines of male rats of group 4 (50 mg/kg MNU and X-irradiation) (small intestine: 48%, large intestine: 32%) were significantly higher than those of group 2 (50 mg/kg MNU) (small intestine: 17%, p<0.05; large intestine: 8%, p<0.05), and also the frequency of adenocarcinoma in the large intestine of males of group 3 (25 mg/kg MNU and X-irradiation) (22%) was significantly greater than that of group 1 (25 mg/kg MNU) (0%, p<0.05). These results indicated that X-irradiation enhanced the development of intestinal neoplasms induced by MNU in male ACI/N rats. (author).

Microalgae wet extraction using N-ethyl butylamine for fatty acid production

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Ying Du

2016-04-01

Full Text Available Microalgae are considered a promising feedstock for the production of food ingredients, cosmetics, pharmaceutical products and biofuels. The energy intensity of drying and cell breaking of algae and solvent recovery afterwards hindered the route of algae biorefinery. In this work the influences of freeze drying and cell breaking to the extraction efficiency of crude lipid yield and fatty acid yield were investigated. Results showed that drying and cell breaking are not necessary for N-ethyl butylamine extraction, because good yields were obtained without. Crude lipid yield and fatty acid yield using N-ethyl butylamine were comparable with Bligh & Dyer extraction, making N-ethyl butylamine a candidate for further development of an energy efficient lipid extraction technology for non-broken microalgae. Keywords: Microalgae, Lipids, Extraction, Switchable solvent, Secondary amine

Synthesis of N-methyl-N-nitrosourea linked to a methidium chloride analogue and its reactions with 32P-end-labeled DNA

International Nuclear Information System (INIS)

Konakahara, T.; Wurdeman, R.L.; Gold, B.

1988-01-01

The synthesis and characterization of an N-methyl-N-nitrosourea (MNU) analogue that is covalently linked to methidium nucleus (9) is described. At 37/degrees/C in pH 8.0 buffer 9 hydrolyzes via pseudo-first-order kinetics, with a calculated t/sub 1/2/ = 77 min. By use of polyacrylamide sequencing gels the formation of piperidine-labile N 7 -methylguanine adducts from the reaction of 9 and MNU with 5'- 32 P-end-labeled DNA restriction fragments is reported. DNA methylation by 9 in 10 mM Tris buffer is enhanced with increasing ionic strength (50-200 mM NaCl), which contrasts to the inhibition of MNU-induced cleavage with increasing salt. In addition, 9 methylates all G sites equally, while MNU shows a clear preference for d(G)/sub n/ (n ≥ 3) runs and an asymmetrical methylation pattern within these G-rich regions. The results are discussed in terms of the delivery of the MNU moiety to the DNA target by a non-sequence-specific intercalation process and the subsequent hydrolytic generation of a nondiffusible alkylating intermediate

Influence of N-methyl-N-nitrosourea, testosterone, and N-(4-hydroxyphenyl)-all-trans-retinamide on prostate cancer induction in Wistar-Unilever rats.

Science.gov (United States)

McCormick, D L; Rao, K V; Dooley, L; Steele, V E; Lubet, R A; Kelloff, G J; Bosland, M C

1998-08-01

The influence of chemical carcinogen, hormonal stimulation, and chronic dietary administration of the synthetic retinoid, N-(4-hydroxyphenyl)-all-trans-retinamide (4-HPR), on the induction of prostate cancer in male Wistar-Unilever rats was determined. Three different tumor induction regimens were used: (a) a single i.v. dose of 50 mg of N-methyl-N-nitrosourea (MNU) per kg body weight, followed by chronic androgen stimulation via s.c. implantation of two silastic capsules containing 40 mg testosterone each; (b) a single i.v. dose of 50 mg of MNU per kg body weight (no testosterone treatment); and (c) chronic androgen stimulation with implanted testosterone capsules (no MNU treatment). In a fourth series of animals, the incidence of spontaneous prostate tumors was determined in groups of rats receiving neither carcinogen nor hormone stimulation. Within each series, parallel groups of animals were fed a control (vehicle-supplemented) diet or control diet supplemented with 4-HPR beginning 1 day after carcinogen administration; retinoid administration was continuous until termination of the study at 450 days. The incidence of accessory sex gland cancer in rats treated sequentially with MNU + testosterone was >60%, in comparison with cancer incidences of Unilever rats.

Effects of Dietary Xanthophylls, Canthaxanthin and Astaxanthin on N-Methyl-N-nitrosourea-induced Rat Mammary Carcinogenesis.

Science.gov (United States)

Yuri, Takashi; Yoshizawa, Katsuhiko; Emoto, Yuko; Kinoshita, Yuichi; Yuki, Michiko; Tsubura, Airo

Natural xanthophylls, canthaxanthin and astaxanthin are known to exhibit anticancer activity. However, the dietary effects of canthaxanthin and astaxanthin on N-methyl-N-nitrosourea (MNU)-induced mammary cancer remain controversial, and their mechanisms of action have not been clearly identified. Three-week-old female Sprague-Dawley rats were fed a xanthophyll-free (basal diet) diet or experimental diets containing canthaxanthin or astaxanthin (0.04% and 0.4%) for 5 weeks (until 8 weeks of age), after which all rats were provided the basal diet (n=15 each). Rats were administered MNU at 6 weeks of age, and the incidence of mammary tumors at 20 weeks of age was compared. The expression of adiponectin in mammary adipose tissues taken at 7 weeks of age was also compared. Compared to the basal diet group, the 0.4% (but not the 0.04%) astaxanthin diet significantly reduced the incidence of palpable mammary carcinoma (92% vs. 42%; p<0.05), while the low and high canthaxanthin diets produced no significant inhibition. Adiponectin immunoblotting showed significantly higher expression in the 0.4% astaxanthin diet group, while the other groups were similar to the basal diet group. High concentrations of astaxanthin suppress MNU-induced mammary carcinoma. Changes in adiponectin may be involved in the mechanism of action. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

U.v.-induced and N-methyl-N'-nitrosoguanidine-induced mutagenesis in Bacillus thuringiensis

International Nuclear Information System (INIS)

Auffray, Y.; Boutibonnes, P.

1987-01-01

The lethal and mutagenic effects of u.v. light and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on Bacillus thuringiensis were investigated. Lethality studies demonstrated that B. thuringiensis was relatively sensitive to these agents. This bacterium was mutated at the rifampicin resistance marker by u.v. light and to a lesser extent by the direct acting alkylating agent MNNG. One mutant selected for its greater sensitivity to u.v. light expressed a higher frequency of mutagenesis after u.v. light treatment and appeared to be defective in an excision repair pathway. However, this mutant was only slightly mutable by MNNG in comparison with the wild-type strain. This unusual phenotype does not yet have a parallel among the radiation sensitive mutants described in other bacterial species. (author)

Antigenotoxic effects of Citrus aurentium L. fruit peel oil on mutagenicity of two alkylating agents and two metals in the Drosophila wing spot test.

Science.gov (United States)

Demir, Eşref; Kocaoğlu, Serap; Cetin, Huseyin; Kaya, Bülent

2009-07-01

Antigenotoxic effects of Citrus aurentium L. (Rutaceae) fruit peel oil (CPO) in combination with mutagenic metals and alkylating agents were studied using the wing spot test of D. melanogaster. The four reference mutagens, potassium dichromate (K2Cr2O7), cobalt chloride (CoCl2), ethylmethanesulfonate (EMS), and N-ethyl-N-nitrosourea (ENU) were clearly genotoxic. CPO alone at doses from 0.1 to 0.5% in Tween 80 was not mutagenic and did not enhance the mutagenic effect of the reference mutagens. However, antigenotoxic effects of CPO were clearly demonstrated in chronic cotreatments with mutagens and oil, by a significant decrease in wing spots induced by all four mutagens. The D. melanogaster wing spot test was found to be a suitable assay for detecting antigenotoxic effects in vivo. Copyright 2009 Wiley-Liss, Inc.

Overexpression of metallothioneins, stem cell niches and field cancerization in experimental gliomagenesis Superexpresión de metalotioneínas, nichos de células madre y campos de cancerización en gliomagénesis experimental A superexpressão de metalotioneínas em células-tronco de áreas cancerígenas na gênese de glioma experimental

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Julio César Fernandes da Silva

2009-12-01

Full Text Available INTRODUCTION: stem cells may originate and perpetuate the tumor growth, but they are poorly known in gliomagenesis. Metallothioneins (MTs are proteins involved in oncogenesis and immunopositivity, for MT may be used as a stem cell mutation marker. OBJECTIVE: to study the MT expression in the ENU experimental model and to establish an experimental model to track glioma stem cells in early oncogenesis. METHODS: Thirty-six male Wistar rats were divided into two groups; the experimental group was treated within 24 hours after birth (neonate rats with a single dose of subcutaneously injected N-ethyl N-nitrosourea ENU (40 mg/kg body weight. The control animals were injected with the same volume of saline. These experimental animals were subdivided into three groups according to the euthanize time, as follows: the Group 1 (G1 was euthanized at the age of 30 days; the Group 2 (G2, at the age of 180 days and the Group 3 (G3 was euthanized soon after the appearing of signs of the existence of nervous system tumors, at an average age of 321 days. Immunohistochemical detection of MT protein in cold acetone-fixed paraffin embedded spine cord sections was performed by the streptavidin-avidin-biotin-immuno peroxidase complex method. RESULTS: by using the experimental model of gliomagenesis induced by the N-ethyl N-nitrosourea, it was possible to detect putative tumor stem cells in early oncogenesis, to analyze a field cancerization process and to observe a close morphological relationship between MT positive cells and blood vessels. CONCLUSIONS: this reproducible experimental model allows further studies on the origins, development and regulating factors involved in gliomagenesis.INTRODUCCIÓN: células madre pueden originar y perpetuar el crecimiento tumoral, sin embargo son poco conocidas en la gliomagénesis. Las metalotioneínas (MTs son proteínas involucradas en la oncogénesis, y la inmunopositividad de las MTs puede ser utilizada como marcador de

Conserved role of unc-79 in ethanol responses in lightweight mutant mice.

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David J Speca

2010-08-01

Full Text Available The mechanisms by which ethanol and inhaled anesthetics influence the nervous system are poorly understood. Here we describe the positional cloning and characterization of a new mouse mutation isolated in an N-ethyl-N-nitrosourea (ENU forward mutagenesis screen for animals with enhanced locomotor activity. This allele, Lightweight (Lwt, disrupts the homolog of the Caenorhabditis elegans (C. elegans unc-79 gene. While Lwt/Lwt homozygotes are perinatal lethal, Lightweight heterozygotes are dramatically hypersensitive to acute ethanol exposure. Experiments in C. elegans demonstrate a conserved hypersensitivity to ethanol in unc-79 mutants and extend this observation to the related unc-80 mutant and nca-1;nca-2 double mutants. Lightweight heterozygotes also exhibit an altered response to the anesthetic isoflurane, reminiscent of unc-79 invertebrate mutant phenotypes. Consistent with our initial mapping results, Lightweight heterozygotes are mildly hyperactive when exposed to a novel environment and are smaller than wild-type animals. In addition, Lightweight heterozygotes exhibit increased food consumption yet have a leaner body composition. Interestingly, Lightweight heterozygotes voluntarily consume more ethanol than wild-type littermates. The acute hypersensitivity to and increased voluntary consumption of ethanol observed in Lightweight heterozygous mice in combination with the observed hypersensitivity to ethanol in C. elegans unc-79, unc-80, and nca-1;nca-2 double mutants suggests a novel conserved pathway that might influence alcohol-related behaviors in humans.

A convenient method to synthesize N-[3H]methyl-N-nitrosocarbamate transfer reagents

International Nuclear Information System (INIS)

Mehta, P.; Gold, B.; Konakahara, T.

1992-01-01

Activated N-alkyl-N-nitrosocarbamates are useful acyl transfer reagents that are employed in the synthesis of N-alkyl-N-nitrosoureas and related N-nitroso compounds. The nitrosourea products are of chemical and biological interest because they provide access to the in situ generation of highly reactive carbonium type intermediates, which, depending on their structure, can be powerful carcinogens or antineoplastic agents. The availability of radiolabeled nitrosoureas greatly facilitates studies on their chemical and biological activities. Generally, the synthesis of activated nitrosocarbamates requires condensation of radiolabeled alkylisocyanates with the appropriate alcohol. Because radiolabeled alkylisocyanates are not commercially available and/or troublesome to synthesize, we have developed an easy and economical method for preparing N-[ 3 H]methyl-N-nitrosocarbamates suitable for use as transfer reagents utilizing 1,2,2,2-tetrachloroethyl chloroformate and [ 3 H]methylamine hydrochloride as starting materials. (author)

Expression in mammalian cells of the Escherichia coli O6 alkylguanine-DNA-alkyltransferase gene ogt reduces the toxicity of alkylnitrosoureas.

Science.gov (United States)

Harris, L. C.; Margison, G. P.

1993-01-01

V79 Chinese hamster cells expressing either the O6-alkylguanine-DNA-alkyltransferase (ATase) encoded by the E. coli ogt gene or a truncated version of the E. coli ada gene have been exposed to various alkylnitrosoureas to investigate the contribution of ATase repairable lesions to the toxicity of these compounds. Both ATases are able to repair O6-alkylguanine (O6-AlkG) and O4-alkylthymine (O4-AlkT) but the ogt ATase is more efficient in the repair of O4-methylthymine (O4-MeT) and higher alkyl derivatives of O6-AlkG than is the ada ATase. Expression of the ogt ATase provided greater protection against the toxic effects of the alkylating agents then the ada ATase particularly with N-ethyl-N-nitrosourea (ENU) and N-butyl-N-nitrosourea (BNU) to which the ada ATase expressing cells were as sensitive as parent vector transfected cells. Although ogt was expressed at slightly higher levels than the truncated ada in the transfected cells, this could not account for the differential protection observed. For-N-methyl-N-nitrosourea (MNU) the increased protection in ogt-transfected cells is consistent with O4-MeT acting as a toxic lesion. For the longer chain alkylating agents and chloroethylating agents, the protection afforded by the ogt protein may be a consequence of the more efficient repair of O6-AlkG, O4-AlkT or both of these lesions in comparison with the ada-encoded ATase. Images Figure 2 Figure 3 PMID:8512805

Cadmium inhibits repair of UV-, methyl methanesulfonate- and N-methyl-N-nitrosourea-induced DNA damage in Chinese hamster ovary cells

International Nuclear Information System (INIS)

Fatur, Tanja; Lah, Tamara T.; Filipic, Metka

2003-01-01

The co-genotoxic effects of cadmium are well recognized and it is assumed that most of these effects are due to the inhibition of DNA repair. We used the comet assay to analyze the effect of low, non-toxic concentrations of CdCl 2 on DNA damage and repair-induced in Chinese hamster ovary (CHO) cells by UV-radiation, by methyl methanesulfonate (MMS) and by N-methyl-N-nitrosourea (MNU). The UV-induced DNA lesions revealed by the comet assay are single-strand breaks which are the intermediates formed during nucleotide excision repair (NER). In cells exposed to UV-irradiation alone the formation of DNA strand breaks was rapid, followed by a fast rejoining phase during the first 60 min after irradiation. In UV-irradiated cells pre-exposed to CdCl 2 , the formation of DNA strand breaks was significantly slower, indicating that cadmium inhibited DNA damage recognition and/or excision. Methyl methanesulfonate and N-methyl-N-nitrosourea directly alkylate nitrogen and oxygen atoms of DNA bases. The lesions revealed by the comet assay are mainly breaks at apurinic/apyrimidinic (AP) sites and breaks formed as intermediates during base excision repair (BER). In MMS treated cells the initial level of DNA strand breaks did not change during the first hour of recovery; thereafter repair was detected. In cells pre-exposed to CdCl 2 the MMS-induced DNA strand breaks accumulated during the first 2 h of recovery, indicating that AP sites and/or DNA strand breaks were formed but that further steps of BER were blocked. In MNU treated cells the maximal level of DNA strand breaks was detected immediately after the treatment and the breaks were repaired rapidly. In CdCl 2 pre-treated cells the formation of MNU-induced DNA single-strand breaks was not affected, while the repair was slower, indicating inhibition of polymerization and/or the ligation step of BER. Cadmium thus affects the repair of UV-, MMS- and MNU-induced DNA damage, providing further evidence, that inhibition of DNA repair

Distribution of N-methyl-N-nitrosourea in the Amazon molly, Poecilla formosa (Girard), after a single intraperitoneal injection

Energy Technology Data Exchange (ETDEWEB)

Woodhead, A.D.; Cao, E.H.; Melgar, T.

1985-01-01

The distribution and accumulation of labelled N-methyl-N nitrosourea (MNU) has been described in the Amazon molly following intraperitoneal injection. Two hours after injection the label was present throughout the body, with enhanced deposition in the macrophages of the atrium of the heart, the kidney and the spleen; about half of the liver cells were labelled. The compound was taken up by the cells of the renal excretory tubules, and certain cells in the optic tectum and corpus cerebelli of the brain. By 6 h, the distribution picture had changed radically. There was little label remaining, except in a few macrophages in the heart and kidneys, and in the nuclei of the renal tubule cells. There was a slight decrease in the numbers of cells in the brain that were labelled, but the amount of material that the individual cells had accumulated had increased. By 48 h there was further loss and only brain cells were labelled. Our findings indicate preferential accumulation of MNU in undifferentiated, pluripotential cells of the optic tectum and corpus cerebelli. 28 references, 3 figures, 1 table.

A convenient method to synthesize N-[[sup 3]H]methyl-N-nitrosocarbamate transfer reagents

Energy Technology Data Exchange (ETDEWEB)

Mehta, P.; Gold, B. (Nebraska Univ., Omaha, NE (United States). Eppley Inst. for Research in Cancer); Konakahara, T. (Science Univiversity of Tokyo, Noda, Chiba (Japan). Faculty of Science and Technology)

1992-11-01

Activated N-alkyl-N-nitrosocarbamates are useful acyl transfer reagents that are employed in the synthesis of N-alkyl-N-nitrosoureas and related N-nitroso compounds. The nitrosourea products are of chemical and biological interest because they provide access to the in situ generation of highly reactive carbonium type intermediates, which, depending on their structure, can be powerful carcinogens or antineoplastic agents. The availability of radiolabeled nitrosoureas greatly facilitates studies on their chemical and biological activities. Generally, the synthesis of activated nitrosocarbamates requires condensation of radiolabeled alkylisocyanates with the appropriate alcohol. Because radiolabeled alkylisocyanates are not commercially available and/or troublesome to synthesize, we have developed an easy and economical method for preparing N-[[sup 3]H]methyl-N-nitrosocarbamates suitable for use as transfer reagents utilizing 1,2,2,2-tetrachloroethyl chloroformate and [[sup 3]H]methylamine hydrochloride as starting materials. (author).

Chemical structure of carbamoylating groups and their relationship to bone marrow toxicity and antiglioma activity of bifunctionally alkylating and carbamoylating nitrosoureas.

Science.gov (United States)

Ali-Osman, F; Giblin, J; Berger, M; Murphy, M J; Rosenblum, M L

1985-09-01

Although the antitumor effects of chloroethylnitrosoureas have been shown to be due primarily to DNA-DNA cross-linking by the alkylating moieties of these agents, the basis of the often accompanying bone marrow toxicity has been more controversial. We report on the relative bone marrow toxicity of four model nitrosoureas with different alkylating and carbamoylating activities: 1,3-bis(2-chloroethyl)-1-nitrosourea; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea; chlorozotozin, (2-[3-(2-chloroethyl)-3 -nitrosoureido]-2-deoxy-D-glucopyranose); and -3-(beta-D-glucopyranosyl)-1-nitrosourea. Inhibitions of DNA, RNA, and protein synthesis in murine bone marrow cells and of colony growth of myeloid precursor cells (granulocyte-macrophage colony-forming units) were used as in vitro end points of myelotoxicity. Further, we determined the antiglioma activity of the four nitrosoureas on two human gliomas in a clonogenic tumor cell assay and studied the effect of the non-nitrosourea carbamoylators potassium cyanate, chloroethyl isocyanate, cyclohexyl isocyanate, ethyl isocyanate, and ethyl isothiocyanate on granulocyte-macrophage colony-forming units. The results show that, at equivalent drug exposures, clonogenic glioma cell kill was significant and comparative for 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea, and chlorozotocin; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea showed little activity. In contrast, granulocyte-macrophage colony-forming unit toxicity was low with chlorozotocin and 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea and very high with 1,3-bis(2-chloroethyl)-1-nitrosourea and 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea. Of the isocyanates, bone marrow toxicity was highest with chloroethyl isocyanate and cyclohexyl isocyanate, intermediate with ethyl isocyanate, and lowest with KOCN and ethyl isothiocyanate. Our results indicate that (a) bifunctional alkylation is essential for

Modification of N-Methyl-N-Nitrosourea initiated bladder carcinogenesis in Wistar rats by terephthalic acid

International Nuclear Information System (INIS)

Cui Lunbiao; Shi Yuan; Dai Guidong; Pan Hongxin; Chen Jianfeng; Song Ling; Wang Shouling; Chang, Hebron C.; Sheng Hongbing; Wang Xinru

2006-01-01

The effect of terephthalic acid (TPA) on urinary bladder carcinogenesis was examined. Male Wistar rats were initiated by injection of N-Methyl-N-Nitrosourea (MNU) (20 mg/kg b.w. ip) twice a week for 4 weeks, then given basal diet containing 5% TPA, 5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) or 1% TPA for the next 22 weeks, and then euthanized. 5% TPA treatment induced a high incidence of urinary bladder calculi and a large amount of precipitate. Though 5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) and 1% TPA treatment did not induce urinary bladder calculi formation, they resulted in a moderate increase in urinary precipitate. Histological examination of urinary bladder revealed that MNU-5% TPA treatment resulted in a higher incidence of simple hyperplasia, papillary or nodular hyperplasia (PN hyperplasia), papilloma and cancer than MNU control. MNU-5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) and 1% TPA treatment increased slightly the incidence of simple hyperplasia and PN hyperplasia (not statistically significant). The major elements of the precipitate are phosphorus, potassium, sulfur, chloride, calcium and TPA. The present study indicated that the calculi induced by TPA had a strong promoting activity on urinary bladder carcinogenesis and the precipitate containing calcium terephthalate (CaTPA) may also have weak promoting activity on urinary bladder carcinogenesis

Interstrand cross-linking of DNA by 1,3-bis(2-chloroethyl)-1-nitrosourea and other 1-(2-haloethyl)-1-nitrosoureas.

Science.gov (United States)

Kohn, K W

1977-05-01

Bifunctional alkylating agents are known to cross-link DNA by simultaneously alkylating two guanine residues located on opposite strands. Despite this apparent requirement for bifunctionality, 1-(2-chloroethyl)-1-nitrosoureas bearing a single alkylating function were found to cross-link DNA in vitro. Cross-linking was demonstrated by showing inhibition of alkali-induced strand separation. Extensive cross-linking was observed in DNA treated with 1-(2-chloroethyl)-1-nitrosourea, 1,3-bis-(2-chloroethyl)-1-nitrosourea, and 1-(2-chloroethyl(-3-cyclohexyl-1-nitrosourea. The reaction occurs in two steps, an intital binding followed by a second step which can proceed after removal of unbound drug. It is suggested that the first step is chloroethylation of a nucleophilic site on one strand and that the second step involves displacement of Cl- by a nucleophilic site on the opposite strand, resulting in an ethyl bridge between the strands. Consistent with this possibility, 1-(2-fluoroethyl)-3-cyclohexyl-1-nitrosourea produced much less cross-linking, as expected from the known low activity of F-, compared with Cl-, as leaving group. 1-Methyl-1-nitrosourea, which is known to depurinate DNA, produced no detectable cross-linking.

Synthesis and Fungicidal activity of some sulphide derivatives of O-Ethyl-N-substituted phenylcarbamates

International Nuclear Information System (INIS)

Imeokparia, F.A.

2006-01-01

Monosulphides of O-ethyl-N-substituted phenylcarbamates were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur dichloride, while the corresponding disulphides were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur monochloride. The synthesized compounds were characterized by elemental analysis, thin layer chromatography (TLC), Fourier-transform infrared, and /sup 1/H and /sup 13/C nuclear magnetic resonance spectroscopic techniques. In vitro fungicidal assay of these sulphides against Fusarium oxysporum, Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer showed that they had Greater fungicidal activity than their parent carbamates. The synthesized sulphides were more active towards A. Niger and A. flavus. Unlike the parent carbamates, the type of substituents attached to the aromatic nucleus of these sulphides had little or no effect on their fungicidal activity as there was insignificant variation in the fungicidal activity of the monosulphide and the disulphide derivatives of O-ethyl-N-substituted phenylcarbamates. (author)

Nature of mutants induced by ionizing radiation in cultured hamster cells. II. Antigenic response and reverse mutation of HPRT-deficient mutants induced by. gamma. -rays or ethyl methanesulphonate

Energy Technology Data Exchange (ETDEWEB)

Brown, R; Stretch, A; Thacker, J

1986-04-01

A large series of independent mutants deficient in HPRT enzyme activity, isolated from V79-4 hamster cells, were assessed for properties which reflect the nature of the genetic changes induced. A total of 88 mutants were screened, 43 isolated from ..gamma..-ray-treated cultures and 45 induced by ethyl methanesulphonate (EMS). Firstly, each mutant was assayed for the presence of protein with the antigenic response of HPRT. In a competitive inhibition assay, 31% of EMS-induced mutants were CRM-positive compared to 7% of the ..gamma..-ray series. Secondly, each mutant was tested for ability to revert to HPRT proficiency. All except 2 of the EMS-induced mutants reverted with ethyl nitrosourea ENU, and many reverted spontaneously, under the given conditions. However reversion was not detected in about 80% of ..gamma..-ray-induced mutants, suggesting that the types of forward mutation caused by ionizing radiation differ qualitatively from those caused by EMS. (Auth.). 30 refs.; 6 figs.; 2 tabs.

Creation of miniature pig model of human Waardenburg syndrome type 2A by ENU mutagenesis.

Science.gov (United States)

Hai, Tang; Guo, Weiwei; Yao, Jing; Cao, Chunwei; Luo, Ailing; Qi, Meng; Wang, Xianlong; Wang, Xiao; Huang, Jiaojiao; Zhang, Ying; Zhang, Hongyong; Wang, Dayu; Shang, Haitao; Hong, Qianlong; Zhang, Rui; Jia, Qitao; Zheng, Qiantao; Qin, Guosong; Li, Yongshun; Zhang, Tao; Jin, Weiwu; Chen, Zheng-Yi; Wang, Hongmei; Zhou, Qi; Meng, Anming; Wei, Hong; Yang, Shiming; Zhao, Jianguo

2017-11-01

Human Waardenburg syndrome 2A (WS2A) is a dominant hearing loss (HL) syndrome caused by mutations in the microphthalmia-associated transcription factor (MITF) gene. In mouse models with MITF mutations, WS2A is transmitted in a recessive pattern, which limits the study of hearing loss (HL) pathology. In the current study, we performed ENU (ethylnitrosourea) mutagenesis that resulted in substituting a conserved lysine with a serine (p. L247S) in the DNA-binding domain of the MITF gene to generate a novel miniature pig model of WS2A. The heterozygous mutant pig (MITF +/L247S ) exhibits a dominant form of profound HL and hypopigmentation in skin, hair, and iris, accompanied by degeneration of stria vascularis (SV), fused hair cells, and the absence of endocochlear potential, which indicate the pathology of human WS2A. Besides hypopigmentation and bilateral HL, the homozygous mutant pig (MITF L247S/L247S ) and CRISPR/Cas9-mediated MITF bi-allelic knockout pigs both exhibited anophthalmia. Three WS2 patients carrying MITF mutations adjacent to the corresponding region were also identified. The pig models resemble the clinical symptom and molecular pathology of human WS2A patients perfectly, which will provide new clues for better understanding the etiology and development of novel treatment strategies for human HL.

TRANSPORT PROPERTIES FOR 1-ETHYL-3-METHYLIMIDAZOLIUM n-ALKYL SULFATES: POSSIBLE EVIDENCE OF GROTTHUSS MECHANISM

International Nuclear Information System (INIS)

García-Garabal, S.; Vila, J.; Rilo, E.; Domínguez-Pérez, M.; Segade, L.; Tojo, E.; Verdía, P.; Varela, L.M.; Cabeza, O.

2017-01-01

The objective of this work was to study the effect of the temperature and the lengthening of the linear alkyl chain of the anion in the transport physical properties of the pure ionic liquids 1-ethyl-3-methyl imidazolium n-alkyl sulphate (being n = 0, 1, 2, 4, 6 and 8). Density, viscosity and electrical conductivities were measured at atmospheric pressure in a wide temperature range. In the bibliography, data existed for these magnitudes for all ionic liquids studied but none of these had information about the electrical conductivity of 1-ethyl-3-methyl imidazolium n-alkyl sulfate whith n = 0, 4, 6 and 8. The experimental results show clearly 1-ethyl-3-methyl imidazolium hydrogen sulphate cannot be considered part of the 1-ethyl-3-methyl imidazolium n-alkyl sulphate family because of its hydrogen bonding ability. Results of density and viscosity behave as expected. However, in the case of the electrical conductivity due to the lack of alkyl chain in the hydrogen sulfate we expected to get extreme values but in practise, we obtained intermediate values between 1-ethyl-3-methyl imidazolium butyl sulphate and 1-ethyl-3-methyl imidazolium hexyl sulphate. This suggests that a Grotthus mechanism exists as result of a protonic current in addition to ionic conductivity, being Waldeńs plot consistent with this idea.

umuC-mediated misrepair mutagenesis in Escherichia coli: Extent and specificity of SOS mutagenesis

International Nuclear Information System (INIS)

Shinoura, Y.; Ise, T.; Kato, T.; Glickman, B.W.

1983-01-01

The role of the error-prone misrepair pathway in mutagenesis was examined for a series of mutagens in umuC + and umuC36 strains of Escherichia coli. Mutagenesis by ENU, MNU, MNNG and EMS was independent of the umuC + gene function, while mutagenesis by MMS, 4NQO, γ-rays and UV was largely umuC + -dependent. Residual mutagenesis following UV-treatment of a umuC - strain showed the same mutational specificity seen in the umuC + strain. In contrast, the umuC mutation altered specificity substantially in an excision-repair-defective strain that showed a UV-spectrum strikingly different from that seen in an excision-repair-proficient strain. Only one of nine trpE frameshift mutations examined was reverted by UV-light and its reversion was umuC-dependent. In comparison, the dependence of frameshift mutagenesis following ICR191 treatment was site-specific, suggesting at least two mechanisms of frameshift mutagenesis, one dependent upon misrepair, the other not. (orig./AJ)

Biomonitoring of N-ethyl-2-pyrrolidone in automobile varnishers.

Science.gov (United States)

Koslitz, Stephan; Meier, Swetlana; Schindler, Birgit Karin; Weiss, Tobias; Koch, Holger Martin; Brüning, Thomas; Käfferlein, Heiko Udo

2014-12-01

N-alkyl-2-pyrrolidones are important organic solvents for varnishes in industry. This study investigates exposure to N-ethyl-2-pyrrolidone (NEP) in varnishing of hard plastic components in an automobile plant. Two specific biomarkers of exposure, 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI), were analyzed in urine samples of 14 workers. For this purpose, pre-shift, post-shift and next day pre-shift urine samples were collected midweek. Twelve workers performed regular work tasks (loading, wiping and packing), whereas two workers performed special work tasks including cleaning the sprayer system with organic solvents containing N-alkyl-2-pyrrolidones. Spot urine samples of nine non-exposed persons of the same plant served as controls. Median post-shift urinary levels of workers with regular work tasks (5-HNEP: 0.15 mg/L; 2-HESI: 0.19 mg/L) were ∼5-fold higher compared to the controls (0.03 mg/L each). Continuously increasing metabolite levels, from pre-shift via post-shift to pre-shift samples of the following day, were observed in particular for the two workers with the special working tasks. Maximum levels were 31.01 mg/L (5-HNEP) and 8.45 mg/L (2-HESI). No clear trend was evident for workers with regular working tasks. In summary, we were able to show that workers can be exposed to NEP during varnishing tasks in the automobile industry. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cancer of rat ovaries: Sertoli cell or granulosa-theca cell tumours

International Nuclear Information System (INIS)

Knowles, J.F.

1983-01-01

The effects of X-radiation (0-1.25 Gy) given 24 hours after neonatal injections of the carcinogen ethyl nitrosourea (ENU) (0-10 mg/kg) in female rats were studied. Twelve out of 118 rats bore single ovarian tumours. A substantial excess of ovarian tumours occurred in the rats given 4 mg/kg ENU and 1.25 GY X-rays but not in others given ENU alone, radiation alone or 10 mg/kg ENU and 1.25 Gy. The tumours were all found in old rats (657-1085 days). In all of the tumours the presence of tubular formations suggested a diagnosis of ovarian Sertoli cell tumour. In two tumours, only a few tubular structures were seen and fibrous stromal tissue predominated, suggesting a diagnosis of granulosa-theca cell tumour. All other tumours were a mixture of both elements. (U.K.)

Comparing BMD-derived genotoxic potency estimations across variants of the transgenic rodent gene mutation assay.

Science.gov (United States)

Wills, John W; Johnson, George E; Battaion, Hannah L; Slob, Wout; White, Paul A

2017-12-01

There is growing interest in quantitative analysis of in vivo genetic toxicity dose-response data, and use of point-of-departure (PoD) metrics such as the benchmark dose (BMD) for human health risk assessment (HHRA). Currently, multiple transgenic rodent (TGR) assay variants, employing different rodent strains and reporter transgenes, are used for the assessment of chemically-induced genotoxic effects in vivo. However, regulatory issues arise when different PoD values (e.g., lower BMD confidence intervals or BMDLs) are obtained for the same compound across different TGR assay variants. This study therefore employed the BMD approach to examine the ability of different TGR variants to yield comparable genotoxic potency estimates. Review of over 2000 dose-response datasets identified suitably-matched dose-response data for three compounds (ethyl methanesulfonate or EMS, N-ethyl-N-nitrosourea or ENU, and dimethylnitrosamine or DMN) across four commonly-used murine TGR variants (Muta™Mouse lacZ, Muta™Mouse cII, gpt delta and BigBlue® lacI). Dose-response analyses provided no conclusive evidence that TGR variant choice significantly influences the derived genotoxic potency estimate. This conclusion was reliant upon taking into account the importance of comparing BMD confidence intervals as opposed to directly comparing PoD values (e.g., comparing BMDLs). Comparisons with earlier works suggested that with respect to potency determination, tissue choice is potentially more important than choice of TGR assay variant. Scoring multiple tissues selected on the basis of supporting toxicokinetic information is therefore recommended. Finally, we used typical within-group variances to estimate preliminary endpoint-specific benchmark response (BMR) values across several TGR variants/tissues. We discuss why such values are required for routine use of genetic toxicity PoDs for HHRA. Environ. Mol. Mutagen. 58:632-643, 2017. © 2017 Her Majesty the Queen in Right of Canada

Cell Fate of Müller Cells During Photoreceptor Regeneration in an N-Methyl-N-nitrosourea-Induced Retinal Degeneration Model of Zebrafish.

Science.gov (United States)

Ogai, Kazuhiro; Hisano, Suguru; Sugitani, Kayo; Koriyama, Yoshiki; Kato, Satoru

2016-01-01

Zebrafish can regenerate several organs such as the tail fin, heart, central nervous system, and photoreceptors. Very recently, a study has demonstrated the photoreceptor regeneration in the alkylating agent N-methyl-N-nitrosourea (MNU)-induced retinal degeneration (RD) zebrafish model, in which whole photoreceptors are lost within a week after MNU treatment and then regenerated within a month. The research has also shown massive proliferation of Müller cells within a week. To address the question of whether proliferating Müller cells are the source of regenerating photoreceptors, which remains unknown in the MNU-induced zebrafish RD model, we employed a BrdU pulse-chase technique to label the proliferating cells within a week after MNU treatment. As a result of the BrdU pulse-chase technique, a number of BrdU(+) cells were observed in the outer nuclear layer as well as the inner nuclear layer. This implies that regenerating photoreceptors are derived from proliferating Müller cells in the zebrafish MNU-induced RD model.

Niacin deficiency delays DNA excision repair and increases spontaneous and nitrosourea-induced chromosomal instability in rat bone marrow.

Science.gov (United States)

Kostecki, Lisa M; Thomas, Megan; Linford, Geordie; Lizotte, Matthew; Toxopeus, Lori; Bartleman, Anne-Pascale; Kirkland, James B

2007-12-01

We have shown that niacin deficiency impairs poly(ADP-ribose) formation and enhances sister chromatid exchanges and micronuclei formation in rat bone marrow. We designed the current study to investigate the effects of niacin deficiency on the kinetics of DNA repair following ethylation, and the accumulation of double strand breaks, micronuclei (MN) and chromosomal aberrations (CA). Weanling male Long-Evans rats were fed niacin deficient (ND), or pair fed (PF) control diets for 3 weeks. We examined repair kinetics by comet assay in the 36h following a single dose of ethylnitrosourea (ENU) (30mg/kg bw). There was no effect of ND on mean tail moment (MTM) before ENU treatment, or on the development of strand breaks between 0 and 8h after ENU. Repair kinetics between 12 and 30h were significantly delayed by ND, with a doubling of area under the MTM curve during this period. O(6)-ethylation of guanine peaked by 1.5h, was largely repaired by 15h, and was also delayed in bone marrow cells from ND rats. ND significantly enhanced double strand break accumulation at 24h after ENU. ND alone increased chromosome and chromatid breaks (four- and two-fold). ND alone caused a large increase in MN, and this was amplified by ENU treatment. While repair kinetics suggest that ND may be acting by creating catalytically inactive PARP molecules with a dominant-negative effect on repair processes, the effect of ND alone on O(6)-ethylation, MN and CA, in the absence of altered comet results, suggests additional mechanisms are also leading to chromosomal instability. These data support the idea that the bone marrow cells of niacin deficient cancer patients may be more sensitive to the side effects of genotoxic chemotherapy, resulting in acute bone marrow suppression and chronic development of secondary leukemias.

Study of the rearrangement of N-alkylaniline to p-aminoalkylbencene. I. N-ethyl-l-{sup 1}4C-aniline; Estudio de la transposicion de N-alquilanilinas A p-Aminoalquilbenceno mediante {sup 1}4C

Energy Technology Data Exchange (ETDEWEB)

Molera, M J; Gamboa, J M; Val Cob, M del

1961-07-01

The rearrangement of N-ethylaniline to p-aminoethylbenzene has been studied over the temperature range 200-300 degree centigrade using different catalysts: Cl{sub 2}Co, Cl{sub 2}Zn, Cl{sub 2}Ni, Cl{sub 3}Al, Cl{sub 2}Cd and Br H.N-ethyl-1-{sup 1}4C-aniline has been synthesized from ethyl-1-{sup 1}4C-iodide and aniline and its rearrangement to p-aminoethyl-benzene proves that the ethyl group does not rearrange itself during the reaction. A scheme for the degradation of both the N-ethyl-1-{sup 1}4C aniline and the p-aminoethylbenzene produces is described. (Author) 14 refs.

Comprehensive behavioral analysis of ENU-induced Disc1-Q31L and -L100P mutant mice

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Shoji Hirotaka

2012-02-01

Full Text Available Abstract Background Disrupted-in-Schizophrenia 1 (DISC1 is considered to be a candidate susceptibility gene for psychiatric disorders, including schizophrenia, bipolar disorder, and major depression. A recent study reported that N-ethyl-N-nitrosourea (ENU-induced mutations in exon 2 of the mouse Disc1 gene, which resulted in the amino acid exchange of Q31L and L100P, caused an increase in depression-like behavior in 31 L mutant mice and schizophrenia-like behavior in 100P mutant mice; thus, these are potential animal models of psychiatric disorders. However, remaining heterozygous mutations that possibly occur in flanking genes other than Disc1 itself might induce behavioral abnormalities in the mutant mice. Here, to confirm the effects of Disc1-Q31L and Disc1-L100P mutations on behavioral phenotypes and to investigate the behaviors of the mutant mice in more detail, the mutant lines were backcrossed to C57BL/6JJcl through an additional two generations and the behaviors were analyzed using a comprehensive behavioral test battery. Results Contrary to expectations, 31 L mutant mice showed no significant behavioral differences when compared with wild-type control mice in any of the behavioral tests, including the Porsolt forced swim and tail suspension tests, commonly used tests for depression-like behavior. Also, 100P mutant mice exhibited no differences in almost all of the behavioral tests, including the prepulse inhibition test for measuring sensorimotor gating, which is known to be impaired in schizophrenia patients; however, 100P mutant mice showed higher locomotor activity compared with wild-type control mice in the light/dark transition test. Conclusions Although these results are partially consistent with the previous study in that there was hyperactivity in 100P mutant mice, the vast majority of the results are inconsistent with those of the previous study; this discrepancy may be explained by differences in the genetic background of the

Methylation of ribonucleic acid by the carcinogens dimethyl sulphate, N-methyl-N-nitrosourea and N-methyl-N′-nitro-N-nitrosoguanidine. Comparisons of chemical analyses at the nucleoside and base levels

Science.gov (United States)

Lawley, P. D.; Shah, S. A.

1972-01-01

1. The following methods for hydrolysis of methyl-14C-labelled RNA, and for chromatographic isolation and determination of the products, were investigated: enzymic digestion to nucleosides at pH6 or 8; alkaline hydrolysis and conversion into nucleosides; hydrolysis by acid to pyrimidine nucleotides and purine bases, or completely to bases; chromatography on Dowex 50 (NH4+ form) at pH6 or 8.9, or on Dowex 50 (H+ form), or on Sephadex G-10. 2. The suitability of the various methods for determination of methylation products was assessed. The principal product, 7-methylguanosine, was unstable under the conditions used for determinations of nucleosides. 3- and 7-Methyladenine and 3- and 7-methylguanine are best determined as bases; 1-methyladenine and 3-methylcytosine can be isolated as either nucleosides or bases; O6-methylguanine is unstable under the acid hydrolysis conditions used and can be determined as the nucleoside; 3-methyluracil was detected, but may be derived from methylation of the ionized form of uracil. 3. Differences between the patterns of methylation of RNA and homopolyribonucleotides by the N-methyl-N-nitroso compounds and dimethyl sulphate were found: the nitroso compounds were able to methylate O-6 of guanine, were relatively more reactive at N-7 of adenine and probably at N-3 of guanine, but less reactive at N-1 of adenine, N-3 of cytosine and probably at N-3 of uridine. They probably reacted more with the ribose–phosphate chain, but no products from this were identified. 4. The possible influences of these differences on biological action of the methylating agents is discussed. Nitroso compounds may differ principally in their ability to induce miscoding in the Watson–Crick sense by reaction at O-6 of guanine. Both types of agent may induce miscoding to a lesser extent through methylation at N-3 of guanine; both can methylate N atoms, presumably preventing Watson–Crick hydrogen-bonding. N-Methyl-N-nitrosourea can degrade RNA, possibly

The reduction of plutonium (IV) and neptunium (VI) ions by N,N-ethyl (hydroxyethyl) hydroxylamine in nitric acid

International Nuclear Information System (INIS)

Koltunov, V.S.; Baranov, S.M.; Mezhov, E.A.; Taylor, R.J.; May, I.

1999-01-01

The kinetics of the reduction of neptunium (VI) and plutonium (IV) ions in nitric acid solution by a new rapid salt free reductant, N,N-ethyl (hydroxyethyl) hydroxylamine, have been studied and rate equations determined. Under equivalent conditions, both Np(VI) and Pu(IV) are reduced faster than by the related reagent, N,N-diethyl hydroxylamine, and it is suggested that this is due to the introduction of the hydroxy group into the reductant molecule. Possible reaction mechanisms have been suggested to account for the observed reaction stoichiometry. (orig.)

DNA polymerase III of Escherichia coli is required for UV and ethyl methanesulfonate mutagenesis

Energy Technology Data Exchange (ETDEWEB)

Hagensee, M.E.; Timme, T.L.; Bryan, S.K.; Moses, R.E.

1987-06-01

Strains of Escherichia coli possessing the pcbA1 mutation, a functional DNA polymerase I, and a temperature-sensitive mutation in DNA polymerase III can survive at the restrictive temperature (43 degrees C) for DNA polymerase III. The mutation rate of the bacterial genome of such strains after exposure to either UV light or ethyl methanesulfonate was measured by its rifampicin resistance or amino acid requirements. In addition, Weigle mutagenesis of preirradiated lambda phage was also measured. In all cases, no increase in mutagenesis was noted at the restrictive temperature for DNA polymerase III. Introduction of a cloned DNA polymerase III gene returned the mutation rate of the bacterial genome as well as the Weigle mutagenesis to normal at 43 degrees C. Using a recA-lacZ fusion, the SOS response after UV irradiation was measured and found to be normal at the restrictive and permissive temperature for DNA polymerase III, as was induction of lambda prophage. Recombination was also normal at either temperature. Our studies demonstrate that a functional DNA polymerase III is strictly required for mutagenesis at a step other than SOS induction.

Preclinical studies of steroid-linked nitrosoureas in murine pancreatic adenocarcinoma PANO2.

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Papageorgiou, A; Lialiaris, Th; Stergiou, E; Stergiou, I; Tsigris, C; Kourti, A; Geromichalos, G; Stravoravdi, P; Trafalis, D; Athanassiou, A E; Pitsas, A; Camoutsis, Ch

2008-01-01

In earlier studies, this laboratory carried out research on the synthesis and anticancer evaluation of hybrid compounds, which combine two molecules in one such as homo-aza-steroidal esters (HASE) of carboxylic derivatives of N, N-bis (2-chloroethyl) aniline. In this combination, steroidal hormones are employed as carriers for transporting the alkylating agents to specific targeted tissues. Aiming to continue our research, we used alkylating agents, as nitrosoureas, instead of nitrogen mustards. In this work the N-[N- (2-chloroethyl)-N-nitroso-carbomoyl]-L-alanine (CNC-ala) has been used and was bound to 7 newly synthesized modified steroidal esters (carrier molecule) of nitrosourea and the hybrid molecules were tested for antitumor activity against PANO2 murine pancreatic adenocarcinoma. PANO2 adenocarcinoma was used in this study. C57Bl mice were used for chemotherapy evaluation. The activity was assessed from the inhibition of tumor growth and the oncostatic parameter T/C %. The antitumor activity displayed by 7 hybrid steroidal esters of nitrosourea was quite interesting. It was able to discern 4 of 7 compounds that exhibited considerable antitumor activity, increasing the lifespan of the tumor-bearing mice by inhibiting the tumor growth. The comparative study of 7 newly synthesized hybrid steroidal esters of nitrosourea shows that the antitumor effects of compound 7, which has an enlarged (7 carbon atoms) A-lactamic ring and nitrosourea esterified at the position 17, which seems to be the most appropriate for the connection of a DNA cross-linking amino acid derivative is superior.

Preventive effect of Oenothera rosea on N-methyl-N-nitrosourea-(NMU) induced gastric cancer in rats.

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Almora-Pinedo, Yuan; Arroyo-Acevedo, Jorge; Herrera-Calderon, Oscar; Chumpitaz-Cerrate, Víctor; Hañari-Quispe, Renán; Tinco-Jayo, Aldo; Franco-Quino, Cesar; Figueroa-Salvador, Linder

2017-01-01

Currently, gastric cancer (GC) is considered a public health problem worldwide. Using medicinal plants for the prevention of chronic diseases such as cancer constitutes new alternatives in traditional medicine. Oenothera rosea (OR) could be an option, but it needs to be evaluated. The main objective of this study was to evaluate the protective effect of OR extract on N-methyl-N-nitrosourea (NMU)-induced GC in rats. In total, 80 male Holtzman rats were randomized into five groups. Group A received the saline solution (5mL/kg), group B received NMU 500 μg/kg (cancer inductor) by oral administration for 16 weeks, and groups C, D, and E were treated with OR extract (100, 200, and 300 mg/kg, respectively) and NMU in order to evaluate the preventive effect on cancer induced by NMU for 16 weeks. Blood and histological samples of stomachs were collected to determine histopathological, biochemical, and hematological parameters between different experimental groups. Groups C, D, and E presented less histopathological changes such as anaplastic and hyperplastic cells, compared with group B. Hematological and biochemical parameters were recorded, and superoxide dismutase, malondialdehyde, and nitric oxide levels were statistically less than those of NMU group ( P <0.05, P <0.01, and P <0.01). Considering the histopathological signs and the antioxidant activity in vivo as well as hematological and biochemical parameters of ethanolic extract of OR, we concluded that its administration in rats has a protective effect on GC, which is induced experimentally. This species could be studied in clinical trials for patients with GC in the future.

Nitric oxide donors attenuate clongenic potential in rat C6 glioma cells treated with alkylating chemotherapeutic agents.

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Yang, Jir-Jei; Yin, Jiu-Haw; Yang, Ding-I

2007-05-11

1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) kills tumor cells via multiple actions including alkylation and carbamoylation. Previously, we have reported that formation of S-nitrosoglutathione (GSNO) in glioma cells overexpressing inducible nitric oxide synthase (iNOS) contributed to nitric oxide (NO)-dependent carbamoylating chemoresistance against BCNU. To further characterize the effects of NO on alkylating cytotoxicity, colony formation assay was applied to evaluate the effects of various NO donors on rat C6 glioma cells challenged with alkylating agents. We demonstrate that NO donors including GSNO, diethylamine NONOate (DEA/NO), and sodium nitroprusside (SNP) substantially reduced the extent of colony formation in glioma cells treated with alkylating agents, namely methyl methanesulfonate (MMS), N-methyl-N-nitrosourea (MNU), and N-ethyl-N-nitrosourea (ENU). Without alkylating agents these NO-releasing agents alone had no effects on clongenic potential of rat C6 glioma cells. Among these three NO donors used, the effectiveness in potentiating alkylating cytotoxicity is in the order of "GSNO>DEA/NO>SNP" when applied at the same dosages. GSNO also exerted similar synergistic actions reducing the extents of colony formation when co-administrated with 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-hydrazine (compound #1), another alkylating agent that mimics the chloroethylating action of BCNU. Together with our previous findings, we propose that NO donors may be used as adjunct chemotherapy with alkylating agents for such malignant brain tumors as glioblastoma multiforme (GBM). In contrast, production of NO as a result of iNOS induction, such as that occurring after surgical resection of brain tumors, may compromise the efficacy of carbamoylating chemotherapy.

ENU mutagenesis screening for dominant behavioral mutations based on normal control data obtained in home-cage activity, open-field, and passive avoidance tests.

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Wada, Yumiko; Furuse, Tamio; Yamada, Ikuko; Masuya, Hiroshi; Kushida, Tomoko; Shibukawa, Yoko; Nakai, Yuji; Kobayashi, Kimio; Kaneda, Hideki; Gondo, Yoichi; Noda, Tetsuo; Shiroishi, Toshihiko; Wakana, Shigeharu

2010-01-01

To establish the cutoff values for screening ENU-induced behavioral mutations, normal variations in mouse behavioral data were examined in home-cage activity (HA), open-field (OF), and passive-avoidance (PA) tests. We defined the normal range as one that included more than 95% of the normal control values. The cutoffs were defined to identify outliers yielding values that deviated from the normal by less than 5% for C57BL/6J, DBA/2J, DBF(1), and N(2) (DXDB) progenies. Cutoff values for G1-phenodeviant (DBF(1)) identification were defined based on values over +/- 3.0 SD from the mean of DBF(1) for all parameters assessed in the HA and OF tests. For the PA test, the cutoff values were defined based on whether the mice met the learning criterion during the 2nd (at a shock intensity of 0.3 mA) or the 3rd (at a shock intensity of 0.15 mA) retention test. For several parameters, the lower outliers were undetectable as the calculated cutoffs were negative values. Based on the cutoff criteria, we identified 275 behavioral phenodeviants among 2,646 G1 progeny. Of these, 64 were crossed with wild-type DBA/2J individuals, and the phenotype transmission was examined in the G2 progeny using the cutoffs defined for N(2) mice. In the G2 mice, we identified 15 novel dominant mutants exhibiting behavioral abnormalities, including hyperactivity in the HA or OF tests, hypoactivity in the OF test, and PA deficits. Genetic and detailed behavioral analysis of these ENU-induced mutants will provide novel insights into the molecular mechanisms underlying behavior.

Comparison of 6-thioguanine-resistant mutation and sister chromatid exchanges in Chinese hamster V79 cells with forty chemical and physical agents

International Nuclear Information System (INIS)

Nishi, Y.; Hasegawa, M.M.; Taketomi, M.; Ohkawa, Y.; Inui, N.

1984-01-01

The induction of sister chromatid exchanges (SCE) and mutation at the hypoxanthine-guanine phosphoribosyl transferase locus and toxicities of 40 different chemical and physical agents were examined on Chinese hamster V79 cells. These agents included mono-, di-, tri-, and polyfunctional alkylating agents, intercalators, gamma-rays, and UV light irradiation. Mutation was measured as resistance to 6-thioguanine and toxicity as loss of cell-plating efficiency. SCE were examined 29 hr after treatment. With the agents examined, a highly positive correlation existed between SCE-inducing and mutagenic potencies, when expressed as increase in the number per a unit dose over the control values. But the great difference of the ratios of mutagenic potencies versus SCE-inducing potencies among agents was observed, the maximal difference in the ratios being about 200-fold. The agents that showed the higher values of the ratio (agents producing more mutations than SCE) were bleomycin, cobalt-60 gamma-rays, all ethylating agents (N-ethyl-N-nitrosourea, N-ethyl-N'-nitro-N-nitrosoguanidine, ethyl methanesulfonate, and diethylsulfate), N-propyl-N-nitrosourea, N-butyl-N-nitrosourea, isopropyl methanesulfonate, intercalating acridine compounds (2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]-acridine X 2HCl and 2-methoxy-6-chloro-9-[3-(chloroethyl)-aminopropylamino]acridine 2HCl) and UV light at 254 nm

Evaluation of the immunological cellular response of Cebus apella exposed to the carcinogen N-methyl-N-nitrosourea and treated with CANOVA®.

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Feio, Danielle Cristinne Azevedo; Muniz, José Augusto Pereira Carneiro; Montenegro, Raquel Carvalho; Burbano, Rommel Rodriguez; De Brito Junior, Lacy Cardoso; De Lima, Patrícia Danielle Lima

2014-01-01

The immune response modifier Canova® is a homeopathic remedy indicated for patients with depressed immune system, since this drug appears to increase adaptive immunity and induce an immune response against multiple and severe pathological conditions, including cancer. We evaluated the pattern of immune cellular response in non-human primates of the species Cebus apella exposed to N-methyl-N-nitrosourea (MNU) with and without Canova®. Twelve animals were divided into four groups, with three animals each: negative control and three experimental groups, MNU-alone (35 days); MNU (35 days)-plus-Canova® (3 days) and Canova®-alone (3 days). The animals received MNU orally and Canova® by three intravenous injections. Evaluation of the cellular immune response was performed by immunophenotyping of T-lymphocytes (CD4(+), CD8(+)), B-lymphocytes and natural killer cells. Analysis was also performed of the cell cycle. Our results suggest an increase of T-lymphocytes (CD4(+)CD3(+)) only in the Canova® group, while in the MNU-plus-Canova® group only B-lymphocytes increased. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Formation of O2-methylthymine in poly(dA-dT) on methylation with N-methyl-N-nitrosourea and dimethyl sulphate. Evidence that O2-methylthymine does not miscode during DNA synthesis.

Science.gov (United States)

Saffhill, R; Abbott, P J

1978-01-01

The alternating co-polymer has been methylated with either N methyl-N-nitrosourea (MNU) or dimethyl sulphate (DMS) and the levels of the various methylated thymidines (O2-methylthymidine, 3-methylthymidine and O4-methylthymidine) measured. MNU produced all three compounds whereas DMS only produced 3-methylthymidine and O2-methylthymidine at detectable levels. These results have been combined with our earlier results concerning the misincorporation of dGMP with E. coli DNA polymerase using MNU-methylated poly(dA-dT). These results indicate that O2-methylthymidine does not miscode during DNA synthesis. PMID:353735

Integrating Topographic Measures to Explore the Protective Effects of Peonidin Against the N-Methyl-N-Nitrosourea Induced Photoreceptor Degeneration

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Ye Tao

2016-02-01

Full Text Available Background/Aims: The pathphysiological properties of N-Methyl -N -nitrosourea (MNU induced photoreceptor degeneration are similar to the hereditary retinitis pigmentosa (RP. The present study sought to explore the beneficial effects of the peonidin, a common aglycone form of anthocyanin, on the MNU induced photoreceptor degeneration via topographic measurements. Methods: The MNU administrated mouse received peonidin or vehicle injections, and then they were examined by electroretinography (ERG, multi electrode array (MEA, histological and immunohistochemistry studies. Results: The protective effects of peonidin on the MNU administrated retinas were systematically verified and quantified by topographic measures. The peonidin treatment could protect the photoreceptor against the MNU toxicity both functionally and morphologicaly. The most sensitive zone to peonidin therapy was sorted out, indicating that different rescuing kinetics existed between the retinal hemispheres and retinal quadrants. Moreover, the hyperactive spontaneous firing response and the debilitated light induced response in MNU administrated retinas could be partially reversed by peonidin treatment. To our knowledge, this was the first study to explore the pharmacological effects of peonidin on the electrophysiological properties of inner visual signal pathways. Conclusion: The peonidin could ameliorate the MNU induced photoreceptors degeneration and rectify the abnormities in the inner visual signal pathways. Future refinements of the knowledge cast insights into the discovery of a novel treatment for human RP.

A study on the radiation effect on microvasculature of N-methyl-N-Nitrosourea-induced mammary carcinoma in rats

International Nuclear Information System (INIS)

Bae, Sang Hoon; Koh, Kyoung Hwan; Im, Chung Kie; Ha, Sung Hwan; Han, Man Chung

1985-01-01

Mammary carcinoma was induced in rats by intravenous injection of N-methyl-N-Nitrosourea. Microangiography was performed to evaluate the microvascular alterations in mammary carcinoma after irradiation. The tumors were given a single dose of 1,400 rads using Co-60 teletherapy unit with field size of 4 x 4 cm at 40 cm SSD. The dose rate was 147.5 rads per minute. Microangiography was performed prior to irradiation and at one, two, and four weeks following irradiation. The results are as follows: 1. Before irradiation, mammary carcinoma in rats tended to form lobules and the basic vasculature consisted of peripheral vascular pattern with central penetrating vessels. The peripheral vascular pattern was always richer than that of the center. Irregular and tortuous vessels stretched from the periphery into the center of lobule. 2. One week following irradiation, an increase in the number of smaller, tortuous vessels and decreased intervascular distance were observed in the central portion of each lobule. This finding seems to be due to an improved filling of some previously existing but unfilled vessels. This may lead to improved metabolic changes and reoxygenation. 3. Later changes of microvasculature after irradiation are tortuosity, irregularity, narrowing, abrupt tapering, fragmentation, and extravasation. These findings progressed after a lapse of time. 4. The results can be considered as the microangiographic demonstration of the fact that reoxygenation after irradiation is mainly due to dilatation of the collapsed tumor vessels

Uptake, translocation and biotransformation of N-ethyl perfluorooctanesulfonamide (N-EtFOSA) by hydroponically grown plants.

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Zhao, Shuyan; Zhou, Tao; Zhu, Lingyan; Wang, Bohui; Li, Ze; Yang, Liping; Liu, Lifen

2018-04-01

N-ethyl perfluorooctane sulfonamide (N-EtFOSA) is an important perfluorooctanesulfonate (PFOS) precursor (PreFOS) which is used in sulfluramid. The present work studied the uptake, translocation and metabolism of N-EtFOSA in wheat (Triticum aestivum L.), soybean (Glycine max L. Merrill) and pumpkin (Cucurbita maxima L.) by hydroponic exposure. Except for parent N-EtFOSA, its metabolites of perfluorooctane sulfonamide acetate (FOSAA), perfluorooctane sulfonamide (PFOSA), PFOS, perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS) were detected in the roots and shoots of all the three plant species examined. This suggested that plant roots could take up N-EtFOSA from solutions efficiently, and translocate to shoots. A positive correlation was found between root concentration factors (RCFs) of N-EtFOSA and root lipid content. Much higher proportion of N-EtFOSA transformation products in plant tissues than in the solutions suggested that N-EtFOSA could be in vivo metabolized in plant roots and shoots to FOSAA, PFOSA and PFOS, and other additional shorter-chain perfluoroalkane sulfonates (PFSAs), including PFHxS and PFBS. The results suggested that plants had biotransformation pathways to N-EtFOSA that were different than those from microorganisms and animals. This study provides important information about the uptake and metabolism of PreFOSs in plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differences in sensitivity of murine spermatogonia and somatic cells in vivo to sister-chromatid exchange induction by nitrosoureas.

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Morales-Ramírez, P; Cruz-Vallejo, V; Rodríguez-Reyes, R

2001-07-01

Previously published data indicate that spermatogonia (SPG) are less sensitive to a sister-chromatid exchange (SCE) induction for different mutagens. In an earlier study, we have observed that bromodeoxyuridine (BrdU) substituted murine SPG are less sensitive to SCE induction by gamma ray in cells, than bone marrow (BM) and salivary gland (SG) cells in vivo. This was interpreted to mean that SPG are more efficient in DNA repair or are less prone to SCE induction. That the lower induction of SCE could be due to a reduced accessibility of mutagens to the SPG by virtue of a physiological barrier, was discarded by using gamma radiation. The aim of the present study was to establish whether or not there are differences in SCE induction by nitrosoureas among SPG, SG and BM cells with BrdU substituted or unsubstituted DNA. It was observed that SCE induction by methylnitrosourea (MNU) or by ethylnitrosourea (ENU) in SPG was, respectively, five and two times lower than in SG, and ten and three times lower than in BM. In SPG after BrdU incorporation, there was no increase in efficiency of SCE induction; in fact, there was even a slight decrease by exposure to MNU or ENU. BM and SG cells showed an increased efficiency in SCE induction after BrdU incorporation. This implies that SPG are also less sensitive to SCE induction by nitrosoureas, which cause a different kind of damage from previously assayed mutagens.

Effects of atomoxetine on attention in Wistar rats treated with the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4)

NARCIS (Netherlands)

Hauser, J.; Reissmann, A.; Sontag, T.A.; Tucha, Oliver; Lange, K.W.

2017-01-01

The aim of the present study was to assess the effects of the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4), which allows a depletion of noradrenergic terminals in a dose-dependent manner, on attention in rats as measured using the five-choice serial-reaction time task (5CSRTT). In

Immunity against mouse thymus-leukemia antigen (TL) protects against development of lymphomas induced by a chemical carcinogen, N-butyl-N-nitrosourea.

Science.gov (United States)

Tsujimura, Kunio; Obata, Yuichi; Matsudaira, Yasue; Ozeki, Satoshi; Taguchi, Osamu; Nishida, Keiko; Okanami, Yuko; Akatsuka, Yoshiki; Kuzushima, Kiyotaka; Takahashi, Toshitada

2004-11-01

Mouse thymus-leukemia antigens (TL) are aberrantly expressed on T lymphomas in C57BL/6 (B6) and C3H/He (C3H) mice, while they are not expressed on normal T lymphocytes in these strains. When N-butyl-N-nitrosourea (NBU), a chemical carcinogen, was administered orally to B6 and C3H strains, lymphoma development was slower than in T3(b)-TL gene-transduced counterpart strains expressing TL ubiquitously as self-antigens, suggesting that anti-TL immunity may play a protective role. In addition, the development of lymphomas was slightly slower in C3H than in B6, which seems to be in accordance with the results of skin graft experiments indicating that both cellular and humoral immunities against TL were stronger in C3H than B6 mice. The interesting finding that B lymphomas derived from a T3(b)-TL transgenic strain (C3H background) expressing a very high level of TL were rejected in C3H, but not in H-2K(b) transgenic mice (C3H background), raises the possibility that TL-specific effector T cell populations are eliminated and/or energized to a certain extent by interacting with H-2K(b) molecules.

Pyrrolidon carboxypeptidase activities in the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-ovary axes of rats with mammary gland cancer induced by N-methyl nitrosourea.

Science.gov (United States)

Carrera, M P; Ramírez-Expósito, M J; Valenzuela, M T; García, M J; Mayas, M D; Arias de Saavedra, J M; Sánchez, R; Pérez, M C; Martínez-Martos, J M

2005-02-01

Pyrrolidon carboxypeptidase is an omega-peptidase that hydrolyses N-terminal pyroglutamyl residues from biologically active peptides such as gonadotropin-releasing and thyrotrophin-releasing hormones. We previously described a decrease in both rat and human pyrrolidon carboxypeptidase activity with breast cancer, suggesting that gonadotropin-releasing hormone may be an important local intracrine, autocrine and/or paracrine hormonal factor in the pathogenesis of breast cancer while playing a role in the tumoral process. However, the other susceptible substrate of pyrrolidon carboxypeptidase, thyrotrophin-releasing hormone, may also be modified with breast cancer, supporting an association between breast cancer and thyroid disorders. The present work analyses soluble and membrane-bound pyrrolidon carboxypeptidase activities in the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-ovary axes in N-methyl nitrosourea-induced breast cancer in rats. Our aim was to determine the possible relationship between gonadotropin-releasing hormone and thyrotrophin-releasing hormone regulation through pyrrolidon carboxypeptidase activity. We propose that pyrrolidon carboxypeptidase activity dysregulation at various local and systemic levels may participate in the initiation, promotion and progression of breast cancer induced in rat by N-methyl nitrosourea through the increase in gonadotropin-releasing hormone. Since pyrrolidon carboxypeptidase activity also acts on thyrotrophin-releasing hormone, the dysregulation of this enzyme's activity could indirectly affect hypothalamus-pituitary-thyroid axis function, and thus potentially represent a link between the diseases of thyroid and breast cancer.

Nucleotide excision repair modulates the cytotoxic and mutagenic effects of N-n-butyl-N-nitrosourea in cultured mammalian cells as well as in mouse splenocytes in vivo.

Science.gov (United States)

Bol, S A; van Steeg, H; van Oostrom, C T; Tates, A D; Vrieling, H; de Groot, A J; Mullenders, L H; van Zeeland, A A; Jansen, J G

1999-05-01

The butylating agent N-n-butyl-N-nitrosourea (BNU) was employed to study the role of nucleotide excision repair (NER) in protecting mammalian cells against the genotoxic effects of monofunctional alkylating agents. The direct acting agent BNU was found to be mutagenic in normal and XPA mouse splenocytes after a single i.p. treatment in vivo. After 25 and 35 mg/kg BNU, but not after 75 mg/ kg, 2- to 3-fold more hprt mutants were detected in splenocytes from XPA mice than from normal mice. Using O6-alkylguanine-DNA alkyltransferase (AGT)-deficient hamster cells, it was found that NER-deficient CHO UV5 cells carrying a mutation in the ERCC-2 gene were 40% more mutable towards lesions induced by BNU when compared with parental NER-proficient CHO AA8 cells. UV5 cells were 1.4-fold more sensitive to the cytotoxic effects of BNU compared with AA8 cells. To investigate whether this increased sensitivity of NER-deficient cells is modulated by AGT activity, cell survival studies were performed in human and mouse primary fibroblasts as well. BNU was 2.7-fold more toxic for mouse XPA fibroblasts compared with normal mouse fibroblasts. Comparable results were found for human fibroblasts. Taken together these data indicate that the role of NER in protecting rodent cells against the mutagenic and cytotoxic effects of the alkylating agent BNU depends on AGT.

Synthesis, Structural and Antioxidant Studies of Some Novel N-Ethyl Phthalimide Esters

Science.gov (United States)

Chandraju, Siddegowda; Win, Yip-Foo; Tan, Weng Kang; Quah, Ching Kheng; Fun, Hoong-Kun

2015-01-01

A series of N-ethyl phthalimide esters 4(a-n) were synthesized and characterized by spectroscopic studies. Further, the molecular structure of majority of compounds were analysed by single crystal X-ray diffraction studies. The X-ray analysis revealed the importance of substituents on the crystal stability and molecular packing. All the synthesized compounds were tested for in vitro antioxidant activity by DPPH radical scavenging, FRAP and CUPRAC methods. Few of them have shown good antioxidant activity. PMID:25742494

Drosophila mutations at the mei-9 and mus(2)201 loci which block excision of thymine dimers also block induction of unscheluded DNA synthesis by methyl methanesulfonate, ethyl methanesulfonate, N-methyl-N-nitrosourea, UV light and X-rays

International Nuclear Information System (INIS)

Dusenbery, R.L.; McCormick, S.C.; Smith, P.D.

1983-01-01

The mei-9 and mus(2)201 mutants of Drosophila melanogaster were identified as mutagen-sensitive mutants on the basis of larval hypersensitivity to methyl methanesulfonate and characterized as excision repair-deficient on the basis of a greatly reduced capacity to excise thymine dimers from cellular DNA. The high degree of larval cytotoxicity observed with a variety of other chemical and physical agents indicated that these mutants may be unable to excise other important classes of DNA adducts. We have measured the ability of the single mutants and the double mutant combination mei-9;mus(2)201 to perform the resynthesis step in excision repair by means of an autoradiographic analysis of unscheduled DNA synthesis (UDS) induced in a mixed population of primary cells in culture. The 3 strains exhibit no detectable UDS activity in response to applied doses of 1.5-6.0 mM methyl methanesulfonate, 1.0-4.5 nM N-methyl-N-nitrosourea or 10-40 J/m 2 254-nm UV light, dose ranges in which control cells exhibit a strong dose-dependent UDS response. The mei-9 and mei-9;mus(2)201 mutants also have no detectable UDS response to X-ray doses of 300-1.800 rad, whereas the mus(2)201 mutant exhibits a reduced, but dose-dependent, response over this range. These data correlate well with the degree of larval hypersensitivity of the strains and suggest that mutations at both loci block the excision repair of a wide variety of DNA damage prior to the resynthesis step. (orig.)

Synthesis and Crystal Structure of Di-μ-chlorido-bis{chlorido[4-ethyl- N-(pyridin-2-ylmethylidene-κ N)aniline-κ N]mercury(II)}

Science.gov (United States)

Khalaj, M.; Seftejani, F. B.; Ghazanfarpour-Darjani, M.; Lalegani, A.

2017-12-01

The centrosymmetric dinuclear title complex [Hg2Cl4(dip)2] was synthesized using the Schiff base bidentate ligand (E)-4-ethyl- N-(pyridine-2-ylmethylene)benzeneamine ( dip) and mercury(II) chloride salts. It has been characterized by elemental analysis, X-ray diffraction, and UV-Visible and infrared spectroscopic techniques. The X-ray analysis shows that the title compound crystallizes in the monoclinic sp. gr. P21/n, Z = 2 with a = 7.8233(17) Å, b = 15.178(3) Å, c = 12.559(3) Å, β = 97.021(3)°. The Hg(II) ion has a distorted trigonal-bipyramidal coordination environment formed by the bischelating N-heterocyclic ligands, two bridging Cl atoms and one terminal Cl atom.

A new class of nitrosoureas. 4. Synthesis and antitumor activity of disaccharide derivatives of 3,3-disubstituted 1-(2-chloroethyl)-1-nitrosoureas.

Science.gov (United States)

Tsujihara, K; Ozeki, M; Morikawa, T; Kawamori, M; Akaike, Y; Arai, Y

1982-04-01

A series of 33 N-(2-chloroethyl)-N-nitrosocarbamoyl derivatives of N-substituted glycosylamines has been prepared and tested for antitumor activities. The compounds were obtained by reaction of glycosylamines with isocyanate, followed by nitrosation with N2O4. Structure-activity relationships of these trisubstituted nitrosoureas were investigated by varying the N-substituents and disaccharide groups and by comparing them with the corresponding disubstituted analogues. A large number of the nitrosoureas bearing a maltosyl group exhibited strong antitumor activities against leukemia L1210 and Ehrlich ascites carcinoma, and 60-day survivors against leukemia L1210 were found at the optimal dose for these derivatives. In contrast, the lactosyl and the melibiosyl derivatives were almost inactive. The most interesting compound in this series, the 3-isobutyl-3-maltosyl derivative (37), was tested against leukemia L1210 by single and multiple treatment. Its therapeutic ratio (96.3) obtained by multiple treatment is 3 times larger than that (31.5) obtained by single treatment, suggesting a possible clinical utility of 37 by multiple treatment. The favorable effect of a maltosyl moiety in this class of compounds is discussed.

Multicomponent Synthesis of a N-Protected Alpha-Amino Ester: Ethyl 2-((4-Methoxyphenyl)Amino)-3-Phenylpropanoate

Science.gov (United States)

Le Gall, Erwan; Pignon, Antoine

2012-01-01

This laboratory experiment describes the preparation of a N-protected phenylalanine ethyl ester by a zinc-mediated Mannich-like multicomponent reaction between benzyl bromide, "p"-anisidine, and ethyl glyoxylate. The one-step reaction involves the in situ metallation of benzyl bromide into a benzylzinc reagent and its addition onto imine (Barbier…

Spin labeled amino acid nitrosourea derivatives--synthesis and antitumour activity.

Science.gov (United States)

Zheleva, A; Raikov, Z; Ilarionova, M; Todorov, D

1995-01-01

The synthesis of three spin labeled derivatives of N-[N'-(chloroethyl)-N'-nitrosocarbamoyl] amino acids is reported. The new nitrosoureas are obtained by condensation of the corresponding N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl] amino acid with 2,2,6,6-tetramethyl-1-oxyl-4-aminopiperidine using dicyclohexylcarbodiimide. Their chemical structures are confirmed by elemental analysis, IR, MS, and EPR spectroscopy. All newly synthesized compounds showed high antitumour activity against the lymphoid leukemia L1210 in BDF1 mice.

The neurotoxic effects of N-methyl-N-nitrosourea on the electrophysiological property and visual signal transmission of rat's retina.

Science.gov (United States)

Tao, Ye; Chen, Tao; Liu, Bei; Yang, Guo Qing; Peng, Guanghua; Zhang, Hua; Huang, Yi Fei

2015-07-01

The neurotoxic effects of N-methyl-N-nitrosourea (MNU) on the inner retinal neurons and related visual signal circuits have not been described in any animal models or human, despite ample morphological evidences about the MNU induced photoreceptor (PR) degeneration. With the helping of MEA (multielectrode array) recording system, we gained the opportunity to systemically explore the neural activities and visual signal pathways of MNU administrated rats. Our MEA research identified remarkable alterations in the electrophysiological properties and firstly provided instructive information about the neurotoxicity of MNU that affects the signal transmission in the inner retina. Moreover, the spatial electrophysiological functions of retina were monitored and found that the focal PRs had different vulnerabilities to the MNU. The MNU-induced PR dysfunction exhibited a distinct spatial- and time-dependent progression. In contrast, the spiking activities of both central and peripheral RGCs altered synchronously in response to the MNU administration. Pharmacological tests suggested that gap junctions played a pivotal role in this homogeneous response of RGCs. SNR analysis of MNU treated retina suggested that the signaling efficiency and fidelity of inner retinal circuits have been ruined by this toxicant, although the microstructure of the inner retina seemed relatively consolidated. The present study provided an appropriate example of MEA investigations on the toxicant induced pathological models and the effects of the pharmacological compounds on neuron activities. The positional MEA information would enrich our knowledge about the pathology of MNU induced RP models, and eventually be instrumental for elucidating the underlying mechanism of human RP. Copyright © 2015 Elsevier Inc. All rights reserved.

G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea.

Science.gov (United States)

Buchdahl, C; Papon, J; Communal, Y; Bourges, M; Madelmont, J C

1998-12-01

Cystemustine (N'-(2-chloroethyl)-N-(2-(methylsulphonyl)ethyl)-N'-nitrosourea), a new anticancer chloroethylnitrosourea (CENU) is being tested in a phase II clinical trial of disseminated melanoma. The antitumour effect of this drug is mainly due to DNA damage in malignant melanocytes. Recently, we have shown that this damage can induce apoptosis in some melanoma cell lines. In others, apoptosis is not clearly observed, although there is a strong cytostatic effect. In this paper, we have characterized the cytological effect of cystemustine on murine malignant melanocytes (B16 cell line) which are resistant to apoptosis induced by this CENU. The results show that 3 days after cystemustine treatment, these melanocytes had accumulated in phase G2 of the cell cycle. There was then a strong morphological modification during a long cytostatic phase up to 30 days after treatment. During this cytostatic phase, there was uncontrolled DNA synthesis and marked swelling. Also, tyrosinase activity, melanin content and the number of mature melanosomes were greatly increased. These results suggest that when malignant melanocytes are not able to undergo apoptosis after treatment with CENU, they accumulate in G2 and this is followed by enhancement of melanogenesis.

Synthesis and serotonergic activity of substituted 2, N-benzylcarboxamido-5-(2-ethyl-1-dioxoimidazolidinyl)-N, N-dimethyltryptamine derivatives: novel antagonists for the vascular 5-HT(1B)-like receptor.

Science.gov (United States)

Moloney, G P; Martin, G R; Mathews, N; Milne, A; Hobbs, H; Dodsworth, S; Sang, P Y; Knight, C; Williams, M; Maxwell, M; Glen, R C

1999-07-15

The synthesis and vascular 5-HT(1B)-like receptor activity of a novel series of substituted 2, N-benzylcarboxamido-5-(2-ethyl-1-dioxoimidazolidinyl)-N, N-dimethyltryptamine derivatives are described. Modifications to the 5-ethylene-linked heterocycle and to substituents on the 2-benzylamide side chain have been explored. Several compounds were identified which exhibited affinity at the vascular 5-HT(1B)-like receptor of pK(B) > 7.0, up to 100-fold selectivity over alpha(1)-adrenoceptor affinity and 5-HT(2A) receptor affinity, and which exhibited a favorable pharmacokinetic profile. N-Benzyl-3-[2-(dimethylamino)ethyl]-5-[2-(4,4-dimethyl-2, 5-dioxo-1-imidazolidinyl)ethyl]-1H-indole-2-carboxamide (23) was identified as a highly potent, silent (as judged by the inability of angiotensin II to unmask 5-HT(1B)-like receptor-mediated agonist activity in the rabbit femoral artery), and competitive vascular 5-HT(1B)-like receptor antagonist with a plasma elimination half-life of approximately 4 h in dog plasma and with good oral bioavailability. The selectivity of compounds from this series for the vascular 5-HT(1B)-like receptors over other receptor subtypes is discussed as well as a proposed mode of binding to the receptor pharmacophore. It has been proposed that the aromatic ring of the 2, N-benzylcarboxamide group can occupy an aromatic binding site rather than the indole ring. The resulting conformation allows an amine-binding site to be occupied by the ethylamine nitrogen and a hydrogen-bonding site to be occupied by one of the hydantoin carbonyls. The electronic nature of the 2,N-benzylcarboxamide aromatic group as well as the size of substituents on this aromatic group is crucial for producing potent and selective antagonists. The structural requirement on the 3-ethylamine side chain incorporating the protonatable nitrogen is achieved by the bulky 2, N-benzylcarboxamide group and its close proximity to the 3-side chain.

Antinociceptive activities of crude methanolic extract and phases, n-butanolic, chloroformic and ethyl acetate from Caulerpa racemosa (Caulerpaceae

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Everton T. Souza

Full Text Available In this study, we attempted to identify the possible antinociceptive actions of n-butanolic phase, chloroformic phase, ethyl acetate phase and crude methanolic extract obtained from Caulerpa racemosa. This seaweed is cosmopolitan in world, mainly in tropical regions. The n-butanolic, chloroformic, ethyl acetate phases and crude methanolic extract, all administered orally in the concentration of 100 mg/kg, reduced the nociception produced by acetic acid by 47.39%, 70.51%, 76.11% and 72.24%, respectively. In the hotplate test the chloroformic and ethyl acetate phase were activite in this models. In the neurogenic phase on formalin test, were observed that crude methanolic extract (51.77%, n-butanolic phase (35.12%, chloroformic phase (32.70% and indomethacin (32.06% were effective in inhibit the nociceptive response. In the inflammatory phase, only the ethyl acetate phase (75.43% and indomethacin (47.83% inhibited significantly the nociceptive response. Based on these data, we can infer that the ethyl acetate phase shows a significant anti-inflammatory profile, whose power has not yet been determined. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s responsible for the antinociceptive action and also to identify other active principles present in Caulerpa racemosa.

DNA damage induced in mouse peritoneal exudate cells after in vivo administration of chemical and physical agents as determined by alkaline elution

International Nuclear Information System (INIS)

Nishi, Yoshisuke; Miyanaga, Kumiko; Sato, Sei-ichi; Inui, Naomichi

1990-01-01

The alkaline elution technique for detecting DNA strand breaks has been applied to the study of DNA damage in mouse peritoneal exudate cells resulting from the in vivo administration of chemical and physical agents. The direct methylating agents methyl methanesulphonate and N-methyl-N-nitrosourea induced extensive breakage in samples taken 2 h after administration. The direct ethylating agents ethyl methanesulphonate and N-ethyl-N-nitrosourea also induced DNA strand breaks, but to a lesser extent than the methylating agents. The indirect methylating agent dimethylnitrosamine showed hardly any effect in this system. A weak but positive response was observed upon treatment with the anti-neoplastic alkylating agent procarbazine hydrochloride. The whole-body irradiation of mice with 60 Co γ-rays also induced DNA strand breaks. The elution profiles for γ-ray irradiation were different from those of alkylating agents, and indicate that alkylating agents produce many more secondary lesions leading to DNA strand breaks than γ-rays. N-methyl-N-nitrosourea produced slightly more DNA strand breaks in mutagen-sensitive mice, which are derived from the CD-1 strain, than in ICR mice. (Author)

DNA damage induced in mouse peritoneal exudate cells after in vivo administration of chemical and physical agents as determined by alkaline elution

Energy Technology Data Exchange (ETDEWEB)

Nishi, Yoshisuke (Japan Tobacco Inc., Yokohama (Japan). Central Research Inst.); Miyanaga, Kumiko; Sato, Sei-ichi (Japan Tobacco Inc., Hatano, Kanagawa (Japan). Toxicology Research Lab.); Inui, Naomichi (Japan Tobacco Inc., Yokohama, Kanagawa (Japan). Pharmaceutical Research Labs.)

1990-01-01

The alkaline elution technique for detecting DNA strand breaks has been applied to the study of DNA damage in mouse peritoneal exudate cells resulting from the in vivo administration of chemical and physical agents. The direct methylating agents methyl methanesulphonate and N-methyl-N-nitrosourea induced extensive breakage in samples taken 2 h after administration. The direct ethylating agents ethyl methanesulphonate and N-ethyl-N-nitrosourea also induced DNA strand breaks, but to a lesser extent than the methylating agents. The indirect methylating agent dimethylnitrosamine showed hardly any effect in this system. A weak but positive response was observed upon treatment with the anti-neoplastic alkylating agent procarbazine hydrochloride. The whole-body irradiation of mice with {sup 60}Co {gamma}-rays also induced DNA strand breaks. The elution profiles for {gamma}-ray irradiation were different from those of alkylating agents, and indicate that alkylating agents produce many more secondary lesions leading to DNA strand breaks than {gamma}-rays. N-methyl-N-nitrosourea produced slightly more DNA strand breaks in mutagen-sensitive mice, which are derived from the CD-1 strain, than in ICR mice. (Author).

Multiple hypersensitivity to mutagens in a cell strain (46BR) derived from a patient with immuno-deficiencies

International Nuclear Information System (INIS)

Teo, I.A.; Arlett, C.F.; Harcourt, S.A.; Priestley, A.; Broughton, B.C.

1983-01-01

46BR is a fibroblast cell strain established from an individual with hypogammaglobulinaemia. The cells are unique in showing hypersensitivity to the lethal effects of a wide range of DNA-damaging agents. Thus they are hypersensitive to #betta#- and 254-nm UV-irradiation and show a limited capacity to repair potentially lethal #betta#-irradiation damage when compared with fibroblasts from normal individuals. A slight hypersensitivity to mitomycin C was also revealed but we were not able to discriminate 46BR from normals with 4-nitroquinoline oxide. The cells were hypersensitive to the alkylating agents, dimethyl sulphate, methyl methanesulphonate, ethyl methanesulphonate, N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea but not N-ethyl-N-nitrosourea. A consideration of the spectra of DNA lesions produced by these alkylating agents together with the sensitivity to ionising radiation and mitomycin C suggests that 46BR cells are defective in a repair step that is common to all agents. We suggest that the cells are defective in DNA polymerisation or ligation. Support for this suggestion comes from the absence of any hypersensitivity to N-ethyl-N-nitrosourea since its major reaction products are not removed by excision pathways that require polymerisation and ligation. (orig.)

O6-alkylguanine-DNA-alkyltransferase activity and nitrosourea sensitivity in human cancer cell lines.

OpenAIRE

Walker, M. C.; Masters, J. R.; Margison, G. P.

1992-01-01

The DNA repair enzyme, O6-alkylguanine-DNA-alkyltransferase (ATase), is thought to be the principal mechanism controlling resistance to nitrosoureas and related alkylating agents. We compared the sensitivities of five human testis and five bladder tumour cell lines to two nitrosoureas (N-nitroso-N-methylurea (MNU) and mitozolomide) with cellular levels of ATase. Enzyme levels ranged from 3 to 206 fmol mg-1 protein (0.1 x 10(4) to 5.1 x 10(4) molecules/cell) in the testis lines and from 11 to ...

O modelo experimental de carcinogênese gástrica induzido por n-methyl-n-nitrosourea em ratos F344 e camundongos C3H é válido para os ratos Wistar? Experimental model of gastric carcinogenesis with N-methyl-N-nitrosourea for F344 rats and C3H mices is valid for Wistar rats?

Directory of Open Access Journals (Sweden)

Lissandro Tarso

2011-03-01

Full Text Available INTRODUÇÃO: O N-metil-N-nitrosourea (MNU tem ação cancerígena direta, induzindo tumores em várias espécies em uma variedade de órgãos, incluindo o estômago de ratos. Tratamento do MNU na água de beber por 25-42 semanas, seletivamente, induz carcinoma gástrico glandular de ratos F344 e camundongos C3H. OBJETIVO: Estabelecer um modelo experimental para indução seletiva de câncer no estômago glandular de ratos Wistar com MNU. MÉTODOS: Um total de 48 ratos Wistar machos com oito semanas, foram utilizados no presente estudo. MNU (Sigma-Aldrich foi dissolvido em DMSO e liberada água potável ad libitum por um período variando de 16 a 70 semanas. Após 16 semanas, quatro ratos foram selecionados aleatoriamente e mortos. Depois, de seis em seis semanas, quatro animais também foram mortos até 70 semanas. RESULTADOS: A taxa de sobrevivência foi superior a 90%. Ocorreu a indução de dois adenocarcinomas, um carcinoma espinocelular e um sarcoma. A incidência de adenocarcinoma gástrico foi de 4,5% (0,5 a 15. CONCLUSÕES: O modelo experimental de carcinogênese gástrica em ratos Wistar, utilizando MNU dissolvido na água, não mostrou viabilidade prática neste estudo, devido à baixa taxa de adenocarcinoma gástrico que ocorreu.BACKGROUND: The N-methyl-N-nitrosourea (MNU is a direct acting carcinogen, inducing tumors in several species in a variety of organs, including stomach of rats. Treatment of MNU in the drinking water for 25-42 weeks selectively induced glandular gastric carcinoma in F344 rats and C3H mice. AIM: To establish an experimental model for selective MNU induction of glandular stomach cancer in Wistar rats. METHODS: A total of 48 males eight-week-old Wistar rats were used in the present study. MNU (Sigma-Aldrich was dissolved in DMSO and provided as the drinking water ad libitum for a period ranging from 16 to 70 weeks. After 16 weeks, four rats were randomly selected and killed. After every six weeks four animals

Bromidotetra?kis?(1H-2-ethyl-5-methyl?imidazole-?N 3)copper(II) bromide

OpenAIRE

Godlewska, Sylwia; Baranowska, Katarzyna; Socha, Joanna; Do??ga, Anna

2011-01-01

The CuII ion in the title compound, [CuBr(C6H10N2)4]Br, is coordinated in a square-based-pyramidal geometry by the N atoms of four imidazole ligands and a bromide anion in the apical site. Both the CuII and Br− atoms lie on a crystallographic fourfold axis. In the crystal, the [CuBr(C6H10N2)4]+ complex cations are linked to the uncoordinated Br− anions (site symmetry overline{4}) by N—H...Br hydrogen bonds, generating a three-dimensional network. The ethyl group ...

Determination of nitrosourea compounds in brain tissue by gas chromatography and electron capture detection.

Science.gov (United States)

Hassenbusch, S J; Colvin, O M; Anderson, J H

1995-07-01

A relatively simple, high-sensitivity gas chromatographic assay is described for nitrosourea compounds, such as BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea] and MeCCNU [1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea], in small biopsy samples of brain and other tissues. After extraction with ethyl acetate, secondary amines in BCNU and MeCCNU are derivatized with trifluoroacetic anhydride. Compounds are separated and quantitated by gas chromatography using a capillary column with temperature programming and an electron capture detector. Standard curves of BCNU indicate a coefficient of variance of 0.066 +/- 0.018, a correlation coefficient of 0.929, and an extraction efficiency from whole brain of 68% with a minimum detectable amount of 20 ng in 5-10 mg samples. The assay has been facile and sensitive in over 1000 brain biopsy specimens after intravenous and intraarterial infusions of BCNU.

Proline analogue of nitrosourea as a new cytotoxic prodrug.

Science.gov (United States)

Stankiewicz-Kranc, Anna; Bielawska, Anna; Bielawski, Krzysztof; Skrzydlewska, Elzbieta

2009-11-01

Carmustine is frequently used as anticancer drug. High toxicity and low selectivity reduces the application of this drug. Though, there is a necessity to find new compounds characterized by similar therapeutic effects but a higher selectivity and safety. As a result, the proline analogue of nitrosourea, N-[N'-(2-bromophenyl)-N'-nitrosocarbamoyl]proline (AC), has been synthesized. The aim of this study was to compare the influence of carmustine and the proline analogue of nitrosourea on the antioxidant abilities of fibroblasts and leukemia cells, MOLT4. It was shown that carmustine as well as AC cause an increase in hydrogen peroxide concentration in normal and neoplastic cells. Incubation with both compounds led to a diminution of the activity of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and reductase. Changes in activity / level of antioxidant parameters were accompanied by augmentation of lipid and oxidative protein modifications. In conclusion, carmustine and AC cause changes in the antioxidative system of normal and MOLT4 cells and are a reason of oxidative stress formation.

Preventive effect of Oenothera rosea on N-methyl-N-nitrosourea- (NMU induced gastric cancer in rats

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Almora-Pinedo Y

2017-12-01

Full Text Available Yuan Almora-Pinedo,1 Jorge Arroyo-Acevedo,2 Oscar Herrera-Calderon,3 Víctor Chumpitaz-Cerrate,4 Renán Hañari-Quispe,5 Aldo Tinco-Jayo,6 Cesar Franco-Quino,4 Linder Figueroa-Salvador7 1Department of Pharmacy, Hospital Nacional Hipólito Unanue, Lima, 2Laboratory of Experimental Pharmacology, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, 3Faculty of Pharmacy and Biochemistry, Universidad Nacional San Luis Gonzaga de Ica, Ica, 4Laboratory of Physiology and Pharmacology, Faculty of Dentistry, Universidad Nacional Mayor de San Marcos, Lima, 5Laboratory of Animal Physiology, Universidad Andina Néstor Cáceres Velasquez, Puno, 6Academic Department of Human Medicine, School of Pharmacy and Biochemistry, Universidad Nacional San Cristóbal de Huamanga, Ayacucho, 7School of Medicine, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas, Lima, Peru Background: Currently, gastric cancer (GC is considered a public health problem worldwide. Using medicinal plants for the prevention of chronic diseases such as cancer constitutes new alternatives in traditional medicine. Oenothera rosea (OR could be an option, but it needs to be evaluated. Aim: The main objective of this study was to evaluate the protective effect of OR extract on N-methyl-N-nitrosourea (NMU-induced GC in rats. Methods: In total, 80 male Holtzman rats were randomized into five groups. Group A received the saline solution (5mL/kg, group B received NMU 500 μg/kg (cancer inductor by oral administration for 16 weeks, and groups C, D, and E were treated with OR extract (100, 200, and 300 mg/kg, respectively and NMU in order to evaluate the preventive effect on cancer induced by NMU for 16 weeks. Blood and histological samples of stomachs were collected to determine histopathological, biochemical, and hematological parameters between different experimental groups. Results: Groups C, D, and E presented less histopathological changes such as anaplastic and

Influence of ethyl-trinexapac on 15N accumulation and distribution and on highland rice yield

International Nuclear Information System (INIS)

Alvarez, Rita de Cassia Felix; Crusciol, Carlos Alexandre Costa; Alvarez, Angela Cristina Camarim; Trivelin, Paulo Cesar Ocheuze; Rodrigues, Joao Domingos

2007-01-01

The high rice grain yields ensured by sprinkler irrigation have encouraged the use of higher fertilizer doses, mainly the nitrogen fertilizers. However, an improper management of nitrogen fertilization may result in plant lodging. Application of plant regulators may redirect assimilates to grain production while limiting the vegetative growth. This study aimed to: evaluate the influence of the growth regulator Ethyl-trinexapac on plant growth parameters and on 15 N accumulation and distribution in the whole plant and plant components, and determine the contribution of nitrogen taken up in different developmental stages in panicle formation, yield components and rice yield. The experiment was carried out under controlled greenhouse conditions. The treatments consisted of application or not of a plant growth regulator (0 and 200 g active ingredient ha-1 of ethyl-trinexapac) at four plant development stages (beginning to end of tillering; end of tillering and flower differentiation; flower differentiation to flowering; flowering until physiological maturation). The experimental design was arranged in random blocks, in a 2 x 4 factorial scheme, with three replications. The plants were placed in a group of 48 pots. In a group of 24 pots with nutrient solution containing 15 NH 4 SO 4 , plants were collected and separated in parts in the beginning of each pre-established plant development stage and at the end of each stage. In a second group (24 pots), pre-labeled plants were left to grow in nutrient solution with 14 NH 4 SO 4 and harvested at the end of each cycle in order to access 15 N redistribution.. The growth regulator reduced plant height and 15 N accumulation in the panicle and promoted redistribution of the absorbed 15 N, and increased accumulated 15 N in root, stem+sheats and leaves. The contribution of absorbed 15 N to panicle formation in each stage increased with the plant development, though in a lower proportion in the presence of the growth regulator

Modulation of T-Cell Activation in an Experimental Model of Mammary Carcinoma

Science.gov (United States)

1999-07-01

nitrosourea (MNU) mutagenesis system suggested that rejection of SM1 might protect against subsequent mutagenic treatment. However, those studies suffered...R.C., R.C. Osborn, S.M. Swanson, R. Sakthivel, S.I. Hwang, S. Miyamoto, and S. Nandi. 1992. Incidence of c-Ki-ras activation in N-methyl-N- nitrosourea ...against melanocyte antigens (36, 37). Genes encod- Our previous studies have revealed that tumor rejection ing proteins associated with pigment synthesis

Crystal structure of (2E,3E-N2,N3-bis(3-ethyl-[1,1′-biphenyl]-4-ylbutane-2,3-diimine

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Yan Zhao

2015-04-01

Full Text Available In the title compound, C32H32N2, synthesized by the condensation reaction of 2-ethyl-4-phenylaniline and 2,3-butanedione, the conformation about the C=N bonds is E and the substituted biphenyl units are trans to one another. In the two biphenyl ring systems, the planes of the two rings are inclined to one another by 25.25 (19 and 28.01 (19°. The planes of the ethyl-substituted benzene rings are inclined to one another by 20.23 (19° and to the mean plane of the butane-2,3-diimine unit [maximum deviation = 0.014 (4 Å] by 83.19 (19 and 63.38 (19°. In the crystal, molecules are linked by C—H...π interactions, forming sheets lying parallel to (101.

Synthesis of high specific activity tritium-labelled chloroethylcyclohexylnitrosourea and its application to the study of DNA modification

International Nuclear Information System (INIS)

Siew, E.L.; Habraken, Yvette; Ludlum, D.B.

1991-01-01

A small-scale synthesis of high specific activity, N-(2-chloro-2-[ 3 H-ethyl)-N'-cyclohexyl-N-nitrosourea ([ 3 H]-CCNU) has been accomplished from tritium-labelled ethanolamine. The product is pure by TLC and HPLC analysis and has been used successfully to modify DNA. The overall yield on radioactivity including losses in HPLC purification is approximately 4 percent. The availability of this tritium-labelled compound makes studies of DNA repair and of cellular resistance to N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea possible. (author)

Biocatalytic Asymmetric Synthesis of (1R, 2S)-N-Boc-vinyl-ACCA Ethyl Ester with a Newly Isolated Sphingomonas aquatilis.

Science.gov (United States)

Zhu, Shaozhou; Shi, Ying; Zhang, Xinyu; Zheng, Guojun

2018-02-01

1-amino cyclopropane-1-carboxylic acid (ACCA) and its derivatives are essential pharmacophoric unit that widely used in drug research and development. Specifically, (1R, 2S)-N-Boc-vinyl-ACCA ethyl ester (vinyl-ACCA) is a key chiral intermediate in the synthesis of highly potent hepatitis C virus (HCV) NS3/4A protease inhibitors such as asunaprevir and simeprevir. Developing strategies for the asymmetric synthesis of vinyl-ACCA is thus extremely high demand. In this study, 378 bacterial strains were isolated from soil samples using N-Boc-vinyl-ACCA ethyl ester as the sole carbon source and were screened for esterase activity. Fourteen of which worked effectively for the asymmetric synthesis of (1R, 2S)-N-Boc-1-vinyl ACCA ethyl ester. The strain CY-2, identified as Sphingomonas aquatilis, which showed the highest stability and enantioselectivity was selected as whole cell biocatalyst for further study. A systematic study of all factors influencing the enzymatic hydrolysis was performed. Under optimized conditions, resolution of rac-vinyl-ACCA to (1R, 2S)-N-Boc-1-vinyl ACCA ethyl ester with 88.2% ee and 62.4% conversion (E = 9) was achieved. Besides, S. aquatilis was also used to transform other 10 different substrates. Notably, it was found that 7 of them could be stereoselectively hydrolyzed, especially for (1R,2S)-1-amino-vinyl-ACCA ethyl ester hydrochloride (99.6% ee, E>200). Our investigations provide a new efficient whole cell biocatalyst for resolution of ACCA and might be developed for industry application.

Synthesis of high specific activity tritium-labelled chloroethylcyclohexylnitrosourea and its application to the study of DNA modification

Energy Technology Data Exchange (ETDEWEB)

Siew, E.L. (State Univ. of New York, Albany, NY (USA). Dept. of Chemistry); Habraken, Yvette; Ludlum, D.B. (Massachusetts Univ., Worcester, MA (USA). Medical School)

1991-02-01

A small-scale synthesis of high specific activity, N-(2-chloro-2-{sup 3}H-ethyl)-N'-cyclohexyl-N-nitrosourea ({sup 3}H-CCNU) has been accomplished from tritium-labelled ethanolamine. The product is pure by TLC and HPLC analysis and has been used successfully to modify DNA. The overall yield on radioactivity including losses in HPLC purification is approximately 4 percent. The availability of this tritium-labelled compound makes studies of DNA repair and of cellular resistance to N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea possible. (author).

40 CFR 721.9672 - Amides, tall-oil fatty, N-[2-[2-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide...

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amides, tall-oil fatty, N-[2-[2... Significant New Uses for Specific Chemical Substances § 721.9672 Amides, tall-oil fatty, N-[2-[2-hydroxyethyl... identified as amides, tall-oil fatty, N-[2-[2-hydroxyethyl)amino]ethyl], reaction products with sulfur...

Characterization of phospholipase C gamma enzymes with gain-of-function mutations.

Science.gov (United States)

Everett, Katy L; Bunney, Tom D; Yoon, Youngdae; Rodrigues-Lima, Fernando; Harris, Richard; Driscoll, Paul C; Abe, Koichiro; Fuchs, Helmut; de Angelis, Martin Hrabé; Yu, Philipp; Cho, Wohnwa; Katan, Matilda

2009-08-21

Phospholipase C gamma isozymes (PLC gamma 1 and PLC gamma 2) have a crucial role in the regulation of a variety of cellular functions. Both enzymes have also been implicated in signaling events underlying aberrant cellular responses. Using N-ethyl-N-nitrosourea (ENU) mutagenesis, we have recently identified single point mutations in murine PLC gamma 2 that lead to spontaneous inflammation and autoimmunity. Here we describe further, mechanistic characterization of two gain-of-function mutations, D993G and Y495C, designated as ALI5 and ALI14. The residue Asp-993, mutated in ALI5, is a conserved residue in the catalytic domain of PLC enzymes. Analysis of PLC gamma 1 and PLC gamma 2 with point mutations of this residue showed that removal of the negative charge enhanced PLC activity in response to EGF stimulation or activation by Rac. Measurements of PLC activity in vitro and analysis of membrane binding have suggested that ALI5-type mutations facilitate membrane interactions without compromising substrate binding and hydrolysis. The residue mutated in ALI14 (Tyr-495) is within the spPH domain. Replacement of this residue had no effect on folding of the domain and enhanced Rac activation of PLC gamma 2 without increasing Rac binding. Importantly, the activation of the ALI14-PLC gamma 2 and corresponding PLC gamma 1 variants was enhanced in response to EGF stimulation and bypassed the requirement for phosphorylation of critical tyrosine residues. ALI5- and ALI14-type mutations affected basal activity only slightly; however, their combination resulted in a constitutively active PLC. Based on these data, we suggest that each mutation could compromise auto-inhibition in the inactive PLC, facilitating the activation process; in addition, ALI5-type mutations could enhance membrane interaction in the activated state.

Non-alcoholic fatty liver disease in mice with heterozygous mutation in TMED2.

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Wenyang Hou

Full Text Available The transmembrane emp24 domain/p24 (TMED family are essential components of the vesicular transport machinery. Members of the TMED family serve as cargo receptors implicated in selection and packaging of endoplasmic reticulum (ER luminal proteins into coatomer (COP II coated vesicles for anterograde transport to the Golgi. Deletion or mutations of Tmed genes in yeast and Drosophila results in ER-stress and activation of the unfolded protein response (UPR. The UPR leads to expression of genes and proteins important for expanding the folding capacity of the ER, degrading misfolded proteins, and reducing the load of new proteins entering the ER. The UPR is activated in non-alcoholic fatty liver disease (NAFLD in human and mouse and may contribute to the development and the progression of NAFLD. Tmed2, the sole member of the vertebrate Tmed β subfamily, exhibits tissue and temporal specific patterns of expression in embryos and developing placenta but is ubiquitously expressed in all adult organs. We previously identified a single point mutation, the 99J mutation, in the signal sequence of Tmed2 in an N-ethyl-N-nitrosourea (ENU mutagenesis screen. Histological and molecular analysis of livers from heterozygous mice carrying the 99J mutation, Tmed299J/+, revealed a requirement for TMED2 in liver health. We show that Tmed299J/+ mice had decreased levels of TMED2 and TMED10, dilated endoplasmic reticulum membrane, and increased phosphorylation of eIF2α, indicating ER-stress and activation of the UPR. Increased expression of Srebp1a and 2 at the newborn stage and increased incidence of NAFLD were also found in Tmed299J/+ mice. Our data establishes Tmed299J/+ mice as a novel mouse model for NAFLD and supports a role for TMED2 in liver health.

N-[2-(maleimido)ethyl]-3-(trimethylstannyl)benzamide, a molecule for radiohalogenation of proteins and peptides

DEFF Research Database (Denmark)

Aneheim, Emma; Foreman, Mark R StJ; Jensen, Holger

2015-01-01

In this work a new coupling reagent, N-[2-(maleimido)ethyl]-3-(trimethylstannyl)benzamide, for radiohalogenation has been synthesized and characterized. The reagent is intended to either be attached to reduced disulfide bridges of proteins (making the halogenation site-specific) or to free termin...

Preparation of N(1-ethyl-2-pyrrolidyl-methyl)2-methoxy-4-iodo-125I-5-ethyl sulfonyl benzamide: a radioligand for the radioimmunoassay of sulpiride-related compounds

International Nuclear Information System (INIS)

Cardoso, M.T.; Pradelles, P.

1982-01-01

The preparation of 125 I labelling with a higher specific radioactivity of N(1-ethyl-2-pyrrolidyl-methyl)2-methoxy-5-ethyl sulfonyl benzamide, a potent biological analogue for sulpiride is described. The incorporation of iodine in the molecule was achieved by the substitution of aromatic amino groups via the diazo compound. Binding and immunological parameters of iodinated and tritiated tracers were compared. (author)

Polycomb repressive complex 2 (PRC2 restricts hematopoietic stem cell activity.

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Ian J Majewski

2008-04-01

Full Text Available Polycomb group proteins are transcriptional repressors that play a central role in the establishment and maintenance of gene expression patterns during development. Using mice with an N-ethyl-N-nitrosourea (ENU-induced mutation in Suppressor of Zeste 12 (Suz12, a core component of Polycomb Repressive Complex 2 (PRC2, we show here that loss of Suz12 function enhances hematopoietic stem cell (HSC activity. In addition to these effects on a wild-type genetic background, mutations in Suz12 are sufficient to ameliorate the stem cell defect and thrombocytopenia present in mice that lack the thrombopoietin receptor (c-Mpl. To investigate the molecular targets of the PRC2 complex in the HSC compartment, we examined changes in global patterns of gene expression in cells deficient in Suz12. We identified a distinct set of genes that are regulated by Suz12 in hematopoietic cells, including eight genes that appear to be highly responsive to PRC2 function within this compartment. These data suggest that PRC2 is required to maintain a specific gene expression pattern in hematopoiesis that is indispensable to normal stem cell function.

New method to measure the carbamoylating activity of nitrosoureas by electron paramagnetic resonance spectroscopy.

Science.gov (United States)

Gadzheva, V; Ichimori, K; Raikov, Z; Nakazawa, H

1997-08-01

A new method for measuring the carbamoylating activity of nitrosoureas and isocyanates using electron paramagnetic resonance (EPR) spectroscopy is described. The extent and time course of carbamoylation reaction of chloroethyl isocyanate and a series of 9 nitrosoureas toward amino group of 4-amino-2,2,6,6-tetramethyl-piperidine-1-oxyl were examined with both the EPR method and the HPLC method which has been proposed by Brubaker et al. [Biochem. Pharmacol. 35:2359 (1986)]. Spin-labeled nitrosoureas we synthesized are included in this study since they have less toxicity or more efficiency than commercially available drug in some cases. The concentration of carbamoylated product was easily determined with the EPR spectra. There is a very high correlation (r = 0.982, t = 2.58, N = 10, p nitrosoureas showed lower carbamoylating activity than non-labeled analogues. The carbamoylating activity for these nitrosourea depended on the reactivity of isocyanate intermediate and almost independent of their half life. This rapid and simple EPR method is suitable for the detailed investigation of the rate and extent of carbamoylation reaction.

(Tris{2-[(5-hydroxypyridin-2-yl-κNmethylideneimino-κN]ethyl}aminezinc dinitrate

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Maksym Seredyuk

2011-12-01

Full Text Available In the complex cation of the title compound, [Zn(C24H27N7O3](NO32, the tripodal tris{[2-(5-hydroxypyridin-2-ylmethylideneimino]ethyl}amine ligand is coordinated to the Zn atom through the three pyridine and three imino N atoms. The coordination sphere of the Zn atom is based on an octahedron with a significant distortion towards trigonal prismatic, the twist angle being 45.58 (9°. The crystal packing is formed by L and D antipodes arranged in layers disposed parallel to the b axis. Strong O—H...O hydrogen bonding exists between the hydroxy groups of the ligand and the nitrate anion.

A high protein moderate carbohydrate diet fed at discrete meals reduces early progression of N-methyl-N-nitrosourea-induced breast tumorigenesis in rats

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Singletary Keith W

2010-01-01

Full Text Available Abstract Breast cancer is the most prevalent cancer in American women. Dietary factors are thought to have a strong influence on breast cancer incidence. This study utilized a meal-feeding protocol with female Sprague-Dawley rats to evaluate effects of two ratios of carbohydrate:protein on promotion and early progression of breast tissue carcinomas. Mammary tumors were induced by N-methyl-N-nitrosourea (MNU at 52 d of age. Post-induction, animals were assigned to consume either a low protein high carbohydrate diet (LPHC; 15% and 60% of energy, respectively or a high protein moderate carbohydrate diet (HPMC; 35% and 40% of energy, respectively for 10 wk. Animals were fed 3 meals/day to mimic human absorption and metabolism patterns. The rate of palpable tumor incidence was reduced in HPMC relative to LPHC (12.9 ± 1.4%/wk vs. 18.2 ± 1.3%/wk. At 3 wk, post-prandial serum insulin was larger in the LPHC relative to HPMC (+136.4 ± 33.1 pmol/L vs. +38.1 ± 23.4 pmol/L, while at 10 wk there was a trend for post-prandial IGF-I to be increased in HPMC (P = 0.055. There were no differences in tumor latency, tumor surface area, or cumulative tumor mass between diet groups. The present study provides evidence that reducing the dietary carbohydrate:protein ratio attenuates the development of mammary tumors. These findings are consistent with reduced post-prandial insulin release potentially diminishing the proliferative environment required for breast cancer tumors to progress.

Quantification of four major metabolites of embryotoxic N-methyl- and N-ethyl-2-pyrrolidone in human urine by cooled-injection gas chromatography and isotope dilution mass spectrometry.

Science.gov (United States)

Schindler, Birgit K; Koslitz, Stephan; Meier, Swetlana; Belov, Vladimir N; Koch, Holger M; Weiss, Tobias; Brüning, Thomas; Käfferlein, Heiko U

2012-04-17

N-Methyl- and N-ethyl-2-pyrollidone (NMP and NEP) are frequently used industrial solvents and were shown to be embryotoxic in animal experiments. We developed a sensitive, specific, and robust analytical method based on cooled-injection (CIS) gas chromatography and isotope dilution mass spectrometry to analyze 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI), two newly identified presumed metabolites of NEP, and their corresponding methyl counterparts (5-HNMP, 2-HMSI) in human urine. The urine was spiked with deuterium-labeled analogues of these metabolites. The analytes were separated from urinary matrix by solid-phase extraction and silylated prior to quantification. Validation of this method was carried out by using both, spiked pooled urine samples and urine samples from 56 individuals of the general population with no known occupational exposure to NMP and NEP. Interday and intraday imprecision was better than 8% for all metabolites, while the limits of detection were between 5 and 20 μg/L depending on the analyte. The high sensitivity of the method enables us to quantify NMP and NEP metabolites at current environmental exposures by human biomonitoring.

Novel N-benzoyltyramines of Swinglea glutinosa (Rutaceae); Novas N-benzoiltiraminas de Swinglea glutinosa (Rutaceae).

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, Cristovam do Nascimento; Santos, Djalma A.P. dos; Malaquias, Karla da Silva; Lima, Murilo Marinho de Castro; Silva, Maria Fatima das Gracas Fernandes da; Fernandes, Joao Batista; Vieira, Paulo Cezar, E-mail: dmfs@ufscar.br [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica

2012-07-01

Phytochemical studies of the leaves and fruits have led to the identification of the known amides (E)-N-methyl-cinnamamide, N-benzoyltyramine, N-benzoyl-O-geranyl tyramine, N-benzoyl-O-(4-acetoxyl)-geranyl tyramine, in addition to the new N-{l_brace}2-[4-(butoxyl-3-one)phenyl]ethyl{r_brace}benzamide, N-{l_brace}2-[4-(2,3-dihydroxy-2-methyl-butoxylanal)phenyl]ethyl{r_brace}benzamide, N-{l_brace}2-[4-(2,3-dihydroxy-2-methyl-butoxyloic) phenyl]ethyl{r_brace}benzamide, N-benzoyl-O-(4-acetoxyl-6,7-epoxy)-geranyltyramine, N-benzoyl-O-(4-acetoxyl-6,7-dihydroxy)-geranyltyramine and N-benzoyl-O-(6-acetoxyl-4,7-dihydroxy)-geranyltyramine. The isolated compounds clearly point to Swinglea phytochemical affinities with other Aurantioideae species. (author)

Thermal decomposition synthesis of nanorods bismuth sulphide from bismuth N-ethyl cyclohexyl dithiocarbamate complex

International Nuclear Information System (INIS)

Abdullah, Nurul Hidayah; Zainal, Zulkarnain; Silong, Sidik; Tahir, Mohamed Ibrahim Mohamed; Tan, Kar-Ban; Chang, Sook-Keng

2016-01-01

Highlights: • Bismuth N-ethyl cyclohexyl dithiocarbamate was used as single source precursor. • No surfactant was used in the preparation of Bi_2S_3 nanorods. • Pure phase orthorhombic Bi_2S_3 is obtained. • Bismuth sulphide with an average atomic ratio of Bi:S close to 2:3 is obtained. - Abstract: Nanorods of bismuth sulphide were prepared by thermal decomposition of bismuth N-ethyl cyclohexyl dithiocarbamate at different calcination duration. X-ray diffraction (XRD) analysis shows that at 400 °C, the precursor was fully decomposed to orthorhombic bismuth sulphide after 2 h of calcination. Besides, calcination duration does not affect the existence of Bi_2S_3 phase. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses reveal that Bi_2S_3 nanorods with an average width ranging from 29–36 nm were obtained. Energy dispersive X-ray (EDX) analysis confirmed the atomic ratio of Bi and S close to 2:3, giving a possible composition of Bi_2S_3. Direct band gap energy of Bi_2S_3 decreases from 1.83 eV to 1.54 eV as calcination time increases.

Morphological mutations induced by gamma rays, ethylene imine and N-nitroso-N-ethyl urea in lentil (Lens culinaris medik.)

International Nuclear Information System (INIS)

Solanki, I.S.; Sharma, B.

2003-01-01

Dry and healthy seeds of a large seeded lentil cv, 'Precoz Selection', were treated with three doses each of gamma rays, ethylene imine (EI) and N-nitroso-N-ethyl urea (NEU). Based on the frequency of morphological mutations, the mutagens were arranged in the order: NEU > EI >. Gamma rays and dose-dependent relationship was observed in the case of gamma rays (5 kR 1 damage groups induced morphological mutations in the order: HH > HL > LH > LL. The morphological mutations included changes for growth habit, foliage, plant height and maturity and flowering behaviour. A mild relative mutagenic specificity and differences in mutability of genes for different traits were observed, In general the spectrum of morphological mutations was not influenced by the groups of M 1 damage, except that some mutation types occurred more frequently, than others in certain groups. (author)

Evaluation of genotoxic activity of maleic hydrazide, ethyl methane sulfonate, and N-nitroso diethylamine in Tradescantia

OpenAIRE

Alvarez-Moya Carlos; Santerre-Lucas Anne; Zúñiga-González Guillermo; Torres-Bugarín Olivia; Padilla-Camberos Eduardo; Feria-Velasco Alfredo

2001-01-01

Objective. To assess the genotoxic activity of N-nitroso diethylamine (NDEA), maleic hydrazide (MH), and ethyl methane sulfonate (EMS) using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430). Material and Methods. Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine ...

Analysis of the expression level and methylation of tumor protein p53, phosphatase and tensin homolog and mutS homolog 2 in N-methyl-N-nitrosourea-induced thymic lymphoma in C57BL/6 mice.

Science.gov (United States)

Huo, Xueyun; Li, Zhenkun; Zhang, Shuangyue; Li, Changlong; Guo, Meng; Lu, Jing; Lv, Jianyi; Du, Xiaoyan; Chen, Zhenwen

2017-10-01

Tumorigenesis is often caused by somatic mutation or epigenetic changes in genes that regulate aspects of cell death, proliferation and survival. Although the functions of multiple tumor suppressor genes have been well studied in isolation, how these genes cooperate during the progression of a single tumor remains unclear in numerous cases. The present study used N-methyl-N-nitrosourea (MNU), one of the most potent mutagenic nitrosourea compounds, to induce thymic lymphoma in C57BL/6J mice. Subsequently, the protein expression levels of phosphatase and tensin homolog (PTEN), transformation protein 53 and mutS homolog 2 (MSH2) were evaluated concomitantly in the thymus, liver, kidney and spleen of MNU-treated mice by western blotting. To determine whether changes in expression level were due to aberrant epigenetic regulation, the present study further examined the methylation status of each gene by MassARRAY analysis. During the tumorigenesis process of an MNU-induced single thymic lymphoma, the expression level of PTEN was revealed to be reduced in thymic lymphoma samples but not in normal or non-tumor thymus tissue samples. Furthermore, a marked reduction of P53 expression levels were demonstrated in thymic lymphomas and spleens with a metastatic tumor. Conversely, MSH2 upregulation was identified only in liver, kidney, and spleen samples that were infiltrated by thymic lymphoma cells. Furthermore, the present study revealed that a number of 5'-C-phosphate-G-3' sites located in the promoter of aberrantly expressed genes had significantly altered methylation statuses. These results improve the understanding of the course of mutagen-induced cancer, and highlight that epigenetic regulation may serve an important function in cancer.

Solvent extraction of aromatic sulfur compounds from n-heptane using the 1-ethyl-3-methylimidazolium tricyanomethanide ionic liquid

International Nuclear Information System (INIS)

Królikowski, Marek; Walczak, Klaudia; Domańska, Urszula

2013-01-01

Highlights: • LLE data for (EMIMTCM + thiophene/benzothiophene + n-heptane) were determined. • High S and β for the extraction of thiophene/benzothiophene from n-heptane was found. • Results of S and β were compared with available literature. • The NRTL model satisfactorily correlates the LLE data. -- Abstract: The ionic liquid 1-ethyl-3-methylimidazolium tricyanomethanide ([EMIM][TCM]) has been tested as a solvent for the separation of sulfur compounds from aliphatic hydrocarbon. Liquid–liquid phase equilibrium data have been determined for ternary systems containing the ionic liquid, thiophene or benzothiophene and n-heptane. The influence of temperature on the separation of thiophene from n-heptane was determined. High solubility of sulfur compounds and practical immiscibility of aliphatic hydrocarbon in ionic liquid have been found. The values of selectivity and solute distribution ratios have been calculated for all systems and compared with literature data for other 1-ethyl-3-methylimidazolium-based ionic liquids. High values of selectivity were obtained. The experimental data were correlated using the NRTL equation, and the binary interaction parameters have been reported. The phase equilibria diagrams for the ternary mixtures including the experimental and calculated tie-lines have been presented

Effects of thermal and fast neutrons and of ENU on generations M3 and M4 of Lens culinaris (medicus)

International Nuclear Information System (INIS)

Uhlik, J.; Urban, J.

1976-01-01

Plants in which the selection of the most fertile plants had not been made in the preceding generations showed a significantly lower emergence rate in the M3 and M4 generation after an ethyl nitroso urea (ENU) application, in comparison with material treated with neutrons. In the evaluation of the plants obtained after an exposure to the most effective doses in the induction of chlorophyll mutants, significant differences of the average values in relation to the control were found in the M3 generation in the number of seeds per plant after the application of both neutron radiations and ENU. In addition, after the application of thermal neutrons and ENU a significant difference was found in the average values of plant weight. A difference in the overall range of variability in relation to the control was found in plant weight after the application of neutrons and ENU, and in seed weight after the application of ENU and fast neutrons. The differences between the treated plants and controls in the M4 generation plants with fusarium disease were insignificant. The evaluation of the progenies exposed to various doses of the highest mutation effectiveness showed in the M3 generation significant differences (in relation to the control) in the mean values of plant height, seed weight, plant weight, seed proportion in plants, in the bottom-pod insertion level, and in the number of pods set. Despite a considerable attack by fusarium disease, the greatest number of plants having more seeds than 50 was selected in the M4 generation of the material exposed to the dose of 8 fast neutrons (0.95% of plants) while in the control the proportion of highly fertile plants was only 0.05%. The widest range of overall variability in the characteristics under study was found after irradiation with thermal neutrons. From this viewpoint they can be recommended for wide practical utilization. (author)

Effect of temperature on the optical and structural properties of hexadecylamine capped ZnS nanoparticles using Zinc(II) N-ethyl-N-phenyldithiocarbamate as single source precursor

Energy Technology Data Exchange (ETDEWEB)

Onwudiwe, Damian C., E-mail: dconwudiwe@webmail.co.za [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Strydom, Christien [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Oluwafemi, Oluwatobi S., E-mail: oluwafemi.oluwatobi@gmail.com [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag X1, Mthatha (South Africa); Songca, Sandile P. [Faculty of Science, Engineering and Technology, Walter Sisulu University, P.O. Box 19712, Tecoma, East London (South Africa)

2012-12-15

Graphical abstract: Display Omitted Highlights: ► HDA-capped ZnS nanoparticles were synthesized via thermolysis of a single source precursor. ► Zinc(II) N-ethyl-N-phenyldithiocarbamate was used as the single source precursor. ► The growth temperature was varied to study the optical properties of the nanocrystals. ► Change in growth temperature affects the structural properties of the ZnS nanoparticles. ► Hexagonal wurtzite phase was obtained at lower temperatures while cubic sphalerite phase was obtained at higher growth temperatures. -- Abstract: Reported in this work is the synthesis of HDA (hexadecylamine)-capped ZnS nanoparticles by a single source route using Zinc(II) N-ethyl-N-phenyldithiocarbamate as a precursor. By varying the growth temperature, the temporal evolution of the optical properties and morphology of the nanocrystals were investigated. The as-synthesized nanoparticles were characterized using UV–vis absorption and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited quantum confinement in their optical properties with band edge emission at the early stage of the reaction. The XRD showed transition from hexagonal wurtzite phase to cubic sphalerite phase as the growth temperature increases. The TEM image showed that the particles are small and spherical in shape while the HRTEM image confirmed the crystalline nature of the material.

Thermodynamic models for determination of 3-chloro-N-phenylphthalimide solubility in binary solvent mixtures of (acetone, ethyl acetate or 1,4-dioxane + methanol)

International Nuclear Information System (INIS)

Xie, Yong; Shi, Hongwei; Du, Cunbin; Cong, Yang; Wang, Jian; Zhao, Hongkun

2016-01-01

Highlights: • Solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents were determined. • Solubility data were correlated and calculated by five models. • The standard molar enthalpy for the dissolution processes were calculated. - Abstract: The solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents of (acetone + methanol, ethyl acetate + methanol and 1,4-dioxane + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (288.15 to 323.15) K under atmosphere pressure. For the binary systems of (acetone + methanol) and (1,4-dioxane + methanol), the solubility of 3-chloro-N-phenylphthalimide increased with increasing temperature and mass fraction of acetone or 1,4-dioxane; and for the (ethyl acetate + methanol) system, at a given composition of ethyl acetate, the solubility of 3-chloro-N-phenylphthalimide increased with an increase in temperature; nevertheless at the same temperature, they increased at first and then decreased with increasing mass fraction of 1,4-dioxane. At the same temperature and mass fraction of acetone, ethyl acetate or 1,4-dioxane, the solubility of 3-chloro-N-phenylphthalimide was greater in (1,4-dioxane + methanol) than in the other two mixed solvents. The solubility values were correlated by employing the Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, Apelblat–Jouyban–Acree model, Ma model, and Sun model. On the whole, the Ma model and Sun model were proven to provide good representation of the experimental solubility results. Furthermore, the dissolution enthalpies of the dissolution process were calculated. The dissolution process of 3-chloro-N-phenylphthalimide in these mixed solvents is endothermic. The experimental solubility and the models in this study could be helpful in purifying 3-chloro-N-phenylphthalimide.

Organotin(IV complexes derived from N-ethyl-N-phenyldithiocarbamate: Synthesis, characterization and thermal studies

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Jerry O. Adeyemi

2018-05-01

Full Text Available Organotin(IV dithiocarbamate complexes, RSnClL2 and R2SnL2 (R = Me, Bu, Ph, and L = N-ethyl-N-phenyldithiocarbamate, have been synthesized by the reaction of mono- and disubstituted organotin(IV with ammonium dithiocarbamate. The complexes were characterized by elemental analyses, and spectroscopic techniques (1H, 13C NMR and FTIR. The structures of Me2SnL2 and Bu2SnL2 were further established by single crystal X-ray diffraction technique. The crystal structure analysis showed that both complexes (Me2SnL2 and Bu2SnL2 exist as monomers. One of the dithiocarbamate ligands formed a chelate, while the other dithiocarbamate bonded to the central tin atom through one of the sulfur atoms and the second sulfur atom existed as a pendant to form distorted trigonal bipyramidal geometry. The thermal stability of all the complexes was studied using simultaneous thermogravimetry (TG and differential scanning calorimetry (DSC. The TG-DSC results showed that Me2SnL2, BuSnClL2, Bu2SnL2, and PhSnClL2 displayed similar decomposition pathway via isothiocyanate intermediate, while MeSnClL2 and Ph2SnL2 showed decomposition pathways different from the rest of the complexes. All the complexes resulted in SnS as the final product of the thermal decomposition process. Keywords: Organotin, Dithiocarbamate, Crystal structure, Thermal studies

Diet-induced obesity increases the frequency of Pig-a mutant erythrocytes in male C57BL/6J mice.

Science.gov (United States)

Wickliffe, Jeffrey K; Dertinger, Stephen D; Torous, Dorothea K; Avlasevich, Svetlana L; Simon-Friedt, Bridget R; Wilson, Mark J

2016-12-01

Obesity increases the risk of a number of chronic diseases in humans including several cancers. Biological mechanisms responsible for such increased risks are not well understood at present. Increases in systemic inflammation and oxidative stress, endogenous production of mutagenic metabolites, altered signaling in proliferative pathways, and increased sensitivity to exogenous mutagens and carcinogens are some of the potential contributing factors. We hypothesize that obesity creates an endogenously mutagenic environment in addition to increasing the sensitivity to environmental mutagens. To test this hypothesis, we examined two in vivo genotoxicity endpoints. Pig-a mutant frequencies and micronucleus frequencies were determined in blood cells in two independent experiments in 30-week old male mice reared on either a high-fat diet (60% calories from fat) that exhibit an obese phenotype or a normal-fat diet (10% calories from fat) that do not exhibit an obese phenotype. Mice were assayed again at 52 weeks of age in one of the experiments. N-ethyl-N-nitrosourea (ENU) was used as a positive mutation control in one experiment. ENU induced a robust Pig-a mutant and micronucleus response in both phenotypes. Obese, otherwise untreated mice, did not differ from non-obese mice with respect to Pig-a mutant frequencies in reticulocytes or micronucleus frequencies. However, such mice, had significantly higher and sustained Pig-a mutant frequencies (increased 2.5-3.7-fold, p obese mice (based on measurements collected at 30 weeks or 30 and 52 weeks of age). This suggests that obesity, in the absence of exposure to an exogenous mutagen, is itself mutagenic. Environ. Mol. Mutagen. 57:668-677, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Synthesis Of Copoly (2-Hydroxy Ethyl Methacrylate/N-Vinyl Pirrolidone) Hydrogel By Gamma Irradiation And Immobilization Of Ametryne

International Nuclear Information System (INIS)

Erizal

2002-01-01

The synthesis of copoly (2-hydroxy ethyl methacrylate/N-vinyl pirrolidone) hydrogel has been carried out. The 2-hydroxy ethyl methacrylate (HEMA) solution with the concentrations of 40, 50, and 60 % v/v were respectively mixed with N-vinyl pirrolidone (NVP) at a concentration of 5 % v/v with composition of 4:1, homogenized, and bubbled with N 2 .The samples were irradiated by gamma rays at a doses of 5 kGy (dose rate 7.5 kGy/h). The parameters were observed the effect of time soaking (0-32 hours) and temperatures (10-60 oC ) of the hydrogels, the ability of hydrogels to absorb water, the ability of hydrogels for immobilization and released of ametryne and its effects on the kiambang growth. After evaluation, with increasing the concentration of HEMA ( NVP constant), the water absorption and the amount of ametryne released decreased, relatively. With increasing the temperature up to 60 oC and the concentrations of HEMA, the water absorption decreased. The amount of ametryne released from hydrogel affect the growth of kiambang

Spin labelled nitrosoureas and triazenes and their non-labelled clinically used analogues--a comparative study on their physicochemical properties and antimelanomic effects.

Science.gov (United States)

Zheleva, A M; Gadjeva, V G

2001-01-16

Physicochemical properties, such as half life time (tau0.5), alkylating and carbamoylating activity and in vivo antimelanomic effects against B16 melanoma of spin labeled (containing nitroxyl free radical moiety) amino acid nitrosoureas, synthesized in our laboratory, have been studied and compared to those of the antitumor drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU). We have shown that the introduction of amino acid moieties and the replacement of cyclohexylamine with nitroxyl moiety leads to a faster decomposition, higher alkylating, lower carbamoylating activity, better antimelanomic activity and lower general toxicity, when compared to those of CCNU. It was also established that spin labeled triazenes, previously synthesized by us, were more stable in phosphate saline than their nonlabeled analogue, 5-(3,3-dimethyltriazene-1-yl)-imidazole-4-carboxamide (dacarbazine, DTIC). A higher cytotoxicity to B16 melanoma cells than to YAC-1 and lymphocytes was demonstrated for all spin labeled triazenes, in comparison with DTIC. An assumption has been made to explain the lower general toxicity of the spin labeled nitrosoureas compared to that of CCNU. Based on the results presented, we accept that a new trend for synthesis of more selective and less toxic nitrosourea and triazene derivatives as potential antimelanomic drugs might be developed.

The neurotoxic effects of N-methyl-N-nitrosourea on the electrophysiological property and visual signal transmission of rat's retina

Energy Technology Data Exchange (ETDEWEB)

Tao, Ye [Department of Ophthalmology, General Hospital of Chinese PLA, Beijing 100853 (China); Chen, Tao [Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi' an 710032 (China); Liu, Bei [Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi' an (China); Yang, Guo Qing [Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi' an 710032 (China); Peng, Guanghua [Department of Ophthalmology, General Hospital of Chinese PLA, Beijing 100853 (China); Zhang, Hua [Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi' an (China); Huang, Yi Fei [Department of Ophthalmology, General Hospital of Chinese PLA, Beijing 100853 (China)

2015-07-01

The neurotoxic effects of N-methyl-N-nitrosourea (MNU) on the inner retinal neurons and related visual signal circuits have not been described in any animal models or human, despite ample morphological evidences about the MNU induced photoreceptor (PR) degeneration. With the helping of MEA (multielectrode array) recording system, we gained the opportunity to systemically explore the neural activities and visual signal pathways of MNU administrated rats. Our MEA research identified remarkable alterations in the electrophysiological properties and firstly provided instructive information about the neurotoxicity of MNU that affects the signal transmission in the inner retina. Moreover, the spatial electrophysiological functions of retina were monitored and found that the focal PRs had different vulnerabilities to the MNU. The MNU-induced PR dysfunction exhibited a distinct spatial- and time-dependent progression. In contrast, the spiking activities of both central and peripheral RGCs altered synchronously in response to the MNU administration. Pharmacological tests suggested that gap junctions played a pivotal role in this homogeneous response of RGCs. SNR analysis of MNU treated retina suggested that the signaling efficiency and fidelity of inner retinal circuits have been ruined by this toxicant, although the microstructure of the inner retina seemed relatively consolidated. The present study provided an appropriate example of MEA investigations on the toxicant induced pathological models and the effects of the pharmacological compounds on neuron activities. The positional MEA information would enrich our knowledge about the pathology of MNU induced RP models, and eventually be instrumental for elucidating the underlying mechanism of human RP. - Highlights: • We systemically explored the neural activities and visual signal pathways of MNU administrated retinas. • The focal photoreceptors had different vulnerabilities to the MNU administration. �

The neurotoxic effects of N-methyl-N-nitrosourea on the electrophysiological property and visual signal transmission of rat's retina

International Nuclear Information System (INIS)

Tao, Ye; Chen, Tao; Liu, Bei; Yang, Guo Qing; Peng, Guanghua; Zhang, Hua; Huang, Yi Fei

2015-01-01

The neurotoxic effects of N-methyl-N-nitrosourea (MNU) on the inner retinal neurons and related visual signal circuits have not been described in any animal models or human, despite ample morphological evidences about the MNU induced photoreceptor (PR) degeneration. With the helping of MEA (multielectrode array) recording system, we gained the opportunity to systemically explore the neural activities and visual signal pathways of MNU administrated rats. Our MEA research identified remarkable alterations in the electrophysiological properties and firstly provided instructive information about the neurotoxicity of MNU that affects the signal transmission in the inner retina. Moreover, the spatial electrophysiological functions of retina were monitored and found that the focal PRs had different vulnerabilities to the MNU. The MNU-induced PR dysfunction exhibited a distinct spatial- and time-dependent progression. In contrast, the spiking activities of both central and peripheral RGCs altered synchronously in response to the MNU administration. Pharmacological tests suggested that gap junctions played a pivotal role in this homogeneous response of RGCs. SNR analysis of MNU treated retina suggested that the signaling efficiency and fidelity of inner retinal circuits have been ruined by this toxicant, although the microstructure of the inner retina seemed relatively consolidated. The present study provided an appropriate example of MEA investigations on the toxicant induced pathological models and the effects of the pharmacological compounds on neuron activities. The positional MEA information would enrich our knowledge about the pathology of MNU induced RP models, and eventually be instrumental for elucidating the underlying mechanism of human RP. - Highlights: • We systemically explored the neural activities and visual signal pathways of MNU administrated retinas. • The focal photoreceptors had different vulnerabilities to the MNU administration. �

Suzuki coupling reactions catalyzed by poly(N-ethyl-4-vinylpyridinium bromide stabilized palladium nanoparticles in aqueous solution

Directory of Open Access Journals (Sweden)

2008-04-01

Full Text Available InIn this work, it was investigated to use of poly(N-ethyl-4-vinylpyridinium bromide stabilized palladium nanoparticles in the Suzuki reaction between phenylboronic acid and aryl halides in aqueous solution. The nanoparticles were isolated and re-used several times with low loss of activity.

Synthesis and Physical and Chemical Properties of Hypergolic Chemicals such as N,N,N-Trimethylhydrazinium and 1-Ethyl-4-Methyl-1,2,4-Triazolium Salts

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Young-Seok Kim

2015-12-01

Full Text Available Hypergolic chemicals N,N,N-trimethylhydrazinium iodide, [TMH]+[I]−, and 1-ethyl-4-methyl-1,2,4-triazolium iodide, [EMT]+[I]− were firstly synthesized by nucleophilic substitution (SN2. The successful synthesis of hypergolic chemicals [TMH]+[I]− and [EMT]+[I]− was confirmed by IR and 1H-NMR spectroscopy and, GC-mass spectrometry. Subsequently the hypergolic chemicals [TMH]+[X]− (X = CN−, N3−, NO3−, NO2−, ClO4−, AlCl4− were prepared via an ion exchange reaction from [TMH]+[I]− and [EMT]+[I]−, respectively. After that, a mixture of hypergolic chemicals was prepared by dissolving the synthesized hypergolic chemicals in 2-hydroxyethylhydrazine (HOCH2CH2NHNH2. The physical and chemical properties of the mixture such as decomposition temperature (Td, density (d, viscosity (η, and decomposition energy (ΔHd was then evaluated to determine suitability for use as liquid rocket fuels. The ignition delay (ID time of the mixture of hypergolic chemicals with [TMH]+[N3]− and [TMH]+[CN]− using H2O2 as an oxidizer was determined as 55.6 ms and 97.4 ms; respectively. The ID time of the mixture of hypergolic chemicals with [EMT]+[N3]−; [EMT]+[CN]−; [EMT]+[AlCl4]−; and [EMT]+[I]− using H2O2 as an oxidizer was also determined as 18.0 ms; 32.6 ms; 27.6 ms; and 7.96 ms; respectively. The synthesized mixture of hypergolic chemicals could thus be used as a rocket propellant liquid fuel.

Problems in extrapolating genotoxicity data from cellular systems in vitro

Energy Technology Data Exchange (ETDEWEB)

Mohn, G.R.; van Zeeland, A.A.

1986-01-01

The experiments involved quantitative comparative mutagenesis determinations using ethylating agents differing in DNA reactivity, mammalian metabolism, and mutagenic potency. The results can be summarized as follows: (1) Under standardized in vitro treatment conditions and at identical DNA dose levels, the frequencies of induced mutations observed in the present bacterial systems are not representative and usually lower than those induced in cultured mammalian cells. (2) Under the same in vitro treatment conditions, the relative mutagenic potency order is identical in bacteria and the mammalian cells, namely, N-ethyl-N'-nitrosoquinioline(ENNG) > ethylnitrosourea (ENU) > diethylsulfate (DES) > ethylmethanesulfonate (EMS); diethylnitrosamine (DEN) being not mutagenic in the two organisms without addition of mammalian (rodent) liver preparations containing Cyt-P450-dependent mixed function oxidases. (3) The extremely high mutagenic activity of ENNG in bacteria and mammalian cells in vitro is very probably due to its intracellular, glutathione-mediated activation to highly reactive chemical species. (4) Both in bacteria and the mammalian cells the frequencies of induced mutations are directly proportional to the levels of O6-ethylguanine formed in DNA after exposure to ENNG, ENU, DES, and EMS, in contrast to results obtained when other DNA adducts are used as dose parameters. (5) The addition of mouse liver S-9 preparations in the in vitro assays allows to determine which chemicals are likely to be substantially activated (DEN) or deactivated (ENNG) in vivo; however, the mutagenic potency order remained the same under these conditions. (6) When the indicator bacteria are exposed directly to the in vivo metabolism of living animals, the relative order of mutagenic potency on the basis of exposure levels becomes drastically different from that observed in vitro, using either E. coli or V79 mammalian cells.

Surface Modification of Polypropylene Microporous Membrane by Atmospheric-Pressure Plasma Immobilization of N,N-dimethylamino Ethyl Methacrylate

International Nuclear Information System (INIS)

Zhong Shaofeng

2010-01-01

Surface modification of polypropylene microporous membrane (PPMM) was performed by atmospheric pressure dielectric barrier discharge plasma immobilization of N,N-dimethylamino ethyl methacrylate (DMAEMA). Structural and morphological changes on the membrane surface were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM). Water contact angles of the membrane surfaces were also measured by the sessile drop method. Results reveal that both the plasma-treating conditions and the adsorbed DMAEMA amount have remarkable effects on the immobilization degree of DMAEMA. Peroxide determination by 1,1-diphenyl-2-picrvlhydrazyl (DPPH) method verifies the exsistence of radicals induced by plasma, which activize the immobilization reaction. Pure water contact angle on the membrane surface decreased with the increase of DMAEMA immobilization degree, which indicates an enhanced hydrophilicity for the modified membranes. The effects of immobilization degrees on pure water fluxes were also measured. It is shown that pure water fluxes first increased with immobilization degree and then decreased. Finally, permeation of bovine serum albumin (BSA) and lysozyme solution were measured to evaluate the antifouling property of the DMAEMA-modified membranes, from which it is shown that both hydrophilicity and electrostatic repulsion are beneficial for membrane antifouling.

Evaluation of the E mu-pim-1 transgenic mouse model for short-term carcinogenicity testing

DEFF Research Database (Denmark)

van Kreijl, C. F.; van Oordt, C. W. V.; Kroese, E. D.

1998-01-01

of T-cell lymphomas. Because of the low incidence of spontaneous tumors and the increased sensitivity to N-ethyl-N-nitrosourea-induced carcinogenesis, E mu-pim-1 mice were suggested to be one of the first potential and attractive candidates to be used in short-term carcinogenicity testing...

Crystal structure of chlorido(2-{1-[2-(4-chlorophenylhydrazin-1-ylidene-κN]ethyl}pyridine-κN(η5-pentamethylcyclopentadienylrhodium(III chloride

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Neelakandan Devika

2015-03-01

Full Text Available The cation of the title compound, [Rh(η5-C5Me5Cl(C13H12ClN3]Cl, adopts a typical piano-stool geometry. The complex is chiral at the metal and crystallizes as a racemate. Upon coordination, the hydrazinylidenepyridine ligand is non-planar, an angle of 54.42 (7° being observed between the pyridine ring and the aromatic ring of the [2-(4-chlorophenylhydrazin-1-ylidene]ethyl group. In the crystal, a weak interionic N—H...Cl hydrogen bond is observed.

CD48-deficient T-lymphocytes from DMBA-treated rats have de novo mutations in the endogenous Pig-a gene.

Science.gov (United States)

Dobrovolsky, Vasily N; Revollo, Javier; Pearce, Mason G; Pacheco-Martinez, M Monserrat; Lin, Haixia

2015-10-01

A major question concerning the scientific and regulatory acceptance of the rodent red blood cell-based Pig-a gene mutation assay is the extent to which mutants identified by their phenotype in the assay are caused by mutations in the Pig-a gene. In this study, we identified T-lymphocytes deficient for the glycosylphosphatidylinositol-anchored surface marker, CD48, in control and 7,12-dimethylbenz[a]anthracene (DMBA)-treated rats using a flow cytometric assay and determined the spectra of mutations in the endogenous Pig-a gene in these cells. CD48-deficient T-cells were seeded by sorting at one cell per well into 96-well plates, expanded into clones, and exons of their genomic Pig-a were sequenced. The majority (78%) of CD48-deficient T-cell clones from DMBA-treated rats had mutations in the Pig-a gene. The spectrum of DMBA-induced Pig-a mutations was dominated by mutations at A:T, with the mutated A being on the nontranscribed strand and A → T transversion being the most frequent change. The spectrum of Pig-a mutations in DMBA-treated rats was different from the spectrum of Pig-a mutations in N-ethyl-N-nitrosourea (ENU)-treated rats, but similar to the spectrum of DMBA mutations for another endogenous X-linked gene, Hprt. Only 15% of CD48-deficient mutants from control animals contained Pig-a mutations; T-cell biology may be responsible for a relatively large fraction of false Pig-a mutant lymphocytes in control animals. Among the verified mutants from control rats, the most common were frameshifts and deletions. The differences in the spectra of spontaneous, DMBA-, and ENU-induced Pig-a mutations suggest that the flow cytometric Pig-a assay detects de novo mutation in the endogenous Pig-a gene. © 2015 Wiley Periodicals, Inc.

Towards optimizing the sequence of bevacizumab and nitrosoureas in recurrent malignant glioma.

Science.gov (United States)

Wiestler, Benedikt; Radbruch, Alexander; Osswald, Matthias; Combs, Stephanie E; Jungk, Christine; Winkler, Frank; Bendszus, Martin; Unterberg, Andreas; Platten, Michael; Wick, Wolfgang; Wick, Antje

2014-03-01

Studies on the monoclonal VEGF-A antibody bevacizumab gave raise to questions regarding the lack of an overall survival benefit, the optimal timing in the disease course and potential combination and salvage therapies. We retrospectively assessed survival, radiological progression type on bevacizumab and efficacy of salvage therapies in 42 patients with recurrent malignant gliomas who received bevacizumab and nitrosourea sequentially. 15 patients received bevacizumab followed by nitrosourea at progression and 27 patients vice versa. Time to treatment failure, defined as time from initiation of one to failure of the other treatment, was similar in both groups (9.6 vs. 9.2 months, log rank p = 0.19). Progression-free survival on nitrosoureas was comparable in both groups, while progression-free survival on bevacizumab was longer in the group receiving bevacizumab first (5.3 vs. 4.1 months, log rank p = 0.03). Survival times were similar for patients with grade III (n = 9) and grade IV (n = 33) tumors. Progression-free survival on bevacizumab for patients developing contrast-enhancing T1 progression was longer than for patients who displayed a non-enhancing T2 progression. However, post-progression survival times after bevacizumab failure were not different. Earlier treatment with bevacizumab was not associated with better outcome in this series. The fact that earlier as compared to later bevacizumab treatment does not result in a different time to treatment failure highlights the challenge for first-line or recurrence trials with bevacizumab to demonstrate an overall survival benefit if crossover of bevacizumab-naïve patients after progression occurs.

Crystal structure of bis-[N-(2-hy-droxy-eth-yl)-N-methyl-dithio-carbamato-κ2S,S'](pyridine)-zinc(II) pyridine monosolvate and its N-ethyl analogue.

Science.gov (United States)

Poplaukhin, Pavel; Tiekink, Edward R T

2017-07-01

The common structural feature of the title compounds, [Zn(C 4 H 8 NOS 2 ) 2 (C 5 H 5 N)]·C 5 H 5 N (I) and [Zn(C 5 H 10 NOS 2 ) 2 (C 5 H 5 N)]·C 5 H 5 N (II), which differ by having di-thio-carbamate N-bound methyl (I) and ethyl (II) groups, is the coordination of each Zn II atom by two non-symmetrically chelating di-thio-carbamate ligands and by a pyridine ligand; in each case, the non-coordinating pyridine mol-ecule is connected to the Zn-containing mol-ecule via a (hy-droxy)O-H⋯N(pyridine) hydrogen bond. The resulting NS 4 coordination geometry is closer to a square-pyramid than a trigonal bipyramid in the case of (I), but almost inter-mediate between the two extremes in (II). The mol-ecular packing features (hy-droxy)O-H⋯O(hy-droxy) hydrogen bonds, leading to supra-molecular chains with a zigzag arrangement along [10-1] (I) or a helical arrangement along [010] (II). In (I), π-π [inter-centroid distances = 3.4738 (10) and 3.4848 (10) Å] between coordinating and non-coordinating pyridine mol-ecules lead to stacks comprising alternating rings along the a axis. In (II), weaker π-π contacts occur between centrosymmetrically related pairs of coordinating pyridine mol-ecules [inter-centroid separation = 3.9815 (14) Å]. Further inter-actions, including C-H⋯π(chelate) inter-actions in (I), lead to a three-dimensional architecture in each case.

Effects of liarozole fumarate (R85246) in combination with tamoxifen on N-methyl-N-nitrosourea (MNU)-induced mammary carcinoma and uterus in the rat model

International Nuclear Information System (INIS)

Goss, Paul E; Strasser-Weippl, Kathrin; Qi, Shangle; Hu, Haiqing

2007-01-01

Liarozole fumarate (liarozole – R85246) is a novel compound with characteristics of both aromatase inhibitor (AI) and a retinoic acid metabolism blocking agent (RAMBA). Our objective was to determine the effects of liarozole alone or in combination with tamoxifen on the N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinoma model, as well as on the uterus in ovariectomized immature rats. (1) Tumor burden experiments: Animals bearing one or more tumors greater than 10 mm in diameter were treated for 56 consecutive days with 20 mg/kg or 80 mg/kg of liarozole by oral gavage, tamoxifen 100 μg/kg by subcutaneous injection, or a combination of liarozole and tamoxifen. At the end of the treatment period, total cumulative tumor volume as well as retinoic acid levels were measured. (2) Uterotrophic assay and proliferation experiments: 21-day-old ovariectomized (OVX) Sprague-Dawley rats were treated with 20 mg/kg or 80 mg/kg of liarozole by oral gavage, tamoxifen 1 mg/kg by subcutaneous injection, and combination of both for 4 consecutive days. At the end of the treatment period, uterine weight, epithelial lining cell height and indices of proliferation cell nuclear antigen (PCNA) were measured. The tumor burden experiments in rats bearing estrogen receptor (ER) positive mammary tumours showed that liarozole has a marked anti-tumour effect. In combination with tamoxifen, liarozole had neither an additive nor an antagonistic effect. However, liarozole markedly reduced the uterotrophic effects induced by tamoxifen. Liarozole's antitumor effects on ER positive mammary tumors and its protective effect on the uterus merit further studies to confirm its clinical value in combination with tamoxifen in ER positive postmenopausal breast cancer. Liarozole and other retinomimetics might also be suitable chemoprevention drugs in combination with tamoxifen because of their favorable toxicity profile

Proceedings of the Annual Conference on Environmental Toxicology (5th) Held at Fairborn, OH on 24-26 September 1974

Science.gov (United States)

1974-12-01

naphthylamine, benzidine and derivatives, 4-biphenylamine, 4-nitrobiphenyl, auramine and magenta) Alkylating Agents (chlornaphthazlne, mustard gas...recently developed carborane-silicone columns (Willeboordse et al., 1968; Yancey and Lynn, 1974). Alkylating Agents Several alkylating agents have emerged...Magee, "Nitrosamine-Induced Carcinogenesis. The Alkylation of N-7 of Guanine of Nucleic Acids of the Rat by Diethylnitrosamine N-Ethyl-N- Nitrosourea

Study on selective separation of uranium(VI) by new N,N-dialkyl carboxy-amides

International Nuclear Information System (INIS)

Suzuki, Shinichi; Sugo, Yumi; Kimura, Takaumi; Yaita, Tsuyoshi

2007-01-01

-amides and group separation of Pu-Np linear alkyl type N,N-di-alkyl carboxy-amide for FBR and LWR spent fuel treatment. Since the branched alkyl type N,N-di-alkyl carboxy-amides have the steric hindrance on the complexation with metal cations, branched alkyl type N,N-di-alkyl carboxy-amides can be used to separate An(VI) from An(IV). On the other hand, linear type N,N-di-alkyl carboxy-amides have potential for alternative extractant for tri-butyl phosphate(TBP) because linear type N,N-di-alkyl-amide can extract An(VI) and An(IV). In our previous research work, we have proposed N,N-di-(2- ethyl)hexyl-(2,2-dimethyl)-propanamide (D2EHDMPA) as a candidate extractant for uranium selective separation in FBR spent fuel treatments. However D2EHDMPA was able to separate uranium(VI) from plutonium(IV) and neptunium(VI), D2EHDMPA showed poor U(VI) loading capacity in organic phase. For the purpose of improvement of U(VI) loading capacity in organic phase, nineteenth kinds of New N,N-di-alkyl-amides: N,N-di-hexyl-(3,3-dimethyl)butanamide (DHDMBA), N,N-di-oxyl-(3,3-dimethyl)butanamide (DODMBA), N,N-di-hexyl-(2,2-dimethyl)propanamide (DHDMPA) N,N-di-octyl-(2,2-dimethyl)propanamide (DODMPA), N,N-di-octyl-(2-ethyl)butanamide (DO2EBA), N,N-di-hexyl-(2-ethyl)butanamide (DH2EBA), N-benzyl-N-R 1 -(2-ethyl)hexanamide (R 1 :- C 4 H 9 , -C 6 H 13 , -C 8 H 17 , N-cyclohexyl-N-R 1 -(2- ethyl)hexanamide (R 1 :-C 4 H 9 , -C 6 H 13 , -C 8 H 17 ), N-phenyl- N-R 1 -(2-ethyl)hexanamide (R 1 :-C 3 H 9 , -C 4 H 9 , -C 5 H 11 , - C 6 H 13 , -C 8 H 17 , N-(2-ethyl)hexyl-N-Phenyl-octanamide, N-Benzyl- N-Phenyl-(2-ethyl)hexanamide are synthesized. In this paper, our experimental results of new N,N-dialkyl carboxy-amides extraction property of U(VI)/Pu(IV), extraction of macro amount of U(VI), and gamma-ray radiolysis will be summarized. Solvent extraction of U(VI) and Pu (IV) by nineteenth kinds of new N,N-di-alkyl carboxy-amides, macro amount of U(VI) extraction and radiolysis of four compounds were carried

Ultrasonic velocities, densities, and excess molar volumes of binary mixtures of N,N-dimethyl formamide with methyl acrylate, or ethyl acrylate, or butyl acrylate, or 2-ethyl hexyl acrylate at T = 308.15 K

Energy Technology Data Exchange (ETDEWEB)

Kondaiah, M. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522510, Andhra Pradesh (India); Sravana Kumar, D. [Dr. V.S. Krishna Govt. Degree College, Visakhapatnam, Andhra Pradesh (India); Sreekanth, K. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522510, Andhra Pradesh (India); Krishna Rao, D., E-mail: krdhanekula@yahoo.co.in [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522510, Andhra Pradesh (India)

2011-12-15

Highlights: > Positive values of V{sub m}{sup E}, indicate dispersion forces between acrylic esters and DMF. > V{sub m}{sup E} values compared with Redlich-Kister polynomial. > Partial molar volumes data conclude that weak interactions exist in the systems. > Measured velocity values compared with theoretical values obtained by polynomials. - Abstract: Ultrasonic velocities, u, densities, {rho}, of binary mixtures of N,N-dimethyl formamide (DMF) with methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), and 2-ethyl hexyl acrylate (EHA), including pure liquids, over the entire composition range have been measured at T = 308.15 K. Using the experimental results, the excess molar volume, V{sub m}{sup E}, partial molar volumes, V-bar {sub m,1}, V-bar{sub m,2}, and excess partial molar volumes, V-bar{sub m,1}{sup E}, V-bar{sub m,2}{sup E} have been calculated. Molecular interactions in the systems have been studied in the light of variation of excess values of calculated properties. The excess properties have been fitted to Redlich-Kister type polynomial and the corresponding standard deviations have been calculated. The positive values of V{sub m}{sup E} indicate the presence of dispersion forces between the DMF and acrylic ester molecules. Further theoretical values of sound velocity in the mixtures have been evaluated using various theories and have been compared with experimental sound velocities to verify the applicability of such theories to the systems studied. Theoretical ultrasonic velocity data have been used to study molecular interactions in the binary systems investigated.

Promoting effects of potassium dibasic phosphate on early-stage renal carcinogenesis in unilaterally nephrectomized rats treated with N-ethyl-N-hydroxyethylnitrosamine.

Science.gov (United States)

Hiasa, Y; Konishi, N; Nakaoka, S; Nakamura, T; Nishii, K; Ohshima, M

1992-07-01

The effects of potassium dibasic phosphate (PDP), potassium aluminum sulfate (PAS) and copper sulfate (CS) on early-stage renal carcinogenesis were investigated in unilaterally nephrectomized male Wistar rats after N-ethyl-N-hydroxyethylnitrosamine (EHEN) administration. After feeding 1,000 ppm EHEN, or basal diet for 2 weeks and removal of the left kidney at week 3, male Wistar rats were divided into 8 groups of 20 rats each. These groups received the following dietary treatments: 50,000 ppm PDP, 50,000 ppm PAS, 5,000 ppm CS or basal diet, respectively, for 18 weeks from weeks 3 to 20. The average numbers of adenomatous hyperplasias counted as preneoplastic lesions in the EHEN with 50,000 ppm PDP group were significantly higher than in the EHEN alone group or the EHEN followed by 50,000 ppm PAS or 5,000 ppm CS group. The treatment with 50,000 ppm PDP induced renal calcification and promoted the development of preneoplastic lesions in unilaterally nephrectomized rats treated with EHEN, but that with 50,000 ppm PAS or 5,000 ppm CS did not.

Poly(N,N -dibromo-N-ethyl-benzene-1,3-disulphonamide)

Indian Academy of Sciences (India)

catalysed oxidative coupling,12 a solid-phase synthe- sis,13 microwave ... The reaction was monitored by TLC (5:1, n-hexane/acetone). After completion of the reaction, CH2Cl2 (10 mL) was added and organic layer was separated and dried (MgSO4). Evaporation of ..... avoids the use of hazardous acids or bases. Also, we ...

The immobilized NaHSO4·H2O on activated charcoal: a highly efficient promoter system for N-formylation of amines with ethyl formate

Directory of Open Access Journals (Sweden)

Behzad Zeynizadeh

2016-03-01

Full Text Available The immobilized NaHSO4·H2O on activated charcoal was used as a highly efficient promoter system for facile N-formylation of amines with ethyl formate. All reactions were carried out in refluxing ethyl formate (54 ºC under mild conditions within 10-100 min to afford the product formamides in high to excellent yields (80-94%.

Crystal structure of N,N-diethylbenzene-1,4-diaminium dinitrate

Directory of Open Access Journals (Sweden)

Yasmina Bouaoud

2014-11-01

Full Text Available In the structure of the title molecular salt, C10H18N22+·2NO3−, the dinitrate salt of 4-(N,N-diethylaminoaniline, the two ethyl groups lie almost perpendicular to the plane of the benzene ring [the ring-to-ethyl C—C—N—C torsion angles are −59.5 (2 and 67.5 (3°]. The aminium groups of the cation form inter-species N—H...O hydrogen bonds with the nitro O-atom acceptors of both anions, giving rise to chain substructures lying along c. The chains are linked via further N—H...O hydrogen bonds, forming two-dimensional networks lying parallel to (010. These sheets are linked by C—H...O hydrogen bonds, forming a three-dimensional structure.

Synthesis, in vitro validation and in vivo pharmacokinetics of [{sup 125}I]N-[2-(4-iodophenyl)ethyl]-N-methyl-2-(1-piperidinyl) ethylamine: A high-affinity ligand for imaging sigma receptor positive tumors

Energy Technology Data Exchange (ETDEWEB)

John, Christy S; Gulden, Mary E; Vilner, Bertold J; Bowen, Wayne D

1996-08-01

N-[2-(4-iodophenyl)ethyl]-N-methyl-2-(1-piperidinyl)ethylamine, IPEMP, and the corresponding bromo derivative, BrPEMP, have been synthesized and characterized. Both BrPEMP and IPEMP were evaluated for sigma-1 and sigma-2 subtype receptor affinities and found to possess very high affinities for both receptor subtypes. The precursor for radioiodination n-tributylstannylphenylethylpiperidinylethylamine was prepared from its bromo derivative by palladium-catalyzed stannylation reaction. Radioiodinated 4-[{sup 125}I]PEMP was readily prepared in high yields and high specific activity by oxidative iododestannylation reaction using chloramine-T as oxidizing agent. Sites labeled by 4-[{sup 125}I]PEMP in guinea pig brain membranes showed high affinity for BD1008, haloperidol, and (+)-pentazocine (Ki = 5.06 {+-} 0.40, 32.6 {+-} 2.75, and 48.1 {+-} 8.60 nM, respectively), which is consistent with sigma receptor pharmacology. Competition binding studies of 4-[{sup 125}I]PEMP in melanoma (A375) and MCF-7 breast cancer cells showed a high affinity, dose-dependent inhibition of binding with known sigma ligand N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl) ethylamine, BD1008 (Ki = 5, 11 nM, respectively), supporting the labeling of sigma sites in these cells. Haloperidol, however showed a weaker (Ki 100-200 nM) affinity for the sites labeled by 4-[{sup 125}I]PEMP in these cells. Biodistribution studies of 4-[{sup 125}I]PEMP in rats showed a fast clearance of this radiopharmaceutical from blood, liver, lung, and other organs. A co-injection of 4-IPEMP with 4-[{sup 125}I]PEMP resulted in 37%, 69%, and 35% decrease in activity in liver, kidney, and brain (organs possessing sigma receptors), respectively at 1-h postinjection. These results suggest that 4-[{sup 125}I]PEMP is a promising radiopharmaceutical for pursuing further studies in animal models with tumors.

Comparison of new nitrosoureas esters with modified steroidal nucleus for cytogenetic and antineoplastic activity.

Science.gov (United States)

Hussein, A; Mioglou-Kalouptsi, E; Papageorgiou, A; Karapidaki, I; Iakovidou-Kritsi, Z; Lialiaris, T; Xrysogelou, E; Camoutsis, C; Mourelatos, D

2007-01-01

Nitrosourea is decomposed under physiological conditions to react with biological macromolecules by two mechanisms: alkylation (with proteins and nucleic acids) and carbamoylation (with proteins but not nucleic acids). It has been suggested that the alkylating action is responsible for the therapeutic effects of nitrosoureas, and that the carbamoylation activity leads to toxicity effects. In order to reduce systemic toxicity and improve specificity and distribution for cancer therapy, 2-haloethyl nitrosourea has been esterified with modified steroids, which are used as biological platforms for transporting the alkylating agent to the tumor site in a specific manner. The cytogenetic and antineoplastic effect were studied of seven newly synthesized esters of N,N-bis(2-chloroethyl)alanyl carboxyl derivatives with a modified steroidal nucleus (compounds 1-7). As a very sensitive indicator of genotoxicity the Sister Chromatid Exchange (SCE) assay was used and as a valuable marker of cytostatic activity the cell Proliferation Rate Index (PRI) in cultures of normal human lymphocytes was used. The order of magnitude of the cytogenetic activity on a molar basis (15, 30, 120 microM) of the compounds was 7>6>3>5>2>4>1. The most active compound 7 has an enlarged (seven carbon atoms) A ring modified with a lactam group (-NHCO-) with the nitrosourea moiety esterified at position 17 In the group of seven substances a correlation was observed between the magnitude of SCE response and the depression in PRI (r=-O, 65, p6>2>5>4>3>1 and on lympocytic P388 leukemia cells is 7>2>6>5>4>3>1. The present results are in agreement with previous suggestions that the effectiveness in cytogenetic activity may well be correlated with antitumor effects [T/C: 248% for the compound 7 in 250 mg/kg b.w.; T/C: mean survival time of drug-treated animals (T) (excluding long term survivals) vs. corn-oil-treated controls (C)].

The preparation and characterization of uns-cis-(ethylene-diamine-N,N'-di-3-propionato(N-alkylethylenediaminescobalt(III complexes

Directory of Open Access Journals (Sweden)

SANJA R. GRGURIC

2000-03-01

Full Text Available Three octahedral cobalt(III complexes of the general formula uns-cis-SCo(eddp(R-enCClÿ2H2O, where eddp = the tetradentate ONNO-type ligand ethylenediamine-N,N'-di-3-propionate and R-en = a bidentate NN-type ligand, either N-methyl, N-ethyl or N-isopropylethylenediamine. The complexes were prepared by the reaction of sodium uns-cis-(ethylenediamine-N,N'-di-3-propionato(carbonatocobaltate(IIIdihydrate with the corresponding diamine. They were isolated chromatographically and characterized by elemental analysis, infrared and electronic absorption spectroscopy.

Synthesis and properties of new cationic polymers on 2-[(methacryloyloxy)ethyl]trimethyl ammonium chloride and N-isopropylacrylamidet base

International Nuclear Information System (INIS)

Sergaziev, A.; Khutoryanskij, V.; Bajzhumanova, T.; Fefelova, N.; Nurkeeva, Z.

2003-01-01

New water-soluble cationic polyelectrolytes were synthesized by γ-radiation copolymerization of 2-[(methacryloyloxy)ethyl]trimethyl ammonium chloride and N-isopropylacrylamide. The phase transition of aqueous solutions of copolymers was studied with temperature increase in presence and absence of inorganic salts. The copolymers complexation with potassium hexacyano ferrates (II, III) was investigated. It was shown that the poly-complexes solubility depends on concentration of interacting reagents and temperature. (author)

Main metabolites of 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea and 1-(2-chloroethyl)-3-(2',3', 4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea in rats

International Nuclear Information System (INIS)

Madelmont, J.C.; Moreau, M.F.; Godeneche, D.; Duprat, J.; Plagne, R.; Meyniel, G.

1982-01-01

The metabolism of two glycosylnitrosoureas, 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea (RFCNU) and 1-(2-chloroethyl)-3-(2',3',4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea (RPCNU), has been investigated in the rat. With the label on the carboxyl moiety of RFCNU, we have shown that hydrolysis of the 4-nitrobenzoyl ester occurred to a large extent in vivo; 4-nitrobenzoic acid and its glucuronide were the major urinary metabolites. Two other minor metabolites and their glucuronides were identified as 4-aminobenzoic acid and 4-acetamidobenzoic acid. With the label on the chloroethyl moieties of RFCNU and RPCNU, we have shown that chloroethanol was a major degradation product of this alkylating part of the molecule. The concentration of chloroethanol in plasma vs. time has been determined. In urine, four metabolites derived from alkylated glutathione, namely thiodiacetic acid and its sulfoxide, N-acetylcarboxymethylcysteine, and N-acetylhydroxyethylcysteine, have been identified

Thermochemical properties of 4-N,N-dialkylamino-7-nitrobenzofurazan derivatives (alkyl = methyl, ethyl)

International Nuclear Information System (INIS)

Santos, Ana Filipa L.O.M.; Silva, Ana L.R.; Santiago, Otília D.F.; Gonçalves, Jorge M.; Pandey, Siddharth; Acree, W.E.; Ribeiro da Silva, Maria D.M.C.

2014-01-01

Highlights: • Combustion of 4-N,N-dialkylamino-7-nitrobenzofurazan by static bomb calorimetry. • Enthalpies of sublimation of 4-N,N-dialkylamino-7-nitrobenzofurazan. • Gaseous enthalpies of formation of 4-N,N-dialkylamino-7-nitrobenzofurazan. • Comparison between experimental and calculated (G3(MP2)//B3LYP approach) enthalpies of formation, in the gaseous phase. - Abstract: The standard (p° = 0.1 MPa) molar enthalpies of formation, at T = 298.15 K, in the gaseous phase, for two nitrobenzofurazan derivatives, 4-N,N-dimethylamino-7-nitrobenzofurazan (DMANBF) and 4-N,N-diethylamino-7-nitrobenzofurazan (DEANBF), were derived from their enthalpies of combustion and sublimation, obtained by static bomb calorimetry and by the Knudsen effusion technique, respectively. The results are compared with the corresponding data calculated by the G3(MP2)//B3LYP approach. Computationally, the molecular structures of both compounds were established and the geometrical parameters were determined at the B3LYP/6-31G(d) level of theory

Synthesis and biological evaluation of radioiodinated N-2-(4-piperidyl)ethyl benzamides

International Nuclear Information System (INIS)

Efange, S.M.N.; Michelson, R.H.; Boudreau, R.J.; Thomas, J.R.; Knusel, B.; Hefti, F.; Tennison, J.R.

1993-01-01

Three iodinated benzamides, 5-7, analogues of the potent acetylcholinesterase inhibitor 1-benzyl-4-[N-[4'-(benzylsulfonyl) benzoyl-N-methylamino]ethyl]piperidine (2), were synthesized and evaluated as potential anticholinesterase agents. All three compounds were found to be three orders of magnitude less potent than the parent compound. However, receptor screening revealed that compounds 5-7 exhibit nanomolar affinity for the sigma binding site. Both [ 125 I]5 and [ 125 I]7 were synthesized and evaluated in rats. Following the intravenous administration of [ 125 I]5 into rats, 1.59% of the injected dose was found in the rat brain within 5 min. The level of radioactivity in the brain remained steady for 2 h, the duration of the study. In contrast, 0.42% of the injected dose was detected in the rat brain following the i.v. injection of [ 125 I]7. Coadministration of either [ 125 I]5 or [ 125 I]7 with 0.5 μmol/kg of haloperidol resulted in a 56-73% reduction in the level of radioactivity in the rat brain, suggesting that these compounds bind to the sigma binding site in vivo. Planar imaging studies with [ 123 I]5 revealed significant accumulation of radioactivity within the monkey brain, with a half-life of 6 h. Compound [ 123 I]5 may be potentially useful for studying sigma receptor distribution in the human brain. (author)

Synthesis and biological evaluation of radioiodinated N-2-(4-piperidyl)ethyl benzamides

International Nuclear Information System (INIS)

Efange, S.M.N.; Michelson, R.H.; Boudreau, R.J.; Thomas, J.R.; Knusel, B.; Hefti, F.; Tennison, J.R.

1993-01-01

Three iodinated benzamides, 5-7, analogues of the potent acetylcholinesterase inhibitor 1-benzyl-4[N-[4'-(benzylsulfonyl) benzoyl-N-methylamino]ethyl]piperidine were synthesized and evaluated as potential anticholinesterase agents. All three compounds were found to be three orders of magnitude less potent than the parent compound. However, receptor screening revealed that compounds 5-7 exhibit nanomolar affinity for the sigma binding site. Both [ 125 I]5 and [ 125 I]7 were synthesized and evaluated in rats. Following the intravenous administration of [ 125 I]5 into rats, 1.59% of the injected dose was found in the rat brain within 5 min. The level of radioactivity in the brain remained steady for 2 h, the duration of the study. In contrast, 0.42% of the injected dose was detected in the rat brain following the i.v. injection of [ 125 I]7. Coadministration of either [ 125 I]5 or [ 125 I]7 with 0.5 μmol/kg of haloperidol resulted in a 56-73% reduction in the level of radioactivity in the rat brain, suggesting that these compounds bind to the sigma binding site in vivo. Planar imaging studies with [ 123 I]5 revealed significant accumulation of radioactivity within the monkey brain, with a half-life of 6 h. Compound [ 123 I]5 may be potentially useful for studying sigma receptor distribution in the human brain. (Author)

Improving isopropanol tolerance and production of Clostridium beijerinckii DSM 6423 by random mutagenesis and genome shuffling.

Science.gov (United States)

Gérando, H Máté de; Fayolle-Guichard, F; Rudant, L; Millah, S K; Monot, F; Ferreira, Nicolas Lopes; López-Contreras, A M

2016-06-01

Random mutagenesis and genome shuffling was applied to improve solvent tolerance and isopropanol/butanol/ethanol (IBE) production in the strictly anaerobic bacteria Clostridium beijerinckii DSM 6423. Following chemical mutagenesis with N-methyl-N-nitro-N-nitrosoguanidine (NTG), screening of putatively improved strains was done by submitting the mutants to toxic levels of inhibitory chemicals or by screening for their tolerance to isopropanol (>35 g/L). Suicide substrates, such as ethyl or methyl bromobutyrate or alcohol dehydrogenase inhibitors like allyl alcohol, were tested and, finally, 36 mutants were isolated. The fermentation profiles of these NTG mutant strains were characterized, and the best performing mutants were used for consecutive rounds of genome shuffling. Screening of strains with further enhancement in isopropanol tolerance at each recursive shuffling step was then used to spot additionally improved strains. Three highly tolerant strains were finally isolated and able to withstand up to 50 g/L isopropanol on plates. Even if increased tolerance to the desired end product was not always accompanied by higher production capabilities, some shuffled strains showed increased solvent titers compared to the parental strains and the original C. beijerinckii DSM 6423. This study confirms the efficiency of genome shuffling to generate improved strains toward a desired phenotype such as alcohol tolerance. This tool also offers the possibility of obtaining improved strains of Clostridium species for which targeted genetic engineering approaches have not been described yet.

Alkylation Induced DNA Repair and Mutagenesis in Escherichia coli.

Science.gov (United States)

1987-11-23

unrepaired 3-methyladenine in DNA 29 2.4.1 Cytotoxic effects of persisting m3A in DNA 30 2.4.2 Mutagenic bypass synthesis of depurinat ,d DNA 30 3 CONCLUDING...induced by a single exposure to the ca’rcinogen N- methyl-N- nitrosourea (MNU) due to activation of the malignant Ha-ras-i locus. Analysis of the induced...ing CO:A uolymerase I for repair synthesis . Since DNA polymerase I would be required to complete repair after the in~uial activity of TagII, we tested

n-3 PUFA Esterified to Glycerol or as Ethyl Esters Reduce Non-Fasting Plasma Triacylglycerol in Subjects with Hypertriglyceridemia

DEFF Research Database (Denmark)

Hedengran, Anne; Szecsi, Pal B; Dyerberg, Jørn

2015-01-01

To date, treatment of hypertriglyceridemia with long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) has been investigated solely in fasting and postprandial subjects. However, non-fasting triacylglycerols are more strongly associated with risk of cardiovascular disease. The objective of this st......To date, treatment of hypertriglyceridemia with long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) has been investigated solely in fasting and postprandial subjects. However, non-fasting triacylglycerols are more strongly associated with risk of cardiovascular disease. The objective...... of this study was to investigate the effect of long-chain n-3 PUFA on non-fasting triacylglycerol levels and to compare the effects of n-3 PUFA formulated as acylglycerol (AG-PUFA) or ethyl esters (EE-PUFA). The study was a double-blinded randomized placebo-controlled interventional trial, and included 120...... subjects with non-fasting plasma triacylglycerol levels of 1.7-5.65 mmol/L (150-500 mg/dL). The participants received approximately 3 g/day of AG-PUFA, EE-PUFA, or placebo for a period of eight weeks. The levels of non-fasting plasma triacylglycerols decreased 28 % in the AG-PUFA group and 22 % in the EE...

[Cancer chemotherapy with special reference to pharmacokinetics of nitrosoureas].

Science.gov (United States)

Wakui, A

1982-08-01

This paper provides an overview of cancer chemotherapy with special reference to the pharmacokinetics of the nitrosoureas. At physiological PH, the chloroethylnitrosoureas can be decomposed into an isocyanate and 2-chloroethyl diazene hydroxide. Therefore, it is clear that they have both alkylation and carbamoylation actions. In addition to the spontaneous chemical dissociation, the nitrosoureas can be metabolized by liver microsomal enzymes to more polar hydroxylated products, and certain nitrosoureas can be denitrosated by these enzymes to the parent urea. Since the lipid-soluble nitrosoureas and some of the water-soluble nitrosoureas such as ACNU and MCNU demonstrated to cross the blood-brain barrier, they have been used in the treatment of primary brain tumors and tumors and tumors of metastatic origin. It has been demonstrated from the results of our study and other reports that the alkylation of DNA by ACNU progresses more slowly as compared with that of other alkylating agents. This is an important finding in relation to the appearance of delayed myelosuppression of the nitrosoureas and in the design of dose schedules of these agents. The major clinical emphasis has been directed towards the more active chloroethylnitrosoureas with reduced myelosuppression, and attempts are now made for this purpose. Unfortunately, the results of phase I and II trials of the newly developed nitrosoureas suggest that these agents produce delayed and cumulative bone marrow toxicity. Antitumor activity of the nitrosoureas is frequestly observed in chronic myelocytic leukemia, malignant lymphoma, brain tumors and small cell carcinoma of the lung, and less frequently in gastrointestinal carcinoma, multiple myeloma and malignant melanoma. In order to enhance clinical effects of the nitrosoureas, further investigation of the design in therapeutic schedules on the basis of their pharmacokinetic characteristics will be needed.

[Chemotherapeutic characterization of new nitrosourea compounds].

Science.gov (United States)

Zeller, W J; Berger, M R; Eisenbrand, G; Petru, E

1988-01-01

The development of new nitrosoureas is described using selected examples. Results obtained with water-soluble analogs and with compounds linked to biomolecules as for instance amino acids, oligopeptides and steroids, are presented. The pronounced antineoplastic effect of some water-soluble analogs is paralleled by an increased rate of DNA-interstrand cross-links and by an increased suppression of hematopoietic stem cells. The suppression of bone marrow stem cells is followed by their rapid regeneration. Water-soluble nitrosoureas induce significant less inhibition of glutathione reductase as compared with established compounds. With regard to long-term toxicity and carcinogenicity water-soluble are superior to established compounds as for instance BCNU. Linking of the nitrosourea moiety to amino acids and oligopeptides led to some analogs with outstanding therapeutic ratio. Out of a group of steroid-linked nitrosoureas, CNC-L-alanine-estradiol-17-ester (CNC-ala-17-E2) is chosen to demonstrate the possibility of reducing bone marrow toxicity despite unchanged or increased therapeutic activity by attachment of the nitrosourea moiety to a steroid. Results of a comparative interspecies in vitro evaluation of CNC-ala-17-E2 in transplanted MXT mammary carcinoma of the mouse, MNU-induced autochthonous rat mammary carcinoma and primary human mammary carcinomas are presented and the question is discussed to what extent in vitro activity of such receptor agents using the tumor stem cell assay reflects their in vivo activity.

Photochemically activated antiviral halogenated 1,8-naphthalimides: synthesis of N,N'-bis-{2-[(5-bromo-2-[1-14C]hexyl-1H-benz[de]isoquinolin-1,3(2H)-dion-6-yl)amino]ethyl}hexanediamide

International Nuclear Information System (INIS)

Hayes, B.A.; Gupta, Surendra; Shaochieh Chang; Utecht, R.E.; Lewis, D.E.

1996-01-01

The synthesis of N,N'-bis-{2-[(5-bromo-2-[1- 14 C]hexyl-1H-benz[de]isoquinolin-1, 3(2H)-dion-6-yl)amino]ethyl}hexanediamide from 1-[1- 14 C]-hexylamine and 4-chloro-1,8-naphthalic anhydride is described. The anhydride is first converted to the 4-chloro-n-[1- 14 C]hexyl-1,8-naphthalimide by condensation with 1-[1- 14 C]-hexylamine, and the chlorine is then displaced with ethylenediamine to give the 4-(2-aminoethylamino-N-[1- 14 C]hexyl-1,8-naphthalimide. Coupling of this monomeric naphthalimide with adipoyl chloride affords the dimeric naphthalimide which is brominated regiospecifically with elemental bromine in carbon tetrachloride to afford the title compound. (author)

Synthesis and biological evaluation of radioiodinated N-2-(4-piperidyl)ethyl benzamides

Energy Technology Data Exchange (ETDEWEB)

Efange, S M.N.; Michelson, R H; Boudreau, R J; Thomas, J R [Minnesota Univ., Minneapolis, MN (United States); Knusel, B; Hefti, F [Minnesota Univ., Minneapolis, MN (United States). Hospitals; Tennison, J R [University of Southern Cailfornia, Los Angeles, CA (United States). Andrus Gerontology Center

1993-05-01

Three iodinated benzamides, 5-7, analogues of the potent acetylcholinesterase inhibitor 1-benzyl-4-[N-[4'-(benzylsulfonyl) benzoyl-N-methylamino]ethyl]piperidine (2), were synthesized and evaluated as potential anticholinesterase agents. All three compounds were found to be three orders of magnitude less potent than the parent compound. However, receptor screening revealed that compounds 5-7 exhibit nanomolar affinity for the sigma binding site. Both [[sup 125]I]5 and [[sup 125]I]7 were synthesized and evaluated in rats. Following the intravenous administration of [[sup 125]I]5 into rats, 1.59% of the injected dose was found in the rat brain within 5 min. The level of radioactivity in the brain remained steady for 2 h, the duration of the study. In contrast, 0.42% of the injected dose was detected in the rat brain following the i.v. injection of [[sup 125]I]7. Coadministration of either [[sup 125]I]5 or [[sup 125]I]7 with 0.5 [mu]mol/kg of haloperidol resulted in a 56-73% reduction in the level of radioactivity in the rat brain, suggesting that these compounds bind to the sigma binding site in vivo. Planar imaging studies with [[sup 123]I]5 revealed significant accumulation of radioactivity within the monkey brain, with a half-life of 6 h. Compound [[sup 123]I]5 may be potentially useful for studying sigma receptor distribution in the human brain. (author).

Synthesis and biological evaluation of radioiodinated N-2-(4-piperidyl)ethyl benzamides

Energy Technology Data Exchange (ETDEWEB)

Efange, S.M.N.; Michelson, R.H.; Boudreau, R.J.; Thomas, J.R. (Minnesota Univ., Minneapolis, MN (United States)); Knusel, B.; Hefti, F. (Minnesota Univ., Minneapolis, MN (United States). Hospitals); Tennison, J.R. (University of Southern Cailfornia, Los Angeles, CA (United States). Andrus Gerontology Center)

1993-05-01

Three iodinated benzamides, 5-7, analogues of the potent acetylcholinesterase inhibitor 1-benzyl-4-[N-[4'-(benzylsulfonyl) benzoyl-N-methylamino]ethyl]piperidine (2), were synthesized and evaluated as potential anticholinesterase agents. All three compounds were found to be three orders of magnitude less potent than the parent compound. However, receptor screening revealed that compounds 5-7 exhibit nanomolar affinity for the sigma binding site. Both [[sup 125]I]5 and [[sup 125]I]7 were synthesized and evaluated in rats. Following the intravenous administration of [[sup 125]I]5 into rats, 1.59% of the injected dose was found in the rat brain within 5 min. The level of radioactivity in the brain remained steady for 2 h, the duration of the study. In contrast, 0.42% of the injected dose was detected in the rat brain following the i.v. injection of [[sup 125]I]7. Coadministration of either [[sup 125]I]5 or [[sup 125]I]7 with 0.5 [mu]mol/kg of haloperidol resulted in a 56-73% reduction in the level of radioactivity in the rat brain, suggesting that these compounds bind to the sigma binding site in vivo. Planar imaging studies with [[sup 123]I]5 revealed significant accumulation of radioactivity within the monkey brain, with a half-life of 6 h. Compound [[sup 123]I]5 may be potentially useful for studying sigma receptor distribution in the human brain. (author).

DFT investigations of phosphotriesters hydrolysis in aqueous solution: a model for DNA single strand scission induced by N-nitrosoureas.

Science.gov (United States)

Liu, Tingting; Zhao, Lijiao; Zhong, Rugang

2013-02-01

DNA phosphotriester adducts are common alkylation products of DNA phosphodiester moiety induced by N-nitrosoureas. The 2-hydroxyethyl phosphotriester was reported to hydrolyze more rapidly than other alkyl phosphotriesters both in neutral and in alkaline conditions, which can cause DNA single strand scission. In this work, DFT calculations have been employed to map out the four lowest activation free-energy profiles for neutral and alkaline hydrolysis of triethyl phosphate (TEP) and diethyl 2-hydroxyethyl phosphate (DEHEP). All the hydrolysis pathways were illuminated to be stepwise involving an acyclic or cyclic phosphorane intermediate for TEP or DEHEP, respectively. The rate-limiting step for all the hydrolysis reactions was found to be the formation of phosphorane intermediate, with the exception of DEHEP hydrolysis in alkaline conditions that the decomposition process turned out to be the rate-limiting step, owing to the extraordinary low formation barrier of cyclic phosphorane intermediate catalyzed by hydroxide. The rate-limiting barriers obtained for the four reactions are all consistent with the available experimental information concerning the corresponding hydrolysis reactions of phosphotriesters. Our calculations performed on the phosphate triesters hydrolysis predict that the lower formation barriers of cyclic phosphorane intermediates compared to its acyclic counter-part should be the dominant factor governing the hydrolysis rate enhancement of DEHEP relative to TEP both in neutral and in alkaline conditions.

Reaction of N-(Per-O-acetyl-β-D-glucopyranosyl-Nʼ-(4ʼ,6ʼ-diarylpyrimidine-2ʼ-ylthioureas with Ethyl Bromoacetate

Directory of Open Access Journals (Sweden)

Nguyen Dinh Thanh

2011-01-01

Full Text Available Some new 2-iminothiazolidin-4-ones having pyrimidine ring have been synthesized by reaction of substituted N-(per-O-acetyl-β-D-glucopyranosyl-Nʼ-(4ʼ,6ʼ-diarylpyrimidine-2ʼ-ylthioureas with ethyl bromoacetate. The structure of isomeric products has been confirmed by spectroscopic methods, such as IR, 1H and 13C NMR.

A cerium(III) selective polyvinyl chloride membrane sensor based on a Schiff base complex of N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine

International Nuclear Information System (INIS)

Gupta, Vinod Kumar; Singh, A.K.; Gupta, Barkha

2006-01-01

A polyvinyl chloride (PVC) based membrane sensor for cerium ions was prepared by employing N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine as an ionophore, oleic acid (OA) as anion excluder and o-nitrophenyloctyl ether (o-NPOE) as plasticizer. The plasticized membrane sensor exhibits a Nernstian response for Ce(III) ions over a wide concentration range (1.41 x 10 -7 to 1.0 x 10 -2 M) with a limit of detection as low as 8.91 x 10 -8 M. It has a fast response time (<10 s) and can be used for 4 months. The sensor revealed a very good selectivity with respect to common alkali, alkaline earth and heavy metal ions. The response of the proposed sensor is independent of pH between 3.0 and 8.0. It was used as an indicator electrode in potentiometric titration of fluoride, carbonate and oxalate anions and determination of cerium in simulated mixtures

Effect of mutagen combined action on Chlamydomonas reinhardtii cells. I. Lethal effect dependence on the sequence of mutagen application and on cultivation conditions

Energy Technology Data Exchange (ETDEWEB)

Vlcek, D; Podstavkova, S; Dubovsky, J [Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta

1978-01-01

The effect was investigated of single and combined actions of alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) and UV-radiation on the survival of cells of Chlamydomonas reinhardtii algae in dependence on the sequence of application of mutagens and on the given conditions of cultivation following mutagen activity. In particular, the single phases were investigated of the total lethal effect, i.e., the death of cells before division and their death after division. The most pronounced changes in dependence on the sequence of application of mutagens and on the given conditions of cultivation were noted in cell death before division. In dependence on the sequence of application of mutagens, the effect of the combined action on the survival of cells changed from an additive (alkylnitrosourea + UV-radiation) to a protective effect (UV-radiation + alkylnitrosourea).

Effect of mutagen combined action on Chlamydomonas Reinhardtii cells. I

International Nuclear Information System (INIS)

Vlcek, D.; Podstavkova, S.; Dubovsky, J.

1978-01-01

The effect was investigated of single and combined actions of alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) and UV-radiation on the survival of cells of Chlamydomonas reinhardtii algae in dependence on the sequence of application of mutagens and on the given conditions of cultivation following mutagen activity. In particular, the single phases were investigated of the total lethal effect, i.e., the death of cells before division and their death after division. The most pronounced changes in dependence on the sequence of application of mutagens and on the given conditions of cultivation were noted in cell death before division. In dependence on the sequence of application of mutagens, the effect of the combined action on the survival of cells changed from an additive (alkylnitrosourea + UV-radiation) to a protective effect (UV-radiation + alkylnitrosourea). (author)

Commentary on "tissue-specific mutagenesis by N-butyl-N-(4-hydroxybutyl) nitrosamine as the basis for urothelial cell carcinogenesis." He Z, Kosinska W, Zhao ZL, Wu XR, Guttenplan JB, Department of Basic Science, New York University Dental College, NY, USA.: Mutat Res 2012;742(1-2):92-5 [Epub 2011 Dec 4].

Science.gov (United States)

Scherr, Douglas S

2014-02-01

Bladder cancer is one of the few cancers that have been linked to carcinogens in the environment and tobacco smoke. Of the carcinogens tested in mouse chemical carcinogenesis models, N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) is one that reproducibly causes high-grade, invasive cancers in the urinary bladder, but not in any other tissues. However, the basis for such a high-level tissue-specificity has not been explored. Using mutagenesis in lacI (Big Blue™) mice, we show here that BBN is a potent mutagen and it causes high-level of mutagenesis specifically in the epithelial cells (urothelial) of the urinary bladder. After a 2-6-week treatment of 0.05% BBN in the drinking water, mutagenesis in urothelial cells of male and female mice was about two orders of magnitude greater than the spontaneous mutation background. In contrast, mutagenesis in smooth muscle cells of the urinary bladder was about five times lower than in urothelial tissue. No appreciable increase in mutagenesis was observed in kidney, ureter, liver or forestomach. In lacI (Big Blue™) rats, BBN mutagenesis was also elevated in urothelial cells, albeit not nearly as profoundly as in mice. This provides a potential explanation as to why rats are less prone than mice to the formation of aggressive form of bladder cancer induced by BBN. Our results suggest that the propensity to BBN-triggered mutagenesis of urothelial cells underlies its heightened susceptibility to this carcinogen and that mutagenesis induced by BBN represents a novel model for initiation of bladder carcinogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

Molecular dosimetry of the chemical mutagen ethyl methanesulfonate

International Nuclear Information System (INIS)

Zeeland, A.A. van; Aaron, C.S.; Mohn, G.R.; Hung, C.Y.; Brockman, H.E.

1983-01-01

Extending previous work with E. coli and mammalian cells in culture, forward-mutation frequencies induced by ethyl methanesulfonate (EMS) were quantitatively compared in Neurospora crassa and Saccharomyces cerevisiae under standardized conditions. Concomitantly, the actual dose to DNA was measured by determining the amount of radioactivity bound to DNA after treatment with tritium-labeled EMS. After exposure to EMS (2.5-50 mM), alkylation levels in N. crassa and S. cerevisiae were similar to those previously determined in E. coli and cultured mammalian cells. Consistently, there was a slightly less than proportional increase of the DNA alkylation level with the exposure concentration of the mutagen. Forward mutagenesis induced in yeast and N. crassa showed exponential kinetics with exponents of 1.5 and 2.6, respectively. These results are similar to those previously reported with E. coli, which differed from the results with cultured mammalian cells, where a linear dose-effect relationship between exposure and genetic effect was observed. These differences may reflect differences in the fate of EMS-induced adducts by cellular DNA repair systems, but are not due to initial differences in DNA alkylation levels. The fate and persistence of specific DNA adducts potentially responsible for pre-mutagenic changes are under investigation. (orig.)

Specific enkephalin-degrading aminopeptidase activity in the HPT and HPO axes of rats with breast cancer induced by N-methyl nitrosourea.

Science.gov (United States)

Carrera, María del Pilar; Ramírez-Expósito, María Jesús; Valenzuela, María Teresa; García, María Jesús; Mayas, María Dolores; Arias de Saavedra, José Manuel; Sánchez, Rafael; Pérez, María del Carmen; Martínez-Martos, José Manuel

2005-01-15

State and function of breast depend on an endocrinological balance, the upsetting of which can be a factor favorable to the development of cancer. Enkephalins (ENK) have been considered as a particular form of adaptation to defense to the organism against neoplastic processes. However, ENK may modify the endocrine functions of glands such as the ovary or the thyroid through the hypothalamus-pituitary axis, acting direct or indirectly as endocrine, paracrine or autocrine stimulatory growth factors. The present work analyses enkephalin-degrading tyrosyl aminopeptidase (EDA) activity in the hypothalamus-pituitary-thyroid (HPT) and hypothalamus-pituitary-ovary (HPO) axes in a rat model of breast cancer induced by N-methyl-nitrosourea (NMU) to state the relationship between ENK levels modification through EDA activity at different neuroendocrine levels and breast cancer. Results obtained show a decrease in EDA activity in hypothalamus, anterior and posterior pituitary, thyroid and ovary, suggesting increased levels of ENK in all these locations. These ENK may induce breast cancer cell growth and progression not only at breast level, but also acting at several neuroendocrine levels such as the HPT and HPO axes, inducing an unbalance of several other hormones, which could also facilitate the progression of cancer as an undesirable concomitant effect.

Rapidly Degradable Pyrotechnic System

Science.gov (United States)

2009-02-01

material system (structural polymer and degradation agent ) for producing a high strength, non-corroding, highly inert, environmentally safe, extended...polymer sites in the active enzyme center differs dramatically between alkyl and aromatic polyesters. More specifically, as the degree of backbone...capped and centrifuged at 3,000 g. This procedure was repeated twice. To the remaining biomass pellet 15 mL of 1 mg/mL solution of N-ethyl-N- nitrosourea

SYNTHESIS OF N- ACETONITRIL AND N- ETHYLAMINE- 3- HYDROXYPYRIDINONES AS IRON (III CHELATORS

Directory of Open Access Journals (Sweden)

L.A. SAGHAEI

2000-12-01

Full Text Available Background. The need of iron-chelating agents as orally active alternatives to desferal for the treatment of iron overload in thalassaemic patients, has stimulated considerable research efforts in the synthesis of new metal chelators. One of the member of hydroxypyridinones (2,3- dimethyl-3- hydroxypyridinones has so far received the most attention. This compound is rapidly glucuronidated into a non-chelating metabolite, which partly explains why high doses of the compound has to be used in order to achieve negative balance. This metabolic behavior has led the medicinal chemists to design compounds such as N-hydroxyalkyl derivatives which do not undergo extensive metabolism. The objective of the present work was to further synthesis and design new derivatives of hydroxypyridinones (N- acetonitril and N-ethylamine derivatives Methods. The synthesis route involves the benzylation of hydroxyl group of maltol (ethyl maltol using benzyl chloride conversion of the benazylated maltol (ethyl maltol to the N-acetonitril bezylated pyridinone derivatives by introducing the aminoacetonitril in pyridine solvent and cleavage of benzyl group by hydrogenation method or using the bromodimethyl borane to form the N-acetonitril or N- ethylamine- 3- hydroxypyridinones respectively.
Results. In this work three final compounds such as 1- (2- aminoethyl- 2- methyl- 3-hydroxypyridin- 4- one, 1- (2- aminoethyl- 2- ethyl- 3- hydroxypyridin-4- one and 1- cyanomethyl -2- methyl- 3- hydroxypyridin- 4- one were synthesized.
Discussion. Identification and structural elucidation of compounds were achieved by IH NMR and Mass spectra, elemental analysis and through physical constants. The biological effects of compounds will be studied in the near future.

N-Cyclohexyl-N-ethylbenzenesulfonamide

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Islam Ullah Khan

2009-11-01

Full Text Available The title compound, C14H21NO2S, synthesized by N-methylation of cyclohexylamine sulfonamide with ethyl iodide is of interest as a precursor to biologically active sulfur-containing heterocyclic compounds. There are two independent molecules in the asymmetric unit. The dihedral angles between the mean planes of the phenyl ring and the cyclohexyl ring are 40.29 (11 and 37.91 (13° in the two molecules.

Influence of ethyl-trinexapac on 1{sup 5N} accumulation and distribution and on highland rice yield; Influencia do etil-trinexapac no acumulo, na distribuicao de nitrogenio ({sup 15}N) e na massa de graos de arroz de terras altas

Energy Technology Data Exchange (ETDEWEB)

Alvarez, Rita de Cassia Felix [Universidade Federal do Mato Grosso do Sul (UFMS), Chapadao do Sul, MS (Brazil)]. E-mail: ritaalvarez@nin.ufms.br; Crusciol, Carlos Alexandre Costa; Alvarez, Angela Cristina Camarim [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas. Depto. de Producao Vegetal]. E-mail: crusciol@fca.unesp.br; angela.alvarez@pop.com.br; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis]. E-mail: pcotrive@cena.usp.br; Rodrigues, Joao Domingos [UNESP, Botucatu, SP (Brazil). Inst. de Biociencias. Dept. de Botanica]. E-mail: mingo@unesp.br

2007-11-15

The high rice grain yields ensured by sprinkler irrigation have encouraged the use of higher fertilizer doses, mainly the nitrogen fertilizers. However, an improper management of nitrogen fertilization may result in plant lodging. Application of plant regulators may redirect assimilates to grain production while limiting the vegetative growth. This study aimed to: evaluate the influence of the growth regulator Ethyl-trinexapac on plant growth parameters and on {sup 15}N accumulation and distribution in the whole plant and plant components, and determine the contribution of nitrogen taken up in different developmental stages in panicle formation, yield components and rice yield. The experiment was carried out under controlled greenhouse conditions. The treatments consisted of application or not of a plant growth regulator (0 and 200 g active ingredient ha-1 of ethyl-trinexapac) at four plant development stages (beginning to end of tillering; end of tillering and flower differentiation; flower differentiation to flowering; flowering until physiological maturation). The experimental design was arranged in random blocks, in a 2 x 4 factorial scheme, with three replications. The plants were placed in a group of 48 pots. In a group of 24 pots with nutrient solution containing {sup 15}NH{sub 4}SO{sub 4}, plants were collected and separated in parts in the beginning of each pre-established plant development stage and at the end of each stage. In a second group (24 pots), pre-labeled plants were left to grow in nutrient solution with {sup 14}NH{sub 4}SO{sub 4} and harvested at the end of each cycle in order to access {sup 15}N redistribution.. The growth regulator reduced plant height and {sup 15}N accumulation in the panicle and promoted redistribution of the absorbed {sup 15}N, and increased accumulated {sup 15}N in root, stem+sheats and leaves. The contribution of absorbed {sup 15}N to panicle formation in each stage increased with the plant development, though in a

Chloroacetaldehyde-induced mutagenesis in Escherichia coli: The role of AlkB protein in repair of 3,N4-ethenocytosine and 3,N4-α-hydroxyethanocytosine

International Nuclear Information System (INIS)

Maciejewska, Agnieszka M.; Ruszel, Karol P.; Nieminuszczy, Jadwiga; Lewicka, Joanna; Sokolowska, Beata; Grzesiuk, Elzbieta; Kusmierek, Jaroslaw T.

2010-01-01

Etheno (ε) adducts are formed in reaction of DNA bases with various environmental carcinogens and endogenously created products of lipid peroxidation. Chloroacetaldehyde (CAA), a metabolite of carcinogen vinyl chloride, is routinely used to generate ε-adducts. We studied the role of AlkB, along with AlkA and Mug proteins, all engaged in repair of ε-adducts, in CAA-induced mutagenesis. The test system used involved pIF102 and pIF104 plasmids bearing the lactose operon of CC102 or CC104 origin (Cupples and Miller (1989) ) which allowed to monitor Lac + revertants, the latter arose by GC → AT or GC → TA substitutions, respectively, as a result of modification of guanine and cytosine. The plasmids were CAA-damaged in vitro and replicated in Escherichia coli of various genetic backgrounds. To modify the levels of AlkA and AlkB proteins, mutagenesis was studied in E. coli cells induced or not in adaptive response. Formation of εC proceeds via a relatively stable intermediate, 3,N 4 -α-hydroxyethanocytosine (HEC), which allowed to compare repair of both adducts. The results indicate that all three genes, alkA, alkB and mug, are engaged in alleviation of CAA-induced mutagenesis. The frequency of mutation was higher in AlkA-, AlkB- and Mug-deficient strains in comparison to alkA + , alkB + , and mug + controls. Considering the levels of CAA-induced Lac + revertants in strains harboring the pIF plasmids and induced or not in adaptive response, we conclude that AlkB protein is engaged in the repair of εC and HEC in vivo. Using the modified TTCTT 5-mers as substrates, we confirmed in vitro that AlkB protein repairs εC and HEC although far less efficiently than the reference adduct 3-methylcytosine. The pH optimum for repair of HEC and εC is significantly different from that for 3-methylcytosine. We propose that the protonated form of adduct interact in active site of AlkB protein.

Effect of mutagen combined action on Chlamydomonas reinhardtii cells. II. Dependence of lethal effect on mutagen dose and on conditions of cultivation following mutagen action. [In Slovak

Energy Technology Data Exchange (ETDEWEB)

Podstavkova, S; Vlcek, D; Dubovsky, J [Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta

1978-01-01

The effect of UV radiation and UV radiation combined with alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) was observed on survival of cells of the algae Chlamydomonas reinhardtii. In particular, single parts were evaluated of the overall lethal effect - dying of cells before division and dying of cells after division. It was found that the combined action of low doses of UV radiation and alkylnitrosoureas result in a pronounced protective effect which manifests itself by a higher frequency of surviving cells than was that effected by the action of alkylnitrosoureas alone. As a result of combined action with higher doses of UV radiation this effect is lost, and the resultant values will come close to the theoretically anticipated values. This gradual transition from a protective to an additive effect mainly manifests itself by changes in the proportion of cells dying before division.

Effect of mutagen combined action on Chlamydomonas reinhardtii cells. II

International Nuclear Information System (INIS)

Podstavkova, S.; Vlcek, D.; Dubovsky, J.

1978-01-01

The effect of UV radiation and UV radiation combined with alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) was observed on survival of cells of the algae Chlamydomonas reinhardtii. In particular, single parts were evaluated of the overall lethal effect - dying of cells before division and dying of cells after division. It was found that the combined action of low doses of UV radiation and alkylnitrosoureas result in a pronounced protective effect which manifests itself by a higher frequency of surviving cells than was that effected by the action of alkylnitrosoureas alone. As a result of combined action with higher doses of UV radiation this effect is lost, and the resultant values will come close to the theoretically anticipated values. This gradual transition from a protective to an additive effect mainly manifests itself by changes in the proportion of cells dying before division. (author)

Beneficial effects of spin-labelled nitrosourea on CCNU-induced oxidative stress in rat blood compared with vitamin E.

Science.gov (United States)

Gadjeva, V; Kuchukova, D; Tolekova, A; Tanchev, S

2005-07-01

This study was carried out to determine the effects of a recently synthesized 1-ethyl-3-[4-(2,2,6,6-tetra-methylpiperidine-1-oxyl)]-1-nitrosourea (SLENU), compared with vitamin E as a positive control, on 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU)-induced oxidative stress in rats. We determined plasma malonyl dialdehyde (MDA) levels and the activities of erythrocyte superoxide dismutase (SOD) and catalase (CAT). Forty two white albino healthy rats were treated once daily for 30 days with oral preparations of CCNU (12.5 mg/kg and 25 mg/kg), SLENU (25-200 mg/kg), and combinations of these. The CCNU-induced increase in plasma MDA level and the usual decrease in erythrocyte SOD and CAT activities were reversed by SLENU, but not by vitamin E. We have previously demonstrated that SLENU is a superoxide scavenger. A combination of our present findings with previous results thus leads us to proposing a new chemotherapeutic combination of CCNU and SLENU that is devoid of high toxicity.

The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent.

Science.gov (United States)

Nathan, Pradeep J; Lu, Kristy; Gray, M; Oliver, C

2006-01-01

L-theanine (N-ethyl-L-glutamine) or theanine is a major amino acid uniquely found in green tea. L-theanine has been historically reported as a relaxing agent, prompting scientific research on its pharmacology. Animal neurochemistry studies suggest that L-theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors. In addition has been shown to exert neuroprotective effects in animal models possibly through its antagonistic effects on group 1 metabotrophic glutamate receptors. Behavioural studies in animals suggest improvement in learning and memory. Overall, L-theanine displays a neuropharmacology suggestive of a possible neuroprotective and cognitive enhancing agent and warrants further investigation in animals and humans.

Mutagenesis in mammalian cells

International Nuclear Information System (INIS)

Burki, H.J.

1981-01-01

Mutagenic processes in synchronous cultures of Chinese hamster ovary cells have been studied. There is a difference in the induction of mutants by ultraviolet light during the cell cycle. There appears to be a sensitive period in the middle of the G1 stage of the cell cycle suggesting some mutagenic mechanism is present at that time. Studies indicate that mutation induction during the cell cycle is also mutagen specific since exposure to ethyl nitrosourea in the same system produces different results. Two clones have been isolated which are ultrasensitive to ultraviolet light. These cells are being used to determine if this hypermutability is cell-cycle dependent, related to cell cycle biochemistry, or to repair processes independent of cell cycle. Tritium and bromodeoxyuridine induced damage to synchronously dividing cell cultures are also being studied in relation to DNA replication. Cell killing by ionizing radiation is also related to the cell cycle. Sensitive times in the cell cycle for mutation induction by ionization radiation are identified

Treatment of mycosis fungoides with topical nitrosourea compounds: Further studies.

Science.gov (United States)

Zackheim, H S; Epstein, E H

1975-12-01

Twenty-six patients with mycosis fungoides were treated topically with three nitrosourea compounds: carmustine (BCNU), lomustine (CCNU), and 1-methyl-1-nitrosourea. A high percentage experienced good to excellent results. Remissions following treatment of individual lesions varied from one month to at least three years. Remissions following total body surface treatment varied from two weeks to at least four months. Two of 13 patients treated over the entire body suffered temporary bone marrow depression, indluding one with severe pancytopenia. This toxic effect was attributed to lomustine and was not seen in patients treated with carmustine alone. Thirteen patients highly allergic to mechlorethamine hydrochloride showed no cross-sensitivity to nitrosourea compounds. A primary irritant dermatitis occurred in about one half of the patients and telangiectasia in two. Two patients developed hypersensitivity to nitrosourea compounds. Carmustine is the preferred nitrosourea compound for topical therapy of mycosis fungoides.

LIQUID-CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC-ACIDS USING N-(4-AMINOBUTYL)-N-ETHYLISOLUMINOL AS CHEMILUMINESCENT LABEL - DETERMINATION OF IBUPROFEN IN SALIVA

NARCIS (Netherlands)

STEIJGER, OM; LINGEMAN, H; BRINKMAN, UAT; HOLTHUIS, JJM; SMILDE, AK; DOORNBOS, DA

1993-01-01

N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

Liquid chromatographic analysis of carboxylic acids using N-(4-aminobutyl)-N-ethylisoluminol as chemiluminescent label: determination of ibuprofen in saliva

NARCIS (Netherlands)

Steijger, O. M.; Lingeman, H.; Brinkman, U. A.; Holthuis, J. J.; Smilde, A. K.; Doornbos, D. A.

1993-01-01

N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

Noncompetitive inhibition of indolethylamine-N-methyltransferase by N,N-dimethyltryptamine and N,N-dimethylaminopropyltryptamine.

Science.gov (United States)

Chu, Uyen B; Vorperian, Sevahn K; Satyshur, Kenneth; Eickstaedt, Kelsey; Cozzi, Nicholas V; Mavlyutov, Timur; Hajipour, Abdol R; Ruoho, Arnold E

2014-05-13

Indolethylamine-N-methyltransferase (INMT) is a Class 1 transmethylation enzyme known for its production of N,N-dimethyltryptamine (DMT), a hallucinogen with affinity for various serotonergic, adrenergic, histaminergic, dopaminergic, and sigma-1 receptors. DMT is produced via the action of INMT on the endogenous substrates tryptamine and S-adenosyl-l-methionine (SAM). The biological, biochemical, and selective small molecule regulation of INMT enzyme activity remain largely unknown. Kinetic mechanisms for inhibition of rabbit lung INMT (rabINMT) by the product, DMT, and by a new novel tryptamine derivative were determined. After Michaelis-Menten and Lineweaver-Burk analyses had been applied to study inhibition, DMT was found to be a mixed competitive and noncompetitive inhibitor when measured against tryptamine. The novel tryptamine derivative, N-[2-(1H-indol-3-yl)ethyl]-N',N'-dimethylpropane-1,3-diamine (propyl dimethyl amino tryptamine or PDAT), was shown to inhibit rabINMT by a pure noncompetitive mechanism when measured against tryptamine with a Ki of 84 μM. No inhibition by PDAT was observed at 2 mM when it was tested against structurally similar Class 1 methyltransferases, such as human phenylethanolamine-N-methyltransferase (hPNMT) and human nicotinamide-N-methyltransferase (hNNMT), indicating selectivity for INMT. The demonstration of noncompetitive mechanisms for INMT inhibition implies the presence of an inhibitory allosteric site. In silico analyses using the computer modeling software Autodock and the rabINMT sequence threaded onto the human INMT (hINMT) structure (Protein Data Bank entry 2A14 ) identified an N-terminal helix-loop-helix non-active site binding region of the enzyme. The energies for binding of DMT and PDAT to this region of rabINMT, as determined by Autodock, were -6.34 and -7.58 kcal/mol, respectively. Assessment of the allosteric control of INMT may illuminate new biochemical pathway(s) underlying the biology of INMT.

Drug summary: nitrosoureas

International Nuclear Information System (INIS)

Moertel, C.G.

1979-01-01

The metabolism, toxicity, and radiosensitivity effects of the nitrosoureas (CCNU, BCNU, hydroxyurea) are summarized from presentations of laboratory findings given at the Conference on Combined Modalities (CONF-7811155--). Effects upon mice, rats, and patients are discussed with regard to doses, side effects, and interactions with radiotherapy

Effects of methylphenidate on attention in Wistar rats treated with the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4).

Science.gov (United States)

Hauser, Joachim; Reissmann, Andreas; Sontag, Thomas-A; Tucha, Oliver; Lange, Klaus W

2017-05-01

The aim of this study was to assess the effects of the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) on attention in rats as measured using the 5-choice-serial-reaction-time task (5CSRTT) and to investigate whether methylphenidate has effects on DSP4-treated rats. Methylphenidate is a noradrenaline and dopamine reuptake inhibitor and commonly used in the pharmacological treatment of individuals with attention deficit/hyperactivity disorder (ADHD). Wistar rats were trained in the 5CSRTT and treated with one of three doses of DSP4 or saline. Following the DSP4 treatment rats were injected with three doses of methylphenidate or saline and again tested in the 5CSRTT. The treatment with DSP4 caused a significant decline of performance in the number of correct responses and a decrease in response accuracy. A reduction in activity could also be observed. Whether or not the cognitive impairments are due to attention deficits or changes in explorative behaviour or activity remains to be investigated. The treatment with methylphenidate had no beneficial effect on the rats' performance regardless of the DSP4 treatment. In the group without DSP4 treatment, methylphenidate led to a reduction in response accuracy and bidirectional effects in regard to parameters related to attention. These findings support the role of noradrenaline in modulating attention and call for further investigations concerning the effects of methylphenidate on attentional processes in rats.

Phase equilibria and the thermodynamic properties of methyl and ethyl esters of carboxylic acids. 1. Methyl n-butanoate and ethyl propanoate

International Nuclear Information System (INIS)

Agafonova, Luba E.; Varushchenko, Raisa M.; Druzhinina, Anna I.; Polyakova, Olga V.

2012-01-01

Highlights: ► Heat capacities, fusion properties of CH 3 OC(O)C 3 H 7 measured by adiabatic calorimetry. ► The temperature dependence of vapour pressure determined by comparative ebulliometry. ► The thermodynamic functions derived from experiment and calculated by DFT method. ► Extending vapour pressure of moderate interval to entire region of liquid. ► An increment of the entropy of carbonyl group was defined from experimental data. - Abstract: The heat capacity of methyl n-butanoate in crystalline and liquid states was measured by vacuum adiabatic calorimetry over the temperature range from (8 to 372) K. The triple point temperature, the enthalpy and entropy of fusion, and the purity of the sample were determined. The saturated vapour pressure and the boiling temperatures were determined by comparative ebulliometry in the “atmospheric” pressure range 10.8 ⩽ (p/kPa) ⩽ 99.6. The normal boiling temperature, T n.b , and the enthalpy of vaporization at T = 298.15 K and T n.b were derived. The thermodynamic functions (absolute entropy and changes of the enthalpy, and Gibbs free energy) were derived for the solid and liquid states in the temperature range studied and for the ideal gas state at T = 298.15 K. The ideal gas heat capacities and the absolute entropies of methyl n-butanoate (MeBu) and ethyl propanoate (EtPr) were calculated by statistical thermodynamics on the basis of the molecular constants determined by the use of density functional theory on the B3LYP level. The experimental vapour pressure of MeBu and EtPr of moderate temperature intervals, Δ exp T = (59/65) K, were extended to the entire range of the liquids, Δ liq T = (364.7/345.7) K by the methods of the corresponding states law and simultaneous treatment of the pT-parameters and low-temperature heat capacities of the ideal gas and liquid, respectively. An additive contribution of the carbonyl group CO–(C, O) connected with C and O atoms was determined for calculation of the

21 CFR 172.872 - Methyl ethyl cellulose.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl ethyl cellulose. 172.872 Section 172.872... CONSUMPTION Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose... a cellulose ether having the general formula [C6H(10 -x-y)O5(CH3)x(C2H5)y]n, where x is the number...

Evolving artificial metalloenzymes via random mutagenesis

Science.gov (United States)

Yang, Hao; Swartz, Alan M.; Park, Hyun June; Srivastava, Poonam; Ellis-Guardiola, Ken; Upp, David M.; Lee, Gihoon; Belsare, Ketaki; Gu, Yifan; Zhang, Chen; Moellering, Raymond E.; Lewis, Jared C.

2018-03-01

Random mutagenesis has the potential to optimize the efficiency and selectivity of protein catalysts without requiring detailed knowledge of protein structure; however, introducing synthetic metal cofactors complicates the expression and screening of enzyme libraries, and activity arising from free cofactor must be eliminated. Here we report an efficient platform to create and screen libraries of artificial metalloenzymes (ArMs) via random mutagenesis, which we use to evolve highly selective dirhodium cyclopropanases. Error-prone PCR and combinatorial codon mutagenesis enabled multiplexed analysis of random mutations, including at sites distal to the putative ArM active site that are difficult to identify using targeted mutagenesis approaches. Variants that exhibited significantly improved selectivity for each of the cyclopropane product enantiomers were identified, and higher activity than previously reported ArM cyclopropanases obtained via targeted mutagenesis was also observed. This improved selectivity carried over to other dirhodium-catalysed transformations, including N-H, S-H and Si-H insertion, demonstrating that ArMs evolved for one reaction can serve as starting points to evolve catalysts for others.

High-affinity monoclonal antibodies specific for deoxynucleosides structurally modified by alkylating agents: Applications for immunoanalysis

International Nuclear Information System (INIS)

Adamkiewicz, J.; Ahrens, O.; Rajewsky, M.F.

1984-01-01

So far the results of attempts to use monoclonal antibodies for the demonstration of carcinogen-DNA adducts in cells by immunostaining have been promising. Thus the authors have established a standardized procedure for the quantitation of specific alkyl-deoxynucleosides in the nuclear DNA of individual cells by direct immunofluorescence, using tetramethylrhodamine isothiocyanate-labeled monoclonal antibodies and a computer-based image analysis of electronically intensified fluorescence signals. With a fluorescent anti-(O/sup 6/-EtdGuo) monoclonal antibody, the present detection limit for O/sup 6/-Etd-Guo in the nuclei of individual cells previously exposed to an ethylating N-nitroso compound (e.g., N-ethyl-N-nitrosourea) is -- 700 O/sup 6/-EtdGuo molecules per diploid genome, i.e., similar to the detection limit for the same ethylation product in a hydrolysate of (O/sup 6/-EtdGuo)-containing DNA analyzed by competitive RIA

Nitrosoureas: a review of experimental antitumor activity.

Science.gov (United States)

Schabel, F M

1976-06-01

The chemical class of drugs known as the nitrosoureas are a recently developed group of very active alkylating-agent anticancer drugs which are best represented by BCNU, CCNU, and methyl-CCNU (meCCNU). The nitrosoureas are among the most active, if not the most active, anticancer drugs both quantitatively (log kill of sensitive tumor cells in vivo) and qualitatively (spectrum of mouse, rat, and hamster tumors responding to treatment). Therapeutic anticancer activity of the nitrosoureas has been consistently observed with oral as well as parenteral administration. The nitrosoureas are clearly the most active group of anticancer drugs observed against experimental meningeal leukemias and intracerebrally implanted transplantable primary tumors of central nervous system origin (eg, gliomas, ependymoblastomas, and astrocytomas in mice and hamsters). The nitrosoureas have been observed to be less than additive in lethal toxicity for vital normal cells in the mouse in combination with representatives of the other major classes of anticancer agents, eg, purine antagonists, pyrimidine antagonists, inhibitors of DNA polymerase(s) or ribonucleotide reductase(s), mitotic inhibitors, drugs that bind to or intercalate with DNA, and other alkylating agents. Therapeutic synergism against one or more transplantable or spontaneous tumors of mice, rats, or hamsters with one of several nitrosoureas in two-drug combinations with representatives of most of the major classes of anticancer agents listed above has been reported. With a number of advanced-stages mouse tumors, generally considered to be refractory to treatment with most anticancer agents, long-term cures have been obtained with combination-drug or combined-modality (surgery plus chemotherapy) treatment. The demonstrated lack of cross-resistance of several leukemias and solid tumors of mice selected for resistance to BCNU, meCCNU, or other alkylating agents suggests that the widely held opinion that all alkylating agents are

Evaluation of genotoxic activity of maleic hydrazide, ethyl methane sulfonate, and N-nitroso diethylamine in Tradescantia.

Science.gov (United States)

Alvarez-Moya, C; Santerre-Lucas, A; Zúñiga-González, G; Torres-Bugarín, O; Padilla-Camberos, E; Feria-Velasco, A

2001-01-01

To assess the genotoxic activity of N-nitroso diethylamine (NDEA), maleic hydrazide (MH), and ethyl methane sulfonate (EMS) using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430). Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine (NDEA) at 1, 5, 10 mM, maleic hydrazide (MH) at 1, 5, 10 mM and ethyl methane sulfonate (EMS) at 15, 30 and 45 mM; and used in both pink mutation assay and comet assay using cellular nuclei from Tradescantia staminal hairs. The observation of staminal hair was realized along eight days (6-14) after treatment), flowers produced day 14 after treatment were utilized done according to Underbrink. In previous reports on plants, were comet assay was used, breaking cellular wall and separating by centrifugation gradient are necessary. Here, nuclei from staminal hairs were obtained by squashing the cells (is not necessary to utilize to break special procedure cellular wall), collected using a nylon mesh of 80 Mm and next the comet assay was applied. Student's T test was the statistical test used for analyzing the comet assay data. Both assays showed a great sensitivity to the studied mutagens. A relationship between the dose-pink event and the dose-tail length was evident. Even though the Tradescantia mutation assay is a sensitive test with MH and EMS, low doses of NDEA were not able to induce a significant increase in the pink event frequencies; however, the comet assay was able to detect the mutagenic effect of NDEA at the same dose. Thus, it is clear that the comet assay is highly sensitive to the lowest dose of chemical mutagens. The comet assay on nuclei from Tradescantia staminal hairs is a useful tool to monitor genotoxic agents; it is simple, highly sensitive, and faster than the pink mutation test.

Modification of a deoxynivalenol-antigen-mimicking nanobody to improve immunoassay sensitivity by site-saturation mutagenesis.

Science.gov (United States)

Qiu, Yu-Lou; He, Qing-Hua; Xu, Yang; Wang, Wei; Liu, Yuan-Yuan

2016-01-01

A nanobody (N-28) which can act as a deoxynivalenol (DON) antigen has been generated, and its residues Thr102-Ser106 were identified to bind with anti-DON monoclonal antibody by alanine-scanning mutagenesis. Site-saturation mutagenesis was used to analyze the plasticity of five residues and to improve the sensitivity of the N-28-based immunoassay. After mutagenesis, three mutants were selected by phage immunoassay and were sequenced. The half-maximal inhibitory concentrations of the immunoassay based on mutants N-28-T102Y, N-28-V103L, and N-28-Y105F were 24.49 ± 1.0, 51.83 ± 2.5, and 35.65 ± 1.6 ng/mL, respectively, showing the assay was, respectively, 3.2, 1.5, and 2.2 times more sensitive than the wild-type-based assay. The best mutant, N-28-T102Y, was used to develop a competitive phage ELISA to detect DON in cereals with high specificity and accuracy. In addition, the structural properties of N-28-T102Y and N-28 were investigated, revealing that the affinity of N-28-T102Y decreased because of increased steric hindrance with the large side chain. The lower-binding-affinity antigen mimetic may contribute to the improvement of the sensitivity of competitive immunoassays. These results demonstrate that nanobodies would be a favorable tool for engineering. Moreover, our results have laid a solid foundation for site-saturation mutagenesis of antigen-mimicking nanobodies to improve immunoassay sensitivity for small molecules.

Atom transfer radical polymerization of n-butyl acrylate catalyzed by atom transfer radical polymerization of n-butyl acrylate catalyzed by

NARCIS (Netherlands)

Zhang, H.; Linde, van der R.

2002-01-01

The homogeneous atom transfer radical polymerization (ATRP) of n-butyl acrylate with CuBr/N-(n-hexyl)-2-pyridylmethanimine as a catalyst and ethyl 2-bromoisobutyrate as an initiator was investigated. The kinetic plots of ln([M]0/[M]) versus the reaction time for the ATRP systems in different

Enhancement of nitrosourea cytotoxicity by misonidazole in vitro: correlation with carbamoylating potential.

Science.gov (United States)

Mulcahy, R. T.; Dembs, N. L.; Ublacker, G. A.

1984-01-01

We have investigated the relationships between nitrosourea structure and physicochemical properties and the ability of misonidazole (MISO) to potentiate nitrosourea cytotoxicity in an in vitro model system. EMT-6/Ro tumour cells were exposed in suspension to each of 9 different nitrosourea anti-tumour drugs under hypoxic and aerobic culture conditions. Additional cultures were similarly treated with nitrosoureas in the presence of 1.0 mM MISO. Seven of the 9 nitrosoureas did not demonstrate any selective toxicity toward aerobic or hypoxic cells. In contrast, chlorozotocin (CHLZ) was slightly more toxic toward hypoxic cells while Bis-OH CyNU more effectively killed aerobic cells. The addition of MISO to the drug treatment enhanced the effectiveness of all the nitrosoureas under hypoxic conditions, with the exception of CHLZ which was uninfluenced by MISO. The magnitude of the MISO dose enhancement factor (DEF, defined as the ratio of drug doses required to reduce cell survival to S = 10(-3) in 4 hours in the absence and presence of 1.0 mM MISO) for each combination was examined as a function of the relative carbamoylating or alkylating activity of the nitrosourea included in that combination. Such an analysis revealed a significant (P less than 0.05) positive correlation between relative carbamoylating potency and DEF. No significant (P greater than 0.20) relationship could be established for DEF and alkylating activity. PMID:6704305

Nitrosoureas in the Management of Malignant Gliomas.

Science.gov (United States)

Brandes, Alba A; Bartolotti, Marco; Tosoni, Alicia; Franceschi, Enrico

2016-02-01

Nitrosoureas represent one of the most active classes of agents in the treatment of high-grade gliomas and glioblastoma. In clinical practice, the most commonly used compounds are lomustine (either alone or in combination with procarbazine and vincristine), carmustine, and fotemustine. Given their toxicity profile and subsequent to the introduction of temozolomide in clinical practice, most of these agents were moved to the recurrent setting. This review focuses on the role of the nitrosoureas currently used in clinical practice for the treatment of malignant gliomas.

The effect of isoprenaline on induction of tumours by methyl nitrosourea in the salivary and mammary glands of female wistar rats.

Science.gov (United States)

Parkin, R.; Neale, S.

1976-01-01

Pretreatment of rats with isoprenaline sulphate (IPR) stimulated DNA synthesis in both salivary and mammary gland tissues. Salivary gland tumours induced by N-methyl-N-nitrosourea (MNU) were observed for the first time in rats, but occurred only in IPR-pretreated animals given MNU during the period of IPR-stimulated DNA synthesis. The cumulative index of MNU-induced mammary tumours and the number of tumours per tumour-bearing rat were increased by IPR-pretreament only if the animals received MNU during the period of IPR-stimulated DNA synthesis. PMID:974007

Heteropolyhedral silver compounds containing the polydentate ligand N,N,O-E-[6-(hydroxyimino)ethyl]-1,3,7-trimethyllumazine. Preparation, spectral and XRD structural study and AIM calculations.

Science.gov (United States)

Jiménez-Pulido, Sonia B; Hueso-Ureña, Francisco; Fernández-Liencres, M Paz; Fernández-Gómez, Manuel; Moreno-Carretero, Miguel N

2013-01-14

The oxime derived from 6-acetyl-1,3,7-trimethyllumazine (1) ((E-6-(hydroxyimino)ethyl)-1,3,7-trimethylpteridine-2,4(1H,3H)-dione, DLMAceMox) has been prepared and its molecular and crystal structure determined from spectral and XRD data. The oxime ligand was reacted with silver nitrate, perchlorate, thiocyanate, trifluoromethylsulfonate and tetrafluoroborate to give complexes with formulas [Ag(2)(DLMAceMox)(2)(NO(3))(2)](n) (2), [Ag(2)(DLMAceMox)(2)(ClO(4))(2)](n) (3), [Ag(2)(DLMAceMox)(2)(SCN)(2)] (4), [Ag(2)(DLMAceMox)(2)(CF(3)SO(3))(2)(CH(3)CH(2)OH)]·CH(3)CH(2)OH (5) and [Ag(DLMAceMox)(2)]BF(4) (6). Single-crystal XRD studies show that the asymmetrical residual unit of complexes 2, 3 and 5 contains two quite different but connected silver centers (Ag1-Ag2, 2.9-3.2 Å). In addition to this, the Ag1 ion displays coordination with the N5 and O4 atoms from both lumazine moieties and a ligand (nitrato, perchlorato or ethanol) bridging to another disilver unit. The Ag2 ion is coordinated to the N61 oxime nitrogens, a monodentate and a (O,O)-bridging nitrato/perchlorato or two monodentate O-trifluoromethylsulfonato anions. The coordination polyhedra can be best described as a strongly distorted octahedron (around Ag1) and a square-based pyramid (around Ag2). The Ag-N and Ag-O bond lengths range between 2.22-2.41 and 2.40-2.67 Å, respectively. Although the structure of 4 cannot be resolved by XRD, it is likely to be similar to those described for 2, 3 and 5, containing Ag-Ag units with S-thiocyanato terminal ligands. Finally, the structure of the tetrafluoroborate compound 6 is mononuclear with a strongly distorted tetrahedral AgN(4) core (Ag-N, 2.27-2.43 Å). Always, the different Ag-N distances found clearly point to the more basic character of the oxime N61 nitrogen atom when compared with the pyrazine N5 one. A topological analysis of the electron density within the framework provided by the quantum theory of atoms in molecules (QTAIM) using DFT(M06L) levels of

Quantitative evaluation of DNA damage and mutation rate by atmospheric and room-temperature plasma (ARTP) and conventional mutagenesis.

Science.gov (United States)

Zhang, Xue; Zhang, Chong; Zhou, Qian-Qian; Zhang, Xiao-Fei; Wang, Li-Yan; Chang, Hai-Bo; Li, He-Ping; Oda, Yoshimitsu; Xing, Xin-Hui

2015-07-01

DNA damage is the dominant source of mutation, which is the driving force of evolution. Therefore, it is important to quantitatively analyze the DNA damage caused by different mutagenesis methods, the subsequent mutation rates, and their relationship. Atmospheric and room temperature plasma (ARTP) mutagenesis has been used for the mutation breeding of more than 40 microorganisms. However, ARTP mutagenesis has not been quantitatively compared with conventional mutation methods. In this study, the umu test using a flow-cytometric analysis was developed to quantify the DNA damage in individual viable cells using Salmonella typhimurium NM2009 as the model strain and to determine the mutation rate. The newly developed method was used to evaluate four different mutagenesis systems: a new ARTP tool, ultraviolet radiation, 4-nitroquinoline-1-oxide (4-NQO), and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) mutagenesis. The mutation rate was proportional to the corresponding SOS response induced by DNA damage. ARTP caused greater DNA damage to individual living cells than the other conventional mutagenesis methods, and the mutation rate was also higher. By quantitatively comparing the DNA damage and consequent mutation rate after different types of mutagenesis, we have shown that ARTP is a potentially powerful mutagenesis tool with which to improve the characteristics of microbial cell factories.

Novel bifunctional anthracycline and nitrosourea chemotherapy for human bladder cancer: analysis in a preclinical survival model.

Science.gov (United States)

Glaves, D; Murray, M K; Raghavan, D

1996-08-01

A hybrid drug [N-2-chloroethylnitrosoureidodaunorubicin (AD312)] that combines structural and functional features of both anthracyclines and nitrosoureas was evaluated in a preclinical survival model of human bladder cancer. To measure the therapeutic activity of AD312, UCRU-BL13 transitional cell carcinoma cells were grown as xenografts in nude mice, and tumor growth rates were compared after i.v. administration of the drug at three dose levels. AD312 treatment at 45 and 60 mg/kg achieved 7-10-fold inhibition of tumor growth and increased host survival by 156 and 249%, respectively. Doses of 60 mg/kg showed optimal therapeutic efficacy, with sustained tumor growth inhibition, an over 2-fold increase in life span, and 40% of mice tumor free ("cured") at 120 days. Tumors were unresponsive to maximum tolerated doses of doxorubicin, a standard anthracycline used as a single agent and in combination therapies for bladder cancer. 1,3-Bis-[2-chloroethyl]-1-nitrosourea was used as a control for the apparently enhanced response of human tumors in murine hosts to nitrosoureas. 1, 3-Bis-[2-chloroethyl]-1-nitrosourea administered in three injections of 20 mg/kg did not cure mice but temporarily inhibited tumor growth by 70% and prolonged survival by 55%; its activity in this model suggests that it may be included in the repertoire of alkylating agents currently used for treatment of bladder cancers. AD312 showed increased antitumor activity with less toxicity than doxorubicin, and its bifunctional properties provide the opportunity for simultaneous treatment of individual cancer cells with two cytotoxic modalities as well as treatment of heterogeneous populations typical of bladder cancers. This novel cytotoxic drug cured doxorubicin-refractory disease and should be investigated for the clinical management of bladder cancer.

Identification of radiolytic products from N-nitrosodimethylamine and N-nitrosopyrrolidine by gas chromatography and mass spectrometry[Gamma irradiation; N-Nitrosodimethylamine; N-Nitrosopyrrolidine; Radiolysis

Energy Technology Data Exchange (ETDEWEB)

Ahn, H -J; Lee, C -H; Kim, J -H; Han, S -B; Jo, Cheorun; Kim, Sung; Byun, M -W

2004-01-01

The radiolytic products of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) dissolved in dichloromethane (DCM) were identified after gamma irradiation. The UV spectra of NDMA and NPYR indicated that irradiation reduced the typical peak of NDMA at 258 nm and NPYR at 260 nm.The major radiolytic components identified in irradiated NDMA were ethyl acetate and 2-dimethyl propanol. The irradiated NPYR dissolved in DCM and produced 2-butanone and 2-methyl-6-propyl piperidine as the major radiolytic components. 2-Methyl-6-propyl piperidine was the component detected in the greatest concentration in irradiated NPYR.

Cytostatic action of two nitrosoureas derived from cysteamine.

OpenAIRE

Bourut, C.; Chenu, E.; Godenèche, D.; Madelmont, J. C.; Maral, R.; Mathé, G.; Meyniel, G.

1986-01-01

2-Chloroethyl nitrosocarbamoylcystamine or ICIG-1325 (CNCC) is a lipid-soluble isomeric mixture of nitrosoureas. Its dose-effect relationship on L1210 leukaemia is characterized by a large maximally efficient dose-range (MEDR), greater than that of other nitrosoureas. CNCC also demonstrated significant therapeutic activity on intracerebrally (i.c.) transplanted L1210 leukaemia and on six transplanted solid tumours, TM2 mammary carcinoma, M555 ovarian carcinoma, B16 melanoma, glioma 26, 3LL, L...

A mutation in synaptojanin 2 causes progressive hearing loss in the ENU-mutagenised mouse strain Mozart.

Science.gov (United States)

Manji, Shehnaaz S M; Williams, Louise H; Miller, Kerry A; Ooms, Lisa M; Bahlo, Melanie; Mitchell, Christina A; Dahl, Hans-Henrik M

2011-03-15

Hearing impairment is the most common sensory impairment in humans, affecting 1:1,000 births. We have identified an ENU generated mouse mutant, Mozart, with recessively inherited, non-syndromic progressive hearing loss caused by a mutation in the synaptojanin 2 (Synj2), a central regulatory enzyme in the phosphoinositide-signaling cascade. The hearing loss in Mozart is caused by a p.Asn538Lys mutation in the catalytic domain of the inositol polyphosphate 5-phosphatase synaptojanin 2. Within the cochlea, Synj2 mRNA expression was detected in the inner and outer hair cells but not in the spiral ganglion. Synj2(N538K) mutant protein showed loss of lipid phosphatase activity, and was unable to degrade phosphoinositide signaling molecules. Mutant Mozart mice (Synj2(N538K/N538K)) exhibited progressive hearing loss and showed signs of hair cell degeneration as early as two weeks of age, with fusion of stereocilia followed by complete loss of hair bundles and ultimately loss of hair cells. No changes in vestibular or neurological function, or other clinical or behavioral manifestations were apparent. Phosphoinositides are membrane associated signaling molecules that regulate many cellular processes including cell death, proliferation, actin polymerization and ion channel activity. These results reveal Synj2 as a critical regulator of hair cell survival that is essential for hair cell maintenance and hearing function.

Instability of expanded simple tandem repeats is induced in cell culture by a variety of agents: N-Nitroso-N-ethylurea, benzo(a)pyrene, etoposide and okadaic acid

Energy Technology Data Exchange (ETDEWEB)

Polyzos, Aris [Environmental Health Centre, Environmental and occupational Toxicology Division, Health Canada, Tunney' s Pasture, P.L. 0803A, Ottawa, Ont., K1A 0L2 (Canada); Parfett, Craig [Environmental Health Centre, Environmental and occupational Toxicology Division, Health Canada, Tunney' s Pasture, P.L. 0803A, Ottawa, Ont., K1A 0L2 (Canada); Healy, Caroline [Environmental Health Centre, Environmental and occupational Toxicology Division, Health Canada, Tunney' s Pasture, P.L. 0803A, Ottawa, Ont., K1A 0L2 (Canada); Douglas, George R. [Environmental Health Centre, Environmental and occupational Toxicology Division, Health Canada, Tunney' s Pasture, P.L. 0803A, Ottawa, Ont., K1A 0L2 (Canada); Yauk, Carole L. [Environmental Health Centre, Environmental and occupational Toxicology Division, Health Canada, Tunney' s Pasture, P.L. 0803A, Ottawa, Ont., K1A 0L2 (Canada)]. E-mail: Carole_Yauk@hc-sc.gc.ca

2006-06-25

Expanded simple tandem repeat (ESTR) sequences have proven useful biomarkers to detect genotoxicity in vivo. Their high sensitivity has been used to assess environmentally relevant doses of mutagens such as ionizing radiation, DNA alkylating agents and airborne particulate pollution, for germline mutations in mouse assays. The mutagenic response involves size alteration of these ESTR loci induced by agents causing a variety of cellular damage. The mechanistic aspects of this induced instability remain unclear and have not been studied in detail. Mechanistic knowledge is important to help understand the relevance of increased ESTR mutation frequencies. In this study, we applied a murine cell culture system to examine induced response to four agents exhibiting different modes of toxic action including: N-nitroso-N-ethylurea (ENU), benzo(a)pyrene (BaP), okadaic acid and etoposide at slightly sub-toxic levels. We used single-molecule-polymerase chain reaction (SM-PCR) to assess the relative mutant frequency after 4-week chemical treatments at the Ms6-hm ESTR sequence of cultured C3H/10T1/2 cells (a mouse embryonic cell line). Increased mutation was observed with both 0.64 mM ENU (1.95-fold increase, P < 0.0001), 1 {mu}M benzo(a)pyrene (1.87-fold increase, P = 0.0006) and 3 nM etoposide (1.89-fold increase, P = 0.0003). The putative ESTR mutagen okadaic acid (1.27-fold increase, P = 0.2289), administered at 0.5 nM, did not affect the C3H/10T1/2 Ms6-hm locus. Therefore, agents inducing small and bulky adducts, and indirectly causing strand breaks through inhibition of topoisomerase, caused similar induction of instability at an ESTR locus at matched toxicities. As size spectra for induced mutations were identical, the data indicate that although these chemicals exhibit distinct modes of action, a similar indirect process is influencing ESTR instability. In contrast, a potent tumour promoter that is a kinase inhibitor does not contribute to induced ESTR instability in

Instability of expanded simple tandem repeats is induced in cell culture by a variety of agents: N-Nitroso-N-ethylurea, benzo(a)pyrene, etoposide and okadaic acid

International Nuclear Information System (INIS)

Polyzos, Aris; Parfett, Craig; Healy, Caroline; Douglas, George R.; Yauk, Carole L.

2006-01-01

Expanded simple tandem repeat (ESTR) sequences have proven useful biomarkers to detect genotoxicity in vivo. Their high sensitivity has been used to assess environmentally relevant doses of mutagens such as ionizing radiation, DNA alkylating agents and airborne particulate pollution, for germline mutations in mouse assays. The mutagenic response involves size alteration of these ESTR loci induced by agents causing a variety of cellular damage. The mechanistic aspects of this induced instability remain unclear and have not been studied in detail. Mechanistic knowledge is important to help understand the relevance of increased ESTR mutation frequencies. In this study, we applied a murine cell culture system to examine induced response to four agents exhibiting different modes of toxic action including: N-nitroso-N-ethylurea (ENU), benzo(a)pyrene (BaP), okadaic acid and etoposide at slightly sub-toxic levels. We used single-molecule-polymerase chain reaction (SM-PCR) to assess the relative mutant frequency after 4-week chemical treatments at the Ms6-hm ESTR sequence of cultured C3H/10T1/2 cells (a mouse embryonic cell line). Increased mutation was observed with both 0.64 mM ENU (1.95-fold increase, P < 0.0001), 1 μM benzo(a)pyrene (1.87-fold increase, P = 0.0006) and 3 nM etoposide (1.89-fold increase, P = 0.0003). The putative ESTR mutagen okadaic acid (1.27-fold increase, P = 0.2289), administered at 0.5 nM, did not affect the C3H/10T1/2 Ms6-hm locus. Therefore, agents inducing small and bulky adducts, and indirectly causing strand breaks through inhibition of topoisomerase, caused similar induction of instability at an ESTR locus at matched toxicities. As size spectra for induced mutations were identical, the data indicate that although these chemicals exhibit distinct modes of action, a similar indirect process is influencing ESTR instability. In contrast, a potent tumour promoter that is a kinase inhibitor does not contribute to induced ESTR instability in cell

N-glycosylation increases the circulatory half-life of human growth hormone

DEFF Research Database (Denmark)

Flintegaard, Thomas V; Thygesen, Peter; Rahbek-Nielsen, Henrik

2010-01-01

Therapeutic use of recombinant GH typically involves daily sc injections. We examined the possibilities for prolonging the in vivo circulation of GH by introducing N-glycans. Human GH variants with a single potential N-glycosylation site (N-X-S/T) introduced by site-directed mutagenesis were expr...

The ENU-3 protein family members function in the Wnt pathway parallel to UNC-6/Netrin to promote motor neuron axon outgrowth in C. elegans.

Science.gov (United States)

Florica, Roxana Oriana; Hipolito, Victoria; Bautista, Stephen; Anvari, Homa; Rapp, Chloe; El-Rass, Suzan; Asgharian, Alimohammad; Antonescu, Costin N; Killeen, Marie T

2017-10-01

The axons of the DA and DB classes of motor neurons fail to reach the dorsal cord in the absence of the guidance cue UNC-6/Netrin or its receptor UNC-5 in C. elegans. However, the axonal processes usually exit their cell bodies in the ventral cord in the absence of both molecules. Strains lacking functional versions of UNC-6 or UNC-5 have a low level of DA and DB motor neuron axon outgrowth defects. We found that mutations in the genes for all six of the ENU-3 proteins function to enhance the outgrowth defects of the DA and DB axons in strains lacking either UNC-6 or UNC-5. A mutation in the gene for the MIG-14/Wntless protein also enhances defects in a strain lacking either UNC-5 or UNC-6, suggesting that the ENU-3 and Wnt pathways function parallel to the Netrin pathway in directing motor neuron axon outgrowth. Our evidence suggests that the ENU-3 proteins are novel members of the Wnt pathway in nematodes. Five of the six members of the ENU-3 family are predicted to be single-pass trans-membrane proteins. The expression pattern of ENU-3.1 was consistent with plasma membrane localization. One family member, ENU-3.6, lacks the predicted signal peptide and the membrane-spanning domain. In HeLa cells ENU-3.6 had a cytoplasmic localization and caused actin dependent processes to appear. We conclude that the ENU-3 family proteins function in a pathway parallel to the UNC-6/Netrin pathway for motor neuron axon outgrowth, most likely in the Wnt pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Alleles conferring improved fiber quality from EMS mutagenesis of elite cotton genotypes

Science.gov (United States)

The elite gene pool of cotton (Gossypium spp.) has less diversity than those of most other major crops, making identification of novel alleles important to ongoing crop improvement. A total of 3,164 M5 lines resulting from ethyl methanesulfonate mutagenesis of two G. hirsutum breeding lines, TAM 94L...

Investigating N-Butanol and Ethyl Acetate Fractions of Nigella Sativa on Motoneurons’ Density of Spinal Cord Ventral Horn in Rats with Compressived Injury of Sciatic Nerve

Directory of Open Access Journals (Sweden)

M Ferdosi makan

2015-02-01

Methods: In this study, 24 Wistar male rats with average body weight of 250gr to 300gr were divided into four groups of six: control, compression, A(compression + n-butanol fraction 75mg/kg and B(compression+ethyl acetate fraction75mg/kg. In compression and treatment groups, sciatic nerve of the right leg underwent compression (30sec. In fact, the extract was injected intraperitoneally twice after the compression. After 28days, lumbar segments of spinal cord L2-L4 were sampled under perfusion method. After going through tissue processes, they were cut in serial sections (7µ, and stained with toluidine blue. Then, the density of alpha-motoneurons of spinal cord ventral horn was measured by using dissector method. Conclusion: The study findings revealed that n-butanol fraction of Nigella sativa caused an increase in neuronal density which posesses neuroprotective effects. This could be due to antioxidant and anti inflammatory effects of this herb. However, increases in neuronal density in ethyl acetate fraction didn’t prove to be significant.

Histological Characterization of the Dicer1 Mutant Zebrafish Retina

Directory of Open Access Journals (Sweden)

Saeed Akhtar

2015-01-01

Full Text Available DICER1, a multidomain RNase III endoribonuclease, plays a critical role in microRNA (miRNA and RNA-interference (RNAi functional pathways. Loss of Dicer1 affects different developmental processes. Dicer1 is essential for retinal development and maintenance. DICER1 was recently shown to have another function of silencing the toxicity of Alu RNAs in retinal pigment epithelium (RPE cells, which are involved in the pathogenesis of age related macular degeneration. In this study, we characterized a Dicer1 mutant fish line, which carries a nonsense mutation (W1457Ter induced by N-ethyl-N-nitrosourea mutagenesis. Zebrafish DICER1 protein is highly conserved in the evolution. Zebrafish Dicer1 is expressed at the earliest stages of zebrafish development and persists into late developmental stages; it is widely expressed in adult tissues. Homozygous Dicer1 mutant fish (DICER1W1457Ter/W1457Ter have an arrest in early growth with significantly smaller eyes and are dead at 14–18 dpf. Heterozygous Dicer1 mutant fish have similar retinal structure to that of control fish; the retinal pigment epithelium (RPE cells are normal with no sign of degeneration at the age of 20 months.

Evaluation of genotoxic activity of maleic hydrazide, ethyl methane sulfonate, and N-nitroso diethylamine in Tradescantia

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Alvarez-Moya Carlos

2001-01-01

Full Text Available Objective. To assess the genotoxic activity of N-nitroso diethylamine (NDEA, maleic hydrazide (MH, and ethyl methane sulfonate (EMS using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430. Material and Methods. Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine (NDEA at 1, 5, 10 mM, maleic hidrazide (MH at 1, 5, 10 mM and ethyl methane sulfonate (EMS at 15, 30 and 45 mM; and used in both pink mutation assay and comet assay using cellular nuclei from Tradescantia staminal hairs. The observation of staminal hair was realized along eight days (6-14 after treatment, flowers produced day 14 after treatment were utilized done according to Underbrink. In previous reports on plants, were comet assay was used, breaking cellular wall and separating by centrifugation gradient are necessary. Here, nuclei from staminal hairs were obtained by squashing the cells (is not necessary to utilize to break special procedure cellular wall, collected using a nylon mesh of 80Mm and next the comet assay was applied. Student's T test was the statistical test used for analyzing the comet assay data. Results. Both assays showed a great sensitivity to the studied mutagens. A relationship between the dose-pink event and the dose-tail length was evident. Even though the Tradescantia mutation assay is a sensitive test with MH and EMS, low doses of NDEA were not able to induce a significant increase in the pink event frequencies; however, the comet assay was able to detect the mutagenic effect of NDEA at the same dose. Thus, it is clear that the comet assay is highly sensitive to the lowest dose of chemical mutagens. Conclusions. The comet assay on nuclei from Tradescantia staminal hairs is a useful tool to monitor genotoxic agents; it is simple

Crystal structure and thermochemical properties of n-decylammonium ethyl sulfate (C10H21NH3SO4C2H5)(s)

International Nuclear Information System (INIS)

Zhang, Li-Jun; Di, You-Ying; Dou, Jian-Min

2013-01-01

Graphical abstract: Crystal structure of n-decylammonium ethyl sulfate was determined by X-ray crystallography. Lattice potential energy and molar volume of the solid compound and its anion were respectively obtained. Molar enthalpies of dissolution of the compound at different concentrations were measured by an isoperibol solution–reaction calorimeter. According to the Pitzer’s electrolyte solution theory, molar enthalpy of dissolution of the compound at infinite dilution and Pitzer parameters were obtained. The values of apparent relative molar enthalpies of the title compound and relative partial molar enthalpies of the solute and the solvent at different concentrations were derived. Finally, enthalpies of hydration of the compound and its anion were calculated. Highlights: ► Crystal structure of n-decylammonium ethyl sulfate was determined. ► Lattice potential energy was calculated. ► Molar enthalpy of dissolution at infinite dilution was determined. ► Enthalpies of hydration of the compound and its anion were derived. - Abstract: Crystal structure of n-decylammonium ethyl sulfate was determined by X-ray crystallography. Lattice potential energy and molar volume of the solid compound and its anion were respectively obtained. Ionic radius of the anion was calculated from the corresponding effective volume of the anion. Molar enthalpies of dissolution of the compound at different concentrations m /(mol · kg –1 ) were measured by an isoperibol solution–reaction calorimeter at T = 298.15 K. According to the Pitzer’s electrolyte solution theory, molar enthalpy of dissolution of the compound at infinite dilution (Δ sol H m ∞ ) was determined to be (21.284 ± 0.042) kJ·mol –1 , and enthalpy of hydration of the anion SO 4 C 2 H 5 − was calculated to be ΔH – = −340.68 kJ·mol –1 . The values of apparent relative molar enthalpies ( Φ L) of the title compound and relative partial molar enthalpies (L 2 ¯ and L 1 ¯ ) of the solute and

Potential neuroleptic agents. 4. Chemistry, behavioral pharmacology, and inhibition of [3H]spiperone binding of 3,5-disubstituted N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-methoxysalicylamides.

Science.gov (United States)

de Paulis, T; Kumar, Y; Johansson, L; Rämsby, S; Hall, H; Sällemark, M; Angeby-Möller, K; Ogren, S O

1986-01-01

A series of 3,5-disubstituted N-[(1-ethyl-2-pyrrolidinyl) methyl]-6-methoxysalicylamides was synthesized, starting from the 2,6-dimethoxybenzoic acids, by boron tribromide demethylation of the corresponding 3,5-disubstituted 2,6-dimethoxybenzamides and separation of the two positional isomers. The correct structure assignments were based on selective decoupling studies on their 13C NMR spectra. The salicylamide derivatives were tested for antidopamine activity in vivo by their ability to inhibit the apomorphine syndrome in the rat and in vitro by their ability to displace [3H]spiperone from striatal preparations of the rat brain. The activity seems to reside exclusively in the S enantiomer. Several compounds were considerably more potent than haloperidol, particularly those having an ethyl group in the 3-position and a halogen atom in the 5-position of the aromatic ring. The corresponding 5-alkyl-3-halogen-substituted compounds were much less active. A low acute toxicity was found for the most potent compounds. Some of the salicylamides displayed a 10-20-fold separation between the dose which blocks apomorphine-induced hyperactivity and that which blocks apomorphine-induced stereotypy. One compound, S-(-)-3,5-dichloro-N-[(1-ethyl-2-pyrrolidinyl) methyl]-6-methoxysalicylamide (raclopride, FLA 870) (13) had a stereotypy--hyperactivity separation more than twice that of sulpiride while being 100 times more potent in blocking the apomorphine effects. On this basis, 13 was selected for clinical trials against schizophrenia.

Mechanism of porcine liver xanthine oxidoreductase mediated N-oxide reduction of cyadox as revealed by docking and mutagenesis studies.

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Chigang Chen

Full Text Available Xanthine oxidoreductase (XOR is a cytoplasmic molybdenum-containing oxidoreductase, catalyzing both endogenous purines and exogenous compounds. It is suggested that XOR in porcine hepatocytes catalyzes the N-oxide reduction of quinoxaline 1,4-di-N-oxides (QdNOs. To elucidate the molecular mechanism underlying this metabolism, the cDNA of porcine XOR was cloned and heterologously expressed in Spodoptera frugiperda insect cells. The bovine XOR, showing sequence identity of 91% to porcine XOR, was employed as template for homology modeling. By docking cyadox, a representative compound of QdNOs, into porcine XOR model, eight amino acid residues, Gly47, Asn352, Ser360, Arg427, Asp430, Asp431, Ser1227 and Lys1230, were located at distances of less than 4Å to cyadox. Site-directed mutagenesis was performed to analyze their catalytic functions. Compared with wild type porcine XOR, G47A, S360P, D431A, S1227A, and K1230A displayed altered kinetic parameters in cyadox reduction, similarly to that in xanthine oxidation, indicating these mutations influenced electron-donating process of xanthine before subsequent electron transfer to cyadox to fulfill the N-oxide reduction. Differently, R427E and D430H, both located in the 424-434 loop, exhibited a much lower K(m and a decreased V(max respectively in cyadox reduction. Arg427 may be related to the substrate binding of porcine XOR to cyadox, and Asp430 is suggested to be involved in the transfer of electron to cyadox. This study initially reveals the possible catalytic mechanism of porcine XOR in cyadox metabolism, providing with novel insights into the structure-function relationship of XOR in the reduction of exogenous di-N-oxides.

Miscoding properties of 1,N{sup 6}-ethanoadenine, a DNA adduct derived from reaction with antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea

Energy Technology Data Exchange (ETDEWEB)

Hang, Bo; Guliaev, Anton B.; Chenna, Ahmed; Singer, B.

2003-03-05

1,N{sup 6}-Ethanoadenine (EA) is an exocyclic adduct formed from DNA reaction with the antitumor agent, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). To understand the role of this adduct in the mechanism of mutagenicity or carcinogenicity by BCNU, an oligonucleotide with a site-specific EA was synthesized using phosphoramidite chemistry. We now report the in vitro miscoding properties of EA in translesion DNA synthesis catalyzed by mammalian DNA polymerases (pols) {alpha}, {beta}, {eta} and {iota}. These data were also compared with those obtained for the structurally related exocyclic adduct, 1,N{sup 6}-ethenoadenine ({var_epsilon}A). Using a primer extension assay, both pols {alpha} and {beta} were primarily blocked by EA or {var_epsilon}A with very minor extension. Pol {eta} a member of the Y family of polymerases, was capable of catalyzing a significant amount of bypass across both adducts. Pol {eta} incorporated all four nucleotides opposite EA and {var_epsilon}A, but with differential preferences and mainly in an error-prone manner. Human pol {iota}, a paralog of human pol {eta}, was blocked by both adducts with a very small amount of synthesis past {var_epsilon}A. It incorporated C and, to a much lesser extent, T, opposite either adduct. In addition, the presence of an A adduct, e.g. {var_epsilon}A, could affect the specificity of pol {iota} toward the template T immediately 3 feet to the adduct. In conclusion, the four polymerases assayed on templates containing an EA or {var_epsilon}A showed differential bypass capacity and nucleotide incorporation specificity, with the two adducts not completely identical in influencing these properties. Although there was a measurable extent of error-free nucleotide incorporation, all these polymerases primarily misincorporated opposite EA, indicating that the adduct, similar to {var_epsilon}A, is a miscoding lesion.

Non-random alkylation of DNA sequences induced in vivo by chemical mutagens

Energy Technology Data Exchange (ETDEWEB)

Durante, M.; Geri, C.; Bonatti, S.; Parenti, R. (Universita di Pisa (Italy))

1989-08-01

Previous studies of the interaction of alkylating agents on the eukaryotic genome support the idea that induction of DNA adducts is at specific genomic sites. Here we show molecular and cytological evidence that alkylation is rather specific. Mammalian cell cultures were exposed to different doses of mutagens and the DNA was analyzed by density gradient ultracentrifugation, hydroxylapatite fractionation, and by restriction enzyme analysis. Studies with the labelled mutagens N-ethyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine show that there is a non-random distribution of the adducts. The adducts are found more frequently in A-T, G-C rich satellite DNA and highly repetitive sequences. Analysis with restriction enzymes shows that both methyl and ethyl groups influence the restriction patterns of the enzymes HpaII and MspI that recognize specific endogenous DNA methylation. These data suggest, as a subsequent mechanism, a modification in the pattern of the normal endogenous methylation of 5-methylcytosine.

DNA modification by sulfur mustards and nitrosoureas and repair of these lesions

International Nuclear Information System (INIS)

Ludlum, D.B.; Papirmeister, B.; Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD)

1986-01-01

The nature and significance of DNA modifications caused by chloroethyl ethyl sulfide (CEES) is compared with those produced by chloroethyl cyclohexyl nitrosourea (CCNU). This comparison illustrates the differences in the kind of biological response which can arise from DNA modification by different agents and the role of DNA repair in determining this response. In particular, the ability of tumor cells to become resistant to therapeutic agents has some important implications for the ability of cells in general to tolerate environmental mutagens. DNA modification by CEES and CCNU can be viewed in the context of DNA modification caused by compounds which naturally react with DNA. For example, cycasin and S-adenosylmethionine both methylate DNA. Not surprisingly, a variety of repair mechanisms has evolved which serve to maintain the integrity of DNA in the presence of such naturally-occurring DNA modifiers. The ability of these enzymes to repair other DNA lesions is currently under active investigation as described here. 19 refs., 4 figs., 3 tabs

Evaluation of genotoxic activity of maleic hydrazide, ethyl methane sulfonate, and N-nitroso diethylamine in Tradescantia Evaluación de la genotoxicidad de hidrazida málica, N-nitroso dietilamina, y etil metano sulfonato, en núcleos de Tradescantia, por medio de la prueba del cometa

Directory of Open Access Journals (Sweden)

Carlos Alvarez-Moya

2001-12-01

Full Text Available Objective. To assess the genotoxic activity of N-nitroso diethylamine (NDEA, maleic hydrazide (MH, and ethyl methane sulfonate (EMS using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430. Material and Methods. Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine (NDEA at 1, 5, 10 mM, maleic hidrazide (MH at 1, 5, 10 mM and ethyl methane sulfonate (EMS at 15, 30 and 45 mM; and used in both pink mutation assay and comet assay using cellular nuclei from Tradescantia staminal hairs. The observation of staminal hair was realized along eight days (6-14 after treatment, flowers produced day 14 after treatment were utilized done according to Underbrink. In previous reports on plants, were comet assay was used, breaking cellular wall and separating by centrifugation gradient are necessary. Here, nuclei from staminal hairs were obtained by squashing the cells (is not necessary to utilize to break special procedure cellular wall, collected using a nylon mesh of 80Mm and next the comet assay was applied. Student's T test was the statistical test used for analyzing the comet assay data. Results. Both assays showed a great sensitivity to the studied mutagens. A relationship between the dose-pink event and the dose-tail length was evident. Even though the Tradescantia mutation assay is a sensitive test with MH and EMS, low doses of NDEA were not able to induce a significant increase in the pink event frequencies; however, the comet assay was able to detect the mutagenic effect of NDEA at the same dose. Thus, it is clear that the comet assay is highly sensitive to the lowest dose of chemical mutagens. Conclusions. The comet assay on nuclei from Tradescantia staminal hairs is a useful tool to monitor genotoxic agents; it is simple

Solvation of ionic liquids based on N-alkyl-N-methylmorpholinium cations in N,N-dimethylformamide and dimethyl sulfoxide – A volumetric and acoustic study

International Nuclear Information System (INIS)

Marcinkowski, Łukasz; Szepiński, Emil; Kloskowski, Adam; Namieśnik, Jacek; Warmińska, Dorota

2017-01-01

Highlights: • V ϕ of DMSO and DMF solutions of [Mor1,R][BF 4 ] increase with increasing IL concentration at all investigated temperatures. • Ion–ion interaction are stronger for DMF solutions than corresponding for DMSO. • DMSO interacts more effectively with ionic liquids studied than DMF. • Obtained results are the consequence of the cation size of the ionic liquid. - Abstract: Apparent molar volumes and molar isentropic compressibilities for N-ethyl-N-methylmorpholinium and N-decyl-N-methylmorpholinium tetrafluoroborates in N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) have been determined from density and speed of sound measurements over the temperature range T = (298.15, 303.15, 308.15, 313.15, 318.15 and 328.15) K at experimental pressure p = 0.1 MPa. This data has been used to calculate partial molar volumes and partial molar isentropic compressibilities at infinite dilution. The partial molar expansion coefficients and their secondary derivative have been estimated as well. The obtained results indicate that dimethyl sulfoxide interacts more effectively with ionic liquids studied than N,N-dimetylformamide and ion–ion interaction are stronger for N,N-dimetylformamide solutions than corresponding in dimethyl sulfoxide. Moreover the temperature dependence of the limiting apparent molar volumes and compressibilities is a result of temperature influence on the electrostriction effect, the ordering of a bulk solvent and number solvent molecules in the nearest presence of the salt.

A contribution to the study of the extraction of mineral acids and of actinide (IV) and (VI) cations by N,N-dialkylamides

International Nuclear Information System (INIS)

Condamines, N.

1990-03-01

N,N-dialkylamides are alternate extractants to tributylphosphate, TBP, for the actinides separation in nuclear fuel reprocessing. N,N-di (2-ethyl hexyl) butyramide and N,N-di (2 ethyl hexyl) isobutyramide are selected for their sufficient extraction and partition ability towards actinides (IV) and (VI) without coextracting fission products. Mechanisms of HNO 3 , UO 2 2+ , Pu 4+ , Th 4+ are investigated. Nitric acid extraction is due to the competitive formation of the species (HNO 3 )L 2 , (HNO 3 )L, (HNO 3 ) 2 L (L: DOBA or DOiBA). An hydrogen bond is the driving force of the transfer. For low acidity media, amides are neutral extractants. Physical interactions, between free ligand and metallic complex, arise for high amide concentrations. Taking into account the non-ideality of the organic medium by a hard spheres mixture model, we estimate that such interactions are far from negligible and very specific to the amide group. Unlike TBP, when increasing acidity, amides behave as anionic extractants. DOBA and DOiBA appear to be satisfactory extractants for fuel reprocessing [fr

B-1a transitional cells are phenotypically distinct and are lacking in mice deficient in IκBNS

Science.gov (United States)

Pedersen, Gabriel K.; Àdori, Monika; Khoenkhoen, Sharesta; Dosenovic, Pia; Beutler, Bruce; Karlsson Hedestam, Gunilla B.

2014-01-01

B-1 cells mediate early protection against infection by responding to T cell-independent (TI) antigens found on the surface of various pathogens. Mice with impaired expression of the atypical IκB protein IκBNS have markedly reduced frequencies of B-1 cells. We used a mouse strain with dysfunctional IκBNS derived from an N-ethyl-N-nitrosourea (ENU) screen, named bumble, to investigate the point in the development of B-1 cells where IκBNS is required. The presence of wild-type (wt) peritoneal cells in mixed wt/bumble chimeras did not rescue the development of bumble B-1 cells, but wt peritoneal cells transferred to bumble mice restored natural IgM levels and response to TI antigens. The bumble and wt mice displayed similar levels of fetal liver B-1 progenitors and splenic neonatal transitional B (TrB) cells, both of which were previously shown to give rise to B-1 cells. Interestingly, we found that a subset of wt neonatal TrB cells expressed common B-1a markers (TrB-1a) and that this cell population was absent in the bumble neonatal spleen. Sorted TrB-1a (CD93+IgM+CD5+) cells exclusively generated B-1a cells when adoptively transferred, whereas sorted CD93+IgM+CD5− cells gave rise to B-2 cells and, to a lesser extent, B-1b and B-1a cells. This study identifies a phenotypically distinct splenic population of TrB-1a cells and establishes that the development of B-1a cells is blocked before this stage in the absence of IκBNS. PMID:25228759

Labeling of BCNU with 11C and 13N and its in vivo pharmacokinetics study with PET

International Nuclear Information System (INIS)

Diksic, M.; Farrokhzad, S.; Yamamoto, L.; Feindel, W.

1982-01-01

1,3-bis(2-chloroethyl)-1-nitrosourea(BCNU) is an antitumor drug. 13 N and 11 C labeled BCNU were synthesized and made suitable for in vivo studies with positron emission tomography (PET). The optimization of the labeling procedures were discussed with an emphasis on the radiochemical yield and specific activity of the final product

Male Hypogonadism and Germ Cell Loss Caused by a Mutation in Polo-Like Kinase 4

Science.gov (United States)

Harris, Rebecca M.; Weiss, Jeffrey

2011-01-01

The genetic etiologies of male infertility remain largely unknown. To identify genes potentially involved in spermatogenesis and male infertility, we performed genome-wide mutagenesis in mice with N-ethyl-N-nitrosourea and identified a line with dominant hypogonadism and patchy germ cell loss. Genomic mapping and DNA sequence analysis identified a novel heterozygous missense mutation in the kinase domain of Polo-like kinase 4 (Plk4), altering an isoleucine to asparagine at residue 242 (I242N). Genetic complementation studies using a gene trap line with disruption in the Plk4 locus confirmed that the putative Plk4 missense mutation was causative. Plk4 is known to be involved in centriole formation and cell cycle progression. However, a specific role in mammalian spermatogenesis has not been examined. PLK4 was highly expressed in the testes both pre- and postnatally. In the adult, PLK4 expression was first detected in stage VIII pachytene spermatocytes and was present through step 16 elongated spermatids. Because the homozygous Plk4I242N/I242N mutation was embryonic lethal, all analyses were performed using the heterozygous Plk4+/I242N mice. Testis size was reduced by 17%, and histology revealed discrete regions of germ cell loss, leaving only Sertoli cells in these defective tubules. Testis cord formation (embryonic day 13.5) was normal. Testis histology was also normal at postnatal day (P)1, but germ cell loss was detected at P10 and subsequent ages. We conclude that the I242N heterozygous mutation in PLK4 is causative for patchy germ cell loss beginning at P10, suggesting a role for PLK4 during the initiation of spermatogenesis. PMID:21791561

Effects of growth temperature and caffeine on genetic responses of Candida albicans to ethyl methanesulfonate, nitrous acid and ultraviolet radiation

International Nuclear Information System (INIS)

Sarachek, A.; Bish, J.T.

1976-01-01

Ultraviolet radiation is more effective than either ethyl methanesulfonate or nitrous acid in inducing reverse mutation from auxotrophy to prototrophy in C. albicans. The killing effect of each of the mutagens is greater for cells grown at 37 C than at 25 C after treatment; mutation frequencies are unaffected by post-treatment growth temperatures. Though caffeine depresses survival of mutagen treated cells at both 25 C or 37 C, its effect is more pronounced at 37 C. Caffeine has no effect on mutagenesis by nitrous acid or ethyl methanesulfonate; it depresses UV mutagenesis, but only at 37 C and at high UV dosages. These findings indicate that UV mutagenesis in C. albicans is mediated by a caffeine-sensitive, recombinational system for DNA repair analogous to those known to occur in other species of yeast. The repair of C. albicans is unique in being susceptible to caffeine only at high temperature and when the number of DNA lesions to be repaired is large. The caffeine sensitive steps in repair critical to UV mutagenesis are not involved in fixing mutations induced by the chemical mutagens tested

A contribution to the study of the extraction of mineral acids and of actinide (IV) and (VI) cations by N,N-dialkylamides; Contribution a l'etude de l'extraction d'acides mineraux et de cations actinides aux degres d'oxydation (IV) et (VI) par des N,N-dialkylamides

Energy Technology Data Exchange (ETDEWEB)

Condamines, N

1990-03-15

N,N-dialkylamides are alternate extractants to tributylphosphate, TBP, for the actinides separation in nuclear fuel reprocessing. N,N-di (2-ethyl hexyl) butyramide and N,N-di (2 ethyl hexyl) isobutyramide are selected for their sufficient extraction and partition ability towards actinides (IV) and (VI) without coextracting fission products. Mechanisms of HNO{sub 3}, UO{sub 2}{sup 2+}, Pu{sup 4+}, Th{sup 4+} are investigated. Nitric acid extraction is due to the competitive formation of the species (HNO{sub 3})L{sub 2}, (HNO{sub 3})L, (HNO{sub 3}){sub 2}L (L: DOBA or DOiBA). An hydrogen bond is the driving force of the transfer. For low acidity media, amides are neutral extractants. Physical interactions, between free ligand and metallic complex, arise for high amide concentrations. Taking into account the non-ideality of the organic medium by a hard spheres mixture model, we estimate that such interactions are far from negligible and very specific to the amide group. Unlike TBP, when increasing acidity, amides behave as anionic extractants. DOBA and DOiBA appear to be satisfactory extractants for fuel reprocessing.

Acquisition of resistance to 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride in V79 cells through increased removal of O6-alkylguanine.

Science.gov (United States)

Satoh, M S; Huh, N H; Horie, Y; Thomale, J; Rajewsky, M F; Kuroki, T

1987-10-01

The molecular mechanism of acquisition of resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride (ACNU) was investigated using ACNU-resistant clones (ACNUr-1-4) isolated from the V79 cell line. The binding level of alkyl cyanate, a decomposition product of ACNU, to protein in ACNUr-1 cells was not less than that in the parental V79 cells, indicating that the acquired resistance was not due to a reduced intracellular concentration of ACNU. Because O6-chloroethylguanine, an intermediate in cytotoxic interstrand cross-link formation by ACNU, is known to be repaired by the same mechanism as O6-ethyldeoxyguanosine (O6-EtdGuo), we quantitated O6-EtdGuo by radioimmunoassay at various times after exposure of cells to 100 micrograms/ml N-ethyl-N-nitrosourea for 20 min. In V79 cells, elimination of O6-EtdGuo was negligible, but in all four resistant clones, 30 to 59% of the O6-EtdGuo was removed within 24 hr after exposure. This increased removal of O6-EtdGuo among the resistant clones was associated with the activity of O6-alkylguanine DNA alkyltransferase (O6-AGT) determined using cell extracts. The present results indicate that increased removal of O6-chloroethylguanine in ACNU-resistant clones by O6-AGT is mechanistically linked to the acquisition of resistance to ACNU.

Transgenic Chinese hamster V79 cell lines which exhibit variable levels of gpt mutagenesis

International Nuclear Information System (INIS)

Klein, C.B.; Rossman, T.G.

1990-01-01

The Escherichia coli gpt gene coding for xanthine-guanine phosphoribosyl transferase has been stably transfected into HPRT - Chinese hamster V79 cells. Several gpt - cell lines have been established, which retain the sequence(s) even after long-term culture without selection for gpt. While spontaneous mutagenesis to gpt - occurs rather frequently for most cell lines, it cannot be correlated with either the number of plasmid integration sites or deletion of the plasmid sequence(s). One transgenic cell line (g12), which continuously maintains a low spontaneous mutation frequency was used in comparative mutagenesis studies with wild-type V79 cells (gpt vs. hprt). Alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and β-propiolactone (BPL) are shown to be equally toxic and mutagenic in both g12 and V79 cells. UV and X-rays are also equally toxic to both cell lines. The data presented here suggests that g12 cells may be useful to study mammalian mutagenesis by agents which yield limited response at the hprt locus

Conformational states of N-acylalanine dithio esters: correlation of resonance Raman spectra with structures

International Nuclear Information System (INIS)

Lee, H.; Angus, R.H.; Storer, A.C.; Varughese, K.I.; Carey, P.R.

1988-01-01

The conformational states of N-acylalanine dithio esters, involving rotational isomers about the RC(=O)NH-CH(CH 3 ) and NHCH(CH 3 )-C(=S) bonds, are defined and compared to those of N-acylglycine dithio esters. The structure of N-(p-nitrobenzoyl)-DL-alanine ethyl dithio ester has been determined by X-ray crystallographic analysis; it is a B-type conformer with the amide N atom cis to the thiol sulfur. Raman and resonance Raman (RR) measurements on this compound and for the B conformers of solid N-benzoyl-DL-alanine ethyl dithio ester and N-(β-phenylpropionyl)-DL-alanine ethyl dithio ester and its NHCH(CD 3 )C(=S) and NHCH(CH 3 ) 13 C(=S) analogues are used to set up a library of RR data for alanine-based dithio esters in a B-conformer state. RR data for this solid material in its isotopically unsubstituted and CH(C-D 3 )C(=S) and CH(CH 3 ) 13 C(=S) forms provide information on the RR signatures of alanine dithio esters in A-like conformations. RR spectra are compared for the solid compounds, for N-(p-nitrobenzoyl)-DL-alanine, N-(β-phenylpropionyl)-DL-alanine, and (methyloxycarbonyl)-L-phenylalanyl-DL-alanine ethyl dithio ester, and for several 13 C=S- and CD 3 -substituted analogues in CCl 4 or aqueous solutions. The RR data demonstrate that the alanine-based dithio esters take up A, B, and C 5 conformations in solution. The RR spectra of these conformers are clearly distinguishable from those for the same conformers of N-acylglycine dithio esters. However, the crystallographic and spectroscopic results show that the results show that the conformational properties of N-acylglycine and N-acylalanine dithio esters are very similar

Synthesis of [14C]-62514, a radiolabelled derivative of erythromycin A, via [2-14C]N,N-dimethylethylenediamine

International Nuclear Information System (INIS)

Surber, B.W.; Baker, W.R.; Seif, L.

1991-01-01

The synthesis of [ 14 C]A-62514, 11-deoxy-11[carboxy(2-dimethylamino-[1- 14 C]ethyl)amino]-6-0-methyl-e rythromycin A 11,12-(cyclic ester), was performed in five steps. The key intermediate, [2- 14 C]N,N-dimethylethyl-enediamine, was obtained in 80% yield by reacting Eschenmoser's salt with K 14 CN and reducing the resulting [1- 14 C]N,N-dimethylglycinonitrile with H 2 and Raney Ni in methanol and ammonium hydroxide. The final product was obtained 97% radiochemically pure in an overall radiochemical yield of 14%, with a specific activity of 39 mCi/mmol. (author)

DNA crosslinking and cytotoxicity in normal and transformed human cells treated with antitumor nitrosoureas.

OpenAIRE

Erickson, L C; Bradley, M O; Ducore, J M; Ewig, R A; Kohn, K W

1980-01-01

Normal (IMR-90) and simian virus 40-transformed (VA-13) human embryo cells were treated with antitumor nitrosoureas, and the effects on cell viability and cell DNA were compared. All six nitrosoureas tested were more toxic to VA-13 cells than to IMR-90 cells as measured by decrease in cell proliferation or in colony formation. The nitrosoureas capable of generating alkylisocyanates produced a smaller difference between the cell types than did derivatives lacking this capacity. DNA damage was ...

Targeted mutagenesis using CRISPR/Cas in inbred potatoes

Science.gov (United States)

Targeted mutagenesis using sequence-specific nucleases (SSNs) has been well established in several important crop species, but is in need of improvement in potato (Solanum tuberosum L.). For over a century, potatoes have been bred as autotetraploids (2n = 4x = 48), relying on F1 selections and clona...

Destruction of carcinogenic and mutagenic N-nitrosamides in laboratory wastes

Energy Technology Data Exchange (ETDEWEB)

Lunn, G.; Sansone, E.B.; Andrews, A.W.; Castegnaro, M.; Malaveille, C.; Michelon, J.; Brouet, I.; Keefer, L.K.

1984-01-01

The chemical degradation of five N-nitrosamides used widely for the experimental induction of cancer has been studied with the goal of identifying, and experimentally validating, reliable methods that can be recommended for the destruction of carcinogenic N-nitrosoureas and related compounds in laboratory wastes. Although data are not yet complete, preliminary evidence indicates that none of the five methods studied thus far is ideal for hazard-control purposes. Decomposition with 1 mol/L potassium hydroxide solution destroyed the N-nitrosamides, but generated diazoalkanes, which are carcinogenic, toxic and potentially explosive. Treatment with strong acid in the presence of sulfamic acid or iron filings completely decomposed all N-nitrosamides without forming diazoalkanes, but failed in the presence of solvents which were immiscible with water. Cleavage with hydrogen bromide in glacial acetic acid proceeded to a point of maximum degradation, following which gradual reformation of the N-nitrosamide was observed. Permanganate oxidation was effective in sulfuric acid solution, but was incomplete when an alcohol or dimethyl sulfoxide was present. Salmonella typhimurium tester strains TA1535, TA1530 and TA100, detected mutagenic degradation products in each of the destruction methods, with the exception of the hydrobromic acid/acetic acid procedure.

Preventive effect of Oenothera rosea on N-methyl-N-nitrosourea-(NMU) induced gastric cancer in rats

OpenAIRE

Almora-Pinedo, Yuan; Arroyo-Acevedo, Jorge; Herrera-Calderon, Oscar; Chumpitaz-Cerrate, Víctor; Hañari-Quispe, Renán; Tinco-Jayo, Aldo; Franco-Quino, Cesar; Figueroa-Salvador, Linder

2017-01-01

Yuan Almora-Pinedo,1 Jorge Arroyo-Acevedo,2 Oscar Herrera-Calderon,3 Víctor Chumpitaz-Cerrate,4 Renán Hañari-Quispe,5 Aldo Tinco-Jayo,6 Cesar Franco-Quino,4 Linder Figueroa-Salvador7 1Department of Pharmacy, Hospital Nacional Hipólito Unanue, Lima, 2Laboratory of Experimental Pharmacology, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, 3Faculty of Pharmacy and Biochemistry, Universidad Nacional San Luis Gonzaga de Ica, Ica, 4La...

Preparation of 15N-13C-fulminic acid

International Nuclear Information System (INIS)

Wilmes, R.; Winnewisser, M.

1993-01-01

The precursor for the title compound was prepared in a three-step synthesis. The 13 C-label was incorporated in the first step employing 2- 13 C-ethyl acetate and the 15 N-label in the last step, using 15 N-sodium nitrite. Upon pyrolysis the precursor forms three fragments, one of them being the title compound. (Author)

Crystallographic characterization of single-ortho, N-substituted acetanilide derivatives

International Nuclear Information System (INIS)

Boeyens, J.C.A.; Denner, L.; Painter, S.; Staskun, B.

1987-01-01

The crystal and molecular structures of the three single-ortho, N-substituted amide derivatives, acet-2'-bromo-N-(p-nitrobenzyl)anilide, 3',5'-dimethyl-N-ethyl-2,2,2',4'-tetrachlorobenzoylacetanilide, and difluoro[(1-phenyl-2-(o-ethylphenyl-N-benzylcarbamoyl)vinyl)oxy]borane, have been determined by X-ray diffraction analysis. In each case, the amide carbonyl group was found in the exo-conformation, independent of the nature of the acyl group. The observed conformations correlate well with solution structures, inferred from n.m.r. data

ER stress-mediated apoptosis in a new mouse model of osteogenesis imperfecta.

Directory of Open Access Journals (Sweden)

Thomas S Lisse

2008-02-01

Full Text Available Osteogenesis imperfecta is an inherited disorder characterized by increased bone fragility, fractures, and osteoporosis, and most cases are caused by mutations affecting the type I collagen genes. Here, we describe a new mouse model for Osteogenesis imperfecta termed Aga2 (abnormal gait 2 that was isolated from the Munich N-ethyl-N-nitrosourea mutagenesis program and exhibited phenotypic variability, including reduced bone mass, multiple fractures, and early lethality. The causal gene was mapped to Chromosome 11 by linkage analysis, and a C-terminal frameshift mutation was identified in the Col1a1 (procollagen type I, alpha 1 gene as the cause of the disorder. Aga2 heterozygous animals had markedly increased bone turnover and a disrupted native collagen network. Further studies showed that abnormal proalpha1(I chains accumulated intracellularly in Aga2/+ dermal fibroblasts and were poorly secreted extracellularly. This was associated with the induction of an endoplasmic reticulum stress-specific unfolded protein response involving upregulation of BiP, Hsp47, and Gadd153 with caspases-12 and -3 activation and apoptosis of osteoblasts both in vitro and in vivo. These studies resulted in the identification of a new model for Osteogenesis imperfecta, and identified a role for intracellular modulation of the endoplasmic reticulum stress-associated unfolded protein response machinery toward osteoblast apoptosis during the pathogenesis of disease.

Nitrosoureas inhibit the stathmin-mediated migration and invasion of malignant glioma cells.

Science.gov (United States)

Liang, Xing-Jie; Choi, Yong; Sackett, Dan L; Park, John K

2008-07-01

Malignant gliomas are the most common primary intrinsic brain tumors and are highly lethal. The widespread migration and invasion of neoplastic cells from the initial site of tumor formation into the surrounding brain render these lesions refractory to definitive surgical treatment. Stathmin, a microtubule-destabilizing protein that mediates cell cycle progression, can also regulate directed cell movement. Nitrosoureas, traditionally viewed as DNA alkylating agents, can also covalently modify proteins such as stathmin. We therefore sought to establish a role for stathmin in malignant glioma cell motility, migration, and invasion and determine the effects of nitrosoureas on these cell movement-related processes. Scratch wound-healing recovery, Boyden chamber migration, Matrigel invasion, and organotypic slice invasion assays were performed before and after the down-regulation of cellular stathmin levels and in the absence and presence of sublethal nitrosourea ([1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea]; CCNU) concentrations. We show that decreases in stathmin expression lead to significant decreases in malignant glioma cell motility, migration, and invasion. CCNU, at a concentration of 10 micromol/L, causes similar significant decreases, even in the absence of any effects on cell viability. The direct inhibition of stathmin by CCNU is likely a contributing factor. These findings suggest that the inhibition of stathmin expression and function may be useful in limiting the spread of malignant gliomas within the brain, and that nitrosoureas may have therapeutic benefits in addition to their antiproliferative effects.

Nitrosoureas Inhibit the Stathmin Mediated Migration and Invasion of Malignant Glioma Cells

Science.gov (United States)

Liang, Xing-Jie; Choi, Yong; Sackett, Dan L.; Park, John K.

2008-01-01

Malignant gliomas are the most common primary intrinsic brain tumors and are highly lethal. The widespread migration and invasion of neoplastic cells from the initial site of tumor formation into the surrounding brain render these lesions refractory to definitive surgical treatment. Stathmin, a microtubule destabilizing protein that mediates cell cycle progression, can also regulate directed cell movement. Nitrosoureas, traditionally viewed as DNA alkylating agents, can also covalently modify proteins such as stathmin. We therefore sought to establish a role for stathmin in malignant glioma cell motility, migration, and invasion and determine the effects of nitrosoureas on these cell movement related processes. Scratch-wound healing recovery, Boyden chamber migration, Matrigel invasion, and organotypic slice invasion assays were performed before and after the down regulation of cellular stathmin levels and in the absence and presence of sub-lethal nitrosourea (CCNU; [1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea]) concentrations. We demonstrate that decreases in stathmin expression lead to significant decreases in malignant glioma cell motility, migration, and invasion. CCNU, at a concentration of 10 μM, causes similar significant decreases, even in the absence of any effects on cell viability. The direct inhibition of stathmin by CCNU is likely a contributing factor. These findings suggest that the inhibition of stathmin expression and function may be useful in limiting the spread of malignant gliomas within the brain and that nitrosoureas may have therapeutic benefits in addition to their anti-proliferative effects. PMID:18593927

Interference with effects of amphotericin B on Candida albicans cells by 2-chloroethyl-1-nitrosoureas.

OpenAIRE

Brajtburg, J; Elberg, S; Kobayashi, G S; Medoff, G

1988-01-01

Two nitrosoureas, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) and 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), with strong carbamoylating and weak alkylating activities, interfered with the induction of potassium leakage and lethal action of amphotericin B (AmB) on Candida albicans. 2-Cyclohexyl isocyanate, the product of decomposition of CCNU, and 2-chloroethyl isocyanate, the product of decomposition of BCNU, also interfered with the anticandidal actions of AmB. In contrast, two ni...

Fluorescence-Based Reporters for Detection of Mutagenesis in E. coli.

Science.gov (United States)

Standley, Melissa; Allen, Jennifer; Cervantes, Layla; Lilly, Joshua; Camps, Manel

2017-01-01

Mutagenesis in model organisms following exposure to chemicals is used as an indicator of genotoxicity. Mutagenesis assays are also used to study mechanisms of DNA homeostasis. This chapter focuses on detection of mutagenesis in prokaryotes, which boils down to two approaches: reporter inactivation (forward mutation assay) and reversion of an inactivating mutation (reversion mutation assay). Both methods are labor intensive, involving visual screening, quantification of colonies on solid media, or determining a Poisson distribution in liquid culture. Here, we present two reversion reporters for in vivo mutagenesis that produce a quantitative output, and thus have the potential to greatly reduce the amount of test chemical and labor involved in these assays. This output is obtained by coupling a TEM β lactamase-based reversion assay with GFP fluorescence, either by placing the two genes on the same plasmid or by fusing them translationally and interrupting the N-terminus of the chimeric ORF with a stop codon. We also describe a reporter aimed at facilitating the monitoring of continuous mutagenesis in mutator strains. This reporter couples two reversion markers, allowing the temporal separation of mutation events in time, thus providing information about the dynamics of mutagenesis in mutator strains. Here, we describe these reporter systems, provide protocols for use, and demonstrate their key functional features using error-prone Pol I mutagenesis as a source of mutations. © 2017 Elsevier Inc. All rights reserved.

The total body mass of fatty acid ethyl esters in skeletal muscles following ethanol exposure greatly exceeds that found in the liver and the heart.

Science.gov (United States)

Salem, Raneem O; Laposata, Michael; Rajendram, Rajkumar; Cluette-Brown, Joanne E; Preedy, Victor R

2006-01-01

Skeletal muscle appears to be susceptible to chronic and acute excess alcohol intake, giving rise to alcoholic myopathy, a common disease among alcoholics. Fatty acid ethyl esters (FAEE), non-oxidative metabolites of ethanol, have been shown to be toxic to cells in vitro and in vivo. We hypothesized that accumulation of FAEE in skeletal muscle could contribute to the development of alcoholic myopathy. Male wistar rats were treated either with 75 mmol ethanol/kg body weight or saline, in the fed state or starved for 1 or 2 days before administration. Rats were thus divided into the following groups: fed-saline (n = 8); fed-ethanol (n = 8); starved 1 day, saline (n = 8); starved 1 day, ethanol (n = 9); starved 2 days, saline (n = 7); and starved 2 days, ethanol (n = 8). At the end of the incubation, skeletal muscles (abdominal and gastrocnemius), liver, and heart were isolated and processed for FAEE isolation and analysis by gas chromatography-mass spectrometry (GC-MS). Total mass of FAEE in the muscles was much greater than that found in the liver and the heart. In general, the animals that were fasted for 1 day and received ethanol had the highest FAEE levels among the three groups of animals. The major ethyl ester species in all cases were ethyl 16:0, ethyl 18:0, ethyl 18:1 n-9, and ethyl 18:2 n-6. Ethyl 20:4 n-6 and ethyl 22:6 n-3 were also present, except in the fasted 1-day group, where ethyl 22:6 disappeared, though it reappeared in the fasted 2-day group. These findings demonstrate that skeletal muscles contain high levels of FAEE that are synthesized in the body after ethanol exposure. The concentration of FAEE in skeletal muscle in this study was very similar to FAEE concentration in the liver. This differs from previous studies suggesting a low concentration of skeletal muscle FAEE with ethanol exposure.

Evaluation of Tumor Angiogenesis with a Second-Generation US Contrast Medium in a Rat Breast Tumor Model

International Nuclear Information System (INIS)

Ko, Eun Young; Lee, Sang Hoon; Kim, Hak Hee; Kim, Sung Moon; Shin, Myung Jin; Kim, Nam Kug; Gong, Gyung Yub

2008-01-01

Tumor angiogenesis is an important factor for tumor growth, treatment response and prognosis. Noninvasive imaging methods for the evaluation of tumor angiogenesis have been studied, but a method for the quantification of tumor angiogenesis has not been established. This study was designed to evaluate tumor angiogenesis in a rat breast tumor model by the use of a contrast enhanced ultrasound (US) examination with a second-generation US contrast agent. The alkylating agent 19N-ethyl-N-nitrosourea (ENU) was injected into the intraperitoneal cavity of 30-day-old female Sprague-Dawley rats. Three to four months later, breast tumors were detected along the mammary lines of the rats. A total of 17 breast tumors larger than 1 cm in nine rats were evaluated by gray-scale US, color Doppler US and contrast-enhanced US using SonoVue. The results were recorded as digital video images; time-intensity curves and hemodynamic parameters were analyzed. Pathological breast tumor specimens were obtained just after the US examinations. The tumor specimens were stained with hematoxylin and eosin (H and E) and the expression of CD31, an endothelial cell marker, was determined by immunohistochemical staining. We also evaluated the pathological diagnosis of the tumors and the microvessel density (MVD). Spearman's correlation and the Kruskal-Wallis test were used for the analysis. The pathological diagnoses were 11 invasive ductal carcinomas and six benign intraductal epithelial proliferations. The MVD did not correlate with the pathological diagnosis. However, blood volume (BV) showed a statistically significant correlation with MVD (Spearman's correlation, p < 0.05). Contrast-enhanced US using a second-generation US contrast material was useful for the evaluation of tumor angiogenesis of breast tumors in the rat

Novel allelic mutations in murine Serca2 induce differential development of squamous cell tumors

Energy Technology Data Exchange (ETDEWEB)

Toki, Hideaki; Minowa, Osamu; Inoue, Maki; Motegi, Hiromi; Karashima, Yuko; Ikeda, Ami [Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center (BRC), Tsukuba, Ibaraki (Japan); Kaneda, Hideki [Technology and Development Team for Mouse Phenotype Analysis, Riken BRC, Tsukuba, Ibaraki (Japan); Sakuraba, Yoshiyuki [Mutagenesis and Genomics Team, Riken BRC, Tsukuba, Ibaraki (Japan); Saiki, Yuriko [Department of Molecular Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi (Japan); Wakana, Shigeharu [Technology and Development Team for Mouse Phenotype Analysis, Riken BRC, Tsukuba, Ibaraki (Japan); Suzuki, Hiroshi [Department of Biochemistry, Asahikawa Medical University, Asahikawa, Hokkaido (Japan); Gondo, Yoichi [Mutagenesis and Genomics Team, Riken BRC, Tsukuba, Ibaraki (Japan); Shiroishi, Toshihiko [Mammalian Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka (Japan); Noda, Tetsuo, E-mail: tnoda@jfcr.or.jp [Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center (BRC), Tsukuba, Ibaraki (Japan); Department of Cell Biology, Cancer Institute, The Japanese Foundation for Cancer Research, Tokyo (Japan)

2016-08-05

Dominant mutations in the Serca2 gene, which encodes sarco(endo)plasmic reticulum calcium-ATPase, predispose mice to gastrointestinal epithelial carcinoma [1–4] and humans to Darier disease (DD) [14–17]. In this study, we generated mice harboring N-ethyl-N-nitrosourea (ENU)-induced allelic mutations in Serca2: three missense mutations and one nonsense mutation. Mice harboring these Serca2 mutations developed tumors that were categorized as either early onset squamous cell tumors (SCT), with development similar to null-type knockout mice [2,4] (aggressive form; M682, M814), or late onset tumors (mild form; M1049, M1162). Molecular analysis showed no aberration in Serca2 mRNA or protein expression levels in normal esophageal cells of any of the four mutant heterozygotes. There was no loss of heterozygosity at the Serca2 locus in the squamous cell carcinomas in any of the four lines. The effect of each mutation on Ca{sup 2+}-ATPase activity was predicted using atomic-structure models and accumulated mutated protein studies, suggesting that putative complete loss of Serca2 enzymatic activity may lead to early tumor onset, whereas mutations in which Serca2 retains residual enzymatic activity result in late onset. We propose that impaired Serca2 gene product activity has a long-term effect on squamous cell carcinogenesis from onset to the final carcinoma stage through an as-yet unrecognized but common regulatory pathway. -- Highlights: •Novel mutations in murine Serca2 caused early onset or late onset of tumorigenesis. •They also caused higher or lower incidence of Darier Disease phenotype. •3D structure model suggested the former mutations led to severer defect on ATPase. •Driver gene mutations via long-range effect on Ca2+ distributions are suggested.

DNA methylation in the pathophysiology of hyperphenylalaninemia in the PAH(enu2) mouse model of phenylketonuria.

Science.gov (United States)

Dobrowolski, S F; Lyons-Weiler, J; Spridik, K; Vockley, J; Skvorak, K; Biery, A

2016-09-01

Phenylalanine hydroxylase deficient phenylketonuria (PKU) is the paradigm for a treatable inborn error of metabolism where maintaining plasma phenylalanine (Phe) in the therapeutic range relates to improved clinical outcomes. While Phe is the presumed intoxicating analyte causal in neurologic damage, the mechanism(s) of Phe toxicity has remained elusive. Altered DNA methylation is a recognized response associated with exposure to numerous small molecule toxic agents. Paralleling this effect, we hypothesized that chronic Phe over-exposure in the brain would lead to aberrant DNA methylation with secondary influence upon gene regulation that would ultimately contribute to PKU neuropathology. The PAH(enu2) mouse models human PKU with intrinsic hyperphenylalaninemia, abnormal response to Phe challenge, and neurologic deficit. To examine this hypothesis, we assessed DNA methylation patterns in brain tissues using methylated DNA immunoprecipitation and paired end sequencing in adult PAH(enu2) animals maintained under either continuous dietary Phe restriction or chronic hyperphenylalaninemia. Heterozygous PAH(enu2/WT) litter mates served as controls for normal Phe exposure. Extensive repatterning of DNA methylation was observed in brain tissue of hyperphenylalaninemic animals while Phe restricted animals displayed an attenuated pattern of aberrant DNA methylation. Affected gene coding regions displayed aberrant hypermethylation and hypomethylation. Gene body methylation of noncoding RNA genes was observed and among these microRNA genes were prominent. Of particular note, observed only in hyperphenylalaninemic animals, was hypomethylation of miRNA genes within the imprinted Dlk1-Dio3 locus on chromosome 12. Aberrant methylation of microRNA genes influenced their expression which has secondary effects upon the expression of targeted protein coding genes. Differential hypermethylation of gene promoters was exclusive to hyperphenylalaninemic PAH(enu2) animals. Genes with

Synthesis, characterization, and application of novel biodegradable self-assembled 2-(N-phthalimido) ethyl-palmitate nanoparticles for cancer therapy

Science.gov (United States)

Kasoju, Naresh; Bora, Debajeet K.; Bhonde, Ramesh R.; Bora, Utpal

2010-03-01

We report the synthesis of novel biodegradable nanoparticles (NPs) which can kill the cancer cells without any additional drug loading. The NP was a self-assembled form of a phthalimide based conjugate, in which the phthalimide moiety was responsible for the anticancer activity. We describe the synthesis of a novel 2-(N-phthalimido) ethyl palmitate (PHEP-Pal) conjugate and subsequent preparation of NPs by a simple self assembly process. The successful synthesis of conjugate was confirmed by various characterization studies including nuclear magnetic resonance spectroscope, Fourier transform infrared spectroscope, TOF-liquid chromatography mass spectroscope, differential scanning calorimetry, and X-ray diffraction unit. The synthesis, shape, size, and size distribution of PHEP-Pal NPs were determined by transmission electron microscope, atomic force microscope, and dynamic light scattering technique. Finally, cell culture studies using A549 and HeLa cells were done to evaluate the anticancer effect of PHEP-Pal NPs, which demonstrated the potency of these NPs for use in cancer chemotherapy.

Measurement of the Absolute Branching Fraction for Lambda(+)(c) -> Lambda e(+)nu(e)

NARCIS (Netherlands)

Ablikim, M.; Achasov, M.N.; Ai, X.C.; Albayrak, O.; Albrecht, M.; Ambrose, D.J.; Amorose, A.; Haddadi, Z.; Kalantar-Nayestanaki, Nasser; Kavatsyuk, M.; Messchendorp, J.G; Tiemens, M.

2015-01-01

We report the first measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda e(+)nu(e). This measurement is based on 567 pb(-1) of e(+)e(-) annihilation data produced at root s = 4.599 GeV, which is just above the Lambda(+)(c)Lambda(-)(c) threshold. The data were collected with the

(Z-Ethyl 3-(4-chlorophenyl-2-cyano-3-(2,6-difluorobenzamidoacrylate

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Zhang Xiaoyan

2008-12-01

Full Text Available The title compound, C19H13ClF2N2O3, was prepared by the reaction of (Z-ethyl 3-amino-3-(4-chlorophenyl-2-cyanoacrylate and 2,6-difluorobenzoyl chloride. The dihedral angle between the chlorobenzene and fluorobenzene rings is 37.0 (1°. The ethyl group is disordered over two positions [occupancies = 0.52 (2:0.48 (2]. In addition to intramolecular N—H...O and N—H...F hydrogen bonds, the crystal packing shows the molecules to be connected by intermolecular C—H...O and C—H...N hydrogen bonds.

Biodistribution of a 14C- and sup(99m)Tc-labeled N-substituted nitrosourea (CCNU) in an animal tumor model

International Nuclear Information System (INIS)

Castronovo, F.P.; Potsaid, M.S. Jr.; Kopiwoda, S.; Peterson, M.

1980-01-01

One formulation of 14 C labelled and another of sup(99m)Tc labelled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) were administered i.v. to tumour (glioma) bearing rats. The radiopharmacokinetics of 14 C-CCNU were followed up to 24 hours post injection. On a per organ basis the blood, liver, small bowel, kidney cortex and muscle contained most of the activity. Optimum tumour to organ ratios occurred at 4-12 hours. The sup(99m)Tc-CCNU biodistribution was determined at 4 hours and compared to sup(99m)Tc-NaTcO 4 . Tumour capsule to brain (29.5) and to muscle (10.59) ratios suggest sup(99m)Tc-CCNU to be a potential tumour seeking agent. (author)

Fundamental Flotation Behaviors of Chalcopyrite and Galena Using O-Isopropyl-N-Ethyl Thionocarbamate as a Collector

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Yongjie Bu

2018-03-01

Full Text Available Copper and lead are two important and widely used metals in industry. Chalcopyrite (CuFeS2 is associated with galena (PbS in ore, and it has been a research hotspot in separating galena from chalcopyrite by flotation. In this study, the flotation behaviors of chalcopyrite and galena were studied through flotation tests, adsorption measurements, solution chemistry calculation, Fourier transform infrared spectroscopy (FTIR and molecular dynamics (MD simulations. The results show that the floatability of chalcopyrite is better than that of galena in the presence of O-isopropyl-N-ethyl thionocarbamate (IPETC, and the recovery difference between chalcopyrite and galena is about 20% when IPETC is 7 × 10−4 mol/L at pH 9.5, while the floatability difference between the two minerals is significant. Competitive adsorption of OH− and IPETC on mineral surfaces leads to lower floatability of galena than that of chalcopyrite. IPETC is able to remove the hydration layer on mineral surfaces and then adsorb on active sites. The floatability of minerals is enhanced with the increase of their hydrophobicity. This study provides a reference to separate galena from chalcopyrite.

Cross-sensitivity of X-ray-hypersensitive cells derived from LEC strain rats to DNA-damaging agents

International Nuclear Information System (INIS)

Okui, T.; Endoh, D.; Arai, S.; Isogai, E.; Hayashi, M.

1996-01-01

The cross-sensitivity of X-ray-hypersensitive lung fibroblasts from LEC strain (LEC) rats to other DNA-damaging agents was examined. The LEC cells were 2- to 3-fold more sensitive to bleomycin (BLM) that induces DNA double-strand breaks, and to a cross-linking agent, mitomycin C, than the cells from WKAH strain (WKAH) rats, while they were slightly sensitive to alkylating agents, ethyl nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine, but not to UV-irradiation. Although no difference was observed in the initial yields of DNA double-strand breaks induced by BLM between LEC and WKAH cells, the repair process of DNA double-strand breaks was significantly slower in LEC cells than in WKAH cells

Simple preparation of new N-aryl-N-(3-indolmethyl acetamides and their spectroscopic analysis

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José A. Henao

2009-12-01

Full Text Available To prepare new indolic molecules and characterize them by spectroscopic methods. Materials and methods: All reagentswere purchased from Aldrich, commercial grade. The purity of the products and the composition of the reaction mixtures were monitoredby thin layer chromatography over Silufol UV254 0.25 mm-thick chromatoplates. Product isolation and purification were performed bycolumn chromatography (SiO2, using ethyl acetate-petroleum ether mixtures as eluents. Results. The synthesis of new N-aryl-N-(3-indolmethyl acetamides based on first step iminization reaction of indol-3-carbaldehyde is accomplished. The structures of the C-3substituted indoles were confirmed by 1H-NMR and 13C-NMR studies supported by inverse-detected 2D NMR experiments and alsothrough monocrystal X-ray diffraction. Conclusions. An efficient, economic, and fast synthetic route was designed to the construction ofthe N-aryl-N-(3-indolmethyl acetamides, structural analogues of some alkaloids.

Genomic phenotyping by barcode sequencing broadly distinguishes between alkylating agents, oxidizing agents, and non-genotoxic agents, and reveals a role for aromatic amino acids in cellular recovery after quinone exposure.

Science.gov (United States)

Svensson, J Peter; Quirós Pesudo, Laia; McRee, Siobhan K; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D

2013-01-01

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N'-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic 'barcode', were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput 'barcode' sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised.

Improved thermostability and enzyme activity of a recombinant phyA mutant phytase from Aspergillus niger N25 by directed evolution and site-directed mutagenesis.

Science.gov (United States)

Tang, Zizhong; Jin, Weiqiong; Sun, Rong; Liao, Yan; Zhen, Tianrun; Chen, Hui; Wu, Qi; Gou, Lin; Li, Chenlei

2018-01-01

We previously constructed three recombinant phyA mutant strains (PP-NP m -8, PP-NP ep -6A and I44E/T252R-PhyA), showing improved catalytic efficiency or thermostability of Aspergillus niger N25 phytase, by error-prone PCR or site-directed mutagenesis. In this study, directed evolution and site-directed mutagenesis were further applied to improve the modified phytase properties. After one-round error-prone PCR for phytase gene of PP-NP ep -6A, a single transformant, T195L/Q368E/F376Y, was obtained with the significant improvements in catalytic efficiency and thermostability. The phytase gene of T195L/Q368E/F376Y, combined with the previous mutant phytase genes of PP-NP ep -6A, PP-NP m -8 and I44E/T252R-PhyA, was then sequentially modified by DNA shuffling. Three genetically engineered strains with desirable properties were then obtained, namedQ172R, Q172R/K432R andQ368E/K432R. Among them, Q172R/K432R showed the highest thermostability with the longest half-life and the greatest remaining phytase activity after heat treatment, while Q368E/K432R showed the highest catalytic activity. Five substitutions (Q172R, T195L, Q368E, F376Y, K432R) identified from random mutagenesis were added sequentially to the phytase gene of PP-NP ep -6A to investigate how the mutant sites influence the properties of phytase. Characterization and structural analysis demonstrated that these mutations could produce cumulative or synergistic improvements in thermostability or catalytic efficiency of phytase. Copyright © 2017 Elsevier Inc. All rights reserved.

Improvement of DNA transfer frequency and transposon mutagenesis of Erwinia carotovora subsp. betavasculorum.

OpenAIRE

Rella, M; Axelrood, P E; Weinhold, A R; Schroth, M N

1989-01-01

The production of antibiotics and their role in microbial competition under natural conditions can be readily studied by the use of transposon mutants. Several antibiotic-producing strains of Erwinia carotovora subsp. betavasculorum were unable to accept foreign DNA. A plasmid delivery system was developed, using ethyl methanesulfonate mutagenesis, which entailed isolating E. carotovora subsp. betavasculorum mutants able to accept foreign DNA and transfer it to other strains. This enabled tra...

CORRELATION ANALYSIS OF IR, 1 H- AND 13 C-NMR SPECTRAL DATA OF N-ALKYL AND N-CYCLOALKYL CYANOACETAMIDES

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Aleksandar D. Marinković

2011-09-01

Full Text Available Linear free energy relationships (LFER were applied to the IR, 1H- and 13C--NMR spectral data in N-alkyl and N-cycloalkyl cyanoacetamides. N-alkyl and N-cycloalkyl cyanocetamides were synthesized from corresponding amine and ethyl cyanoacetate. A number of substituents were employed for alkyl substitution, and fairly good correlations were obtained, using simple Hammett equation. In N-alkyl and N-cycloalkyl cyanoacetamides substituent cause SCS of N-H hydrogen primarily by steric interaction, polar subtituent effect influences SCS shift of C=O carbon, while steric effect of N-alkyl substituent causes IR stretching frequencies of N-H, C=O and CN group. The conformations of investigated compounds have been studied by the use of semiempirical PM6 method, and together with LFER analysis, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. Negative ρ values for several correlations (reverse substituent effect were found.

Crystal structure of the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate

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Tamara Đorđević

2016-07-01

Full Text Available Both unique Cd atoms in the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate, (C6H11N22[CdBr4], occupy special positions (site symmetry -4. The crystal structure consists of isolated tetrahedral [CdBr4]2− anions which are surrounded by 1-ethyl-3-methylimidazolium cations. The methyl and ethyl side chains of the cations show positional disorder in a 0.590 (11:0.410 (11 ratio. In the crystal, (C6H11N2+ cations display three weak C—H...Br hydrogen-bond interactions through the imidazolium ring H atoms with the Br− ligands of the surrounding complex anions. The alkyl groups of the side chains are not involved in hydrogen bonding.

Uji Fitokimia, Toksisitas dan Aktivitas Antioksidan Fraksi n-heksan dan Etil Asetat terhadap Ekstrak Jahe Merah (Zingiber officinale var. amarum

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Alpina Nora Kaban

2016-11-01

Full Text Available Has conducted research on the phytochemical test, toxicity test and test the antioxidant activity of the fraction of n-hexane and ethyl acetate to extract red ginger (Zingiber officinale amarum var.. The dried leaves weighing 382 grams, was macerated using methanol, filtered and concentrated by rotary evaporator. Then the total extract of red ginger in fractionation with n-hexane and ethyl acetate. Based on the test results of secondary metabolites phytochemical extracts of total red ginger (Zingiber officinale var amarum. Are alkaloids, flavonoids, triterpenoids and phenolic. N-hexane fraction contains alkaloids, flavonoids, steroids, triterpenoids and phenolic. Ethyl acetate fractions contain alkaloids, flavonoids, triterpenoids and phenolic. Toxicity test showed the mortality rate of shrimp larvae Artemia salina Leach using Probit Analysis SAS (Statistical Analysis System to determine the value of 50% Lethal Concentration (LC50, showed that the fraction of n-hexane toxicity with LC50 values of 63.8130 ppm; extracts of total was 71.0121 ppm and ethyl acetate was 3821.89 ppm. Test the antioxidant activity using DPPH free radical reduction in the spectrophotometer and IC50 values obtained on a total extract was 32.19 ppm; n-hexane was fraction 35.63 ppm; and ethyl acetate fraction was 25.69 ppm.

Evaluación de la genotoxicidad de hidrazida málica, N-nitroso dietilamina, y etil metano sulfonato, en núcleos de Tradescantia, por medio de la prueba del cometa

OpenAIRE

Alvarez-Moya, Carlos; Santerre-Lucas, Anne; Zúñiga-González, Guillermo; Torres-Bugarín, Olivia; Padilla-Camberos, Eduardo; Feria-Velasco, Alfredo

2001-01-01

Objective. To assess the genotoxic activity of N-nitroso diethylamine (NDEA), maleic hydrazide (MH), and ethyl methane sulfonate (EMS) using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430). Material and Methods. Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine ...

Identification of radiolytic products from N-nitrosodimethylamine and N-nitrosopyrrolidine by gas chromatography and mass spectrometry

International Nuclear Information System (INIS)

Ahn, H.-J.; Lee, C.-H.; Kim, J.-H.; Han, S.-B.; Jo, Cheorun; Kim, Sung; Byun, M.-W.

2004-01-01

The radiolytic products of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) dissolved in dichloromethane (DCM) were identified after gamma irradiation. The UV spectra of NDMA and NPYR indicated that irradiation reduced the typical peak of NDMA at 258 nm and NPYR at 260 nm.The major radiolytic components identified in irradiated NDMA were ethyl acetate and 2-dimethyl propanol. The irradiated NPYR dissolved in DCM and produced 2-butanone and 2-methyl-6-propyl piperidine as the major radiolytic components. 2-Methyl-6-propyl piperidine was the component detected in the greatest concentration in irradiated NPYR

The carcinogenicity of 1-methyl-3(p-bromophenyl)-1-nitrosourea (Br-MPNU).

Science.gov (United States)

Warzok, R; Martin, J; Mendel, J; Thust, R; Schwarz, H

1983-01-01

In long-term experiments with Hooded rats the carcinogenic potential of 1-methyl-3(p-bromophenyl)-1-nitrosourea (Br-MPNU) could be demonstrated for the first time. Br-MPNU is formed also endogenously after combined administration of 1-methyl-3(p-bromophenyl)-urea (Br-MPU) and sodium nitrite. After repeated intragastric administration of 0.33 mmol Br-MPU and 0.73 mmol NaNO2 per kg b.w. papillomas and carcinomas of the forestomach developed in 83%. After repeated administration of 0.28 mmol Br-MPNU per kg b.w. these neoplasms were observed in 88%. The comparison of results obtained in similar experiments with 1-methyl-3-phenyl-1-nitrosourea shows that bromine substitution led to a reduction of the carcinogenic activity. The present paper is part of a complex program studying the interrelationships between structure, physico-chemical properties, mutagenicity and carcinogenicity of nitrosoureas.

Involvement of Pseudomonas putida RpoN sigma factor in regulation of various metabolic functions.

OpenAIRE

Köhler, T; Harayama, S; Ramos, J L; Timmis, K N

1989-01-01

The RpoN protein was originally identified in Escherichia coli as a sigma (sigma) factor essential for the expression of nitrogen regulons. In the present study we cloned the Pseudomonas putida rpoN gene and identified its gene product as a protein with an apparent molecular weight of 78,000. A mutant rpoN gene was constructed by in vitro insertion mutagenesis with a kanamycin cassette. A P. putida rpoN mutant was then isolated by replacement of the intact chromosomal rpoN gene by the mutant ...

Analysis of the interaction between two nitrosourea compounds and X-irradiation in rat brain tumour cells

Energy Technology Data Exchange (ETDEWEB)

Leenhouts, H P; Chadwick, K H [Association Euratom-ITAL, Wageningen (Netherlands); Deen, D F [California Univ., San Francisco (USA). Dept. of Neurology

1980-02-01

Experimental measurements have shown that both BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) and CCNU (1-(2-choroethyl)-3-cyclohexyl-1-nitrosourea) are toxic in rat 9L brain tumour cells and also sensitize these cells to the action of ionizing radiation. The interaction of BCNU and CCNU with radiation has been interpreted using a recently developed extension of the molecular theory of cell survival. The experimental results are shown to be compatible with the mathematical equations predicted by the model and the analysis indicates that the sensitizing effect is caused by a synergistic interaction between sublethal damage caused by the nitrosourea compound and the radiation at the molecular level. The analysis of the dependence of the interaction on the time between nitrosourea treatment and radiation indicates that the optimal interaction occurs with a 5 hour interval.

Effective lethal mutagenesis of influenza virus by three nucleoside analogs.

Science.gov (United States)

Pauly, Matthew D; Lauring, Adam S

2015-04-01

Lethal mutagenesis is a broad-spectrum antiviral strategy that exploits the high mutation rate and low mutational tolerance of many RNA viruses. This approach uses mutagenic drugs to increase viral mutation rates and burden viral populations with mutations that reduce the number of infectious progeny. We investigated the effectiveness of lethal mutagenesis as a strategy against influenza virus using three nucleoside analogs, ribavirin, 5-azacytidine, and 5-fluorouracil. All three drugs were active against a panel of seasonal H3N2 and laboratory-adapted H1N1 strains. We found that each drug increased the frequency of mutations in influenza virus populations and decreased the virus' specific infectivity, indicating a mutagenic mode of action. We were able to drive viral populations to extinction by passaging influenza virus in the presence of each drug, indicating that complete lethal mutagenesis of influenza virus populations can be achieved when a sufficient mutational burden is applied. Population-wide resistance to these mutagenic agents did not arise after serial passage of influenza virus populations in sublethal concentrations of drug. Sequencing of these drug-passaged viral populations revealed genome-wide accumulation of mutations at low frequency. The replicative capacity of drug-passaged populations was reduced at higher multiplicities of infection, suggesting the presence of defective interfering particles and a possible barrier to the evolution of resistance. Together, our data suggest that lethal mutagenesis may be a particularly effective therapeutic approach with a high genetic barrier to resistance for influenza virus. Influenza virus is an RNA virus that causes significant morbidity and mortality during annual epidemics. Novel therapies for RNA viruses are needed due to the ease with which these viruses evolve resistance to existing therapeutics. Lethal mutagenesis is a broad-spectrum strategy that exploits the high mutation rate and the low

Search for the weak decays J/psi -> D-s(()*()-) e(+)nu(e) + c.c.

NARCIS (Netherlands)

Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Ferroli, R. Baldini; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, H. Y.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Cheng, H. P.; Chu, X. K.; Chu, Y. P.; Cibinetto, G.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Duan, P. F.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Fava, L.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fu, C. D.; Gao, Q.; Gao, Y.; Garzia, I.; Goetzen, K.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, T.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S; Han, Y. L.; Harris, F. A.; He, K. L.; He, Z. Y.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. M.; Huang, G. S.; Huang, H. P.; Huang, J. S.; Huang, X. T.; Huang, Y.; Hussain, T.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. L.; Jiang, L. W.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuehn, W.; Kupsc, A.; Lai, W.; Lange, J. S.; Lara, M.; Larin, P.; Li, C. H.; Li, Cheng; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, P. R.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. M.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, R. Q.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lv, M.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, Q. M.; Ma, S.; Ma, T.; Ma, X. N.; Ma, X. Y.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Moeini, H.; Morales, C. Morales; Moriya, K.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Pu, Y. N.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Y.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ren, H. L.; Ripka, M.; Rong, G.; Ruan, X. D.; Santoro, V.; Sarantsev, A.; Savrie, M.; Schoenning, K.; Schumann, S.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Spruck, B.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Toth, D.; Ullrich, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q. J.; Wang, S. G.; Wang, W.; Wang, X. F.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Wei, D. H.; Wei, J. B.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, Z.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. X.; Yang, L.; Yang, Y.; Yang, Y. X.; Ye, H.; Ye, M.; Ye, M. H.; Yin, J. H.; Yu, B. X.; Yu, C. X.; Yu, H. W.; Yu, J. S.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. H.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, Li; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.

2014-01-01

Using a sample of 2.25 x 10(8) J/psi events collected with the BESIII detector at the BEPCII collider, we search for the J/psi semileptonic weak decay J/psi -> D-s(-) e(+)nu(e) +c.c. with a much higher sensitivity than previous searches. We also perform the first search for J/psi -> D-s(*-) e(+)

Hydroxide as general base in the saponification of ethyl acetate.

Science.gov (United States)

Mata-Segreda, Julio F

2002-03-13

The second-order rate constant for the saponification of ethyl acetate at 30.0 degrees C in H(2)O/D(2)O mixtures of deuterium atom fraction n (a proton inventory experiment) obeys the relation k(2)(n) = 0.122 s(-1) M(-1) (1 - n + 1.2n) (1 - n + 0.48n)/(1 - n + 1.4n) (1 - n + 0.68n)(3). This result is interpreted as a process where formation of the tetrahedral intermediate is the rate-determining step and the transition-state complex is formed via nucleophilic interaction of a water molecule with general-base assistance from hydroxide ion, opposite to the direct nucleophilic collision commonly accepted. This mechanistic picture agrees with previous heavy-atom kinetic isotope effect data of Marlier on the alkaline hydrolysis of methyl formate.

2,6-Dithiopurine, a nucleophilic scavenger, protects against mutagenesis in mouse skin treated in vivo with 2-(chloroethyl) ethyl sulfide, a mustard gas analog

Energy Technology Data Exchange (ETDEWEB)

Boulware, Stephen [Division of Pharmacy and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723 (United States); Fields, Tammy; McIvor, Elizabeth; Powell, K. Leslie; Abel, Erika L. [Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957 (United States); Vasquez, Karen M. [Division of Pharmacy and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723 (United States); MacLeod, Michael C., E-mail: mcmacleod@mdanderson.org [Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957 (United States)

2012-09-01

Sulfur mustard [bis(2-chloroethyl)sulfide, SM] is a well-known DNA-damaging agent that has been used in chemical warfare since World War I, and is a weapon that could potentially be used in a terrorist attack on a civilian population. Dermal exposure to high concentrations of SM produces severe, long-lasting burns. Topical exposure to high concentrations of 2-(chloroethyl) ethyl sulfide (CEES), a monofunctional analog of SM, also produces severe skin lesions in mice. Utilizing a genetically engineered mouse strain, Big Blue, that allows measurement of mutation frequencies in mouse tissues, we now show that topical treatment with much lower concentrations of CEES induces significant dose- and time-dependent increases in mutation frequency in mouse skin; the mutagenic exposures produce minimal toxicity as determined by standard histopathology and immunohistochemical analysis for cytokeratin 6 and the DNA-damage induced phosphorylation of histone H2AX (γ-H2AX). We attempted to develop a therapeutic that would inhibit the CEES-induced increase in mutation frequency in the skin. We observe that multi-dose, topical treatment with 2,6-dithiopurine (DTP), a known chemical scavenger of CEES, beginning 1 h post-exposure to CEES, completely abolishes the CEES-induced increase in mutation frequency. These findings suggest the possibility that DTP, previously shown to be non-toxic in mice, may be useful as a therapeutic agent in accidental or malicious human exposures to SM. -- Highlights: ► 200 mM 2-(chloroethyl) ethyl sulfide (CEES) induces mutations in mouse skin. ► This dose of CEES is not overtly toxic, as assayed by histopathology. ► 2,6-Dithiopurine (DTP), applied after CEES-treatment, abolishes CEES-mutagenesis. ► This supports the idea that sulfur mustards exhibit long biological half-lives.

2,6-Dithiopurine, a nucleophilic scavenger, protects against mutagenesis in mouse skin treated in vivo with 2-(chloroethyl) ethyl sulfide, a mustard gas analog

International Nuclear Information System (INIS)

Boulware, Stephen; Fields, Tammy; McIvor, Elizabeth; Powell, K. Leslie; Abel, Erika L.; Vasquez, Karen M.; MacLeod, Michael C.

2012-01-01

Sulfur mustard [bis(2-chloroethyl)sulfide, SM] is a well-known DNA-damaging agent that has been used in chemical warfare since World War I, and is a weapon that could potentially be used in a terrorist attack on a civilian population. Dermal exposure to high concentrations of SM produces severe, long-lasting burns. Topical exposure to high concentrations of 2-(chloroethyl) ethyl sulfide (CEES), a monofunctional analog of SM, also produces severe skin lesions in mice. Utilizing a genetically engineered mouse strain, Big Blue, that allows measurement of mutation frequencies in mouse tissues, we now show that topical treatment with much lower concentrations of CEES induces significant dose- and time-dependent increases in mutation frequency in mouse skin; the mutagenic exposures produce minimal toxicity as determined by standard histopathology and immunohistochemical analysis for cytokeratin 6 and the DNA-damage induced phosphorylation of histone H2AX (γ-H2AX). We attempted to develop a therapeutic that would inhibit the CEES-induced increase in mutation frequency in the skin. We observe that multi-dose, topical treatment with 2,6-dithiopurine (DTP), a known chemical scavenger of CEES, beginning 1 h post-exposure to CEES, completely abolishes the CEES-induced increase in mutation frequency. These findings suggest the possibility that DTP, previously shown to be non-toxic in mice, may be useful as a therapeutic agent in accidental or malicious human exposures to SM. -- Highlights: ► 200 mM 2-(chloroethyl) ethyl sulfide (CEES) induces mutations in mouse skin. ► This dose of CEES is not overtly toxic, as assayed by histopathology. ► 2,6-Dithiopurine (DTP), applied after CEES-treatment, abolishes CEES-mutagenesis. ► This supports the idea that sulfur mustards exhibit long biological half-lives.

Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization and antimalarial properties.

Science.gov (United States)

Ekengard, Erik; Kumar, Kamlesh; Fogeron, Thibault; de Kock, Carmen; Smith, Peter J; Haukka, Matti; Monari, Magda; Nordlander, Ebbe

2016-03-07

The synthesis and characterization of twenty new pentamethylcyclopentadienyl-rhodium and iridium complexes containing N^N and N^O-chelating chloroquine analogue ligands are described. The in vitro antimalarial activity of the new ligands as well as the complexes was evaluated against the chloroquine sensitive (CQS) NF54 and the chloroquine resistant (CQR) Dd2 strains of Plasmodium falciparum. The antimalarial activity was found to be good to moderate; although all complexes are less active than artesunate, some of the ligands and complexes showed better activity than chloroquine (CQ). In particular, rhodium complexes were found to be considerably more active than iridium complexes against the CQS NF54 strain. Salicylaldimine Schiff base ligands having electron-withdrawing groups (F, Cl, Br, I and NO2) in para position of the salicyl moiety and their rhodium complexes showed good antiplasmodial activity against both the CQS-NF54 and the CQR-Dd2 strains. The crystal structures of (η(5)-pentamethylcyclopentadienyl){N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)} chlororhodium(III) chloride and (η(5)-pentamethylcyclopentadienyl){(4-chloro-2-(((2-((7-chloroquinolin-4-yl)amino)ethyl)imino)methyl)phenolate)}chlororhodium(III) chloride are reported. The crystallization of the amino-pyridyl complex (η(5)-pentamethylcyclopentadienyl){(N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)}chloroiridium(III) chloride in acetone resulted in the formation of the imino-pyridyl derivative (η(5)-pentamethylcyclopentadienyl){(N1-(7-chloroquinolin-4-yl)-N2-(pyridin-2-ylmethylene)ethane-1,2-diamine)}chloroiridium(III) chloride, the crystal structure of which is also reported.

A splice site mutation in laminin-α2 results in a severe muscular dystrophy and growth abnormalities in zebrafish.

Directory of Open Access Journals (Sweden)

Vandana A Gupta

Full Text Available Congenital muscular dystrophy (CMD is a clinically and genetically heterogeneous group of inherited muscle disorders. In patients, muscle weakness is usually present at or shortly after birth and is progressive in nature. Merosin deficient congenital muscular dystrophy (MDC1A is a form of CMD caused by a defect in the laminin-α2 gene (LAMA2. Laminin-α2 is an extracellular matrix protein that interacts with the dystrophin-dystroglycan (DGC complex in membranes providing stability to muscle fibers. In an N-ethyl-N-nitrosourea mutagenesis screen to develop zebrafish models of neuromuscular diseases, we identified a mutant fish that exhibits severe muscular dystrophy early in development. Genetic mapping identified a splice site mutation in the lama2 gene. This splice site is highly conserved in humans and this mutation results in mis-splicing of RNA and a loss of protein function. Homozygous lama2 mutant zebrafish, designated lama2(cl501/cl501, exhibited reduced motor function and progressive degeneration of skeletal muscles and died at 8-15 days post fertilization. The skeletal muscles exhibited damaged myosepta and detachment of myofibers in the affected fish. Laminin-α2 deficiency also resulted in growth defects in the brain and eye of the mutant fish. This laminin-α2 deficient mutant fish represents a novel disease model to develop therapies for modulating splicing defects in congenital muscular dystrophies and to restore the muscle function in human patients with CMD.

Real-time resolution of point mutations that cause phenovariance in mice

Science.gov (United States)

Wang, Tao; Zhan, Xiaowei; Bu, Chun-Hui; Lyon, Stephen; Pratt, David; Hildebrand, Sara; Choi, Jin Huk; Zhang, Zhao; Zeng, Ming; Wang, Kuan-wen; Turer, Emre; Chen, Zhe; Zhang, Duanwu; Yue, Tao; Wang, Ying; Shi, Hexin; Wang, Jianhui; Sun, Lei; SoRelle, Jeff; McAlpine, William; Hutchins, Noelle; Zhan, Xiaoming; Fina, Maggy; Gobert, Rochelle; Quan, Jiexia; Kreutzer, McKensie; Arnett, Stephanie; Hawkins, Kimberly; Leach, Ashley; Tate, Christopher; Daniel, Chad; Reyna, Carlos; Prince, Lauren; Davis, Sheila; Purrington, Joel; Bearden, Rick; Weatherly, Jennifer; White, Danielle; Russell, Jamie; Sun, Qihua; Tang, Miao; Li, Xiaohong; Scott, Lindsay; Moresco, Eva Marie Y.; McInerney, Gerald M.; Karlsson Hedestam, Gunilla B.; Xie, Yang; Beutler, Bruce

2015-01-01

With the wide availability of massively parallel sequencing technologies, genetic mapping has become the rate limiting step in mammalian forward genetics. Here we introduce a method for real-time identification of N-ethyl-N-nitrosourea-induced mutations that cause phenotypes in mice. All mutations are identified by whole exome G1 progenitor sequencing and their zygosity is established in G2/G3 mice before phenotypic assessment. Quantitative and qualitative traits, including lethal effects, in single or multiple combined pedigrees are then analyzed with Linkage Analyzer, a software program that detects significant linkage between individual mutations and aberrant phenotypic scores and presents processed data as Manhattan plots. As multiple alleles of genes are acquired through mutagenesis, pooled “superpedigrees” are created to analyze the effects. Our method is distinguished from conventional forward genetic methods because it permits (1) unbiased declaration of mappable phenotypes, including those that are incompletely penetrant (2), automated identification of causative mutations concurrent with phenotypic screening, without the need to outcross mutant mice to another strain and backcross them, and (3) exclusion of genes not involved in phenotypes of interest. We validated our approach and Linkage Analyzer for the identification of 47 mutations in 45 previously known genes causative for adaptive immune phenotypes; our analysis also implicated 474 genes not previously associated with immune function. The method described here permits forward genetic analysis in mice, limited only by the rates of mutant production and screening. PMID:25605905

In vitro evaluation of antioxidant activity of Anisopus mannii N.E. Br ...

African Journals Online (AJOL)

The total phenolic content was higher in the ethyl acetate fraction (59.60 mg/g gallic acid equivalent GAE) than in the nbutanol fraction (56.40 mg/g GAE) and crude methanol extract (53.20 mg/g GAE). The reducing power of n-butanol fraction was 0.112 nm higher than those of ethyl acetate fraction (0.110 nm) and crude ...

Differential genotoxicity of ethyl methanesulphonate, N-ethyl-N-nitrosourea and maleic hydrazide in tobacco seedlings based on data of the Comet assay and two recombination assays

Czech Academy of Sciences Publication Activity Database

Gichner, Tomáš

2003-01-01

Roč. 538, - (2003), s. 171-179 ISSN 1383-5718 R&D Projects: GA ČR GA521/02/0400; GA MŠk LN00B030 Institutional research plan: CEZ:AV0Z5038910 Keywords : DNA damage * Nicotiana tabacum * Single cell gel electrophoresis (SCGE) Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.748, year: 2003

Screening for Neuraminidase Inhibitor Resistance Markers among Avian Influenza Viruses of the N4, N5, N6, and N8 Neuraminidase Subtypes.

Science.gov (United States)

Choi, Won-Suk; Jeong, Ju Hwan; Kwon, Jin Jung; Ahn, Su Jeong; Lloren, Khristine Kaith S; Kwon, Hyeok-Il; Chae, Hee Bok; Hwang, Jungwon; Kim, Myung Hee; Kim, Chul-Joong; Webby, Richard J; Govorkova, Elena A; Choi, Young Ki; Baek, Yun Hee; Song, Min-Suk

2018-01-01

Several subtypes of avian influenza viruses (AIVs) are emerging as novel human pathogens, and the frequency of related infections has increased in recent years. Although neuraminidase (NA) inhibitors (NAIs) are the only class of antiviral drugs available for therapeutic intervention for AIV-infected patients, studies on NAI resistance among AIVs have been limited, and markers of resistance are poorly understood. Previously, we identified unique NAI resistance substitutions in AIVs of the N3, N7, and N9 NA subtypes. Here, we report profiles of NA substitutions that confer NAI resistance in AIVs of the N4, N5, N6, and N8 NA subtypes using gene-fragmented random mutagenesis. We generated libraries of mutant influenza viruses using reverse genetics (RG) and selected resistant variants in the presence of the NAIs oseltamivir carboxylate and zanamivir in MDCK cells. In addition, two substitutions, H274Y and R292K (N2 numbering), were introduced into each NA gene for comparison. We identified 37 amino acid substitutions within the NA gene, 16 of which (4 in N4, 4 in N5, 4 in N6, and 4 in N8) conferred resistance to NAIs (oseltamivir carboxylate, zanamivir, or peramivir) as determined using a fluorescence-based NA inhibition assay. Substitutions conferring NAI resistance were mainly categorized as either novel NA subtype specific (G/N147V/I, A246V, and I427L) or previously reported in other subtypes (E119A/D/V, Q136K, E276D, R292K, and R371K). Our results demonstrate that each NA subtype possesses unique NAI resistance markers, and knowledge of these substitutions in AIVs is important in facilitating antiviral susceptibility monitoring of NAI resistance in AIVs. IMPORTANCE The frequency of human infections with avian influenza viruses (AIVs) has increased in recent years. Despite the availability of vaccines, neuraminidase inhibitors (NAIs), as the only available class of drugs for AIVs in humans, have been constantly used for treatment, leading to the inevitable emergence

An analysis of the interaction between two nitrosourea compounds and X-irradiation in rat brain tumour cells

International Nuclear Information System (INIS)

Leenhouts, H.P.; Chadwick, K.H.; Deen, D.F.

1980-01-01

Experimental measurements have shown that both BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea] and CCNU [1-(2-choroethyl)-3-cyclohexyl-1-nitrosourea] are toxic in rat 9L brain tumour cells and also sensitize these cells to the action of ionizing radiation. The interaction of BCNU and CCNU with radiation has been interpreted using a recently developed extension of the molecular theory of cell survival. The experimental results are shown to be compatible with the mathematical equations predicted by the model and the analysis indicates that the sensitizing effect is caused by a synergistic interaction between sublethal damage caused by the nitrosourea compound and the radiation at the molecular level. The analysis of the dependence of the interaction on the time between nitrosourea treatment and radiation indicates that the optimal interaction occurs with a 5 hour interval. (Author)

Crystal structure of poly[N,N-diethyl-2-hy-droxy-ethan-1-aminium [μ3-cyanido-κ(3) C:C:N-di-μ-cyanido-κ(4) C:N-dicuprate(I)

Science.gov (United States)

Corfield, Peter W R; Cleary, Emma; Michalski, Joseph F

2016-07-01

In the title compound, {(C6H16NO)[Cu2(CN)3]} n , the cyanide groups link the Cu(I) atoms into an open three-dimensional anionic network, with the mol-ecular formula Cu2(CN)3 (-). One Cu(I) atom is tetra-hedrally bound to four CN groups, and the other Cu(I) atom is bonded to three CN groups in an approximate trigonal-planar coordination. The tetra-hedrally coordinated Cu(I) atoms are linked into centrosymmetric dimers by the C atoms of two end-on bridging CN groups which bring the Cu(I) atoms into close contact at 2.5171 (7) Å. Two of the cyanide groups bonded to the Cu(I) atoms with trigonal-planar surrounding link the dimeric units into columns along the a axis, and the third links the columns together to form the network. The N,N-di-ethyl-ethano-lamine mol-ecules used in the synthesis have become protonated at the N atoms and are situated in cavities in the network, providing charge neutrality, with no covalent inter-actions between the cations and the anionic network.

In the search for new anticancer drugs XII. Synthesis and biological evaluation of spin labeled nitrosoureas.

Science.gov (United States)

Sosnovsky, G; Li, S W

1985-04-15

The spin labeled nitrosourea 1-(2-chloroethyl)-3-(1-oxyl-2,2,6,6- tetramethyl-piperidinyl)-1-nitrosourea (SLCNU, 4) and its analogues 5-7 were synthesized either by a regio-selective method or by a conventional route via the nitrosation of the spin labeled intermediates (11a-e). Nitrosation of the ureas 11a-e with dinitrogen tetraoxide resulted in better yields than those obtained with sodium nitrite. The nitrosoureas 4-8 were tested for their anticancer activity against the lymphocytic leukemia P388 in mice. Thus, either at the equal molar dose or at the dose of equal toxicity level, the SLCNU (4) was found to be more active than the clinically used CCNU (1). Unlike CCNU (1) whose LD50 is 56 mg/kg, the SLCNU (4) possesses a low toxicity (LD50 123 mg/kg). Therefore, SLCNU (4) is a promising new entry into the nitrosourea class of anticancer drugs.

Distinct hydrophobic “patches” in the N- and C-tails of beta-catenin contribute to nuclear transport

Energy Technology Data Exchange (ETDEWEB)

Sharma, Manisha; Jamieson, Cara; Lui, Christina [Center for Cancer Research, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145 (Australia); Henderson, Beric R., E-mail: beric.henderson@sydney.edu.au [Center for Cancer Research, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145 (Australia)

2016-11-01

β-catenin is a key mediator of Wnt signaling and its deregulated nuclear accumulation can drive cancer progression. While the central armadillo (Arm) repeats of β-catenin stimulate nuclear entry, the N- and C-terminal “tail” sequences are thought to regulate turnover and transactivation. We show here that the N- and C-tails are also potent transport sequences. The unstructured tails of β-catenin, when individually fused to a GFP-reporter, could enter and exit the nucleus rapidly in live cells. Proximity ligation assays and pull-down assays identified a weak interaction between the tail sequences and the FG-repeats of nucleoporins, consistent with a possible direct translocation of β-catenin through the nuclear pore complex. Extensive alanine mutagenesis of the tail sequences revealed that nuclear translocation of β-catenin was dependent on specific uniformly distributed patches of hydrophobic residues, whereas the mutagenesis of acidic amino acids had no effect. Moreover, the mutation of hydrophobic patches within the N-tail and C-tail of full length β-catenin reduced nuclear transport rate and diminished its ability to activate transcription. We propose that the tail sequences can contribute to β-catenin transport and suggest a possible similar role for hydrophobic unstructured regions in other proteins. - Highlights: • We show that the N- and C-tails of beta-catenin possess nuclear transport activity. • Nuclear transport of the N- or C-tails requires specific hydrophobic amino acids. • Mutagenesis of the N-terminus diminished nuclear entry of full-length beta-catenin. • We propose the N-tail contributes to beta-catenin nuclear entry and transactivation.

Thermal Studies of Zn(II, Cd(II and Hg(II Complexes of Some N-Alkyl-N-Phenyl-Dithiocarbamates

Directory of Open Access Journals (Sweden)

Peter A. Ajibade

2012-07-01

Full Text Available The thermal decomposition of Zn(II, Cd(II and Hg(II complexes of N-ethyl-N-phenyl and N-butyl-N-phenyl dithiocarbamates have been studied using thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The products of the decomposition, at two different temperatures, were further characterized by scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDX. The results show that while the zinc and cadmium complexes undergo decomposition to form metal sulphides, and further undergo oxidation forming metal oxides as final products, the mercury complexes gave unstable volatiles as the final product.

Prediction of anticancer activity of aliphatic nitrosoureas using ...

African Journals Online (AJOL)

Design and development of new anticancer drugs with low toxicity is a very challenging task and computer aided methods are being increasingly used to solve this problem. In this study, we investigated the anticancer activity of aliphatic nitrosoureas using quantum chemical quantitative structure activity relation (QSAR) ...

Synthesis of specifically 15N- and 13C-labeled antitumor (2-Haloethyl)nitrosoureas. The study of their conformations in solution by nitrogen-15 and carbon-13 nuclear magnetic resonance and evidence for stereoelectronic control in their aqueous decomposition

International Nuclear Information System (INIS)

Lown, J.W.; Chauhan, S.M.S.

1981-01-01

The synthesis of certain specifically 15 N, 13 C, and 2 H isotope labeled 1-(2-chloroethyl)-3-alkyl-1-nitrosoureas (CENUs) is described. Spectroscopic examination of CENUs and their isotope-labeled counterparts by 1 H, 15 N, and 13 C NMR and infrared spectra indicates that they adopt preferred conformations in nonpolar aprotic solvents in which the NO group is aligned toward the 2-chloroethyl group. The result is in accord with the conformation of MeCCNU in the crystalline state derived from X-ray diffraction. The chemical shifts and coupling constants in the CENUs change with both solvent polarity and basicity. In aqueous phosphate buffer there is evidence for the formation of a tetrahedral intermediate, the conformation of which alters according to the reaction conditions and ultimately controls the formation of the aqueous decomposition products of CENUs. This is revealed most clearly by 13 C NMR of carbonyl- 13 C- and nitroso- 15 N-labeled BCNU and CCNU where two distinct 15 N-coupled 13 C doublets with different chemical shifts are observed. The rate of conformational change is comparable with the rate of decomposition of CENUs (via the second conformer) and may therefore represent the critical initial step of the latter process in vivo. The intermediacy of the postulated tetrahedral intermediates for CENUs is supported by observed 18 O exchange into the carbonyl group in 18 O-enriched water. Consideration of the conformations of the intermediates and of the alignment of the heteroatom lone pairs provides a satisfactory interpretation of the reactions of CENUs in aqueous solution as well as their pH dependence in terms of strict steroelectronic control and accounts for the formation of the observed products

Genomic phenotyping by barcode sequencing broadly distinguishes between alkylating agents, oxidizing agents, and non-genotoxic agents, and reveals a role for aromatic amino acids in cellular recovery after quinone exposure.

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J Peter Svensson

Full Text Available Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS, N-Methyl-N-nitrosourea (MNU, N,N'-bis(2-chloroethyl-N-nitroso-urea (BCNU, N-ethylnitrosourea (ENU, two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN, benzene-1,4-diol (hydroquinone, HYQ, and two non-genotoxic (methyl carbamate (MC and dimethyl sulfoxide (DMSO compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic 'barcode', were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput 'barcode' sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised.

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses.

Science.gov (United States)

Song, Min-Suk; Marathe, Bindumadhav M; Kumar, Gyanendra; Wong, Sook-San; Rubrum, Adam; Zanin, Mark; Choi, Young-Ki; Webster, Robert G; Govorkova, Elena A; Webby, Richard J

2015-11-01

Human infections with avian influenza viruses are a serious public health concern. The neuraminidase (NA) inhibitors (NAIs) are the frontline anti-influenza drugs and are the major option for treatment of newly emerging influenza. Therefore, it is essential to identify the molecular markers of NAI resistance among specific NA subtypes of avian influenza viruses to help guide clinical management. NAI-resistant substitutions in NA subtypes other than N1 and N2 have been poorly studied. Here, we identified NA amino acid substitutions associated with NAI resistance among influenza viruses of N3, N7, and N9 subtypes which have been associated with zoonotic transmission. We applied random mutagenesis and generated recombinant influenza viruses carrying single or double NA substitution(s) with seven internal genes from A/Puerto Rico/8/1934 (H1N1) virus. In a fluorescence-based NA inhibition assay, we identified three categories of NA substitutions associated with reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir): (i) novel subtype-specific substitutions in or near the enzyme catalytic site (R152W, A246T, and D293N, N2 numbering), (ii) subtype-independent substitutions (E119G/V and/or D and R292K), and (iii) substitutions previously reported in other subtypes (Q136K, I222M, and E276D). Our data show that although some markers of resistance are present across NA subtypes, other subtype-specific markers can only be determined empirically. The number of humans infected with avian influenza viruses is increasing, raising concerns of the emergence of avian influenza viruses resistant to neuraminidase (NA) inhibitors (NAIs). Since most studies have focused on NAI-resistance in human influenza viruses, we investigated the molecular changes in NA that could confer NAI resistance in avian viruses grown in immortalized monolayer cells, especially those of the N3, N7, and N9 subtypes, which have caused human infections. We identified not only numerous NAI

Genome-wide allelotyping of a new in vitro model system reveals early events in breast cancer progression.

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Li, Zheng; Meng, Zhen Hang; Sayeed, Aejaz; Shalaby, Refaat; Ljung, Britt-Marie; Dairkee, Shanaz H

2002-10-15

Toward the goal of identifying early genetic losses, which mediate the release of human breast epithelium from replicative suppression leading to cellular immortalization, we have used a newly developed in vitro model system. This system consists of epithelial cultures derived from noncancerous breast tissue, treated with the chemical carcinogen N-ethyl-N-nitrosourea, and continuously passaged to yield cell populations culminating in the immortal phenotype. Genome-wide allelotyping of early passage N-ethyl-N-nitrosourea-exposed cell populations revealed aberrations at >10% (18 of 169) loci examined. Allelic losses encompassing chromosomes 6q24-6q27, implicating immortalization-associated candidate genes, hZAC and SEN6, occurred in two independently derived cell lines before the Hayflick limit. Additional LOH sites were present in one cell line at 3p11-3p26, 11p15, and 20p12-13. Allelic losses reported in this cell line preceded detectable levels of telomerase activity and the occurrence of p53-related aberrations. Information gained from the search for early immortalization-associated genetic deletions in cultured cells was applied in a novel approach toward the analysis of morphologically normal terminal ductal lobular units microdissected from 20 cases of ductal carcinoma in situ. Notably, clonal allelic losses at chromosome 3p24 and 6q24 were an early occurrence in adjoining terminal ductal lobular units of a proportion of primary tumors, which displayed loss of heterozygosity (3 of 11 and 3 of 6, respectively). The biological insights provided by the new model system reported here strongly suggest that early allelic losses delineated in immortalized cultures and validated in vivo could serve as surrogate endpoints to assist in the identification and intervention of high-risk benign breast tissue, which sustains the potential for continuous proliferation.

Synthesis, in vitro pharmacologic characterization, and preclinical evaluation of N-[2-(1'-piperidinyl)ethyl]-3-[125I]iodo-4-methoxybenzamide (P[125I]MBA) for imaging breast cancer

International Nuclear Information System (INIS)

John, Christy S.; Bowen, Wayne D.; Fisher, Susan J.; Lim, Benjamin B.; Geyer, Brian C.; Vilner, Bertold J.; Wahl, Richard L.

1999-01-01

The goal of this study was to investigate the potential use of a radioiodinated benzamide, N-[2-(1'-piperidinyl)ethyl]-3-iodo[ 125 I]-4-methoxybenzamide (P[ 125 I]MBA), a sigma receptor binding radioligand for imaging breast cancer. The chemical and radiochemical syntheses of PIMBA are described. The pharmacological evaluation of PIMBA was carried out for sigma-1 and sigma-2 receptor sites. The in vivo pharmacokinetics of the radioiodinated benzamide were determined in rats and comparison of P[ 125 I]MBA with Tc-99m sestamibi were made in a rat mammary tumor model. Sigma-1 affinity (K i ) for PIMBA in guinea pig brain membranes using [ 3 H](+)pentazocine was found to be 11.82±0.68 nM, whereas sigma-2 affinity in rat liver using [ 3 H]DTG (1,3-o-di-tolylguanidine) was 206±11 nM. Sites in guinea pig brain membranes labeled by P[ 125 I]MBA showed high affinity for haloperidol, (+)-pentazocine, BD1008, and PIMBA ( K i =4.87±1.49,8.81±1.97,0.057±0.005,46.9±1.8 nM, respectively). Competition binding studies were carried out in human ductal breast carcinoma cells (T47D). A dose-dependent inhibition of specific binding was observed with several sigma ligands. K i values for the inhibition of P[ 125 I]MBA binding in T47D cells for haloperidol, N-[2-(1'-piperidinyl)]ethyl]4-iodobenzamide (IPAB), N-(N-benzylpiperidin-4-yl)-4-iodobenzamide (4-IBP), and PIMBA were found to be 1.30±0.07, 13±1.5, 5.19±2.3, 1.06±0.5 nM, respectively. The in vitro binding data in guinea pig brain membranes and breast cancer cells confirmed binding to sigma sites. The saturation binding of P[ 125 I]MBA in T47D cells as studied by Scatchard analysis showed saturable binding, with a K d =94±7 nM and a B max =2035±305 fmol/mg of proteins. Biodistribution studies in Sprague-Dawley rats showed a rapid clearance of P[ 125 I]MBA from the normal organs. The potential of PIMBA in imaging breast cancer was evaluated in Lewis rats bearing syngeneic RMT breast cancers, a cancer that closely mimics

Sulphur and oxygen sequestration of n-C 37 and n-C 38 unsaturated ketones in an immature kerogen and the release of their carbon skeletons during early stages of thermal maturation

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Koopmans, Martin P.; Schaeffer-Reiss, Christine; de Leeuw, Jan W.; Lewan, Michael D.; Maxwell, James R.; Schaeffer, Philippe; Sinninghe Damsté, Jaap S.

1997-06-01

Sedimentary rock from the Gessoso-solfifera Formation (Messinian) in the Vena del Gesso Basin (northern Italy) containing immature ( Ro = 0.25%) S-rich organic matter was artificially matured by hydrous pyrolysis at temperatures from 160 to 330°C for 72 h to study the diagenetic fate of n-C 37 and n-C 38 di- and tri-unsaturated methyl and ethyl ketones (alkenones) biosynthesised by several prymnesiophyte algae. During early diagenesis, the alkenones are incorporated into the kerogen by both sulphur and oxygen cross-linking as indicated by chemical degradation experiments with the kerogen of the unheated sample. Heating at temperatures between 160 and 260°C, which still represents early stages of thermal maturation, produces large amounts (up to 1 mg/g TOC) of S-bound, O-bound, and both S- and O-bound n-C 37 and n-C 38 skeletons, saturated n-C 37 and n-C38 methyl, ethyl, and mid-chain ketones, C 37 and C 38 mid-chain 2,5-di- n-alkylthiophenes, C 37 and C 38 1,2-di- n-alkylbenzenes, and C 37 and C 38n-alkanes. With increasing thermal maturation, three forms of the n-C 37 and n-C 38 skeletons are relatively stable (saturated hydrocarbons, 1,2-di- n-alkylbenzenes and saturated ketones), whereas the S- and O-bound skeletons are relatively labile. These results suggest that in natural situations saturated ketones with an n-C 37 and n-C 38 skeleton can be expected as well as the corresponding hydrocarbons.

Sulphur and oxygen sequestration of n-C37 and n-C38 unsaturated ketones in an immature kerogen and the release of their carbon skeletons during early stages of thermal maturation

Science.gov (United States)

Koopmans, M.P.; Schaeffer-Reiss, C.; De Leeuw, J. W.; Lewan, M.D.; Maxwell, J.R.; Schaeffer, P.; Sinninghe, Damste J.S.

1997-01-01

Sedimentary rock from the Gessoso-solfifera Formation (Messinian) in the Vena del Gesso Basin (northern Italy) containing immature (Ro = 0.25%) S-rich organic matter was artificially matured by hydrous pyrolysis at temperatures from 160 to 330??C for 72 h to study the diagenetic fate of n-C37 and n-C38 di-and tri-unsaturated methyl and ethyl ketones (alkenones) biosynthesised by several prymnesiophyte algae. During early diagenesis, the alkenones are incorporated into the kerogen by both sulphur and oxygen cross-linking as indicated by chemical degradation experiments with the kerogen of the unheated sample. Heating at temperatures between 160 and 260??C, which still represents early stages of thermal maturation, produces large amounts (up to 1 mg/g TOC) of S-bound, O-bound, and both S-and O-bound n-C37 and n-C38 skeletons, saturated n-C37 and n-C38 methyl, ethyl, and mid-chain ketones, C37 and C38 mid-chain 2,5-di-n-alkylthiophenes, C37 and C38 1,2-di-n-alkylbenzenes, and C37 and C38 n-alkanes. With increasing thermal maturation, three forms of the n-C37 and n-C38 skeletons are relatively stable (saturated hydrocarbons, 1,2-di-n-alkylbenzenes and saturated ketones), whereas the S-and O-bound skeletons are relatively labile. These results suggest that in natural situations saturated ketones with an n-C37 and n-C38 skeleton can be expected as well as the corresponding hydrocarbons. Copyright ?? 1997 Elsevier Science Ltd.

3-Chloro-2-ethyl-6-nitro-2H-indazole

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Mohamed Mokhtar Mohamed Abdelahi

2017-05-01

Full Text Available In the title compound, C9H8ClN3O2, the orientation of the ethyl substituent is partly determined by an intramolecular C—H...Cl hydrogen bond. The indazole moiety is slightly folded with an angle of 0.70 (8° between the five- and six-membered rings. In the crystal, molecules pack in layers parallel to [100] through C—H...π(ring and N...;O...π(ring interactions.

Identification of N-arylsulfonylpyrimidones as anticancer agents.

Science.gov (United States)

Subramanian, Santhosh; Boggu, Pulla Reddy; Yun, Jieun; Jung, Sang-Hun

2018-03-01

For confirming the role of five membered ring of imidazolidinone moiety of N-arylsulfonylimidazolidinones (7) previously reported with highly potent anticancer agent, a series of N-arylsulfonylpyrimidones (10a-g) and N-arylsulfonyltetrahydropyrimidones (11a-e) were prepared and their anti-proliferating activity was measured against human cancer cell lines (renal ACHN, colon HCT-15, breast MDA-MB-231, lung NCI-H23, stomach NUGC-3, and prostate PC-3) using XTT assay. Among them, 1-(1-acetylindolin-5-ylsulfonyl)-4-phenyltetrahydropyrimidin-2(1H)-one (11d, mean GI 50  = 3.50 µM) and ethyl 5-(2-oxo-4-phenyltetrahydropyrimidin-1(2H)-ylsulfonyl)-indoline-1-carboxylate (11e, mean GI 50  = 0.26 µM) showed best growth inhibitory activity against human cancer cell lines. Considering the activity results, N-arylsulfonyltetrahydropyrimidones (11) exhibited more potent activity compared to N-arylsulfonylpyrimidones (10) and comparable activity to N-arylsulfonylimidazolidinones (7). Especially, tetrahydropyrimidin-2(1H)-one analogs containing acylindolin-5-ylsulfonyl moiety at position 1 demonstrated their strong growth inhibitory activity against human cancer cell lines.

Improvement of DNA transfer frequency and transposon mutagenesis of Erwinia carotovora subsp. betavasculorum.

Science.gov (United States)

Rella, M; Axelrood, P E; Weinhold, A R; Schroth, M N

1989-01-01

The production of antibiotics and their role in microbial competition under natural conditions can be readily studied by the use of transposon mutants. Several antibiotic-producing strains of Erwinia carotovora subsp. betavasculorum were unable to accept foreign DNA. A plasmid delivery system was developed, using ethyl methanesulfonate mutagenesis, which entailed isolating E. carotovora subsp. betavasculorum mutants able to accept foreign DNA and transfer it to other strains. This enabled transposon mutagenesis of a wild-type antibiotic-producing strain of E. carotovora subsp. betavasculorum. Twelve antibiotic-negative mutants were isolated, and one of these showed a reduction in antibiotic production in vitro. Many of these mutants also showed a reduction in their ability to macerate potato tissue. The mutants were classified into four genetic groups on the basis of their genetic and phenotypic characteristics, indicating that several genes are involved in antibiotic biosynthesis by E. carotovora subsp. betavasculorum. PMID:2543291

Dielectric study of molecular association in the binary mixtures (2-ethyl-1-hexanol + alcohol) and (cyclohexane + alcohol) at 298.2 K

Energy Technology Data Exchange (ETDEWEB)

Ghanadzadeh, A. [Department of Chemistry, Guilan University, Rasht (Iran, Islamic Republic of)]. E-mail: aggilani@guilan.ac.ir; Ghanadzadeh, H. [Department of Chemical Engineering, Guilan University, Rasht (Iran, Islamic Republic of); Sariri, R. [Department of Chemistry, Guilan University, Rasht (Iran, Islamic Republic of); Ebrahimi, L. [Department of Chemistry, Guilan University, Rasht (Iran, Islamic Republic of)

2005-04-15

Experimental results of dielectric investigations of three binary mixtures (ethanol + 2-ethyl-1-hexanol), (n-butanol + 2-ethyl-1-hexanol), and (tert-butanol + 2-ethyl-1-hexanol) were reported for various mole fractions at 298.2 K. The variations of dipole moment and correlation factor, g, with mole fraction in these mixtures were investigated using a unified quasichemical method described by Durov. The molecular associations of (ethanol + cyclohexane), (n-butanol + cyclohexane), and (tert-butanol + cyclohexane) binary mixtures were also investigated using the static dielectric method. A similar trend was observed in the variation of the dipole moments with the solute mole fractions in the both binary systems (i.e., alcohol + 2-ethyl-1-hexanol and alcohol + cyclohexane)

Eficácia de imazethapyr e chlorimuron-ethyl em aplicações de pré-semeadura da cultura da soja Efficacy of imazethapyr and chlorimuron-ethyl in pre-sowing applications on soybean crop

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S.O. Procópio

2006-09-01

Full Text Available O trabalho teve como objetivo avaliar a ação dos herbicidas imazethapyr e chlorimuron-ethyl em aplicações de pré-semeadura da cultura da soja, visando o controle das plantas daninhas presentes antes da semeadura e a redução na emergência de plantas daninhas durante o ciclo da cultura. O experimento foi conduzido a campo, em área de produção de soja em sistema de plantio direto. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições, em esquema fatorial (4 x 4 + 1, sendo quatro tratamentos herbicidas [glyphosate (1,62 kg ha-1; glyphosate (1,62 kg ha-1 + imazethapyr (100 g ha-1; glyphosate (1,62 kg ha-1 + chlorimuron-ethyl (10 g ha-1; glyphosate (1,62 kg ha-1 + chlorimuron-ethyl (20 g ha-1] e quatro intervalos entre a aplicação dos herbicidas e a semeadura da soja (0, 1, 3 e 7 dias, mais uma testemunha não-dessecada. A adição dos herbicidas imazethapyr (100 g ha¹ e chlorimuron-ethyl (10 ou 20 g ha-1 junto ao glyphosate não melhorou o controle e também não diminuiu a rebrota posterior das plantas daninhas Digitaria insularis, Tridax procumbens e Leptochloa filiformis. Três dias antes da semeadura da soja foi o intervalo mínimo para que o controle dessas três espécies de plantas daninhas não fosse prejudicado pela operação de semeadura mecânica. Constatou-se que os tratamentos herbicidas não afetaram o número de plantas emergidas das espécies Sida santaremnensis, Digitaria insularis, Eleusine indica, Chamaesyce hirta, Bidens pilosa e Senna obtusifolia. Apenas para a espécie Althernantela tenella foi verificado que a adição de imazethapyr ou de chlorimuron-ethyl junto ao glyphosate reduziu a emergência dessa planta daninha na área, mostrando eficiência em pré-emergência. Todos os tratamentos herbicidas aplicados em pré-semeadura proporcionaram maior produtividade da cultura da soja em relação à testemunha não-dessecada, mas o incremento dos herbicidas imazethapyr e

Sensitive Bioanalytical Methods for Mustard Gas Exposure Diagnosis

Science.gov (United States)

2006-11-01

bis (2-chloreoethyl0-1- nitrosourea ), thio-TEPA (N, N’N’-triethylenethiophosphoramide), busulfan (1, 4-butanediol dimethanesulfonate), MNNG (1...N- nitrosourea ), mounting solution, sucrose, and colloidal gold solution were purchased from Sigma (St. Louis, MO). 2.2 Cell culture Frozen

Searching for trans ethyl methyl ether in Orion KL.

Science.gov (United States)

Tercero, B; Cernicharo, J; López, A; Brouillet, N; Kolesniková, L; Motiyenko, R A; Margulès, L; Alonso, J L; Guillemin, J-C

2015-10-01

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH 3 CH 2 OCH 3 , through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH 3 CH 2 CH 2 OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 10 15 cm -2 and ≤(1.0 ± 0.2)× 10 15 cm -2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH 3 OCOH, CH 3 CH 2 OCOH, CH 3 OCH 3 , CH 3 OH, and CH 3 CH 2 OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N (CH 3 OCH 3 )/ N (tEME) ≥ 150 in the compact ridge of Orion.

DNA crosslinking and cytotoxicity in normal and transformed human cells treated with antitumor nitrosoureas.

Science.gov (United States)

Erickson, L C; Bradley, M O; Ducore, J M; Ewig, R A; Kohn, K W

1980-01-01

Normal (IMR-90) and simian virus 40-transformed (VA-13) human embryo cells were treated with antitumor nitrosoureas, and the effects on cell viability and cell DNA were compared. All six nitrosoureas tested were more toxic to VA-13 cells than to IMR-90 cells as measured by decrease in cell proliferation or in colony formation. The nitrosoureas capable of generating alkylisocyanates produced a smaller difference between the cell types than did derivatives lacking this capacity. DNA damage was measured by alkaline elution in cells treated with four chloroethylnitrosoureas. Whereas VA-13 cells exhibited dose-dependent interstrand crosslinking, little or none was detected in IMR-90 cells. The IMR-90 cells, however, exhibited at least as much DNA-protein crosslinking as did VA-13 cells. The results can be interpreted in terms of a possible difference in DNA repair between the cell lines. PMID:6928639

Regulation of spermidine/spermine N1-acetyltransferase in L6 cells by polyamines and related compounds.

Science.gov (United States)

Erwin, B G; Pegg, A E

1986-01-01

Exposure of rat L6 cells in culture to exogenous polyamines led to a very large increase in the activity of spermidine/spermine N1-acetyltransferase. Spermine was more potent than spermidine in bringing about this increase, but in both cases the elevated acetyltransferase activity increased the cellular conversion of spermidine into putrescine. The N1-acetyltransferase turned over very rapidly in the L6 cells, with a half-life of 9 min after spermidine and 18 min after spermine. A wide variety of synthetic polyamine analogues also brought about a substantial induction of spermidine/spermine N1-acetyltransferase activity. These included sym-norspermidine, sym-norspermine, sym-homospermidine, N4-substituted spermidine derivatives, 1,3,6-triaminohexane, 1,4,7-triaminoheptane and deoxyspergualin, which were comparable with spermidine in their potency, and N1N8-bis(ethyl)spermidine, N1N9-bis(ethyl)homospermidine, methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone) and 1,1'-[(methylethanediylidene)dinitrilo]bis(3-amino-guanidine ), which were even more active than spermidine. It is suggested that these polyamine analogues may bring about a decrease in cellular polyamines not only by inhibiting biosynthesis but by stimulating the degradation of spermidine into putrescine. PMID:3800951

Analysis and interpretation of specific ethanol metabolites, ethyl sulfate, and ethyl glucuronide in sewage effluent for the quantitative measurement of regional alcohol consumption.

Science.gov (United States)

Reid, Malcolm J; Langford, Katherine H; Mørland, Jørg; Thomas, Kevin V

2011-09-01

The quantitative measurement of urinary metabolites in sewage streams and the subsequent estimation of consumption rates of the parent compounds have previously been demonstrated for pharmaceuticals and narcotics. Ethyl sulfate and ethyl glucuronide are excreted in urine following the ingestion of alcohol, and are useful biomarkers for the identification of acute alcohol consumption. This study reports a novel ion-exchange-mediated chromatographic method for the quantitative measurement of ethyl sulfate and ethyl glucuronide in sewage effluent, and presents a novel calculation method for the purposes of relating the resulting sewage concentrations with rates of alcohol consumption in the region. A total of 100 sewage samples covering a 25-day period were collected from a treatment plant servicing approximately 500,000 people, and analyzed for levels of ethyl sulfate and ethyl glucuronide. The resulting data were then used to estimate combined alcohol consumption rates for the region, and the results were compared with alcohol related sales statistics for the same region. Ethyl glucuronide was found to be unstable in sewage effluent. Ethyl sulfate was stable and measurable in all samples at concentrations ranging from 16 to 246 nM. The highest concentrations of the alcohol biomarker were observed during weekend periods. Sixty one percent of the total mass of ethyl sulfate in sewage effluent corresponds to alcohol consumption on Friday and Saturday. Sales statistics for alcohol show that consumption in the region is approximately 6,750 kg/d. The quantity of ethyl sulfate passing through the sewage system is consistent with consumption of 4,900 to 7,800 kg/d.   Sewage epidemiology assessments of ethyl sulfate can provide accurate estimates of community alcohol consumption, and detailed examination of the kinetics of this biomarker in sewage streams can also identify time-dependent trends in alcohol consumption patterns. 2011 by the Research Society on Alcoholism.

Directed mutagenesis affects recombination in Azospirillum brasilense nif genes

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C.P. Nunes

2000-12-01

Full Text Available In order to improve the gene transfer/mutagenesis system for Azospirillum brasilense, gene-cartridge mutagenesis was used to replace the nifD gene with the Tn5 kanamycin resistance gene. The construct was transferred to A. brasilense by electrotransformation. Of the 12 colonies isolated using the suicide plasmid pSUP202 as vector, only four did not show vector integration into the chromosome. Nevertheless, all 12 colonies were deficient in acetylene reduction, indicating an Nif- phenotype. Four Nif- mutants were analyzed by Southern blot, using six different probes spanning the nif and Km r genes and the plasmid vector. Apparently, several recombination events occurred in the mutant genomes, probably caused mainly by gene disruption owing to the mutagenesis technique used: resistance gene-cartridge mutagenesis combined with electrotransformation.Com o objetivo de melhorar os sistemas de transferência gênica e mutagênese para Azospirillum brasilense, a técnica de mutagênese através do uso de um gene marcador ("gene-cartridge mutagenesis" foi utilizada para substituir a região genômica de A. brasilense correspondente ao gene nifD por um segmento de DNA do transposon Tn5 contendo o gene que confere resistência ao antibiótico canamicina. A construção foi transferida para a linhagem de A. brasilense por eletrotransformação. Doze colônias transformantes foram isoladas com o plasmídeo suicida pSUP202 servindo como vetor. Dessas, somente quatro não possuíam o vetor integrado no cromossomo da bactéria. Independentemente da integração ou não do vetor, as 12 colônias foram deficientes na redução do gás acetileno, evidenciando o fenótipo Nif -. Quatro mutantes Nif - foram analisados através da técnica de Southern blot, utilizando-se seis diferentes fragmentos contendo genes nif, de resistência à canamicina e do vetor como sondas. Os resultados sugerem a ocorrência de eventos recombinacionais variados no genoma dos mutantes. A

Comparison of influence of carmustine and new proline analog of nitrosourea on antioxidant system in breast carcinoma cells (MCF-7).

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Stankiewicz-Kranc, Anna; Miltyk, Wojciech; Skrzydlewska, Elzbieta

2010-01-01

The high toxicity and low selectivity of carmustine restrict its application in anticancer therapy. Therefore, proline analogs of nitrosourea have been synthesized to obtain compounds whose action on neoplastic cells is characterized by higher selectivity. The present studies have aimed at examining the influence of carmustine and a new proline analog of nitrosourea on the redox system of fibroblasts and breast cancer cells (MCF-7). Carmustine and the proline analog of nitrosourea caused an increase in hydrogen peroxide concentration both in fibroblasts and MCF-7 cells. Moreover, administration of carmustine and the new analog of nitrosourea caused a decrease in the activity of antioxidant enzymes. Observed changes in the antioxidant system correlated with an increase in concentration of dityrosine, as well as a decrease in tryptophan concentration. Changes in the antioxidant system were also accompanied by intensification of the lipid peroxidation process. In conclusion, carmustine and proline analog of nitrosourea produce similar changes in the antioxidant system in normal and cancer cells and are responsible for oxidative stress.

Optimización del proceso de esterificación química del destilado de desodorización del aceite de soja previamente saponificado y acidulado

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Barrera-Arellano, Daniel

2002-06-01

Full Text Available In this research work, it was optimized the reaction conditions for the chemistry esterification of unsaponifiable matter in soybean oil deodorizer distillate. The process involves (i alkaline hydrolysis of saponifiable matter; (ii acidulation of soaps and (iii acid catalyzed esterification of resulting total fatty acid. To determine the best process conditions to get the higher conversion rates of total fatty acids to ethylic esters, preserving the tocopherols, it was used, to analyze the results, the response surface methodology in a 2nd order factorial planning. In the step (i saponification of soybean oil deodorizer distillate saponifiable matter using NaOH:total fatty acids molar ratio = 2:1, temperature = 80º C and reaction time of 40 min. In the step (ii the resulting soaps were rapidly and stoichiometrically converted in free fatty acids with sulfuric acid (23 %, using an acid molar excess of 50 %, at 80º C, for 40 min and under atmospheric pressure. In the step (iii the optima conditions for the esterification reaction of soybean oil deodorizer distillate were: ethanol:total fatty acids molar ratio from 6.4 to 11.2:1, SO2H4 concentration from 0.9 to 1.5 % and reaction time from 1.3 to 2.6 h, with ethyl esters conversion rates up to 98 %. The mathematical model obtained is predictive and statistically significant (pEn esta investigación fueron optimizadas las condiciones de reacción de esterificación de la materia saponificable del destilado de desodorización del aceite de soja. El proceso engloba (i hidrólisis alcalina da materia saponificable; (ii acidulación de los jabones y (iii esterificación catalizada por ácido de los ácidos grasos totales resultantes. Las condiciones óptimas del proceso, para obtener el mayor rendimiento en ésteres etílicos y perdidas mínimas de tocoferoles, fueron determinadas usando la metodología de superficie de respuesta de un diseño factorial completo de 2a orden. Etapa (i saponificación

RAFT Aqueous Dispersion Polymerization of N-(2-(Methacryloyloxy)ethyl)pyrrolidone: A Convenient Low Viscosity Route to High Molecular Weight Water-Soluble Copolymers.

Science.gov (United States)

Cunningham, Victoria J; Derry, Matthew J; Fielding, Lee A; Musa, Osama M; Armes, Steven P

2016-06-28

RAFT solution polymerization of N -(2-(methacryoyloxy)ethyl)pyrrolidone (NMEP) in ethanol at 70 °C was conducted to produce a series of PNMEP homopolymers with mean degrees of polymerization (DP) varying from 31 to 467. Turbidimetry was used to assess their inverse temperature solubility behavior in dilute aqueous solution, with an LCST of approximately 55 °C being observed in the high molecular weight limit. Then a poly(glycerol monomethacylate) (PGMA) macro-CTA with a mean DP of 63 was chain-extended with NMEP using a RAFT aqueous dispersion polymerization formulation at 70 °C. The target PNMEP DP was systematically varied from 100 up to 6000 to generate a series of PGMA 63 -PNMEP x diblock copolymers. High conversions (≥92%) could be achieved when targeting up to x = 5000. GPC analysis confirmed high blocking efficiencies and a linear evolution in M n with increasing PNMEP DP. A gradual increase in M w / M n was also observed when targeting higher DPs. However, this problem could be minimized ( M w / M n RAFT aqueous dispersion polymerization of NMEP was approximately four times faster than the RAFT solution polymerization of NMEP in ethanol when targeting the same DP in each case. This is perhaps surprising because both 1 H NMR and SAXS studies indicate that the core-forming PNMEP chains remain relatively solvated at 70 °C in the latter formulation. Moreover, dissolution of the initial PGMA 63 -PNMEP x particles occurs on cooling from 70 to 20 °C as the PNMEP block passes through its LCST. Hence this RAFT aqueous dispersion polymerization formulation offers an efficient route to a high molecular weight water-soluble polymer in a rather convenient low-viscosity form. Finally, the relatively expensive PGMA macro-CTA was replaced with a poly(methacrylic acid) (PMAA) macro-CTA. High conversions were also achieved for PMAA 85 -PNMEP x diblock copolymers prepared via RAFT aqueous dispersion polymerization for x ≤ 4000. Again, better control was achieved when

Influência do etil-trinexapac no acúmulo, na distribuição de nitrogênio (15N e na massa de grãos de arroz de terras altas Influence of ethyl-trinexapac on 15N accumulation and distribution and on highland rice yield

Directory of Open Access Journals (Sweden)

Rita de Cássia Félix Alvarez

2007-12-01

regulador de crescimento vegetal reduziu a altura das plantas e o acúmulo de 15N na panícula e promoveu a redistribuição do 15N absorvido e o aumento do 15N acumulado na raiz, colmo+bainha e folhas. A contribuição de 15N absorvido, em cada estádio estudado, para formação da panícula aumentou com o desenvolvimento das plantas, em menor proporção na presença do regulador de crescimento utilizado. O etil-trinexapac influenciou negativamente os componentes do rendimento e a massa de grãos de arroz.The high rice grain yields ensured by sprinkler irrigation have encouraged the use of higher fertilizer doses, mainly the nitrogen fertilizers. However, an improper management of nitrogen fertilization may result in plant lodging. Application of plant regulators may redirect assimilates to grain production while limiting the vegetative growth. This study aimed to: evaluate the influence of the growth regulator Ethyl-trinexapac on plant growth parameters and on 15N accumulation and distribution in the whole plant and plant components, and determine the contribution of nitrogen taken up in different developmental stages in panicle formation, yield components and rice yield. The experiment was carried out under controlled greenhouse conditions. The treatments consisted of application or not of a plant growth regulator (0 and 200 g active ingredient ha-1 of ethyl-trinexapac at four plant development stages (1 - beginning to end of tillering; 2 - end of tillering and flower differentiation; 3 - flower differentiation to flowering; 4 - flowering until physiological maturation. The experimental design was arranged in random blocks, in a 2 x 4 factorial scheme, with three replications. The plants were placed in a group of 48 pots. In a group of 24 pots with nutrient solution containing 15NH4SO4, plants were collected and separated in parts in the beginning of each pre-established plant development stage and at the end of each stage. In a second group (24 pots, pre-labeled plants

Synthesis and characterization of new alkylating agents 2-amino-4-phenyl thiazole

Energy Technology Data Exchange (ETDEWEB)

Sotelo, E.; Mocelo, R.; Suarez, M.; Gonzalez, L. [Laboratorio de Sintesis Organica, Facultad de Quimica, Universidad de la Habana, La Habana (Cuba)

1996-10-01

Starting with 2-amino-4-phenyl thiazole (1), the preparation of two new nitrosoureas 1-(4-phenyl-2-thiazole)-3-(2-chloroethyl)-3-nitrosourea (3), 1-(5-bromo-4-phenyl-thiazolyl)-3-(2-chloroethyl)-3-nitrosourea (8) and the N,N-bis (2-chloroethyl)-4-phenyl-2-amino thiazole (9) is reported. 9 refs.

Extremely decreased release of prostaglandin E-like activity from chopped lung of ethyl linolenate-supplemented rats

DEFF Research Database (Denmark)

Hansen, Harald S.; Jensen, B.; Fjalland, B.

1983-01-01

Three groups of weanling male rats were reared on a fat-free diet for 13 weeks. One group received only the fat-free diet (FF rats), the other 2 groups received the fat-free diet and a daily supplement of 2 energy% ethyl linoleate ([n-6] rats), or 2 energy% ethyl linolenate ([n-3] rats). The chop......). The chopped lung preparation was used to illustrate an in vitro prostaglandin formation. PGE-like activity was quantified on rat stomach strip. The release of PGE-like activity expressed as ng PGE-equivalent per g lung tissue (mean±SD) was 23±7,...

Diet-animal fractionation of nitrogen stable isotopes reflects the efficiency of nitrogen assimilation in ruminants.

Science.gov (United States)

Cantalapiedra-Hijar, G; Ortigues-Marty, I; Sepchat, B; Agabriel, J; Huneau, J F; Fouillet, H

2015-04-14

The natural abundance of ¹⁵N in animal proteins (δ¹⁵Nanimal) is greater than that in the diet consumed by the animals (δ¹⁵Ndiet), with a discrimination factor (Δ¹⁵N = δ¹⁵Nanimal - δ¹⁵Ndiet) that is known to vary according to nutritional conditions. The objectives of the present study were to test the hypothesis that Δ¹⁵N variations depend on the efficiency of nitrogen utilisation (ENU) in growing beef cattle, and to identify some of the physiological mechanisms responsible for this N isotopic fractionation in ruminants. Thus, we performed the regression of the Δ¹⁵N of plasma proteins obtained from thirty-five finishing beef cattle fed standard and non-conventional diets against different feed efficiency indices, including ENU. We also performed the regression of the Δ¹⁵N of different ruminant N pools (plasma and milk proteins, urine and faeces) against different splanchnic N fluxes obtained from multi-catheterised lactating dairy cows. The Δ¹⁵N of plasma proteins was negatively correlated with feed efficiency indices in beef cattle, especially ENU (body protein gain/N intake) and efficiency of metabolisable protein (MP) utilisation (body protein gain/MP intake). Although Δ¹⁵N obtained from different N pools in dairy cows were all negatively correlated with ENU, the highest correlation was found when Δ¹⁵N was calculated from plasma proteins. Δ¹⁵N showed no correlation with urea-N recycling or rumen NH₃ absorption, but exhibited a strong correlation with liver urea synthesis and splanchnic amino acid metabolism, which points to a dominant role of splanchnic tissues in the present N isotopic fractionation study.

Response of melanoma tumor phospholipid metabolism to chloroethyle nitrosourea: a high resolution proton NMR spectroscopy study.

Science.gov (United States)

Morvan, Daniel; Demidem, Aïcha; Madelmont, Jean-Claude

2003-07-01

Phospholipid metabolism is tightly involved in tumor growth regulation and tumor cell survival. The response of phospholipid metabolism to chloroethyle nitrosourea treatment is investigated in a murine B16 melanoma model. Measurements of phospholipid derivatives are performed on intact tumor tissue samples using one- and two-dimensional proton NMR spectroscopy. During the tumor growth inhibition phase under treatment, tumors overexpress phosphocholine, phosphoethanolamine, glycerophosphocholine and glycerophosphoethanolamine, whereas phosphatidylcholine and phosphatidylethanolamine levels are maintained to control levels. During re-growth, which remained quantitatively much below control growth, chloroethyle nitrosourea-treated melanoma tumors overexpress phosphocholine and phosphoethanolamine only. In treated melanoma, phosphatidylcholine levels show an inverse relationship with tumor growth rates. In conclusion, chloroethyle nitrosourea-treated melanoma tumors maintain their phosphatidylcholine levels and exhibit transformed phospholipid metabolism phenotype, by mechanisms that could participate in tumor cell survival.

Sulphur and oxygen sequestration of n-C{sub 37} and n-C{sub 38} unsaturated ketones in an immature kerogen and the release of their carbon skeletons during early stages of thermal maturation

Energy Technology Data Exchange (ETDEWEB)

Koopmans, M.P.; De Leeuw, J.W.; Damste, J.S.S. [Netherlands Institute for Sea Research (NIOZ), Den Burg (Netherlands)] [and others

1997-06-01

Sedimentary rock from the Gessoso-solfifera Formation (Messinian) in the Vena del Gesso Basin (northern Italy) containing immature (R{sub o} = 0.25%) S-rich organic matter was artificially matured by hydrous pyrolysis at temperatures from 160 to 330{degrees}C for 72 h to study the diagenetic fate of n-C{sub 37} and n-C{sub 38} di- and tri-unsaturated methyl and ethyl ketones (alkenones) biosynthesised by several prymnesiophyte algae. During early diagenesis, the alkenones are incorporated into the kerogen by both sulphur and oxygen cross-linking as indicated by chemical degradation experiments with the kerogen of the unheated sample. Heating at temperatures between 160 and 260{degrees}C, which still represents early stages of thermal maturation, produces large amounts (up to 1 mg/g TOC) of S-bound, O-bound, and both S- and O-bound n-C{sub 37} and n-C{sub 38} skeletons, saturated n-C{sub 37} and n-C{sub 38} methyl, ethyl, and mid-chain ketones, C{sub 37} and C{sub 38} mid-chain 2,5-di-n-alkylthiophenes, C{sub 37} and C{sub 38} 1,2-di-n-alkylbenzenes, and C{sub 37} and C{sub 38} n-alkanes. With increasing thermal maturation, three forms of the n-C{sub 37} and n-C{sub 38} skeletons are relatively stable (saturated hydrocarbons, 1,2-di-n-alkylbenzenes and saturated ketones), whereas the S- and O-bound skeletons are relatively labile. These results suggest that in natural situations saturated ketones with an n-C{sub 37} and n-C{sub 38} skeleton can be expected as well as the corresponding hydrocarbons. 58 refs., 8 figs., 2 tabs.

Cytochrome P-450 inactivation by 3-alkylsydnones. Mechanistic implications of N-alkyl and N-alkenyl heme adduct formation

International Nuclear Information System (INIS)

Grab, L.A.; Swanson, B.A.; Ortiz de Montellano, P.R.

1988-01-01

Incubation of 3-(2-phenylethyl)-4-methylsydnone (PMS) with liver microsomes from phenobarbital-pretreated rats or with reconstituted cytochrome P-450b results in loss of the enzyme chromophore. Chromophore loss is NADPH-dependent even though the sydnone decomposes by an oxygen- but not enzyme-dependent process to give pyruvic acid and, presumably, the (2-phenylethyl)diazonium cation. N-(2-Phenylethyl)protoporphyrin IX and N-(2-phenylethenyl)protoporphyrin IX have been isolated from the livers of rats treated with PMS. Both deuteriums are retained in the N-(2-phenylethyl) adduct derived from 3-(2-phenyl[1,1- 2 H]ethyl)-4-methylsydnone, but one deuterium is lost in the N-(2-phenylethenyl) adduct. The N-(2-phenylethyl) to N-(2-phenylethenyl) adduct ratio is increased by deuterium substitution. Electron paramagnetic resonance (EPR)-spin trapping studies show that carbon radicals are formed in incubations of the sydnones with liver microsomes but by a process that is independent of chromophore destruction. It is proposed that the 2-phenylethyl radical formed by electron transfer to the sydnone-derived (2-phenylethyl)diazonium cation adds to the prosthetic heme group to give the N-(2-phenylethyl) adduct. This alkylation reaction is similar to that observed with (2-phenylethyl)hydrazine. Autoxidation of the Fe-CH(CH 2 Ph)-N bridged species expected from insertion of 2-phenyldiazoethane into one of the heme Fe-N bonds is proposed to explain the unprecedented introduction of a double bond into the N-(2-phenylethenyl)adduct

The mutagenesis and breeding of high productive strains of streptomyces jingyangensis '5406'

International Nuclear Information System (INIS)

Qi Hongyan; Yin Xinyun

1988-03-01

The purpose of these experiments is to explore the mutagenesis rhythm and breed high productive strains of actinomycete '5406'. The single colony agar pieces of strain F 358 were treated with fast neutron and 60 Co-γ ray irradiation Two mutants have been selected from 20025 treated single colonies. The output of cytokinins from them is higher than from strain F 358 . The original strain 'Mu-Tan-al' rejuvenated by freezing was treated with several physical and chemical mutagens. The mutagenesis rhythm has been summed up tentatively. Eight mutants obtained from 93014 treated single colonies produced more '5406' antibiotics than that of strain 'Mu-Tan-al,. The effect of mutant 'N2-10-Ra3' was the best

Synthesis, structure, computational and in-silico anticancer studies of N,N-diethyl-N‧-palmitoylthiourea

Science.gov (United States)

Asegbeloyin, Jonnie Niyi; Oyeka, Ebube Evaristus; Okpareke, Obinna; Ibezim, Akachukwu

2018-02-01

A new potential ONS donor ligand N,N-diethyl-N‧-palmitoylthiourea (PACDEA) with the molecular formular C21H42N2OS has been synthesized and characterized by ESI-MS, UV, FTIR 1H and 13C NMR spectroscopy and single X-ray crystallography. The asymmetric molecules crystallized in the centrosymmetric structure of monoclinic crystal system with space group P21/c. In the crystal structure of the compound, molecules are linked in a continuous chain by intermolecular Nsbnd H⋯Odbnd C hydrogen bonds, which stabilized the crystal structure. The palmitoyl moiety and N (2)-ethyl group lie on a plane, while the thiocarbonyl moiety is twisted and lying othorgonal to the plane. Non-covalent interaction (NCI) analysis on the hydrogen bonded solid state structure of the molecule revealed the presence of a significant number of non-covalent interactions including intermolecular hydrogen bonding interactions, Csbnd Hsbnd -lone pair interactions, weak Van der Waals interactions, and steric/ring closure interactions. The NCI analysis also showed the presence of intramolecular stabilizing Csbnd H⋯Odbnd C and Csbnd H⋯Sdbnd C interactions. Docking simulation revealed that the compound interacted favourably with ten selected validated anticancer drug targets, which is an indication that the compound could possess some anticancer properties.

A mutation in the mitochondrial fission gene Dnm1l leads to cardiomyopathy.

Directory of Open Access Journals (Sweden)

Houman Ashrafian

2010-06-01

Full Text Available Mutations in a number of genes have been linked to inherited dilated cardiomyopathy (DCM. However, such mutations account for only a small proportion of the clinical cases emphasising the need for alternative discovery approaches to uncovering novel pathogenic mutations in hitherto unidentified pathways. Accordingly, as part of a large-scale N-ethyl-N-nitrosourea mutagenesis screen, we identified a mouse mutant, Python, which develops DCM. We demonstrate that the Python phenotype is attributable to a dominant fully penetrant mutation in the dynamin-1-like (Dnm1l gene, which has been shown to be critical for mitochondrial fission. The C452F mutation is in a highly conserved region of the M domain of Dnm1l that alters protein interactions in a yeast two-hybrid system, suggesting that the mutation might alter intramolecular interactions within the Dnm1l monomer. Heterozygous Python fibroblasts exhibit abnormal mitochondria and peroxisomes. Homozygosity for the mutation results in the death of embryos midway though gestation. Heterozygous Python hearts show reduced levels of mitochondria enzyme complexes and suffer from cardiac ATP depletion. The resulting energy deficiency may contribute to cardiomyopathy. This is the first demonstration that a defect in a gene involved in mitochondrial remodelling can result in cardiomyopathy, showing that the function of this gene is needed for the maintenance of normal cellular function in a relatively tissue-specific manner. This disease model attests to the importance of mitochondrial remodelling in the heart; similar defects might underlie human heart muscle disease.

A mutation in Nischarin causes otitis media via LIMK1 and NF-κB pathways.

Directory of Open Access Journals (Sweden)

Michael Crompton

2017-08-01

Full Text Available Otitis media (OM, inflammation of the middle ear (ME, is a common cause of conductive hearing impairment. Despite the importance of the disease, the aetiology of chronic and recurrent forms of middle ear inflammatory disease remains poorly understood. Studies of the human population suggest that there is a significant genetic component predisposing to the development of chronic OM, although the underlying genes are largely unknown. Using N-ethyl-N-nitrosourea mutagenesis we identified a recessive mouse mutant, edison, that spontaneously develops a conductive hearing loss due to chronic OM. The causal mutation was identified as a missense change, L972P, in the Nischarin (NISCH gene. edison mice develop a serous or granulocytic effusion, increasingly macrophage and neutrophil rich with age, along with a thickened, inflamed mucoperiosteum. We also identified a second hypomorphic allele, V33A, with only modest increases in auditory thresholds and reduced incidence of OM. NISCH interacts with several proteins, including ITGA5 that is thought to have a role in modulating VEGF-induced angiogenesis and vascularization. We identified a significant genetic interaction between Nisch and Itga5; mice heterozygous for Itga5-null and homozygous for edison mutations display a significantly increased penetrance and severity of chronic OM. In order to understand the pathological mechanisms underlying the OM phenotype, we studied interacting partners to NISCH along with downstream signalling molecules in the middle ear epithelia of edison mouse. Our analysis implicates PAK1 and RAC1, and downstream signalling in LIMK1 and NF-κB pathways in the development of chronic OM.

THE PHOTOELECTROCHEMICAL ETCHING AS A TOOL FOR GaN GAS SENSOR FABRICATION

OpenAIRE

V.Iu. Popa

2005-01-01

Whisker and columnar structures of GaN were fabricated using photoelectrochemical etching in KOH solution. The conductivity changes of the obtained structures to ethylic alcohol and hydrogen were studied. Optimized design for sensor fabrication is proposed.

Perfluorooctanesulfonate (PFOS) Conversion from N-Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) in male Sprague Dawley rats after inhalation exposure

International Nuclear Information System (INIS)

Chang, Sue; Mader, Brian T.; Lindstrom, Kent R.; Lange, Cleston C.; Hart, Jill A.; Kestner, Thomas A.; Schulz, Jay F.; Ehresman, David J.; Butenhoff, John L.

2017-01-01

Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) was one of the key building blocks for many of the perfluorooctanesulfonyl-based chemistry and laboratory studies have shown that EtFOSE can metabolically degrade to perfluorooctanesulfonate (PFOS). Non-occupational contribution sources to PFOS are thought to occur in general population via diets, drinking water, air and dust. For workers, however, the exposure route was mostly airborne and the exposure source was predominantly to precursor compounds such as EtFOSE. We undertook this study to investigate how much EtFOSE was converted to PFOS in the serum for male rats after 6 h of exposure to EtFOSE vapor (whole body) at ambient temperature, which simulated a work place exposure scenario. There were no abnormal clinical observations and all rats gained weight during study. Interim tail-vein blood samples, collected up to 21 days after exposure, were analyzed for Et-FOSE and PFOS concentrations by LC-MS/MS. Upon inhalation exposure, the biotransformation of EtFOSE to PFOS in serum in the male rats was rapid and very little EtFOSE was detected in the serum within 24 h after EtFOSE exposure. The highest conversion to PFOS in serum after exposure to EtFOSE vapor appeared to occur between Day 8−14 post exposure. Considering the potential surface and fur adsorption of test compound in the whole-body exposure system, our data would support that at least 10% of the inhaled EtFOSE was biotransformed to PFOS in the serum based on the range of lower 95% CI (confidence interval) values. This information is valuable because it quantitatively translates EtFOSE exposure into serum PFOS concentration, which serves as a matrix for internal dosimetry (of PFOS exposure) that can be used as an anchor across species as well as between different exposure routes. - Highlights: • First inhalation study reported in rats that investigates the conversion of a major precursor compound (EtFOSE) to form PFOS. • Systemic

Perfluorooctanesulfonate (PFOS) Conversion from N-Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) in male Sprague Dawley rats after inhalation exposure

Energy Technology Data Exchange (ETDEWEB)

Chang, Sue, E-mail: s.chang@mmm.com [Medical Department, 3M Company, St. Paul, MN 55144 (United States); Mader, Brian T., E-mail: bmader@mmm.com [Environmental Laboratory, 3M Company, St. Paul, MN 55144 (United States); Lindstrom, Kent R., E-mail: krlindstrom@mmm.com [Environmental Laboratory, 3M Company, St. Paul, MN 55144 (United States); Lange, Cleston C., E-mail: clange@mmm.com [Environmental Laboratory, 3M Company, St. Paul, MN 55144 (United States); Hart, Jill A., E-mail: jahart@mmm.com [Medical Department, 3M Company, St. Paul, MN 55144 (United States); Kestner, Thomas A., E-mail: takestner@mmm.com [Materials Resource Division, 3M Company, St. Paul, MN 55144 (United States); Schulz, Jay F., E-mail: jfschulz@mmm.com [Materials Resource Division, 3M Company, St. Paul, MN 55144 (United States); Ehresman, David J., E-mail: depqehr@gmail.com [Medical Department, 3M Company, St. Paul, MN 55144 (United States); Butenhoff, John L., E-mail: john.butenhoff@gmail.com [SaluTox, LLC, Lake Elmo, MN 55042 (United States)

2017-05-15

Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) was one of the key building blocks for many of the perfluorooctanesulfonyl-based chemistry and laboratory studies have shown that EtFOSE can metabolically degrade to perfluorooctanesulfonate (PFOS). Non-occupational contribution sources to PFOS are thought to occur in general population via diets, drinking water, air and dust. For workers, however, the exposure route was mostly airborne and the exposure source was predominantly to precursor compounds such as EtFOSE. We undertook this study to investigate how much EtFOSE was converted to PFOS in the serum for male rats after 6 h of exposure to EtFOSE vapor (whole body) at ambient temperature, which simulated a work place exposure scenario. There were no abnormal clinical observations and all rats gained weight during study. Interim tail-vein blood samples, collected up to 21 days after exposure, were analyzed for Et-FOSE and PFOS concentrations by LC-MS/MS. Upon inhalation exposure, the biotransformation of EtFOSE to PFOS in serum in the male rats was rapid and very little EtFOSE was detected in the serum within 24 h after EtFOSE exposure. The highest conversion to PFOS in serum after exposure to EtFOSE vapor appeared to occur between Day 8−14 post exposure. Considering the potential surface and fur adsorption of test compound in the whole-body exposure system, our data would support that at least 10% of the inhaled EtFOSE was biotransformed to PFOS in the serum based on the range of lower 95% CI (confidence interval) values. This information is valuable because it quantitatively translates EtFOSE exposure into serum PFOS concentration, which serves as a matrix for internal dosimetry (of PFOS exposure) that can be used as an anchor across species as well as between different exposure routes. - Highlights: • First inhalation study reported in rats that investigates the conversion of a major precursor compound (EtFOSE) to form PFOS. • Systemic

N-Oxide analogs of WAY-100635 : new high affinity 5-HT (1A) receptor antagonists

NARCIS (Netherlands)

Oberwinkler - Marchais, Sandrine; Nowicki, B; Pike, VW; Halldin, C; Sandell, J; Chou, YH; Gulyas, B; Brennum, LT; Farde, L; Wikstrom, H V

2005-01-01

WAY-100635 [N-(2-(1-(4-(2-methoxyphenyl)piperazinyl)ethyl))-N-(2-pyridinyl)cyclohexanecarboxamide] 1 and its O-des-methyl derivative DWAY 2 are well-known high affinity 5-HT1A receptor antagonists. which when labeled with carbon-II (beta(+): t(1/2) 20.4min) in the carbonyl group are effective

Reactions of alkylnitrosoureas in aqueous solution

International Nuclear Information System (INIS)

Snyder, J.K.; Stock, L.M.

1980-01-01

The acid- and base-catalyzed decompositions of N-methyl-,N,N'-dimethyl-, and N,N',N'-trimethyl-N-nitrosourea in aqueous solution have been studied. Below pH 2, the N-methyl compound undergoes both denitrosation and hydrolysis to yield methylurea, nitrous acid, methylamine, nitrogen, and carbon dioxide. The acid-catalyzed denitrosation and hydrolysis of the trimethylnitrosourea are somewhat more rapid than the corresponding reactions of N-methyl-N-nitrosourea. The solvent isotope effect, k/sub H 2 O//k/sub D 2 O/ = 1.3, and the absence of chloride ion catalysis suggest that the denitrosation reaction proceeds by a rate-determining proton transfer which is followed by the rapid loss of the nitroso group. The results for the hydrolysis reaction are compatible with a formulation in which a hydrate of the nitrosourea is protonated in a rate-determining step to form a tetrahedral intermediate which subsequently decomposes to yield methyldiazonium hydroxide and a carbamic acid derivative. The base-catalyzed reactions of the mono, di-, and trimethylnitrosoureas are first order in hydroxide ion over a broad pH range. The hydrolysis of N-methyl-N-nitrosourea yields methanol and derivatives of carbamic acid. Salt effects on the reaction rate are negligible except for the influence of lithium ion. The rate constants for the hydrolysis of the mono- and dimethyl compounds depend upon the buffer concentrationat pH 9.5. The rate constants for the hydrolysis of the trimethyl compound also depend upon the buffer concentration, but a limiting value is not achieved. The solvent isotope effect for the base-catalyzed reaction, the exchange reaction of water- 18 O with the carbonyl group of the urea, and the fact that N-methyl-N-nitrosourea is hydrolyzed about 2.2 x 10 4 times more rapidly than N,N',N'-trimethyl-N-nitrosourea suggest that the hydrolysis occurs by a mechanism in which a tetrahedral intermediate is formed

Breast Cancer and Early Onset Childhood Obesity: Cell Specific Gene Expression in Mammary Epithelia and Adipocytes

Science.gov (United States)

2007-07-01

G, Lee AV, McCarty M, Van Horn K, Chu O, Chou YC, Yang J, Guzman RC, Nandi S, Talamantes F. Growth and characterization of N-methyl-N- nitrosourea ...G, Lee AV, McCarty M, et al. Growth and characteriza- tion of N-methyl-N- nitrosourea -induced mammary tumors in intact and ovariectomized rats

Synthesis, in vitro pharmacologic characterization, and preclinical evaluation of N-[2-(1'-piperidinyl)ethyl]-3-[{sup 125}I]iodo-4-methoxybenzamide (P[{sup 125}I]MBA) for imaging breast cancer

Energy Technology Data Exchange (ETDEWEB)

John, Christy S. E-mail: radcsj@gwumc.edu; Bowen, Wayne D.; Fisher, Susan J.; Lim, Benjamin B.; Geyer, Brian C.; Vilner, Bertold J.; Wahl, Richard L

1999-05-01

The goal of this study was to investigate the potential use of a radioiodinated benzamide, N-[2-(1'-piperidinyl)ethyl]-3-iodo[{sup 125}I]-4-methoxybenzamide (P[{sup 125}I]MBA), a sigma receptor binding radioligand for imaging breast cancer. The chemical and radiochemical syntheses of PIMBA are described. The pharmacological evaluation of PIMBA was carried out for sigma-1 and sigma-2 receptor sites. The in vivo pharmacokinetics of the radioiodinated benzamide were determined in rats and comparison of P[{sup 125}I]MBA with Tc-99m sestamibi were made in a rat mammary tumor model. Sigma-1 affinity (K{sub i}) for PIMBA in guinea pig brain membranes using [{sup 3}H](+)pentazocine was found to be 11.82{+-}0.68 nM, whereas sigma-2 affinity in rat liver using [{sup 3}H]DTG (1,3-o-di-tolylguanidine) was 206{+-}11 nM. Sites in guinea pig brain membranes labeled by P[{sup 125}I]MBA showed high affinity for haloperidol, (+)-pentazocine, BD1008, and PIMBA (K{sub i}=4.87{+-}1.49,8.81{+-}1.97,0.057{+-}0.005,46.9{+-}1.8 nM), respectively). Competition binding studies were carried out in human ductal breast carcinoma cells (T47D). A dose-dependent inhibition of specific binding was observed with several sigma ligands. K{sub i} values for the inhibition of P[{sup 125}I]MBA binding in T47D cells for haloperidol, N-[2-(1'-piperidinyl)]ethyl]4-iodobenzamide (IPAB), N-(N-benzylpiperidin-4-yl)-4-iodobenzamide (4-IBP), and PIMBA were found to be 1.30{+-}0.07, 13{+-}1.5, 5.19{+-}2.3, 1.06{+-}0.5 nM, respectively. The in vitro binding data in guinea pig brain membranes and breast cancer cells confirmed binding to sigma sites. The saturation binding of P[{sup 125}I]MBA in T47D cells as studied by Scatchard analysis showed saturable binding, with a K{sub d}=94{+-}7 nM and a B{sub max}=2035{+-}305 fmol/mg of proteins. Biodistribution studies in Sprague-Dawley rats showed a rapid clearance of P[{sup 125}I]MBA from the normal organs. The potential of PIMBA in imaging breast cancer was

Catalytic Synthesis of Ethyl Ester From Some Common Oils ...

African Journals Online (AJOL)

Catalytic conversion of ethanol to fatty acid ethyl esters (FAEE) was carried out by homogeneous and heterogeneous transesterification of melon seed, shea butter and neem seed oils using NaOH, KOH and 5wt%CaO/Al2O3 catalyst systems respectively. Oil content of the seeds from n-hexane or hot water extract ranged ...

[Intravenous ethyl alcohol in metabolic resuscitation].

Science.gov (United States)

Agolini, G; Lipartiti, T; Zaffiri, O; Musso, L; Belloni, G P

1980-11-01

Intravenously administered ethyl alcohol may be effective as analgesic and hypotensive peripheric vasoactive drug. In the Intensive Care Departments parenteral ethanol administration is infrequent because no "sure dosage" can be suggested in adults and children. Liver, kidney and C.N.S. diseases can worsen; foetopathy can follow. Drug-ethanol interaction may be particularly important for some patients admitted in Intensive Care Departments. Often the potential caloric support cannot be fully utilized ("empty" calories) and seldom hyperventilation, hyperlactacidemia and impaired protein synthesis can follow.

UVC-mutagenesis in acetogens: resistance to methanol, ethanol, acetone, or n-butanol in recombinants with tailored genomes as the step in engineering of commercial biocatalysts for continuous CO₂/H₂ blend fermentations.

Science.gov (United States)

Kiriukhin, Michael; Tyurin, Michael; Gak, Eugene

2014-05-01

Time- and cost-efficient six-step UVC-mutagenesis was developed and validated to generate acetogen mutants with preliminary reduced genomes to prevent product inhibition in the to-be-engineered commercial biocatalysts. Genome reduction was performed via elimination of pta, ack, spo0A, spo0J and some pro-phage genes. UVC-mutants such as Clostridium sp. MT1784RG, Clostridium sp. MT653RG, Clostridium sp. MT896RG, and Clostridium sp. MT1962RG (all 4 share 97 % DNA homology with Clostridium ljungdahlii ATCC 55383) were selected based on resistance to methanol (3 M), ethanol (3.6 M), acetone (2.5 M), or n-butanol (0.688 M), respectively. As a part of the biocatalyst engineering algorithm, genome reduction step was associated with integration of attTn7 recognition sequence to the chromosomes of each of the above strains to prepare the defined integration sites for future integration of multi-copy synthetic operons encoding biosynthesis of methanol, ethanol, acetone or n-butanol. Reduced genome mutants had cell duplication times decreased compared to the same for the respective parental strains. All groups of mutants had decreased share of palmitic (C16:0) and increased share of oleic (C18:1) acids along with detection of isopropylstearate (C20) compared to the parental strains. Mutants resistant to acetone and n-butanol also had monounsaturated fatty acid (C20:1) not found in parental strains. Cyclopropane fatty acid (C21) was identified only in n-butanol resistant mutants.

In vitro evaluation of a new nitrosourea, TCNU, against human small cell lung cancer cell lines

DEFF Research Database (Denmark)

Roed, H; Vindeløv, L L; Spang-Thomsen, M

1987-01-01

The cytotoxic activity of a new nitrosourea, TCNU, was compared with that of BCNU in five human small cell lung cancer cell lines in vitro. TCNU was found to be equivalent or inferior to BCNU when compared on a microgram to microgram basis. If the potential of in vitro phase II trials for selection...... of new drugs can be validated, it can be concluded that TCNU is not superior to other nitrosoureas for the treatment of SCCL....

Synthesis and pharmacology of N-alkylated derivatives of the excitotoxin ibotenic acid

DEFF Research Database (Denmark)

Madsen, U; Dumpis, M A; Bräuner-Osborne, Hans

1998-01-01

Three amino-alkylated derivatives of the naturally occurring excitatory amino acid (EAA) receptor agonist ibotenic acid (Ibo) have been synthesized and tested pharmacologically. N-Methyl-Ibo (1a) and N-ethyl-Ibo (1b) were shown to be agonists at NMDA receptors (EC50 = 140 and 320 micro......-c and the potent NMDA agonist 2-amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid (AMAA) in order to elucidate the observed structure-activity data....

Copolymerization parameters of N-Methacryloyloxy tetrabromophthalimide with different vinyl monomers

International Nuclear Information System (INIS)

Mahmoud, A.A.

2005-01-01

N-Methacryloyloxytetrabromophthalimide (NMTP) was synthesized by the reaction of N-hydroxytetrabromophthalimide with either methacryloyl chloride or methacrylic acid in the presence of triethylamine or N, Ndicyclohexylcarbodiimide respectively. Binary copolymerization reactions of the prepared monomer with ethyl acrylate (EA), n-butyl methacrylate (n.BMA), tertiary butylacrylate (t.BA) and vinyl acetate (VA) were performed in methylene chloride at 65 degree C using 1 mol % azobisisobutylronitrile (AIBN) as initiator. The structure of the prepared monomer was investigated by IR and 1H NMR spectroscopy. The copolymer compositions were determined from bromine analysis. Copolymerization parameters for each system were calculated by the Fineman-Ross and Kelen-Tudos methods. The monomer reactivity ratios for the systems NMTP-EA, NMTP-n.BMA, NMTP-t.BA and NMTP-VA were found to be r1 0.180, r2 = 0.893, r1 = 0.025, r2 = 0.680, r1 0.014, r2 0.956 and r1 1.002, r2 1.004 respectively

Searching for trans ethyl methyl ether in Orion KL★,★★

Science.gov (United States)

Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

2015-01-01

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm−2 and ≤(1.0 ± 0.2)× 1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. PMID:26869726

Proline-linked nitrosoureas as prolidase-convertible prodrugs in human breast cancer cells.

Science.gov (United States)

Bielawski, Krzysztof; Bielawska, Anna; Słodownik, Tomasz; Bołkun-Skórnicka, Urszula; Muszyńska, Anna

2008-01-01

A number of novel proline-linked nitrosoureas (1-4) were synthesized and examined for cytotoxicity and influence on DNA and collagen biosynthesis in MDA-MB-231 and MCF-7 human breast cancer cells. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [(3)H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that compound 2, the most active of the series, proved to be only slightly less potent than carmustine. It has also been found that carmustine did not inhibit MCF&-7 cells prolidase activity, while compounds 1-4 significantly increased its activity, when used at 50-250 microM concentrations. Proline-linked nitrosoureas (1-4) also had lower ability to inhibit collagen biosynthesis in MCF-7 cells, compared to carmustine. The expression of beta(1)-integrin receptor and phosphorylated MAPK, ERK(1) and ERK(2) was significantly decreased in MCF-7 cells incubated for 24 h with 60 microM of compounds 2 and 4 compared to the control, untreated cells, whereas under the same conditions carmustine did not evoke any changes in expression of all these signaling proteins, as shown by Western immunoblot analysis. These results indicate the proline-linked nitrosoureas (1-4), represent multifunctional inhibitors of breast cancer cell growth and metabolism.

Alternative chemotherapeutic agents: nitrosoureas, cisplatin, irinotecan.

Science.gov (United States)

Carrillo, Jose A; Munoz, Claudia A

2012-04-01

Irinotecan, cisplatin, and nitrosoureas have a long history of use in brain tumors, with demonstrated efficacy in the adjuvant treatment of malignant gliomas. In the era of temozolomide with concurrent radiotherapy given as the standard of care, their use has shifted to treatment at progression or recurrence. Now with the widespread use of bevacizumab in the recurrent setting, irinotecan and other chemotherapies are seeing increased use in combination with bevacizumab and alone in the recurrent setting. The activity of these chemotherapeutic agents in brain tumors will likely ensure a place in the armamentarium of neuro-oncologists for many years. Published by Elsevier Inc.

Thermal phase behaviour of N-alkyl-N-methylpyrrolidinium and piperidinium bis(trifluoromethanesulfonyl)imide salts

International Nuclear Information System (INIS)

Henderson, W A; Jr, V G Young; Pearson, W; Passerini, S; Long, H C De; Trulove, P C

2006-01-01

The phases, ion crystal packing and thermal properties of the N-alkyl-N-methylpyrrolidinium and piperidinium bis(trifluoromethanesulfonyl)imide (PYR 1R TFSI and PIP 1R TFSI (subscript R = 1 for methyl and 2 for ethyl), respectively) salts are compared using powder and single-crystal x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The crystal structure of PIP 12 TFSI has been determined at 123 K. The salt crystallizes in the triclinic space group P1-bar with Z 8. Structural data are also reported for PYR 11 TFSI at 153 K and PIP 12 TFSI at 223 K. PIP 11 TFSI has identical ion crystal packing to the analogous pyrrolidinium salt PYR 11 TFSI. Since increasing the cation alkyl chain length to propyl or butyl (R = 3 or 4) reduces the melting point of the salts below room temperature, this study may provide valuable insight into why these pyrrolidinium and piperidinium salts form room-temperature ionic liquids

Solvation of ionic liquids based on N-methyl-N-alkyl morpholinium cations in dimethylsulfoxide – volumetric and compressibility studies

International Nuclear Information System (INIS)

Marcinkowski, Łukasz; Kloskowski, Adam; Czub, Jacek; Namieśnik, Jacek; Warmińska, Dorota

2015-01-01

Highlights: • In DMSO both volumes and compressibilities of ionic liquids were studied. • Molecular dynamics simulations were performed for all studied ionic liquids. • V Φ of DMSO solutions of [Mor 1,R ][TFSI] decrease with increasing IL concentration. • Results indicate that [Mor 1,R ][TFSI] are structure breakers in dimethylsulfoxide. • Obtained results are the consequence of the cation size of the ionic liquid. - Abstract: The density and sound velocity of the solutions of ionic liquids based on N-alkyl-N-methyl-morpholinium cations, N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-methyl-N-octyl-morpholinium bis(trifluoromethanesulfonyl)imide and N-decyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide in dimethylsulfoxide were measured at T = (298.15 to 318.15) K and at atmospheric pressure. The apparent molar volume and apparent molar compressibility values were evaluated from density and sound velocity values and fitted to the Masson equation from which the partial molar volume and partial molar isentropic compressibility of the ILs at infinite dilution were also calculated at working temperatures. By using the density values, the limiting apparent molar expansibilities were estimated. The effect of the alkyl chain length of the ILs and experimental temperature on these thermodynamic properties is discussed. In addition, molecular dynamics simulations were used to interpret the measured properties in terms of interactions of ILs with solvent molecules. Both, volumetric measurements results and molecular dynamics simulations for ionic liquids in dimethylsulfoxide were compared and discussed with results obtained for the same IL in acetonitrile

On the effect of N-GaN/P-GaN/N-GaN/P-GaN/N-GaN built-in junctions in the n-GaN layer for InGaN/GaN light-emitting diodes.

Science.gov (United States)

Kyaw, Zabu; Zhang, Zi-Hui; Liu, Wei; Tan, Swee Tiam; Ju, Zhen Gang; Zhang, Xue Liang; Ji, Yun; Hasanov, Namig; Zhu, Binbin; Lu, Shunpeng; Zhang, Yiping; Sun, Xiao Wei; Demir, Hilmi Volkan

2014-01-13

N-GaN/P-GaN/N-GaN/P-GaN/N-GaN (NPNPN-GaN) junctions embedded between the n-GaN region and multiple quantum wells (MQWs) are systematically studied both experimentally and theoretically to increase the performance of InGaN/GaN light emitting diodes (LEDs) in this work. In the proposed architecture, each thin P-GaN layer sandwiched in the NPNPN-GaN structure is completely depleted due to the built-in electric field in the NPNPN-GaN junctions, and the ionized acceptors in these P-GaN layers serve as the energy barriers for electrons from the n-GaN region, resulting in a reduced electron over flow and enhanced the current spreading horizontally in the n- GaN region. These lead to increased optical output power and external quantum efficiency (EQE) from the proposed device.

Expression of N-WASP is regulated by HiF1α through the hypoxia response element in the N-WASP promoter

Directory of Open Access Journals (Sweden)

Amrita Salvi

2017-03-01

Full Text Available Cancer cell migration and invasion involves temporal and spatial regulation of actin cytoskeleton reorganization, which is regulated by the WASP family of proteins such as N-WASP (Neural- Wiskott Aldrich Syndrome Protein. We have previously shown that expression of N-WASP was increased under hypoxic conditions. In order to characterize the regulation of N-WASP expression, we constructed an N-WASP promoter driven GFP reporter construct, N-WASPpro-GFP. Transfection of N-WASPpro-GFP construct and plasmid expressing HiF1α (Hypoxia Inducible factor 1α enhanced the expression of GFP suggesting that increased expression of N-WASP under hypoxic conditions is mediated by HiF1α. Sequence analysis of the N-WASP promoter revealed the presence of two hypoxia response elements (HREs characterized by the consensus sequence 5′-GCGTG-3′ at -132 bp(HRE1 and at -662 bp(HRE2 relative to transcription start site (TSS. Site-directed mutagenesis of HRE1(-132 but not HRE2(-662 abolished the HiF1α induced activation of N-WASP promoter. Similarly ChIP assay demonstrated that HiF1α bound to HRE1(-132 but not HRE2(-662 under hypoxic condition. MDA-MB-231 cells but not MDA-MB-231KD cells treated with hypoxia mimicking agent, DMOG showed enhanced gelatin degradation. Similarly MDA-MB-231KD(N-WASPpro-N-WASPR cells expressing N-WASPR under the transcriptional regulation of WT N-WASPpro but not MDA-MB-231KD(N-WASPproHRE1-N-WASPR cells expressing N-WASPR under the transcriptional regulation of N-WASPproHRE1 showed enhanced gelatin degradation when treated with DMOG. Thus indicating the importance of N-WASP in hypoxia induced invadopodia formation. Thus, our data demonstrates that hypoxia-induced activation of N-WASP expression is mediated by interaction of HiF1α with the HRE1(-132 and explains the role of N-WASP in hypoxia induced invadopodia formation.

Overmodulation Control in the Optimization of a H-PDLC Device with Ethyl Eosin as Dye

Directory of Open Access Journals (Sweden)

Manuel Ortuño

2013-01-01

Full Text Available The response of a H-PDLC device is improved by means of a two-step method. First, component optimization—initiator system, crosslinker, and cosolvent—enables the diffraction efficiency of the hologram to be maximized. Second, the use of N-methyl-2-pyrrolidone in combination with N-vinyl-2-pyrrolidone prevents the overmodulation in photopolymers containing ethyl eosin.

Mutagenesis in sequence encoding of human factor VII for gene therapy of hemophilia

Directory of Open Access Journals (Sweden)

B Kazemi

2009-12-01

Full Text Available "nBackground: Current treatment of hemophilia which is one of the most common bleeding disorders, involves replacement therapy using concentrates of FVIII and FIX .However, these concentrates have been associated with viral infections and thromboembolic complications and development of antibodies. "nThe use of recombinant human factor VII (rhFVII is effective  for the treatment of patients with  hemophilia A or B, who develop antibodies ( referred as inhibitors against  replacement therapy , because it induces coagulation independent of FVIII and FIX. However, its short half-life and high cost have limited its use. One potential solution to this problem may be the use of FVIIa gene transfer, which would attain continuing therapeutic levels of expression from a single injection. The aim of this study was to engineer a novel hFVII (human FVII gene containing a cleavage site for the intracellular protease and furin, by PCR mutagenesis "nMethods: The sequence encoding light and heavy chains of hFVII, were amplified by using hFVII/pTZ57R and specific primers, separately. The PCR products were cloned in pTZ57R vector. "nResults and discussion: Cloning was confirmed by restriction analysis or PCR amplification using specific primers and plasmid universal primers. Mutagenesis of sequence encoding light and heavy chain was confirmed by restriction enzyme. "nConclusion: In the present study, it was provided recombinant plasmids based on mutant form of DNA encoding light and heavy chains.  Joining mutant form of DNA encoding light chain with mutant heavy chain led to a new variant of hFVII. This variant can be activated by furin and an increase in the proportion of activated form of FVII. This mutant form of hFVII may be used for gene therapy of hemophilia.

Artifact suppression in electron paramagnetic resonance imaging of 14N- and 15N-labeled nitroxyl radicals with asymmetric absorption spectra

Science.gov (United States)

Takahashi, Wataru; Miyake, Yusuke; Hirata, Hiroshi

2014-10-01

This article describes an improved method for suppressing image artifacts in the visualization of 14N- and 15N-labeled nitroxyl radicals in a single image scan using electron paramagnetic resonance (EPR). The purpose of this work was to solve the problem of asymmetric EPR absorption spectra in spectral processing. A hybrid function of Gaussian and Lorentzian lineshapes was used to perform spectral line-fitting to successfully separate the two kinds of nitroxyl radicals. This approach can process the asymmetric EPR absorption spectra of the nitroxyl radicals being measured, and can suppress image artifacts due to spectral asymmetry. With this improved visualization method and a 750-MHz continuous-wave EPR imager, a temporal change in the distributions of a two-phase paraffin oil and water/glycerin solution system was visualized using lipophilic and hydrophilic nitroxyl radicals, i.e., 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxy (16-DOXYL stearic acid) and 4-hydroxyl-2,2,6,6-tetramethylpiperidine-d17-1-15N-1-oxyl (TEMPOL-d17-15N). The results of the two-phase separation experiment verified that reasonable artifact suppression could be achieved by the present method that deals with asymmetric absorption spectra in the EPR imaging of 14N- and 15N-labeled nitroxyl radicals.

Graphene-Fiber-Based Supercapacitors Favor N-Methyl-2-pyrrolidone/Ethyl Acetate as the Spinning Solvent/Coagulant Combination.

Science.gov (United States)

He, Nanfei; Pan, Qin; Liu, Yixin; Gao, Wei

2017-07-26

One-dimensional flexible fiber supercapacitors (FSCs) have attracted great interest as promising energy-storage units that can be seamlessly incorporated into textiles via weaving, knitting, or braiding. The major challenges in this field are to develop tougher and more efficient FSCs with a relatively easy and scalable process. Here, we demonstrate a wet-spinning process to produce graphene oxide (GO) fibers from GO dispersions in N-methyl-2-pyrrolidone (NMP), with ethyl acetate as the coagulant. Upon chemical reduction of GO, the resulting NMP-based reduced GO (rGO) fibers (rGO@NMP-Fs) are twice as high in the surface area and toughness but comparable in tensile strength and conductivity as that of the water-based rGO fibers (rGO@H 2 O-Fs). When assembled into parallel FSCs, rGO@NMP-F-based supercapacitors (rGO@NMP-FSCs) offered a specific capacitance of 196.7 F cm -3 (147.5 mF cm -2 ), five times higher than that of rGO@H 2 O-F-based supercapacitors (rGO@H 2 O-FSCs) and also higher than most existing wet-spun rGO-FSCs, as well as those FSCs built with metal wires, graphene/carbon nanotube (CNT) fibers, or even pseudocapacitive materials. In addition, our rGO@NMP-FSCs can provide good bending and cycling stability. The energy density of our rGO@NMP-FSCs reaches ca. 6.8 mWh cm -3 , comparable to that of a Li thin-film battery (4 V/500 μAh).

Development of thermosensitive poly(n-isopropylacrylamide-co-((2-dimethylamino) ethyl methacrylate))-based nanoparticles for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Peng, Cheng-Liang; Luo, Tsai-Yueh; Lin, Wuu-Jyh [Isotope Application Division, Institute of Nuclear Energy Research, PO Box 3-27, Longtan Taoyuan 325, Taiwan (China); Tsai, Han-Min; Yang, Shu-Jyuan; Lin, Chia-Fu; Shieh, Ming-Jium, E-mail: soloman@ntu.edu.tw [Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, No 1, Section 1, Jen-Ai Road, Taipei 10051, Taiwan (China)

2011-07-01

Thermosensitive nanoparticles based on poly(N-isopropylacrylamide-co-((2-dimethylamino)ethylmethacrylate)) (poly(NIPA-co-DMAEMA)) copolymers were successfully fabricated by free radical polymerization. The lower critical solution temperature (LCST) of the synthesized nanoparticles was 41 deg. C and a temperature above which would cause the nanoparticles to undergo a volume phase transition from 140 to 100 nm, which could result in the expulsion of encapsulated drugs. Therefore, we used the poly(NIPA-co-DMAEMA) nanoparticles as a carrier for the controlled release of a hydrophobic anticancer agent, 7-ethyl-10-hydroxy-camptothecin (SN-38). The encapsulation efficiency and loading content of SN-38-loaded nanoparticles at an SN-38/poly(NIPA-co-DMAEMA) ratio of 1/10 (D/P = 1/10) were about 80% and 6.293%, respectively. Moreover, the release profile of SN-38-loaded nanoparticles revealed that the release rate at 42 deg. C (above LCST) was higher than that at 37 deg. C (below LCST), which demonstrated that the release of SN-38 could be controlled by increasing the temperature. The cytotoxicity of the SN-38-loaded poly(NIPA-co-DMAEMA) nanoparticles was investigated in human colon cancer cells (HT-29) to compare with the treatment of an anticancer drug, Irinotecan (CPT-11). The antitumor efficacy evaluated in a C26 murine colon tumor model showed that the SN-38-loaded nanoparticles in combination with hyperthermia therapy efficiently suppressed tumor growth. The results indicate that these thermo-responsive nanoparticles are potential carriers for controlled drug delivery.

ENU mutagenesis to generate genetically modified rat models

NARCIS (Netherlands)

van Boxtel, R.; Gould, M.; Cuppen, E.; Smits, B.M.

2010-01-01

The rat is one of the most preferred model organisms in biomedical research and has been extremely useful for linking physiology and pathology to the genome. However, approaches to genetically modify specific genes in the rat germ line remain relatively scarce. To date, the most efficient approach

Damaging Effect of Low Energy N+ Implantation on Aspergillus niger Spores

International Nuclear Information System (INIS)

Wang Lisheng; Cai Kezhou; Cheng Maoji; Chen Lijuan; Liu Xuelan; Zhang Shuqing; Yu Zengliang

2007-01-01

The mutant effects of a keV range nitrogen ion (N + ) beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance (ESR) results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope (SEM). The mutagenic effect on genome indicated that N + implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms

Iron halide mediated atom transfer radical polymerization of methyl methacrylate with N-Alkyl-2-pyridylmethanimine as the ligand

NARCIS (Netherlands)

Zhang, H.; Schubert, U.S.

2004-01-01

The controlled atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) catalyzed by iron halide/N-(n-hexyl)-2-pyridylmethanimine (NHPMI) is described. The ethyl 2-bromoisobutyrate (EBIB)-initiated ATRP with [MMA]0/[EBIB]0/[iron halide]0/[NHPMI]0 = 150/1/1/2 was better controlled in

Voltammetric oxidation of Hantzsch 1,4-dihydropyridines in protic and aprotic media: relevance of the substitution on N position

International Nuclear Information System (INIS)

Lopez-Alarcon, C.; Nunez-Vergara, L.J.; Squella, J.A.

2003-01-01

A detailed investigation on the electrochemical oxidation of some Hantzsch 1,4-dihydropyridine derivatives with the aim of study the influence of the hydrogen substituent on the N1 position of the heterocyclic ring have been carried out in protic and aprotic media. For this objective we have synthesized two series of compounds wherein the difference was the substituent (H or ethyl) on the N1-position of the heterocyclic ring. Voltammetry, UV-Vis spectroscopy, Controlled potential electrolysis, EPR, 1 H NMR and gas chromatography-mass spectrometry techniques in order to obtain evidences for postulate oxidation mechanisms in both protic and aprotic media have been used. Compounds having the ethyl substituent in the N1 position follow an oxidation mechanism obeying the sequence ECE with the second step as the r.d.e. in both, protic and aprotic media, thus producing the corresponding ethyl substituted pyridinium cation. On the other hand compounds having H in the N1 position follow the same ECE sequence only at acidic media. At basic media, the mechanism consisted of a DISP1 scheme in which rate determining step (r.d.s.) is the uptake of the proton in the N1 position by the OH - ion of the media. In aprotic media both type of compounds follow the same ECEC mechanism with the second step as the r.d.s. but only the H-substituted compounds generates an anionic species that is more easily oxidized than the parent compounds

An inducible tool for random mutagenesis in Aspergillus niger based on the transposon Vader.

Science.gov (United States)

Paun, Linda; Nitsche, Benjamin; Homan, Tim; Ram, Arthur F; Kempken, Frank

2016-07-01

The ascomycete Aspergillus niger is widely used in the biotechnology, for instance in producing most of the world's citric acid. It is also known as a major food and feed contaminant. While generation of gene knockouts for functional genomics has become feasible in ku70 mutants, analyzing gene functions or metabolic pathways remains a laborious task. An unbiased transposon-based mutagenesis approach may aid this process of analyzing gene functions by providing mutant libraries in a short time. The Vader transposon is a non-autonomous DNA-transposon, which is activated by the homologous tan1-transposase. However, in the most commonly used lab strain of A. niger (N400 strain and derivatives), we found that the transposase, encoded by the tan1 gene, is mutated and inactive. To establish a Vader transposon-based mutagenesis system in the N400 background, we expressed the functional transposase of A. niger strain CBS 513.88 under the control of an inducible promoter based on the Tet-on system, which is activated in the presence of the antibiotic doxycycline (DOX). Increasing amounts of doxycycline lead to higher Vader excision frequencies, whereas little to none activity of Vader was observed without addition of doxycycline. Hence, this system appears to be suitable for producing stable mutants in the A. niger N400 background.

System-dependent regulations of colour-pattern development: a mutagenesis study of the pale grass blue butterfly

Science.gov (United States)

Iwata, Masaki; Hiyama, Atsuki; Otaki, Joji M.

2013-01-01

Developmental studies on wing colour patterns have been performed in nymphalid butterflies, but efficient genetic manipulations, including mutagenesis, have not been well established. Here, we have performed mutagenesis experiments in a lycaenid butterfly, the pale grass blue Zizeeria maha, to produce colour-pattern mutants. We fed the P-generation larvae an artificial diet containing the mutagen ethyl methane sulfonate (EMS), and the F1- and F2-generation adults showed various aberrant colour patterns: dorsoventral transformation, anterioposterior background colouration gap, weak contrast, disarrangement of spots, reduction of the size of spots, loss of spots, fusion of spots, and ectopic spots. Among them, the disarrangement, reduction, and loss of spots were likely produced by the coordinated changes of many spots of a single wing around the discal spot in a system-dependent manner, demonstrating the existence of the central symmetry system. The present study revealed multiple genetic regulations for system-dependent and wing-wide colour-pattern determination in lycaenid butterflies. PMID:23917124

Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide using DFT-D calculations and {sup 13}C solid-state NMR

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaozhou; Bond, Andrew D.; Johansson, Kristoffer E.; Van de Streek, Jacco, E-mail: jacco.vandestreek@sund.ku.dk [Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100 (Denmark)

2014-08-01

The crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide contains an imine tautomer, rather than the previously reported amine tautomer. The tautomers can be distinguished using dispersion-corrected density functional theory calculations and by comparison of calculated and measured {sup 13}C solid-state NMR spectra. The crystal structure of the title compound, C{sub 11}H{sub 13}N{sub 3}O{sub 2}S{sub 2}, has been determined previously on the basis of refinement against laboratory powder X-ray diffraction (PXRD) data, supported by comparison of measured and calculated {sup 13}C solid-state NMR spectra [Hangan et al. (2010 ▶). Acta Cryst. B66, 615–621]. The mol@@ecule is tautomeric, and was reported as an amine tautomer [systematic name: N-(5-ethyl-1,3,4-thia@@diazol-2-yl)-p-toluene@@sulfonamide], rather than the correct imine tautomer. The protonation site on the mol@@ecule’s 1,3,4-thia@@diazole ring is indicated by the inter@@molecular contacts in the crystal structure: N—H⋯O hydrogen bonds are established at the correct site, while the alternative protonation site does not establish any notable inter molecular inter@@actions. The two tautomers provide essentially identical Rietveld fits to laboratory PXRD data, and therefore they cannot be directly distinguished in this way. However, the correct tautomer can be distinguished from the incorrect one by previously reported qu@@anti@@tative criteria based on the extent of structural distortion on optimization of the crystal structure using dispersion-corrected density functional theory (DFT-D) calculations. Calculation of the {sup 13}C SS-NMR spectrum based on the correct imine tautomer also provides considerably better agreement with the measured {sup 13}C SS-NMR spectrum.

Ternary liquid-liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

NARCIS (Netherlands)

Meindersma, G.W.; Podt, J.G.; de Haan, A.B.

2006-01-01

This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate

Halogen effect on structure and ¹³C NMR chemical shift of 3,6-disubstituted-N-alkyl carbazoles

DEFF Research Database (Denmark)

Radula-Janik, Klaudia; Kupka, Teobald; Ejsmont, Krzysztof

2013-01-01

Structures of selected 3,6-dihalogeno-N-alkyl carbazole derivatives were calculated at the B3LYP/6-311++G(3df,2pd) level of theory and their 13C NMR isotropic nuclear shieldings were predicted using density functional theory (DFT). The model compounds contained 9H-, N-methyl and N-ethyl derivatives...

Specificity of N-terminal methionyl peptidase: analysis by site-directed mutagenesis

International Nuclear Information System (INIS)

Kasper, T.J.; Boissel, J.P.; Bunn, H.F.

1987-01-01

The start site of eukaryotic translation is normally an AUG codon. The corresponding N-terminal methionine is most often removed when the nascent chain reaches about 30 residues. Data from a survey of 1764 eukaryotic protein sequences suggest that the residue adjacent to the initiator Met determines Met cleavage. In order to investigate the mechanism of this reaction, the authors have prepared oligonucleotide-directed mutants of human β-globin from gapped heteroduplexes of a T3/T7 plasmid containing a globin cDNA clone. To date, the authors have produced mutants encoding for 15 of 19 possible amino acid replacements at position 1 in the β-globin chain. These mutants have been confirmed by dideoxy sequencing, transcribed in vitro, and translated in a rabbit reticulocyte lysate in the presence of 35 S-methionine. Labeled translation products were then isolated by cation exchange HPLC, and tryptic peptides were analyzed by RP-HPLC. Thus far, this structural analysis has shown that for β-1 Val, Ala, and Ser, the initiator Met is cleaved, whereas for β-1 Lys, Met, Glu, Trp, Asn, Tyr, and Glu, initiator Met is retained. For β-1 Leu initiator Met is cleaved with a frequency of about 50%. These results are consistent with the data obtained from the previous survey. The expression of site-directed mutants in a cell-free system can also be used to investigate other N-terminal processing events, such as acetylation and myristylation

[(Z-O-Ethyl N-(4-nitrophenylthiocarbamato-κS](triethylphosphine-κPgold(I

Directory of Open Access Journals (Sweden)

Soo Yei Ho

2009-11-01

Full Text Available In the title compound, [Au(C9H9N2O3S(C6H15P], two virtually identical molecules comprise the asymmetric unit. These are connected by Au...Au [3.6796 (4 Å] and Au...S [3.6325 (18 and 3.5471 (18 Å] contacts, forming a dimeric aggregate. The presence of intramolecular Au...O contacts [2.993 (5 and 2.957 (5 Å] is responsible for the slight deviations from the ideal linear coordination environments about the AuI ions. The conformation about the central C=N double bond is Z. Supramolecular chains sustained by π–π [3.573 (4 Å] and C—H...π interactions are evident in the crystal structure. These are connected into layers via weak intermolecular C—H...O interactions involving the nitro-group O atoms.

Carcinogenicity of 1-methyl-3(p-chlorophenyl)-1-nitrosourea and its 1-methyl trideuterated derivative in rats.

Science.gov (United States)

Schreiber, D; Martin, J; Mendel, J

1986-01-01

The carcinogenic activity of 1-methyl-3(p-chlorophenyl)-1-nitrosourea (Cl-MPNU) and its 1-methyl trideuterated analog (Cl-MPNU-d3) was compared by intragastric administration to hooded rats of equimolar doses of both compounds. A 100% frequency of forestomach tumors was observed in both groups. However, the mean latency period of the animals treated with Cl-MPNU-d3 was significantly longer (P less than 0.01). The results suggest the occurrence of a deuterium isotope effect in nitrosoureas but not as distinct as in nitrosamines.

Synthesis of New Functionalized Indoles Based on Ethyl Indol-2-carboxylate

Directory of Open Access Journals (Sweden)

Ahmed T. A. Boraei

2016-03-01

Full Text Available Successful alkylations of the nitrogen of ethyl indol-2-carboxylate were carried out using aq. KOH in acetone. The respective N-alkylated acids could be obtained without separating the N-alkylated esters by increasing the amount of KOH and water. The use of NaOMe in methanol led to transesterification instead of the alkylation, while the use of NaOEt led to low yields of the N-alkylated acids. Hydrazinolysis of the ester gave indol-2-carbohydrazide which then was allowed to react with different aromatic aldehydes and ketones in ethanol catalyzed by acetic acid. Indol-2-thiosemicarbazide was used in a heterocyclization reaction to form thiazoles. The new structures were confirmed using NMR, mass spectrometry and X-ray single crystal analysis.

N-terminal tetrapeptide T/SPLH motifs contribute to multimodal activation of human TRPA1 channel

Czech Academy of Sciences Publication Activity Database

Hynková, Anna; Maršáková, Lenka; Vašková, Jana; Vlachová, Viktorie

2016-01-01

Roč. 6, Jun 27 (2016), s. 28700 ISSN 2045-2322 R&D Projects: GA ČR(CZ) GA15-15839S Institutional support: RVO:67985823 Keywords : ankyrin receptor subtype 1 * transient receptor potential * gating * ankyrin repeat * whole-cell electrophysiology * N-terminus * mutagenesis Subject RIV: FH - Neurology Impact factor: 4.259, year: 2016

Synthesis of triated N1'-alkyl derivatives of the delta opioid receptor ligand naltrindole

International Nuclear Information System (INIS)

Lever, J.R.; Johnson, S.M.

1997-01-01

Tritiated N1'-methyl and N1'-ethyl analogues of naltrindole (NTI) have been synthesized for evaluation as radioligands for studies of delta opioid receptors. The two N1'-alkyl-5',7'-dibromoNTI precursors for radiolabeling were prepared by base-promoted alkylation of 2,4-dibromophenylhydrazine with either iodomethane or iodoethane followed by condensation with naltrexone using the Fischer indole synthesis. Catalytic debromotritiation followed by HPLC purification afforded [ 3 H]MeNTI (17.3 Ci/mmol) and [ 3 H]EtNTI (22.5 Ci/mmol) with high chemical and radiochemical purities (≥ 99.8%). (author)

Crystal structure, solvothermal synthesis, thermogravimetric studies and DFT calculations of a five-coordinate cobalt(II) compound based on the N,N-bis-(2-hy-droxy-eth-yl)glycine anion.

Science.gov (United States)

Zhou, Yanling; Liu, Xianrong; Wang, Qijun; Wang, Lisheng; Song, Baoling

2016-10-01

The reaction of CoCl 2 ·6H 2 O, N , N -bis-(2-hy-droxy-eth-yl)glycine and tri-ethyl-amine (Et 3 N) in ethanol solution under solvothermal conditions produced crystals of [ N , N -bis-(2-hy-droxy-eth-yl)glycinato]chloridocobalt(II), [Co(C 6 H 12 NO 4 )Cl]. The Co II ion is coordinated in a slightly distorted trigonal-bipyramidal environment which is defined by three O atoms occupying the equatorial plane and the N and Cl atoms in the apical sites. In the crystal, two types of O-H⋯O hydrogen bonds connect the mol-ecules, forming a two-dimensional network parallel to (001). The mol-ecular structure of the title compound confirms the findings of FTIR, elemental analysis, ESI-MS analysis and TG analysis. By using the density functional theory (DFT) (B3LYP) method with 6-31G(d) basis set, the molecular structure has been calculated and optimized.

One-pot Synthesis of Substituted Pyrroles with N,N,N',N'

African Journals Online (AJOL)

In this research, N,N,N'N'-tetrachlorobenzene-1,3-disulphonamide as novel catalytic reagent and N,N'-diiodo-N,N'-1,2-ethanediylbis(p-toluenesulphonamide) as new catalyst were used for the synthesis of N-substituted pyrroles in good to excellent yields under mild conditions. These reusable reagents were compared with ...

Bis(O-ethyl dithio-carbonato-κS,S')bis-(pyridine-3-carbonitrile-κN)nickel(II).

Science.gov (United States)

Kapoor, Sanjay; Kour, Ramandeep; Sachar, Renu; Kant, Rajni; Gupta, Vivek K; Kapoor, Kamini

2012-01-01

The Ni(2+) ion in the title complex, [Ni(C(3)H(5)OS(2))(2)(C(6)H(4)N(2))(2)], is in a strongly distorted octa-hedral coordination environment formed by an N(2)S(4) donor set, with the Ni(2+) ion located on a centre of inversion. In the crystal, weak C-H⋯S and C-H⋯N inter-actions are observed.

Antiviral and Virucidal Activities of N-Cocoyl-L-Arginine Ethyl Ester

Directory of Open Access Journals (Sweden)

Hisashi Yamasaki

2011-01-01

Full Text Available Various amino acid-derived compounds, for example, Nα-Cocoyl-L-arginine ethyl ester (CAE, alkyloxyhydroxylpropylarginine, arginine cocoate, and cocoyl glycine potassium salt (Amilite, were examined for their virucidal activities against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2, influenza A virus (IAV, and poliovirus type 1 (PV-1 in comparison to benzalkonium chloride (BKC and sodium dodecylsulfate (SDS as a cationic and anionic control detergent and also to other commercially available disinfectants. While these amino acid-derived compounds were all effective against HSV-1 and HSV-2, CAE and Amilite were the most effective. These two compounds were, however, not as effective against IAV, another enveloped virus, as against HSV. Cytotoxicity of CAE was weak; at 0.012%, only 5% of the cells were killed under the conditions, in which 100% cells were killed by either SDS or BKC. In addition to these direct virucidal effects, CAE inhibited the virus growth in the HSV-1- or PV-1-infected cells even at 0.01%. These results suggest a potential application of CAE as a therapeutic or preventive medicine against HSV superficial infection at body surface.

Adsorption of acetanilide herbicides on soil and its components. II. Adsorption and catalytic hydrolysis of diethatyl-ethyl on saturated Na(+)-, K(+)-, Ca(2+)-, and Mg(2+)-montmorillonite.

Science.gov (United States)

Liu, W P; Fang, Z; Liu, H J; Yang, W C

2001-04-01

Adsorption and catalytic hydrolysis of the herbicide diethatyl-ethyl [N-chloroacetyl-N-(2,6-diethylphenyl)glycine ethyl ester] on homoionic Na(+)-, K(+)-, Ca(2+)-, and Mg(2+)-montmorillonite clays were investigated in water solution. The Freundlich adsorption coefficient, Ki, got from isotherms on clay followed the order of Na+ approximately K+ > Mg2+ approximately Ca2+. Analysis of FT-IR spectra of diethatyl-ethyl adsorbed on clay suggests probable bonding at the carboxyl and amide carbonyl groups of the herbicide. The rate of herbicide hydrolysis in homoionic clay suspensions followed the same order as that for adsorption, indicating that adsorption may have preceded and thus caused hydrolysis. Preliminary product identification showed that hydrolysis occurred via nucleophilic substitution at the carboxyl carbon, causing the cleavage of the ester bond and formation of diethatyl and its dechlorinated derivative, and at the amide carbon, yielding an ethyl ester derivative and its acid. These pathways also suggest that hydrolysis of diethatyl-ethyl was catalyzed by adsorption on the clay surface.

Role Of Shark Cartilage In Reducing Changes In Gene Expression Of Some Enzymes Induced By N-Nitroso-N-Methyl Urea In Prostate Of Irradiated Rats

International Nuclear Information System (INIS)

ELMAGHRABY, T.; YACOUB, S.; IBRAHIM, N.K.

2009-01-01

There is overwhelming evidence to indicate that free radicals cause oxidative damage to lipids, proteins and nucleic acids and are involved in the pathogenesis of several diseases. Therefore, antioxidants, which can neutralize free radicals, may be of central importance in the prevention of these diseases. Recent studies demonstrated the role of shark cartilage in protecting cells against reactive oxygen species induced DNA damage and mutagenesis. Reactive oxygen species and other free radicals are known to be the mediators of phenotypic and genotypic changes that lead from mutation to neoplasia. There are some primary antioxidants such as glutathione peroxidase (GSHPx), glutathione-S-transferase (GST-π) and super oxide dismutase (SOD), which protects against cellular and molecular damage caused by the reactive oxygen metabolites (ROMs).In this study, the effect of shark cartilage against the N-nitroso-N-methyl urea + testosterone and/or gamma radiation-induced mutagens and carcinogens in rat prostate were investigated.The data showed significant decrease in gene expression of manganese superoxide dismutase (Mn-SOD), glutathione peroxidase 1 (GSHPx1) , enzyme activities of total superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) and non-significant increase in glutathione-S-transferase (GST-π) in N-nitroso-N-methyl urea + testosterone, N-nitroso-N-methyl urea + testosterone + gamma radiation groups as compared to control group.The results revealed that shark cartilage administration afford a significant protective effect against N-nitroso-N-methyl urea + testosterone and/or gamma radiation- induced oxidative injury.

Sensitive radioimmunoassay for detection of O6-ethyldeoxyguanosine in DNA exposed to the carcinogen ethylnitrosourea in vivo or in vitro

International Nuclear Information System (INIS)

Mueller, R.; Rajewsky, M.F.

1978-01-01

O 6 -ethyl-2'-deoxyguanosine (O 6 -EtdGuo) is a major premutational product formed in both intracellular DNA and in purified DNA in vitro, after exposure to the potent alkylating carcinogen N-ethyl-N-nitrosourea (EtNU). Antibodies directed against O 6 -EtdGuo were obtained by immunizing rabbits with a conjungate of O 6 -EtGuo and bovine serum albumin. In a competitive radioimmunoassay (RIA), with O 6 -Et(8,5' 3 H)dGuo as a tracer and various alkylated and natural nucleic acid components as inhibitors, these antibodies show high specificity for O 6 -EtdGuo and detect this product at a level of 0.3 picomol (antibody association constant, 7x10 8 l/mol). In a sample of 130 μg of hydrolyzed DNA, O 6 -EtdGuo can thus be measured at a molar ratio of O 6 -EtdGuo/2'-deoxyguanosine of about 3x10 -6 , i. e., about 5X10 3 O 6 -EtdGuo molecules per diploid cell. Examples are given for the quantitation of O 6 -EtdGuo in DNA exposed to EtNU in vivo or in vitro. (orig.) [de

The relationship between reaction kinetics and mutagenic action of monofunctional alkylating agents in higher eukaryotic systems. IV. The effects of the excision-defective mei-9L1 and mus(2)201D1 mutants on alkylation-induced genetic damage in Drosophila.

Science.gov (United States)

Vogel, E W; Dusenbery, R L; Smith, P D

1985-04-01

Repair-defective mutants of Drosophila melanogaster which identify two major DNA excision repair loci have been examined for their effects on alkylation-induced mutagenesis using the sex-linked recessive lethal assay as a measure of genotoxic endpoint. The alkylating agents (AAs) chosen for comparative analysis were selected on the basis of their reaction kinetics with DNA and included MMS, EMS, MNU, DMN, ENU, DEN and ENNG. Repair-proficient males were treated with the AAs and mated with either excision-defective mei-9L1 or mus(2)201D1 females or appropriate excision-proficient control females. The results of the present work suggest that a qualitative and quantitative relationship exists between the nature and the extent of chemical modification of DNA and the induction of of genetic alterations. The presence of either excision-defective mutant can enhance the frequency of mutation (hypermutability) and this hypermutability can be correlated with the Swain-Scott constant S of specific AAs such that as the SN1 character of the DNA alkylation reaction increases, the difference in response between repair-deficient and repair-proficient females decreases. The order of hypermutability of AAs with mei-9L1 relative to mei-9+ is MMS greater than MNU greater than DMN = EMS greater than iPMS = ENU = DEN = ENNG. When the percentage of lethal mutations induced in mei-9L1 females are plotted against those determined for control females, straight lines of different slopes are obtained. These mei-9L1/mei-9+ indices are: MMS = 7.6, MNU = 5.4, DMN = 2.4, EMS = 2.4 and iPMS = ENU = DEN = ENNG = 1. An identical order of hypermutability with similar indices is obtained for the mus(2)201 mutants: MMS(7.3) greater than MNU (5.4) greater than EMS(2.0) greater than ENU(1.1). Thus, absence of excision repair function has a significant effect on mutation production by AAs efficient in alkylating N-atoms in DNA but no measurable influence on mutation production by AAs most efficient in

Poly(ADP-ribose) polymerase-independent potentiation of nitrosourea cytotoxicity by 3-aminobenzamide in human malignant glioma cells.

Science.gov (United States)

Winter, S; Weller, M

2000-06-16

Poly(ADP-ribose) polymerase is a zinc-finger DNA-binding protein that detects specifically DNA strand breaks generated by genotoxic agents and is thought to be involved in DNA repair. Here, we examined the effects of 3-aminobenzamide, a poly(ADP-ribose) polymerase inhibitor, on the chemosensitivity of human malignant glioma cells. 3-Aminobenzamide selectively potentiated the cytotoxicity of the nitrosoureas, nimustine, carmustine and lomustine in 10 of 12 human malignant glioma cell lines. In contrast, 3-aminobenzamide did not modulate the cytotoxic effects of doxorubicine, teniposide, vincristine, camptothecin or cytarabine. The nitrosoureas did not induce poly(ADP-ribose) polymerase activity in the glioma cells. Ectopic expression of truncated poly(ADP-ribose) polymerase containing the poly(ADP-ribose) polymerase DNA-binding domain, which acts as a dominant-negative mutant, in LN-18 or LN-229 cells did not alter the 3-aminobenzamide effect on nitrosourea-mediated cytotoxicity. Thus, 3-aminobenzamide may target another nicotinamide adenine dinucleotide (NAD)-requiring enzyme, but not poly(ADP-ribose) polymerase, when enhancing nitrosourea cytotoxicity in human malignant glioma cells. Carmustine cytotoxicity was associated with a G2/M arrest. Coexposure to carmustine and 3-aminobenzamide overcame this G2/M arrest in T98G cells, which are sensitized to carmustine by 3-aminobenzamide, but not in U251MG cells, which are refractory to 3-aminobenzamide-mediated sensitization to carmustine. Thus, 3-aminobenzamide-mediated sensitization to carmustine cytotoxicity may result from interference with the stable G2/M arrest response to carmustine in human glioma cells.

Quest of novel GH20 N-acetyl hexosaminidasetransglycosylating catalysts: functional screening, data mining and semi-rational mutagenesis

DEFF Research Database (Denmark)

Teze, David; Visnapuu, Triinu; Kjeldsen, Christian

and the fact that the products are also substrates, thus needing a kinetic control of the reaction. Several approaches have been developed to overcome these, including mechanism modifications (e.g. glycosynthases, chemical rescue), functional screening and data mining to find natural transglycosidases...... been reported. Thus, we turned to discovery and characterization of new GH20s and performing a systematic mutagenesis study. Several new GH20s of bacterial origin were isolated and described by functional screening and data mining, including transglycosidases able to synthesize lacto...

Random Mutagenesis of the Aspergillus oryzae Genome Results in Fungal Antibacterial Activity

Directory of Open Access Journals (Sweden)

Cory A. Leonard

2013-01-01

Full Text Available Multidrug-resistant bacteria cause severe infections in hospitals and communities. Development of new drugs to combat resistant microorganisms is needed. Natural products of microbial origin are the source of most currently available antibiotics. We hypothesized that random mutagenesis of Aspergillus oryzae would result in secretion of antibacterial compounds. To address this hypothesis, we developed a screen to identify individual A. oryzae mutants that inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA in vitro. To randomly generate A. oryzae mutant strains, spores were treated with ethyl methanesulfonate (EMS. Over 3000 EMS-treated A. oryzae cultures were tested in the screen, and one isolate, CAL220, exhibited altered morphology and antibacterial activity. Culture supernatant from this isolate showed antibacterial activity against Methicillin-sensitive Staphylococcus aureus, MRSA, and Pseudomonas aeruginosa, but not Klebsiella pneumonia or Proteus vulgaris. The results of this study support our hypothesis and suggest that the screen used is sufficient and appropriate to detect secreted antibacterial fungal compounds resulting from mutagenesis of A. oryzae. Because the genome of A. oryzae has been sequenced and systems are available for genetic transformation of this organism, targeted as well as random mutations may be introduced to facilitate the discovery of novel antibacterial compounds using this system.

Random Mutagenesis of the Aspergillus oryzae Genome Results in Fungal Antibacterial Activity

Science.gov (United States)

Leonard, Cory A.; Brown, Stacy D.; Hayman, J. Russell

2013-01-01

Multidrug-resistant bacteria cause severe infections in hospitals and communities. Development of new drugs to combat resistant microorganisms is needed. Natural products of microbial origin are the source of most currently available antibiotics. We hypothesized that random mutagenesis of Aspergillus oryzae would result in secretion of antibacterial compounds. To address this hypothesis, we developed a screen to identify individual A. oryzae mutants that inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA) in vitro. To randomly generate A. oryzae mutant strains, spores were treated with ethyl methanesulfonate (EMS). Over 3000 EMS-treated A. oryzae cultures were tested in the screen, and one isolate, CAL220, exhibited altered morphology and antibacterial activity. Culture supernatant from this isolate showed antibacterial activity against Methicillin-sensitive Staphylococcus aureus, MRSA, and Pseudomonas aeruginosa, but not Klebsiella pneumonia or Proteus vulgaris. The results of this study support our hypothesis and suggest that the screen used is sufficient and appropriate to detect secreted antibacterial fungal compounds resulting from mutagenesis of A. oryzae. Because the genome of A. oryzae has been sequenced and systems are available for genetic transformation of this organism, targeted as well as random mutations may be introduced to facilitate the discovery of novel antibacterial compounds using this system. PMID:23983696

Random Mutagenesis of the Aspergillus oryzae Genome Results in Fungal Antibacterial Activity.

Science.gov (United States)

Leonard, Cory A; Brown, Stacy D; Hayman, J Russell

2013-01-01

Multidrug-resistant bacteria cause severe infections in hospitals and communities. Development of new drugs to combat resistant microorganisms is needed. Natural products of microbial origin are the source of most currently available antibiotics. We hypothesized that random mutagenesis of Aspergillus oryzae would result in secretion of antibacterial compounds. To address this hypothesis, we developed a screen to identify individual A. oryzae mutants that inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA) in vitro. To randomly generate A. oryzae mutant strains, spores were treated with ethyl methanesulfonate (EMS). Over 3000 EMS-treated A. oryzae cultures were tested in the screen, and one isolate, CAL220, exhibited altered morphology and antibacterial activity. Culture supernatant from this isolate showed antibacterial activity against Methicillin-sensitive Staphylococcus aureus, MRSA, and Pseudomonas aeruginosa, but not Klebsiella pneumonia or Proteus vulgaris. The results of this study support our hypothesis and suggest that the screen used is sufficient and appropriate to detect secreted antibacterial fungal compounds resulting from mutagenesis of A. oryzae. Because the genome of A. oryzae has been sequenced and systems are available for genetic transformation of this organism, targeted as well as random mutations may be introduced to facilitate the discovery of novel antibacterial compounds using this system.

Slp-76 is a critical determinant of NK-cell mediated recognition of missing-self targets.

Science.gov (United States)

Lampe, Kristin; Endale, Mehari; Cashman, Siobhan; Fang, Hao; Mattner, Jochen; Hildeman, David; Hoebe, Kasper

2015-07-01

Absence of MHC class I expression is an important mechanism by which NK cells recognize a variety of target cells, yet the pathways underlying "missing-self" recognition, including the involvement of activating receptors, remain poorly understood. Using ethyl-N-nitrosourea mutagenesis in mice, we identified a germline mutant, designated Ace, with a marked defect in NK cell mediated recognition and elimination of "missing-self" targets. The causative mutation was linked to chromosome 11 and identified as a missense mutation (Thr428Ile) in the SH2 domain of Slp-76-a critical adapter molecule downstream of ITAM-containing surface receptors. The Slp-76 Ace mutation behaved as a hypomorphic allele-while no major defects were observed in conventional T-cell development/function, a marked defect in NK cell mediated elimination of β2-microglobulin (β2M) deficient target cells was observed. Further studies revealed Slp-76 to control NK-cell receptor expression and maturation; however, activation of Slp-76(ace/ace) NK cells through ITAM-containing NK-cell receptors or allogeneic/tumor target cells appeared largely unaffected. Imagestream analysis of the NK-β2M(-/-) target cell synapse revealed a specific defect in actin recruitment to the conjugate synapse in Slp-76(ace/ace) NK cells. Overall these studies establish Slp-76 as a critical determinant of NK-cell development and NK cell mediated elimination of missing-self target cells in mice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tweaking agonist efficacy at N-methyl-D-aspartate receptors by site-directed mutagenesis

DEFF Research Database (Denmark)

Hansen, Kasper B; Clausen, Rasmus P; Bjerrum, Esben J

2005-01-01

The structural basis for partial agonism at N-methyl-D-aspartate (NMDA) receptors is currently unresolved. We have characterized several partial agonists at the NR1/NR2B receptor and investigated the mechanisms underlying their reduced efficacy by introducing mutations in the glutamate binding site...

Rapid NIR determination of alkyl esters in virgin olive oil; Determinación rápida de ésteres alquílicos en aceite de oliva virgen para detección temprana de defectos sensoriales

Energy Technology Data Exchange (ETDEWEB)

Cayuela, J.A.

2017-07-01

The regulation of The European Union for olive oil and olive pomace established the limit of 35 mg·kg-1 for fatty acids ethyl ester contents in extra virgin olive oils, from grinding seasons after 2016. In this work, predictive models have been established for measuring fatty acid ethyl and methyl esters and to measure the total fatty acid alkyl esters based on near infrared spectroscopy (NIRS), and used successfully for this purpose. The correlation coefficients from the external validation exercises carried out with these predictive models ranged from 0.84 to 0.91. Different classification tests using the same models for the thresholds 35 mg·kg-1 for fatty acid ethyl esters and 75 mg·kg-1 for fatty acid alkyl esters provided success percentages from 75.0% to 95.2%. [Spanish] La reglamentación de la Unión Europea para el aceite de oliva y el orujo de oliva ha establecido el límite de 35 mg·kg-1 al contenido de ésteres etílicos de ácidos grasos en los aceites de oliva virgen extra, para campañas de molienda posteriores a 2016. En este trabajo se han establecido modelos predictivos para medir los ésteres etílicos y metílicos de ácidos grasos y para la medida de los ésteres alquílicos de ácidos grasos totales basados en la espectroscopía de infrarrojo cercano (NIRS) y utilizados con éxito para este propósito. Los coeficientes de correlación de los ejercicios de validación externa realizados con estos modelos predictivos oscilaron entre 0,84 y 0,91. Diferentes pruebas de clasificación utilizando los mismos modelos con respecto a los umbrales de 35 mg·kg-1 para ésteres etílicos y 75 mg·kg-1 para ésteres alquílicos, proporcionaron porcentajes de éxito del 75,0% al 95,2%.

Damaging Effect of Low Energy N{sup +} Implantation on Aspergillus niger Spores

Energy Technology Data Exchange (ETDEWEB)

Lisheng, Wang [Department of Animal Science and Technology, Anhui Agricultural University, Hefei 230036 (China); Kezhou, Cai [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Maoji, Cheng [Department of Animal Science and Technology, Anhui Agricultural University, Hefei 230036 (China); Lijuan, Chen [Department of Animal Science and Technology, Anhui Agricultural University, Hefei 230036 (China); Xuelan, Liu [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Shuqing, Zhang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Zengliang, Yu [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China)

2007-06-15

The mutant effects of a keV range nitrogen ion (N{sup +}) beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance (ESR) results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope (SEM). The mutagenic effect on genome indicated that N{sup +} implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms.

Chemical and UV Mutagenesis.

Science.gov (United States)

Bose, Jeffrey L

2016-01-01

The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

Identification and analytical characterization of six synthetic cannabinoids NNL-3, 5F-NPB-22-7N, 5F-AKB-48-7N, 5F-EDMB-PINACA, EMB-FUBINACA, and EG-018.

Science.gov (United States)

Liu, Cuimei; Jia, Wei; Hua, Zhendong; Qian, Zhenhua

2017-08-01

Clinical and forensic toxicology laboratories are continuously confronted by analytical challenges when dealing with the new psychoactive substances phenomenon. The number of synthetic cannabinoids, the chemical diversity, and the speed of emergence make this group of compounds particularly challenging in terms of detection, monitoring, and responding. Three indazole 7N positional isomer synthetic cannabinoids, two ethyl 2-amino-3-methylbutanoate-type synthetic cannabinoids, and one 9H-carbazole substituted synthetic cannabinoid were identified in seized materials. These six synthetic cannabinoid derivatives included: 1H-benzo[d] [1,2,3]triazol-1-yl 1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate (NNL-3, 1), quinolin-8-yl 1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate (5F-NPB-22-7N, 2), N-((1 s,3 s)-adamantan-1-yl)-1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide (5F-AKB-48-7N, 3), ethyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate (5F-EDMB-PINACA, 4), ethyl 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3-methylbutanoate (EMB-FUBINACA, 5), and naphthalen-1-yl(9-pentyl-9H-carbazol-3-yl)methanone (EG-018, 6). The identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance spectroscopy (NMR). The analytical characterization of these six synthetic cannabinoids was described, so as to assist forensic laboratories in identifying these compounds or other substances with similar structure in their case work. To our knowledge, no analytical data about the compounds 1-5 have appeared until now, making this the first report on these compounds. The GC-MS data of 6 has been reported, but this study added the LC-MS, NMR, and Fourier transform infrared (FTIR), data to render the analytical data collection process more complete. Copyright © 2017 John Wiley & Sons, Ltd

Receptor binding profiles and behavioral pharmacology of ring-substituted N,N-diallyltryptamine analogs.

Science.gov (United States)

Klein, Landon M; Cozzi, Nicholas V; Daley, Paul F; Brandt, Simon D; Halberstadt, Adam L

2018-02-27

Substantial effort has been devoted toward understanding the psychopharmacological effects of tryptamine hallucinogens, which are thought to be mediated by activation of 5-HT 2A and 5-HT 1A receptors. Recently, several psychoactive tryptamines based on the N,N-diallyltryptamine (DALT) scaffold have been encountered as recreational drugs. Despite the apparent widespread use of DALT derivatives in humans, little is known about their pharmacological properties. We compared the binding affinities of DALT and its 2-phenyl-, 4-acetoxy-, 4-hydroxy-, 5-methoxy-, 5-methoxy-2-methyl-, 5-fluoro-, 5-fluoro-2-methyl-, 5-bromo-, and 7-ethyl-derivatives at 45 receptor and transporter binding sites. Additionally, studies in C57BL/6 J mice examined whether these substances induce the head twitch response (HTR), a 5-HT 2A receptor-mediated response that is widely used as a behavioral proxy for hallucinogen effects in humans. Most of the test drugs bound to serotonin receptors, σ sites, α 2 -adrenoceptors, dopaminergic D 3 receptors, histaminergic H 1 receptors, and the serotonin transporter. DALT and several of the ring-substituted derivatives were active in the HTR assay with the following rank order of potency: 4-acetoxy-DALT > 5-fluoro-DALT > 5-methoxy-DALT > 4-hydroxy-DALT > DALT > 5-bromo-DALT. 2-Phenyl-DALT, 5-methoxy-2-methyl-DALT, 5-fluoro-2-methyl-DALT, and 7-ethyl-DALT did not induce the HTR. HTR potency was not correlated with either 5-HT 1A or 5-HT 2A receptor binding affinity, but a multiple regression analysis indicated that 5-HT 2A and 5-HT 1A receptors make positive and negative contributions, respectively, to HTR potency (R 2  = 0.8729). In addition to supporting the established role of 5-HT 2A receptors in the HTR, these findings are consistent with evidence that 5-HT 1A activation by tryptamine hallucinogens buffers their effects on HTR. Published by Elsevier Ltd.

Random mutagenesis of aspergillus niger and process optimization for enhanced production of glucose oxidase

International Nuclear Information System (INIS)

Haq, I.; Nawaz, A.; Mukhtar, A.N.H.; Mansoor, H.M.Z.; Ameer, S.M.

2014-01-01

The study deals with the improvement of wild strain Aspergillus niger IIB-31 through random mutagenesis using chemical mutagens. The main aim of the work was to enhance the glucose oxidase (GOX) yield of wild strain (24.57+-0.01 U/g of cell mass) through random mutagenesis and process optimization. The wild strain of Aspergillus niger IIB-31 was treated with chemical mutagens such as Ethyl methane sulphonate (EMS) and nitrous acid for this purpose. Mutagen treated 98 variants indicating the positive results were picked and screened for the glucose oxidase production using submerged fermentation. EMS treated E45 mutant strain gave the highest glucose oxidase production (69.47 + 0.01 U/g of cell mass), which was approximately 3-folds greater than the wild strain IIB-31. The preliminary cultural conditions for the production of glucose oxidase using submerged fermentation from strain E45 were also optimized. The highest yield of GOD was obtained using 8% glucose as carbon and 0.3% peptone as nitrogen source at a medium pH of 7.0 after an incubation period of 72 hrs at 30 degree. (author)

Di-n-butylbis[N-(2-methoxyethyl-N-methyldithiocarbamato-κ2S,S′]tin(IV: crystal structure and Hirshfeld surface analysis

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Rapidah Mohamad

2017-02-01

Full Text Available The complete molecule of the title compound, [Sn(C4H92(C5H10NOS22], is generated by a crystallographic mirror plane, with the SnIV atom and the two inner methylene C atoms of the butyl ligands lying on the mirror plane; statistical disorder is noted in the two terminal ethyl groups, which deviate from mirror symmetry. The dithiocarbamate ligand coordinates to the metal atom in an asymmetric mode with the resulting C2S4 donor set defining a skew trapezoidal bipyramidal geometry; the n-butyl groups are disposed to lie over the longer Sn—S bonds. Supramolecular chains aligned along the a-axis direction and sustained by methylene-C—H...S(weakly coordinating interactions feature in the molecular packing. A Hirshfeld surface analysis reveals the dominance of H...H contacts in the crystal.

[Stress-induced cellular adaptive mutagenesis].

Science.gov (United States)

Zhu, Linjiang; Li, Qi

2014-04-01

The adaptive mutations exist widely in the evolution of cells, such as antibiotic resistance mutations of pathogenic bacteria, adaptive evolution of industrial strains, and cancerization of human somatic cells. However, how these adaptive mutations are generated is still controversial. Based on the mutational analysis models under the nonlethal selection conditions, stress-induced cellular adaptive mutagenesis is proposed as a new evolutionary viewpoint. The hypothetic pathway of stress-induced mutagenesis involves several intracellular physiological responses, including DNA damages caused by accumulation of intracellular toxic chemicals, limitation of DNA MMR (mismatch repair) activity, upregulation of general stress response and activation of SOS response. These responses directly affect the accuracy of DNA replication from a high-fidelity manner to an error-prone one. The state changes of cell physiology significantly increase intracellular mutation rate and recombination activity. In addition, gene transcription under stress condition increases the instability of genome in response to DNA damage, resulting in transcription-associated DNA mutagenesis. In this review, we summarize these two molecular mechanisms of stress-induced mutagenesis and transcription-associated DNA mutagenesis to help better understand the mechanisms of adaptive mutagenesis.

Dominant negative umuD mutations decreasing RecA-mediated cleavage suggest roles for intact UmuD in modulation of SOS mutagenesis

International Nuclear Information System (INIS)

Battista, J.R.; Ohta, Toshihiro; Nohmi, Takehiko; Sun, W.; Walker, G.C.

1990-01-01

The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. The UmuD protein shares homology with a family of proteins that includes LexA and several bacteriophage repressors. UmuD is posttranslationally activated for its role n mutagenesis by a RecA-mediated proteolytic cleavage that yields UmuD'. A set of missense mutants of umuD was isolated and shown to encode mutant UmuD proteins that are deficient in RecA-mediated cleavage in vivo. Most of these mutations are dominant to umuD + with respect to UV mutagenesis yet do not interfere with SOS induction. Although both UmuD and UmuD' form homodimers, the authors provide evidence that they preferentially form heterodimers. The relationship of UmuD to LexA, λ repressor, and other members of the family of proteins is discussed and possible roles intact UmuD in modulating SOS mutagenesis are discussed

Modifying effects of lemongrass essential oil on specific tissue response to the carcinogen N-methyl-N-nitrosurea in female BALB/c mice.

Science.gov (United States)

Bidinotto, Lucas T; Costa, Celso A R A; Costa, Mirtes; Rodrigues, Maria A M; Barbisan, Luís F

2012-02-01

Lemongrass (Cymbopogon citratus Stapf) essential oil has been used worldwide because of its ethnobotanical and medicinal usefulness. Regarding its medicinal usefulness, the present study evaluated the beneficial effects of lemongrass essential oil (LGEO) oral treatment on cell proliferation and apoptosis events and on early development of hyperplastic lesions in the mammary gland, colon, and urinary bladder induced by N-methyl-N-nitrosourea (MNU) in female BALB/c mice. The animals were allocated into three groups: G1, treated with LGEO vehicle for 5 weeks (five times per week); G2, treated with LGEO vehicle as for G1 and MNU (two injections each of 30 mg/kg of body weight at weeks 3 and 5); and G3, treated with LGEO (five times each with 500 mg/kg of body weight per week) and MNU as for G2. Twenty-four hours after the last MNU application, all animals were euthanized, and mammary glands, colon, and urinary bladder were collected for histological and immunohistochemical analysis. LGEO oral treatment significantly changed the indexes of apoptosis and/or cellular proliferation for the tissues analyzed. In particular, the treatment reduced the incidence of hyperplastic lesions and increased apoptosis in mammary epithelial cells. This increment in the apoptosis response may be related to a favorable balance in Bcl-2/Bax immunoreactivity in mammary epithelial cells. These findings indicate that LGEO presented a protective role against early MNU-induced mammary gland alterations in BALB/c mice.

Ethyl 4,6-O-benzylidene-2-deoxy-N-phthalimido-1-thio-β-d-glucopyranoside

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Göran Widmalm

2010-12-01

Full Text Available In the title compound, C23H23NO6S, the plane of the N-phthalimido group makes a dihedral angle of 67.4 (1° with the least square plane of the sugar ring defined by the C2, C3, C5 and O5 atoms using standard glucose nomenclature. The thioethyl group has the exo-anomeric conformation. In the crystal, intermolecular hydrogen bonds involving the hydroxy groups and the carbonyl O atoms of adjacent N-phthalimido groups form chains parallel to the b axis. The chains are further stabilized by C—H...π interactions.

Differential inhibition of the rejoining of x-ray-induced DNA strand breaks in normal and transformed human fibroblasts treated with 1,3-bis(2-chloroethyl)-1-nitrosourea in vitro

International Nuclear Information System (INIS)

Erickson, L.C.; Bradley, M.O.; Kohn, K.W.

1978-01-01

The effects of 1,3-bis(2-chloroethyl)-1-nitrosourea on the rejoining of x-ray-induced DNA strand breaks were examined in normal human fibroblasts (WI-38) and a simian virus 40-transformed derivative (VA-13) with the use of alkaline sucrose sedimentation. 1,3-Bis(2-chloroethyl)-1-nitrosourea was capable of partially inhibiting repair of x-ray-produced DNA strand breaks in both cell types when the drug was added to the culture medium immediately after x-irradiation. However, when 1,3-bis(2-chloroethyl)-1-nitrosourea exposure preceded x-ray by 1 hr, DNA repair was inhibited to a much greater extent than it was when 1,3-bis(2-chloroethyl)-1-nitrosourea followed x-ray. The inhibition of DNA repair by 1,3-bis(2-chloroethyl)-1-nitrosourea appeared to be complete in the transformed VA-13 cells, while only partial inhibition of repair was observed in the normal WI-38 cells

A genetic screen for mutations affecting embryonic development in medaka fish (Oryzias latipes).

Science.gov (United States)

Loosli, F; Köster, R W; Carl, M; Kühnlein, R; Henrich, T; Mücke, M; Krone, A; Wittbrodt, J

2000-10-01

In a pilot screen, we assayed the efficiency of ethylnitrosourea (ENU) as a chemical mutagen to induce mutations that lead to early embryonic and larval lethal phenotypes in the Japanese medaka fish, Oryzias latipes. ENU acts as a very efficient mutagen inducing mutations at high rates in germ cells. Three repeated treatments of male fish in 3 mM ENU for 1 h results in locus specific mutation rates of 1.1-1.95 x10(-3). Mutagenized males were outcrossed to wild type females and the F1 offspring was used to establish F2 families. F2 siblings were intercrossed and the F3 progeny was scored 24, 48 and 72 h after fertilization for morphological alterations affecting eye development. The presented mutant phenotypes were identified using morphological criteria and occur during early developmental stages of medaka. They are stably inherited in a Mendelian fashion. The high efficiency of ENU to induce mutations in this pilot screen indicates that chemical mutagenesis and screening for morphologically visible phenotypes in medaka fish allows the genetic analysis of specific aspects of vertebrate development complementing the screens performed in other vertebrate model systems.

Therapeutic efficacy of the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) against organophosphate intoxication

NARCIS (Netherlands)

Bueters, T.J.H.; Groen, B.; Danhof, M.; IJzerman, A.P.; Helden, H.P.M. van

2002-01-01

The objective of the present study was to investigate whether reduction of central acetylcholine (ACh) accumulation by adenosine receptor agonists could serve as a generic treatment against organophosphate (OP) poisoning. The OPs studied were tabun (O-ethyl-N-dimethylphosphoramidocyanidate), sarin

Studies of Silyl-Transfer Photochemical Reactions of N-[(Trimethylsilyl)alkyl]saccharins

Energy Technology Data Exchange (ETDEWEB)

Cho, Dae Won; Oh, Sun Wha; Park, Hea Jung; Yoon, Ung Chan [Pusan National University, Busan (Korea, Republic of); Kim, Dong Uk [Daegu National University of Education, Daegu (Korea, Republic of); Xue, Jin Ying [Harbin Normal University, Harbin (China); Mariano, Patrick S. [University of New Mexico, Albuquerque (United States)

2010-09-15

Photochemical studies of N-[(trimethylsilyl)alkyl]saccharins were carried out to investigate their photochemical behavior. Depending on the nature of the substrate and the solvent system employed, reactions of these substances can take place by either SET-promoted silyl migration from carbon to either the amide carbonyl or sulfonyl oxygen or by a N-S homolysis route. The results of the current studies show that an azomethine ylide, arising from a SET-promoted silyl migration pathway, is generated in photoreactions of N-[(trimethylsilyl)methyl]saccharin and this intermediate reacts to give various photoproducts depending on the conditions employed. In addition, irradiation of N-[(trimethylsily)ethyl]saccharin produces an excited state that reacts through two pathways, the relative importance is governed by solvent polarity and protic nature. Finally, photoirradiation of N-[(trimethylsilyl)propyl]saccharin in a highly polar solvent system comprised of 35% aqueous MeOH gives rise to formation of a tricyclic pyrrolizidine and saccharin that generated via competitive SET-promoted silyl transfer and γ-hydrogen abstraction pathways.

Studies of Silyl-Transfer Photochemical Reactions of N-[(Trimethylsilyl)alkyl]saccharins

International Nuclear Information System (INIS)

Cho, Dae Won; Oh, Sun Wha; Park, Hea Jung; Yoon, Ung Chan; Kim, Dong Uk; Xue, Jin Ying; Mariano, Patrick S.

2010-01-01

Photochemical studies of N-[(trimethylsilyl)alkyl]saccharins were carried out to investigate their photochemical behavior. Depending on the nature of the substrate and the solvent system employed, reactions of these substances can take place by either SET-promoted silyl migration from carbon to either the amide carbonyl or sulfonyl oxygen or by a N-S homolysis route. The results of the current studies show that an azomethine ylide, arising from a SET-promoted silyl migration pathway, is generated in photoreactions of N-[(trimethylsilyl)methyl]saccharin and this intermediate reacts to give various photoproducts depending on the conditions employed. In addition, irradiation of N-[(trimethylsily)ethyl]saccharin produces an excited state that reacts through two pathways, the relative importance is governed by solvent polarity and protic nature. Finally, photoirradiation of N-[(trimethylsilyl)propyl]saccharin in a highly polar solvent system comprised of 35% aqueous MeOH gives rise to formation of a tricyclic pyrrolizidine and saccharin that generated via competitive SET-promoted silyl transfer and γ-hydrogen abstraction pathways

[Retrospective analysis of 24 recurrent glioblastoma after chemoradiation and treated with nitrosoureas or irinotecan and bevacizumab].

Science.gov (United States)

Vauleon, Elodie; Mesbah, Habiba; Gedouin, Daniel; Lecouillard, Isabelle; Louvel, Guillaume; Hamlat, Abderrahmane; Riffaud, Laurent; Carsin, Béatrice; Quillien, Véronique; Audrain, Odile; Lesimple, Thierry

2012-02-01

Despite progress in the initial management of glioblastoma (GB), the vast majority of patients will experience recurrence within 2-3 years. The medical treatment of these recurrences is being modified by the use of antiangiogenic therapies. Twenty-four patients, who relapsed from GB after chemoradiation followed by adjuvant temozolomide in Rennes, were treated by conventional chemotherapy (nitrosourea) or by the combination of irinotecan and bevacizumab. In this retrospective analysis, overall survival from diagnosis of recurrence was significantly longer in patients treated with the combination of bevacizumab and irinotecan than with nitrosourea (5 months versus 11.5 months). The combination of irinotecan and bevacizumab appeared to provide clinical benefit to patients with recurrent GB.

N,N'-Diethyl-N,N'-diphenylpyridine-2,6-dicarboxamide

Czech Academy of Sciences Publication Activity Database

Klepetářová, Blanka; Makrlík, E.; Babain, V.A.; Kašička, Václav

2012-01-01

Roč. 68, č. 4 (2012), o1099-o1100 ISSN 1600-5368 Grant - others:GA ČZU(CZ) 42900/1312/3114 Institutional research plan: CEZ:AV0Z40550506 Keywords : N,N'-Diethyl-N,N'-diphenylpyridine-2,6-dicarboxamide * crystal structure * amide nitrogen Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.347, year: 2011

Mutagenicity studies with the mouse spot test

Energy Technology Data Exchange (ETDEWEB)

Gocke, E.; Wild, D.; Eckhardt, K.; King, M.T.

1983-04-01

The mammalian spot test, which detects somatic gene mutations in mouse embryos, was investigated with selected chemicals to (a) further validate this test system ethylnitrosourea, ethyl methanesulfonate, 2-acetylaminofluorene and colchicine (ENU, EMS, 2AAF), and (b) evaluate the mutagenic potential, in a whole-mammal system, of environmental compounds that had been previously recognized as mutagens in other mammalian or submammalian test systems (1,2-dichloroethane, hydroquinone, nitrofurantoin, o-phenylenediamine, fried sausage extract). Of these substances, ENU, EMS and 2AAF were significantly mutagenic, 1,2-dichloroethane was probably weakly mutagenic. The ENU data were used to estimate the number of pigment precursor cells present at the time of treatment (day 9.25). We also describe in this report the use of a fluorescence microscope for classification of hairs from spots on the coat of C57BL/6JHan X T hybrids.

Comprehensive functional analysis of N-linked glycans on Ebola virus GP1.

Science.gov (United States)

Lennemann, Nicholas J; Rhein, Bethany A; Ndungo, Esther; Chandran, Kartik; Qiu, Xiangguo; Maury, Wendy

2014-01-28

Ebola virus (EBOV) entry requires the virion surface-associated glycoprotein (GP) that is composed of a trimer of heterodimers (GP1/GP2). The GP1 subunit contains two heavily glycosylated domains, the glycan cap and the mucin-like domain (MLD). The glycan cap contains only N-linked glycans, whereas the MLD contains both N- and O-linked glycans. Site-directed mutagenesis was performed on EBOV GP1 to systematically disrupt N-linked glycan sites to gain an understanding of their role in GP structure and function. All 15 N-glycosylation sites of EBOV GP1 could be removed without compromising the expression of GP. The loss of these 15 glycosylation sites significantly enhanced pseudovirion transduction in Vero cells, which correlated with an increase in protease sensitivity. Interestingly, exposing the receptor-binding domain (RBD) by removing the glycan shield did not allow interaction with the endosomal receptor, NPC1, indicating that the glycan cap/MLD domains mask RBD residues required for binding. The effects of the loss of GP1 N-linked glycans on Ca(2+)-dependent (C-type) lectin (CLEC)-dependent transduction were complex, and the effect was unique for each of the CLECs tested. Surprisingly, EBOV entry into murine peritoneal macrophages was independent of GP1 N-glycans, suggesting that CLEC-GP1 N-glycan interactions are not required for entry into this important primary cell. Finally, the removal of all GP1 N-glycans outside the MLD enhanced antiserum and antibody sensitivity. In total, our results provide evidence that the conserved N-linked glycans on the EBOV GP1 core protect GP from antibody neutralization despite the negative impact the glycans have on viral entry efficiency. Filovirus outbreaks occur sporadically throughout central Africa, causing high fatality rates among the general public and health care workers. These unpredictable hemorrhagic fever outbreaks are caused by multiple species of Ebola viruses, as well as Marburg virus. While filovirus

Expression of Two N1 Clones with Single Amino Acid Dissimilarity of Avian Influenza H5N1 Virus

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RISZA HARTAWAN

2012-12-01

Full Text Available Two clones of N1 gene derived from isolate A/Dk/Tangerang/Bbalitvet-ACIAR-TE11/2007 (H5N1 exhibit single mismatch of amino acid sequence at position 242 that is threonine and methionine for the clone #3 and #5, respectively. In order to evaluate the effect of the amino acid substitution, these clones were inserted into two different expression vectors that are pEGFP-C1 and pcDNA-3.3 TOPO® TA cloning. Subsequently, the respective recombinant clones were transfected into eukaryotic cells, including CEF, RK13 and VERO using Lipofectamine ‘plus’ reagent. As a result, the clone #3 retaining atypical sequence showed lower expression level rather than the clone #15 in both vectors and all type of cells. The 3D conformational modelling revealed that the mutation occurs in the inner part of glycoprotein embedded within envelope or matrix. Therefore, the missense mutation seems has no effect on the antigenic properties of neuraminidase but this substitution by any means causes lethal mutagenesis in the individual gene expression by reducing level of protein transcript.

Mechanisms of umuC-dependent mutagenesis

International Nuclear Information System (INIS)

Kato, Takeji; Kitagawa, Yoshinori

1985-01-01

Present status of studies on umcDC genes-induced mutagenesis is introduced. Specificity of umuCD-dependent and -independent base substitution and frameshift mutagenesis is presented. Biochemical examinations of U.V.-induced umuCD gene function are described. Previous studies suggest that umuCD genes are induced by SOS inhibitory systems, that gene products are directly responsible for mutagenesis, that base substitution is largely involved in inducible mutagenesis, and that many of frameshifts are induced irrespective of gene function. (Namekawa, K.)

The synthesis of 1-11C-labelled ethyl, propyl, butyl and isobutyl iodides and examples of alkylation reactions

International Nuclear Information System (INIS)

Laangstroem, B.; Antoni, G.; Gullberg, P.; Halldin, C.; Naagren, K.; Rimland, A.; Svaerd, H.

1986-01-01

New 11 C-labelled precursors [1- 11 C]ethyl,[1- 11 C]propyl, [1- 11 C]butyl, and [1- 11 C]isobutyl iodides have been prepared by a 3-step reaction route using a one-pot system. The labelled iodides were obtained in 20-55#percent# radiochemical yields and 65-95#percent# radiochemical purities, with a total time for synthesis of the order of 10-14 min. The labelled iodides have been used in alkylation reactions with nitrogen, oxygen and carbon nucleophiles. The nitrogen alkylation reactions are exemplified by the synthesis of the analgetics N-[1- 11 C-ethyl]iodocaine and N-[1- 11 C-butyl] bupivacaine. The synthesis of 3-nitrophenyl[1- 11 C]propyl ether is also presented in this paper as an example of an oxygen alkylation. (author)

Gas chromatography-mass spectrometric studies of O-alkyl O-2-(N,N-dialkylamino) ethyl alkylphosphonites(phosphonates) for chemical weapons convention verification.

Science.gov (United States)

Saeidian, Hamid; Babri, Mehran; Ramezani, Atefeh; Ashrafi, Davood; Sarabadani, Mansour; Naseri, Mohammad Taghi

2013-01-01

The electron ionization (EI) mass spectra of a series of O-alkyl O-2-(N,N-dialkylaminolethyl alkylphosphonites(phosphonates), which are precursors of nerve agents, were studied for Chemical Weapons Convention (CWC) verification. General El fragmentation pathways were constructed and discussed. Proposed fragment structures were confirmed through analyzing fragment ions of deuterated analogs and density functional theory (DFT) calculations. The observed fragment ions are due to different fragmentation pathways such as hydrogen and McLafferty+1 rearrangements, alkene, amine and alkoxy elimination by alpha- or beta-cleavage process. Fragment ions distinctly allow unequivocal identification of the interested compounds including those of isomeric compounds. The presence and abundance of fragment ions were found to depend on the size and structure of the alkyl group attached to nitrogen, phosphorus and oxygen atoms.

Procedimiento para la obtención de cimetidina polimorfo "A" a partir de cimetidina polimorfo "B" impuro

Directory of Open Access Journals (Sweden)

Jesús García Valdés

1998-12-01

Full Text Available Se describen procedimientos que permiten mediante cristalización en mezclas alcohol etílico-agua (solventes de producción nacional, obtener cimetidina polimorfo A que cumple los requerimientos de la Farmacopea de los EE.UU. a partir de polimorfos A y B impuros. Se estableció que si el contenido de impureza era igual o menor al doble del permitido, podía utilizarse alcohol etílico absoluto con un rendimiento en peso superior al 70 %, pero si el contenido de impurezas estaba entre 2 y 3 veces, era necesario utilizar alcohol etílico con un contenido de agua del 6 % y un rendimiento en peso del 60 al 65 %. Se presentan además los resultados obtenidos durante su comprobación a escala industrial.The methods allowing the crystallizations of ethyl-alcohol-water mix and the obtention of an A polymorph cimetidine from impure A and B polymorphs in compliance with the requirements set by US Pharmacopeia are described. It was established that if the impurity content was equal to or lower than twice the allowable limit, then absolute ethyl alcohol with a weigth yield over 70 % could be used; however, if the impurity content doubled or tripled the said allowable level, then it would be necessary to use ethyl alcohol with a 6 % content and a weight yield from 60 to 65 %. Also, results obtained from testing at an industrial scale presented.

The pathologic effect of a novel neomorphic Fgf9(Y162C allele is restricted to decreased vision and retarded lens growth.

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Oliver Puk

Full Text Available Fibroblast growth factor (Fgf signalling plays a crucial role in many developmental processes. Among the Fgf pathway ligands, Fgf9 (UniProt: P54130 has been demonstrated to participate in maturation of various organs and tissues including skeleton, testes, lung, heart, and eye. Here we establish a novel Fgf9 allele, discovered in a dominant N-ethyl-N-nitrosourea (ENU screen for eye-size abnormalities using the optical low coherence interferometry technique. The underlying mouse mutant line Aca12 was originally identified because of its significantly reduced lens thickness. Linkage studies located Aca12 to chromosome 14 within a 3.6 Mb spanning interval containing the positional candidate genes Fgf9 (MGI: 104723, Gja3 (MGI: 95714, and Ift88 (MGI: 98715. While no sequence differences were found in Gja3 and Ift88, we identified an A→G missense mutation at cDNA position 770 of the Fgf9 gene leading to an Y162C amino acid exchange. In contrast to previously described Fgf9 mutants, Fgf9(Y162C carriers were fully viable and did not reveal reduced body-size, male-to-female sexual reversal or skeletal malformations. The histological analysis of the retina as well as its basic functional characterization by electroretinography (ERG did not show any abnormality. However, the analysis of head-tracking response of the Fgf9(Y162C mutants in a virtual drum indicated a gene-dosage dependent vision loss of almost 50%. The smaller lenses in Fgf9(Y162C suggested a role of Fgf9 during lens development. Histological investigations showed that lens growth retardation starts during embryogenesis and continues after birth. Young Fgf9(Y162C lenses remained transparent but developed age-related cataracts. Taken together, Fgf9(Y162C is a novel neomorphic allele that initiates microphakia and reduced vision without effects on organs and tissues outside the eye. Our data point to a role of Fgf9 signalling in primary and secondary lens fiber cell growth. The results

The novel mouse mutant, chuzhoi, has disruption of Ptk7 protein and exhibits defects in neural tube, heart and lung development and abnormal planar cell polarity in the ear

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Paudyal Anju

2010-08-01

Full Text Available Abstract Background The planar cell polarity (PCP signalling pathway is fundamental to a number of key developmental events, including initiation of neural tube closure. Disruption of the PCP pathway causes the severe neural tube defect of craniorachischisis, in which almost the entire brain and spinal cord fails to close. Identification of mouse mutants with craniorachischisis has proven a powerful way of identifying molecules that are components or regulators of the PCP pathway. In addition, identification of an allelic series of mutants, including hypomorphs and neomorphs in addition to complete nulls, can provide novel genetic tools to help elucidate the function of the PCP proteins. Results We report the identification of a new N-ethyl-N-nitrosourea (ENU-induced mutant with craniorachischisis, which we have named chuzhoi (chz. We demonstrate that chuzhoi mutant embryos fail to undergo initiation of neural tube closure, and have characteristics consistent with defective convergent extension. These characteristics include a broadened midline and reduced rate of increase of their length-to-width ratio. In addition, we demonstrate disruption in the orientation of outer hair cells in the inner ear, and defects in heart and lung development in chuzhoi mutants. We demonstrate a genetic interaction between chuzhoi mutants and both Vangl2Lp and Celsr1Crsh mutants, strengthening the hypothesis that chuzhoi is involved in regulating the PCP pathway. We demonstrate that chuzhoi maps to Chromosome 17 and carries a splice site mutation in Ptk7. This mutation results in the insertion of three amino acids into the Ptk7 protein and causes disruption of Ptk7 protein expression in chuzhoi mutants. Conclusions The chuzhoi mutant provides an additional genetic resource to help investigate the developmental basis of several congenital abnormalities including neural tube, heart and lung defects and their relationship to disruption of PCP. The chuzhoi mutation

Modification of the Neurospora crassa plasma membrane [H+]-ATPase with N,N'-dicyclohexycarbodiimide

International Nuclear Information System (INIS)

Sussman, M.R.; Slayman, C.W.

1983-01-01

The carboxyl-modifying reagent N,N'-dicyclohexylcarbodiimide (DCCD) inactivates the ATPase with pseudo-first order kinetics, suggesting that one site on the enzyme is involved. The rate constant for inactivation at pH 7.5 and 30 0 C is approximately 1000 M -1 min -1 , similar to values reported for the DCCD-binding proteolipid of F 0 -F 1 -type [H + ]-ATPases and for the sarcoplasmic reticulum [Ca +2 ]-ATPase. Although hydrophobic carbodiimides are inhibitory at micromolar concentrations, a hydrophilic analogue, 1-ethyl-3-(dimethylaminopropyl)-carbodiimide, is completely inactive even at millimolar concentrations. This result implies that the DCCD-reactive site is located in a lipophilic environment. [ 14 C]DCCD is incorporated into the M/sub r/ = 104,000 polypeptide at a rate similar to the rate of inactivation. There is no evidence for a separate low molecular weight DCCD-binding proteolipid. Using quantitative amino acid analysis, we established that complete inhibition occurs at a stoichiometry of 0.4 mol of DCCD/mol of polypeptide. Overall, the results are consistent with the idea the DCCD reacts with a single amino acid residue of the Neuspora [H + ]-ATPase, thereby blcoking ATP hydrolysis and proton translocation. 21 references, 5 figures, 2 tables

Comparison of the neurotoxicities between volatile organic compounds and fragrant organic compounds on human neuroblastoma SK-N-SH cells and primary cultured rat neurons

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Yasue Yamada

2015-01-01

Full Text Available These are many volatile organic compounds (VOCs that are synthesized, produced from petroleum or derived from natural compounds, mostly plants. Fragrant and volatile organic compounds from plants have been used as food additives, medicines and aromatherapy. Several clinical and pathological studies have shown that chronic abuse of VOCs, mainly toluene, causes several neuropsychiatric disorders. Little is known about the mechanisms of neurotoxicity of the solvents. n-Octanal, nonanal, and 2-ethyl-1-hexanol, which are used catalyzers or intermediates of chemical reactions, are released into the environment. Essential oils have the functions of self-defense, sterilization, and antibiosis in plants. When volatile organic compounds enter the body, there is the possibility that they will pass through the blood–brain barrier (BBB and affect the central nervous system (CNS. However, the direct effects of volatile organic compounds on neural function and their toxicities are still unclear. We compared the toxicities of n-octanal, nonanal and 2-ethyl-1-hexanol with those of five naturally derived fragrant organic compounds (FOCs, linalool, cis-3-hexen-1-ol, isoamyl alcohol, n-propyl alcohol and n-phenethyl alcohol. MTT assay of human neuroblastoma SK-N-SH cells showed that the IC50 values of linalool, cis-3-hexen-1-ol, isoamyl alcohol, n-propyl alcohol and phenethyl alcohol were 1.33, 2.3, >5, >5, and 2.39 mM, respectively, and the IC50 values of toluene, n-octanal, nonanal and 2-ethyl-1-hexanol were 850, 37.2, 8.31 and 15.1 μM, respectively. FOCs showed lower toxicities than those of VOCs. These results indicate that FOCs are safer than other compounds.

Identification of Mouse Cytomegalovirus Resistance Loci by ENU Mutagenesis

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Philippe Georgel

2009-10-01

Full Text Available Host resistance to infection depends on the efficiency with which innate immune responses keep the infectious agent in check. Innate immunity encompasses components with sensing, signaling and effector properties. These elements with nonredundant functions are encoded by a set of host genes, the resistome. Here, we review our findings concerning the resistome. We have screened randomly mutagenized mice for susceptibility to a natural opportunistic pathogen, the mouse cytomegalovirus. We found that some genes with initially no obvious functions in innate immunity may be critical for host survival to infections, falling into a newly defined category of genes of the resistome.

Density, refraction index and vapor–liquid equilibria of N-methyl-2-hydroxyethylammonium butyrate plus (methyl acetate or ethyl acetate or propyl acetate) at several temperatures

International Nuclear Information System (INIS)

Alvarez, V.H.; Mattedi, S.; Aznar, M.

2013-01-01

Highlights: ► Densities, refraction indices and VLE were measured for ester + m-2-HEAB mixtures. ► V E , apparent molar volumes and thermal expansion coefficients were calculated. ► Peng–Robinson EoS + Wong–Sandler mixing rule + COSMO-SAC predicted the data. -- Abstract: This paper reports the densities, refraction indices, and vapor liquid equilibria for binary systems ester + N-methyl-2-hydroxyethylammonium butyrate (m-2-HEAB): methyl acetate (1) + m-2-HEAB (2), ethyl acetate (1) + m-2-HEAB and propyl acetate (1) + m-2-HEAB (2). The excess molar volumes, deviations in the refraction index, apparent molar volumes, and thermal expansion coefficients for the binary systems were fitted to polynomial equations. The Peng–Robinson equation of state, coupled with the Wong–Sandler mixing rule, is used to describe the experimental data. Since the predictive activity coefficient model COSMO-SAC is used in the Wong–Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the vapor–liquid equilibria have a deviation lower than 1.0% and 1.1%, respectively

Ab initio Study of Alkyl-oxonium Cations CnH2n+1OH2+, n=1,2,3,4

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Francis F. Muguet

2004-08-01

Full Text Available ABSTRACT: Within the framework of the itinerant radical model, the solvated electron in liquid alcohols is understood as an itinerant alkyl-oxonium ROH2. radical. As a first step in the investigation of those radicals, this study deals with the optimization of related ROH2+ alky-oxonium cations: CnH2n+1OH2+,n=1,2,3,4. The structures were optimized at the MP2/6-31G**++ level with the help of the GAMESS ab initio package. Optimized structures are reported for the following cations: MethylOxonium; EthylOxonium; 1-PropylOxonium, 2-PropylOxonium and 1-ButylOxonium, 2-ButylOxonium, IsoButylOxonium, TertButylOxonium. Optimized geometries are displayed with the help of the ChemApp Java applet. Vibrational frequencies and ZPEs have been computed, and visual depictions of expected experimental IR spectra have been simulated with the help of Lorentzian functions.

Crystal structure of diaquabis(N,N-diethylnicotinamide-κN1bis(2,4,6-trimethylbenzoato-κO1cobalt(II

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Gülçin Şefiye Aşkın

2016-04-01

Full Text Available The centrosymmetric molecule in the monomeric title cobalt complex, [Co(C10H11O22(C10H14N2O2(H2O2], contains two water molecules, two 2,4,6-trimethylbenzoate (TMB ligands and two diethylnicotinamide (DENA ligands. All ligands coordinate to the CoII atom in a monodentate fashion. The four O atoms around the CoII atom form a slightly distorted square-planar arrangement, with the distorted octahedral coordination sphere completed by two pyridine N atoms of the DENA ligands. The dihedral angle between the planar carboxylate group and the adjacent benzene ring is 84.2 (4°, while the benzene and pyridine rings are oriented at a dihedral angle of 38.87 (10°. The water molecules exhibit both intramolecular (to the non-coordinating carboxylate O atom and intermolecular (to the amide carbonyl O atom O—H...O hydrogen bonds. The latter lead to the formation of layers parallel to (100, enclosing R44(32 ring motifs. These layers are further linked via weak C—H...O hydrogen bonds, resulting in a three-dimensional network. One of the two ethyl groups of the DENA ligand is disordered over two sets of sites with an occupancy ratio of 0.490 (13:0.510 (13.

Erbb2 Is Required for Cardiac Atrial Electrical Activity during Development

Czech Academy of Sciences Publication Activity Database

Tenin, G.; Clowes, Ch.; Wolton, K.; Krejčí, Eliška; Wright, J. A.; Lovell, S. C.; Sedmera, David; Hentges, K. E.

2014-01-01

Roč. 9, č. 9 (2014), e107041 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA13-12412S; GA ČR(CZ) GAP302/11/1308 Institutional support: RVO:67985823 Keywords : mouse * embryo * atrium * conduction * optical mapping * ENU mutagenesis Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 3.234, year: 2014

9-Ethyl-2,3-dihydro-9H-carbazol-4(1H-one

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S. Sriman Narayanan

2008-09-01

Full Text Available In the title compound, C28H30N2O2, the cyclohexene ring system adopts a sofa conformation. The crystal structure is stabilized by C—H...O interactions between methyl H atoms of the ethyl substituents and the O atoms of carbonyl groups of adjacent molecules, and by an intermolecular carbonyl–carbonyl interactions [3.207 (2 Å

Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana

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Kazama Yusuke

2011-11-01

Full Text Available Abstract Background Heavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. Heavy-ion beams show high linear energy transfer (LET and thus more effectively induce DNA double-strand breaks than other mutagenic techniques. Previously, we determined the most effective heavy-ion LET (LETmax: 30.0 keV μm-1 for Arabidopsis mutagenesis by analysing the effect of LET on mutation induction. However, the molecular structure of mutated DNA induced by heavy ions with LETmax remains unclear. Knowledge of the structure of mutated DNA will contribute to the effective exploitation of heavy-ion beam mutagenesis. Results Dry Arabidopsis thaliana seeds were irradiated with carbon (C ions with LETmax at a dose of 400 Gy and with LET of 22.5 keV μm-1 at doses of 250 Gy or 450 Gy. The effects on mutation frequency and alteration of DNA structure were compared. To characterise the structure of mutated DNA, we screened the well-characterised mutants elongated hypocotyls (hy and glabrous (gl and identified mutated DNA among the resulting mutants by high-resolution melting curve, PCR and sequencing analyses. The mutation frequency induced by C ions with LETmax was two-fold higher than that with 22.5 keV μm-1 and similar to the mutation frequency previously induced by ethyl methane sulfonate. We identified the structure of 22 mutated DNAs. Over 80% of the mutations caused by C ions with both LETs were base substitutions or deletions/insertions of less than 100 bp. The other mutations involved large rearrangements. Conclusions The C ions with LETmax showed high mutation efficiency and predominantly induced base substitutions or small deletions/insertions, most of which were null mutations. These small alterations can be determined by single-nucleotide polymorphism (SNP detection systems. Therefore, C ions with LETmax might be useful as a highly efficient reverse genetic system in conjunction with SNP detection

Detection of new MHC mutations in mice by skin grafting, tumor transplantation and monoclonal antibodies: a comparison

International Nuclear Information System (INIS)

Egorov, I.K.; Egorov, O.S.

1988-01-01

Two mechanisms of major histocompatibility complex (MHC) mutations have been described in mice: gene conversion and homologous but unequal recombination. However, the knowledge of mutations in MHC is incomplete because studies have been limited almost exclusively to two haplotypes, H-2/sup b/ and H-2/sup d/, while hundreds of haplotypes exist in nature; it has been biased by the use of only one procedure of screening for mutation, skin grafting. The authors used three procedures to screen for MHC mutations: (1) conventional techniques of skin grafting, (2) syngeneic tumor transplantation and (3) typing with monoclonal anti-MHC antibodies (mAbs) and complement. The faster technique of tumor transplantation detected mutants similar to those discovered by skin grafting technique. Screening with mAbs allowed us to detect both mutants that are capable of rejecting standard skin grafts and those that are silent in skin grafting tests, and which therefore resulted in a higher apparent mutation frequency. Two mutants of the H-2/sup a/ haplotype were found that carry concomitant class I and class II antigenic alterations. Both MHC mutants silent in skin grafting tests and mutants carrying concomitant class I and class II alterations have never been studied before and are expected to reveal new mechanisms of generating MHC mutations. 1-Ethyl-1-nitrosourea (ENU) failed to induce de novo MHC mutations in our skin grafting series

Screening of high-yield GTF yeast by N+-implantation

International Nuclear Information System (INIS)

Gao Yanhong; Lv Jiaping; Liu Lu; Li Shurong

2009-01-01

In this study, one of the highest chromium-resistant strain was screened from 12 tested brewer's yeast. N + ion implantation was used to mutate this yeast and screened high-yield GTF yeast strains with Chromium tolerance method. The mutagenesis was conducted by 50 KeV N + ion implantation with the doses of 1 x 2.6 x 10 13 , 2 x 2.6 x 10 13 , 3 x 2.6 x 10 13 , 4 x 2.6 x 10 13 , 5 x 2.6 x 10 13 and 6 x 2.6 x 10 13 ion/cm 2 . Results showed that the optimum dose was 4 x 2.6 x 10 13 ion/cm 2 , and a strain M11-1A11 of high-producing GTF was obtained. Its organic Cr content was increased by 22.4% than the original strain. Its fermentation property was stable after 5 generation transfer inoculation. (authors)

Liver damage caused by hepatitis C viral infection and ethyl alcohol consumption

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Kostić Velimir

2006-01-01

Full Text Available Background/Aim. Hepatitis C virus infection (HCV is a complex disease, most commonly chronicle (80-85%. The aim of this research was to determinate the level of the liver damage in the patients cansed by HCV in conjunction with consuming ethyl alcohol. Methods. The research included 15 patients with chronic HCV infection supported by the misuse of ethyl alcohol, as well. The diagnosis of C infection hepatitis was proved using the ELISA test and PCR method. Results. The results of the study showed the liver damage by both HCV infection and ethyl alcohol, which was verified by the presence of biochemical changes and patohystological processing of the patients (liver biopsy and prosection. Patohystological changes were at the level of liver cirrhosis and carcinoma (2 patients. There was a signficant difference between the two subgroups (p < 0.001 regarding the examined values γ-GT, PLT and PTV. The basic therapeutic procedure was to introduce this category of patients into alcohol abstinence, and, in a few patients, to apply the antivirus therapy, as well. Conclusion. Based on the number of the examined patients (n = 15, we could conclude that a prolonged ethyl alcohol misuse with the presence of HCV infection was in a correlation with the liver disease progression.

Synthesis of 1-/sup 11/C-labelled ethyl, propyl, butyl and isobutyl iodides and examples of alkylation reactions

Energy Technology Data Exchange (ETDEWEB)

Laangstroem, B.; Antoni, G.; Gullberg, P.; Halldin, C.; Naagren, K.; Rimland, A.; Svaerd, H.

1986-01-01

New /sup 11/C-labelled precursors (1-/sup 11/C)ethyl,(1-/sup 11/C)propyl, (1-/sup 11/C)butyl, and (1-/sup 11/C)isobutyl iodides have been prepared by a 3-step reaction route using a one-pot system. The labelled iodides were obtained in 20-55% radiochemical yields and 65-95% radiochemical purities, with a total time for synthesis of the order of 10-14 min. The labelled iodides have been used in alkylation reactions with nitrogen, oxygen and carbon nucleophiles. The nitrogen alkylation reactions are exemplified by the synthesis of the analgetics N-(1-/sup 11/C-ethyl)iodocaine and N-(1-/sup 11/C-butyl) bupivacaine. The synthesis of 3-nitrophenyl(1-/sup 11/C)propyl ether is also presented in this paper as an example of an oxygen alkylation.

Nuclear translocation of mismatch repair proteins MSH2 and MSH6 as a response of cells to alkylating agents.

Science.gov (United States)

Christmann, M; Kaina, B

2000-11-17

Mammalian mismatch repair has been implicated in mismatch correction, the prevention of mutagenesis and cancer, and the induction of genotoxicity and apoptosis. Here, we show that treatment of cells specifically with agents inducing O(6)-methylguanine in DNA, such as N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea, elevates the level of MSH2 and MSH6 and increases GT mismatch binding activity in the nucleus. This inducible response occurs immediately after alkylation, is long-lasting and dose-dependent, and results from translocation of the preformed MutSalpha complex (composed of MSH2 and MSH6) from the cytoplasm into the nucleus. It is not caused by an increase in MSH2 gene activity. Cells expressing the DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT), thus having the ability to repair O(6)-methylguanine, showed no translocation of MutSalpha, whereas inhibition of MGMT by O(6)-benzylguanine provoked the translocation. The results demonstrate that O(6)-methylguanine lesions are involved in triggering nuclear accumulation of MSH2 and MSH6. The finding that treatment of cells with O(6)-methylguanine-generating mutagens results in an increase of MutSalpha and GT binding activity in the nucleus indicates a novel type of genotoxic stress response.

Impact of gate engineering in enhancement mode n++GaN/InAlN/AlN/GaN HEMTs

Science.gov (United States)

Adak, Sarosij; Swain, Sanjit Kumar; Rahaman, Hafizur; Sarkar, Chandan Kumar

2016-12-01

This paper illustrate the effect of gate material engineering on the performance of enhancement mode n++GaN/InAlN/AlN/GaN high electron mobility transistors (HEMTs). A comparative analysis of key device parameters is discussed for the Triple Material Gate (TMG), Dual Material Gate (DMG) and the Single Material Gate (SMG) structure HEMTs by considering the same device dimensions. The simulation results shows that an significant improvement is noticed in the key analysis parameters such as drain current (Id), transconductance (gm), cut off frequency (fT), RF current gain, maximum cut off frequency (fmax) and RF power gain of the gate material engineered devices with respect to SMG normally off n++GaN/InAlN/AlN/GaN HEMTs. This improvement is due to the existence of the perceivable step in the surface potential along the channel which successfully screens the drain potential variation in the source side of the channel for the gate engineering devices. The analysis suggested that the proposed TMG and DMG engineered structure enhancement mode n++GaN/InAlN/AlN/GaN HEMTs can be considered as a potential device for future high speed, microwave and digital application.

N,N,N-Tris(diphenylphosphorylmethylamine

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Olaf Walter

2017-10-01

Full Text Available The structure of N,N,N-tris(diphenylphosphorylmethylamine, C39H36NO3P3, at 103 K has monoclinic (P21/c symmetry. Two molecules, each with pseudo-threefold rotation symmetry, crystallize in the asymmetric unit of the monoclinic unit cell. The compound acts as ligand for the stabilization of metal ions with flexible coordination enabling three- or fourfold coordination.