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Abstract  

In this paper, a promoter-probe plasmid pKK232-8 was used as a vector, which functioned in Escherichia coli TG1 host. The plasmid DNA fragments from Pseudomonas maltophilia AT18 chromosome DNA active as promoter inEscherichia coli TG1, the promoter function was studied by means of microcalorimetry, the promoter is about 800 bp DNA, it can promote the chloramphenicol (Cm) gene in plasmid pKK232-8, the Cm resistance level is about 80 μg mL–1, the promoter activity is high. It implicates that there are probably many promoters in Pseudomonas maltophilia AT18 chromosome. All these information is readily obtained by an LKB 2277-204 heat conduction microcalorimeter. Microcalorimetry is a quantitative, inexpensive, and versatile method for microbiological genetic research.

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Abstract  

The paper aims to investigate cytogenetic and apoptotic responses of γ-irradiation in a radio-resistant cell strain designated as M5. Induced micronuclei, chromosomal aberrations, nuclear fragmentation and nucleosomal ladders by γ-irradiation were less at equal doses in M5 cells in comparison with that obtained in the parental Chinese hamster V79 cells. However, at equal survival, there were no differences in the end points studied. Results indicate that the residual damages that lead to reproductive cell death also resulted in the cytogenetic and apoptotic responses. We speculate that the repair efficiency in M5 cells was more efficient and increased DNA repair could be the cause of radiation resistance observed in M5 cells.

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Summary

Genetic mutations, chromosomal breaks, and chromosomal rearrangements, which are induced due to organic impurities, are considered as potential genotoxic impurities. The European Medicines Agency (EMA) and the United States Food and Drug Administration (US FDA) have set a threshold of toxicological concern (TTC) of 1.5 µg per person per day for each impurity. A sensitive and simple high-performance thin-layer chromatography (HPTLC) method has been developed and validated for determination of the potential genotoxic impurity, namely, 2-chloroaniline, at trace levels in quetiapine fumarate. The method was found to be specific and selective for the application. The limit of detection (LOD) and limit of quantification (LOQ) for quetiapine fumarate were found to be 1.27 and 3.87 ng per band. The LOD and LOQ values for 2-chloroaniline were found 0.018 and 0.054 ng per band, respectively. The calibration curve for 2-chloroaniline was linear over a concentration range from 2.5 to 12.5 ng. The method was found to be specific, precise, linear, and accurate and can be employed for monitoring and estimation of levels of 2-chloroaniline in quetiapine fumarate.

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Summary

Genotoxic impurities can be described as impurities that can induce genetic mutations and chromosomal breaks, or that damage the genetic information within a cell, which may lead to cancer. The European Medical Agency (EMA) and the United States Food and Drug Administration (US FDA) have set a threshold of toxicological concern (TTC) of genotoxic impurities 1.5 µg per day. In a continuous effort to develop an analytical method for the estimation of genotoxic impurities in quetiapine fumarate, a sensitive, simple, and precise high-performance thin-layer chromatography method has been developed and validated for the determination of 2-nitrophenyl (phenyl)sulfane as a genotoxic impurity at trace levels. The limits of detection (LOD) for quetiapine fumarate and 2-nitrophenyl (phenyl)sulfane were found to be 5.11 and 15.5 ng per band, whereas the limits of quantification (LOQ) were observed 0.09 and 0.3 ng per band, respectively. The calibration curve for 2-nitrophenyl (phenyl)sulfane was linear over the concentration range of 10 to 50 ng per band. The method was found to be specific, precise, linear, and accurate for the estimation of 2-nitrophenyl (phenyl)sulfane at trace levels in quetiapine fumarate.

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Abstract  

(6-3H)-Thymidine, (5-3H)-methyl-thymidine, and (5-3H)-thymidine were synthesized by the use of tritiated water. The specific activities of the products were 3.3, 3.4 and 3.0 mCi/mM, respectively. These tritiated thymidines are important tracers to study human lymphocytes and human chromosomes.

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.A. Levin , The Role of Chromosomal Change in Plant Evolution , Oxford University Press , New York, NY , 2002 . [5] J. Patočka

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Zhang Shuyan, Wang Xizhong, Wang Zishu, Cheng Wenyuan, Jin Jianan, Zhang Jiazao, Xu Daoquan, Shao Yuesheng, Luo Changrong, Wang Juan, Wu Kejia and Zhou Maolun

Abstract  

Na2 1 1At and2 1 1At–Te colloid injections were prepared. By comparison with tissue distribution of Na2 1 1At and2 1 1At–Te colloid injections it has been demonstrated that the2 1 1At–Te colloid is stable in vivo. It has been shown that the radiohalogen,2 1 1At, has huge and extensive radiobiological effects in studying on the changes in histopathology, enzyme histochemistry, chromosome aberration, micronucleus frequency of bone-marrow polychromatic erythrocytes and the injury effect of2 1 1At on experimental Ehrlich ascites cells.

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Abstract  

The number of chromosomal and chromatid breaks, deletions, as well as fragments, have been followed in correlation to the physical dose as assessed by the specific radioactivity of DNA. Human lymphocytes from adult donors were incubated for 44 hours in media supplemented with tritiated thymidine. An uneven distribution of labelling in the cell population has been found and about 50% of the population of cells remained unlabelled. The dose-response curve was flat reflecting loss of damaged cells and/or repair of damage. The dose-response curve showed that at the experimental conditions used the dose of 100 mGy absorbed from incorporated tritium caused about 0.1 deletions per. cell. Doubling the number of deletions to about 0.2 per cell required approximately a five times higher absorbed dose.

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Résumé  

La rétraction et l'extension liées à l'âge, des boucles des chromosomes en écouvillon des amphibiens peuvent être en relation avec la quantité de métal alcalin dans les oeufs qui les contiennent. Pour les analyses par absorption atomique faites précédemment on devait extraire le nucléoplasme de 50 oeufs afin d'obtenir une quantité de matière suffisante pour effectuer des dosages précis. La haute sensibilité de l'analyse par activation neutronique et le fait de pouvoir éviter les blancs dues aux réactifs, permettant d'analyser un seul noyau à la fois. On obtient ainsi une information qu'il était impossible d'avoir masquée quand un plus grand nombre d'échantillons étaient traités ensembles.

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for induced duplication of the chromosomes in plants [ 21 ]. The substance Kepone (1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[c,d]pentalen-2-one) is an organochlorine found in pesticide, insecticide, and fungicide [ 22

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