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Host cell reactivation capacity for ozonated or irradiated phage was determined for different strains of E. coli either more sensitive or resistant to ozone than the wild type strain. The results suggest that the ozr gene product could be involved in the same repair pathway for ozone-induced lesions on DNA as the polA gene. The possible involvement of a specific endonuclease for these lesions is also considered. 相似文献
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Summary Host cell reactivation capacity for ozone T3 phage was determined for differentE. coli strains deficient in one or more of the DNA repair mechanisms. The results indicate that DNA polymerase I appears to play a key role in the repair of damage produced on the DNA by ozone while thelexA gene product seems to play a minor one.This research was sponsored by the National Sciences and Engineering Council of Canada. One of us (PLH) acknowledges a scholarship from the NSERCof Canada. 相似文献
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Cell survival and deoxyribonucleic acid (DNA) degradation wave measured for wild-type Escherichia coli B251 cells after exposure to different concentrations of ozone. The results show that extensive breakdown of DNA occurs after ozonation and that the extent of ozone-induced DNA degradation generally correlates with the colony-forming ability of the cells. 相似文献
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K. C. Saxena S. Ghatak S. C. Agarwala 《Cellular and molecular life sciences : CMLS》1954,10(12):488-489
Zusammenfassung Zusatz von Vitamin B12 in Kulturnährböden hemmt die Thiamin-Biosynthese von frisch isoliertenE.-coli-Stämmen. Diese Hemmung steht im Verhältnis zur zugesetzten Menge von Vitamin B12. 相似文献
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J. Jännes 《Cellular and molecular life sciences : CMLS》1955,11(9):344-345
Zusammenfassung Auf vitaminfreien Nährböden wurdenEscherichia-Coli-Stämme kultiviert, die bei Zusatz von Vitamin B12 einen deutlichen Rückgang der Abgabe von Pantothensäure in das Nährmedium zeigten.Die Bestimmung des Coenzym-A-Gehaltes der Bakterien ist mittels der Methode vonKaplan undLipmann durchgeführt worden. Es ergab sich, dass keine grösseren Schwankungen des Coenzym-A-Gehaltes der Bakterien vorkamen, obgleich der Gehalt an freier Pantothensäure in der Nährflüssigkeit deutlich abnahm.
This work has been aided by grants from Emil Aaltonen Foundation and Sigrid Juselius Stiftelse. 相似文献
This work has been aided by grants from Emil Aaltonen Foundation and Sigrid Juselius Stiftelse. 相似文献
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Self-stimulatory growth factors, produced by a human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, have been tested for the capacity to induce DNA synthesis in various human and animal cell lines, including lymphoid, either EBV-positive or EBV-negative, and non-lymphoid cell lines. It has been found that BA-D10-4 cells produce growth factors which seem to be essential for their sustained proliferation in vitro, and which increase DNA synthesis in different primate lymphoid cells, independently of the presence of the EBV genome and of the lymphocyte lineage. 相似文献
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Zusammenfassung Die Wirkung des Farbstoffes Trypanblau auf die embryonale Entwicklung von 2 Mäusestämmen, des C57B1/6 Stammes und des Swiss-Albino-Stammes, wurde untersucht und die Ergebnisse wurden miteinander verglichen. Embryonen der beiden Stämme reagierten in verschiedener Weise auf Trypanblau. Die Injektion des Farbstoffes führte zum vollständigen Entwicklungsstillstand aller C57B1/6-Embryonen, während bei Swiss-Albino-Embryonen hauptsächlich Kopf-, Gehirn-und Schwanzabnormitäten auftraten. Bei Swiss-Embryonen nahm die Schwere der Abnormität mit fortschreitendem Alter der Embryos beträchtlich ab, obwohl die Anzahl pro Wurf unverändert blieb. Keine Veränderung in der Zahl der Abnormitäten wurde in älteren C57B1/6-Embryonen beobachtet. Die verschiedenartige Reaktion der beiden Stämme auf Trypanblau ist vielleicht darauf zurückzuführen, dass genetisch bedingte Unterschiede in der Fähigkeit, zerstörtes Gewebe während der embryonalen Entwicklung zu reparieren, vorhanden sind.
Submitted in partial fulfillment of the requirements for the degree of Master of Arts in the Graduate Division of the College of Liberal Arts and Science of the City College of the City University of New York. 相似文献
Submitted in partial fulfillment of the requirements for the degree of Master of Arts in the Graduate Division of the College of Liberal Arts and Science of the City College of the City University of New York. 相似文献
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Summary Self-stimulatory growth factors, produced by a human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, have been tested for the capacity to induce DNA synthesis in various human and animal cell lines, including lymphoid, either EBV-positive or EBV-negative, and non-lymphoid cell lines. It has been found that BA-D10-4 cells produce growth factors which seem to be essential for their sustained proliferation in vitro, and which increase DNA synthesis in different primate lymphoid cells, independently of the presence of the EBV genome and of the lymphocyte lineage. 相似文献
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The duration of the various development stages of the seminiferous epithelium in different strains of male mice was determined by scoring the frequency distribution in randomly selected tubule cross-sections. The results obtained show a difference in the duration of the various stages between the different strains. 相似文献
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A Paraf E Faivre V Zilberfarb L Lelièvre A Zachowski 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,281(10):683-685
Using cAMP or theophyllin as selective agents, we obtained from contact inhibited and non contact inhibited cell lines, derived from the same plasmocytoma, different resistant cell lines. All of them were cAMP and theophyllin resistant and also ouabain and con A resistant as judged by the growth curves in presence of the different drugs. 相似文献