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1.
Om Parkash 《Cellular and molecular life sciences : CMLS》1967,23(10):859-861
Zusammenfassung Wird Thymidin dem Standardnährboden vonDrosophila zugefügt (1–2%), erweist es sich als teratogen. Bei Versuchen mit verschiedenen Stämmen vonD. melanogaster traten in allen Fällen nach Behandlung wiederholt morphologische Missbildungen einer ganz bestimmten Kategorie auf. Ausserdem erwies sich Thymidin bei diesen Konzentrationen auch als mutagen zumindest in bezug auf die Auslösung geschlechtsgebundener rezessiver Letalfaktoren. Der mutagene Effekt kann durch Röntgenbestrahlung des Thymidins vor der Anwendung herabgesetzt werden. Auf die möglichen Ursachen der teratogenen und mutagenen Wirkung des Thymidins beiD. melanogaster wird hingewiesen. 相似文献
2.
O. Parkash 《Cellular and molecular life sciences : CMLS》1968,24(7):726-727
Zusammenfassung Der Autor hat bereits früher über den teratogenen Effekt von Thymidin beiD. melanogaster berichtet. Die vorliegende Arbeit befasst sich mit demselben Phänomen bei anderenDrosophila-Arten undMegaselia scalaris (Phoridae). Während der teratogene Effekt beiD. simulans, D. mercatorum undD. funebris der gleiche wie beiD. melanogaster ist, tritt beiD. subobscura andMegaselia scalaris keine teratogene Wirkung auf. Die für die genannten Arten verwendete Thymidinkonzentration erweist sich fürD. hydei als stark toxisch und verhindert die Verpuppung vollkommen. Das Ergebnis zeigt, dass verschiedene genetische Systeme sehr unterschiedlich auf ein und dieselbe chemische Substanz reagieren können.
This work was done in the Institute of Biology of the University of Vienna (Head: Prof. Dr. F.Mainx) and the author is thankful for guidance and laboratory facilities. 相似文献
This work was done in the Institute of Biology of the University of Vienna (Head: Prof. Dr. F.Mainx) and the author is thankful for guidance and laboratory facilities. 相似文献
3.
Esterase polymorphism in a population ofZaprionus paravittiger 总被引:1,自引:0,他引:1
R. Parkash 《Cellular and molecular life sciences : CMLS》1980,36(10):1164-1165
Summary Esterase isozyme variation inZaprionus paravittiger is controlled by multiple alleles at 2 autosomal loci (Est-1 and Est-3). Est-1 codes for dimeric esterases while Est-3 codes for monomeric esterases. The degree and pattern of esterase polymorphism have been described. 相似文献
4.
O. Parkash 《Cellular and molecular life sciences : CMLS》1969,25(9):998-998
Zusammenfassung BeiDrosophila melanogaster wurde ein temperaturabhängiger Letalfaktor gefunden. Die Temperaturabhängigkeit der Manifestation wird mit dem Vorhandensein von Modifikationsgenen erklärt. 相似文献
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6.
Synthesis of Schiff bases of naphtha[1,2-d]thiazol-2-amine and metal complexes of 2-(2′-hydroxy)benzylideneaminonaphthothiazole as potential antimicrobial agents 下载免费PDF全文
Objective: A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Methods: Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2′-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results: All the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2′-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent. Conclusion: The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases. 相似文献
7.
Mutagenic effect of irradiated DNA in Drosophila melanogaster 总被引:1,自引:0,他引:1
8.
Guernsey DL Matsuoka M Jiang H Evans S Macgillivray C Nightingale M Perry S Ferguson M LeBlanc M Paquette J Patry L Rideout AL Thomas A Orr A McMaster CR Michaud JL Deal C Langlois S Superneau DW Parkash S Ludman M Skidmore DL Samuels ME 《Nature genetics》2011,43(4):360-364
Meier-Gorlin syndrome is a rare autosomal recessive genetic condition whose primary clinical hallmarks include small stature, small external ears and small or absent patellae. Using marker-assisted mapping in multiple families from a founder population and traditional coding exon sequencing of positional candidate genes, we identified three different mutations in the gene encoding ORC4, a component of the eukaryotic origin recognition complex, in five individuals with Meier-Gorlin syndrome. In two such individuals that were negative for mutations in ORC4, we found potential mutations in ORC1 and CDT1, two other genes involved in origin recognition. ORC4 is well conserved in eukaryotes, and the yeast equivalent of the human ORC4 missense mutation was shown to be pathogenic in functional assays of cell growth. This is the first report, to our knowledge, of a germline mutation in any gene of the origin recognition complex in a vertebrate organism. 相似文献
9.
Sat Parkash Sharma 《Cellular and molecular life sciences : CMLS》1961,17(3):125-126
Résumé Des lipofuscines, corps pigments jaune-sale à brun-sombre, ont été observées dans les neurones vivants et fixés de quelques reptiles. L'auteur y a aussi constaté la présence de corps pigmentés extracellulaires, noir-brunâtre, de nature histochimique inconnue. 相似文献
10.
Chen Y Yee D Dains K Chatterjee A Cavalcoli J Schneider E Om J Woychik RP Magnuson T 《Nature genetics》2000,24(3):314-317
The ability to generate mutations is a prerequisite to functional genetic analysis. Despite a long history of using mice as a model system for genetic analysis, the scientific community has not generated a comprehensive collection of multiple alleles for most mouse genes. The chemical mutagen of choice for mouse has been N-ethyl-N-nitrosourea (ENU), an alkylating agent that mainly causes base substitutions in DNA, and therefore allows for recovery of complete and partial loss-, as well as gain-, of-function alleles . Specific locus tests designed to detect recessive mutations showed that ENU is the most efficient mutagen in mouse with an approximate mutation rate of 1 in 1,000 gametes. In fact, several genome-wide and region-specific screens based on phenotypes have been carried out. The anticipation of the completion of the human and mouse genome projects, however, now emphasizes genotype-driven genetics--from sequence to mutants. To take advantage of the mutagenicity of ENU and its ability to create allelic series of mutations, we have developed a complementary approach to generating mutations using mouse embryonic stem (ES) cells. We show that a high mutation frequency can be achieved and that modulating DNA-repair activities can enhance this frequency. The treated cells retain germline competency, thereby rendering this approach applicable for efficient generation of an allelic series of mutations pivotal to a fine-tuned dissection of biological pathways. 相似文献