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91.
Notch signaling is a direct determinant of keratinocyte growth arrest and entry into differentiation 总被引:37,自引:0,他引:37
92.
Frequency of Missense Mutations in the Coding Region of a Eukaryotic Gene Transferred by Retroviral Vectors 总被引:3,自引:0,他引:3
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Maria De Angioletti Ana Rovira Michel Sadelain Lucio Luzzatto Rosario Notaro 《Journal of virology》2002,76(4):1991-1994
A relatively high mutation rate is probably a major factor in the evolutionary success of retroviruses, because it generates the genetic diversity that helps them to cope with changes in the environment. When using recombinant retroviruses as vectors for gene transfer and gene therapy, it is important to consider the implications of this biological characteristic. Until now, the mutation rate has been studied by using noneukaryotic genes as reporters. Here we report point mutations in the human glucose-6-phosphate dehydrogenase (hG6PD) gene transferred by Moloney murine leukemia virus-based vectors into murine bone marrow cells and NIH 3T3 murine fibroblasts. After bone marrow transplantation, we observed an hG6PD with abnormal electrophoretic mobility for 2 out of 34 mice. Next, we studied this phenomenon quantitatively and found 1 electrophoretically abnormal hG6PD variant among 93 independently isolated NIH 3T3 clones, from which we estimate a mutation rate of 1.4 x 10(-5) per base pair per replication cycle. Mutations in the transferred gene can thus contribute to the impairment of the effectiveness of retrovirus-mediated gene transfer. 相似文献
93.
Biodegradation of phenols by microalgae 总被引:7,自引:0,他引:7
Gabriele Pinto Antonino Pollio Lucio Previtera Fabio Temussi 《Biotechnology letters》2002,24(24):2047-2051
Two green microalgae, Ankistrodesmus braunii and Scenedesmus quadricauda, degraded phenols (each tested at 400 mg ml–1) selected from olive-oil mill wastewaters, within 5 days, with a removal greater than 70%. Green algae may, therefore, represent an alternative to other biological treatment used for the biodegradation of phenol-containing wastewaters. 相似文献
94.
Information on the ultrastructure of parrot spermatids and spermatozoa is limited to only four species with no comprehensive study of spermiogenesis conducted within the order Psittaciformes. The present study was undertaken to describe the development of the cockatiel spermatid using electron microscopy. Four phases of spermatid maturation were documented on the basis of nuclear morphology, development of the acrosome, perforatorium, and axial filament. These phases included 1) round nuclei, 2) irregular nuclei, 3) elongated nuclei with granular chromatin, and 4) elongated nuclei with homogenous chromatin. While development of the cockatiel spermatid was comparable to that of other domestic avian species, we have noted the hollow nature of some chromatin granules, an abnormal formation of the axoneme, the absence of the fibrous sheath around the axoneme of the principal piece, and the absence of an annulus. J. Morphol. , 2012. © 2012 Wiley Periodicals, Inc. 相似文献
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98.
Maria de Lourdes Lucio Ferrarese Osvaldo Ferrarese-Filho JoĂo Domingos Rodrigues 《Acta Physiologiae Plantarum》2000,22(2):121-124
Ferulic acid uptake by soybean root in nutrient culture was investigated by the depletion method at different concentrations,
temperatures and pH. Results showed that soybean roots absorbed this compound at greater rates in the concentrations between
0.05-mM and 1.0-mM and it was concentration dependent. Ferulic acid uptake was unaffected at pH 4.5 or 6.0 but reduced at
pH 7.0. At pH 6.0, uptake rates decreased significantly with increasing temperature of nutrient solution. 相似文献
99.
The occurrence and isolation of two new yellow pigments, leptopsammin A and B, from methanolic extract of Leptopsammia pruvoti are described. The spectral properties (UV and MS) and colorimetric reactions of the leptopsammins suggest they are bromophenol compounds, characterised by a previously unknown chromophore. Among twelve different species of scleractinians examined, leptopsammins were found to be present in only two genera, Leptopsammia and Dendrophyllia. 相似文献
100.
Durante la revisión de la familia Lamiaceae para el estado de Guerrero, se descubrió una especie nueva de Salvia, perteneciente al subgénero Calosphace. Se presenta la descripción y una ilustración de la nueva especie, Salvia diegoae, y se discuten los caracteres que la distinguen de las especies afines. Esta especie presenta flores totalmente blancas, color
poco común dentro del subgénero y se considera afín a Salvia leninae, de la sección Nivalis. 相似文献