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231.
Summary Recent availability of stable and well characterized selectable markers and ability to combine alien genomes parasexually have contributed to the development of molecular biology in higher plants, including gene expression and genetic manipulation.Several types of biochemical mutants (resistant to inhibitory concentrations of aminoacid(s) or aminoacid analogs as well as deficient for enzyme activity) have recently been isolated and characterized biochemically and genetically. Among them, mutants with alterations in the nitrogen and aminoacid metabolism, or in the activity of alcohol dehydrogenases are being used in the development of more efficient techniques of gene transfer.The manipulation of whole genomes by sexual or somatic cell fusion offers new potential in this field, but refinement of transfer techniques is desirable. The new set of selectable markers obtained through advanced cellular technology, as well as our ability to regenerate plants from manipulated cell lines are expected to play a major role in cellular engineering. 相似文献
232.
Seligy VL Barbier JR Dimock KD Dove MJ Moranelli F Morosoli R Willick GE Yaguchi M 《Biotechnology advances》1984,2(2):201-216
New gene selection techniques (Recombinant DNA) are currently available to exploit useful properties of various biological systems hitherto regarded as interesting but of little or no immediate commercial value. The application of genetic engineering techniques to problems in the Pulp and Paper Industry are many. As a first step these techniques are being used to provide much needed fundamental information on the cellular and molecular mechanisms involved in the expression of extra-cellular enzymes that degrade lignocellulosic pulping wastes. The information gleaned from the studies on cellulolytic fungi and bacteria can be used to genetically engineer a yeast or bacterium capable of converting pulping wastes into ethanol and other useful by-products. 相似文献
233.
G. D. Haffner 《Hydrobiologia》1977,54(3):225-231
Seston size distribution was determined with a Coulter Counter to investigate seston interaction and its effects on phytoplankton
production. Spatial distribution patterns of the non-productive component of the seston were as complex as those commonly
associated with algae. Seston might interact influencing production by changes in optical depth, abrasive actions and nutrient
adsorption. 相似文献
234.
N. Saha R. A. Bayoumi F. S. El Sheikh A. P. W. Samuel I. El Fadil I. S. El Houri Z. A. Sebai H. M. A. Sabaa 《American journal of physical anthropology》1980,52(4):595-600
A total of 292 randomly selected subjects belonging to two indigenous Arab tribes (Harbi and Ghamid) and two immigrant tribes (Mograbi and Mowallad), residents in Western Saudi Arabia, have been tested for genetic variants of six blood groups, four serum proteins, and five red cell enzyme systems. The distribution of the polymorphic systems was different between indigenous and immigrant tribes, and the present Arab population shows a considerable degree of admixture from the surrounding countries, in particular Africa. 相似文献
235.
The nature and distribution of hemotypes constituted by electrophoretic phenotypes in six loci, in a group of 183 Camargue horses, have been compared with those of five breeds of horses and ponies. The genetic similarities have been observed mainly with New Forest and Haflinger ponies, less with Barbs and Thoroughbreds, and the least with Arab horses. 相似文献
236.
237.
Leon R. Kass 《In vitro cellular & developmental biology. Plant》1981,17(12):1091-1099
Summary Modern science, dedicated since its 17th Century origins to the mastery and possession of nature for the relief of man's estate,
is a source of great social change, affecting our opinions, practices, and ways of life. It thus exists necessarily in tension
with law and morality, our institutions of stability and order. This tension between change and permanence, between science
and law or morals, was institutionalized by the American Founders who sought to encourage, under law, the progress in science
and the useful arts, by means of the copyright and patent laws. American science and technology have flourished under the
patent law, an ingenious ethical and social contract between scientists and the polity, through which private right and interest
and public good generally coincide. Nevertheless, this contract has its limitations. Some of these limitations are vividly
seen through the recent Supreme Court decision (in the Chakrabarty case) to permit the patenting of living microorganisms.
Analysis of this case shows why the contract between science and the polity embodied in the Patent Laws may not always serve
the public good and may also be harmful to science itself. Also, permitting ownership of living species shows how close we
have come in our thinking to overstepping the sensible limits of the project for the mastery and possession of nature. 相似文献
238.
A. L. Goldstein J. E. Palmer P. R. Johnson 《In vitro cellular & developmental biology. Plant》1981,17(8):651-655
Summary Primary fetal hepatocytes derived from Zucker rats with expectedfa gene frequencies of 0.0 and 0.75 have been established and can be used to detect early effects of thefa gene on hepatocellular metabolism. Paired incubation experiments demonstrate that protein synthesis in 0.75fa gene cultures is significantly less than in 0.0fa gene cultures under basal conditions. Insulin stimulates protein synthesis in 0.0fa gene cultures but has no effect on 0.75fa gene cultures. Cycloheximide inhibits protein synthesis in both types of culture. NH4Cl inhibits protein synthesis in 0.0 but not in 0.75fa gene cultures. These data suggest that fetal hepatocytes bearing thefa gene have in vitro a generally sluggish anabolic capacity and a blunted capacity to respond to insulin compared to fetal
hepatocytes without thefa gene. These diminished capacities may be expressions of a genetic error in lysosomal function.
A portion of this work was presented in preliminary form at the 1980 meeting of the Tissue Culture Association.
This work was supported in part by National Institutes of Health Grants AM19382 and AM06197. 相似文献
239.
Geographic variation and genetic aspects of reproductive diapause in Drosophila triauraria and D. quadraria 总被引:1,自引:0,他引:1
MASAHITO T. KIMURA 《Physiological Entomology》1983,8(2):181-186
ABSTRACT. Geographic variation and genetic aspect of reproductive diapause were studied in Drosophila triauraria Bock & Wheeler and D. quadraria Bock & Wheeler, in relation to their quantitative response to photoperiods. D. quadraria from the subtropical region had no photoperiodic diapause. In D. triauraria strains, diapause was induced under LD 10:14 or 12:12, but not under LD 14:10 or longer photoperiods. Their diapause was induced more effectively and maintained longer by LD 10:14 than by LD 12:12. The duration of diapause was longer in a northern strain, but the diapause inducing process varied little among different geographical strains. Diapause incidence was 50% or lower in F1 hybrids between D. triauraria and D. quadraria and backcross progenies between F1 and D. quadraria , and about 70% in backcross progenies between F1 and D. triauraria under LD 10:14, but very low under LD 12:12. The lower incidence of diapause in these F; and backcross progenies is assumed to be due to the less efficient induction of diapause, since once diapause was induced in them, it was maintained for a long time, especially in the backcross progenies between F1 and D. triauraria. These experiments suggest that diapause induction and maintenance are different physiological processes controlled by different genetic systems. 相似文献
240.
Molecular cloning of bovine leukemia virus DNA integrated into the bovine tumor cell genome 总被引:3,自引:0,他引:3
The bovine leukemia virus (BLV) DNA harbored in the bovine tumor cell genome was cloned in lambda Charon 4A phage. Using either representative or 3' half-enriched BLV cDNA as a blot hybridization probe, clone lambda BLV-1 was shown to carry 9 kb of the BLV genome, flanked by cellular sequences at both ends. Restriction mapping with twelve endonucleases and hybridization of the DNA fragments to BLV cDNA representing a 3'-end portion of the viral genome revealed the presence and precise location of two long terminal repeats (LTRs) and virus-cell junctions. Thus, lambda BLV-1 appears to contain the complete BLV genome and flanking tumor cellular sequences. The restriction map of the cloned BLV proviral DNA closely resembles that previously reported for unintegrated linear proviral DNA, but differs significantly from that of the integrated provirus of another BLV isolate, the difference occurring preferentially in the putative gag and pol genes. 相似文献