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551.
Nuclear DNA sequences from late Pleistocene megafauna 总被引:6,自引:1,他引:5
We report the retrieval and characterization of multi- and single-copy
nuclear DNA sequences from Alaskan and Siberian mammoths (Mammuthus
primigenius). In addition, a nuclear copy of a mitochondrial gene was
recovered. Furthermore, a 13,000-year-old ground sloth and a 33,000-
year-old cave bear yielded multicopy nuclear DNA sequences. Thus, multicopy
and single-copy genes can be analyzed from Pleistocene faunal remains. The
results also show that under some circumstances, nucleotide sequence
differences between alleles found within one individual can be
distinguished from DNA sequence variation caused by postmortem DNA damage.
The nuclear sequences retrieved from the mammoths suggest that mammoths
were more similar to Asian elephants than to African elephants.
相似文献
552.
Influence of oxygen on phospholipid production and colony formation in a nitrogen-fixing mutant of Azotobacter vinelandii.
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Colony dimorphism in a conditional nitrogen-fixing mutant of Azotobacter vinelandii was directly influenced by fixed nitrogen and oxygen partial pressure and may be related to the production of internal peripheral membrane. 相似文献
553.
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555.
Avoidance of precipitation and carbohydrate breakdown in autoclaved plant tissue culture media 总被引:2,自引:0,他引:2
The extent of breakdown of fructose and glucose derived from sucrose in the medium of Murashige and Skoog (1962) during autoclaving was investigated by polarographic measurement. Although not present in the original MS medium but often used in place of FeSO4 + Na2-EDTA, FeNa-EDTA was found to be primarily responsible for catalyzing the breakdown of these monosaccharides. It would therefore be good practice to autoclave FeNa-EDTA separate from the carbohydrate constituents of the medium in order to reduce the formation of toxic substances derived from the latter's breakdown. Autoclaving FeNa-EDTA separately has the additional advantage of preventing precipitation of certain micronutrient elements. Further precipitation can be avoided by autoclaving FeNa-EDTA and KH2PO4 together, but separately, from other components of the medium. By eliminating precipitation and minimizing the breakdown of monosaccharides during autoclaving, it is possible to improve the quality of the medium without resorting to sterilization by filtering.Abbreviations HMF
5-(hydroxymethyl)-2-furaldehyde
- FeNa-EDTA
ferric monosodium ethylenediaminetetraacetic acid
- MS
Murashige and Skoog
- NAA
naphthylacetic acid 相似文献
556.
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558.
Eric A. Schenk Charles Churukian Charles Willis Elmer Stotz 《Biotechnic & histochemistry》1983,58(6):377-379
In 1980, eosin Y was the certified dye with which technologists encountered most problems. The specific problem most frequently brought to the attention of the Biological Stain Commission was that solutions of eosin Y formed a precipitate and failed to stain cytoplasm red when used as a counterstain to hematoxylin. 相似文献
559.
Christoph Koffler Jon Dettling Cashion East Matthias Finkbeiner Sergio F. Galeano Roland Geyer Mark J. Goedkoop Troy R. Hawkins Connie D. Hensler Arpad Horvath Sebastien Humbert Scott M. Kaufman Amy E. Landis Lise Laurin Pascal Lesage Manuele Margni Ken Martchek H. Scott Matthews Jamie K. Meil Gregory Norris Rita C. Schenk Thomas P. Seager Maureen Sertich Greg Thoma Casey Wagner 《The International Journal of Life Cycle Assessment》2013,18(2):302-305
560.
P Fritz J Hoenes J Schenk A Mischlinski A Grau J G Saal H V Tuczek H Multhaupt G Pfleiderer 《Histochemistry》1986,85(3):209-214
We describe an improvement of the immunogold technique, which is based on the colour development of silver-intensified immunogold signals. This method (referred to as the coloured-SIG technique) was found to be as sensitive as the silver-intensified immunogold method and more sensitive (in two of the three tested systems) than immunoenzymatic procedures, such as the peroxidase/antiperoxidase technique or the avidin-biotin system. The coloured SIG-method results in either a magenta-red or a cyan-blue final reaction product. Therefore, this new improvement of the immunogold technique should be useful in double-staining methods, immunoblot methods and conventional immunostaining methods. 相似文献