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A. B. MUNKACSI S. KAWAKAMI J. J. PAN K. LEE S. STOXEN J. HANG G. MAY 《Molecular ecology resources》2006,6(1):221-223
It has been postulated that the fungus Ustilago maydis followed its host maize around the world. In order to understand the biogeography of this fungus relative to its host, we used a bioinformatics approach to develop 86 tandem repeat markers useful for population studies of U. maydis. We characterized repeat motifs between two and 155 nucleotides using 36 isolates from USA, Mexico and South America. Our data suggested that (i) repeat motif length does not predict the number of alleles for that locus, and (ii) that the more polymorphic markers can resolve differences in a small geographical area. 相似文献
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The responses of two aquatic plants, arrowhead (Sagittaria pygmaea Miq.) and pondweed (Potamogeton distinctus A. Benn), to anoxia were compared with those of rice (Oryza sativa L.). Shoot elongation of arrowhead tubers was enhanced at around 1 kPa O2, whereas that of pondweed turions was slight in air and reached a maximum in the absence of O2. Anaerobic enhancement of alcohol dehydrogenase (ADH) activity took place in rice coleoptiles but not in arrowhead and pondweed shoots. Shoots of both arrowhead and pondweed maintained a more stable energy status than did the rice coleoptile under anaerobic conditions. Total adenylate nucleotide contents of arrowhead and pondweed shoots were constant under anaerobic conditions. Adenylate energy charge in both shoots remained at a high and stable level of more than 0·8 for at least 8 d. Three forms of ADH from arrowhead shoots were separated by starch gel electrophoresis, showing that the activity of each ADH form was different under aerobic and anaerobic conditions. The incorporation of 35S-labelled Cys and Met into soluble proteins in arrowhead shoots showed active protein biosynthesis and an involvement of a special set of polypeptides in the anaerobiosis. 相似文献
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MASASHI URABE TADATAKA KAWAKAMI YUKIO IGUSA SHUN-ICHI MIYAZAKI 《Development, growth & differentiation》1985,27(1):41-50
Cell adhesion and fusion were found to occur in zona-free hamster eggs placed in contact and then inseminated. A cytoplasmic fusion occurred in 7% of paired eggs mainly between 10 and 50 min after insemination. All other eggs that failed to fuse adhered tightly to one another within about 1 hr. Electrophysiological monitoring of the fusion process revealed that an electrical coupling (EC) suddenly appears between apposed eggs and completed within 2–15 min as the first step of cell fusion. Periodic hyperpolarizing responses (HRs), which have been found previously in fertilized hamster eggs to reflect a periodic increase in cytoplasmic Ca2+ ions, become gradually synchronized and completely coincide in paired eggs 10–30 min after the establishment of EC. Thus the paired eggs become an electrically single cell as the second step. Then the boundary between the eggs breaks down, resulting in formation of a single, spherical egg in several minutes. On the other hand, most of adhered eggs showed neither EC nor synchronization of HRs. Some adhered eggs showed only a low efficiency EC. 相似文献
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