Hiroe Hayashi

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A transferred DNA (T-DNA) tagging vector with the potential to produce dominant mutations was used with cocultured Agrobacterium tumefaciens and protoplasts to tag genes involved in the action of the plant growth substance auxin. Transgenic calli were selected for their ability to grow in the absence of auxin in the culture media. From one experiment, 12(More)
The characteristics of Agrobacterium-mediated plant transformation are such that the T-DNA can be used as an insertional mutagen and, by extension, a gene tag. An increasing number of mutants have been obtained as a result of T-DNA insertion and the versatility of this experimental system can be exploited further to tag sequences of DNA which control gene(More)
We describe the characterization of axi 1, a tobacco gene isolated by activation T-DNA tagging which apparently plays a role in auxin action. Upon deregulated expression, axi 1 confers on protoplasts the ability to grow in culture not only in the absence of auxin but also in high auxin concentrations where maximal frequencies of cell division are not(More)
We identified and analyzed a DNA region that is required for the stable maintenance of plasmids in the genus Sphingomonas. This DNA fragment, a 244 bp, is localized in the upstream region of the repA gene of low-copy-number small plasmid pYAN-1 (4896 bp) of Sphingobium yanoikuyae. It has four inverted repeats and one direct repeat for possible secondary(More)
The sunlight that reaches the surface of the earth is composed of polychromatic light with wavelengths ranging from 290 nm to 2500 nm. Ultraviolet (UV) light is a component of sunlight that is harmful to organisms. Although it is known that sunlight induces photoproducts and harmful eŠects such as major DNA damage caused by UV light in the tissues of many(More)
We have identified and analyzed two DNA regions responsible for stable maintenance of a plasmid in the genus Sphingomonas and Escherichia coli. A 37 bp fragment, upstream of the repA gene, is required for stable maintenance of the low-copy-number small plasmid pYAN-2 (4,687 bp) from Sphingobium yanoikuyae. It does not encode any significant protein sequence(More)
  • Hiroe Hayashi
  • [Hokkaido igaku zasshi] The Hokkaido journal of…
  • 1985
The development of teratomas and yolk sac tumors from displaced yolk sac is well documented in rats and mice. However, precise mechanisms of induction and pathogeneses of these tumors still remain unknown. The present study was undertaken in order to elucidate whether this phenomenon is common to all rodents, to identify the origin of these tumors and to(More)
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