著者

Matsunaga Wataru Kobayashi Akie Kato Atsushi ITO Hidetaka

出版者

Oxford University Press

雑誌

Plant and cell physiology (ISSN:00320781)

巻号頁・発行日

vol.53, no.5, pp.824-833, 2012-05-01

参考文献数

44

被引用文献数

4 65

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Environmental stress influences genetic and epigenetic regulation in plant genomes. We previously reported that heat stress activated a copia-like retrotransposon named ONSEN (Ito et al., 2011). To investigate the heat sensitivity and transgenerational activation of ONSEN, we analyzed the stress response by temperature shift and multi-treatments of heat stress. ONSEN was activated at 37℃, and the newly inserted ONSEN was transcriptionally activate and mobile to the next generation subjected to heat stress, indicating that the regulation of ONSEN is independent from positional effects on the chromosome. Reciprocal crosses with activated ONSEN revealed that the transgenerational transposition was inherited from both sexes, indicating that the transposition is suppressed independent of gametophytic regulation. We showed previously that ONSEN was transposed in mutants deficient in siRNA biogenesis, including nrpd2 and rdr2, but not dcl3. To define the functional redundancy of DCL proteins in Arabidopsis, we analyzed ONSEN activation in mutants deficient in Dicer-like proteins, including dcl2, dcl3 and dcl4. ONSEN was nearly immobile in a single Dicer mutant; however, some transgenerational transpositions were observed in dcl2/dcl3/dcl4 triple mutants subjected to heat stress. This indicated that the Dicer family is redundant for ONSEN transposition. To examine the activation of ONSEN in undifferentiated cells, ONSEN transcripts and synthesized DNA were analyzed in heat-stressed callus tissue. In contrast with vegetative tissue, high accumulation of the transcripts and amplified DNA copies of ONSEN were detected in callus. This result indicated that ONSEN activation is controlled by cell-specific regulatory mechanisms.

著者

Kato Atsushi Kuroda Masaaki

出版者

社団法人日本動物学会

雑誌

Zoological science (ISSN:02890003)

巻号頁・発行日

vol.21, no.12, 2004-12-25

著者

Ito Hiroshi Maeda Tetsuhiko Nakano Akihiro Hwang Chul Min Ishida Masayoshi Kato Atsushi Yoshida Tetsuya

出版者

Elsevier Ltd.

雑誌

International journal of hydrogen energy (ISSN:03603199)

巻号頁・発行日

vol.37, no.9, pp.7418-7428, 2012-05

被引用文献数

132 11

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Experimentalstudy on proton exchange membrane (PEM) electrolyzer was carried out focusing on the effect of pore structural properties of currentcollectors, such as porosity and pore diameter. Various titanium (Ti)-felt substrates with different porosities and pore diameters (measured by capillary flow porometry) were used as the anode currentcollector. Results show that when the mean pore diameter of the currentcollector was larger than 10 μm, the electrolysis performance improved with decreasing pore diameter. In contrast, changes in porosity had no significant effect on the cell performance when the porosity exceeded 0.50. The flow pattern of two-phase flow in the flow channel was discussed in terms of its relationship to bubble size and to pore diameter of the currentcollector. Finally, correlation between the calculated membrane resistance and the measured pore diameter of the currentcollectors suggest that larger bubbles generated from larger pores tend to become long bubbles in the channel, thus hindering the water supply to the membrane.