Proceedings of the Japan Academy, Series B

Review

Discovery of naked charm particles and lifetime differences among charm species using nuclear emulsion techniques innovated in Japan

Kiyoshi NIU

2008 Volume 84 Issue 1 Pages 1-16
Published: January 30, 2008
Released on J-STAGE: January 09, 2008

DOIhttps://doi.org/10.2183/pjab.84.1

JOURNAL FREE ACCESS

Show abstractHide abstract

This is a historical review of the discovery of naked charm particles and lifetime differences among charm species. These discoveries in the field of cosmic-ray physics were made by the innovation of nuclear emulsion techniques in Japan. A pair of naked charm particles was discovered in 1971 in a cosmic-ray interaction, three years prior to the discovery of the hidden charm particle, J/Ψ, in western countries. Lifetime differences between charged and neutral charm particles were pointed out in 1975, which were later re-confirmed by the collaborative Experiment E531 at Fermilab. Japanese physicists led by K.Niu made essential contributions to it with improved emulsion techniques, complemented by electronic detectors. This review also discusses the discovery of artificially produced naked charm particles by us in an accelerator experiment at Fermilab in 1975 and of multiple-pair productions of charm particles in a single interaction in 1987 by the collaborative Experiment WA75 at CERN.

(Communicated by Toshimitsu YAMAZAKI, M.J.A.)

View full abstract

Download PDF (472K)

Original Papers

Molecular evolution of mitochondrial introns in the liverwort Marchantia polymorpha

Kanji OHYAMA, Miho TAKEMURA

2008 Volume 84 Issue 1 Pages 17-23
Published: January 30, 2008
Released on J-STAGE: January 09, 2008

DOIhttps://doi.org/10.2183/pjab.84.17

JOURNAL FREE ACCESS

Show abstractHide abstract

We here describe in detail the characterization and molecular evolution of group II introns in the mitochondrial genome of the liverwort Marchantia polymorpha. We find that 18 introns of the 25 group II introns can be assigned by their similarities to six clusters, indicating an intra-genomic propagation of one ancestral intron each into the respective clusters in the liverwort mitochondrial genome. Interestingly, the intra-genomic propagation of some of these introns occurred only after the evolutionary separation of the bryophytes from the other clades of plants. Finally we report that the maturase-like sequences in the liverwort group II introns have further evolved by horizontal and independent transposition and substitution by analogous sequences from other fungal introns.

(Communicated by Yasuyuki YAMADA, M.J.A.)

View full abstract

Download PDF (1001K)
Effect of nutritional substrate on sulfolipids metabolic turnover in isolated renal tubules from rat

Ken-ichi NAGAI, Keiko TADANO-ARITOMI, Yukio NIIMURA, Ineo ISHIZUKA

2008 Volume 84 Issue 1 Pages 24-29
Published: January 30, 2008
Released on J-STAGE: January 09, 2008

DOIhttps://doi.org/10.2183/pjab.84.24

JOURNAL FREE ACCESS

Show abstractHide abstract

Effects of a glycolytic (glucose) and a gluconeogenic renal nutritional substrate (glutamine) on metabolic turnover of sulfolipids, determined as [³⁵S]sulfate incorporation, were compared in renal tubules prepared from well-fed rats. The results showed that the effects of glucose and glutamine, at nearly physiological serum concentration, are quite contrary to each other. Glucose increased the turnover rates of relatively long chain ganglio-series sulfoglycolipids (Gg₃Cer II³-sulfate and Gg₄Cer II³,IV³-bis-sulfate) (1.7 to 2.4-fold), but not of cholesterol 3-sulfate (0.9-fold). In contrast, glutamine accelerated the turnover rates of relatively short chain sulfoglycolipids (glucosyl sulfatide, galactosyl sulfatide and lactosyl sulfatide) (1.3 to 2.7-fold), as well as cholesterol 3-sulfate (2.4-fold). The possible mechanism which causes these marked differences is also discussed.

(Communicated by Tamio YAMAKAWA, M.J.A.)

View full abstract

Download PDF (126K)

Register with J-STAGE for free!