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Volume 17 (1977)
- Issue 6 Pages 277-
- Issue 5 Pages 229-
- Issue 4 Pages 181-
- Issue 3 Pages 121-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
Volume 17, Issue 2
Displaying 1-5 of 5 articles from this issue
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Hiroshi ASHIDA, Kohkichi KAWASAKI, Mumay TANSKY1977 Volume 17 Issue 2 Pages 69-82
Published: March 25, 1977
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSEcosystem is treated as an energy transducer, the input of which is solar radiation and the output is thermal energy. Three approaches from three different aspects of the ecosystem, structure, stability and efficiency are applied and developed. The most of the part [I] concerns to structure, where a new graphical index that measures quantitatively the food web structure is introduced. The last section of the part [I] and the whole of the part [II] are devoted to the stability, where after a concise review of the stability theorems, fairly powerful stability criteria with respect to the looped and nonlooped food webs are given in detail and furthermore the stability of the spatial distribution is discussed. As to the efficiency, a new treatment is proposed and developed all over this article, especially in part [III], which insists that the time change of the ecosystem is divided into two processes, one of which is dynamical process during short time scale and the other is successional process during long time scale, and that the successional process proceeds so as to minimize the Margalef's gross turn over rate. According to this new treatment, various quantities of model system are calculated and compared with the field data of Silver Springs by Odum.View full abstractDownload PDF (601K) -
Yoshifumi TAKEDA1977 Volume 17 Issue 2 Pages 83-95
Published: March 25, 1977
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSRequirement of Mg2+ in aminoacyl-tRNA formation has been well established. Replacement of Mg2+ requirement by various cations, such as Mn2+, Ca2+, Co2+, K+ and NH+4 has also been reported. Polyamines, such as spermine, spermidine and putrescine, could also replace Mg2+ requirement in several aminoacyl-tRNA formations.
The role of these cations in the reaction was studied and it was found that these cations played two distinct roles; that is, (1) to bind to tRNA to activate it to be charged with amino acids, (2) to bind tightly to aminoacyl-tRNA synthetase, probably at its active center, which is necessary for the enzyme to be active. Mg2+ could play both the role (1) and (2), whereas polyamines could play the role (1). Mn2+ seemed to be very important to play the role (2).
Concerted mechanism of aminoacyl-tRNA formation in the presence of polyamines is also discussed.View full abstractDownload PDF (608K) -
Yuichiro MAEDA, Naoto YAGI, Ichiro MATSUBARA1977 Volume 17 Issue 2 Pages 96-108
Published: March 25, 1977
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSLow-angle X-ray diffraction patterns were recorded from crab leg muscles in living resting state and in rigor (glycerol-extracted). Both resting and rigor patterns showed a series of layer lines arising from helical arrangement of actin subunits in the thin filaments. In the resting state, the cross-over repeat of the long-pitch actin helices was 36.6nm, and the symmetry of the genetic actin helix was an intermediate between 26/12 and 28/13. When the muscle went into rigor, the cross-over repeat changed to 38.2nm and the helical symmetry to 28/13, with no detectable change in the axial repeat of actin subunits.
In the rigor pattern, twelve other reflections were observed on the meridian and in the near-meridional region. These were indexed as orders of 2×38.3nm and could be assigned to troponin molecules; the meridional intensity peaks at even orders, the near-meridional intensity peaks at odd orders, and absence of the 12th, 14th and 16th orders could be explained by the model proposed by Ohtsuki (1974) for the arrangement of troponin molecules in the thin filaments. The pattern obtained from resting muscle showed several reflections assignable to troponin molecules; the positions of these reflections could also be explained by the Ohtsuki's model.View full abstractDownload PDF (2477K) -
[in Japanese], [in Japanese]1977 Volume 17 Issue 2 Pages 109-110
Published: March 25, 1977
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSDownload PDF (91K) -
[in Japanese]1977 Volume 17 Issue 2 Pages 111-114
Published: March 25, 1977
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSDownload PDF (293K)
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