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Volume 15 (1975)
- Issue 6 Pages 277-
- Issue 5 Pages 229-
- Issue 4 Pages 153-
- Issue 3 Pages 101-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 15, Issue 4
Displaying 1-5 of 5 articles from this issue
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Toshio MITSUI, Toshiaki HAMANAKA1975 Volume 15 Issue 4 Pages 153-163
Published: July 25, 1975
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSA review is made on recent development in X-ray diffraction studies on lipid and biological membranes.
The exposure or counting time needed to observe diffraction pattems from membranes has been very much shortened by the combined use of total reflection mirror, the curved monochromator and the position sensitive proportional counter. The time will be further shortened to the order of msec by use of the electron synchrotron radiation as a very strong X-ray source.
Discussion is made on what can be achieved with the new techniques by presenting several examples, concerning structures, phase transitions and phase separations in membranes and inter-membrane interactions. Recent activities in X-ray studies of biomembranes are summarized in a table.View full abstractDownload PDF (2021K) -
1975 Volume 15 Issue 4 Pages 163
Published: 1975
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSDownload PDF (37K) -
Shigeo IWAYANAGI, Yoshihiko SUGIURA1975 Volume 15 Issue 4 Pages 164-170
Published: July 25, 1975
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSThis review discusses the structural role of phospholipids in biological membranes. Phospholipids in an aqueous environment exhibit both thermotropic and lyotropic polymorphism. Most important is the smectic mesophase or the lamellar phase consisting of bimolecular layers of lipid molecules separated by layers of water. The bilayers of the lamellar phase exhibit a crystalline-to-liquid crystalline phase transition caused by changes in temperature, pH or ionic environment, as detected by X-ray diffraction, calorimetry and dilatometry. The lipid phase transition is a "melting" transition of the lipid hydrocarbon chains without disruption of two-dimensional networks formed by the hydrophilic group of the lipid molecules. The physiological relevance of the liquid crystalline state of lipids in cell membranes is pointed out.View full abstractDownload PDF (1930K) -
Hachiro INOKUCHI1975 Volume 15 Issue 4 Pages 171-183
Published: July 25, 1975
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSReplication and its control in lambda are reviewed in the framework of the replicon hypothesis. The experiments and arguments presented here give evidences that: (1) the N product acts in replication only by controlling the levels of the O and P products. (2) The O product controls positively theis replicon at the initiation step. (3) A new mutant, tiny 12, demonstrates that the replicator is a single structure and allows a high-resolution mapping of it. (4) Replication at an early stage is bidirectional, The characteristic linear polymer DNA molecules found at the late stage are discussed. (5) Transcription of the x-o-p region stimulates the initiation process not by leading to the synthesis of a protein, but by modifying the structure or cellular location of the replicates.View full abstractDownload PDF (718K) -
Hideaki NAKASHIMA1975 Volume 15 Issue 4 Pages 184-193
Published: July 25, 1975
Released on J-STAGE: May 25, 2009
JOURNAL FREE ACCESSCircadian rhythms are known with many organisms from single-celled flagellates to higher plants and animals. However, a relatively small number of circadian rhythms have been investigated in enough detail. The characteristics of the circadian rhythms were mentioned mainly aobut the rhythms of the common bean, Phaseolus, and of Gonyaulax. The most striking thing about the circadian rhythms is their uniformity between different organisms and temperature independence of the period length. Although the models were constructed by a number of investigators, the mechanism of the time-measuring system of the rhythm is unknown at now.
It was discussed lastly about Bunning's proposal that the same timing mechanism as the circadian rhythms is responsible for photoperiodic timing.View full abstractDownload PDF (2547K)
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