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Volume 33, Issue 2
Displaying 1-11 of 11 articles from this issue
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Naoki SUGIMOTO1993 Volume 33 Issue 2 Pages 61-67
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSStructure and function of nucleic acids are well known to be dependent on their base sequences. Current predictions of the structure stability of nucleic acids from thermodynamic parameters for formation of base pairs depend largely on a nearest neighbor model. However, it has not been tested whether the published values of the nearest neighbor parameters for DNA are valid. In this paper, the published parameters are discussed, new parameters are present, and the new ones are applied to the prediction of the mechanism of the recombination and dissociation of DNA double helices.View full abstractDownload PDF (2332K) -
Mitsuhiro SHIMIZU, Heisaburo SHINDO, Ushiho MATSUMOTO1993 Volume 33 Issue 2 Pages 68-73
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSTwo types of DNA triplexes, intra-and intermolecular triplexes, at polypurine·polipyrimidine segments in both recombinant plasmids and DNA fragments were identified and characterized recently: the former forms in supercoiled plasmids, and the latter forms by combining duplex DNA and a single-stranded oligomer. These findings brought the research on the triplestranded DNA and RNA polymers discoverd 35 years ago into new phase. The possible biological significance of triplexes has been suggested by the fact that polypurine·polypyrimidine sequences are overrepresented in eukaryotic genomes and often are found near genes and recombinational hot-spots. The structural properties and biological implications of DNA triplexes are described.View full abstractDownload PDF (3371K) -
Satoru TOKUTOMI1993 Volume 33 Issue 2 Pages 74-80
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSMolecular structure and molecular mechanism of photoreception of phytochrome, a photoreceptor for morphogenetic responses in green plants, are reviewed. In the first half, domain structures are discussed based on their proteolytic sites, phosphorylation sites, dimerization sites, e. t.c. And recent topics related to their possible functions, e.g. transmitter module of bacteria sensor protein, ATP-binding motif analogue, are summerized. In the second half, the quartenary molecular and the chromophore structures are discussed based on small-angle Xray scattering and resonance Raman scattering, respectively, and the molecular mechanism of polarotropic responses analyzed based on linear dichroism of oriented phytochrome preparations is discussed.View full abstractDownload PDF (3412K) -
Application to Photoisomerization Dynamics of RhodopsinToshiaki KAKITANI, Yasuyo MAEKAWA1993 Volume 33 Issue 2 Pages 81-86
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSBy the analysis of the Fourier transformation of optical absorption spectrum (FTOA) of rhodopsin, we elucidate how the wavepacket starting from the Franck-Condon state in the excited state propagates along the potential energy surface in the excited state and when the w avepacket transits to the ground state. It is found that the photoisomerization to photorhodopsin takes place in 170fs, in good agreement with the value 200fs which was recently obtained by the femtosecond spectroscopic experiment. The potentiality of the FTOA method to analyze the detailed mechanism of the excited state dynamics is discussed.View full abstractDownload PDF (1506K) -
Tatsumi NAGAHAMA1993 Volume 33 Issue 2 Pages 87-93
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSFood stimili elicit a characteristic "feeding posture", in which the animal lifts the head and relaxes the anterior part of the foot. A pair of cerebral neuron, C-PR, may function as an important element that evokes a food-arousal state. The C-PR may also mediate the feeding posture by exciting or inhibiting many types of body postural motor neurons. In addition, it has longlasting modulatory effects on the movements of the neck and the anterior foot, which were produced by the motor neurons. These effects may be caused by modulatory neurons receiving monosynaptic excitatory inputs from the C-PR.View full abstractDownload PDF (1350K) -
Naohiro YOSHIDA, Harunori OHMORI1993 Volume 33 Issue 2 Pages 94-98
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSHair cells receive efferent innervation of the inhibitory nature. The electrical stimulation to the efferent nerve made a long lasting and a large amplitude hyperpolarization in hair cells. Acetylcholine (ACh) is considered as the most likely candidate of the neurotransmitter of efferent synapse. In this issue, we describe the mechanism of ACh-induced hyperpolarization studied by the whole cell recording configulation and the Ca2+ sensitive fluorophotometric technique utilizing fura-2.View full abstractDownload PDF (1878K) -
Akira WADANO1993 Volume 33 Issue 2 Pages 99-104
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSComputer simulations of metabolic pathways should use a realistic models concerning parameters of enzyme kinetics, and cell dimensions. The enzyme parameters are well determined with a best fit method. And it had better that the models for the analyses of enzyme kinetics is selected on the basis of AIC. Computer simulation of metabolic pathways is a convenient tool for the elucidation of control coefficients. The control coefficient is more quantitative concept to represent a flux control than limiting step is.View full abstractDownload PDF (1446K) -
Michihiro IMAMURA1993 Volume 33 Issue 2 Pages 105-110
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSWe have recently purified a novel nonmuscle α-actinin from chicken lung [Imamura and Masaki (1992) J. Biol. Chem., (1992) 267, 25927-25933. in. press]. This lung α-actinin has Ca2+ -sensitivity for interaction with F-actin. However, even in the presence of Ca2+, its actin-gelation activity was much higher than that of Ca2+-insensitive muscle-type α-actinin. Proteolytic cleavage analysis and the primary structure deduced from nucleotide sequence of cDNA showed that the lung α-actinin has structural divergence at COOH-terminal region that indudes Ca2+-binding EF-hand motifs. This suggests that the low Ca2+-sensitivity of the lung α-actinin is ascribed to the structural divergence.View full abstractDownload PDF (1833K) -
Masayuki TOKITA1993 Volume 33 Issue 2 Pages 111-116
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSWhen water passes through a polymer gel, a frictional resistance arises between the water and the polymer network of gel. If the network is permanently crosslinked, it is natural to assume that the friction, normalized by the viscosity of water, shouid be independent of temperature. We found, however, that the friction decreases reversibly by three orders of magnitude and appears to diminish as the gel approaches a certain temperature, This phenomenon occurs in spite of the fact that the network structure and the total volume of the gel, thus the average density of the network, are unchanged.View full abstractDownload PDF (1718K) -
Masato KINOSHITA, Kenjirou OZATO1993 Volume 33 Issue 2 Pages 117-119
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSDownload PDF (1214K) -
[in Japanese], [in Japanese]1993 Volume 33 Issue 2 Pages 120-123
Published: March 25, 1993
Released on J-STAGE: July 09, 2009
JOURNAL FREE ACCESSDownload PDF (284K)
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