Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 75 , Issue 6
Showing 1-14 articles out of 14 articles from the selected issue
  • Hisatoshi BABA, Mamoru KAWAZOE, Toshi ASADA
    1999 Volume 75 Issue 6 Pages 107-111
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    It has been reported by many authors that the number of pulse-like electromagnetic signals per unit time increases in the LF, VLF and HF ranges during the period of several days preceding the occurrence of an earthquake in land or under shallow sea close to land. However, with the reported observations whether or not these signals originate in the epicentral area is not clear, because in most cases the epicenter-to-receiver distances are many tens of kilometers or more. We have conducted an experiment to directly detect the electromagnetic emissions from earthquake source by making radio-noise observation in conjunction with aftershocks of the 17 January 1995 Hyogo-ken Nanbu (Kobe) earthquake. The motivation behind this attempt was to investigate if the aftershocks of very small S-P times are accompanied by a type of electromagnetic signals different from those usually observed in association with distant large earthquakes. Observations were made from 21 to 27 January 1995, using radio receivers. During this period, 804 aftershocks were recorded. In 128 of these aftershocks, the S-P time was shorter than 0.7sec, or the hypocentral distance was less than approximately 3.5km. Further, 53 cases of these 128 aftershocks were accompanied by electromagnetic signals lasting approximately 1.5 to 4.0min. Since the correlation between the occurrences of electromagnetic signals and aftershocks was found to be high, the two phenomena can be considered to have a physically close relationship.
    Download PDF (871K)
  • Takahiro SHIOKAWA, Junji SHIMODA, Akimasa MASUDA
    1999 Volume 75 Issue 6 Pages 112-116
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Based on the data published by Elderfield and Greaves (1982) for a water column at a site, GEOSECS station 115, of northeastern Atlantic (28°N 26°W), the light-lanthanide tetrad effect was evaluated by the method developed by Masuda and his collaborators. The extent of variation of this effect is much larger than those observed in Pacific and Indian Oceans. Meanwhile, it intrigues us that the value for the effect in question at the top of the water column is almost the same as that at its bottom. Similar facts are observed generally at water columns of other oceans studied thus far. Features of dependence of Nd concentration on depth and of dependence of Ce and Eu anomalies evaluated on the basis of the same mathematical method are also discussed. A minimum absolute value of negative aberration extremum defining the tetrad effect at station 115 can be ascribed to the outflow from the Mediterranean Sea.
    Download PDF (630K)
  • Shuichi MATSUMURA, Satoshi HARAI, Kazunobu TOSHIMA
    1999 Volume 75 Issue 6 Pages 117-121
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Diethyl carbonate and 1, 4-butanediol were polymerized using lipase at a temperature between 70 and 75°C to yield poly(tetramethylene carbonate) in a successive two-step polymerization. Bulk polymerization, especially at a temperature between 70 and 75°C, and preferably using immobilized lipase from Candida antarctica (Novozym 435) gave poly(tetramethylene carbonate) with a weight-average molecular weight of greater than 40, 000.
    Download PDF (626K)
  • Jian Ping GONG, Yoshiyuki IWASAKI, Go KAGATA, Yoshihito OSADA
    1999 Volume 75 Issue 6 Pages 122-126
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The sliding friction of various kinds of hydrogels has been studied and it was found that the frictional behaviors of the hydrogels do not conform to Amonton's law FW, which well describes the friction of solids. The frictional force and its dependencies on the load are quite different depending on the chemical structures of the gels, surface properties of the opposing substrates, and the measurement condition. The gel friction is explained in terms of interfacial interaction, either attractive or repulsive, between the polymer chain and the solid surface. According to this model, the frictional force is ascribed to the viscous flow of solvent at the interface in the repulsive case. In the attractive case, the force to detach the adsorbing chain from the substrate appears as friction. Surface adhesion between glass particles and gels measured by AFM showed a good correlation with the friction, which support the repulsion-adsorption model proposed by authors.
    Download PDF (630K)
  • Yoshiharu INOUE, Akira KIMURA
    1999 Volume 75 Issue 6 Pages 127-132
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Methylglyoxal is an endogenous cytotoxic compound formed as a byproduct of glycolysis. We systematically analyzed the metabolic fate of methylglyoxal in various microorganisms and found that glyoxalase I is a ubiquitous and critical enzyme for its detoxification. We found that glyoxalase I consists of five segments (regions I-V) which are conserved among the glyoxalase Is of various species. We hypothesize that yeast glyoxalase I evolved by gene duplication and here show supporting evidence. We also found that expression of the structural gene for the glyoxalase I of S. cerevisiae is induced by osmotic stress through the HOG-MAG kinase signaling pathway. We identified the physiological significance of this glycolytic-methylglyoxal pathway in S. cerevisiae.
    Download PDF (4045K)
  • Yuzuru SUZUKI
    1999 Volume 75 Issue 6 Pages 133-137
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The proline rule which was proposed as a general strategy for protein thermal stabilization [Suzuki, Y., Oishi, K., Nakano, H., and Nagayama, T. (1987) Appl. Microbiol. Biotechnol. 26, 546-551] has been examined and refined in the present study. The proline rule in refined form states that thermostability of a globular protein can be additively increased by increasing the frequency of the occurrence of proline residues in the second positions of β-turns (and in the first turns of α-helices or on coils) on the surface of the protein, and that the overall effect on thermostability can be further strengthened by clustering proline residues around flexible regions of the protein.
    Download PDF (4135K)
  • Toshihiko KAWACHI, Shigeya MAEDA
    1999 Volume 75 Issue 6 Pages 138-143
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    A stream water pollution control model based on the concept of the finite element and linear programming method (FE and LP method) is presented. The model considers a network of interconnected streams and two water quality constituents, biochemical oxygen demand (BOD) and dissolved oxygen (DO). The finite element method is used to cast BOD and DO transport equations into a system of linear algebraic equations which are directly employed as equality constraints of a linear programming problem. To evaluate some of the coefficients of those constraints, dynamic and continuity equations for steady-state gradually varied flow are solved by the Newton-Raphson method. Operating the model, an optimal allocation of BOD loads from outfalls in the stream network can be obtained. An application is made to a hypothetical network to demonstrate that the model could be a useful tool for stream water pollution control.
    Download PDF (791K)
  • Yukio KIHO, Christopher PALMER, Masami ITO, Tsuruji IWAI, Yoshio OKADA
    1999 Volume 75 Issue 6 Pages 144-149
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Modified trypsin (m-trysin) (essential amino acids for human in trypsin are neglected by replacing them with G (dummy)) was analysed by DEV model. It was found that the proteolytic functional system of trypsin could be assigned with m-trypsin and essential amino acids are not necessary in this step. Similar results were obtained with m-RNase and non-polar trypsin. These results suggest that the basic plan in the construction of trypsin or RNase can be made from non-polar or non-essential amino acids. The possible involvement of water is also discussed. Further discussion on the basic plan clarified the necessity for large DEV and DD values. Large DEV values for site B can be attained mainly by large n(z) values in formula [1] and are neutralized by large DD values from site E.
    Download PDF (770K)
  • Yukio KIHO, Yoshio OKADA, Tsuruji IWAI
    1999 Volume 75 Issue 6 Pages 150-155
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Near to the active sites of trypsin, the DEV model could predict the functional sites from which the proteolytic functional system of trypsin was defined. In the case of chymotrypsin, however, the assignment of functional sites failed. When some appropriate portion is removed from chymotrypsin, the functional system could be defined near the active sites. It is inferred that the proteolytic functional system of chymotrypsin is not independent of other portions of the molecule.
    Download PDF (732K)
  • Yukio KIHO, Christopher PALMER, Hiroyuki MORI, Yoshio OKADA, Tsuruji I ...
    1999 Volume 75 Issue 6 Pages 156-161
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    From sites B and E in the DEV model, a closed circuit can be made in which the active sites of trypsin are found. In the presence of a substrate, the hydrophobic amino acid sequence near to the cleavage site of the substrate enters into the trypsin closed circuit. This closed circuit is considered to be a channel for information transfer. Information transfer can start from anywhere in the molecule and enters into the closed circuit. The mode of transfer is unique to biological catalysis, in contrast to chemical catalysis which operates by a one way transfer of information.
    Download PDF (810K)
  • Michi-hiko OGATA
    1999 Volume 75 Issue 6 Pages 162-165
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Performance of the muscle is examined employing the self-excited oscillation analysis, which is useful to express the force-velocity relationship in muscle. What the present formula suggests is that when a muscle is activated, mechanical myoplasmic resistance initially drops, and then part of the contractile elements build up a tensile stress equal to tensile strain (load, p) while the rest part of these elements draw the load and shorten the muscle. The new formula is mathematically identical with Hill's equation, but utilizes only a single constant (β), which implies an important intrinsic property of muscle and is deserving of further investigation.
    Download PDF (490K)
  • Shin-ichi MAKINO, Naoki AMANO, Hideaki KOIKE, Masashi SUZUKI
    1999 Volume 75 Issue 6 Pages 166-171
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    By analyzing archaebacterial genomic DNA sequences, three new prophages have been found inserted in tRNA genes of the host genomes: proPOF1 and proPOF2 in the genome of Pyrococcus sp. OT3, and proMJF1 in that of Methanococcus jannaschii. The three prophages possess a gene coding for site-specific tyrosine integrase, and are characterized with pairs of elements of the same 46-65 base sequences, that are positioned on the borders to the host genomes (i.e. the attachments). If the two ends of proPOF1 are connected to form a circle by overlapping the two attachments, proPOF2 possesses 33 ORFs in 9 putative transcription units (i.e. 5 operons and 4 independently transcribed ORFs) in 4 clusters inside each of which the direction of transcription is kept the same. This prophage is more likely to inherit a potential to be activated to a phage than is proPOF2, which has only 3 ORFs. In proPOF1 and proPOF2 the attachments are designed, so that their nucleotide sequences are complementary to the 3'-terminal halves of the host tRNA genes. These attachments are part of the integrase genes in the prophages. Upon the integration the integrase genes were divided at the attachments into two segments and are positioned at the two ends of the prophages. In proMJF1 the integrase gene is undivided, and is positioned between the two attachments whose nucleotide sequence is the same as that of the 3'-terminal half of the host tRNA gene. Thus, the type of phage-integration that created proMJF1 is different from that created proPOF1 and proPOF2.
    Download PDF (972K)
  • Tetsuji HIRONAKA, Yoshio IKARI
    1999 Volume 75 Issue 6 Pages 172-175
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The true resting membrane potential and membrane action potential of crayfish giant axons were recorded with two external electrodes using a partition method in which the insulation grade was extensively improved by utilizing a water-absorbing particle mixed with vaseline and liquid paraffin, and the residual membrane potential at the lateral reference pool was removed by using an offset solution. The offset solution contained 10-4M of ouabain to block electrogenic sodium pump and a higher potassium concentration than that of the isotonic KCl solution. No short circuiting correction was necessary within an error of a few percent. Elimination of chloride ions from the offset solution substantially prolonged the surviving time of the preparation. This experimental system was developed to study a cell in as intact condition as possible, especially in a long-term experiment.
    Download PDF (550K)
  • Tetsuji HIRONAKA, Yoshio IKARI
    1999 Volume 75 Issue 6 Pages 176-180
    Published: 1999
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    A voltage-clamp system with internal perfusion for quasi-intact crayfish giant axons was developed using a partition method where three pools were formed by two partitions. The membrane potential was extracellularly recorded across the one side partition whose resistance was highly increased using a water-absorbing material, Sephadex G25 mixed with vaseline and liquid paraffin so that no short circuiting correction became necessary. Axon membranes were voltage-clamped at the center by feeding current through the other side pool. For the internal perfusion with the axoplasm left intact, the membranes of the lateral pools were perforated with a 0.1% of saponin-treatment for 1.5-2min, through which the axon was intracellularly“perfused”with a reasonable diffusion rate. This system was well bearable to long-term experiments under both extracellularly and intracellularly controlled conditions of the cell.
    Download PDF (900K)
feedback
Top