Seibutsu Butsuri

Interdigitated Structures in Phospholipid Membranes

Kazuo OHKI

1991 Volume 31 Issue 6 Pages 1-6
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_1

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Effects of ethanol on phosphatidylcholine dispersions have been investigated with an automated scanning density meter. On increasing the ethanol concentration in the dipalmitoylphosphatidylcholine dispersions, an interdigitated gel phase appeared between the gel phase and the ripple phase. And substitution effect of hydrogen oxide by deuterium oxide has been examined on thermotropic transition between the interdigitated gel phase and the ripple phase of dihexadecylphosphatidylcholine. The mechanism is also discussed from a thermodynamical viewpoint.

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Solution structure of calmodulin

Mikio KATAOKA

1991 Volume 31 Issue 6 Pages 7-12
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_7

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Solution structures of calmodulin, a ubiquitous calcium-binding protein in all eukaryotic cells, and calmodulin-peptide complex have been studied by solution scattering techniques. Calmodulin in solution possesses an elongated dumbbell shape, generally consistent with the crystal structure. A target peptide, such as melittin, mastoparan or MLCK-I, induces a large, calciumdependent conformational change in calmodulin. The overall shape of calmodulin-peptide comlex is globular. Using of the deletion mutants of calmodulin, we have revealed that the central linker region retains a predominantly α-helical conformation even in solution. A twisting motion would be a key step for the flexibility, as well as the bending. The globular structure is not a only possible conformation for the calmodulin-peptide complex. Some peptides form dumbbellshaped complexes with calmodulin.

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The Superoxide-forming Enzymatic System of Phagocytes

Hirotada FUJII

1991 Volume 31 Issue 6 Pages 13-19
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_13

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The generation of superoxide and oxygen-derived free radicals by the phagocytes (neutrophils, monocytes and macrophages) is catalyzed by a membrane-bound NADPH oxidase system which is dormant in resting cells and becomes activated during phagocytosis or by stimulating cells with suitable soluble stimulants. This oxidase system has been thought to be an electrontransport chain consisting of a flavoprotein, a b-type cytochrome (cytochrome b-558: cyt b-558) and cytosolic components (p47-phox, p67-phox and unknown factor). When activated, these components seem to act synergistically to form superoxide, but the roles of these components in the electron transport system are not fully elucidated.

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The role of humoral lectins of American cockroach on leg regeneration

Takeo KUBO, Kiyoshi KAWASAKI, Shunji NATORI

1991 Volume 31 Issue 6 Pages 20-26
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_20

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Three lectins named Periplaneta lectin, regenectin and 26kDa lectin were purified from the hemolymph of American cockroach Periplaneta americana. These lectins shared several common features: antigenicity, Ca²⁺ -dependency, subunit structure, and molecular shape, showing that they are members of a structural family. The participation of these lectins in leg regeneration was investigated by immunoblotting and immunofluorescence studies. Regenectin was found to appear transiently around developing muscle cells in the late stage of leg regeneration whereas 26kDa lectin was found outside the epidermis cells in the middle stage, suggesting that they play different roles in leg regeneration.

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Free Fitness that Always Increases in Evolution.

Yoh IWASA

1991 Volume 31 Issue 6 Pages 27-32
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_27

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Many dynamic models for evolution are Markovian and have "a free fitness function", which monotonically increases with time and takes its maximum at the evolutionary equilibrium. Free fitness is the logarithmic fitness plus entropy. Application to (1) molecular evolution model and (2) quantitative genetics are explained, and (3) population genetics and (4) an ecological succession model are briefly mentioned. Evolutionary dynamics are mathematically equivalent. to statistical thermodynamics.

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Endosome-Lysosome Interaction

Masato OHASHI

1991 Volume 31 Issue 6 Pages 33-37
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_33

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Brain Wave and Fractal Analysis

Yoshiya SHINAGAWA, Hiromi SENO

1991 Volume 31 Issue 6 Pages 38-42
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_38

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Physiological function of S-antigen

Takaharu SEKI

1991 Volume 31 Issue 6 Pages 43-45
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_43

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Immobilized operon as a kinetic tool for analyzing transcription.

Hiroyuki TERADA, Nobuo SHIMAMOTO

1991 Volume 31 Issue 6 Pages 49-52
Published: November 25, 1991
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2142/biophys.31.6_49

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