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Volume 82, Issue 7
Displaying 1-6 of 6 articles from this issue
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Reviews
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Koji OKABAYASHI, Makoto ASASHIMA2006 Volume 82 Issue 7 Pages 197-207
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESSMesoderm induction as a result of the interaction between endoderm and ectoderm is one of the most crucial events in vertebrate development. We identified activin as a strong mesoderm-inducing factor in an animal cap assay, an in vitro assay system using amphibian pluripotential cell mass. Activin induces mesodermal tisswes including most dorsal mesodermal tissue, notochord (which has important roles in neural induction, somite segmentation, and endodermal organogenesis), and its effects are concentration-dependent. Animal cap cells treated with high concentrations of activin differentiate into anterior endoderm, which can act as an organizer, or center of body patterning. We have established an in vitro induction system for 22 different organs and tissues using animal cap cells, and have isolated many organ-specific genes. With these useful methods, and analysis of newly isolated tissue- and organ-specific genes, the molecular biological “road map” for organogenesis is being established.
(Communicated by Masatoshi TAKEICHI, M.J.A.)View full abstractDownload PDF (792K) -
Hiroyuki TSUDA, Katsumi FUKAMACHI, Jiegou XU, Kazunori SEKINE, Shigeto ...2006 Volume 82 Issue 7 Pages 208-215
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESSIncreasing attention is being paid to chemopreventive agents for individuals at high risk of cancer. We have concentrated on bovine lactoferrin (bLF), an 80kDa iron-binding glycoprotein known to have anti-microbial and immunoprotective effects. Lactoferrin is particularly abundant in colostrum, and is also present in tears, saliva and seminal and uterine secretions. However, only little is known regarding its influence on carcinogenesis. We have shown preventive effects of bLF and its fragment peptide, lactoferricin (bLFcin), consisting of a 25 amino acid sequence without iron binding capacity, on chemically-induced colon carcinogenesis in the rat and transplanted carcinoma cell metastasis in the mouse. The mechanisms are wide-spectrum, including elevation of caspase-1 and IL-18 in the small intestine, enhancement of the cell killing activity of cytotoxic T and natural killer (NK) cells, and anti-inflammatory and anti-angiogenic effects. It also inhibits the induction of liver CYP1A2, a carcinogen activating enzyme, and induces apoptosis in the colon epithelium of carcinogen treated rats. Thus, bLF possesses multi-functional potential to suppress carcinogenesis and is a good candidate for practical application in humans.
(Communicated by Takashi SUGIMURA, M.J.A.)View full abstractDownload PDF (638K)
Original Papers
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Yasuhiro IBA, Shin-ichi SANO2006 Volume 82 Issue 7 Pages 216-223
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESSIn this paper, we describe an Aptian (Early Cretaceous) larger foraminiferal species Orbitolina (Mesorbitolina) parva from the limestone olistoliths in the lower part of the Yezo Group in the Yubari-Ashibetsu area, central Hokkaido and from limestone pebbles in the lowermost part of the Yezo Group in the Nakagawa area, northern Hokkaido. This is the first report of this species from the circum-North Pacific regions. Based on its occurrences, the shallow-marine carbonates, re-deposited in the lower part of the Yezo Group, are precisely assigned in age to the Late Aptian. Comparison of the lower part of the Yezo Group in central and northern Hokkaido indicates differences of the Aptian-Albian depositional history between the two areas. This study reveals that after Late Aptian, Mesogean key taxa (typical Cretaceous Tethyan biota) demised in the Northwest Pacific.
(Communicated by Tatsuro MATSUMOTO, M.J.A.)View full abstractDownload PDF (483K) -
Khalid Masood2006 Volume 82 Issue 7 Pages 224-231
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESSWe investigate the inverse problem associated with the heat equation involving recovery of initial temperature distribution in a two-layer cylinder with perfect thermal contact at the interface. The heat equation is solved backward in time to obtain a relationship between the final temperature distribution and the initial temperature profile. An integral representation for the problem is found, from which a formula for initial temperature is derived using Picard's criterion and the singular system of the associated operators. The known final temperature profile can be used to recover the initial temperature distribution from the formula derived in this paper. A robust method to regularize the outcome by introducing a small parameter in the governing equation is also presented. It is demonstrated with the help of a numerical example that the hyperbolic model gives better results as compared to the parabolic heat conduction model.
(Edited by Takeo YOKOBORI, M.J.A.)View full abstractDownload PDF (185K) -
Zhi-Hui SU, Munehiro OKAMOTO, Osamu TOMINAGA, Katsumi AKITA, Noboru KA ...2006 Volume 82 Issue 7 Pages 232-250
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESS
Supplementary materialAn approach to deduce the mechanism of stabilization of the hybrid-derived populations in the Ohomopterus ground beetles has been made by comparative studies on the phylogenetic trees of the mitochondrial and nuclear DNA. A phylogenetic tree based on the internal transcribed spacer (ITS) of nuclear ribosomal gene roughly reflects the relations of morphological species group, while mitochondrial NADH dehydrogenase subunit 5 (ND5) gene shows a considerable different topology on the tree; there exist several geographically-linked lineages, most of which consist of more than one species. These results suggest that the replacement of mitochondria has occurred widely in the Ohomopterus species. In most cases, hybridization is unidirectional, i.e., the species A ( ?? ) hybridized with another species B ( ?? ) and not vice versa, with accompanied replacement of mitochondria of A by those of B. The results also suggest that partial or complete occupation of the distribution territory by a hybrid-derived morphological species. The morphological appearance of the resultant hybrid-derivatives are recognized as that of the original species A. Emergence of a morphological new species from a hybrid-derived population has been exemplified.
(Communicated by Takashi SUGIMURA, M.J.A.)View full abstractDownload PDF (1277K) -
Yosuke Aoki2006 Volume 82 Issue 7 Pages 251-256
Published: 2006
Released on J-STAGE: November 18, 2006
JOURNAL FREE ACCESSAddition of azurocidin, a protein in granulocytes similar to serine proteases but has no protease activity because of replacement of the active serine residue by glycine, to the incubation mixture containing medullasin induced elastinolytic activity of medullasin. Both medullasin and human leukocyte elastase were already shown to have negligible elastinolytic activity (Aoki, Y. et al. J. Biochem. 114, 122, 1993). Elastinolytic activity of medullasin was induced dose-dependently by the addition of azurocidin. Medullasin activity determined by using apo-ornithine transaminase or casein as substrates or that by N-methoxy-succinyl-(Ala)2-Pro-Val-p-nitroanilide as substrate remained unchanged when azurocidin was added to the tube containing medullasin. Therefore, azurocidin is considered to cause an appearance of elastinolytic activity of medullasin without affecting the protease activity of it.
(Edited by Masanori OTSUKA, M.J.A.)View full abstractDownload PDF (124K)
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