Structurally rigid, chiral spiro ammonium salts of type (R, R)- or (S, S)-1 derived from commercially available (R)- or (S)-1, 1′-bi-2-naphthol have been designed as new C2-symmetric chiral phase transfer catalysts and successfully applied to the highly efficient, catalytic enantioselective alkylation of tert-butyl glycinate Schiff base under mild phase transfer conditions to furnish α-alkyl-α-amino acids and α, α-dialkyl-α-amino acids with excellent enantioselectivity. These catalysts have been also utilized for the asymmetric terminal functionallization of peptides and asymmetric direct aldol reaction of glycine derivative.
(Communicated by Hitosi NOZAKI, M. J. A., Sept. 12, 2003)
Transitional cell carcinoma (TCC) in the urinary tract is characterized by the development of multiple tumors in time and space. When cystectomy is performed, urinary tract is reconstructed by various options including a neobladder using patient’s own intestine anastomosed to the urethra. This procedure assures normal voiding from the urethra even after cystectomy. Use of the urethra for preserving urethral voiding and function of a neobladder are reviewed from viewpoints of carcinogenesis and quality of life after cystectomy. Incidence of subsequent urethral cancer arising after cystectomy is relatively high, however, if high risk patients are appropriately excluded, a neobladder can be constructed safely from the oncologic standpoint and patient’s quality of life.
(Communicated by Takashi SUGIMURA, M. J. A., Sept. 12, 2003)
A specimen of ammonite obtained by Toshio Shimanuki from the lower Cenomanian (Cretaceous) outcrop in the Hobetsu district of Hokkaido, northern Japan, represents a new species of Lewesiceras (Pachydiscidae). In as much as Cenomanian specimens hitherto reported under Lewesiceras have been too immature for precise generic assignment, the present specimen is large enough to reach the adult stage. It represents a new species of Lewesiceras, and shows in some respects a step in the evolutionary change of characters from late Albian Eopachydiscus to the typical Turonian species of Lewesiceras.
(Contributed by Tatsuro MATSUMOTO, M. J. A., Sept. 12, 2003)
Based on the four specimens from the Lower Devonian (Emsian?) D4 Member of the Fukuji Formation, and a specimen from an unknown locality, a new genus and species of the oncocerid cephalopod, Devonohelicoceras hidaense, is described as the second known oncocerid from Japan. The present genus is most similar to the Late Silurian genus Foersteoceras, but differs in its weakly depressed whorl section, submarginal siphuncle with positional shifting, and well-developed actinosiphonate deposits. It is likely that the actinosiphonate deposits functioned as a substratum of adhesive liquid which has a lower specific gravity than the sea water.
(Communicated by Tatsuro MATSUMOTO, M. J. A., Sept. 12, 2003)
Capsaicin is a pungent principle of hot red pepper and a non-nutrient. Capsaicin supplementation to high fat diet prevents fat deposit in the adipose tissue through secretion of adrenaline from the adrenal gland via activation of adrenal sympathetic nerve in rats. The chemical structure of a capsaicin analog found in non-pungent red pepper which was selected and fixed from a pungent variety was recently determined by our group to be a novel compound, capsiate. The gastrointestinal absorption and the metabolism of capsiate after oral administration in rats was studied. Capsiate rapidly disappeared from upper region of the gastrointestinal tract. It was cleaved to vanillyl alcohol and vanillic acid. The cleaved products were excreted in the urine as a conjugated complex such as glucuronide. The effect of capsiate on adrenaline secretion from the adrenal medulla of anesthetized rats was investigated. Capsiate evoked rapid and transient adrenaline secretion as dose-dependent manner. Capsazepine, a specific inhibitor of vanilloid (capsaicin) receptor subtype 1 (VR1), blocked capsiate-induced adrenaline secretion to show the participation of VR1 for this response. These results support that non-nutrients such as capsaicin and capsiate are well absorbed into blood and play important roles in regulating energy and lipid metabolism.
(Communicated by Tadashi INAGAMI, M. J. A., Sept. 12, 2003)
In the light of crystal 3D structures of feast/famine regulatory proteins (FFRPs), biochemical and biological experiments characterizing DNA-binding by FFRPs, carried out by other groups, have been reanalyzed. An important conclusion is that the consensus sequences of DNA sites recognized by dimers of types of FFRPs are in the same form of NANBNCNDNETTTNENDNCNBNA, where, e.g., NA is the base complementary to NA (e.g., when G is NA, C is NA), and NE is either A or T. The NANBNCND and NDNCNBNA parts are different among FFRPs, and are important for discrimination between DNA promoters. The cluster of four T bases (i.e. the three Ts plus NE or NE) in the center appears to be important for bending of the DNA sites, and possibly used as the unit for formation of superstructures. Either 7-8 or ∼18 (i.e. 7-8 plus a helical turn of DNA, ∼10.5) basepairs are inserted between dimer-binding sites in many promoters, e.g. [NANBNCNDNETTTNENDNCNBNA]N1N2N3N4N5N6N7[NANBNCNDNETTTNENDNCNBNA], when dimer-binding sites repeat, most frequently, four times.
(Communicated by Masanori OTSUKA, M. J. A., Sept. 12, 2003)
It is generally assumed that neural stem cells give rise first to neuronal precursor cells, and that these precursor cells then proliferate extensively before terminally differentiating into postmitotic neurons. It is still not clear, however, whether the precursor cells are irreversibly determined to differentiate into neurons. In this study, we isolated immature cerebellar granule cell precursors from the developing mouse cerebellum. The immature precursors differentiated into granule cells in the absence of any signaling molecule, indicating that differentiation into neurons is the default pathway for these cells. A part of these immature neuronal precursors, however, differentiated into astrocytes when exposed to sonic hedgehog and bone morphogenetic proteins. Our results suggest that some, at least, neuronal precursor cells are not irreversibly committed to differentiating into neurons, but still have the plasticity to differentiate into astrocytes.
(Communicated by Tamio YAMAKAWA, M. J. A., Sept. 12, 2003)