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N. Fujii N. Tomaru K. Okuyama T. Koike T. Mikami K. Ueda 《Plant Systematics and Evolution》2002,232(1-2):21-33
CpDNA variation in Japanese beech, Fagus crenata (Fagaceae), was studied in 45 populations distributed throughout the species' range. Two cpDNA regions were sequenced: the
non-coding region between the trnL (UAA) 5′exon and trnF (GAA), and the trnK region (including matK). Thirteen distinct cpDNA haplotypes were recognized and each haplotype was found to be geographically structured. Two major
clades (I and II+III) were revealed in phylogenetic analyses among the haplotypes using F. sylvatica as an outgroup. The haplotypes of Clade I were distributed mainly along the Japan Sea side of the Japanese Archipelago, while
those of Clade II+III occurred chiefly along the Pacific Ocean side. Consequently, the distribution of the two major cpDNA
clades suggests that there were two migration routes in the history of F. crenata; one along the Japan Sea and the other along the Pacific Ocean side of the Japanese Islands.
Received March 19, 2001 Accepted November 22, 2001 相似文献
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400 MHz two-dimensional nuclear Overhauser spectroscopy on anesthetic interaction with lipid bilayer 总被引:1,自引:0,他引:1
Interaction between a volatile anesthetic, methoxyflurane, and dipalmitoylphosphatidylcholine (DPPC) vesicle membrane was analyzed by nuclear Overhauser effect (NOE) difference spectroscopy and two-dimensional nuclear Overhauser spectroscopy (NOESY). The NOE difference spectra were obtained by selectively irradiating methoxy protons (hydrophobic end) of the anesthetic: a negative nuclear Overhauser effect of -2.94% was observed with the choline methyl protons of DPPC. The NOESY spectra revealed a cross-peak between the anesthetic methoxy protons and the choline methyl protons. A dipole-dipole interaction exists between the hydrophobic end of the anesthetic and the hydrophilic head group of DPPC. No other cross-peaks were observed. The anesthetic orients itself at the membrane/water interface by interacting with the hydrophilic surface of the DPPC membrane, leaving the hydrophilic end of the anesthetic molecule in the aqueous phase. The preferred residence site of dipolar volatile anesthetics is the membrane/water interface. 相似文献
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Cationic local anesthetics decreased the transition temperature of the anionic phospholipid (dimyristoylphosphatidic acid, DMPA) vesicles. The counterion concentration changes the electrical double layer effect, and affects the magnitude of temperature depression caused by anesthetics. From the counterion effect on the transition-temperature depression, the partition coefficients of cationic local anesthetics to liquid-crystalline and solid-gel DMPA membranes were separately estimated. The differences in the partition coefficients between solid-gel and liquid-crystalline membranes correlated to the nerve blocking potencies. There are at least two states in the nerve membranes: resting state at higher temperature and excited state at lower temperature. We speculate that the resting state corresponds to the liquid-crystalline state, and the excited state to the solid-gel state. The difference in the partition coefficients to the resting and excited states is the cause of local anesthesia. 相似文献
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The synthesis and biological properties are described of [Asu7,23']-beta-ANP-(7-28) (Asu, L-alpha-aminosuberic acid), a dicarba analog of beta-atrial natriuretic peptide (beta-ANP, an antiparallel dimer of human alpha-ANP with the chains linked by 7-23' and 7'-23 disulfide bonds). This Asu-analog (referred to as analog III) displaced 125I-alpha-ANP specifically bound to cultured rat vascular smooth muscle cells (VSMC) with an apparent Ki of 2.1 x 10(-8) M, but did not stimulate formation of intracellular cGMP at 10(-8) -10(-5) M. Analog III inhibited the alpha-ANP-stimulated cGMP production in VSMC competitively with a pA2 value of 7.45 and behaved as an antagonist of alpha-ANP in rat aorta smooth muscle relaxation. In addition, beta-ANP was also shown to inhibit the alpha-ANP-induced cGMP production in a dose-dependent manner. The mechanism of action of beta-ANP is also discussed. 相似文献
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T cell subsets responsible for clearance of Sendai virus from mouse lungs determined by adoptive transfer of immune spleen cell fractions to infected nude mice. T cells with antiviral activity developed in spleens by 7 days after intranasal infection. Spleen cell fractions depleted of Lyt-2+, Lyt-1+, or L3T4+ cells showed antiviral activity in vivo, although the degree of the activity was lower than that of control whole spleen cells. The antiviral activity of the Lyt-2+ cell-depleted fraction was consistently higher than that of L3T4+ (Lyt-1+)-depleted cells. In vitro cytotoxic activity against Sendai virus-associated, syngeneic lipopolysaccharide-blast cells was detected in stimulated cells from intraperitoneally immunized mice but was lost after depletion of Lyt-2+ cells. Multiple injection of anti-Sendai virus antibody into infected nude mice had no effect on lung virus titer. These results indicate that L3T4+ (Lyt-1+) and Lyt-2+ subsets are cooperatively responsible for efficient clearance of Sendai virus from the mouse lung. 相似文献
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Guineapig antibodies to Streptococcus pneumoniae (SPN) serotype 19F were detected by an enzyme-linked immunosorbent assay using a simple procedure. In experimentally infected hosts, antibody was detectable as early as 2 to 3 weeks after infection, and high titres were maintained for a long period. Antibodies higher than 1:64 were regarded as specific. In a field study, high antibody titres were shown in SPN enzootic colonies in contrast to negative or low antibody titres in a majority of the animals from non-enzootic and SPF colonies. 相似文献