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81.
M G Belvisi C D Stretton M Miura G M Verleden S Tadjkarimi M H Yacoub P J Barnes 《Journal of applied physiology》1992,73(6):2505-2510
Inhibitory nonadrenergic noncholinergic (i-NANC) nerves are the only neural bronchodilator pathway in human airways. Possible candidates for the neurotransmitter include vasoactive intestinal peptide (VIP) and nitric oxide (NO) and purines such as ATP. We have investigated the potential role of these neurotransmitters. Phosphoramidon (10(-5) M) significantly potentiated relaxations to low doses of VIP with no effect on i-NANC responses. Relaxations induced by VIp were abolished with alpha-chymotrypsin (2 U/ml), but i-NANC responses were unaffected. Reactive blue 2 had no effect on i-NANC neural responses, indicating that endogenous ATP was not involved. The NO synthase inhibitor L-NG-nitroarginine methyl ester (L-NAME, 10(-4) M) produced a concentration-dependent inhibition of the i-NANC response, producing almost complete inhibition at every frequency studied (0.5-40 Hz), whereas L-NG-monomethyl arginine was effective only at low stimulation frequencies. The inhibitory effect of L-NAME was partially reversed by L- but not D-arginine, and D-NAME was without effect. These results suggest that in human tracheal segments the neural bronchodilator response is mediated by NO, and there is no functional evidence for implicating VIP in this response. 相似文献
82.
Crosses between genotypically distinct thalli of the monoecious species Porphyra yezoensis were carried out using immature thallus fragments from green- and red-type color mutants and also wild-type thalli. As the genes governing the mutants are monogenic, recessive to the wild-type, and belong to the same linkage group, the degree of self-fertilization could be estimated based on the pigmentation of the resultant diploid conchocelis. The degree of self-fertilization in the cross between the green-type and the wild-type was 48.5–55.0%, and in the cross between the red-type and the wild-type was 45.1–56.5%. In the cross between the green- and red-type mutants, the degree of self-fertilization was 46.0–54.5% when the green-type was the female parent, and was 44.8–55.6% when the red-type was the female parent. 相似文献
83.
Stocking silver carp, a phytoplankton feeder, and bighead carp, an omnivorous plankton feeder, into an eutrophic lake at high
densities caused a dramatic change in the lake ecosystem.Microcystis, which had been dominant in summer and a main food of the fishes decreased markedly, and green algae smaller than 10 μm then
became dominant. Consequently, chlorophyll-a per unit area decreased slightly, while the rate of production was higher than that in the previous years. As the total density
of the fishes increased (from 0.09 to 0.11 fish m−2), the growth of silver carp was retarded, while that of bighead carp increased.Microcystis, was unable to become dominant due to increased grazing pressure by the fishes, and small green algae became dominant. The
lake conditions thus became more favourable for zooplankters which selectively consumed small green algae, and accordingly,
the production of zooplankton rose. Bighead carp consumed more animal food, which they assimilate at a higher rate than plant
food, and grew better in spite of the fact that the fish density increased. The feeding rate of silver carp was greatly reduced
because the green algae were too small to ingest, and the fish therefore grew poorly. Results of a computer simulation of
a model consisting of five compartments, representing the blue-green algae, green algae, zooplankton, silver and bighead carp,
support the food-web change observed in the lake. 相似文献
84.
85.
T Iwaoka T Umeda S Naomi F Miura J Inoue M Sasaki S Hamasaki T Sato 《Endocrinologia japonica》1990,37(1):151-157
Adrenal venous sampling of blood was performed for nine patients with aldosterone-producing adenoma (APA). Measurement of adrenal venous aldosterone is useful for localization of APA but difficult, because catheterization of the right adrenal vein is not easy, and the blood is diluted by nonadrenal flow. To solve these problems, levels of aldosterone (A; ng/dl) and cortisol (C; micrograms/dl) were measured in samples from the left adrenal vein (LAV) and the inferior vena cava (IVC), and the LAV A/C and (LAV A/C)/(IVC A/C) ratios were calculated. These ratios were also obtained for 16 patients with essential hypertension. The adenoma could be localized in three of the nine cases by the measurement of aldosterone alone, but the use of a LAV A/C ratio greater than 5 x 10(-3) and a (LAV A/C)/(IVA A/C) ratio less than 1.0 as criteria separated the patients into those with a left APA, right APA, or essential hypertension. Consequently, adrenal venous sampling and the calculation of these ratios enables preoperative localization of APA with more accuracy, especially when the tumor is small or the result of CT and adrenal scintigraphy is not consistent. 相似文献
86.
Y Miura Y Inaba T Tsuda S Tokuhisa K Sato H Akashi 《National Institute of Animal Health quarterly》1982,22(4):154-158
Bovine sera collected in various parts of Japan were subjected to seroepizootiological tests with bluetongue virus type 1 (BTV1), type 12 (BTV12), and type 20 (BTV20). All these viruses have been widely disseminated among cattle in the southern part of Japan in 1974. Relatively high incidences of neutralizing (NT) antibody against the three viruses were shown among cattle in the Kyushu district, including Okinawa Prefecture, or the southern part of Japan, but extremely low or incidences in Hokkaido, or the northern part of Japan. The incidence of reactors was higher in old animals. Cattle in Okinawa Prefecture showed a high rate of seroconversion for all the viruses during the summer of 1979. None of the animals seroconverted, however, manifested any sign of disease. Seroepizootiological investigation made it clear that BTV1, BTV12 and BTV20 had existed in Japan and that the epizootic of bluetongue virus infection started during a period from summer through early autumn. 相似文献
87.
Entamoeba histolytica: localization and characterization of ca2+-dependent nucleotidases 总被引:2,自引:0,他引:2
T Takeuchi S Kobayashi M Masuda M Tanabe S Miura T Fujiwara 《International journal for parasitology》1981,11(3):209-215
An activity of Ca2+-dependent nucleotidase was detected in axenically-cultivated trophozoites of Entamoeba histolytica. The enzyme was concentrated by differential and sucrose density gradient centrifugation and catalyzed hydrolysis of nucleoside tri- and diphosphates and also thiamine pyrophosphate. Hydrolysis of nucleoside mono-phosphates was not affected by Ca2+. Among substrates tested, ATP was most active. Addition of Zn2+ or heat treatment almost abolished the enzyme activity. The enzyme exhibited almost the identical activity at acid and neutral pH. Among 6 bands isolated by polyacrylamide gel electrophoresis, 4 were stained with ATP, UTP, CTP and ADP, whereas the other 2 were stained only with ATP, UTP and CTP. The concentrated enzyme preparation, primarily composed of membrane fragments, also had activities of acid phosphatase, acid inorganic pyrophosphatase, 5'-nucleotidase and Mg2+-dependent ATPase. These observations suggest that E. histolytica has 2 Ca2+-dependent nucleotidases, i.e. one Ca2+-dependent ATPase and the other Ca2+-dependent nucleoside diphosphatase or an apyrase-like enzyme, and that these nucleotidases are at least partially associated with the plasma membrane or an organelle of lysosomal nature in this parasite. 相似文献
88.
Antisera to purified gamma-glutamyltranspeptidase (gamma GTP) from human and rat kidney were prepared, and their reactivities toward purified gamma GTP from kidney, liver, and bile were tested. The following results were obtained: 1. On double immunodiffusion, Triton-solubilized gamma GTP, and papain-solubilized gamma GTP from rat kidney gave single precipitin lines which fused completely against antiserum to the purified enzyme from rat kidney. 2. An antigen-antibody complex of human kidney gamma GTP retained about 50% of the catalytic activity of the antigen. 3. Double immunodiffusion showed that the enzymes from human liver, kidney, and bile were immunologically identical. 4. Antiserum to rat kidney gamma GTP partially cross reacted with human gamma GTP, but antiserum to human gamma GTP reacted only very weakly with rat gamma GTP. It is concluded that gamma GTP of human liver, kidney, and bile are immunologically identical and that rat gamma GTP and human gamma GTP have certain antigenic determinants in common. 相似文献
89.
The resonance Raman (RR) spectra of the complexes of D-amino acid oxidase (DAO) with benzoate derivatives were measured. The RR spectra of complexes of DAO with benzoate derivatives excited at 514.5 nm are similar to one another and also similar to that of oxidized flavin. In the cases of DAO-o-NH2-benzoate and DAO-o-OH-benzoate complexes, however, the line at 568 or 565 cm-1, derived from the benzoate derivative, was intensified. In the case of DAO-o-NH2-benzoate complex, which has an intense charge-transfer absorption band, the resonance enhancement of the Raman lines at 1583 and 568 cm-1 in the RR spectrum excited at 632.8 nm is striking. The former line is known to involve the vibrational displacements of the N(5) and C(4a) atoms of isoalloxazine and the latter is considered to be derived from a ring deformation mode of o-NH2-benzoate. This suggests that the o-NH2-benzoate molecule lies along the N(5)-C(4a) bond and parallel to the flavin face. A Raman line derived from o-OH-benzoate in the RR spectrum of DAO-o-OH-benzoate complex excited at 514.5 nm was detected. This result supports the view that the complex has a charge-transfer band, as has been pointed out by Massey and Ganther. Also, the spectrum of quasi-DAO-o-OH-benzoate complex is identical with that of the complex of DAO, suggesting that the active sites of these two enzymes have similar structures. 相似文献
90.
Absence of pantothenic acid in gramicidin S synthetase 2 obtained from some mutants of Bacillus brevis 总被引:2,自引:0,他引:2
The pantothenic acid content of gramicidin S synthetase 2(GS 2) was estimated microbiologically with enzymes obtained from the wild strain and gramicidin S-lacking mutant strains of Bacillus brevis. Four mutant enzymes from BI-4, C-3, E-1, and E-2 lacked pantothenic acid. Other mutant enzymes from BII-3, BI-3, BI-9, and BI-2 contained the same amount of pantothenic acid as the wild-type enzyme. Pantothenic acid-lacking GS 2 belonged to group V of mutant enzymes, which could activate all amino acids related to gramicidin S; their complementary enzyme, gramicidin S synthetase 1(GS 1), lacked racemizing activity. To ascertain whether 4'-phosphopantetheine is involved in the formation of D-phenylalanyl-L-prolyl diketopiperazine (DKP) and gramicidin S, combinations were tested of intact GS 1 from the wild strain with various mutant GS 2 either containing or lacking pantothenic acid. Only the combinations of wild-type GS 1 with mutant GS 2 containing pantothenic acid could synthesize DKP. Combinations with pantothenic acid-lacking GS 2 also failed to elongate peptide chains. Pantothenic acid-lacking GS 2 could bind the four amino acids which constitute gramicidin S as acyladenylates and thioesters, but the binding abilities were lower than those of the wild-type enzyme and other mutant enzymes containing the pantothenic group. 相似文献