著者

Toshio TANAKA Tamiko WATANABE Yusuke EGUCHI Tadashi YOSHIMOTO

出版者

Japanese Society of Animal Science

雑誌

日本畜産学会報 (ISSN:1346907X)

巻号頁・発行日

vol.71, no.3, pp.300-304, 2000-05-25 (Released:2008-03-10)

参考文献数

15

被引用文献数

6 8

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In this study, an experiment was carried out to clarify the color perception in dogs. Two female Shiba breed dogs were trained using an operant conditioning method in which they pressed a switch with their muzzles in order to obtain some food, to discriminate between simultaneously presented colored and gray cards. The left and right positions of the two cards were shifted at random. After the dogs were fully trained, their color perception ability was tested on three primary colors, red, blue and green. The dogs were subjected daily to one or two sessions which consisted of 20 trials each.The criterion of successful discrimination was 3 consecutive sessions with more than 15 correct choices (P<0.05, Chi-square test). In the red vs. gray discrimination test, the dogs respectively took 3 and 12 sessions to reach the criterion. In the blue vs. gray and green vs. gray tests, both dogs were able to attain the criterion by the 13th session. The results of this study suggest that the color vision of dogs is relatively developed and dogs are able to discriminate between all three primary colors and gray.

著者

Tatsuya TSUJI Norimasa KANEDA Kunio KADO Teruo YOKOKURA Tadashi YOSHIMOTO Daisuke TSURU

出版者

The Pharmaceutical Society of Japan

雑誌

Journal of Pharmacobio-Dynamics (ISSN:0386846X)

巻号頁・発行日

vol.14, no.6, pp.341-349, 1991 (Released:2008-02-19)

参考文献数

25

被引用文献数

73 98

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A rat serum enzyme that catalyzes the conversion of a pro-drug, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11), to an anticancer drug, 7-ethyl-10-hydroxycamptothecin (SN-38), was purified and its properties were characterized. The enzyme was purified by column chromatography on diethylaminoethyl Toyopearl 650M, QAE-Sephadex, Sephadex G-150, Con A-Sepharose and high performance liquid chromatography with an ion-exchanger column. It was most active at pH 7.5 and was stable at pH 4-9 for 1 h at 30°C. The molecular weight was estimated to be 60 and 57 kDa by gel filtration and sodium dodecylsulfate-polyacrylamide gel electrophoresis methods, respectively, and the isoelectric point was 4.6, as determined by isoelectric focusing. The Km value for CPT-11 was 0.28 μM. This enzyme was inhibited by diisopropyl phosphorofluoridate (DFP) and phenylmethanesulfonyl fluoride (PMSF) but insensitive to eserine, p-chloromercuribenzoate (PCMB) and ethylenediaminetetraacetate (EDTA). The enzyme also hydrolyzed p-nitrophenylacetate (p-NPA), a commonly used substrate for esterases, but was not active toward acetylcholine, suggesting that the enzyme is a carboxylesterase [EC 3.1.1.1]. During the hydrolyses of CPT-11 and p-NPA, an initial burst phenomenon similar to that found in the α-chymotrypsincatalyzed hydrolysis of p-NPA was observed. Kinetic analysis revealed that the deacylation of the enzyme is the rate-limiting step in substrate hydrolysis. This enzyme was found to also split other ester derivatives of SN-38 besides CPT-11.