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181.
Jie Zhang Tatsunori Sasaki Wei Li Kazuya Nagata Koji Higai Feng Feng Jian Wang Maosheng Cheng Kazuo Koike 《Bioorganic & medicinal chemistry letters》2018,28(7):1194-1197
Considerable attention has been paid to protein tyrosine phosphatase 1B (PTP1B) inhibitors as a potential therapy for diabetes, obesity, and cancer. Ten caffeoylquinic acid derivatives (1–10) from leaves of Artemisia princeps Pamp. (Asteraceae) were identified as natural PTP1B inhibitors. Among them, chlorogenic acid (3) showed the most potent inhibitory activity (IC50 11.1?μM). Compound 3 was demonstrated to be a noncompetitive inhibitor by a kinetic analysis. Molecular docking simulation suggested that compound 3 bound to the allosteric site of PTP1B. Furthermore, compound 3 showed remarkable selectivity against four homologous PTPs. According to these findings, compound 3 might be potentially valuable for further drug development. 相似文献
182.
Sayo Tomatsu Keita Ogiso Kazuya Fukuda Mayumi Deki Shin-Ichi Dewa Hisaya Manabe Makoto Sakurai Akihiko Shinomiya Tomoki Sunobe 《Ichthyological Research》2018,65(4):502-506
The gobiid fish, Trimma caudomaculatum, lives in groups. We investigated group structure, mating system and bidirectional sex change of this species. Four groups examined contained more than two males. The males were significantly larger than the females. By the observations in aquarium, the males occupied a nest and the females visited the nest for spawning. While there was no specific pair bond, the males mated with multiple females. Hence, this species establishes multi-male groups. In the experiments, four larger females had changed sex to male among 25 females. The smallest male changed to female in the group of four males. 相似文献
183.
Tetsuya Sakamaki Heungjin Ryu Kazuya Toda Nahoko Tokuyama Takeshi Furuichi 《International journal of primatology》2018,39(4):685-704
Intergroup interactions in primates vary from nonagonistic to severely aggressive. Food resources and fertile females cause intergroup aggression when groups defend resources and mates from other groups. Peaceful intermingling during intergroup encounters is rare but has been reported in several primates, including bonobos (Pan paniscus). Although intergroup encounters in bonobos occur at both nonprovisioned and provisioned sites, provisioning may be one factor responsible for frequent intergroup encounters. We studied intergroup encounters between one bonobo group (PE) and its neighboring groups, one semihabituated and two habituated groups, under nonprovisioned conditions in 2010–2015 at Wamba, Democratic Republic of Congo. We examined whether fruit abundance and females with sexual swellings influenced encounter frequency. PE group encountered the other groups on 7.1 days (mean, range: 0–19) per month. Up to four different groups met simultaneously at one location. Encounter frequency was highest around the yearly peak in fruit abundance, suggesting that reduced food competition is linked to increased encounter frequency. During periods of relatively low fruit abundance, the probability of an encounter was higher when a higher number of adult females with maximum sexual swellings were present, suggesting that the attractiveness of females with sexual swellings promoted group encounters during periods of relatively low fruit abundance. These findings suggest that both competition for food and the availability of females with sexual swellings influence encounter frequency in bonobos. 相似文献
184.
Yoshiko Iida Keiko Sawabe Masayo Kojima Kazuya Oguro Nobuo Nakanishi Hiroyuki Hasegawa 《European journal of biochemistry》2002,269(19):4780-4788
We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127, 121-127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca2+/calmodulin-dependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation. 相似文献
185.
M. Nakai Kiyotaka Toshimori Kazuya Yoshinaga Tetsuo Nasu Rex A. Hess 《Cell and tissue research》1998,294(1):145-152
Effects of a single, high dose of orally administered carbendazim (100 mg/kg) on acrosome formation in the early phases of
spermiogenesis were examined by electron microscopy and immunocytochemistry up to day 7.5 post-treatment. No obvious abnormality
of acrosome development was noted in the Golgi phase spermatids on day 1.5 post-treatment. On day 3, step 1 spermatids were
seen in stage III seminiferous tubules. In stage V tubules at this post-treatment interval, direct connections between the
trans-side saccules of the Golgi stacks and the outer acrosomic membranes were observed in step 5 spermatids. Similar direct
connections between these two organelles were also observed in the advanced round spermatids in later stages at days 4.5 and
7.5. On day 4.5, step 1 and 3 spermatids were seen in stage V tubules. On day 7.5, round spermatids with various abnormalities
of acrosome development were observed in stage VII tubules, in addition to the discontinuous and granular acrosomes reported
previously. These features were not observed in testes of control animals. In the immunocytochemical analysis using an antibody
mMN7 that recognizes a protein delivered from the Golgi apparatus to the acrosome, spermatids exposed to carbendazim showed
various abnormal immunostaining patterns in the acrosomes. On the other hand, strong immunoreactivity was observed in the
Golgi saccules connecting to the acrosomes. These results suggest that in testis treated with carbendazim acrosome development
is impaired during the early phases of spermiogenesis, and material supply from the Golgi apparatus to the acrosome is perturbed,
which is a possible cause of the abnormal development.
Received: 31 March 1998 / Accepted: 28 May 1998 相似文献
186.
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188.
The effect of photosynthetically active radiation and temperature on the photosynthesis of two Vietnamese species of Sargassum,S. mcclurei and S. oligocystum,based on the field and laboratory measurements
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Ryuta Terada Triet D. Vo Gregory N. Nishihara Kazuya Matsumoto Shogo Kokubu Yuki Watanabe Shigeo Kawaguchi 《Phycological Research》2016,64(4):230-240
SUMMARY The effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of two Vietnamese brown algae, Sargassum mcclurei and S. oligocystum (Fucales), were determined by field and laboratory measurements. Dissolved oxygen sensors and pulse‐amplitude modulated (PAM) fluorometry were used for the measurements of photosynthetic efficiency. A Diving‐PAM revealed that underwater measurements of the effective quantum yield (Φ PSII ) of both species declined with increasing incident PAR, with minimum Φ PSII occurring during noon to early afternoon. Φ PSII recovered in the evening, indicating photo‐adaptation to excessive PAR. In laboratory experiments, Φ PSII also decreased under continuous exposure to 1000 μmol photons m?2 s?1; and full recovery occurred after 12 h of dark acclimatization. The net photosynthesis – PAR experiments of S. mcclurei and S. oligocystum conducted at 28°C revealed that the net photosynthetic rate quickly increased at PAR below the saturation irradiance of 361 and 301 μmol photons m?2 s?1 and nearly saturated to maximum net photosynthetic rates of 385 and 292 μg O2 gww ? 1 min?1 without photoinhibition, respectively. Gross photosynthesis and dark respiration experiments determined over a range of temperatures (12–40°C), revealed that the maximum gross photosynthetic rates of 201 and 147 μg O2 gww ? 1 min?1 occurred at 32.9 and 30.7°C for S. mcclurei and S. oligocystum, respectively. The dark respiration rates increased exponentially over the temperature ranges examined. The estimated maximum value of the maximum quantum yield occurred at 19.3 and 20.0°C and was 0.76 and 0.74, respectively. Similar to the natural habitat of the study site, these two species tolerated the relatively high temperatures and broad range of PAR. The ability of these species to recover from exposure to high PAR is one of the mechanisms that allow them to flourish in the shallow water environment. 相似文献
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