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Hiromi Koma Yasuhiro Yamamoto Tomonari Fujita Tatsurou Yagami 《Biochemistry and Biophysics Reports》2019
Renal cell carcinoma (RCC) is relatively resistant to chemotherapy and radiotherapy. Clear cell RCC (ccRCC) accounts for the majority of RCC, which have mutations or epigenetic silencing of the von Hippel–Lindau (VHL) gene. VHL-positive Caki-2 cells are killed by an endogenous anticancer substance, 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2). The MTT reduction assay reflecting mitochondrial succinate dehydrogenase activity was employed for assessment of cell viability. We confirmed anticancer activities of camptothecin (topoisomerase I inhibitor), etoposide (topoisomerase II inhibitor), doxorubicin (topoisomerase II inhibitor) in VHL-positive Caki-2 cells. Combination of topoisomerase inhibitors with 15d-PGJ2 exhibited the synergistic effect in VHL-positive Caki-2 cells. However, 15d-PGJ2 did not increase cytotoxicities of topoisomerase inhibitors on VHL-negative 786-O cells. In addition, the 15d-PGJ2-enhanced antitumor activity of topoisomerase inhibitors was detected in neither VHL-positive nor VHL-negative RCC4 cells. Our finding indicated that 15d-PGJ2 enhanced the antitumor activity of topoisomerase inhibitors independently of VHL. 相似文献
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Development of an all-in-one inducible lentiviral vector for gene specific analysis of reprogramming
T Yamaguchi S Hamanaka A Kamiya M Okabe M Kawarai Y Wakiyama A Umino T Hayama H Sato YS Lee M Kato-Itoh H Masaki T Kobayashi S Yamazaki H Nakauchi 《PloS one》2012,7(7):e41007
Fair comparison of reprogramming efficiencies and in vitro differentiation capabilities among induced pluripotent stem cell (iPSC) lines has been hampered by the cellular and genetic heterogeneity of de novo infected somatic cells. In order to address this problem, we constructed a single cassette all-in-one inducible lentiviral vector (Ai-LV) for the expression of three reprogramming factors (Oct3/4, Klf4 and Sox2). To obtain multiple types of somatic cells having the same genetic background, we generated reprogrammable chimeric mice using iPSCs derived from Ai-LV infected somatic cells. Then, hepatic cells, hematopoietic cells and fibroblasts were isolated at different developmental stages from the chimeric mice, and reprogrammed again to generate 2nd iPSCs. The results revealed that somatic cells, especially fetal hepatoblasts were reprogrammed 1200 times more efficiently than adult hepatocytes with maximum reprogramming efficiency reaching 12.5%. However, we found that forced expression of c-Myc compensated for the reduced reprogramming efficiency in aged somatic cells without affecting cell proliferation. All these findings suggest that the Ai-LV system enables us to generate a panel of iPSC clones derived from various tissues with the same genetic background, and thus provides an invaluable tool for iPSC research. 相似文献
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Remote acquisition of information on ecosystem dynamics is essential for conservation management, especially for the deep ocean. Soundscape offers unique opportunities to study the behavior of soniferous marine animals and their interactions with various noise-generating activities at a fine temporal resolution. However, the retrieval of soundscape information remains challenging owing to limitations in audio analysis techniques that are effective in the face of highly variable interfering sources. This study investigated the application of a seafloor acoustic observatory as a long-term platform for observing marine ecosystem dynamics through audio source separation. A source separation model based on the assumption of source-specific periodicity was used to factorize time-frequency representations of long-duration underwater recordings. With minimal supervision, the model learned to discriminate source-specific spectral features and prove to be effective in the separation of sounds made by cetaceans, soniferous fish, and abiotic sources from the deep-water soundscapes off northeastern Taiwan. Results revealed phenological differences among the sound sources and identified diurnal and seasonal interactions between cetaceans and soniferous fish. The application of clustering to source separation results generated a database featuring the diversity of soundscapes and revealed a compositional shift in clusters of cetacean vocalizations and fish choruses during diurnal and seasonal cycles. The source separation model enables the transformation of single-channel audio into multiple channels encoding the dynamics of biophony, geophony, and anthropophony, which are essential for characterizing the community of soniferous animals, quality of acoustic habitat, and their interactions. Our results demonstrated the application of source separation could facilitate acoustic diversity assessment, which is a crucial task in soundscape-based ecosystem monitoring. Future implementation of soundscape information retrieval in long-term marine observation networks will lead to the use of soundscapes as a new tool for conservation management in an increasingly noisy ocean. 相似文献
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Thermonasty-like responses were observed on some main stems of Phryma leptostachya (Phrymaceae) plants cultivated in the open. To confirm the thermonastic nature of these responses, the plants were moved into an artificially illuminated chamber and observed under controlled conditions. At low temperatures (about 12°C) and in the dark, slanted terrestrial young main stems of P. leptostachya became prostrate. At higher temperatures (about 25°C) and in the dark, the prostrate stems became slanted. Their movement was confirmed under controlled conditions and is therefore considered to be thermonastic in nature. 相似文献
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A microchannel reactor system was used in a biodesulfurization process in which the rate of biodesulfurization in the oil/water
phase of the microchannel reaction was more than nine-fold that in a batch (control) reaction. In addition, the microchannel
reaction system using a bacterial cell suspension degraded alkylated dibenzothiophene that was not degraded by the batch reaction
system. This work provides a foundation for the application of a microchannel reactor system consisting of biological catalysts
using an oil/water phase reaction. 相似文献