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141.
Tetsuo Sawai Akihito Yamaguchi Akiko Saiki Kazuki Hoshino 《FEMS microbiology letters》1992,95(1):105-108
The diffusion rates of nalidixic acid, ofloxacin and ofloxacin's two optically active isomers through OmpF channels were measured in proteoliposomes and compared with the rates of beta-lactams. The four quinolones showed high diffusion rates, exceeding that of cephaloridine and being comparable to imipenem. There was no significant difference in diffusion rate between nalidixic acid and ofloxacin, or between the two optically active isomers. The diffusion rates of enoxacin and norfloxacin were also estimated to be higher than many beta-lactams. 相似文献
142.
143.
Hiroki Yanagida Takefumi Morita Juhyon Kim Keitaro Yoshida Kazuki Nakajima Yutaka Oomura Matthew J. Wayner Kazuo Sasaki 《Peptides》2008,29(6):912-918
Ghrelin is an endogenous ligand for the growth hormone (GH) secretagogue (GHS) receptor (GHS-R) and a potent stimulant for GH secretion even in infantile rats before puberty. Although the ventromedial nucleus of the hypothalamus (VMH) might be a site of action for ghrelin to induce GH release, the electrophysiological effect of ghrelin on VMH neurons in infantile rats remains to be elucidated. Thus, the purpose of the present study was to investigate the effect of ghrelin on VMH neurons using hypothalamic slices of infantile rats. Ghrelin excited a majority of VMH neurons in a concentration-dependent manner. VMH neurons that were excited by GH releasing peptide-6 (GHRP-6), a synthetic GHS, were also excited by ghrelin and vice versa. Repeated application of ghrelin to the same VMH neuron decreased progressively the excitatory responses depending on the number of times it was administered. The excitatory effect of ghrelin on VMH neurons in normal artificial cerebrospinal fluid (ACSF) persisted in low Ca2+-high Mg2+ ACSF. The present results indicate that (1) ghrelin excites a majority of VMH neurons dose-dependently and postsynaptically and (2) the excitatory effects of ghrelin are mimicked by GHRP-6 and desensitized by repeated applications of ghrelin. 相似文献
144.
145.
Ability of the endangered species Papaver fauriei to produce hybrids with a cultivated poppy (Papaver sp.) 下载免费PDF全文
Papaver fauriei is an endemic and endangered species that grows only on the gravelly alpine slopes of Mt. Rishiri, Japan. Cultivated poppy (Papaver sp.), the species name of which is unknown, has been introduced to the natural habitats of P. fauriei through human activities. Because the appearance and internal transcribed spacer (ITS) sequences of these two poppies are highly similar, it is of concern that they could produce hybrids in their natural habitats. Thus, first, the ability of these two poppies to produce hybrids was analyzed by artificial fertilization in this study. A large number of seeds were produced by reciprocal crosses between P. fauriei and the cultivated poppy, comparable with the number of seeds obtained by self‐ or cross‐fertilization of P. fauriei or the cultivated poppy. In addition, high germination was observed for seeds obtained from crosses between the two poppies, and deleterious phenotypes, such as albinism and dwarfism, were not detected in the F1 generation. These results indicate that after pollination, there is no reproductive isolation between the two poppies. Second, we sequenced the internal transcribed spacer (ITS) region of 240 poppy individuals collected from the gravelly alpine slopes of Mt. Rishiri, and 66 showed the sequence of P. fauriei, whereas 174 showed the sequence of the cultivated poppy. However, the ITS sequence that confirms hybridism between the two poppies was not detected in these individuals, indicating that hybridization of P. fauriei and the cultivated poppy rarely occurs under natural conditions. Unknown mechanism(s) appear to prevent cross‐pollination between the two poppies. 相似文献
146.
This study examined a host-parasite relationship between chestnut goby Gymnogobius castaneus (O’Shaughnessy 1875) and a unionid mussel Anemina arcaeformis (Heude 1877) in three floodplain water bodies of the Ishikari River. Field observations of gravidity between summer (July 2016) and spring (May 2017) revealed that female A. arcaeformis began incubating eggs in September, and all reached a fully ripe-glochidia-gravid stage by May with a decreasing trend in the proportion of gravid individuals. Two laboratory experiments, in which field-caught G. castaneus were artificially infected by glochidia of A. arcaeformis, showed that transformation rates were among the highest ever reported for A. arcaeformis (an average across all the surviving individuals: 47.9%) with a shorter development time in warmer environments. Transformation rates did not differ among sympatric or allopatric pairs, nor decrease when infected twice. Relatively high transformation rates were attributed to high glochidia attachments to gills and mouth cavity (approximately 30% of initially attached individuals) following the highest to fins, or a reduced immunity against infection due to colder environments. Overall, our study demonstrated that chestnut goby (G. castaneus) served as a suitable host of winter-breeding A. arcaeformis. Together with records of the expanded distribution of these two species in the past 30 years, it might be relatively recently that these two have colonized the study areas after extensive land changes, with A. arcaeformis having benefited from a successful host-parasite relationship. 相似文献
147.
Colonies of Probolomyrmex longinodus collected in Yonaguni Island, the Ryukyus, Japan contained several dealate queens, only one of which was inseminated and reproduced. All queens and workers had only one ovariole per ovary. 相似文献
148.
149.
Synergistic antitumor effects of interleukin-12 gene transfer and systemic administration of interleukin-18 in a mouse bladder cancer model 总被引:2,自引:0,他引:2
Kazuki Yamanaka Isao Hara Hiroshi Nagai Hideaki Miyake Kazuo Gohji Mark J. Micallef Masashi Kurimoto Soichi Arakawa Sadao Kamidono 《Cancer immunology, immunotherapy : CII》1999,48(6):297-302
We introduced the interleukin-12 (IL-12) gene into the mouse bladder cancer cell line (MBT2) to establish sublines that secrete
bioactive IL-12. IL-12-secreting MBT2 (MBT2/IL-12) sublines were completely rejected when subcutaneously implanted into immunocompetent
syngeneic C3H mice. Although this antitumor effect did not change when IL-12-secreting cells were injected into immunodeficient
mice whose CD8+ T or CD4+ T cells had been depleted by the corresponding antibody, it was abrogated when natural killer cells were depleted by anti-asialoGM1
antibody. In addition, when parental MBT2 cells mixed with MBT2/IL-12 cells were subcutaneously injected into mice, admixed
MBT2/IL-12 inhibited the growth of the parental tumor. Furthermore, this antitumor effect was enhanced by systemic IL-18 administration.
This synergism was abrogated when the mice were treated with interferon-γ-neutralizing antibody in vivo. In conclusion, local
secretion of IL-12 led to effective antitumor activity that was enhanced by systemic administration of IL-18. Interferon-γ
plays an important role in the synergism of IL-12 gene transduction and systemic administration of IL-18.
Received: 7 May 1998 / Accepted: 27 May 1999 相似文献
150.
Hideaki Yuasa Rei Kajitani Yuta Nakamura Kazuki Takahashi Miki Okuno Fumiya Kobayashi Takahiro Shinoda Atsushi Toyoda Yutaka Suzuki Nalinee Thongtham Zac Forsman Omri Bronstein Davide Seveso Enrico Montalbetti Coralie Taquet Gal Eyal Nina Yasuda Takehiko Itoh 《DNA research》2021,28(4)
The crown-of-thorns starfish (COTS) is a coral predator that is widely distributed in Indo-Pacific Oceans. A previous phylogenetic study using partial mitochondrial sequences suggested that COTS had diverged into four distinct species, but a nuclear genome-based analysis to confirm this was not conducted. To address this, COTS species nuclear genome sequences were analysed here, sequencing Northern Indian Ocean (NIO) and Red Sea (RS) species genomes for the first time, followed by a comparative analysis with the Pacific Ocean (PO) species. Phylogenetic analysis and ADMIXTURE analysis revealed clear divergences between the three COTS species. Furthermore, within the PO species, the phylogenetic position of the Hawaiian sample was further away from the other Pacific-derived samples than expected based on the mitochondrial data, suggesting that it may be a PO subspecies. The pairwise sequentially Markovian coalescent model showed that the trajectories of the population size diverged by region during the Mid-Pleistocene transition when the sea-level was dramatically decreased, strongly suggesting that the three COTS species experienced allopatric speciation. Analysis of the orthologues indicated that there were remarkable genes with species-specific positive selection in the genomes of the PO and RS species, which suggested that there may be local adaptations in the COTS species. 相似文献