全文获取类型
收费全文 | 282篇 |
免费 | 15篇 |
专业分类
297篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 14篇 |
2012年 | 12篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 20篇 |
2008年 | 16篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
111.
Yamamoto Y Mochida S Miyazaki N Kawai K Fujikura K Kurooka T Iwasaki K Sakisaka T 《The Journal of biological chemistry》2010,285(52):40943-40955
Neurotransmitter release is triggered by Ca(2+) binding to a low affinity Ca(2+) sensor, mostly synaptotagmin-1, which catalyzes SNARE-mediated synaptic vesicle fusion. Tomosyn negatively regulates Ca(2+)-dependent neurotransmitter release by sequestering target SNAREs through the C-terminal VAMP-like domain. In addition to the C terminus, the N-terminal WD40 repeats of tomosyn also have potent inhibitory activity toward Ca(2+)-dependent neurotransmitter release, although the molecular mechanism underlying this effect remains elusive. Here, we show that through its N-terminal WD40 repeats tomosyn directly binds to synaptotagmin-1 in a Ca(2+)-dependent manner. The N-terminal WD40 repeats impaired the activities of synaptotagmin-1 to promote SNARE complex-mediated membrane fusion and to bend the lipid bilayers. Decreased acetylcholine release from N-terminal WD40 repeat-microinjected superior cervical ganglion neurons was relieved by microinjection of the cytoplasmic domain of synaptotagmin-1. These results indicate that, upon direct binding, the N-terminal WD40 repeats negatively regulate the synaptotagmin-1-mediated step of Ca(2+)-dependent neurotransmitter release. Furthermore, we show that synaptotagmin-1 binding enhances the target SNARE-sequestering activity of tomosyn. These results suggest that the interplay between tomosyn and synaptotagmin-1 underlies inhibitory control of Ca(2+)-dependent neurotransmitter release. 相似文献
112.
Takemi Mochida Toshitaka Kimura Sadao Hiroya Norimichi Kitagawa Hiroaki Gomi Tadahisa Kondo 《PloS one》2013,8(7)
Speech perception is thought to be linked to speech motor production. This linkage is considered to mediate multimodal aspects of speech perception, such as audio-visual and audio-tactile integration. However, direct coupling between articulatory movement and auditory perception has been little studied. The present study reveals a clear dissociation between the effects of a listener’s own speech action and the effects of viewing another’s speech movements on the perception of auditory phonemes. We assessed the intelligibility of the syllables [pa], [ta], and [ka] when listeners silently and simultaneously articulated syllables that were congruent/incongruent with the syllables they heard. The intelligibility was compared with a condition where the listeners simultaneously watched another’s mouth producing congruent/incongruent syllables, but did not articulate. The intelligibility of [ta] and [ka] were degraded by articulating [ka] and [ta] respectively, which are associated with the same primary articulator (tongue) as the heard syllables. But they were not affected by articulating [pa], which is associated with a different primary articulator (lips) from the heard syllables. In contrast, the intelligibility of [ta] and [ka] was degraded by watching the production of [pa]. These results indicate that the articulatory-induced distortion of speech perception occurs in an articulator-specific manner while visually induced distortion does not. The articulator-specific nature of the auditory-motor interaction in speech perception suggests that speech motor processing directly contributes to our ability to hear speech. 相似文献
113.
Yasunori Yamamoto Sumiko Mochida Takao Kurooka Toshiaki Sakisaka 《The Journal of biological chemistry》2009,284(18):12480-12490
Neurotransmitter release from presynaptic nerve terminals is regulated by
SNARE complex-mediated synaptic vesicle fusion. Tomosyn, a negative regulator
of neurotransmitter release, which is composed of N-terminal WD40 repeats, a
tail domain, and a C-terminal VAMP-like domain, is known to inhibit SNARE
complex formation by sequestering target SNAREs (t-SNAREs) upon interaction of
its C-terminal VAMP-like domain with t-SNAREs. However, it remains unclear how
the inhibitory activity of tomosyn is regulated. Here we show that the tail
domain functions as a regulator of the inhibitory activity of tomosyn through
intramolecular interactions. The binding of the tail domain to the C-terminal
VAMP-like domain interfered with the interaction of the C-terminal VAMP-like
domain with t-SNAREs, and thereby repressed the inhibitory activity of tomosyn
on the SNARE complex formation. The repressed inhibitory activity of tomosyn
was restored by the binding of the tail domain to the N-terminal WD40 repeats.
These results indicate that the probable conformational change of tomosyn
mediated by the intramolecular interactions of the tail domain controls its
inhibitory activity on the SNARE complex formation, leading to a regulated
inhibition of neurotransmitter release.Synaptic vesicles are transported to the presynaptic plasma membrane where
Ca2+ channels are located. Depolarization induces Ca2+
influx into the cytosol of nerve terminals through the Ca2+
channels, and this Ca2+ influx initiates the fusion of the vesicles
with the plasma membrane, finally leading to exocytosis of neurotransmitters
(1). Soluble
N-ethylmaleimide-sensitive fusion protein attachment protein
(SNAP)2
receptors (SNAREs) are essential for synaptic vesicle exocytosis
(2-5).
Synaptic vesicles are endowed with vesicle-associated membrane protein 2
(VAMP-2) as a vesicular SNARE, whereas the presynaptic plasma membrane is
endowed with syntaxin-1 and SNAP-25 as target SNAREs. VAMP-2 interacts with
SNAP-25 and syntaxin-1 to form a stable SNARE complex
(6-9).
The formation of the SNARE complex then brings synaptic vesicles and the
plasma membrane into close apposition, and provides the energy that drives the
mixing of the two lipid bilayers
(3-5,
9).Tomosyn is a syntaxin-1-binding protein that we originally identified
(10). Tomosyn contains
N-terminal WD40 repeats, a tail domain, and a C-terminal domain homologous to
VAMP-2. The C-terminal VAMP-like domain (VLD) of tomosyn acts as a SNARE
domain that competes with VAMP-2. Indeed, a structural study of the VLD
revealed that the VLD, syntaxin-1, and SNAP-25 assemble into a SNARE
complex-like structure (referred to as tomosyn complex hereafter)
(11). Tomosyn inhibits SNARE
complex formation by sequestering t-SNAREs through the tomosyn complex
formation, and thereby inhibits SNARE-dependent neurotransmitter release. The
large N-terminal region of tomosyn shares similarity to the
Drosophila tumor suppressor lethal giant larvae (Lgl), the mammalian
homologues M-Lgl1 and M-Lgl2, and yeast proteins Sro7p and Sro77p
(12,
13). Consistent with the
function of tomosyn, Lgl family members play an important role in polarized
exocytosis by regulating SNARE function on the plasma membrane in yeast and
epithelial cells (12,
13). However, only tomosyn,
Sro7, and Sro77 have the tail domains and the VLDs, suggesting that their
structural regulation is evolutionally conserved. Recently, the crystal
structure of Sro7 was solved and revealed that the tail domain of Sro7 binds
its WD40 repeats (14). Sec9, a
yeast counterpart of SNAP-25, also binds the WD40 repeats of Sro7. This
binding inhibits the SNARE complex formation and exocytosis by sequestering
Sec9. In addition, binding of the tail domain to the WD40 repeats causes a
conformational change of Sro7 and prevents the interaction of the WD40 repeats
with Sec9, leading to regulation of the inhibitory activity of Sro7 on the
SNARE complex formation (14).
However, the solved structure of Sro7 lacks its VLD. Therefore, involvement of
the activity of the VLD in the conformational change of Sro7 remains
elusive.Genetic studies in Caenorhabditis elegans showed that TOM-1, an
ortholog of vertebrate tomosyn, inhibits the priming of synaptic vesicles, and
that this priming is modulated by the balance between TOM-1 and UNC-13
(15,
16). Tomosyn was also shown to
be involved in inhibition of the exocytosis of dense core granules in adrenal
chromaffin cells and PC12 cells
(17,
18). Thus, evidence is
accumulating that tomosyn acts as a negative regulator for formation of the
SNARE complex, thereby inhibiting various vesicle fusion events. However, the
precise molecular mechanism regulating the inhibitory action of tomosyn has
yet to be elucidated.In the present study, we show that the tail domain of tomosyn binds both
the WD40 repeats and the VLD and functions as a regulator for the inhibitory
activity of tomosyn on the SNARE complex formation. Our results indicate that
the probable conformational change of tomosyn mediated by the intramolecular
interactions of the tail domain serves for controlling the inhibitory activity
of the VLD. 相似文献
114.
Background
Digital polymerase chain reaction (dPCR) is an increasingly popular technology for detecting and quantifying target nucleic acids. Its advertised strength is high precision absolute quantification without needing reference curves. The standard data analytic approach follows a seemingly straightforward theoretical framework but ignores sources of variation in the data generating process. These stem from both technical and biological factors, where we distinguish features that are 1) hard-wired in the equipment, 2) user-dependent and 3) provided by manufacturers but may be adapted by the user. The impact of the corresponding variance components on the accuracy and precision of target concentration estimators presented in the literature is studied through simulation.Results
We reveal how system-specific technical factors influence accuracy as well as precision of concentration estimates. We find that a well-chosen sample dilution level and modifiable settings such as the fluorescence cut-off for target copy detection have a substantial impact on reliability and can be adapted to the sample analysed in ways that matter. User-dependent technical variation, including pipette inaccuracy and specific sources of sample heterogeneity, leads to a steep increase in uncertainty of estimated concentrations. Users can discover this through replicate experiments and derived variance estimation. Finally, the detection performance can be improved by optimizing the fluorescence intensity cut point as suboptimal thresholds reduce the accuracy of concentration estimates considerably.Conclusions
Like any other technology, dPCR is subject to variation induced by natural perturbations, systematic settings as well as user-dependent protocols. Corresponding uncertainty may be controlled with an adapted experimental design. Our findings point to modifiable key sources of uncertainty that form an important starting point for the development of guidelines on dPCR design and data analysis with correct precision bounds. Besides clever choices of sample dilution levels, experiment-specific tuning of machine settings can greatly improve results. Well-chosen data-driven fluorescence intensity thresholds in particular result in major improvements in target presence detection. We call on manufacturers to provide sufficiently detailed output data that allows users to maximize the potential of the method in their setting and obtain high precision and accuracy for their experiments.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2105-15-283) contains supplementary material, which is available to authorized users. 相似文献115.
Identification of thermoacidophilic bacteria and a new Alicyclobacillus genomic species isolated from acidic environments in Japan 总被引:1,自引:0,他引:1
Goto K Tanimoto Y Tamura T Mochida K Arai D Asahara M Suzuki M Tanaka H Inagaki K 《Extremophiles : life under extreme conditions》2002,6(4):333-340
Sixty strains of thermoacidophilic bacteria have been isolated from soil and water samples obtained from various acidic environments in Japan. An initial comparative sequence analysis of the hypervariable regions of the 16S rDNA revealed that all strains could be assigned to the Alicyclobacillus acidocaldarius- Alicyclobacillus genomic species 1 group, which could be further subdivided into three clusters (Clusters I-III). On the basis of phenotypic characteristics, chemotaxonomic profiles, and phylogenetic data of six selected strains, five strains were identified as either A. acidocaldarius or Alicyclobacillus genomic species 1; however, one strain (MIH 332) could not be determined to belong to either of these species. 16S rDNA sequence homology values between strain MIH 332 and the reference strains of A. acidocaldarius (ATCC 27009(T)) and Alicyclobacillus genomic species 1 (DSM 11984) were 98.8% and 99.1%, respectively, which were higher than the corresponding similarity between the reference strains (98.4%). On the other hand, DNA-DNA hybridization levels between strain MIH 332 and the reference strains were 39% and 44%, respectively, which were lower than the value between the reference strains (59% or 65%). However, the phenotype of strain MIH 332 was also similar to those of the reference strains, and a typical phenotype could not be found for the strain, thus indicating that the strain may be a new genomic species of A. acidocaldarius, for which the name Alicyclobacillus genomic species 2 is tentatively proposed. The results of this study suggest that A. acidocaldarius and its related species are widely distributed in acidic environments in Japan, with slight regional variations in morphological and genotypic characteristics. 相似文献
116.
Recently, it was confirmed that embryos derived from diapausing eggs of the silkworm, Bombyx mori, begin their development and reach larval maturity on mulberry leaves, when the naked eggs are cultured in vitro. In this study, we found that the method of embryo culture is useful for determining the physiological regulation of diapause. We show that the development of embryos derived from diapausing eggs was strongly inhibited by the addition of either sorbitol or trehalose to the culture medium. Furthermore, this inhibitory effect disappeared when the embryos were cultured in a control medium which did not contain either sorbitol or trehalose, indicating that the inhibitory reactions caused by both substances are reversible. The minimal effective dose of either sorbitol or trehalose was approximately 0.2 M, a value similar to the in vivo concentration of sorbitol in diapausing eggs (0.2 M). Glycerol, mannitol or glucose were moderately effective for inhibition. Sorbitol present in diapausing silkworm eggs does not appear to serve as an antifreeze, but as an strong arresting factor of embryonic development. Furthermore, these results show that a decrease in sorbitol releases the embryos from diapause at the termination of diapause. 相似文献
117.
Shi F Mochida K Ogura A Matsuda J Suzuki O Watanabe G Hutz RJ Tsonis CG Suzuki AK Taya K 《Life sciences》2000,66(25):2489-2497
Experiments were conducted to elucidate the mechanisms of active immunization against inhibin on ovarian follicular development and selection in guinea pigs. Estrous cycle was synchronized in experimental guinea pigs by implanting progesterone containing tubes. Antibodies that bound 125I-labeled bovine inhibin were produced by all guinea pigs receiving the inhibin vaccine (recombinant ovine alpha-subunit in oil emulsion) without any effects on duration of the estrous cycle. Active immunization against inhibin increased the plasma concentrations of progesterone during the luteal phase and the plasma concentrations of estradiol but failed to increase the plasma concentration of follicle-stimulating hormone (FSH) during preovulatory period. The treatment also increased the number of corpora lutea (from 1.3+/-0.3 to 7.0+/-1.6 per each ovary), and preovulatory sized follicles (from 1.8+/-0.6 to 7.0+/-1.6 per each ovary), and follicles stained positively for inhibin alpha-subunit (from 2.3+/-0.5 to 6.3+/-1.3 per each ovary) significantly. The results indicate that active immunization against inhibin enhances ovulation rate by affecting the follicle selection and only dominant follicle can be stained for inhibin alpha-subunit in guinea pigs. This study is firstly to provide direct evidence that inhibins play important role in follicle selections in guinea pigs. 相似文献
118.
119.
Inhibition of neurotransmitter release by botulinum neurotoxins and tetanus toxin at Aplysia synapses: role of the constituent chains 总被引:5,自引:0,他引:5
B Poulain S Mochida J D Wadsworth U Weller E Habermann J O Dolly L Tauc 《Journal de physiologie》1990,84(4):247-261
1. The effects on the release of transmitter by botulinum neurotoxins (BoNT; types A, B, E), tetanus toxin (TeTx), constituent chains or fragments were studied on identified cholinergic and non-cholinergic synapses in Aplysia. 2. Cholinergic synapses in the buccal ganglion were found to be greater than 100 fold more sensitive to extracellular application of BoNT than to TeTx whereas in non-cholinergic synapses of the cerebral ganglion the potencies of the toxins were reversed. When intracellularly applied TeTx and BoNT were found nearly equipotent. This disparity in the susceptibilities of BoNT and TeTx to inhibit transmission was attributed to differences in the toxin's acceptors or uptake systems in the two neurone types. 3. Micro-injection into cholinergic neurones of the isolated renatured toxins' chains showed that both light and heavy chains of BoNT are intracellularly required whereas the light chain of TeTx alone is sufficient. 4. The heavy chain of BoNT as well as that of TeTx were found to mediate internalization of active moieties via its amino-terminal half. Furthermore the heavy chain of one toxin could internalize the light chain of the other. 相似文献
120.
Comparative genomics and reverse genetics analysis reveal indispensable functions of the serine acetyltransferase gene family in Arabidopsis 总被引:1,自引:0,他引:1
Watanabe M Mochida K Kato T Tabata S Yoshimoto N Noji M Saito K 《The Plant cell》2008,20(9):2484-2496
Ser acetyltransferase (SERAT), which catalyzes O-acetyl-Ser (OAS) formation, plays a key role in sulfur assimilation and Cys synthesis. Despite several studies on SERATs from various plant species, the in vivo function of multiple SERAT genes in plant cells remains unaddressed. Comparative genomics studies with the five genes of the SERAT gene family in Arabidopsis thaliana indicated that all three Arabidopsis SERAT subfamilies are conserved across five plant species with available genome sequences. Single and multiple knockout mutants of all Arabidopsis SERAT gene family members were analyzed. All five quadruple mutants with a single gene survived, with three mutants showing dwarfism. However, the quintuple mutant lacking all SERAT genes was embryo-lethal. Thus, all five isoforms show functional redundancy in vivo. The developmental and compartment-specific roles of each SERAT isoform were also demonstrated. Mitochondrial SERAT2;2 plays a predominant role in cellular OAS formation, while plastidic SERAT2;1 contributes less to OAS formation and subsequent Cys synthesis. Three cytosolic isoforms, SERAT1;1, SERAT3;1, and SERAT3;2, may play a major role during seed development. Thus, the evolutionally conserved SERAT gene family is essential in cellular processes, and the substrates and products of SERAT must be exchangeable between the cytosol and organelles. 相似文献