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排序方式: 共有453条查询结果,搜索用时 343 毫秒
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Spehr M Gisselmann G Poplawski A Riffell JA Wetzel CH Zimmer RK Hatt H 《Science (New York, N.Y.)》2003,299(5615):2054-2058
Although it has been known for some time that olfactory receptors (ORs) reside in spermatozoa, the function of these ORs is unknown. Here, we identified, cloned, and functionally expressed a previously undescribed human testicular OR, hOR17-4. With the use of ratiofluorometric imaging, Ca2+ signals were induced by a small subset of applied chemical stimuli, establishing the molecular receptive fields for the recombinantly expressed receptor in human embryonic kidney (HEK) 293 cells and the native receptor in human spermatozoa. Bourgeonal was a powerful agonist for both recombinant and native receptor types, as well as a strong chemoattractant in subsequent behavioral bioassays. In contrast, undecanal was a potent OR antagonist to bourgeonal and related compounds. Taken together, these results indicate that hOR17-4 functions in human sperm chemotaxis and may be a critical component of the fertilization process. 相似文献
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Muller CB Ride SM Fouke J Whitney T Denton DD Cantor N Nelson DJ Plummer J Busch-Vishniac I Meyers C Rosser SV Schiebinger L Roberts E Burgess D Beeson C Metz SS Sanders L Watford BA Ivey ES Frank Fox M Wettack S Klawe M Wulf WA Girgus J Leboy PS Babco EL Shanahan B Didion C Chubin DE Frize M Ganter SL Nalley EA Franz J Abruña HD Strober MH Zimmer Daniels J Carter EA Rhodes JH Schrijver I Zakian VA Simons B Martin U Boaler J Jolluck KR Mankekar P Gray RM Conkey MW Stansky P Xie A Martin P 《Science (New York, N.Y.)》2005,307(5712):1043
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Zimmer C 《Science (New York, N.Y.)》2002,296(5568):633-635
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Development ofHelminthosporium solani Dur. & Mont. on artificially inoculated, excised potato tuber periderm, incubated in darkness and high humidity at 20 to 24°C, was studied using light and scanning electron microscopy. Spore germination occurred within 16 hours, and appressoria were observed 2 days after inoculation. Penetration of periderm was evident 4 days after inoculation. Conidiophores with young conidia developed on the periderm surface within 7 days of inoculation. Well-developed conidia were visible often by 9 days after inoculation. Rudimentary stromata were observed beneath conidiophore groupings at later stages of development. In histological studies,H. solani hyphae were found in the phellem, phelloderm, and cortex of infected tuber sections. Basal cells of conidiophores or stromata were observed on the surface and in the outer tangential cork cell layers. Several layers of suberized and sometimes collapsed cortical cells were observed beneath disrupted and collapsed, infected periderm. Cavities sometimes formed between periderm and cortex, and callosities were observed on cell walls of some cortical cells beneath infected periderm. 相似文献