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991.
Connell E Darios F Broersen K Gatsby N Peak-Chew SY Rickman C Davletov B 《EMBO reports》2007,8(4):414-419
Syntaxin and Munc18 are, in tandem, essential for exocytosis in all eukaryotes. Recently, it was shown that Munc18 inhibition of neuronal syntaxin 1 can be overcome by arachidonic acid, indicating that this common second messenger acts to disrupt the syntaxin-Munc18 interaction. Here, we show that arachidonic acid can stimulate syntaxin 1 alone, indicating that it is syntaxin 1 that undergoes a structural change in the syntaxin 1-Munc18 complex. Arachidonic acid is incapable of dissociating Munc18 from syntaxin 1 and, crucially, Munc18 remains associated with syntaxin 1 after arachidonic-acid-induced syntaxin 1 binding to synaptosomal-associated protein 25 kDa (SNAP25). We also show that the same principle operates in the case of the ubiquitous syntaxin 3 isoform, highlighting the conserved nature of the mechanism of arachidonic acid action. Neuronal soluble N-ethyl maleimide sensitive factor attachment protein receptors (SNAREs) can be isolated from brain membranes in a complex with endogenous Munc18, consistent with a proposed function of Munc18 in vesicle docking and fusion. 相似文献
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Hornillo-Araujo AR Burrell AJ Aiertza MK Shibata T Hammond DM Edmont D Adams H Margison GP Williams DM 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):1099-1102
The syntheses of novel tricyclic pyrrolo[2,3-d]pyrimidine analogues of O(6)-methylguanine and S(6)-methylthioguanine are described. The crystal structures and pK(a) values of these analogues are reported. In a standard substrate assay with the human repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) only the oxygen-containing analogue displayed activity. 相似文献
994.
Rohal Christine B. Adams Carrie Reinhardt Martin Charles W. Tevlin Sarah Reynolds Laura K. 《Hydrobiologia》2022,849(16):3481-3500
Hydrobiologia - Potamogeton illinoensis is a North American macrophyte, commonly the focus of management, but limited knowledge of its life history hampers conservation and restoration efforts. We... 相似文献
995.
Benitt Colin Young Craig S. Sylvers Laine H. Gobler Christopher J. 《Journal of applied phycology》2022,34(2):965-983
Journal of Applied Phycology - Harmful algal blooms (HABs) caused by the pelagophyte Aureococcus anophagefferens have spread globally and are a threat to coastal ecosystems. Although some HAB... 相似文献
996.
Evolutionary Ecology - Sexual dimorphism is a common feature in animals, yet the degree of sexual dimorphism is not constant across taxa. Sometimes the magnitude of sexual dimorphism varies... 相似文献
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The resemblance between palatable mimics and unpalatable models in Batesian mimicry systems is tempered by many factors, including the toxicity of the model species. Model toxicity is thought to influence both the occurrence of mimicry and the evolution of mimetic phenotypes, such that mimicry is most likely to persist when models are particularly toxic. Additionally, model toxicity may influence the evolution of mimetic phenotype by allowing inaccurate mimicry to evolve through a mechanism termed ‘relaxed selection’. We tested these hypotheses in a salamander mimicry system between the model Notophthalmus viridescens and the mimic Plethodon cinereus, in which N. viridescens toxicity takes the form of tetrodotoxin. Surprisingly, though we discovered geographic variation in model toxin level, we found no support for the hypotheses that model toxicity directly influences either the occurrence of mimicry or the evolution of mimic phenotype. Instead, a link between N. viridescens size and toxicity may indirectly lead to relaxed selection in this mimicry system. Additionally, limitations of predator perception or variation in the rate of phenotypic evolution of models and mimics may account for the evolution of imperfect mimicry in this salamander species. Finally, variation in predator communities among localities or modern changes in environmental conditions may contribute to the patchy occurrence of mimicry in P. cinereus. 相似文献