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991.
992.
Stephen C. Thornquist Maximilian J. Pitsch Charlotte S. Auth Michael A. Crickmore 《Molecular cell》2021,81(4):675-690.e8
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993.
994.
995.
Herv Hoste Robin B. Gasser Neil B. Chilton Serge Mallet Ian Beveridge 《International journal for parasitology》1993,23(8):1069-1071
The nucleotide sequence of the second internal transcribed spacer (ITS-2) was determined for three populations of the parasitic nematode Trichostrongylus colubriformis which differed in their susceptibility to benzimidazole anthelmintics and/or in their geographical origin. No intraspecific variation was found in the ITS-2 sequence, indicating that this region of rDNA is inadequate to discriminate between resistant and susceptible populations of T. colubriformis, but it may prove useful for distinguishing between species of Trichostrongylus. 相似文献
996.
Rats given either intragastric or intraventricular injections of clozapine showed a dose-dependent increase in food intake. 相似文献
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998.
Wing-Kit Leung Neil Humphryes Negar Afshar Bilge Argunhan Yaroslav Terentyev Tomomi Tsubouchi Hideo Tsubouchi 《The Journal of cell biology》2015,211(4):785-793
During meiotic prophase I, proteinaceous structures called synaptonemal complexes (SCs) connect homologous chromosomes along their lengths via polymeric arrays of transverse filaments (TFs). Thus, control of TF polymerization is central to SC formation. Using budding yeast, we show that efficiency of TF polymerization closely correlates with the extent of SUMO conjugation to Ecm11, a component of SCs. HyperSUMOylation of Ecm11 leads to highly aggregative TFs, causing frequent assembly of extrachromosomal structures. In contrast, hypoSUMOylation leads to discontinuous, fragmented SCs, indicative of defective TF polymerization. We further show that the N terminus of the yeast TF, Zip1, serves as an activator for Ecm11 SUMOylation. Coexpression of the Zip1 N terminus and Gmc2, a binding partner of Ecm11, is sufficient to induce robust polySUMOylation of Ecm11 in nonmeiotic cells. Because TF assembly is mediated through N-terminal head-to-head associations, our results suggest that mutual activation between TF assembly and Ecm11 polySUMOylation acts as a positive feedback loop that underpins SC assembly. 相似文献
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1000.
Neil H. Landman Kristin Polizzotto Royal H. Mapes Kazushige Tanabe 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2006,39(4):365-379
We describe cameral membranes in prolecanitid and goniatitid ammonoids from the Lower Permian Arcturus Formation, Nevada, USA. The membranes are preserved as phosphatic sheets and were originally composed of organic material such as conchiolin. Because the phragmocones are filled with micritic calcite, the cameral membranes can be exposed by etching with weak acetic acid. The membranes are associated with the siphuncle and also coat the septal faces and chamber walls. The siphuncular membranes are much more extensive in the prolecanitids than in the goniatites. These membranes appear in the prolecanitids at the beginning of the third whorl, corresponding to a shell diameter of 3-4 mm, and become more complex through ontogeny. Additional membranes, called transverse membranes, appear in some of the septal saddles on the ventrolateral side. The siphuncular membranes in prolecanitids are very similar to those in the Ceratitina plus Mesozoic Ammonoidea, suggesting that such membranes are widely distributed in this group. However, the origin and function of these membranes are unclear. We argue that the siphuncular membranes were sequentially secreted by the rear mantle during forward movement of the body and were not produced by desiccation of cameral liquid after the formation of the chambers. The most compelling arguments for this interpretation are the abrupt appearance of these membranes at a shell diameter of approximately 3-4 mm in prolecanitids, ceratites, and ammonitids, coincident with the end of the neanic stage, and the uniform increase in complexity of the membranes through ontogeny. The shape of the siphuncular membranes in prolecanitids suggests the presence of an invagination on the dorsal side of the siphuncle during part of the chamber formation cycle. Cameral membranes may have served a variety of functions including stabilizing the cameral liquid to reduce rocking motion during swimming, anchoring the siphuncle to the chamber wall, and facilitating cameral liquid removal, permitting a faster rate of growth. 相似文献