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201.
Torres-Rosell J De Piccoli G Cordon-Preciado V Farmer S Jarmuz A Machin F Pasero P Lisby M Haber JE Aragón L 《Science (New York, N.Y.)》2007,315(5817):1411-1415
Cellular checkpoints prevent mitosis in the presence of stalled replication forks. Whether checkpoints also ensure the completion of DNA replication before mitosis is unknown. Here, we show that in yeast smc5-smc6 mutants, which are related to cohesin and condensin, replication is delayed, most significantly at natural replication-impeding loci like the ribosomal DNA gene cluster. In the absence of Smc5-Smc6, chromosome nondisjunction occurs as a consequence of mitotic entry with unfinished replication despite intact checkpoint responses. Eliminating processes that obstruct replication fork progression restores the temporal uncoupling between replication and segregation in smc5-smc6 mutants. We propose that the completion of replication is not under the surveillance of known checkpoints. 相似文献
202.
Moyà-Solà S Köhler M Alba DM Casanovas-Vilar I Galindo J 《Science (New York, N.Y.)》2004,306(5700):1339-1344
We describe a partial skeleton with facial cranium of Pierolapithecus catalaunicus gen. et sp. nov., a new Middle Miocene (12.5 to 13 million years ago) ape from Barranc de Can Vila 1 (Barcelona, Spain). It is the first known individual of this age that combines well-preserved cranial, dental, and postcranial material. The thorax, lumbar region, and wrist provide evidence of modern ape-like orthograde body design, and the facial morphology includes the basic derived great ape features. The new skeleton reveals that early great apes retained primitive monkeylike characters associated with a derived body structure that permits upright postures of the trunk. Pierolapithecus, hence, does not fit the theoretical model that predicts that all characters shared by extant great apes were present in their last common ancestor, but instead points to a large amount of homoplasy in ape evolution. The overall pattern suggests that Pierolapithecus is probably close to the last common ancestor of great apes and humans. 相似文献
203.
Shape control of inorganic nanocrystals is important for understanding basic size- and shape-dependent scaling laws and is useful in a wide range of applications. With minor modifications in the chemical environment, it is possible to control the reaction and diffusion processes at room temperature, opening up a synthetic route for the production of polymetallic hollow nanoparticles with very different morphology and composition, obtained by the simultaneous or sequential action of galvanic replacement and the Kirkendall effect. 相似文献
204.
Deficit irrigation (DI) detrimentally affected berry size but had a profound effect on fruit physiology and biochemistry. Strawberry cv. Elsanta fruit from DI-treated plants had higher levels of abscisic acid (ABA). Dry matter content as a proportion of fresh weight was increased by a quarter in fruit from water-stressed plants as compared to fruit harvested from plants held at or near field capacity. Concomitant to this, the concentration of some taste-related (viz. monosaccharides and sugar/acid ratios) and health-related compounds/parameters (viz. antioxidant capacity and total phenolics) were generally much greater in DI-treated fruit. The effect of inoculation with Botrytis cinerea on fruit quality was also tested. Fruit derived from inoculated plants displayed symptoms of gray mold postharvest disease earlier than noninoculated fruit and had double the concentration of ABA. Inoculation had no significant effects on all other target analytes measured. There was no interaction between water treatment and inoculation. The possible mechanisms for increased synthesis of ABA and the different effects of pathogen-induced stress versus drought stress on fruit quality are discussed. 相似文献
205.
Consumption of feeds containing the antibiotic sulfadiazine by gilthead sea bream (Sparus aurata,L.) and rainbow trout (Onchorynchus mykiss,Walbaum) 下载免费PDF全文
Alicia Estévez Mónica Ríus‐Francino Jordi López Joan Freixes 《Aquaculture Research》2017,48(5):2291-2302
A method for studying the efficacy of sulfadiazine as a marker to estimate feed intake is presented. Feeding studies were carried out with two species, rainbow trout as a freshwater fish model and gilthead sea bream as a marine fish model, using two temperatures and two sizes of juveniles. The study showed the different feeding behaviour observed in both species, depending on the temperature and the number of days feeding the particles with sulfadiazine, and confirmed a dominant‐subordinate behaviour especially in the case of gilthead sea bream juveniles. 相似文献