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731.
Vicki L. Medland Naida Zucker & Stephen C. Weeks 《Ethology : formerly Zeitschrift fur Tierpsychologie》2000,106(9):839-848
Androdioecy is a mixed‐mating system in which there are males and hermaphrodites but no pure females. Few species exhibit such a mating system. Eulimnadia texana is a branchiopod crustacean that has recently been identified as an androdioecious species. This system is ideal for testing questions related to the evolution of sexual reproduction. We are testing a model that predicts androdioecy to be a stable mixed‐mating system under certain conditions. Specifically, we investigated whether encounters between males and hermaphrodites are random or if either sex seeks out the other for mating. Focal male or hermaphrodite clam shrimp were presented with stimulus shrimp of the other sex or kept alone. Swimming speed and time spent within different areas of a test chamber were recorded. Males did not alter mean swimming speed or spend more time than expected by chance near partitioned hermaphrodites. Hermaphrodites, however, decreased mean swimming speed in the presence of males and also spent more time than expected by chance near partitioned males, suggesting that hermaphrodites respond to male chemical and/or visual stimuli. Modified swimming behaviour probably facilitates inter‐sexual contact, thereby increasing opportunities for out‐crossing above that expected by random encounters. 相似文献
732.
Larry W. Daniel Vicki A. Sciorra Sujoy Ghosh 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》1999,1439(2):265-276
Phosphatidylcholine hydrolysis by phospholipase D is a widespread response to cellular stimulation. However, the downstream signaling events subsequent to phosphatidylcholine hydrolysis are just beginning to be determined. Initially it was proposed that diglyceride formation by phospholipase D and phosphatidate phosphohydrolase resulted in long-term stimulation of protein kinase C. However, recent studies indicate that phosphatidic acid is the relevant signaling molecule in some signaling pathways. The present review will summarize studies of phospholipase D in the response of cells to the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate, which causes cells to mimic the phenotype of oncogenic transformation. The role of phospholipase D in stimulation of Raf-1 and prostaglandin H synthase type-2 is emphasized. 相似文献
733.
Vicki Zhou 《Analytical biochemistry》2009,385(2):300-361
Conformational change is a common molecular mechanism for the regulation of kinase activities. Small molecule modulators of protein conformations, including allosteric kinase inhibitors, are highly wanted as tools for the interrogation of kinase biology and as selective therapeutic agents. However, straightforward cellular assays monitoring kinase conformations in a manner conducive to high-throughput screening (HTS) are not readily available. Here we describe such an HTS-compatible conformational sensor assay for Abl based on a split luciferase construct. The Abl sensor responds to intramolecular structural rearrangements associated with intracellular Abl deactivation and small molecule inhibition. The intact regulatory CAP-SH3-SH2 domain is required for the full functionality of the sensor. Moreover, a T334I Abl mutant (T315I in Abl1a) was found to be particularly well suited for HTS purposes and mechanistic intracellular studies of T334I mutant inhibitors. We expect that the split luciferase-based conformational sensor approach might be more broadly useful to probe the intracellular activation of other kinases and enzymes in general. 相似文献
734.
Play behaviours of northern grasshopper mice, , were observed from 27 to 61 days of age and after a brief period of social isolation. The mice were also observed during a simple test of cricket predation. With the exception of an active play-soliciting response, the play behaviours were quite similar to those described for other rodents. Play declined with increasing age and was strongly potentiated by social isolation. There was no discernable relationship between any of the play measures and efficiency of cricket predation. There were no detectable sex differences in either play or predation. 相似文献
735.
This report is a comprehensive fine structural analysis of the morphological changes occurring during metamorphosis of the marine hydrozoan Mitrocomella polydiademata. Five stages are recognized during metamorphosis: planulae just prior to settlement, ball and filiform stages, immature polyps, and primary feeding polyps. Settlement and metamorphosis of cnidarian planulae involve such changes as ciliary arrest, discharge of nematocytes, secretion of glandular cells, differentiation of cells, and changes in cell and body shape. 相似文献
736.
Ragnar Berger Synnøve Liaaen-Jensen Vicki McAlister Robert R.L. Guillard 《Biochemical Systematics and Ecology》1977,5(2):71-75
A quantitative study, including mass spectrometric identification, of the carotenoids isolated from some selected prymnesiophytes harvested in exponential growth phase has been carried out. Isochrysis galbana, Hymenomonas carterae, Prymnesium parvum, Pavlova (Monochrysis) lutheri and a Pavlova sp. all produce β,β-carotene, diatoxanthin, diadinoxanthin and fucoxanthin (major carotenoid) in various proportions, in addition to several minor carotenoids were found characteristic of each alga. 19'-Hexanoyloxyfucoxanthin, previously shown to be the major carotenoid in the prymnesiophyte Emeliana (Coccolithus) huxleyi, was not encountered in the Prymnesiophyceae studied here, and we conclude that this carotenoid should be critically looked for in other members of the Gephyrocapsaceae to which E. huxleyi belongs. We further conclude that the carotenoid complement of the Chrysophyceae (in the narrow sense) should be compared with that of the Prymnesiophyceae. 相似文献
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International Journal of Primatology - 相似文献