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排序方式: 共有247条查询结果,搜索用时 15 毫秒
191.
Alain D. Silk Charles E. Gast Paige S. Davies Farnaz D. Fakhari Gretchen E. Vanderbeek Motomi Mori Melissa H. Wong 《PloS one》2013,8(1)
Following transplantation of hematopoietic lineage cells, genetic markers unique to the transplanted cells have been detected in non-hematopoietic recipient cells of human liver, vascular endothelium, intestinal epithelium and brain. The underlying mechanisms by which this occurs are unclear. Evidence from mice suggests it is due in part to fusion between cells of hematopoietic and non-hematopoietic origins; however, direct evidence for this in humans is scant. Here, by quantitative and statistical analysis of X- and Y-chromosome numbers in epithelial and non-epithelial intestinal cells from gender-mismatched hematopoietic cell transplant patients, we provide evidence that transplanted cells of the hematopoietic lineage incorporate into human intestinal epithelium through cell fusion. This is the first definitive identification of cell fusion between hematopoietic cells and any epithelial cell type in humans, and provides the basis for further understanding the physiological and potential pathological consequences of cell fusion in humans. 相似文献
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Ryall KL Silk PJ Mayo P Crook D Khrimian A Cossé AA Sweeney J Scarr T 《Environmental entomology》2012,41(3):648-656
Attraction of emerald ash borer, Agrilus planipennis Fairmaire, to a volatile pheromone was demonstrated in three field experiments using baited green sticky traps. A dose-response curve was generated for male A. planipennis to increasing release rates of (3Z)-dodecen-12-olide ((3Z)-lactone) in combination with the green leaf volatile, (3Z)-hexenol. Only the lowest release rate (<2.50 μg/d) of (3Z)-lactone significantly increased captures of male A. planipennis, as compared with traps baited with (3Z)-hexenol alone. Effect of trap height, (3Z)-lactone, and (3Z)-hexenol and their interactions on the trap capture of A. planipennis was determined in a factorial experiment. Number of males per trap was significantly and positively affected by (3Z)-lactone, (3Z)-hexenol, and trap height whereas number of females per trap was affected by trap height only; none of the interactions were significant. As predicted, the greatest mean catch of males was in traps baited with (3Z)-lactone and (3Z)-hexenol placed high in the canopy. Electroantennogram tests on the bark volatile, 7-epi-sesquithujene, demonstrated the ability of male and female A. planipennis antennae to detect and respond to this compound, particularly the (+)-7-epi-sesquithujene isomer. Results from an olfactometer bioassay and field testing did not demonstrate attraction of either males or females to (+)-7-epi-sesquithujene. These data increase our understanding of the pheromone ecology of the invasive emerald ash borer, provide further confirmation of the behavioral activity of the female-produced lactone pheromone, and should increase the ability to detect A. planipennis infestations where they are present. 相似文献
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Silk JB 《Current biology : CB》2007,17(2):R50-R51
Conflict is a fact of life in social species. New data from birds enhance our understanding of how and why evolution has favored mechanisms to resolve disputes and manage conflicts. 相似文献
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Joan B. Silk 《International journal of primatology》1986,7(6):583-602
Variation in environmental conditions during pregnancy and differences in the feeding behavior of females during pregnancy
were consistently associated with variation in gestation length among free-ranging yellow baboons, Papio cynocephalus,in Amboseli National Park, Kenya. Females whose pregnancies ended during the wet season gave birth after shorter pregnancies
than females whose pregnancies ended during the dry season. When rainfall is held constant, another source of variation in
gestation length emerges. Females that spent progressively less time feeding over the course of their pregnancies gave birth
after longer pregnancies than females that spent progressively more time feeding over the course of their pregnancies. These
two factors, which provide rough indices of maternal nutritional status, accounted for a substantial fraction of the observed
variation in gestation length among these female baboons. 相似文献
200.
The interactions of horse spleen ferritin and its derivative apoferritin with H+ ions were studied by potentiometric and spectrophotometric titration; to aid in data analysis, heats of ionization over a limited pH range and amide content were also determined. Per apoferritin subunit, all tyrosine and cysteine side chains, two of the nine lysine side chains and at least three of the six histidine side chains were found not to titrate; a preliminary but self-consistent analysis of the titration data is proposed. The titration curve of ferritin was identical with that of apoferritin in the pH range 5.5 to 3. In addition, under the conditions used, the reactivities of ferritin histidines to bromoacetate and of ferritin lysines to formaldehyde were identical with those in apoferritin. Above pH 8, a time-dependent titration of the ferritin core occurs which prevents comparison of the titration curves of the two proteins in this region. However, in the pH regions 5.5 to 7.5, two extra groups per subunit titrate reversibly in ferritin relative to apoferritin. Moreover, although the isoionic points of ferritin and apoferritin are identical in water, the isoionic point of ferritin is 0.5 pH unit lower than that of apoferritin in 0.16 to 1 M KCl. The different effects of KCl and NaCl on the two proteins indicate the presence of cation binding sites in ferritin that are absent in apoferritin and possibly also the presence of anion binding sites in apoferritin that are occupied in ferritin by anions of the core. The difference between the isoionic points of the two proteins in KCl has been interpreted to indicate the presence of approximately 2 phosphate residues per ferritin subunit which serve as cation binding sites and which are negatively charged at the isoionic point in KCl. These phosphates may also represent the additional residues that titrate in ferritin between pH 5.5 and 7.5, or may interact with positively charged residues on the inner surface of the ferritin shell, or both. 相似文献