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排序方式: 共有356条查询结果,搜索用时 15 毫秒
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Gemma L. Moir-Meyer John F. Pearson Felicity Lose Rodney J. Scott Mark McEvoy John Attia Elizabeth G. Holliday Paul D. Pharoah Alison M. Dunning Deborah J. Thompson Douglas F. Easton Amanda B. Spurdle Logan C. Walker The Australian National Endometrial Cancer Study Group The Hunter Community Study Studies of Epidemiology Risk Factors in Cancer Heredity 《Human genetics》2015,134(3):269-278
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We have broadly defined the DNA regions regulating esterase6 activity in
several life stages and tissue types of D. melanogaster using P-
element-mediated transformation of constructs that contain the esterase6
coding region and deletions or substitutions in 5' or 3' flanking DNA.
Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and
the primary sequences regulating its activity lie between -171 and -25 bp
relative to the translation initiation site: deletion of these sequences
decrease activity approximately 20-fold. Hemolymph activity is also
modulated by four other DNA regions, three of which lie 5' and one of which
lies 3' of the coding region. Of these, two have positive and two have
negative effects, each of approximately twofold. Esterase6 activity is
present also in two male reproductive tract tissues; the ejaculatory bulb,
which is another ancestral activity site, and the ejaculatory duct, which
is a recently acquired site within the melanogaster species subgroup.
Activities in these tissues are at least in part independently regulated:
activity in the ejaculatory bulb is conferred by sequences between -273 and
-172 bp (threefold decrease when deleted), while activity in the
ejaculatory duct is conferred by more distal sequences between -844 and
-614 bp (fourfold decrease when deleted). The reproductive tract activity
is further modulated by two additional DNA regions, one in 5' DNA (-613 to
-284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to
+2731 bp; threefold decrease when deleted) that probably overlaps the
adjacent esteraseP gene. Collating these data with previous studies
suggests that expression of EST6 in the ancestral sites is mainly regulated
by conserved proximal sequences while more variable distal sequences
regulate expression in the acquired ejaculatory duct site.
相似文献
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Total body burdens of Zn, Pb, Al and Cu were measured in Swedish marine nemerteans sampled from an area close to a major source
of pollution. Accumulation patterns varied both seasonally and spatially. The results suggest that nemerteans may be useful
bioindicator species in environmental monitoring programmes. 相似文献
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C Möller G Weber MM Dreyfuss 《Journal of industrial microbiology & biotechnology》1996,17(5-6):359-372
Intraspecific variation among 84 isolates of the anamorphic fungusChaunopycnis alba from 26 different geographical locations was analyzed by investigating optimal growth temperatures, differences in the production of secondary metabolites and presence or absence of the cyclosporin synthetase gene. The genetic diversity was assessed using random amplified polymorphic DNA (RAPD). Analysis of these data showed high genetic, metabolic and physiological diversity within this species. Isolates from the Antarctic represented the most homogeneous group withinC. alba and together with isolates from the Arctic these polar strains differed from alpine, temperate and tropical strains by low optimal growth temperatures and by low production of secondary metabolites. Isolates from tropical climes were characterized by high optimal growth temperatures and by the production of comparatively diverse metabolite spectra. Most of the isolates that were similar in the combination of their physiological and metabolic characters were also genetically related. Isolates from different geographical origins did not show many similarities, with the exception of the cyclosporin A-producing isolates, and large diversity could be observed even within a single habitat. This leads us to the suggestion that for pharmaceutical screening programs samples should be collected from a diversity of different geographical and climatic locations. For the selection of strains for screening the RAPD assay seems to be the most powerful tool. It reflected the highest intraspecific diversity and the results corresponded well with the other characteristics. 相似文献
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Sajkov Dimitar; Neill Alister; Saunders Nicholas A.; McEvoy R. Douglas 《Journal of applied physiology》1997,83(2):599-607
Sajkov, Dimitar, Alister Neill, Nicholas A. Saunders, and R. Douglas McEvoy. Comparison of the effects of sustained isocapnichypoxia on ventilation in men and women. J. Appl.Physiol. 83(2): 599-607, 1997.Sleep-relatedrespiratory disturbances are more common in men than in premenopausalwomen. This might, in part, be due to different susceptibilities to therespiratory depressant effects of hypoxia. Therefore, we comparedventilation during 10 min of baseline room-air breathing and 20-minsustained isocapnic hypoxia (fractional inspiredO2 = 11%, arterial saturation ofO2 80%) followed by 10 min ofbreathing 100% O2 in 10 normal men and in 10 women in the follicular phase of the menstrual cycle. Control measurements were made during two transitions from room air (10 min) to 100% O2 (10 min) andaveraged. Inspired minute ventilation(I) after2 min of hypoxia was the same in men and women [131 ± 6.1%baseline for men, 136 ± 7.7% baseline for women; not significant(NS)] and declined to the same level after 20 min (115 ± 5.0% baseline for men, 116 ± 6.6% baseline for women; NS)associated with a similar decline in inspiratory time and tidal volume.Breathing frequency did not change.I decreased transiently during subsequent 100%O2 breathing in both men and women, associated with reduced frequency and duty cycle and increased expiratory time. The fall inI wassignificantly greater than that observed during control hyperoxiaexperiments in men but not in women. We conclude that ventilatoryresponses to sustained isocapnic hypoxia do not differ between awakehealthy men and women in the follicular phase of their menstrual cycle.However, after termination of isocapnic hypoxia, men appear to depress their ventilation to a greater degree than women. 相似文献
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R C McEvoy 《Differentiation; research in biological diversity》1980,17(2):105-109
Eighteen-day-old rat fetal pancreas was grown in organ culture for four days on medium consisting of tissue culture Medium 199 and varying concentrations of chicken serum. The glucagon and somatostatin concentration of the explants was decreased when the serum concentration of the medium was reduced from 50 to 10%. There was a further reduction in these hormones when the explants were cultured on Medium 199 alone. Explant insulin content was reduced only when serum was omitted from the medium. A "serum factor" tripeptide was not able to substitute for this serum requirement. Heat-inactivation of the serum resulted in a significant increase in medium insulin content and an increase in both the insulin and glucagon contents of the explants. This increase in hormone content was directly correlated with increases in the beta and alpha cell volumes of the explants. There was no change in the somatostatin content or delta cell volume of the explants grown on heat-inactivated medium. It is suggested that the serum is an important component of the culture media and is apparently required in high concentration for the development of the islet cells in vitro. The islet cell types differ in their requirement for serum. The alpha and delta a higher concentration than do the beta cells. 相似文献
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