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排序方式: 共有776条查询结果,搜索用时 15 毫秒
71.
Maria C Anholeti Rodrigo C Duprat Maria R Figueiredo Maria AC Kaplan Marcelo Guerra Santos Marcelo S Gonzalez Norman A Ratcliffe Denise Feder Selma R Paiva Cicero B Mello 《Memórias do Instituto Oswaldo Cruz》2015,110(5):629-635
Studies evaluated the effects of hexanic extracts from the fruits and flowers
ofClusia fluminensis and the main component of the flower
extract, a purified benzophenone (clusianone), against Aedes
aegypti. The treatment of larvae with the crude fruit or flower extracts
from C. fluminensis did not affect the survival ofAe.
aegypti (50 mg/L), however, the flower extracts significantly delayed
development of Ae. aegypti. In contrast, the clusianone (50 mg/L) isolate from the
flower extract, representing 54.85% of this sample composition, showed a highly
significant inhibition of survival, killing 93.3% of the larvae and completely
blocking development of Ae. aegypti. The results showed, for the first time, high
activity of clusianone against Ae. aegypti that both killed and inhibited mosquito
development. Therefore, clusianone has potential for development as a biopesticide
for controlling insect vectors of tropical diseases. Future work will elucidate the
mode of action of clusianone isolated from C. fluminensis. 相似文献
72.
I‐Ching Chen Jane K. Hill Hau‐Jie Shiu Jeremy D. Holloway Suzan Benedick Vun Khen Chey Henry S. Barlow Chris D. Thomas 《Global Ecology and Biogeography》2011,20(1):34-45
Aim To estimate whether species have shifted at equal rates at their leading edges (cool boundaries) and trailing edges (warm boundaries) in response to climate change. We provide the first such evidence for tropical insects, here examining elevation shifts for the upper and lower boundaries shifts of montane moths. Threats to species on tropical mountains are considered. Location Mount Kinabalu, Sabah, Malaysia. Methods We surveyed Lepidoptera (Geometridae) on Mount Kinabalu in 2007, 42 years after the previous surveys in 1965. Changes in species upper and lower boundaries, elevational extents and range areas were assessed. We randomly subsampled the data to ensure comparable datasets between years. Estimated shifts were compared for endemic versus more widespread species, and for species that reached their range limits at different elevations. Results Species that reached their upper limits at 2500–2700 m (n= 28 species, 20% of those considered) retreated at both their lower and upper boundaries, and hence showed substantial average range contractions (?300 m in elevational extent and ?45 km2 in estimated range area). These declines may be associated with changes in cloud cover and the presence of ecological barriers (geological and vegetation transitions) which impede uphill movement. Other than this group, most species (n= 109, 80% of the species considered) expanded their upper boundaries upwards (by an average of 152 m) more than they retreated at their lower boundaries (77 m). Main conclusions Without constraints, leading margins shifted uphill faster than trailing margins retreated, such that many species increased their elevational extents. However, this did not result in increases in range area because the area of land available declines with increasing elevation. Species close to a major ecological/geological transition zone on the mountain flank declined in their range areas. Extinction risk may increase long before species reach the summit, even when undisturbed habitats are available. 相似文献
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Placental ribonuclease inhibitor (RI) binds diverse mammalian RNases with dissociation constants that are in the femtomolar range. Previous studies on the complexes of RI with RNase A and angiogenin revealed that RI utilises largely distinctive interactions to achieve high affinity for these two ligands. Here we report a 2.0 angstroms resolution crystal structure of RI in complex with a third ligand, eosinophil-derived neurotoxin (EDN), and a mutational analysis based on this structure. The RI-EDN interface is more extensive than those of the other two complexes and contains a considerably larger set of interactions. Few of the contacts present in the RI-angiogenin complex are replicated; the correspondence to the RI-RNase A complex is somewhat greater, but still modest. The energetic contributions of various interface regions differ strikingly from those in the earlier complexes. These findings provide insight into the structural basis for the unusual combination of high avidity and relaxed stringency that RI displays. 相似文献
75.
Plant-based microarray data at the European Bioinformatics Institute. Introducing AtMIAMExpress, a submission tool for Arabidopsis gene expression data to ArrayExpress 下载免费PDF全文
Mukherjee G Abeygunawardena N Parkinson H Contrino S Durinck S Farne A Holloway E Lilja P Moreau Y Oezcimen A Rayner T Sharma A Brazma A Sarkans U Shojatalab M 《Plant physiology》2005,139(2):632-636
ArrayExpress is a public microarray repository founded on the Minimum Information About a Microarray Experiment (MIAME) principles that stores MIAME-compliant gene expression data. Plant-based data sets represent approximately one-quarter of the experiments in ArrayExpress. The majority are based on Arabidopsis (Arabidopsis thaliana); however, there are other data sets based on Triticum aestivum, Hordeum vulgare, and Populus subsp. AtMIAMExpress is an open-source Web-based software application for the submission of Arabidopsis-based microarray data to ArrayExpress. AtMIAMExpress exports data in MAGE-ML format for upload to any MAGE-ML-compliant application, such as J-Express and ArrayExpress. It was designed as a tool for users with minimal bioinformatics expertise, has comprehensive help and user support, and represents a simple solution to meeting the MIAME guidelines for the Arabidopsis community. Plant data are queryable both in ArrayExpress and in the Data Warehouse databases, which support queries based on gene-centric and sample-centric annotation. The AtMIAMExpress submission tool is available at http://www.ebi.ac.uk/at-miamexpress/. The software is open source and is available from http://sourceforge.net/projects/miamexpress/. For information, contact miamexpress@ebi.ac.uk. 相似文献
76.
Edmunds KM Holloway AC Crankshaw DJ Agarwal SK Foster WG 《Reproduction, nutrition, development》2005,45(6):709-720
Dietary phytoestrogens have been reported to inhibit aromatase activity in placental microsomes, but the effects in the human endometrium are unknown. Aromatase, the rate-limiting enzyme in the conversion of androgens to estrogens, has recently been shown to be expressed in the endometrium of women with endometriosis and is thought to play a role in the pathophysiology of this disease. Therefore, the objective of this study was to screen dietary phytoestrogens for their ability to inhibit aromatase activity in human endometrial stromal cells (ESC) and identify potential novel therapeutic agents for the treatment of endometriosis. The inhibition of aromatase activity by direct interaction with the dietary phytoestrogens genistein, daidzein, chrysin, and naringenin was tested in a cell free assay. Furthermore, test compound effects on aromatase activity in ESC cultures were also examined. Genistein and daidzein were inactive in the human recombinant aromatase assay whereas naringenin and chrysin inhibited aromatase activity. However, genistein (1 nM to 1 mM) stimulated aromatase activity in ESC whereas other phytoestrogens had no effect. Immunopositive aromatase cells were demonstrated in genistein-treated ESC but not in untreated control cultures. Taken together, our data suggest that genistein can increase aromatase activity in ESC likely via increased enzyme expression. 相似文献
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Velayos-Baeza A Levecque C Kobayashi K Holloway ZG Monaco AP 《The Journal of biological chemistry》2010,285(51):40148-40162
The KIAA0319 gene has been associated with reading disability in several studies. It encodes a plasma membrane protein with a large, highly glycosylated, extracellular domain. This protein is proposed to function in adhesion and attachment and thought to play an important role during neuronal migration in the developing brain. We have previously proposed that endocytosis of this protein could constitute an important mechanism to regulate its function. Here we show that KIAA0319 undergoes ectodomain shedding and intramembrane cleavage. At least five different cleavage events occur, four in the extracellular domain and one within the transmembrane domain. The ectodomain shedding processing cleaves the extracellular domain, generating several small fragments, including the N-terminal region with the Cys-rich MANEC domain. It is possible that these fragments are released to the extracellular medium and trigger cellular responses. The intramembrane cleavage releases the intracellular domain from its membrane attachment. Our results suggest that this cleavage event is not carried out by γ-secretase, the enzyme complex involved in similar processing in many other type I proteins. The soluble cytoplasmic domain of KIAA0319 is able to translocate to the nucleus, accumulating in nucleoli after overexpression. This fragment has an unknown role, although it could be involved in regulation of gene expression. The absence of DNA-interacting motifs indicates that such a function would most probably be mediated through interaction with other proteins, not by direct DNA binding. These results suggest that KIAA0319 not only has a direct role in neuronal migration but may also have additional signaling functions. 相似文献