排序方式: 共有56条查询结果,搜索用时 15 毫秒
21.
22.
Barley aleurone cells contain two types of vacuoles. Characterization Of lytic organelles by use of fluorescent probes 总被引:10,自引:1,他引:9 下载免费PDF全文
Light microscopy was used to study the structure and function of vacuoles in living protoplasts of barley (Hordeum vulgare cv Himalaya) aleurone. Light microscopy showed that aleurone protoplasts contain two distinct types of vacuole: the protein storage vacuole and a lysosome-like organelle, which we have called the secondary vacuole. Fluorescence microscopy using pH-sensitive fluorescent probes and a fluorogenic substrate for cysteine proteases showed that both protein storage vacuoles and secondary vacuoles are acidic, lytic organelles. Ratio imaging showed that the pH of secondary vacuoles was lower in aleurone protoplasts incubated in gibberellic acid than in those incubated in abscisic acid. Uptake of fluorescent probes into intact, isolated protein storage vacuoles and secondary vacuoles required ATP and occurred via at least two types of vanadate-sensitive, ATP-dependent tonoplast transporters. One transporter catalyzed the accumulation of glutathione-conjugated probes, and another transported probes not conjugated to glutathione. 相似文献
23.
Nicholas PC Horrocks 《Ostrich》2016,87(1):95-97
I report an instance of usurpation of a Crowned Lapwing Vanellus coronatus nest by a pair of African Wattled Lapwings Vanellus senegalensis. The nest, which originally contained a single Crowned Lapwing egg, eventually contained an additional three Wattled Lapwing eggs, before it was predated. Although parents of both species were observed in the vicinity of the nest, video monitoring showed that the Wattled Lapwings incubated all four eggs. Detection of embryonic heart rate suggested that all the eggs were probably viable up until the nest was destroyed. Nest usurpation in shorebirds is rare, and given the easily accommodated nest requirements and minimal costs of nest construction in these species, is difficult to explain. I speculate that the occurrence described here may represent a case of mistaken identity by the female Wattled Lapwing when choosing a nest scrape, since there seems to have been little benefit to the usurping species of taking over an already occupied nest. 相似文献
24.
Jean Cury Thomas Jové Marie Touchon Bertrand Néron Eduardo PC Rocha 《Nucleic acids research》2016,44(10):4539-4550
Integrons recombine gene arrays and favor the spread of antibiotic resistance. Their broader roles in bacterial adaptation remain mysterious, partly due to lack of computational tools. We made a program – IntegronFinder – to identify integrons with high accuracy and sensitivity. IntegronFinder is available as a standalone program and as a web application. It searches for attC sites using covariance models, for integron-integrases using HMM profiles, and for other features (promoters, attI site) using pattern matching. We searched for integrons, integron-integrases lacking attC sites, and clusters of attC sites lacking a neighboring integron-integrase in bacterial genomes. All these elements are especially frequent in genomes of intermediate size. They are missing in some key phyla, such as α-Proteobacteria, which might reflect selection against cell lineages that acquire integrons. The similarity between attC sites is proportional to the number of cassettes in the integron, and is particularly low in clusters of attC sites lacking integron-integrases. The latter are unexpectedly abundant in genomes lacking integron-integrases or their remains, and have a large novel pool of cassettes lacking homologs in the databases. They might represent an evolutionary step between the acquisition of genes within integrons and their stabilization in the new genome. 相似文献
25.
26.
27.
Determinants of participation restriction among community dwelling stroke survivors: A path analysis
Background
Apart from promoting physical recovery and assisting in activities of daily living, a major challenge in stroke rehabilitation is to minimize psychosocial morbidity and to promote the reintegration of stroke survivors into their family and community. The identification of key factors influencing long-term outcome are essential in developing more effective rehabilitation measures for reducing stroke-related morbidity. The aim of this study was to test a theoretical model of predictors of participation restriction which included the direct and indirect effects between psychosocial outcomes, physical outcome, and socio-demographic variables at 12 months after stroke. 相似文献28.
A sample of fixed bacterial cells was examined by immunofluorescence microscopy using an Alexa 488 conjugated secondary antibody for visualization. Excitation using visible light confirmed the expected photostability of this fluorophore; however, when using 2-photon excitation, Alexa 488 was rapidly and substantially photobleached. The unexpected instability of Alexa 488 under certain conditions may have deleterious consequences if not anticipated and accommodated in experimental protocols. 相似文献
29.
Receptor tyrosine kinases (RTKs) are key components of cell–cell signalling required for growth and development of multicellular
organisms. It is therefore likely that the divergence of RTKs and associated components played a significant role in the evolution
of multicellular organisms. We have carried out the present study in hydra, a diploblast, to investigate the divergence of
RTKs after parazoa and before emergence of triploblast phyla. The domain-based screening using Hidden Markov Models (HMMs)
for RTKs in Genomescan predicted gene models of the Hydra magnipapillata genome resulted in identification of 15 RTKs. These RTKs have been classified into eight families based on domain architecture
and homology. Only 5 of these RTKs have been previously reported and a few of these have been partially characterized. A phylogeny-based
analysis of these predicted RTKs revealed that seven subtype duplications occurred between ‘parazoan–eumetazoan split’ and
‘diploblast–triploblast split’ in animal phyla. These results suggest that most of the RTKs evolved before the radiata–bilateria
divergence during animal evolution. 相似文献
30.
De Rooy DP Willemze A Mertens B Huizinga TW Van der Helm-van Mil AH 《Arthritis research & therapy》2011,13(5):R180