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151.
To broaden the range of tools available for proteomic research, we generated a library of 16,368 unique full-length human ORFs that are expressible as N-terminal GST-His(6) fusion proteins. Following expression in yeast, these proteins were then individually purified and used to construct a human proteome microarray. To demonstrate the usefulness of this reagent, we developed a streamlined strategy for the production of monospecific monoclonal antibodies that used immunization with live human cells and microarray-based analysis of antibody specificity as its central components. We showed that microarray-based analysis of antibody specificity can be performed efficiently using a two-dimensional pooling strategy. We also demonstrated that our immunization and selection strategies result in a large fraction of monospecific monoclonal antibodies that are both immunoblot and immunoprecipitation grade. Our data indicate that the pipeline provides a robust platform for the generation of monoclonal antibodies of exceptional specificity.  相似文献   
152.
No commercially live vaccine against cholera caused by Vibrio cholerae O139 serogroup is available and it is currently needed. Virulent O139 strain CRC266 was genetically modified by firstly deleting multiple copies of the filamentous phage CTXφ, further tagging by insertion of the endoglucanase A coding gene from Clostridium thermocellum into the hemagglutinin/protease gene and finally deleting the mshA gene, just to improve the vaccine biosafety. One of the derived strains designated as TLP01 showed full attenuation and good colonizing capacity in the infant mouse cholera model, as well as highly immunogenic properties in the adult rabbit and rat models. Since TLP01 lacks MSHA fimbriae, it is refractory to infection with another filamentous phage VGJφ and therefore protected of acquiring CTXφ from a recombinant hybrid VGJφ/CTXφ. This strategy could reduce the possibilities of stable reversion to virulence out of the human gut. Furthermore, this vaccine strain was impaired to produce biofilms under certain culture conditions, which might have implications for the strain survival in natural settings contributing to vaccine biosafety as well. The above results has encouraged us to consider TLP01 as a live attenuated vaccine strain having an adequate performance in animal models, in terms of attenuation and immunogenicity, so that it fulfills the requirements to be evaluated in human volunteers.  相似文献   
153.
Aim The global richness gradient of angiosperm families is correlated with current climate, and it has been claimed that historical processes are not necessary to understand patterns of plant family richness. This claim has drawn criticism, and there have been doubts about the quality of the data used to quantify the pattern. We revisit this issue using the Angiosperm Phylogeny Group (APG) III classification and revised range maps, and we incorporate an evolutionary variable, family age, to explore covariation between evolution and ecology and their links to climate via the tropical conservatism hypothesis (TCH). Location Global. Methods The richness pattern for 408 families was derived from range maps, and family ages were derived from a dated angiosperm phylogeny. Patterns were generated for all families, 143 families composed of trees, and 149 families composed of herbs. We also examined family range size patterns to test the extent to which extratropical floras are nested subsets of tropical floras. Ordinary least squares (OLS) multiple and partial regressions were used to generate climate models for richness, mean range size and mean age for each plant dataset and to evaluate the covariation between contemporary climate and clade age as correlates of family richness. Results We confirmed the strong association between contemporary climate and family richness. Age patterns predicted by TCH were also found for families comprising trees. The richness of herbaceous families, in contrast, was correlated with climate but the age pattern was not as predicted by TCH. Floras in cold and dry areas are strongly nested within richer tropical floras. Main conclusions Phylogenetic niche conservatism at the family level offers a likely explanation for the global diversity gradient of trees, but not for non‐desert herbs, probably because of the faster evolutionary rates for herbs and less constrained evolutionary responses to climate change. Thus, it appears that multiple processes account for the overall angiosperm family gradient. Our analysis also demonstrates that even very strong associations of taxon richness and climate do not preclude evolutionary processes, as has been widely argued, and that climatic and evolutionary hypotheses for richness gradients are not mutually exclusive.  相似文献   
154.
155.
Summary High resolution thermal denaturation profiles of different members of fungus genus Fusarium were compared with respect to the shape of their DNA melting curves. Quantitative comparison of the shape (areas under differential curves) of all thermal denaturation profiles was made. Thermal denaturation profiles can be used to derive the quantitative parameter, genetic distance, defined by Soumpasis (12). Based on such data of genetic distance a dendrogram and a genetic distance tree was constructed.  相似文献   
156.
Exogenous ATP induces inward currents and causes the release of arginine-vasopressin (AVP) from isolated neurohypophysial terminals (NHT); both effects are inhibited by the P2X2 and P2X3 antagonists, suramin and PPADS. Here we examined the role of endogenous ATP in the neurohypophysis. Stimulation of NHT caused the release of both AVP and ATP. ATP induced a potentiation in the stimulated release of AVP, but not of oxytocin (OT), which was blocked by the presence of suramin. In loose-patch clamp recordings, from intact neurohypophyses, suramin or PPADS produces an inhibition of action potential currents in a static bath, that can be mimicked by a hyperpolarization of the resting membrane potential (RMP). Correspondingly, in a static versus perfused bath there is a depolarization of the RMP of NHT, which was reduced by either suramin or PPADS. We measured an accumulation of ATP (3.7 +/- 0.7 microM) released from NHT in a static bath. Applications of either suramin or PPADS to a static bath decreased burst-stimulated capacitance increases in NHT. Finally, only vasopressin release from electrically stimulated intact neurohypophyses was reduced in the presence of Suramin or PPADS. These data suggest that there was sufficient accumulation of ATP released from the neurohypophysis during stimulations to depolarize its nerve terminals. This would occur via the opening of P2X2 and P2X3 receptors, inducing an influx of Ca2+. The subsequent elevation in [Ca2+](i) would further increase the stimulated release of only vasopressin from NHT terminals. Such purinergic feedback mechanisms could be physiologically important at most CNS synapses.  相似文献   
157.
Early arable activity in Iceland, introduced in the late ninth century A.D., has been characterized as marginal and at a subsistence level, largely abandoned by the 1500s as a result of climatic deterioration. This view has been advanced without considering soils data, the medium in which crops are grown and in which evidence of early land management is retained. Soil thin section micromorphology together with soil total phosphorus values are used to assess land manuring and cultivation strategies at two sites in south-west Iceland, where place name and palynological evidence indicate that arable activity has taken place. Agro-ecosystem modeling, using the CENTURY model, is undertaken to predict grain yields at these sites, and to assess the significance of soil properties and soil management in determining yields. The results of these analyses demonstrate that manure application rates were low, and support the view that grain yields were at a subsistence level. The results also suggest soils, and the management of soils, rather than climate was the major limitation to arable production. Shortages of both available manure and labor are suggested as barriers to soils and grain productivity improvements in early Iceland. The paper highlights the need to include soils analyses in discussions of early agricultural economies.  相似文献   
158.
Seed germination percentage and rate of Rubia fruticosa, an endemic Macaronesian shrub was assessed with seed lots collected at three levels of an altitudinal gradient (200–800 m asl) located in El Hierro Island (Canarian Archipelago). Both seeds collected from control plants and those found in lizard droppings were studied. A significant decrease in the germination percentage was observed with control seeds and those seeds which are previously eaten by lizards if collected at 800 m asl. This indicates that R. fruticosa is a plant whose optimal germination environment is located between 200 and 500 m asl, occurring in higher altitudes only under sub-optimal conditions. The effect of lizard gut on R. fruticosa seeds was variable in the two study years: while germination percentage of seeds having passed through the lizards was not significantly different to that of control seeds in the first year, an increased germination was found for the animal-treated seeds in all three altitudinal zones in the second year. In general, germination rate of control seeds was rather variable between years. However, improvement of R. fruticosa seed germination caused by lizards may be important for its fitness; and a co-evolution may have occurred, since lizards and seeds of this endemic plant have been intensively interacting for millions of years in the lower zones of the Canary Islands.  相似文献   
159.
Aposematic signals represent one of the classical systems to study evolution and, as such, they have received considerable empirical and theoretical investigation. Despite the extensive literature on aposematic coloration, much uncertainty remains about genetic changes responsible for the repeated evolution of similar signals in multiple lineages. Here, we study the diversification and convergence of coloration among lineages of aposematic harlequin poison frogs (Oophaga histrionica complex). Our results suggest that different background phenotypes, showing different color and/or luminance contrast, have evolved independently at least twice in this group. We suggest that cellular arrangements are behind the striking diversity of color and patterns in this group and propose that differences in dorsal background color may be related to either or both, the presence/absence of xanthophores and the dispersion of melanosomes. Our genetic analyses support a role for the melanocortin receptor MC1R in melanosome aggregation, and we show evidence that two different mutations (?433 and C432A) are responsible for the darker phenotypes that may display a more detectable, easier to learn, aposematic signal.  相似文献   
160.
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