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171.
Guaraná (Paullinia cupana) is a woody vine or sprawling shrub native to the central Amazon Basin. The seeds are commercially produced on some 6,000 ha in the state of Amazonas near Manaus. The principal article of commerce is an amber-colored, carbonated soft drink. It is also widely used as a high caffeine stimulant and in local medicines. The plant is monoecious and is damaged by a number of diseases, the most severe being anthracnose. Prospects are excellent for greatly expanded international markets. 相似文献
172.
J Ignacio Andrés Jesús Alcázar José M Alonso Adolfo Díaz Javier Fernández Pilar Gil Laura Iturrino Encarna Matesanz Theo F Meert Anton Megens Victor K Sipido 《Bioorganic & medicinal chemistry letters》2002,12(2):249-253
Following the programme started at Janssen Research Foundation searching for 5-HT(2A/2C) antagonists, we now report on the synthesis of a series of substituted 2-(Dimethylaminomethyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives. The 5-HT(2A), 5-HT(2C) and H(1) receptor affinities as well as the mCPP antagonistic activity of the compounds synthesised is described. 相似文献
173.
174.
175.
C. van Leeuwen 《Biotechnology and bioengineering》1979,21(11):2125-2131
The determination of the overall volumetric mass-transfer coefficient with the dynamic measurement technique involves modeling, parameter estimation, and experimental design. The combination and extension of previous efforts lead to some suggestions for improvements. 相似文献
176.
A. Cohen A. M. Breure D. J. M. Schmedding R. J. Zoetemeyer J. G. van Andel 《Applied microbiology and biotechnology》1985,21(6):404-408
Summary The effect of partial pre-acidification of carbohydrate containing wastewaters on anaerobic digester performance was investigated. The influent was a 1% (w/v) glucose solution in a mineral salts medium imposing carbon-limited growth conditions. Up to 13% of the Chemical Oxygen Demand (COD) was added as volatile fatty acids (VFA).In all cases, addition of VFA to the glucose medium resulted in significant increases in the maximum specific COD-conversion rates of the sludge (both with respect to continuous feeding and following a shock loading), as compared with values found on digestion of glucose media alone. 相似文献
177.
We compared changes in body condition (relative weight) and mercury concentrations ([Hg]) in two species of coregonid fish (lake herring Coregonus artedi, lake whitefish C. clupeaformis) among discrete populations in Ontario between 1967 and 2006. Temporal comparisons among populations were made to determine whether 1) the establishment of Bythotrephes longimanus had affected coregonid populations, or 2) if changes in body condition or [Hg] were related to regional differences in the degree of climate change during the time period investigated. Climate data from northwestern, northeastern and southern Ontario showed a general warming trend in all regions over the period of study. However, greater temporal changes in climate were observed in the northwest where growing degree days >5°C (GDD) increased and precipitation declined over the study period compared with relatively little change in southern or northeastern Ontario. Correspondingly, northwestern Ontario coregonid populations demonstrated significantly greater declines in body condition relative to those from northeastern or southern Ontario. Declines in [Hg] of both species were also greater among northwestern populations compared with those from northeastern or southern Ontario but only significantly so for lake herring. These declines were independent of the invasion of non‐native Bythotrephes, and declines in [Hg] were opposite predictions based on the hypothesis that Bythotrephes invasion lengthened aquatic food chains. Based on our findings and further evidence from the literature, we propose that warming regional climates are capable of contributing to declines in both condition and [Hg] of fishes. Because fish condition affects both reproductive success and overwinter survival, observed condition declines of the magnitude reported here could have profound implications for the structure of future aquatic ecosystems in a warming climate. 相似文献
178.
Inducible DNA polymerase I synthesis in a UV hyper-resistant mutant of Escherichia coli 总被引:1,自引:0,他引:1
A mutant of Escherichia coli which is more resistant to shortwave UV light than its wild-type parent strain and which can synthesise DNA polymerase I constitutively has been further analysed. It carries two mutational alleles which are located about 1.5 min apart and cotransducible by P1 with the argH locus. The two mutational alleles have been segregated and their analysis shows that one of them is responsible for UV hyper-resistance whereas the other mutation confers UV sensitivity. Recombinant plasmids carrying various sections of the polA regulatory region, linked to a galK gene, were introduced into the mutant strains. Analysis of galactokinase shows that the enzyme activity in the UV hyper-resistant mutant is increased. The results suggest that the synthesis of DNA polymerase I in E. coli is inducible. 相似文献
179.
Bilateral electrolytic lesions restricted to the lateral, basolateral and basomedial amygdaloid nuclei in mice produced a lack of avoidance responses towards novel stimuli. While controls showed avoidance and burying reactions to a novel object introduced into their familiar environment, lesioned mice displayed a high number of approach responses and a low level of burying reactions. Furthermore, when given the opportunity to move around freely in simultaneously presented novel and familiar places, control mice at first exhibited avoidance reactions to the novel environment before showing novelty preference. There were no avoidance reactions in lesioned mice. These data are consistent with the hypothesis that amygdala plays a specific role in the regulation of defensive reactions. 相似文献
180.
Iodination of the exposed Tyr-25 in the coat protein decreases the fluorescence intensity of the filamentous phage Pf1 to less than 3% of its original fluorescence. If one assumes that the total residual fluorescence originates from the non-iodinated, buried Tyr-40, one can estimate the distance between Tyr-40 and the DNA bases in Pf1 to be less than 7 A, making use of the Foerster law for fluorescence energy transfer. The result is consistent with the idea that Tyr-40-DNA interaction is responsible for the unusually large axial base separation in Pf1-DNA. 相似文献