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991.
Prehistoric cultivated cucurbits from the Viru Valley,Peru 总被引:1,自引:0,他引:1
A sample of 535 specimens of cucurbits were retrieved from archaeological deposits in the Viru Valley, Peru, from contexts dated between ca. 1800 B.C.– 1100 A.D. by Carbon-14 analysis and cultural associations. Cultivars ofCucurbita maxima Duch. and C.moschata (Duch.) Duch. ex Poir. are found to be restricted, respectively, to early and late chronological periods, with no overlap. Cultural and ecological factors are suggested to account for the observed temporal and spatial variations in species occurrence. Comparison of materials from other coastal valleys indicat es significant, but presently unexplainable, spatial and temporal differences in the distribution of these species. Supportive evidence for South America as an independent center of domestication for C.maxima tis offered. 相似文献
992.
The mobility of concanavalin A (ConA) receptors on the surfaces of mouse embryo cells are affected by cell-substratum interactions. When the cells are grown on a substratum from which they are easily detached by EDTA, their receptors have an increased mobility and are redistributed into patches after incubation with ConA at 37 °C. 相似文献
993.
Pulse-labeled oocyte proteins were found to have a maximum average half-life of 73 h. In general, larger peptides underwent degradation at a faster rate than smaller peptides. In this respect, oocytes are similar to most other cells. Microinjected 125I-labeled bovine serum albumin (BSA) was degraded over a 40 h period with a half-life of 20–30 h, regardless of the method of protein labeling, culture medium employed, size of oocyte microinjected, or hormonal history of the oocyte. The last two results, if applicable to oocyte proteins in general, imply that protein catabolism is constant throughout the later stages of oogenesis and that growth is primarily regulated by a stimulation of anabolism. Individual proteins microinjected into oocytes undergo rates of degradation consistent with turnover rates obtained in other systems. Sequestered 125I-labeled BSA is only partially (40%) degraded, which indicates that, unlike microinjected 125I-labeled BSA, it has access to a cytoplasmic compartment (yolk platelets?) within which it is relatively stable. 相似文献
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998.
Thomas W. Maretzki 《Culture, medicine and psychiatry》1979,3(1):95-110
The publication of Joseph Westermeyer, ed., Anthropology and Mental Health: Setting a New Course, is the departure point for taking stock of past and present links between anthropology and psychiatry. These reflections relate historical trends to the conference volume which contains examples of recent interdisciplinary research. The article critically reviews some of these and then suggests other recent or current work, not mentioned, which the author considers representative of some of the promising results of anthropological contributions to psychiatric interests. Questions are raised, but left unanswered, which might be further examined in attempts to continue long established interdisciplinary collaboration. 相似文献
999.
The results presented in this paper show that lysis of human erythrocytes by linoleic acid is not caused by peroxidation of
the fatty acid. Peroxidase, superoxide dismutase and scavengers of O
2
−
and OH had no effect on the lysis while catalase showed only marginal inhibition suggesting that O
2
−
, OH, O
2
−
and H2O2 do not play any direct role in hemolysis by linoleic acid. Generators of H2O2 inhibited the lysis completely and methemoglobin cells were more resistant to hemolysis by linoleic acid. The fatty acid
did neither bind to nor fomed complex with red cell ghosts. Membrane oxidation of sulphydryl groups was also not involved
in the lysis. Β-Carotene, retinol and bile salts enhanced the lysis, while, cholesterol but not cholesterol acetate, inhibited
it. Taurocholate-pretreated cells were more susceptible to linoleic acid lysis. These observations suggested-that lysis by
linoleic acid may be due to its detergent property. 相似文献
1000.
2-(5'-Phenylpentyl)fumaric acid was shown to be a competitive inhibitor (Ki 0.5 mM) of pig heart fumarase. After nitration of the aromatic ring, reduction to the amine and diazotization, the acid was attached via azo linkages to a Sepharose 4B-tyramine matrix. The resulting adsorbent was used for the affinity chromatography of crude fumarase, purifications of approx. 20-fold being obtained by specific elution with 0.01 M-citrate. 相似文献