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Tobacco leaves depleted of starch, were detached and allowedto assimilate equal amounts of 14CO2 and 12CO2in succession,and vice versa. Distribution of radioactivity in starch, andsugars was determined after assimilation and after disks cutfrom the leaves had been kept in darkness for times up to 40hours. The amount and activity of the CO2 was also determined.14C and 12C were incorporated in equal amounts into starch independentlyof the order in which they were supplied. In contrast sucrosehad high activity 14C was given last, and hexose a low one.The reverse was true when 12C was given last. Activity of respiratoryCO2 was slightly higher when 14C was assimilated last as comparedwith 12C. In the dark only 14C or 12C was at first lost fromstarch, in accordance or removal of discrete layers. Analyticalresults show that starch is the main respiratory substrate andto account for the redistribution of radioactivity in passageto CO2 it is concluded that sucrose occurs at two sites separatedinter-or intra-cellularly, one of which is in equilibrium withthe system intrconverting starch and CO2 and at the other hexosesare produced by inversion. A starch-like polysaccharide is formedduring assimilation which persists in the dark and there isa significant contribution to respiration of carbon from non-carbohydratesources when leaf disks are kept on the dark. 相似文献
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ELIANA M. M. ROCHA MICHAEL R. HOLLINGDALE BARBARA SINA PAMELA LELAND JOSÉ D. LOPES ANTONIANA U. KRETTLI 《The Journal of eukaryotic microbiology》1993,40(1):61-63
ABSTRACT. Monoclonal antibodies that react with the circumsporozoite protein of the avian malaria Plasmodium gallinaceum sporozoites also reacted with circumsporozoite protein of the rodent malaria Plasmodium berghei. Two types of reactivity were identified: 1) two monoclonal antibodies reacted with P. berghei sporozoite protein by enzyme-linked immunosorbent assay, Western blot and indirect immunofluorescence antibody, 2) six other monoclonal antibodies reacted with P. berghei sporozoites by ELISA and Western blot only. We studied whether these differences could be explained by reactivity in enzyme-linked immunosorbent assay with different P. berghei circumsporozoite peptides. Although all P. gallinaceum monoclonal antibodies reacted with the P. berghei repeats, the first group reacted with a conserved peptide sequence, N1, whereas the second group did not. These results suggest that circumsporozoite proteins from P. gallinaceum and P. berghei share common epitopes. the biological significance of our finding is not yet clear. Indeed, the cross-reactive monoclonal antibodies giving a positive indirect immunofluorescence antibody with the P. berghei sporozoites only caused a borderline effect on the living P. berghei parasites in vitro as measured by inhibition of sporozoite infectivity. 相似文献
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FITZ JOHN PORTER POOLE 《The Australian journal of anthropology》1984,14(3):191-216
The Bimin-Kuskusmin of the West Sepik interior of Papua New Guinea elaborate a complex folk theory of procreation that becomes the ‘natural’ foundation of some ideologically significant constructions of the individual, the person, gender, and societal continuity. Drawing on certain aspects of Weiner's model of reproduction and regeneration, symbols of substance and insubstantial ‘spirit’ that form this ‘natural’ foundation of the Bimin-Kuskusmin ideology of birth, death, and rebirth are explored in contexts of rites of passage that mark the course of the life-cycle from conception to death and ancestorhood. The key symbols of this cultural ideology are the enduring substances of bone, bone marrow, and finiik spirit, which are the basis of reckoning the cyclical regeneration of clan categories. 相似文献