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81.
Freshly prepared protoplasts of Saccharomyces cerevisiae X 2180 incorporate [3H]mannose and [14C]glucose for about 30 min into glycolipids and mannoproteins. Among the radioactive glycolipids formed dolichyl phosphate mannose, dolichyl phosphate glucose and dolichyl pyrophosphate oligosaccharides have been identified. The oligosaccharides released by weak acid from the dolichyl pyrophosphate were treated with endo-N-acetylglucosaminidase H and separated by gel filtration on Bio-Gel P-4. The largest oligosaccharide obtained corresponded exactly in size to Glc3Man9GlcNAc1 the compound formed also in animal tissues. Other oligosaccharides released from dolichyl pyrophosphate in addition to the glucose containing ones were mainly Man9GlcNAc1 and Man8GlcNAc1. No mannosyl oligosaccharide corresponding in size to the total inner core region found in native mannoproteins could be detected in a lipid-bound form.The radioactive dolichyl pyrophosphate oligosaccharides were formed transiently; after 40 min only about 40% of the maximal radioactivity was observed in this fraction. In the presence of cycloheximide this decrease did not take place.It is concluded that the dolichol pathway of N-glycosylation of glycoproteins in yeast cells is very similar, if not identical, to the reaction sequence worked out for animal cells.Dedicated to Professor Dr. Otto Kandler on his 60th birthday 相似文献
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Summary A main yolk component in the oocytes of the pulmonate snailPlanorbarius corneus L. has been isolated and identified as the iron storage protein ferritin by its ultrastructure, iron content, immuunological properties and behaviour in disc electrophoresis. As judged from acrylamide electrophoresis data and ultrastructural observations, yolk ferritin is an exogenous protein which is synthesised in the hepatopancreas and taken up by the oocytes by endocytosis. 相似文献
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Relationship between the chromatoid body and the acrosomal system in early spermatids of Myxine glutinosa L. 总被引:1,自引:0,他引:1
Summary A transient close relationship between the chromatoid body and the developing acrosome is demonstrated in early spermatids of Myxine glutinosa.This work was supported by the Norwegian Research Council for Science and Humanities (NAVF, Grant Nr. D 61.44) and the Austrian Fonds zur Förderung der wissenschaftlichen Forschung, Projekt 2183 相似文献
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87.
The conformation of two fragments derived from anti-poly(D-alanyl) antibodies, the divalent fragment (Fab')2 and the monovalent fragment Fab', was studied by small-angle X-ray scattering before and after interaction with the tetra-D-alanine amide hapten. More than 90% of the combining sites were occupied by the hapten. No significant changes were observed in the volume or in the radius of gyration, with either of the fragments. This contrasts with the significant decrease in these two parameters found upon reacting the hapten with intact anti-poly(D-alanyl) antibodies (I. Pilz, O. Kratky, A. Licht, and M. Sela (1973), Biochemistry 12, 4998). For Fab', the radius of the whole particle was found to be 3.48 nm in the absence of the hapten and 3.46 nm in its presence, the radius of gyration of the cross-section was 1.37 nm without hapten and 1.38 nm in its presence, and the volume of the particle was 98 nm3 in the absence of the hapten and 91 nm3 in its presence. For (Fab')2 the respective values were 5.06 and 5.05, 1.38 and 1.37, and 182 and 182. These results suggest that a conformational change occurs within the antibody molecule, but not within its Fab fragment, upon reaction with the tetraalanine hapten. 相似文献
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Ingrid S. Garcia Susana A. Teixeira Karine A. Costa Daniele B. D. Marques Gustavo de A. Rodrigues Thaís C. Costa Jos D. Guimares Pamela I. Otto Alysson Saraiva Adriana M. G. Ibelli Maurício E. Canto Haniel C. de Oliveira Mnica C. Ledur Jane de O. Peixoto Simone E. F. Guimares 《Molecular reproduction and development》2020,87(7):819-834
90.
Ingrid M. Lubbers Matty P. Berg Gerlinde B. De Deyn Wim H. van der Putten Jan Willem van Groenigen 《Global Change Biology》2020,26(3):1886-1898
Soil faunal activity can be a major control of greenhouse gas (GHG) emissions from soil. Effects of single faunal species, genera or families have been investigated, but it is unknown how soil fauna diversity may influence emissions of both carbon dioxide (CO2, end product of decomposition of organic matter) and nitrous oxide (N2O, an intermediate product of N transformation processes, in particular denitrification). Here, we studied how CO2 and N2O emissions are affected by species and species mixtures of up to eight species of detritivorous/fungivorous soil fauna from four different taxonomic groups (earthworms, potworms, mites, springtails) using a microcosm set‐up. We found that higher species richness and increased functional dissimilarity of species mixtures led to increased faunal‐induced CO2 emission (up to 10%), but decreased N2O emission (up to 62%). Large ecosystem engineers such as earthworms were key drivers of both CO2 and N2O emissions. Interestingly, increased biodiversity of other soil fauna in the presence of earthworms decreased faunal‐induced N2O emission despite enhanced C cycling. We conclude that higher soil fauna functional diversity enhanced the intensity of belowground processes, leading to more complete litter decomposition and increased CO2 emission, but concurrently also resulting in more complete denitrification and reduced N2O emission. Our results suggest that increased soil fauna species diversity has the potential to mitigate emissions of N2O from soil ecosystems. Given the loss of soil biodiversity in managed soils, our findings call for adoption of management practices that enhance soil biodiversity and stimulate a functionally diverse faunal community to reduce N2O emissions from managed soils. 相似文献