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Brain Cell Biology - The previously described unilateral condensation of axoplasmic organelles at the node of Ranvier of large diameter fibres in spinal nerve roots has been confirmed in a single... 相似文献
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Nicholas P.C. Horrocks Fritz Vollrath Cedric Dicko 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2013,164(4):645-652
To better understand how silkmoth cocoons maintain the correct internal moisture levels for successful pupation, we examined cocoons from the long-domesticated mulberry silkmoth Bombyx mori as well as from two wild silkmoth species, Antheraea pernyi and Philosamia cynthia ricini. We determined fluid-independent values for the porosity, tortuosity and permeability of the inner and outer surfaces of cocoons. Permeabilities were low and, with the exception of A. pernyi cocoons, inner surfaces were less permeable than outer surfaces. B. mori cocoons exhibited the highest permeability overall, but only at the outer surface, while A. pernyi cocoons appeared to show different patterns from the other species tested. We discuss our findings in light of the ecophysiology of the various species and propose a ‘tortuous path’ model to help explain our results. The model describes how the structure of the inner and outer layers of the cocoon allows it to function as both a humidity trap and a waterproof barrier, providing optimum conditions for the successful development of the pupa. 相似文献
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Stefano Benvegnù Diego Franciotta Josh Sussman Angela Bachi Elisabetta Zardini Paola Torreri Cedric Govaerts Salvatore Pizzo Giuseppe Legname 《PloS one》2009,4(6)
Doppel protein (Dpl) is a paralog of the cellular form of the prion protein (PrPC), together sharing common structural and biochemical properties. Unlike PrPC, which is abundantly expressed throughout the central nervous system (CNS), Dpl protein expression is not detectable in the CNS. Interestingly, its ectopic expression in the brain elicits neurodegeneration in transgenic mice. Here, by combining native isoelectric focusing plus non-denaturing polyacrylamide gel electrophoresis and mass spectrometry analysis, we identified two Dpl binding partners: rat alpha-1-inhibitor-3 (α1I3) and, by sequence homology, alpha-2-macroglobulin (α2M), two known plasma metalloproteinase inhibitors. Biochemical investigations excluded the direct interaction of PrPC with either α1I3 or α2M. Nevertheless, enzyme-linked immunosorbent assays and surface plasmon resonance experiments revealed a high affinity binding occurring between PrPC and Dpl. In light of these findings, we suggest a mechanism for Dpl-induced neurodegeneration in mice expressing Dpl ectopically in the brain, linked to a withdrawal of natural inhibitors of metalloproteinase such as α2M. Interestingly, α2M has been proven to be a susceptibility factor in Alzheimer''s disease, and as our findings imply, it may also play a relevant role in other neurodegenerative disorders, including prion diseases. 相似文献