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621.
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Eight-to-10-wk-old offspring of a colony of specific pathogen free [Eda:(NZW x FG)F1BR] rabbits were exposed to cultures of Pasteurella multocida and Bordetella bronchiseptica. Two groups of 9 animals each were exposed to cultures of either species of bacteria intranasally and killed 2, 7, 14, and 21 da postinoculation. Five of 9 rabbits in each group developed a mucopurulent nasal discharge 4-7 da postinoculation. The remaining 4 rabbits in each group failed to develop clinical signs. The gross and microscopic lesions did not differ in character or distribution among the inoculated rabbits. The infection was characterized by an acute upper respiratory syndrome accompanied by a mild bronchopneumonia. 相似文献
623.
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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Jessica N. Witchley Pauline Basso Cedric A. Brimacombe Nina V. Abon Suzanne M. Noble 《Cell host & microbe》2021,29(6):1002-1013.e9
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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
629.
Ambient temperature and sound power of cicada calling songs (Hemiptera: Cicadidae: Tibicina) 总被引:1,自引:1,他引:0
Abstract. Male cicadas produce a loud calling song that attracts females at long range. In some cases, ambient temperature has been shown to have an effect on the temporal structure of this acoustic signal. Here, a positive correlation is reported for the first time between the ambient temperature and the sound power of the calling song. This relationship is illustrated in three species of the Palaearctic genus Tibicina : Tibicina corsica fairmairei Boulard, Tibicina garricola Boulard and Tibicina tomentosa Olivier. It is suggested that the males thermoregulate behaviourally. The minimal ambient temperature range that the Tibicina species need to call is 22–24 °C. The effect of ambient temperature on calling song power is assumed to be the result of thermal effects in the response of the acoustic system (i.e. muscle activity of the acoustic system being temperature-dependent). Inter-individual and interspecific differences in calling song power are interpreted in the general context of the Tibicina sound behaviour. 相似文献
630.
Malaria remains the single largest threat to child survival in sub-Saharan Africa and warrants long-term investment for control. Previous malaria distribution maps have been vague and arbitrary. Marlies Craig, Bob Snow and David le Sueur here describe a simple numerical approach to defining distribution of malaria transmission, based upon biological constraints of climate on parasite and vector development. The model compared well with contemporary field data and historical 'expert opinion' maps, excepting small-scale ecological anomalies. The model provides a numerical basis for further refinement and prediction of the impact of climate change on transmission. Together with population, morbidity and mortality data, the model provides a fundamental tool for strategic control of malaria. 相似文献