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841.
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The feeding and attraction of Agelastica coerulea (Baly) to nine species of Betulaceae in four genera (Alnus, Betula, Carpinus, and Corylus) were examined in the laboratory by using choice and no-choice as well as olfactometer bioassays. In no-choice feeding bioassays with A. coerulea larvae, Alnus hirsuta (Spach) Ruprecht, Alnus japonica Steudel, Corylus sieboldiana variety mandshurica (Max.) c. k. Schneider, and Corylus heterophylla variety thunbergii Blume were the most preferred, whereas Betula davurica Pallas, Betula schmidtii Regel, and Carpinus cordata Blume were the least preferred. The larvae showed moderate preference for Alnus maximowiczii Callier and Carpinus tschonoskii variety brevicalycina Nakai. In choice feeding bioassays, no differences in preference between A. hirsuta and A. japonica were observed. However, there were significant differences in preference between A. hirsuta and each of the other seven plant species. In olfactometer bioassays with adult female A. coerulea, fresh leaf odor from A. hirsuta attracted significantly more adults than that from A. japonica and C. sieboldiana variety mandshurica. These results indicate that A. coerulea differed in its ability to discriminate among the Betulaceae plants at the feeding preference and attraction of host selection. 相似文献
844.
Pawar P Shin PK Mousa SA Ross JM Konstantopoulos K 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(2):1258-1265
The interaction between surface components on the invading pathogen and host cells such as platelets plays a key role in the regulation of endovascular infections. However, the mechanisms mediating Staphylococcus aureus binding to platelets under shear remain largely unknown. This study was designed to investigate the kinetics and molecular requirements of platelet-S. aureus interactions in bulk suspensions subjected to a uniform shear field. Hydrodynamic shear-induced collisions augment platelet-S. aureus binding, which is further potentiated by platelet activation with stromal derived factor-1beta. Peak adhesion efficiency occurs at low shear (100 s(-1)) and decreases with increasing shear. The molecular interaction of platelet alpha(IIb)beta(3) with bacterial clumping factor A through fibrinogen bridging is necessary for stable bacterial binding to activated platelets under shear. Although this pathway is sufficient at low shear (=400 s(-1)), the involvement of platelet gpIb and staphylococcal protein A through von Willebrand factor bridging is essential for optimal recruitment of S. aureus cells by platelets in the high shear regime. IgG plays an inhibitory role in the adhesion process, presumably by interfering with the binding of von Willebrand factor to staphylococcal protein A. This study demonstrates that platelet activation and a fluid-mechanical environment representative of the vasculature affect platelet-S. aureus cell-adhesive interactions pertinent to the process of S. aureus-induced bloodstream infections. 相似文献
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846.
Bending stiffness of a crystalline actin bundle 总被引:1,自引:0,他引:1
The acrosomal process of the sperm of the horseshoe crab (Limulus polyphemus) is a unique crystalline actin bundle, consisting of multiple actin filaments cross-linked by the actin-bundling protein, scruin. For successful fertilization, the acrosomal bundle must penetrate through a 30 microm thick jelly coat surrounding the egg and thus it must be sufficiently stiff. Here, we present two measurements of the bending stiffness of a single crystalline bundle of actin. Results from these measurements indicate that the actin:scruin composite bundle has an average elastic modulus of 2 GPa, which is similar to that of a single actin filament, and a bending stiffness that is more than two orders of magnitude larger than that of a bundle of uncross-linked actin filaments due to stiffening by the scruin matrix. 相似文献
847.
Park JH Guk SM Kim TY Shin EH Lin A Park JY Kim JL Hong ST Chai JY 《The Korean journal of parasitology》2004,42(1):41-44
The pond smelt Hypomesus olidus and minnow Zacco platypus were collected from the Soyang and Daechung Lakes in January 2003, and their metacercarial infections was examined by the muscle compression and artificial digestion techniques. In the Soyang Lake, 161 metacercariae of Clonorchis sinensis (0.35 per fish) were harvested from 459 pond smelts examined. Also, 13 metacercariae of C. sinensis (0.43 per fish), 1 of Metagonimus sp., 4 of Echinostoma sp., 148 of Centrocestus armatus and 44 unidentified species were collected from 30 minnows. In the Daechung Lake, 369 metacercariae of C. sinensis (3.69 per fish) and 51 unidentified species were recovered from 100 pond smelts. The metacercariae of C. sinensis were fed to experimental rats, in which the adult flukes were identified. The pond smelts and minnows collected from the Soyang and Daechung Lakes were verified to be the second intermediate hosts and the sources of human C. sinensis infection. 相似文献
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849.