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781.
A study was made of different treatments for the inactivation of St. Louis encephalitis virus in smears prepared for immunofluorescence microscopy. Treatment of infected cells with 0.3% betapropiolactone at 56 degrees C for 40 min resulted in an inactivated virus suitable for immunofluorescence studies. 相似文献
782.
Christian Peter Klingenberg Rosalind H. Barrington Leigh B. Andrew Keddie John R. Spence 《Ecography》1997,20(1):29-36
Water striders harbor a diverse assemblage of symbionts in their digestive tract We used a field experiment, in which water striders were reared in enclosures in their natural pond habitat, to assess the effects of gut symbionts on growth Trypanosomatid flagellates had significant adverse effects on both development time and adult size, and therefore are clearly parasitic Yet because of their low prevalences (2% or less), trypanosomatids cannot be a major factor in the dynamics of our study population Gregannes occurred in 36% of the water striders, often in high numbers, and filling the entire midgut of some bugs Nevertheless, infected and uninfected gerrids did not differ in their growth, and gregarine loads were uncorrelated with development time and adult size attained We also did not find effects of gregarines in a second experiment with different rearing conditions, including a treatment with food stress We used a quantitative genetic approach to test if resistance against gregarines has a heritable component There was no evidence for any genetic variation, suggesting that variability in gregarine loads is the result of environmental heterogeneity Comparison with published reports from water striders shows that there is a great variability in the diversity and prevalence of symbionts among different populations and species, of gerrids 相似文献
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E J Mylecharane I Spence R P Gregson 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1984,79(2):395-399
The effects of atraxin, a neurotoxic protein from the venom glands of the funnel-web spider (Atrax robustus), have been studied in anaesthetized monkeys. At doses of 70 and 80 micrograms kg-1 i.v., atraxin caused respiratory disturbances (dyspnoea and apnoea), and profound alterations in heart rate and blood pressure. These doses also caused salivation, lachrymation, skeletal muscle fasciculation and an elevation in body temperature. Concurrent increases in firing were recorded from the phrenic nerve and from respiratory and other skeletal muscles. It is concluded that atraxin produces the same syndrome in primates as that observed with whole milked male funnel-web venom. 相似文献
790.
Biodistribution of the radioprotective drug 35S-labeled 3-amino-2-hydroxypropyl phosphorothioate (WR77913) 总被引:1,自引:0,他引:1
3-Amino-2-hydroxypropyl phosphorothioate (WR77913), a less toxic phosphorothioate radioprotector than WR2721, has been labeled with 35S. The biodistribution of a radioprotective dose of 800 mg/kg was determined in C3H mice bearing RIF-1 tumors as a function of time after intraperitoneal injection and was expressed as percentage injected dose/gram (% ID/g). Levels of 35S in the blood peaked 10 min after injection, and radioactivity in most tissues was highest at 15 min. Label in most tissues declined markedly between 15 and 60 min, but in gut, salivary glands, tumor, and brain, the levels of radioactivity remained quite stable over 1 hr. At 30 min after injection the highest levels of labeled drug were found in submandibular salivary glands, gut, and kidney, with the lowest level in brain. Tumors had approximately the same amount of label as blood, muscle, skin, and esophagus. Two principal differences between the distribution of label from WR77913 and WR2721 were defined. Although blood levels of 35S-WR2721 also peaked 10 min after injection, the 10-min blood levels achieved for WR77913 were more than fourfold greater than those attained by WR2721. Maximum levels of WR2721 occurred in most tissues 30 to 60 min after administration of the drug, compared to 15 min for WR77913. The basis for these differences remains to be determined, but these results suggest that the optimum interval between administration of WR77913 and irradiation may be shorter than for WR2721. 相似文献