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A mutagenicity study was carried out in mice fed on a gamma-irradiated diet. As an indicator of mutagenic activity, we observed an incidence of micronuclei in erythrocytes. The average body weight of the mice fed on the diet irradiated to dose range of 400-1,000 kGy decreased, and the mice fed on the 800-1,000 kGy-irradiated diet died during the period from 8 to 14 days after the start of feeding. On the other hand, when the mutagenic activity of the irradiated diet was tested by observing occurrence of micronucleus in erythrocytes, no significant increase was recognized. These results indicated that the irradiated diet had no mutagenic activity, even though it possessed a toxic effect on the growth of mice. 相似文献
85.
I Takashima N Hashimoto T Watanabe L Rosen 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(5):947-953
A study was conducted during 1985 and 1986 to evaluate the roles of mosquito species as possible vectors of Japanese encephalitis (JE) virus in Hokkaido. The number of Culex tritaeniorhynchus was very low among the four pig farms where outbreaks of abortion caused by JE virus were observed in swine populations. At one farm near Sapporo, only one Cx. tritaeniorhynchus was found among a total of 510 mosquitoes collected during the survey period from July to October 1985, even when JE virus activity among sentinel pigs was revealed by seroconversion. At another farm in the south, no individuals of this mosquito species were found among 987 mosquitoes collected at the time of the outbreaks of abortion. Cx. pipiens pallens, Anopheles species, Aedes vexans nipponii, and Ae. japonicus were predominant over Cx. tritaeniorhynchus. Cx. tritaeniorhynchus, almost a solve vector species of JE virus in the southern part of Japan, is probably not a vector of the virus in Hokkaido. The collected mosquitoes (2,332 from 1985 and 1,403 from 1986) were processed for virus isolation but no JE virus was isolated. More extensive field studies are necessary to provide further information on the role of mosquito species other than Cx. tritaeniorhynchus in the transmission of JE virus in the northern limits of its range including Hokkaido. 相似文献
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T Kimijima Y Hashimoto H Kitagawa Y Kon M Sugimura 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1990,52(2):299-305
Studies were made on the distribution of lymphoid tissues and immunoglobulin (Ig: IgA, IgG and IgM)-containing cells (cIg: cIgA, cIgG and cIgM) and the localization of immunoglobulins (Igs) in the oviducal walls of laying hens. Lymphocyte accumulations were occasionally observed, located mainly in the middle infundibulum and in the regions from the isthmus to the vagina. The number of cIgG significantly predominated over that of cIgA or cIgM in the mucosal connective tissue of the magnum and the isthmus. In contrast, in the regions other than the magnum and the isthmus, these three types of cIg were fewer in number. Igs were localized in some superficial epithelial cells (SECs) and glandular cells (GlCs) of the oviduct. Many IgG-containing SECs were found in the infundibulum, the isthmus, and the cranial and major uterus. IgA- or IgM-containing SECs were rare throughout the oviduct. Three types of Ig-containing GlCs were numerously found in the magnum, though lymphocyte accumulations were scarce there. In the isthmus, many IgG-containing GlCs were found, while IgA- or IgM-containing GlCs were rarely observed. Ig-containing GlCs in the magnum were considerably decreased in number after the egg passage. The results suggest that the maternal Igs are transferred to the egg mainly through GlCs in the magnum of the chicken oviduct, and that the oviducal lymphoid tissues have little relationship to the passive immunity. 相似文献
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89.
Effects of a rice diet and phytase addition on growth performance,tissue weights,phosphorus and nitrogen retention,and on liver threonine dehydrogenase,malic enzyme and fatty acid synthase activities in broiler chicks
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This experiment was conducted to clarify the nutritional functions of rice and phytase addition for broiler chicks. Thirty‐six 7‐day‐old male chicks (ROSS 308 strain) were assigned to one of the four treatment groups: corn‐ or rice‐based diet groups and each diet with added phytase (2000 phytase units/kg diet) groups (corn + P or rice + P groups). The non‐phytate phosphorus (npP) content in the diets with added phytase was approximately half of the requirement. Body weight gain and feed intake in the rice group was significantly higher than those in the corn group. Breast and thigh muscle weights and nitrogen retention in the rice group were significantly higher than that in the corn group. Although the efficiency of phosphorus retention (%) in the corn + P group was significantly higher than that in the corn group, no significant difference was observed between the rice and rice + P groups. Liver threonine dehydrogenase activity in the corn group was significantly higher than in the other three groups. These results indicate that rice is superior to corn as a starter diet in broiler chicks, and that phytase action in the rice‐based diet was less than that in the corn‐based diet. 相似文献
90.
Soil CO2 levels reflect CO2 production and transport in soil and provide valuable information about soil CO2 dynamics. However, extracting information from soil CO2 profiles is often difficult because of the complexity of these profiles. In this study, we constructed a simple numerical
model that simulated soil CO2 dynamics and performed sensitivity analyses for CO2 production rates, soil water content and temperature, and gas diffusivity at the soil surface to clarify the relationships
among these parameters. Increased soil surface CO2 flux did not always coincide with higher soil CO2 concentrations; increased CO2 production at shallow depths had little effect on soil CO2 concentrations, while the opposite may be true for high levels of soil water content. Higher soil CO2 concentration did not always coincide with greater soil surface CO2 flux; under high soil water conditions, soil surface CO2 flux sometimes decreased despite increased soil CO2 concentration. Increases in soil water content did not always enhance both soil surface CO2 flux and soil CO2 concentration. Under high soil water conditions, increases in soil water content could lower soil surface CO2 flux and increase soil CO2 concentration. Increases in soil temperature resulted in greater soil surface CO2 flux and higher soil CO2 concentration in our simulation (extremely high temperatures were not assumed in this study). Gas diffusivity in very shallow
layers did affect, albeit weakly, soil CO2 concentration. The findings of this study may help direct future observations and aid in the interpretation of their results. 相似文献