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1.
Purpose: To test the effects of short-term exposure of aquatic organisms to electric field (EF) with negligible magnetic component.

Materials and methods: We built a plate capacitor that served as a source of EF of strengths that can be found in nature near transmission lines. We exposed two cultured protist species Euglena viridis and Paramecium caudatum to EFs for 24?hours and monitored their abundance, morphology, intracellular superoxide anion (by dihydroethidium [DHE]), hydrogen peroxide by (H2DCF) and lipid peroxidation (MDA) contents, catalase (CAT) and superoxide dismutase (SOD) activity.

Results: We found that even short-term exposure to low strength EF causes changes in population abundance, morphology and oxidative stress response in both species. As the EF strength increased, abundance of both species decreased. However, at weaker EFs, fission rates were seemingly promoted. We noted a decrease in size in both organisms in directions perpendicular to their fission planes correlated with EF strength. DHE and H2DCF fluorescence intensity and SOD activity were higher in organisms exposed to the stronger EFs.

Conclusions: We suggest that the electric component of the field, rather than the magnetic, is the main cause of all the noted effects. As a result, aquatic organisms should be given greater importance in studies assessing the effects of EMFs in spite of the attenuating effects of water to EF strengths.  相似文献   

2.
《Pharmaceutical biology》2013,51(4):403-407
Context: In folk medicine in China, Desmodium caudatum (Thunb.) DC (Leguminosae) has been used to treat febrile diseases, rheumatic arthritis, and bacillary dysentery; nevertheless, there have been no reports on the analgesic, antipyretic, and anti-inflammatory effects of this plant in animals.

Objective: To investigate the analgesic, anti-inflammatory, and antipyretic activities of D. caudatum extract (DCE) in animals.

Materials and methods: The analgesic effect of DCE was measured in mice using the acetic acid-induced writhing test and the hot-plate test. The anti-inflammatory activity was assessed using the carrageenan-induced rat paw edema model and the dimethylbenzene-induced mouse inflammation model. The antipyretic effect was estimated using the lipopolysaccharide (LPS)-induced rat fever model. In addition, the acute oral toxicity of DCE was studied.

Results: DCE significantly and dose-dependently inhibited the writhing responses in mice, increased reaction time in mice in the hot-plate test, reduced carrageenan-induced paw edema in rats and the dimethylbenzene-induced ear edema in mice, and attenuated LPS-induced fever in rats. Furthermore, no death was observed when mice were orally administered DCE up to 40?g/kg.

Discussion and conclusion: DCE possesses evident analgesic, anti-inflammatory, and antipyretic activities, and has a favorable safety, which supports the use of D. caudatum as an analgesic, anti-inflammatory and antipyretic drug in folk medicine.  相似文献   
3.
《Journal of neurogenetics》2013,27(4):239-252
A new mutant of Paramecium letraurelia has been isolated with a profound defect in the regulation of membrane potential. This mutant, restless, hyperpolarizes as a potassium electrode below 8 mM external K + whereas wild-type cells can maintain a constant resting cell potential independent of low external K + concentration, restless dies in solutions of low K+ concentration in which wild-type can survive indefinitely. restless is not allelic to mutations that affect the depolarization-dependent Ca2 + current, the Ca2 + -activated K + current, and the Ca2 + -activated Na + current. The results suggest that restless is a new class of mutant affecting a K + conductance hitherto not characterized genetically in Paramecium.  相似文献   
4.
目的:研究虎眼万年青多糖含量测定方法。方法:采用比色法,用紫外分光光度计测定虎眼万年青多糖的含量。结果:虎眼万年青多糖的线性范围是0.4083~0.8166mg,重复性含量为8.5%,RSD=0.7%(n=6);平均回收率为97.4%,RSD=1.1%(n=6);精密度RSD=0.1%(n=6);45min内样品吸光度较稳定,在24h样品稳定。结论:通过对虎眼万年青多糖含量的研究,确定了虎眼万年青多糖含量的测定方法。  相似文献   
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6.
The use of the established mutagenesis assay in Paramecium as a prescreen for hazardous environmental particles is described. Since these protozoans ingest particles of the size respired by animals and man, the biological effects of the respirable fraction of fly ash particles were monitored in particle-feeding eukaryotic cells. Fly ash from coal combustion was utilized for these studies and was found to be mutagenic. The effects of physical and chemical treatment of the particle mutagenicity provided evidence for both heat-stable, heat-labile and acid extractable mutagenic agents.  相似文献   
7.
1. In organisms ranging from paramecia to mammals, hypoxia elicits a regulated decrease in body temperature (Tb). A decrease in Tb is an important adaptation to hypoxia primarily because it lowers metabolic rate when oxygen supply is limited, thus facilitating survival. 2. Although this beneficial response is extremely widespread among taxa, little is known of the cellular mechanisms that mediate hypoxia-induced decreases in Tb. This is due, in large part, to the extreme complexity of vertebrate thermoregulatory systems. 3. The thermoregulatory system of the unicellular paramecium is much simpler than that of vertebrates, yet it responds similarly to hypoxia. Research has explored the functional importance of hypoxia-induced decreases in Th. In addition, a number of possible mediators and signalling pathways in hypoxia-induced reductions in Tb have been assessed. 4. In Paramecium caudatum, hypoxia appears to exert its thermoregulatory effects by inhibiting oxidative phosphorylation. Decreases in intracellular [ATP] and pH may be important intermediate signals. In addition, an endogenous opioid system appears to help mediate hypoxia-induced changes in thermoregulatory behaviour.  相似文献   
8.
9.
应用荧光逆行标记分别与荧光组化(FAGLU)和AChE-药理组化相结合技术,研究了树鼩中脑腹侧被盖区向尾状核头部的DOPA能和ACHE-阳性纤维投射。结果表明:树鼩中脑腹侧被盖区除分别向同侧和对侧尾状核头部发出DOPA能纤维投射外,还向同侧尾状核头部发出AChE阳性投村纤维;此外,腹侧被盖区存在着向双侧尾核头部发出分叉投射纤维的DOPA能细胞。  相似文献   
10.
A diversity of time when increase in mortality after conjugation occurs during the lifespan was found in subclones of three stocks of Paramecium caudatum. A possible micronuclear contribution to the increase in sterility has been investigated by micro-nuclear transplantation. We found two classes of micronuclei in aged clones: those that can function normally if the cytoplasmic environment is young, and those that cannot, even in a young cytoplasmic environment. The results indicate that in the former, the age-dependent increase in sterility is due to a deleterious macronucleus and/or cytoplasm, and in the latter it is due to micronuclear damage. The micronuclear damage in aged clones is probably induced by a deleterious cytoplasmic environment because aged clones with transplanted young micronuclei showed an abrupt decrease in progeny survival between 14 and 42 cell divisions after transplantation. Overall, the micronucleus seems not to be a source of age-related damage but rather is subjected to damage from macronuclear and/or cytoplasmic sources.  相似文献   
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