Numerous diseases are induced by free radicals via lipid peroxidation, protein peroxidation and DNA damage. It has been known that a variety of plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum cuspidatum Sieb. et Zucc has antioxidant activity is unknown. In this study, dried roots of Polygonum cuspidatum were extracted by ethanol and the extract was lyophilized. Free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays were employed to study antioxidant activities. The results indicate that the IC50 value of Polygonum cuspidatum extract is 110 μg/ml in free radical scavenging assays, 3.2 μg/ml in superoxide radical scavenging assays, and 8 μg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum cuspidatum extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 641.1 ± 42.6 mg/g and 62.3 ± 6.0 mg/g. The results indicate that Polygonum cuspidatum extract clearly has antioxidant effects.
Although short-lived vertebrates can serve as model animals for understanding the mechanism of aging, whether the annual fish Nothobranchius rachovii is suitable for studying aging remains an open question. In this study, histochemical, biochemical, and genetic techniques were used to determine the age-related markers at three different developmental stages of the annual fish N. rachovii. Histochemical studies revealed that the expression of senescence-associated beta-galactosidase and accumulation of lipofuscin increased with age. In biochemical assays, lipid peroxidation and protein oxidation increased with age, whereas the activities of catalase, glutathione peroxidase, and superoxide dismutase decreased with age. Genetic analysis established that the activities of telomerase had no apparent relationship with age, but telomere lengths reduced with age from 11.5 +/- 1.98 to 3.58 +/- 0.74 kb. Taken together, these results indicate that the annual fish N. rachovii may be useful as an animal model for the study of aging.
Honeybees (Apis mellifera) are an attractive model system for studying aging. However, the aging level of worker honeybees from the field hive is in dispute. To eliminate the influence of task performance and confirm the relationship between chronological age and aging, we reared newly emerged workers in a thermostat at 34°C throughout their lives. A survivorship curve was obtained, indicating that workers can be reared away from the field hive, and the only difference between these workers is age. To confirm that these workers can be used for aging studies, we assayed age-related molecules in the trophocytes and fat cells of young and old workers. Old workers expressed more senescence-associated β-galactosidase, lipofuscin granules, lipid peroxidation, and protein oxidation than young workers. Furthermore, cellular energy metabolism molecules were also assayed. Old workers exhibited less ATP concentration, β-oxidation, and microtubule-associated protein light chain 3 (LC3) than young workers. These results demonstrate that honeybees reared in a thermostatic chamber can be used for aging studies and cellular energy metabolism in the trophocytes and fat cells of workers changes with advancing age.
Honeybees (Apis mellifera) form superparamagnetic magnetite to act as a magnetoreceptor for magnetoreception. Biomineralization of superparamagnetic magnetite occurs in the iron deposition vesicles of trophocytes. Even though magnetite has been demonstrated, the mechanism of magnetite biomineralization is unknown. In this study, proteins in the iron granules and iron deposition vesicles of trophocytes were purified and identified by mass spectrometry. Antibodies against such proteins were produced. The major proteins include actin, myosin, ferritin 2, and ATP synthase. Immunolabeling and co-immunoprecipitation studies suggest that iron is stored in ferritin 2 for the purpose of forming 7.5-nm diameter iron particles and that actin-myosin-ferritin 2 may serve as a transporter system. This system, along with calcium and ATP, conveys the iron particles (ferritin) to the center of iron deposition vesicles for iron granules formation. These proteins and reactants are included in iron deposition vesicles during the formation of iron deposition vesicles from the fusion of smooth endoplasmic reticulum. A hypothetical model for magnetite biomineralization in iron deposition vesicles is proposed for honeybees.
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