Exosomes Derived from Hydroquinone-transformed Human Bronchial Epithelial Cells Inhibited Recipient Cell Apoptosis by transferring miR-221.

OBJECTIVE: Although benzene is a confirmed environmental carcinogen, the mechanism of its carcinogenicity remains largely unclear. The suggested oncogene, miR-221, is elevated and plays important roles in various tumors, but its role in benzene-induced carcinogenesis remains unknown. METHODS: In the present study, we constructed hydroquinone (HQ, a representative metabolite of benzene with biological activity)-transformed malignant cell line (16HBE-t) and analyzed the level of miR-221 in it with qRT-PCR. Exosomes from 16HBE-t cells incubated with or without an miR-221 inhibitor were isolated by ultracentrifugation, characterized by transmission electron microscopy and laser scanning confocal microscope, and then transfected into 16HBE cells. The effects of exosomal miR-221 on apoptosis induced by HQ in recipient cells were determined using flow cytometry. RESULTS: The amount of miR-221 in 16HBE-t was significantly increased compared with controls. When recipient cells ingested exosomes derived from 16HBE-t, miR-221 was increased, and apoptosis induced by HQ was inhibited. Blocking miR-221 in 16HBE-t using an inhibitor did not significantly alter miR-221 or apoptosis in recipient cells. CONCLUSION: Exosomal miR-221 secreted by 16HBE-t inhibits apoptosis induced by HQ in normal recipient cells.

The effects of enhanced ultraviolet-B radiation on the biology of green and brown morphs of Sitobion avenae (Hemiptera: Aphididae).

The effects of enhanced UV-B radiation on the biology of green and brown morphs of Sitobion avenae (F.) (Hemiptera: Aphididae) were tested under laboratory conditions. The two S. avenae morphs were exposed directly to different doses (0, 216, 432, and 864 kJ/m(2)) of artificial UV-B. Under low doses of UV-B (216 kJ/m(2)), the nymphal development period was significantly shorter, whereas mean relative growth, total fecundity, and gross reproductive rate were significantly higher for both aphid morphs compared with those morphs under control treatments (0 kJ/m(2)). Under high doses of UV-B (432 kJ/m(2) and/or 864 kJ/m(2)), the nymphal development period was significantly longer, whereas the reproductive period, postreproductive period, difference in weight, mean relative growth, and life table parameters were significantly reduced for both aphid morphs. Moreover, the nymphal development period was significantly shorter and the differences in weight, mean relative growth, total fecundity, and life table parameters were significantly higher for the brown morph under high doses of UV-B compared with the green morph. The results showed that enhanced UV-B affects the performance of the green and brown S. avenae morphs from positively to negatively. The brown morph exhibited stronger adaptability than the green morph at high doses of UV-B.

Life table evaluation of survival and reproduction of the aphid, Sitobion avenae, exposed to cadmium.

The effects of cadmium (Cd) on the development, fecundity, and reproduction of the grain aphid, Sitobion avenae Fabricius (Hemiptera: Aphididae) were estimated by constructing a life table of S. avenae exposed to Cd. The concentrations of Cd in the soil were as follows: 0, 10, 20, 40, 80, and 160 mg/kg. The correlation analysis of the Cd concentration in soil and wheat revealed that the amount in the wheat increased with the increase of Cd concentrations in soil. The results indicated that, the latter part of the reproduction period was significantly affected by Cd, according to the curve of the total survival rate (l(x)). The net reproductive rate (R(0)), innate capacity of increase (r), and finite rate of increase (λ) of S. avenae all decreased under the stress of Cd, and were lowest at a Cd concentration of 20 mg/kg. Cd also negatively affected fecundity and m(x) (the number of offspring produced by an individual female). At 20 mg/kg, the decline of them was most obvious. In conclusion, survival and reproduction of S. avenae were inhibited under the treatment of the heavy metal Cd. Sitobion avenae was more sensitive to Cd at concentration of 20 mg/kg compared to the other concentrations. This concentration can be used to examine the mechanisms behind population genetics and biological mutation of S. avenae when exposed to heavy metal.

[Effects of UV-radiation on biological characteristics of different body-color biotypes of Sitobion avenae (Fab.)].

UV-radiation exerts strong selection stress on the evolution of aphid populations, and thus, leads to their genetic differentiation. However, the effects of UV-radiation on different body-color biotypes of aphids are still ambiguous. In this study, new-born nymphae of red and green biotypes of Sitobion avenae were placed on two wheat varieties (Xiaoyan-22 and Astron), bred in an artificial bioclimatic chamber under strict controlled conditions (at 15 degrees C, 20 degrees C, and 25 degrees C, and treated with 30 W lamp of UV-B for 30 min per day for 5 days), and their development duration, mass, and mean relative growth rate were measured. The results showed that at lower temperature, UV-radiation delayed the growth of green biotype aphid on Xiaoyan-22 and Astron significantly; while at higher temperature, UV-radiation significantly delayed the growth of red biotype aphid on Xiaoyan-22, but had lesser effects on the growth of the two biotypes on Astron, illustrating that different biotypes of aphids had different responses to UV-radiation, and the responses were correlated to temperature and wheat varieties.