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Lanzhou, China

Fang S.,LanzhouUniversity | Li H.,LanzhouUniversity | Liu T.,LanzhouUniversity | Xuan H.,LanzhouUniversity | And 2 more authors.
Journal of Molecular Modeling | Year: 2014

Polychlorinated biphenyls (PCBs) are potentially hazardous to the environment because of their chemical stability and biological toxicity. In this study, we identified the binding mode of a representative PCB180 to human serum albumin (HSA) using fluorescence and molecular dynamics (MD) simulation methods. PCB180 bound exactly at subdomain IIIA of HSA based on the fluorescence study along with site marker displacement experiments. PCB180 also induced conformational changes that were governed mainly by hydrophobic forces. MD studies and free energy calculations also made important contributions to the understanding of the effects of an HSA-PCB180 system on conformational changes. The simulations on binding behavior proved that PCB180 was located only in subdomain IIIA. Hydrophobic interactions dominated the mode of binding behavior. The results obtained using the two methods correlated well with each other. Our findings provide a framework for elucidating the mechanisms of PCB180-HSA binding, and may also help in further research on the transportation, distribution, and toxicity effects of PCBs when introduced into human blood serum. © Springer-Verlag 2014. Source

Zhang X.,LanzhouUniversity | Zhang K.,LanzhouUniversity | Xu F.,LanzhouUniversity
Chinese Journal of Endemiology | Year: 2014

Objective: To observe the effects of fluoride on testicular cell cycle and cell apoptosis of male rats. Methods: Thirty-two healthy male Wistar rats, weighting 150-180 g, were randomly divided into 4 groups by body weight using random number table, normal sodium (control), the low-dose, medium-dose and high-dose groups(100, 200, 300 mg·kg-1·d-1 NaF, respectively) by intragastric administration for 90 days, and bodyweight was observed daily. After the last intragastric administration, all rats were killed by cervical dislocation. The testicular cell cycle and cell apoptosis were measured by flow cytometry. Results: After 30 days exposure, the difference of body weight between groups was statistically significant (F = 3.884, P < 0.05). The body weights in low- and medium-dose groups[(235.00 ± 14.56), (235.44 ± 24.99)g] were significantly increased than that of high-dose group[(206.00 ± 18.16)g, all P < 0.05]. There was no significant difference of body weight between the groups at 0, 60 and 90 days(F = 0.501, 0.578, 1.893, all P > 0.05). Compared with the control group[(43.10 ± 3.62)%], the percentages of G0/G1 stage cells were significantly increased in all the NaF-treated groups [(57.60 ± 7.26)%, (52.80 ± 3.20)%, (73.13 ± 4.08)%] and the percentages of S stage cells were significantly decreased in all the NaF-treated groups [(10.58 ± 2.58)%, (9.35 ± 0.35)%, (9.55 ± 0.50)%] compared to the control group[(19.23 ± 0.61)%, all P < 0.05]. On the other hand, the percentage of G2/M stage cells decreased significantly in high-dose group[(17.18 ± 2.21)%] compared with the control group[(36.34 ± 5.05)%, P < 0.05]. The testicular cell apoptosis ratios in all the NaF-treated groups were higher than that in the control group, but only in medium- and high-dose groups[(71.03 ± 2.30)%, (71.90 ± 2.16)%], the difference was statistically significant compared with the control group[(60.80 ± 2.34)%, all P < 0.05]. Conclusion: Chronic fluorosis can change testicular cell cycle and cell apoptosis and damage the reproductive system. Source

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