Evaluation of the estrogenic effects of Bisphenol-A on male freshwater prawn Macrobrachium asperulum.

Bisphenol-A (BPA), a known endocrine-disrupting chemical that is distributed world wide, is extensively employed in industry, dentistry and consumer household products. This study was conducted to explore the estrogenic effects of BPA on the male freshwater prawn, Macrobrachium asperulum, by examining the daily survival rate, molting frequency, hepatosomatic index (HSI), and levels of vitellogenin-like protein. Results revealed that BPA can elicit the expression of vitellogenin-like protein (0.09 and 0.09 mg P·(mg protein)-1, respectively) in male organisms exposed to 0.1 and 1 ng l-1 BPA at day 7. Moreover, prawns were perceived to be sensitive to estrogenic compounds. Hence, it can be concluded that M. asperulum can be used as a species for biomonitoring, and levels of vitellogenin-like protein in males are a useful biomarker for detecting estrogenic contaminations.

Alterations of biochemical parameters in malformed Indian rice frogs, Rana limnocharis, from Southern Taiwan.

The purpose of this study is to investigate the factors that cause malformed frogs in upstream Kaoping river (KP site) and Tungkang river (T site) of Southern Taiwan. In this experiment, the activities of monooxygenase (MO), glutathione-S-transferase (GST), acetylcholinesterase (AchE) as well as the concentration of vitellogenin (Vg) in the liver were measured. Results show that activities of MO, GST and AchE, and Vg levels in normal frogs (male/female) were 0.09±0.02/0.09±0.01 DA min-1 mg-1 protein, 0.12±0.04/0.13±0.04DA min-1 mg-1 protein, 6.13±2.69/6.01±2.09 U mg-1 protein and 0.87±0.42/2.18±0.50 μg mg-1 protein, respectively. Activities of MO, GST and AchE, and Vg levels in malformed frogs (male/female) were 0.15±0.04/0.21±0.07DA min- 1 mg-1 protein, 0.27±0.08/0.30±0.12DA min-1 mg-1 protein, 4.59±2.71/5.19±3.74 U mg-1 protein and 1.46±0.61/ 3.15±0.88μg mg-1 protein, respectively in KP site, and were 0.16±0.69/0.18±0.07DA min-1 mg-1 protein, 0.21±0.07/0.24±0.08DA min-1 mg-1 protein, 5.13±4.58/3.94±1.33 U mg-1 protein and 2.23±1.47/4.11±1.63 μg mg-1 protein, respectively in T site. These results indicate that male and female malformed frogs in both rivers upstream are found with higher activities. No significant difference in AchE activity was found between normal and malformed frogs in this investigation. It is therefore reasonable to speculate that the organic chemicals released from agricultural activities are presumable the main factors that lead to the malformation of frogs.

Prevalence of malformed frogs in Kaoping and Tungkang river basins of southern Taiwan.

In this study, we found many amphibians with bizarre appearances, known as malformations in Pingtung County, southern Taiwan. For this investigation we collected frogs inhabiting the Kaoping and Tungkang river watersheds between February 2006 and June 2007. Among the total number of 10,909 normal frogs (i.e., anurans) collected during the investigation period, the Indian rice frogs (Rana limnocharis) account for the greatest number; next is the Chinese bullfrog (Rana rugulosa). Of all the 244 captured malformed frogs, the Indian rice frog account for the greatest proportion. These malformed frogs have their main distribution in upstream areas of these two rivers. Our result indicates that the appearance rate of malformed frogs is 1.8% in the upstream reaches of the Kaoping River and 2.6%, and 0.8%, respectively in the upstream and midstream reaches of the Tungkang river. The most-commonly-found malformation is the lack of palms, followed by the lack of appendages, exostosis, and a malformed appendicular. It is, therefore, reasonable to speculate that the causes for the malformation may be related to the increased organic pollutants and agricultural chemicals used in the upstream reaches of these two rivers.