Endocrine-disrupting effects of nonylphenol in the newt, Triturus carnifex (Amphibia, Urodela)

The aim of our study was to verify whether environmental concentrations of nonylphenol influenced the adrenal gland of Triturus carnifex. Newts were exposed to 19 μg/L nominal concentration of nonylphenol throughout the periods of December-January and March-April, corresponding to different stages of the chromaffin cell functional cycle. The morphological features of the steroidogenic and chromaffin tissues, and the serum levels of ACTH, aldosterone, corticosterone, norepinephrine and epinephrine were evaluated. Nonylphenol did not influence ACTH serum levels. During the two periods examined, the steroidogenic tissue had the same reaction: the quantity of cytoplasmic lipids, and the corticosteroid serum levels, decreased, suggesting the inhibition of synthesis and release of corticosteroids. During the two periods examined, the chromaffin tissue reacted differently to nonylphenol. During December-January, the numeric ratio of norepinephrine granules to epinephrine granules, and the epinephrine serum levels, increased, suggesting the stimulation of epinephrine release. During March-April, the numeric ratio of norepinephrine granules to epinephrine granules did not change, and the norepinephrine serum levels decreased, suggesting the inhibition of norepinephrine release. Our results show that nonylphenol influences the activity of the newt adrenal gland; considering the physiological role of this gland, our results suggest that nonylphenol may contribute to amphibian decline.     

The endocrine disruptor nonylphenol preferentially blocks cyclooxygenase-1

The anthropogenic chemicals nonylphenol, bisphenol A, phthalic acid benzyl n-butyl ester, phthalic acid di-n-butyl ester and phthalic acid di(2-ethylhexyl) ester have been shown to possess sex hormone-like activity. To explore the possible actions of these chemicals on the autacoid synthesis in the body, we investigated the effects of nonylphenol, bisphenol A, phthalic acid benzyl n-butyl ester, phthalic acid di-n-butyl ester and phthalic acid di(2-ethylhexyl) ester on the activities of cyclooxygenase-1 and -2. Bisphenol A and all three phthalic acid derivatives had no significant effect on the cyclooxygenase-1 and -2 activities up to 100 microM. On the other hand, nonylphenol exhibited a marked inhibition on the cyclooxygenase-1 activity (10-100 microM nonylphenol, 7-95% inhibition), with no detectable change in the activity of cyclooxygenase-2. The inhibition patterns for the substrate, arachidonic acid, and a cofactor, phenol, were competitive and uncompetitive, respectively. These results suggest that nonylphenol can be a selective inhibitor of cyclooxygenase-1 activity.     

四湖总干渠环境雌激素不同浓度江段鱼繁殖生物学比较研究

选取湖北四湖总干渠污染水平不同的3个江段(A、B、C), A离源头较近, B位于一农药厂排污口下方, C位于一城镇居民排污口下方, 比较鱼繁殖群体的生物学特征。A江段水体中未检测出环境雌激素, 而B、C两江段主要含有壬基酚和双酚A, 两种污染物总浓度在20 μg/L左右。与A江段相比, B、C江段鱼繁殖群体中雌性个体的比例明显较高, 卵粒较小; 雄性个体精巢组织间隙增大, 精原细胞和精子细胞密度低; 肝体指数增大、肝组织出现大量空泡, 肝细胞密度降低等特点。壬基酚和双酚A已被证明具有显著的雌激素活性和生殖毒性。因此, B、C江段壬基酚和双酚A环境雌激素浓度较高可能是导致鱼繁殖群体生物学特征改变的重要原因。     

Harnessing the power of enzymes for environmental stewardship

Enzymes are versatile catalysts with a growing number of applications in biotechnology. Their properties render them also attractive for waste/pollutant treatment processes and their use might be advantageous over conventional treatments. This review highlights enzymes that are suitable for waste treatment, with a focus on cell-free applications or processes with extracellular and immobilized enzymes. Biological wastes are treated with hydrolases, primarily to degrade biological polymers in a pre-treatment step. Oxidoreductases and lyases are used to biotransform specific pollutants of various nature. Examples from pulp and paper, textile, food and beverage as well as water and chemical industries illustrate the state of the art of enzymatic pollution treatment. Research directions in enzyme technology and their importance for future development in environmental biotechnology are elaborated. Beside biological and biochemical approaches, i.e. enzyme prospection and the design of enzymes, the review also covers efforts in adjacent research fields such as insolubilization of enzymes, reactor design and the use of additives. The effectiveness of enzymatic processes, especially when combined with established technologies, is evident. However, only a limited number of enzymatic field applications exist. Factors like cost and stability of biocatalysts need to be addressed and the collaboration and exchange between academia and industry should be further strengthened to achieve the goal of sustainability.     

Effects of nonylphenol on the production of progesterone on the rats granulosa cells

We investigated the effects of nonylphenol (NP) on release of progesterone (PG) by granulosa cells (GCs) of rats in vitro and in vivo. First, GCs were treated with different doses of NP for 2-24 h alone or with human chorionic gonadotropin (hCG). Maximal PG secretion at 8 h noted, GCs were treated for 2 h with hCG, 8-bromo-adenosine 3':5'-cyclic monophosphate (8-Br-cAMP), forskolin, A23187, nifedipine, and pregnelonone to evaluate the NP effects on PG steroidogenesis. Results indicated that all of chemicals except nifedipine stimulated the PG release compared to vehicle, but the stimulatory effects could not be enhanced by different doses of NP. Second, GCs were isolated to react with hCG, 8-Br-cAMP and PD98059 after the immature female rats gavaged with different doses of NP (ONP) for 7 days. PG released significantly when rats treated with oral NP 100 compared to 0 μg/kg/day. Third, GCs collected from the female offspring of mother rats which gavaged with NP 100 μg/kg/day for 21 days during pregnancy (MONP) reacted with different doses of chemicals. The results showed that PG release in the presence of chemicals was significantly higher in ONP and MONP groups; however, this stimulation was not noted by dose-dependent. The plasma concentration of PG was higher in ONP (100 μg/kg/day) and the offspring of MONP groups. The steroidogenic acute regulatory (StAR) protein expressed higher in all three groups by Western blotting. This study results indicated that low dose of NP stimulated PG release in rat GCs by activation of StAR protein.     

Removal and biodegradation of nonylphenol by immobilized Chlorella vulgaris

The removal and biodegradation of nonylphenol (NP) by alginate-immobilized cells of Chlorella vulgaris were compared with their respective free cultures. The effects of four cell densities of 10(4) per algal bead were investigated, as were the four algal bead concentrations, with regard to the removal and biodegradation of NP. Although immobilization significantly decreased the growth rate and NP's biodegradation efficiency of C. vulgaris, NP removal over a short period was enhanced. The NP removal mechanism by immobilized cells was similar to that by free cells, including adsorption onto alginate matrix and algal cells, absorption within cells and cellular biodegradation. The optimal cell density and bead concentration for the removal and biodegradation of NP was 50-100×10(4) cells algal bead(-1) and 2-4 beads ml(-1) of wastewater, respectively. These results demonstrated that immobilized C. vulgaris cells under optimal biomass and photoautotrophic conditions are effective in removing NP from contaminated water.     

Nonylphenol modulates expression of androgen receptor and estrogen receptor genes differently in gender types of the hermaphroditic fish Rivulus marmoratus

To uncover the effect of estrogenic chemicals [4-nonylphenol (NP) and bisphenol A (BisA)] on the expression of androgen receptor (AR) and estrogen receptors (ERalpha and ERbeta) in the hermaphroditic fish Rivulus marmoratus, we cloned the full length of the cDNAs encoding AR, ERalpha, and ERbeta from gonadal tissue of R. marmoratus and analyzed the modulation of expression of these genes following exposure to estrogenic chemicals using real-time RT-PCR. R. marmoratus AR, ERalpha, and ERbeta genes showed a high similarity to the relevant fish species on amino acid residues, respectively. Rm-ERalpha and Rm-ERbeta cDNAs included a serine-rich region when compared to other teleost fish ER genes. Tissue-specific expression of Rm-AR and Rm-ERbeta mRNAs in adult hermaphrodite R. marmoratus was high in the gonad, while Rm-ERalpha mRNA was high in the liver based on real-time RT-PCR. In addition, Rm-AR and Rm-ERalpha mRNAs increased along with developmental stage from stage 3 (5 dpf) to hatching, while Rm-ERbeta mRNA increased from stage 2 (2 dpf). To uncover the effect of estrogenic chemicals on R. marmoratus, we exposed the fish to NP (300 microg/l) and BisA (600 microg/l) for 96 h. Significant down-regulation of Rm-AR, Rm-ERalpha, and Rm-ERbeta mRNA was observed in gonadal tissue after exposure to NP but not BisA. In the liver, there were gender differences in gene expression after EDC exposure. These results demonstrate that expression patterns of the Rm-AR, Rm-ERalpha, and Rm-ERbeta genes in the hermaphroditic fish, R. marmoratus, vary according to tissue and developmental stage as well as the specificity of environmental estrogenic chemicals. These genes can be useful as molecular biomarkers in assessing the potential impact of estrogenic compounds using this species as a model system.     

Biodegradation of nonylphenol in mangrove sediment

This study investigated the biodegradation of nonylphenol (NP) in mangrove sediments collected at five sites along the Tanshui River in northern Taiwan. NP biodegradation rate constants (k₁) and half-lives (t_1/2) ranged from 0.039 to 0.139 day⁻¹ and 5.0 to 17.8 days, respectively. The biodegradation of NP was enhanced by the addition of yeast extract, hydrogen peroxide, brij 35, sodium chloride, or cellulose. However, NP biodegradation was inhibited by the addition of humic acid, heavy metals, or phthalic acid esters (PAEs). Of the microorganism strains isolated from the mangrove sediment, we found that strains A9, A10 and A13 (all identified as Bacillus sp.) expressed the best biodegrading ability. NP biodegradation rate constants (k₁) and half-lives (t_1/2) by the three strains ranged from 0.291 to 0.630 day⁻¹ and 1.1 to 2.4 days, respectively. The highest NP biodegradation rate was found in the sediment with the inoculation containing strains A9, A10 and A13, whereas the sediment without any inoculation had the lowest biodegradation rate.