Characterization of 4-nonylphenol-degrading bacterial consortium obtained from a textile wastewater pretreatment plant

4-Nonylphenol (4-NP) isomers are toxic and recalcitrant compounds often resulting, together with short-chain ethoxylated nonylphenol (NPnEO, where n is the number of ethylene oxide units), from NPnEO biodegradation in conventional activated sludge plants. In this work, a microbial consortium, defined as Consortium A, capable of removing 100 mg/L of 4-NP with no accumulation of metabolites with aromatic moiety was isolated from textile wastewaters after enrichment with 4-NP. The consortium showed remarkable degradation activities toward several short-chain NPnEO congeners. Culture-dependent techniques were used to isolate from the consortium twenty-six strains assigned to seven different amplified ribosomal DNA restriction analysis groups. Two- and three-member cocultures were prepared with the strains showing highest 4-NP-degrading capabilities, but neither the single strains nor the cocultures were as efficient in 4-NP degradation as Consortium A. FISH was used to characterize the microbial composition of Consortium A: it evidenced a strong occurrence of Proteobacteria and, in particular, of Gammaproteobacteria along with a relevant stability of the culture. Therefore, the isolated consortium has the potential of being used in the development of a biotechnological process for the tertiary treatment of effluents of activated sludge plants fed with NPnEO-contaminated wastewaters.     

Increased cellular apoptosis after chronic aqueous exposure to nonylphenol and quercetin in adult medaka (Oryzias latipes)

Increasing evidence suggests that sublethal effects of natural or xenobiotic chemicals in the environment may be mediated via the stimulation of apoptosis. To investigate whether apoptosis can be induced in fish by weakly estrogenic and androgenic chemicals, adult male Japanese medaka (Oryzias latipes) were exposed to 100 ppb of the estrogenic alkylphenol, 4-nonylphenol, and adult female medaka were exposed to 100 ppb of the aromatase-inhibiting bioflavonoid, quercetin, for 6 weeks. Exposure to nonylphenol and quercetin had no significant effect on the length, weight or condition factors compared to solvent (acetone) controls in male or female medaka. Apoptosis was evaluated in blinded histological sections of whole medaka using terminal dideoxynucleotidyl transferase dUTP nick end labeling (TUNEL) that labels nuclei of cells containing apoptotic (fragmented) DNA. There was a six-fold greater extent of apoptosis in spermatocytes, Sertoli cells and Leydig-homologue cells, but not in spermatids of testes from nonylphenol-exposed male medaka compared to testes of solvent controls. No significant differences in the extent of apoptosis were detected in intestine, liver or kidney from the same male fish. Quercetin-treated female medaka had a significantly increased number of atretic ovarian follicles, but no significant differences in the extent of apoptosis in intestine, liver or kidney. These results suggest that nonylphenol caused testicular degeneration via increased testicular cell apoptosis, while quercetin may be ovotoxic via increased follicular atresia.     

Short-term exposure to nonylphenol induces pancreatic oxidative stress and alters liver glucose metabolism in adult female rats

Nonylphenol is known to have estrogenic properties and has been reported to cause health hazards to animals and humans. The effects of nonylphenol on pancreas are not clearly elucidated. In this study, we sought to evaluate the effects of nonylphenol on the oxidative status of pancreas and consequential effects of nonylphenol on some of the end points of carbohydrate metabolism in the female rats. Rats were administered nonylphenol orally at the doses of 1.5, 15, and 150 mg/kg of body weight per day for 7 days. After 24 h of last dosing, the animals were sacrificed by cervical dislocation. The activities of pancreatic superoxide dismutase and catalase were significantly decreased with a concomitant increase in the levels of H2O2 and lipid peroxidation. Nonylphenol increased plasma insulin levels with a concomitant decrease in the levels of plasma glucose as compared to the control groups of rats. A dose-dependent increase in the activities of liver hexokinase and phosphofructokinase was recorded along with decreased activity of glycogen phosphorylase in liver. Western blot analysis revealed a significant decrease in the levels of GLUT-2. These results show that nonylphenol causes oxidative stress in pancreas and impairs liver glucose homeostasis.     

Effects of municipal effluents on serotonin and dopamine levels in the freshwater mussel Elliptio complanata

Sex differentiation and gametogenesis represent critical steps in the reproductive process and are subject to hormonal control by serotonin, dopamine and steroids such as estradiol-17beta and testosterone. The purpose of this study sought to examine the endocrine-disrupting activity that a primary-treated municipal effluent might have on the metabolism of biogenic amine levels. First, serotonin receptors transfected in Chinese hamster ovary (CHO) cells were used to screen for the presence of serotonin receptor agonist or antagonist. Second, one group of Elliptio complanata mussels were exposed to single compounds likely to be found in municipal wastewaters and another group was exposed in situ to the municipal effluent plume for 90 days in experimental cages. Results showed that solid phase C-8 extracts of surface water downstream a municipal effluent could activate the transport of serotonin by receptors at a distance of at least 5 km from its outfall thereby indicating the presence of serotonin mimics in the effluent dispersion plume. Levels of serotonin and monoamine oxidase (MAO) activity in nerve ganglia of mussels exposed for 90 days to the municipal effluent were, respectively, reduced and increased at a distance 10-km downstream. Injections of estradiol-17beta and nonylphenol in mussels decreased the levels of serotonin and dopamine, but increased MAO activity in the gonad and nerve ganglia. Exposure to estrogenic chemicals present in municipal effluents may therefore alter the normal metabolism of serotonin and dopamine, both of which are involved in sexual differentiation in bivalves and fish. Chemicals acting through E2 receptor-mediated pathways and serotonin receptors are likely to cause the observed effects.     

Changes in apoptotic rate and cell viability in three fish epidermis cultures after exposure to nonylphenol and to a wastewater sample containing low concentrations of nonylphenol

Three types of epidermal cultures of fish were used for toxicological investigations, a primary cell culture and a tissue culture prepared from the rainbow trout Oncorhynchus mykiss Walbaum and the cell line EPC, derived from a skin tumour of the carp Cyprinus carpio L. Two studies were carried out to compare the different culture systems. In the first cultures were incubated with nonylphenol and in the second set of experiments the cell cultures were exposed to a wastewater sample containing low concentrations of nonylphenol (NP). Both cell cultures were similarly sensitive to nonylphenol with respect to the endpoints cell viability (LC₅₀     

Effects of cadmium chloride and nonylphenol on the expression of StAR-related lipid transfer domain containing protein (START1) gene in aquatic midge, Chironomus riparius

We identified and characterized a partial cDNA of StAR-related lipid transfer domain containing protein gene from Chironomus riparius (CrSTART1) having homology with human MLN64 and Drosophila melanogaster START1 (DmSTART1) and evaluated the effects of cadmium chloride (Cd) and nonylphenol (NP) on its expression. Pfam analysis identified the presence of two StAR-related lipid transfer (START) domains in CrSTART1 having several conserved amino acid residues, characteristic of the MLN64 and DmSTART1. The mRNA expression of CrSTART1 was observed in all developmental stages. The modulation in the mRNA expression of CrSTART1 was investigated after exposure to different concentrations Cd (0, 2, 10, and 20 mg/L) and NP (0, 10, 50, and 100 μg/L) for different time intervals in fourth instar larvae of C. riparius. Significant downregulation of CrSTART1 mRNA was observed after exposure to 2, 10 and 20 mg/L of Cd for 24, 48 and 72 h. Significant upregulation of CrSTART1 was observed after exposure to 10 and 50 μg/L of NP for 24, and 48 h period. At 100 μg/L of NP significant upregulation of CrSTART1 was observed after 12 h and downregulated after 24, 48 and 72 h.     

Effects of nonylphenol on hematological parameters and immune responses in immature rainbow trout (Oncorhynchus mykiss)

ABSTRACT

This study investigated the effects of nonylphenol (NP) on hematological and immunological parameters in both male and female rainbow trout (Oncorhynchus mykiss). Fish were randomly distributed into six groups and administered with NP (10, 50 and 100 μg g^-1 week^-1 BW) and a single dose of 17-β estradiol (E2; 2 μg g^-1 week^-1 BW, positive control). The solvent controls received ethanol and coconut oil as a vehicle, while the controls were not injected. Red blood cells (RBCs) count, hematocrit (Hct), hemoglobin (Hb), white blood cells (WBCs), and lymphocytes demonstrated a NP dose-dependent decrease, whereas mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), monocytes, and neutrophils showed an increasing trend in both male and female fish 21 days post-treatment. Also, RBCs, Hb, MCHC, WBCs, and lymphocytes were significantly reduced (p<0.05) in E2 treated fish. Lysozyme, complement components (C3 and C4) and immunoglobulin M (IgM) were increased in fish sera subjected to 10 and 50 μg g^-1 NP, while these decreased in groups administered with 100 μg g^-1 NP and 2 μg g^-1 E2. Except for C4 level at 10 μg g^-1 NP, no significant differences were observed in hematological and immunological parameters of male and female in each treatment. Overall, a frequent exposure to NP could lead to adverse effects on fish immune-physiological functions which may cause serious ecological threats of fish natural population sustainability.     

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.     

Nonylphenol enhances apoptosis induced by serum deprivation in PC12 cells

Although nonylphenol is well known as an endocrine disrupting chemical, there is little information concerning biological effect of nonylphenol. In this study, we investigated effect of nonylphenol on apoptosis induced by serum deprivation in PC12 cells using TUNEL and DNA fragmentation assays. In addition, changes in contents of proapoptotic factors, Bad and Bax, and antiapoptotic factor, Bcl-2, and enzyme activity of caspase-3 were studied. Below 100 ng/ml of nonylphenol increased TUNEL signals, DNA fragmentation and content of proapoptotic factor, Bad as compared to those by serum deprivation without nonylphenol. Furthermore, addition of nonylphenol enhanced caspase-3 activity and Z-VAD, caspase-3 inhibitor, diminished such effect. These results indicated that below 100 ng/ml of nonylphenol enhanced apoptosis induced by serum deprivation via caspase-3 activation in PC12 cell.