Transcriptomic and metabolomic integration to assess the response of gilthead sea bream (Sparus aurata) exposed to the most used insect repellent: DEET

Removal of contaminants of emerging concern by Wolffia arrhiza and Lemna minor depending on the process conditions, pollutants concentration, and matrix type

Research was carried out on the removal of a group of six contaminants of emerging concern: bisphenol A, N,N-diethyl-m-toluamide, diethylstilbestrol, triclosan, estrone and estradiol from the water matrix during contact with small floating macrophytes Wolffia arrhiza and Lemna minor. The optimal conditions for the process, such as pH, light exposure per day, and plant mass, were determined using the design of experiments chemometric approach based on central composite design. Experiments conducted under the designated optimal conditions showed that after 7 days, the removal efficiency equals 88-98% in the case of W. arrhiza and 87-97% in the case of L. minor, while after 14 days of the experiment, these values are 93-99.6% and 89-98%, respectively. The primary mechanism responsible for removing CECs is the plant uptake, with the mean uptake rate constant equal to 0.299 day-1 and 0.277 day-1 for W. arrhiza and L. minor, respectively. Experiments conducted using municipal wastewater as a sample matrix showed that the treatment efficiency remains high (the average values 84% and 75%; in the case of raw wastewater, 93% and 89%, and in the case of treated wastewater, for W. arrhiza and L. minor, respectively). Landfill leachate significantly reduces plants' ability to remove pollutants (the average removal efficiency equals 59% and 56%, for W. arrhiza and L. minor, respectively).

Proteomic analysis in the brain and liver of sea bream (Sparus aurata) exposed to the antibiotics ciprofloxacin, sulfadiazine, and trimethoprim

Antibiotics, frequently detected in aquatic ecosystems, can negatively impact the health of resident organisms. Although the study on the possible effects of antibiotics on these organisms has been increasing, there is still little information available on the molecular effects on exposed non-target organisms. In our study we used a label free proteomic approach and sea bream, Sparus aurata, to evaluate the effects of exposure to environmentally relevant concentrations of the antibiotic compounds ciprofloxacin (CIP), sulfadiazine (SULF) and trimethoprim (TRIM) produced at the protein level. Individuals of sea bream were exposed to single compounds at 5.2 ± 2.1 μg L-1 of CIP, 3.8 ± 2.7 μg L-1 of SULF and 25.7 ± 10.8 μg L-1 of TRIM for 21 days. After exposure, the number of differentially expressed proteins in the liver was 39, 73 and 4 for CIP, SULF and TRIM respectively. In the brain, there was no alteration of proteins after CIP and TRIM treatment, while 9 proteins were impacted after SULF treatment. The differentially expressed proteins were involved in cellular biological, metabolic, developmental, growth and biological regulatory processes. Overall, our study evidences the vulnerability of Sparus aurata, after exposure to environmentally relevant concentrations of the major antibiotics CIP, SULF and TRIM and that their chronic exposure could lead to a stress situation, altering the proteomic profile of key organs such as brain and liver.

Comparison of the cytotoxicity and zebrafish embryo toxicity of insect repellent ingredients: p-Menthane-3,8-diol synthesized by green chemistry from Eucalyptus citriodora and N,N-diethyl-meta-toluamide

Bio-sourced insect repellents are becoming more popular due to their safer applications. Known for its strong fly-repellent property, Cis, trans-para-menthane-3,8-diol (PMD) is the main component of the lemon eucalyptus essential oil and is synthesized from citronellal. In April 2005, US Centers for Disease Control approved two fly repellents that do not contain N,N-diethyl-meta-toluamide (DEET), including PMD. Due to the intentional and pervasive human exposure caused by DEET as insect repellent, concerns have been raised about its toxicological profile and potential harm to people. We hypothesized PMD would have a different toxicological profile than DEET. We synthesized PMD from Eucalyptus citriodora using green chemistry methods and analyzed its structures by 1H-NMR,13C-NMR, and GC/MS spectral methods. We used MTS assay to determine the percentage inhibition of PMD and DEET on keratinocyte (human epidermal keratinocyte [HaCaT]) cells. The xCelligence system was used and followed at real time. Effects of PMD and DEET on zebrafish embryo development were monitored and levels of lipid peroxidation, glutathione-S-transferase (GST), superoxide dismutase (SOD), and acetylcholinesterase (AchE) were evaluated at 72 h post-fertilization using spectrophotometric methods. Our results showed that while DEET inhibited human keratinocyte cell growth, while imporved cell viability and proliferation was exposed in PMD exposed group. In zebrafish embryos, PMD was less toxic in terms of development, oxidant-antioxidant status, and AChE activities than DEET. Based on these results we suggest an efficient method using green chemistry for the synthesis of PMD, which is found to be less toxic in zebrafish embryos and human keratinocyte cells.

Bioconcentration, biotransformation, and transcriptomic impact of the UV-filter 4-MBC in the manila clam Ruditapes philippinarum

Ultraviolet filters (UV-filters) are compounds extensively used in personal care products. These compounds are produced at increasing rates and discharged into marine ecosystems in unknown quantities and with no regulation, making them emerging contaminants. Among those, the UV-filter 4-Methylbenzylidene camphor (4-MBC) is used in a variety of personal care products such as sunscreens, soaps, or lipsticks. This high consumption has resulted in its presence in various environmental matrices at in concentrations ranging from ng to μg L-1. Very little is known, however, about the possible adverse effects in exposed non-target organisms. Our study presents novel data on the bioconcentration, toxicokinetics, and molecular effects of 4-MBC in a marine bivalve species of commercial interest, Ruditapes philippinarum (Manila clam). Organisms were exposed at two different concentrations (1.34 and 10.79 μg L-1) of 4-MBC for 7 days, followed by a 3-day depuration period (clean sea waters). Bioconcentration factors (BCF) were 3562 and 2229 L kg-1 for the low and high exposure concentrations, respectively, making this pollutant bioaccumulative according to REACH criteria. Up to six 4-MBC biotransformation products (BTPs)were identified, 2 of them for the first time. Transcriptomic analysis revealed between 658 and 1310 differently expressed genes (DEGs) after 4-MBC exposure. Functional and enrichment analysis of the DEGs showed the activation of the detoxification pathway to metabolize and excrete the bioconcentrated 4-MBC, which also involved energy depletion and caused an impact on the metabolism of carbohydrates and lipids and in the oxidative phosphorylation pathways. Oxidative stress and immune response were also evidenced through the activation of cathepsins and the complement system. Such elucidation of the mode of action of a ubiquitous pollutant such as 4-MBC at the molecular level is valuable both from an environmental point of view and for the sustainable production of Manila clam, one of the most cultivated mollusk species worldwide.

Recent advances in degradation of N,N-diethyl-3-toluamide (DEET)-an emerging environmental contaminant: a review

N,N-Diethyl-3-toluamide (DEET) is a commonly used insect repellent, which acts as an organic chemical contaminant in water and considered as an emerging contaminant which has been observed worldwide. It gets discharged into the environment through sewage waste. The various methods have been used to degrade DEET, such as UV based, ozonation, photocatalytic degradation, and biodegradation (based on the metabolic activity of fungi and bacteria). However, less research has been done on the degradation of DEET by deploying nanoparticles. Therefore, biodegradation and nanotechnology-based methods can be the potential solution to remediate DEET from the environment. This review is an attempt to analyze the routes of entry of DEET into the atmosphere and its environmental health consequences and to explore physical, chemical, and biological methods of degradation. Furthermore, it focuses on the various methods used for the biodegradation of the DEET, including their environmental consequences. Future research is needed with the application of biological methods for the degradation of DEET. Metabolic pathway for biodegradation was explored for the new potent microbial strains by the application of physical, chemical, and microbial genomics; molecular biology; genetic engineering; and genome sequencing methods.