Journal of Xenobiotics — Open Access Journal

The release of nanoplastics (NPs) from the weathering and degradation of plastics is an important environmental concern. Given their small sizes and their invasiveness in cells, methods for the detection of NPs in biological tissues are urgently needed. A simple fluorescence-based methodology for the detection of polystyrene NPs in biological tissues is proposed. The commercially available molecular rotor probe 9- (dicyanovinyl)-julolidine (DCVJ) has the properties to detect changes in hydrophobicity and microviscosity and was used to detect NPs. Increasing concentrations of 50 and 100 nm NPs in water and in tissue extracts were mixed with the DCVJ probe and the emission spectra determined between 480-800 nm at 450 nm excitation. The data revealed that NPs induces a second emission peak at 620 nm that differed from the normal spectra of the biological extract at 500 nm. A significant linear relationship was obtained for NPs of both sizes (r=0.98; P<0.001) with a theoretical limit of detection of 65 ng/mL. A simple and rapid microplate spectrofluorometric method for the semi-quantitative detection of polystyrene NPs in biological tissues is thus presented. Full article

Mangrove rivulus, Kryptolebias marmoratus, is a hermaphrodite fish capable of self-fertilization. This particularity allows to naturally produce highly homozygous and isogenic individuals. Despite the low genetic diversity, rivulus can live in extremely variable environments and adjust its phenotype accordingly. This species represents a unique opportunity to clearly distinguish the genetic and non-genetic factors implicated in adaptation and evolution, such as epigenetic mechanisms. It is thus a great model in aquatic ecotoxicology to investigate the effects of xenobiotics on the epigenome, and their potential long-term impacts. In the present study, we used the mangrove rivulus to investigate the effects of the neurotoxin ß-N-methylamino-L-alanine (BMAA) on larvae behaviors after 7 days exposure to two sub-lethal concentrations. Results show that BMAA can affect the maximal speed and prey capture (trials and failures), suggesting potential impacts on the organism’s fitness. Full article

Fungal spores are ubiquitous in indoor and outdoor air and their diversity and biomass quantity vary depending on the geographical location, environmental con- ditions, and the presence of sources such as hay, agricultural crops or growth on build- ing material [...]
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The UV-filter benzophenone and the anti-inflammatory diclofenac are commonly detected in the environment. The aim of this study was to assess the multigenerational effects of chronic exposure to low concentrations of these chemicals on toxicity and DNA methylation levels in the copepod Gladioferens pectinatus. Acute toxicity tests were conducted to determine the sensitivity of G. pectinatus to the chemicals. All chemicals impacted breeding, hatching and egg viability. Diclofenac (1 mg.L^-1) reduced the number of eggs per gravid female. Benzophenone (0.5 mg.L^-1) decreased egg hatching success. Exposure to the reference toxicant copper (0.02 mg.L^-1) led to unsuccessful hatching. Effects on DNA methylation was estimated by the percentage of 5- methylcytosine. The treatments resulted in strong differences in DNA methylation with increased methylation in the exposed animals. The two chemicals impacted both egg viability and the induction of differential DNA methylation, suggesting potential intra- and trans-generational evolutionary effects. Full article

Thiamethoxam (TMX), a second-generation neonicotinoid insecticide, is one of the most widely used insecticides in Algeria. The present study assessed the effects of repeated subchronic exposure to the commercial formulation of thiamethoxam (Actara^®, 25% WG) in albino male rats. The toxic effects of thiamethoxam (TMX) were studied biochemically and histopathologically. Twenty-eight male albino rats weighing between 226 and 243 g were randomly assigned to four groups. One group served as control, and the other three were served as experimental groups administered a neonicotinoid thiamethoxam (TMX; 26, 39 and 78 mg/kg/day) for 6 weeks. The effects of the insecticide on various biochemical parameters were evaluated at 2, 4 and 6 weeks. Histopathological studies were carried out in the liver, kidney, cerebellum and hippocampus at the end of the experiment. Changes in biochemical parameters glucose, ALT (alanine aminotransferase), AST (aspartate aminotransferase), γGT (gamma-glutamyltransferase) ALP (alkaline phosphatase) urea and creatinine were observed in treated-groups in a dose dependent manner when compared to the control. Histopathological alterations were more intense in male rats from the TMX high dose group than those from group 2 and 3. Based on these results, subchronic oral administration of thiamethoxam altered the biochemical parameters, which correlated with histopathological changes in the liver kidney and brain. Full article

Nearly 5 billion liters of untreated sewage was intentionally discharged in November 2015 in the St. Lawrence River (Canada) for reasons of major sewer system maintenance and to avoid jeopardizing the Montreal wastewater treatment plant [...]
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The purpose of this study was to examine the effects of dissolved and particulate compounds on quorum sensing in the marine luminescent bacterium Aliivibrio fisheri. Bacteria were exposed to increasing concentrations of CuSO₄ (Cu²⁺), gadolinium chloride (Gd³⁺), 20-nm silver nanoparticles (nanoAg) and 1-3 μm microplastic polyethylene beads for 250 min. During this period, luminescence measurements were taken at 5-min intervals. Toxicity was first examined by measuring luminescence output at 5-min and 30-min incubation time. Based on the effective concentration that decreases luminescence by 20% (EC20), the compounds were toxic at the following concentrations in decreasing toxicity: Cu²⁺ (3.2 mg/L) < nanoAg (3.4 mg/L, reported) < Gd³⁺ (34 mg/L) < microplastics (2.6 g/L). The data revealed that luminescence changed non-linearly over time. In control bacteria, luminescence changed at eight specific major frequencies between 0.04 and 0.27 cycle/min after Fourier transformation of time-dependent luminescence data. The addition of dissolved Cu²⁺ and Gd³⁺ eliminated the amplitude changes at these frequencies in a concentration-dependent manner, indicating loss of quorum sensing between bacteria at concentrations below EC20. In the presence of nanoAg and microplastic beads, the decreases in amplitudes were modest but compressed the luminescence profiles, with shorter frequencies appearing at concentrations well below EC20. Thus, loss of communication between bacteria occurs at non-toxic concentrations. In addition, with exposure to a mixture of the above compounds at concentrations that do not produce effects for Gd3+, nanoAg and microplastics, Cu²⁺ toxicity was significantly enhanced, suggesting synergy. This study revealed for the first time that small microplastic particles and nanoparticles can disrupt quorum sensing in marine bacteria. Full article

The determination of changes in gene expression profiles with xenobiotic dose will allow identifying biomarkers and modes of toxicant action. The harbor seal (Phoca vitulina) 11B7501 B lymphoma cell line was exposed to 1, 10, 100, 1000, 10,000, or 25,000 μg/L 17α-ethinyl estradiol (EE₂, the active compound of the contraceptive pill) for 24 h. Following exposure, RNA was extracted and transformed into cDNA. Transcript expression in exposed vs. control lymphocytes was analyzed via RT-qPCR to identify genes with altered expression. Our analysis indicates that gene expression for all but the reference gene varied with dose, suggesting that different doses induce distinct physiological responses. These findings demonstrate that RT-qPCR could be used to identify immunotoxicity and relative dose in harbor seal leukocytes. Full article

3β, hydroxy-lup-20(29)-en-28-oic acid (Betulinic acid), a pentacyclic lupane-type triterpene has diverse pharmacological functions both in vitro and in vivo. The present study focuses its protective effect on polycyclic aromatic hydrocarbon (7,12- Dimethylbenz(a)anthracene or DMBA) induced alterations in membrane bound ATPases, detoxification enzymes and antioxidant enzymes in stomach and lungs of female Sprague Dawley rats. Healthy female Sprague Dawley rats were randomly assorted into six groups and the treatments were given orally for 7 weeks on alternate days. It was observed that betulinic acid facilitated the downregulation of elevated membrane bound ATPases (Na⁺/K⁺- ATPase, Ca²⁺-ATPase and Mg²⁺-ATPase) in DMBA administered rats. Likewise, the detoxification enzymes as well as antioxidant enzymes were modulated to normalcy in rats. Overall, betulinic acid was seen to be effective modulator of DMBA induced alterations in biochemical parameters. Full article

One of the most remarkable features of immune systems through many species is the capacity of phagocytes to produce diverse form of oxidizing agents in order to destruct invaders [...]
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Ecotoxicological effects of industrial chemicals (Rig wash, Oil eater, Nalco, Glycol™) and pesticides (Propoxur, Deltamethrin, Atrazine, Furadan) on Tilapia guineensis (fish) and Aporrectodea longa (earthworms) were tested using the Organisation for Economic Cooperation and Development (OECD) # 203 and 207 protocols. The water and soil ratings indicate that the test chemicals were toxic to the organisms. The estimated 96 hour lethal concentration LC₅₀ values for Rig wash, Oil eater, Nalco EC1304A/COT 505, Glycol, Propoxur, and Deltamethrin were 26.34±0.46, 6.02±0.30, 3.07±0.14, 1.31±0.01, 20.91±0 and 0.01±0 mg/l respectively. In the earthworm bioassay, the estimated 14-day LC₅₀ values for Rigwash, Oil eater, Nalco EC1304A/COT 505, Glycol, Atrazine and Furadan were 80.05±3.5, 151.55±10.7, 172.63±14.2, 63.72±2.43, 4.97±0 and 0.29±0 mg/kg respectively. Safety factors are arbitrarily built in around the LC₅₀ values in order to arrive at environmentally tolerable concentrations. The concentration of a chemical in the receiving environment should not exceed 10% of the L₅₀. The organisms exposed to the test chemicals showed significant difference when compared with the levels measured in the control group. The observed sensitivity of the test organisms to the chemicals indicates that adherence to standard safety limits/measures should be maintained during use and disposal of hazardous chemicals. This would ensure that the biotic components of the Nigerian Niger Delta ecosystem are prudently protected. Full article

We investigated the protective effect of gallic acid (GA) against methotrexate (MTX)-induced hepatotoxicity and nephrotoxicity. Male Wistar rats were randomized into five groups (n = 6/group): I, control; II, MTX-treated for seven days; III, pre-treated with GA for seven days, followed by MTX for seven days; IV, co-treated with MTX and GA for seven days and V, GA for seven days. MTX caused a significant increase (P<0.05) in plasma biomarkers of nephrotoxicity (urea, creatinine) and hepatotoxicity (Bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transferase) when compared with control. Furthermore, MTX caused a significant decrease in the activities of hepatic enzymic antioxidants (superoxide dismutase, catalase, glutathione S-transferase) and nonenzymic antioxidants (Vitamin C and glutathione), followed by a significant increase in hepatic malondialdehyde content. However, pretreatment and co-treatment with gallic acid ameliorated the MTX-induced biochemical changes observed. Taken together, GA protected against MTX-induced hepatotoxicity and nephrotoxicity in rats, by reducing the impact of oxidative damage to tissues. Full article

The blue mussel is a filter-feeding bivalve commonly used in ecotoxicological monitoring as a sentinel species. Due to climate change and the increase of temperature expected in marine environment, it is important to anticipate potential impacts on this species. The aim of this study was to investigate the immunocompetence of blue mussels acclimated to different temperatures and on the effects of increasing temperatures (5, 10 and 20°C). Different indices and gonad maturation stages were also determined throughout the experiments. Cell viability, phagocytosis, serum lysozyme activity and cyclooxygenase (COX) activity were evaluated as immune parameters. The cellular immunity was also evaluated after hemocytes exposure to various cadmium concentrations in vitro. The results obtained demonstrate modulation of hemocyte viability and the ability of these cells to phagocytize in absence of contaminants. After the exposure to cadmium, hemocytes showed greater viability at 5°C while maintaining a higher phagocytic competence. In addition, the lysozyme activity stayed stable at all tested temperatures, contrary to that of COX, which increased when the mussels were maintained at 20°C. The evaluation of indices demonstrated no reduction of general conditions during all the experiment despite the increase of temperature and the reduction of the digestive gland weight. Moreover, the lack of food does not affect gonad maturation and the spawning process. Full article