Effect of sodium dodecyl sulfate (SDS) on stress response in the Mediterranean mussel (Mytilus Galloprovincialis): regulatory volume decrease (Rvd) and modulation of biochemical markers related to oxidative stress

Effects of α-olefin sulfonate (AOS) on Tubifex tubifex: toxicodynamic-toxicokinetic inferences from the general unified threshold (GUTS) model, biomarker responses and molecular docking predictions

We investigated the potential ecological risks and harm to aquatic organisms posed by anionic surfactants such as α-olefin sulfonate (AOS), which are commonly found in industrial and consumer products, including detergents. This study assessed acute (96-h) and subchronic (14-day) responses using antioxidant activity, protein levels, and histopathological changes in Tubifex tubifex exposed to different AOS concentrations (10% of the LC50, 20% of the LC50, and a control). Molecular docking was used to investigate the potential interactions between the key stress biomarker enzymes (superoxide dismutase, catalase, and cytochrome c oxidase) of Tubifex tubifex. Acute AOS exposure showed a concentration-dependent decrease in survival, and the general unified threshold (GUTS) model revealed that survivorship is linked to individual response patterns rather than random (stochastic) fluctuations. The GUTS model also revealed dose-dependent toxicity patterns in Tubifex tubifex exposed to α-olefin sulfonate (AOS), with adaptive mechanisms at lower concentrations but significant increases in mortality beyond a certain threshold, emphasizing the role of the AOS concentration in shaping its toxicological impact. Exposure to AOS disrupted antioxidant activity, inducing oxidative stress, with GST and GPx showing positive associations with surfactant concentration and increased lipid peroxidation (elevated MDA levels); moreover, AOS exposure decreased protein concentration, signifying disturbances in vital cellular processes. Histopathological examinations revealed various tissue-level alterations, including cellular vacuolation, cytoplasmic swelling, inflammation, necrosis, and apoptosis. Molecular docking analysis demonstrated interactions between AOS and enzymes (-catalase, superoxide dismutase, and cytochrome c oxidase) in Tubifex tubifex, including hydrophobic and hydrogen bond interactions, with the potential to disrupt enzyme structures and activities, leading to cellular process disruptions, oxidative stress, and tissue damage. According to the species sensitivity distribution (SSD), the difference in toxicity between Tilapia melanopleura (higher sensitivity) and Daphnia magna (low sensitivity) to AOS suggests distinct toxicokinetic and toxicodynamic mechanisms attributable to more complex physiology in Tilapia and efficient detoxification in Daphnia due to its smaller size.

Increasing Risks to the Health of the Invertebrates-Balancing between Harm and Benefit

The article discusses the issue of extensive use of detergents and sanitizers in the time of new challenges associated with the COVID-19 (SARS-CoV-2) pandemic. These agents could pose threats to the existence of free-living invertebrates as essential components of the ecosystem. The biological effects of the mentioned classes of substances, their metabolites, and combined effects in the mixture have not been studied enough. The main challenges in trying to balance the threats and benefits of using such substances are the lack of knowledge of the biological effects of these products, the gaps in testing invertebrates' responses, and changes in environment-related regulations to minimize risks to animals and humans. Numerous studies in this field still leave research gaps, particularly concerning the combined toxicity of well-known and widely used disinfectants, surfactants, and heavy metals, posing potential future challenges. Additionally, the review identified the need for additional testing of invertebrates for their sensitivity to disinfectants and surfactants of different compositions, including improved (non-invasive) methods, studies for early life stages, and comparative studies of species resilience.

Evaluating quaternium-15 effects on Mytilus galloprovincialis: New insights on physiological and cellular responses

Among personal care products, quaternium-15 is prominently featured as a preservative in items such as shampoos, soaps, shaving products, and cosmetics. The widespread use of these products in people's daily routines contributes to quaternium-15 release into aquatic ecosystems. In this context, the primary aim of the study was to assess the physiological and cellular responses of the digestive gland and gills in Mytilus galloprovincialis to quaternium-15 exposure. Cell viability and the ability of digestive gland cells to regulate their volume were evaluated. Additionally, the expression of the genes involved in oxidative stress response was assessed to further substantiate the compound's harmful effects. Results indicated a significant decrease in both the viability of digestive gland cells and their RVD (regulatory volume decrease) capacity when exposed to a hypotonic solution. Furthermore, impairment of digestive gland cell function was corroborated by the modulation of oxidative stress-related gene expression, including SOD, Cat, as well as Hsp70 and CYP4Y1. Similar gene expression alterations were observed in the gills, reflecting impaired functionality in this vital organ as well. In summary, the outcomes of the study provide conclusive evidence of the toxicity of quaternium-15. This underscores the urgent need to further investigate the toxicological effects of this contaminant on aquatic ecosystems and emphasises the necessity of limiting the use of products containing quaternium-15.

Comparative subcellular responses to pharmaceutical exposures in the mussel Mytilus galloprovincialis: An in vitro study

Pharmaceutical active compounds (PhACs) have raised concerns in the last decade due to their increased consumption and inadequate elimination during discharge, resulting in their introduction into water systems and potential significant threats to non-target organisms. However, few studies have investigated the sublethal impacts of PhAC exposure on marine invertebrates. Thus, the present study aimed to assess tissue-specific responses in Mytilus galloprovincialis to sodium lauryl sulfate (SLS), salicylic acid (SA), and caffeine (CAF) (4.0 mg/L, 4.0 mg/L and 2.0 μg/L, respectively). Short-term in vitro exposures with mussel digestive gland and gill tissues were conducted and biochemical responses related to antioxidant and detoxification capacity, cellular damage and neurotoxicity were assessed. The present results clearly showed significant differences in tissue sensitivity and biochemical responses to the contaminants tested. This study highlights the suitability of filter-feeder species as valuable model organisms for studying the sublethal effects of unintended environmental exposures to PhACs.

Immunotoxic effects of exposure to the antifouling copper(I) biocide on target and nontarget bivalve species: a comparative in vitro study between Mytilus galloprovincialis and Ruditapes philippinarum

Edible bivalves constitute an important bioresource from an economic point of view, and studies on their immune responses to environmental pollutants are crucial for both the preservation of biodiversity and economic reasons. The worldwide diffusion of copper(I)-based antifouling paints has increased copper leaching into coastal environments and its potential impact on both target and nontarget organisms. In this study, immunotoxicity assays were carried out with short-term (60 min) cultures of hemocytes from the bivalves Mytilus galloprovincialis-a mussel dominant in the macrofouling community-and Ruditapes philippinarum-a clam dominant in the soft-sediment community-exposed to CuCl to compare the toxic effects on their immune responses. The LC50 values were similar, 40 μM (3.94 mg L-1) for the mussel and 44 μM (4.33 mg L-1) for the clam. In both species, apoptosis occurred after exposure to 1 µM (98.9 μg L-1) CuCl, the concentration able to significantly increase the intracellular Ca2+ content. Biomarkers of cell morphology and motility revealed microfilament disruption, a significant decrease in yeast phagocytosis and lysosome hydrolase (β-glucuronidase) inhibition beginning from 0.5 µM (49.5 μg L-1) CuCl in both the mussel and clam. The same concentration of CuCl affected biomarkers of oxidative stress, as a significant decrease in reduced glutathione content in the cytoplasm and inhibition of mitochondrial cytochrome-c oxidase (COX) were detected in both species. Comparison of the biomarkers showed that clam is more sensitive than the mussel regarding alterations to the lysosomal membrane and reactive oxygen species (ROS) production, which supports the potential harmful effects of antifouling biocides on the survival of nontarget pivotal species in the coastal community.

Toxic effects of sodium dodecyl sulfate on planarian Dugesia japonica

Sodium dodecyl sulfate (SDS) is an anionic surfactant, which is widely used in various fields in human life. However, SDS discharged into the water environment has a certain impact on aquatic organisms. In this study, planarian Dugesia japonica (D. japonica) was used to identify the toxic effects of SDS. A series of SDS solutions with different concentrations were used to treat planarians for the acute toxicity test , and the results showed that the semi-lethal concentration (LC₅₀) of SDS to D. japonica at 24 h, 48 h, 72 h, and 96 h were 4.29 mg/L, 3.76 mg/L, 3.45 mg/L, and 3.20 mg/L respectively. After the planarians were exposed to 0.5 mg/L and 1.0 mg/L SDS solutions for 1, 3, and 5 days, the activities of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) content were measured to detect the oxidative stress and lipid peroxidation in planarians. Random amplified polymorphic DNA (RAPD) analysis was performed to detect the genotoxicity caused by SDS to planarians. The results showed that the activities of SOD, CAT, and MDA content increased after the treatment, indicating that SDS induced oxidative stress in planarians. RAPD analysis showed that the genomic template stability (GTS) values of planarians treated by 0.5 mg/L and 1.0 mg/L SDS for 1, 3, and 5 days were 67.86%, 64.29%, 58.93%, and 64.29%, 60.71%, 48.21%, respectively. GTS values decreased with the increasing of SDS concentration and exposure time, indicating that SDS had genotoxicity to planarians in a time and dose-related manner. Fluorescent quantitative PCR (qPCR) was used to investigate the effects of SDS on gene expression of planarians. After the planarians were exposed to 1.0 mg/L SDS solution for 1, 3, and 5 days, the expression of caspase3 was upregulated, and that of piwiA, piwiB, PCNA, cyclinB, and RAD51 were downregulated. These results suggested that SDS might induce apoptosis, affect cell proliferation, differentiation, and DNA repair ability of planarian cells and cause toxic effects on planarian D. japonica.

Fitness assessment of Mytilus galloprovincialis Lamarck, 1819 after exposure to herbicide metabolite propachlor ESA

The lack of data on the chronic effects of chloroacetanilide herbicide metabolites on non-target aquatic organisms creates a gap in knowledge about the comprehensive impacts of excessive and repeated pesticide use. Therefore, this study evaluates the long-term effects of propachlor ethanolic sulfonic acid (PROP-ESA) after 10 (T1) and 20 (T2) days at the environmental level of 3.5 μg.L^-1 (E1) and its 10x fold multiply 35 μg.L^-1 (E2) on a model organism Mytilus galloprovincialis. To this end, the effects of PROP-ESA usually showed a time- and dose-dependent trend, especially in its amount in soft mussel tissue. The bioconcentration factor increased from T1 to T2 in both exposure groups - from 2.12 to 5.30 in E1 and 2.32 to 5.48 in E2. Biochemical haemolymph profile and haemocyte viability were not affected by PROP-ESA exposure. In addition, the viability of digestive gland (DG) cells decreased only in E2 compared to control and E1 after T1. Moreover, malondialdehyde levels increased in E2 after T1 in gills, and DG, superoxidase dismutase activity and oxidatively modified proteins were not affected by PROP-ESA. Histopathological observation showed several damages to gills (e.g., increased vacuolation, over-production of mucus, loss of cilia) and DG (e.g., growing haemocyte trend infiltrations, alterations of tubules). This study revealed a potential risk of chloroacetanilide herbicide, propachlor, via its primary metabolite in the Bivalve bioindicator species M. galloprovincialis. Furthermore, considering the possibility of the biomagnification effect, the most prominent threat poses the ability of PROP-ESA to be accumulated in edible mussel tissues. Therefore, future research about the toxicity of pesticide metabolites alone or their mixtures is needed to gain comprehensive results about their impacts on living non-target organisms.

Combined effects of temperature rise and sodium lauryl sulfate in the Mediterranean mussel

Personal care products (PCPs) are those compounds used daily (e.g., soaps, shampoos, deodorants, and toothpaste), explaining their frequent detection in aquatic systems. Still, scarce information is available on their effects on inhabiting wildlife. Among the most commonly used PCPs is the surfactant Sodium Lauryl Sulfate (SLS). The present study investigated the influence of temperature (CTL 17 ºC vs 22 ºC) on the effects of SLS (0 mg/L vs 4 mg/L) in the mussel species Mytilus galloprovincialis. Mussels' general health status was investigated, assessing their metabolic and oxidative stress responses. Higher biochemical alterations were observed in SLS-exposed mussels and warming enhanced the impacts, namely in terms of biotransformation capacity and loss of redox homeostasis, which may result in consequences to population maintenance, especially if under additional environmental stressors. These results confirm M. galloprovincialis as an excellent bioindicator of PCPs pollution, and the need to consider actual and predicted climate changes.

Multi-characteristic toxicity of enantioselective chiral fungicide tebuconazole to a model organism Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 (Bivalve: Mytilidae)

The survey of available scientific literature shows a lack of data on the chronic effects of tebuconazole (TEB) on non-target aquatic organisms. Therefore, this study evaluates toxicity (10 and 20 days) of two considered concentrations 2 ng/L (E1) and 2 μg/L (E2) of TEB to bioindicator species Mytilus galloprovincialis. To this end, the TEB concentrations measured in soft mussel tissues showed a time-dependent increasing trend. The viability of haemocyte and digestive gland (DG) cells was higher than 95 % during the experiment. However, DG cells lost the ability to regulate their volume in both groups after 20-d. The E1 treatment increased Cl^- and Na⁺ levels, and E2 decreased Na⁺ levels in the haemolymph. In addition, levels of superoxide dismutase (SOD) activity and oxidatively modified protein (OMP) increased after 10- and 20-d in both treatments. Histopathological findings showed abnormalities in the E2, e.g., haemocyte infiltration, hypertrophy, and hyperplasia in gills and DG. This study reveals the potential risks of TEB usage in the model organism M. galloprovincialis, primarily via bioaccumulation of TEB in food web links, and improves knowledge about its comprehensive toxicity.

Metallic nanoparticles affect uptake of polycyclic aromatic hydrocarbons and impacts in the Mediterranean mussels Mytilus galloprovincialis

The impact of metallic nanoparticles (NPs) on the uptake and toxicity of persistent organic pollutants by marine bivalves was assessed through a comparative laboratory study by exposing mussels to polycyclic aromatic hydrocarbon (PAHs), in the presence and absence of ZnO and TiO₂ NPs. PAHs and NPs concentration was analyzed after 14 days of exposure in mussels by GC/MS and ICP/AES. Furthermore, impact on the physiology and neurotoxicity of PAHs and NPs acting alone or in mixtures were also determined. Our results confirmed the bio-uptake of PAHs and NPs by mussels. In addition, the exposure NPs-PAHs resulted in different bio-uptake profile to that of PAHs alone. The NPs and accumulation of PAHs led to disturbance of essential metals concentration and to different impact profiles in the filtration and respiration capacities as well as in the acetylcholinesterase activity. Antagonist interactions between NPs and PAHs could occur after exposure.

Oxidative stress and behavioral responses of moorish geckos (Tarentola mauritanica) submitted to the presence of an introduced potential predator (Hemorrhois hippocrepis)

Stressful situations induce an increase in the production of reactive oxygen species (ROS) which can lead to molecular damage and alteration of cell function. The introduction of new potential predators induces physiological stress in native fauna. However, behavioral responses have been reported in preys, demonstrating an induction of the defenses against alien species. Behavioral and antioxidant enzyme responses in the moorish gecko, Tarentola mauritanica, against the invasive predator horseshoe whip snake (Hemorrhois hippocrepis) were assessed. Behavior was recorded and a tissue sample from the tail was collected after placing the gecko in a terrarium with previous absence or presence of the snake in 'Control' and 'H. hippocrepis' groups, respectively. Fifteen behavioral variables were examined, including tongue flick (TF) and locomotion patterns. Antioxidant enzyme activities -catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR)-, and the levels of reduced (GSH) and oxidized glutathione (GSSG), glutathione/glutathione disulfide ratio (GSH/GSSG) and malondialdehyde (MDA) concentrations were measured in the tissue sampled. Geckos exposed to the snake's odor showed a higher number of TF, longer amounts of time remaining motionless or moving in slow motion and they spent less time on the ground in comparison to the 'Control' group. The presence of the snake produced a significant increase in the activities of CAT, SOD and GR and a decrease in the GSH/GSSG ratio in T. mauritanica individuals exposed to the snake's scent. Thus, both behavioral responses and oxidative stress biomarkers clearly showed that T. mauritanica is able to recognize H. hippocrepis as a potential predator, despite being a recently introduced snake at the Balearic Islands.

Botrytis cinerea alcohol dehydrogenase mediates fungal development, environmental adaptation and pathogenicity

Botrytis cinerea is an economically critical necrotrophic fungus that infecting many types of plants species. Although the lifestyle adaptations and genetic foundations of several enzymes and metabolites involved in B. cinerea virulence during host plant infection are well studied, the role of B. cinerea alcohol dehydrogenase (ADH) enzymes in these processes is poorly understood. Herein, we identified a significant up-regulation of the transcriptional levels of the BcADH1 gene during the tomato - B. cinerea strain B0510 interaction and at the early stage of infection. Substantially, we used a recent approach for replacement of gene by utilizing homologous recombination to generate knock-out mutants (Δbcadh1) and their effective complementary strains (Δbcadh1/C). A strong difference in the morphology of Δbcadh1 mutants from the wild type (WT) was detected, with respect to the conidiospore, conidial germination, and formation of branches, sporulation and sclerotia. In addition, the Δbcadh1 mutants showed significant differences in their virulence on tomato leaves relative to the WT. Moreover, the Δbcadh1 mutants appeared to have higher sensitivity to oxygen limitation (hypoxia) and reactive oxygen species, and had lost their ability of alcoholic fermentation compared with the WT and complementary strains. These results provide strong evidence for the requirement of the ADH1 gene for fungal development, environmental adaptation and its ability for full pathogenicity.Communicated by Ramaswamy H. Sarma.

Toxic Effects of Sodium Lauryl Sulfate on Antioxidant Defense System and DNA Damage in Fish Primary Hepatocyte Cultures

Synthetic detergents which have a major role in environmental pollution accumulate over time and reach levels that harm nature. The surfactants which are abundantly used as cleaning components are discharged into the Van Lake with the sewage water. These chemicals accumulating in the lake may reach a level that could affect the only fish species of the lake, the Van fish. This study aimed to determine the antioxidant levels of Van fish hepatocyte cell culture medium treated with sodium lauryl sulphate (SLS) and to assess the DNA damage. The effect of SLS was assessed by its dose (1x10−5, 1x10-6, 1x10−7 M) and treatment time (24 h, 48 h). Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and DNA damage (8-OHdG) were determined in the SLS hepatocyte culture. SOD and GSH-Px were higher on 24 h and 48 h compared to the control group. A significant increase was observed in CAT level in the first 24 h, especially in 1x10−6 and 1x10-5 M concentration. At 48 h, it was observed that the CAT level decreased significantly as the concentration increased. It was determined that MDA and 8-OHdG levels increased depending on concentration and time. In conclusion, different concentrations of SLS affected antioxidant levels in the primary hepatocyte culture of Van Fish and were found to cause an increase in the levels of MDA and 8-OHdG.

The physiological, biochemical and transcriptional responses to sulfamethoxazole in the Asian clam, Corbicula fluminea (O. F. Müller, 1774)

Sulfamethoxazole (SMX), a broad-spectrum antibiotic, has been widely used in the treatment and prevention of infection caused by bacteria in recent years. The present study was aimed to evaluate the response mechanisms to SMX stress in gills and digestive gland of Corbicula fluminea (O. F. Müller, 1774). To this end, clams were exposed to environmentally relevant concentrations of SMX (0, 1, 10 and 100 μg/L) for 7 and 28 days, and siphon behavior, tissue-specific enzymatic and transcriptional changes were assayed. Our results showed that exposure to SMX significantly suppressed filtration rate and acetylcholinesterase (AChE) activity, activated antioxidant defense system and elevated transcription of several genes related to cell apoptosis in gills and digestive gland of clams. In general, SMX at environmentally relevant concentrations exhibited a negative impact on siphon behavior and induced neurotoxicology, oxidative stress and cell apoptosis in C. fluminea. The current study will help broaden our understanding of the ecotoxicity of SMX on freshwater bivalves.

Synthetic and biological surfactant effects on freshwater biofilm community composition and metabolic activity

Surfactants are used to control microbial biofilms in industrial and medical settings. Their known toxicity on aquatic biota, and their longevity in the environment, has encouraged research on biodegradable alternatives such as rhamnolipids. While previous research has investigated the effects of biological surfactants on single species biofilms, there remains a lack of information regarding the effects of synthetic and biological surfactants in freshwater ecosystems. We conducted a mesocosm experiment to test how the surfactant sodium dodecyl sulfate (SDS) and the biological surfactant rhamnolipid altered community composition and metabolic activity of freshwater biofilms. Biofilms were cultured in the flumes using lake water from Lake Lunz in Austria, under high (300 ppm) and low (150 ppm) concentrations of either surfactant over a four-week period. Our results show that both surfactants significantly affected microbial diversity. Up to 36% of microbial operational taxonomic units were lost after surfactant exposure. Rhamnolipid exposure also increased the production of the extracellular enzymes, leucine aminopeptidase, and glucosidase, while SDS exposure reduced leucine aminopeptidase and glucosidase. This study demonstrates that exposure of freshwater biofilms to chemical and biological surfactants caused a reduction of microbial diversity and changes in biofilm metabolism, exemplified by shifts in extracellular enzyme activities. KEY POINTS: • Microbial biofilm diversity decreased significantly after surfactant exposure. • Exposure to either surfactant altered extracellular enzyme activity. • Overall metabolic activity was not altered, suggesting functional redundancy.

Effects of three surfactants on the degradation and environmental risk of metolachlor in aquatic environment

Surfactants and pesticides can be simultaneously detected in the environment by the reason of their widespread use and large amounts of emissions. Due to the special amphipathicity of surfactants, it may have special effects on the environmental behaviors and toxic effects of other substances in the environment. There are few relevant studies at present. In this study, the effects of three surfactants on the degradation of the amide pesticide metolachlor in water-sediment system were investigated. The study found that the three surfactants had no significant effect on the degradation of metolachlor in the system at environmental concentrations. However, at critical micelle concentration, cationic surfactant octadecyl trimethyl ammonium bromide and nonionic surfactant nonylphenol polyoxyethylene ether promoted the degradation of metolachlor in water-sediment system. Anionic surfactant odium dodecylbenzene sulfonate (SDBS) prolonged the degradation half-life of metolachlor. The presence of surfactants not only affected the environmental behavior of pesticides. When they coexisted with pesticides, the joint toxicity to aquatic organisms cannot be ignored. This study found that the combined effects of three surfactants and metolachlor on the acute developmental toxicity of zebrafish embryos were all synergistic effects. The combined effects of two ionic surfactants and metolachlor on the acute toxicity of adult zebrafish were synergistic effects. Further study showed that co-exposure of SDBS and metolachlor increased the absorption of metolachlor by zebrafish. Combined exposure of SDBS and metolachlor caused oxidative stress in brain, gill and liver of zebrafish. The results showed that the simultaneous presence of anionic surfactants and pesticides in the environment may increase the environmental risk of pesticides.

Microbial and physicochemical responses of anaerobic hydrogen-producing granular sludge to polyethylene micro(nano)plastics

Micro(nano)plastics is an emerging contaminant in wastewater that has showed significant impacts on various biological treatment processes. Nevertheless, the underlying effects of micro(nano)plastics with different concentrations and sizes on the anaerobic hydrogen-producing granular sludge (HPG) were still unclear. This work firstly attempted to illustrate the microbial and physicochemical responses of HPG to a shock load of polyethylene microplastics (PE-MPs) with varied concentrations and sizes. The results revealed that the PE-MPs inhibitory effect on hydrogen production by HPG was both concentration- and size-dependent. Specifically, the increase of PE-MPs concentration and the decline of PE-MPs size to nano-sized plastics (NPs) significantly decreased the hydrogen yield, downgraded to 79.9 ± 2.6% and 63.0 ± 3.9% (p = 0.001, and 0.0002) of control, respectively, at higher MPs concentration and the smaller MPs size (i.e., NPs). The higher PE-MPs concentration and PE-NPs also suppressed extracellular polymeric substances (EPS) generation more severely. The critical bio-processes involved in hydrogen production were disturbed by PE-MPs, with the extent of negative impacts depending on the dosage and size of PE-MPs. These adverse impacts further manifested as granule disintegration and loss of cellular activity. Mechanism analysis highlighted the roles of oxidative stress, leachate released from PE-MPs, interaction between PE-NPs and granules inducing physical crushing of HPG that led to possible direct contact between cells and toxic substances.

Evaluation of toxicity of Personal Care Products (PCPs) in freshwaters: Zebrafish as a model

Personal care products (PCPs) are part of the large and growing family of emerging contaminants (ECs). Many daily products such as sunscreens, toothpaste, make-up products, perfume, and others, fall under this definition, and their use is increasing exponentially. Furthermore, the degradation of some components of these products is limited. Indeed, they are able to easily reach and accumulate in aquatic systems, representing a new class of contaminants. Moreover, due to their chemical properties, they can interfere at different biological levels, and for this reason, they need to be thoroughly investigated. We have reviewed the literature on PCPs, with a special focus on the adverse effects on the freshwater zebrafish (Danio rerio). The aim of this work is to provide a careful assessment of the toxicity of these compounds, in order to raise awareness for more conscious and responsible use.

Responses of anaerobic hydrogen-producing granules to acute microplastics exposure during biological hydrogen production from wastewater

Anaerobic hydrogen-producing granule (AHPG) has been successfully applied in hydrogen production from wastewater. While various types of microplastics in large amounts are readily detected in both municipal and industrial wastewaters, however, to date the response of AHPG to multiple coexisting microplastics in wastewater is unknown yet. Herein, this study provided a first insight into the acute exposure-response relationship between multiple coexisting microplastics and the AHPG during biological hydrogen production from wastewater. Fluorescence tagging found that many microplastics accumulated and covered on the surface of the whole granule. Morphology and particle size of microplastics-bearing AHPG were characterized by microscopic observation, showing that the shock load of microplastics in the wastewater at the studied concentrations (40 and 80 mg/L) made the granule loose and even break down with the decreased particle size. The visualization of extracellular polymeric substances (EPS) structure revealed that microplastics decreased EPS production by 8.8-16.7%. Microbial community analysis demonstrated that the acute exposure of microplastics did not drive the change in the microbial community diversity and composition. However, toxic leachates and upgraded oxidative stress induced by microplastics increased cell death up to 14.7% and decreased hydrogen production by 18.7%, when the AHPG exposed to 80 mg/L of microplastics. This work gained a new insight into the response of anaerobic microorganisms to coexisting microplastics in the real environment.

Review: Mytilus galloprovincialis: An essential, low-cost model organism for the impact of xenobiotics on oxidative stress and public health

The level of pollution becomes more and more of a pressuring matter for humankind at a worldwide level. Often the focus is on the effects that we can directly and see such as decreased air quality and higher than normal temperatures and weather, but the effects we cannot see are frequently overlooked. For at least the past decade increasing importance has been given towards the effects of pollution of living animals or non-target organisms and plants. For this purpose, one model animal that surfaced is the purpose, one model animal surfaced is Mytilus galloprovincialis. As all mussels, this species is capable of bio-accumulating important quantities of different xenobiotics such as pesticides, paints, medicines, heavy metals, industrial compounds, and even compounds marketed as antioxidants and antivirals. Their toxic effects can be assessed through their impact on oxidative stress, lysosomal membrane stability, and cell viability through trypan blue exclusion test and neutral red retention assay techniques. The purpose of this paper is to highlight the benefits of using M. galloprovincialis as an animal model for toxicological assays of various classes of xenobiotics by bringing to light the studies that have approached the matter.

Whole-cell electric sensor for determination of sodium dodecyl sulfate

Linear alkyl sulfates are a major class of surfactants that have large-scale industrial application and thus wide environmental release. These organic pollutants threaten aquatic environments and other environmental compartments. We show the promise of the use of a whole-cell electric sensor in the analysis of low or residual concentrations of sodium dodecyl sulfate (SDS) in aqueous solutions. On the basis of bioinformatic analysis and alkylsulfatase activity determinations, we chose the gram-negative bacterium Herbaspirillum lusitanum, strain P6–12, as the sensing element. Strain P6–12 could utilize 0.01–400 mg/L of SDS as a growth substrate. The electric polarizability of cell suspensions changed at all frequencies used (50–3000 kHz). The determination limit of 0.01 mg/L is much lower than the official requirements for the content of SDS in potable and process water (0.5 and 1.0 mg/L, respectively), and the analysis takes about 1–5 min. The promise of H. lusitanum P6–12 for use in the remediation of SDS-polluted soils is discussed.

Behavioral, physiological and biochemical responses and differential gene expression in Mytilus galloprovincialis exposed to 17 alpha-ethinylestradiol and sodium lauryl sulfate

Mixture of contaminants often determine biological responses of marine species, making difficult the interpretation of toxicological data. The pharmaceutical 17 alpha-ethinylestradiol (EE2) and the surfactant Sodium Lauryl Sulfate (SLS) commonly co-occur in the marine environment. This study evaluated the effects of EE2 (125.0 ng/L) and SLS (4 mg/L), acting individually and combined, in the mussel Mytilus galloprovincialis. Contaminated mussels closed their valves for longer periods than control ones, especially in the presence of both contaminants, with longer closure periods immediately after spiking compared to values obtained one day after spiking. Nevertheless, males and females increased their metabolism when in the presence of both contaminants (males) and SLS (females), and independently on the treatment males and females were able to activate their antioxidant and biotransformation defences. Although enhancing defences mussels still presented cellular damage and loss of redox balance, especially noticed in the presence of EE2 for males and SLS for females. Histopathological damage was found at mussel's gills in single and mixture exposure, and qPCR analysis revealed a clear estrogen receptor expression with no additive effect due to combined stressors. The results obtained highlight the harmful capacity of both contaminants but further research on this matter is needed, namely considering different climate change scenarios.

Spatiotemporal Organic Carbon Distribution in the Capo Peloro Lagoon (Sicily, Italy) in Relation to Environmentally Sustainable Approaches

Transitional water environments represent very ecologically interesting areas, which provide various ecosystem services, both concerning biodiversity protection and sustainable fruition of resources. In this way, the evaluation of total carbon and its components, chlorophyll, and chemical and physical parameters is of fundamental importance to deepen the dynamics of these peculiar natural areas. Commercial interests linked to the biological resources of these areas are often not well exploited in relation to their sustainability, due to lack of knowledge. In this study, we investigated the distribution of total organic carbon, chlorophyll, and other related physical and chemical parameters in the natural Lagoon of Capo Peloro (Eastern Sicily), to deepen the knowledge on the carbon equilibrium of these transitional basins. Collected data showed different trends for all parameters, mainly related to different seasons and water exchanges with sea. The influences of primary production sources and farmed molluscs were not negligible and deserve to be further investigated in the future. The results obtained reveal good margins for the possibility of environmentally sustainable exploitation of natural resources in both basins, but at the same time, there is a need for a more detailed knowledge of anthropogenic impacts on the area.

Effect of sodium dodecylbenzene sulfonate on hydrogen production from dark fermentation of waste activated sludge

Sodium dodecylbenzene sulfonate (SDBS), a typical surfactant being widely used in various applications, was highly accumulated in waste activated sludge. To date, however, its effect on hydrogen production from dark fermentation of sludge has not been documented. The work therefore aimed to explore whether and how SDBS affects hydrogen production. Experimental results showed that with an increase of SDBS from 0 to 30 mg/g TSS, the maximal hydrogen yield increased from 2.47 to 10.73 mL/g VSS (without any treatment) and from 13.05 to 23.51 mL/g VSS (under free ammonia pretreatment). Mechanism exploration showed that SDBS lowered surface tension, facilitated organics transfer from solid to liquid. SDBS also destroyed hydrogen bonding networks of protein, promoted macromolecular organics degradation. Besides, SDBS improved the electric charge in organics, then weakened the mutual repulsion, improved adsorb, interact and promoted the availability of reaction sites between anaerobes and organic substances. Enzyme activity analysis showed that SDBS not only improved the activities of enzymes related to hydrolysis and acidification processes, but also inhibited the activities of homoacetogens and methanogens. SDBS presence lowered sludge ORP and created an environment which was helpful to the growth of butyric-type bacteria, thus enhanced butyric-type fermentation, which contributed hydrogen production largely. Microbial community analysis revealed that SDBS existence affected distributions of microbial populations, and increased the abundances of hydrogen producing microorganisms (e.g., unclassified_f_Synergistaceae). PICRUSt2 analysis showed that SDBS reduced hydrogenotrophic methanogens activity for its inhibitory effect on the biotransformation of 5,10-Methenyl-THMPT to 5-methyl-THMPT.

Effects of long-term exposure of Mytilus galloprovincialis to thiacloprid: A multibiomarker approach

Thiacloprid is a neonicotinoid insecticide widely exploited in agriculture and easily mobilized towards aquatic environments by atmospheric agents. However, little information about its toxicological effects on aquatic invertebrate bioindicators is available. In this study, specimens of the mussel Mytilus galloprovincialis were exposed to thiacloprid at environmental (4.5 μg L^-1) and 100 times higher than environmental (450 μg L^-1) concentrations for 20 days. Thiacloprid affected haemolymph biochemical parameters, cell viability in the digestive gland, antioxidant biomarkers and lipid peroxidation in the digestive gland and gills at environmentally relevant concentrations (4.5 μg L^-1). In addition, thiacloprid exposure caused histological damage to the digestive gland and gills. Interestingly, the pesticide was detected at levels equal to 0.14 ng g^-1 in the soft tissues of sentinels exposed for 20 days to 450 μg L^-1 thiacloprid in seawaterμ. Due to its harmful potential and cumulative effects after long-term exposure of M. galloprovincialis, thiacloprid may pose a potential risk to nontarget aquatic organisms, as well as to human health. This aspect requires further in-depth investigation.

Development of a Cell-Based Biosensor for Residual Detergent Detection in Decellularized Scaffolds

Ex vivo engineering of organs that uses decellularized whole organs as a scaffold with autologous stem cells is a potential alternative to traditional transplantation. However, one of the main challenges in this approach is preparing cytocompatible scaffolds. So far, high-precision and specific evaluation methods have not been developed for this purpose. Cell-based biosensors (CBBs) are promising tools to measure analytes with high sensitivity and specificity in a cost-effective and noninvasive manner. In this paper, using the NF-κB inducible promoter we developed a CBB for residual detergent detection. Proximal and core sections of the inducible promoter, containing NF-κB binding sequence, are designed and cloned upstream of the reporter gene (secreted alkaline phosphatase (SEAP)). After transfection into HEK293 cells, stable and reliable clones were selected. After confirmation of induction of this gene construct by sodium dodecyl sulfate (SDS), the stability and function of cells treated by qPCR and SEAP activity were measured. This biosensor was also used to evaluate the cytocompatibility of decellularized tissue. Results showed that the developed biosensor could detect very small amounts of SDS detergent (3.467 pM). It has the best performance 8 h after exposure to detergent, and its stability in high passage numbers was not significantly reduced. Applying this biosensor on decellularized tissues showed that SEAP activity higher than 4.36 (U/L) would lead to a viability reduction of transplanted cells below 70%. This paper presents a novel method to evaluate the cytocompatibility of decellularized tissues. The developed CBB can detect residual detergents (such as SDS) in tissues with high sensitivity and efficiency.

The influence of salinity on sodium lauryl sulfate toxicity in Mytilus galloprovincialis

The influence of salinity on the effects of sodium lauryl sulfate (SLS) was evaluated using the Mediterranean mussel Mytilus galloprovincialis, exposed for 28 days to SLS (control-0.0 and 4.0 mg/L) under three salinity levels (Control-30, 25 and 35). The effects were monitored using biomarkers related to metabolism and energy reserves, defence mechanisms (antioxidant and biotransformation enzymes) and cellular damage. The results revealed that non-contaminated mussels tended to maintain their metabolic capacity regardless of salinity, without activation of antioxidant defence strategies. On the contrary, although contaminated mussels presented decreased metabolic capacity at salinities 25 and 35, they were able to activate their antioxidant mechanisms, preventing cellular damage. Overall, the present findings indicate that SLS, especially under stressful salinity levels, might potentially jeopardize population survival and reproduction success since reduced metabolism and alterations on mussels' antioxidant mechanisms will impair their biochemical and, consequently, physiological performance.

Developmental toxicity, antioxidant, and marker enzyme assessment of swertiamarin in zebrafish (Danio rerio)

A secoiridoid glycoside called swertiamarin has been widely used as a herbal medicine for many decades. In particular, swertiamarin from the Enicostema axillare herb has been used as a multipurpose drug to treat innumerable health problems. As this medicine is consumed orally, its toxicity level should be determined. To examine the safety of this compound, toxicology work was done in zebrafish, and this is the first report to describe swertiamarin toxicity in zebrafish. Zebrafish embryos were used in this swertiamarin toxicity study, and morphological changes were observed. Further, the compound was also studied in adult zebrafish to determine the impact of the compound on the fish liver. Enzyme profiling with superoxide dismutase, glutathione peroxidase, catalase, reduced glutathione levels, glutathione S-transferase, lactate dehydrogenase, glutamic oxaloacetic transaminases, lipid peroxidation, Na⁺ /K⁺ -ATPase, and glutamic pyruvic transaminases) was evaluated (p ≤ 0.05). Results suggest that swertiamarin is a safe drug only at a low concentration (40 µM). This study also shows that even herbal medicinal compounds may be toxic to humans at higher dosages. Hence, irrespective of whether a drug is synthetic or natural, it needs to be tested for its toxicity before use in humans.

Evolutionary, genomic, and biogeographic characterization of two novel xenobiotics-degrading strains affiliated with Dechloromonas

Xenobiotics are generally known as man-made refractory organic pollutants widely distributed in various environments. For exploring the bioremediation possibility of xenobiotics, two novel xenobiotics-degrading strains affiliated with Azonexaceae were isolated. We report here the phylogenetics, genome, and geo-distribution of a novel and ubiquitous Azonexaceae species that primarily joins in the cometabolic process of some xenobiotics in natural communities. Strains s22 and t15 could be proposed as a novel species within Dechloromonas based on genomic and multi-phylogenetic analysis. Pan-genome analysis showed that the 63 core genes in Dechloromonas include genes for dozens of metabolisms such as nitrogen fixation protein (nifU), nitrogen regulatory protein (glnK), dCTP deaminase, C4-dicarboxylate transporter, and fructose-bisphosphate aldolase. Strains s22 and t15 have the ability to metabolize nitrogen, including nitrogen fixation, NirS-dependent denitrification, and dissimilatory nitrate reduction. Moreover, the novel species possesses the EnvZ-OmpR two-component system for controlling osmotic stress and QseC-QseB system for quorum sensing to rapidly sense environmental changes. It is intriguing that this new species has a series of genes for the biodegradation of some xenobiotics such as azathioprine, 6-Mercaptopurine, trinitrotoluene, chloroalkane, and chloroalkene. Specifically, glutathione S-transferase (GST) and 4-oxalocrotonate tautomerase (praC) in this novel species play important roles in the detoxification metabolism of some xenobiotics like dioxin, trichloroethene, chloroacetyl chloride, benzo[a]pyrene, and aflatoxin B1. Using data from GenBank, DDBJ and EMBL databases, we also demonstrated that members of this novel species were found globally in plants (e.g. rice), guts (e.g. insect), pristine and contaminated regions. Given these data, Dechloromonas sp. strains s22 and t15 take part in the biodegradation of some xenobiotics through key enzymes.

The potential of microplastics as adsorbents of sodium dodecyl benzene sulfonate and chromium in an aqueous environment

Considering the omnipresence of microplastics (MPs) in aquatic environments, they are expected to exert significatn impacts as carriers for diverse waterborne pollutants. In this work, the adsorptive behavior of two ionic components (i.e., sodium dodecyl benzene sulfonate (SDBS) and Cr(VI)) has been explored against the two types of MPs as model adsorbents, namely poly (ethylene terephthalate) (PET) and polystyrene (PS). The influence of key variables (e.g., pH, particle size, and dose of the MPs) on their adsorption behavior is evaluated from various respects. The maximum adsorption capacity values of SDBS on PET and PS are estimated to be 4.80 and 4.65 mg⋅g^-1, respectively, while those of Cr(VI) ions are significantly lower at 0.080 and 0.072 mg⋅g^-1, respectively, The adsorptive equilibrium of SDBS is best described in relation to pH and MP size by a Freundlich isotherm. In contrast, the adsorption behavior of Cr(VI) is best accounted for by a Langmuir isotherm to indicate its adsorption across at least two active surface sites.

Testing the response of benthic diatom assemblages to common riverine contaminants

Benthic diatoms constitute keystone assemblages in riverine ecosystems, and their structure is used to support regulatory water quality assessment. However, no standard ecotoxicological tests exist using integrated responses of the benthic diatom assemblages. This work aimed to assess whether benthic diatom assemblages are responsive to different riverine contaminants through a previously developed rapid toxicity test, supporting future attempts towards its standardization and integration in both prospective and retrospective Environmental Risk Assessment (ERA) schemes. We selected two benthic diatoms assemblages likely responding similarly to pollution (similar IPS diatom index score), collected from two rivers in Northern-Central Portugal (sites: Palhal and Cabreia). Fresh whole diatom assemblages were exposed for 48 h to five model contaminants (glyphosate, imidacloprid, SDS, CuSO₄, and Pb). At the end of the test, changes induced by the exposures in overall yield and in the yield of each diatom genus were assessed. The assemblage collected at Palhal was invariably more responsive and sensitive than that collected at Cabreia, both considering overall and genus-specific yields, regardless of the tested contaminant. Achnanthes, Fragilaria and Navicula were the most responsive genus, regardless of the tested contaminant or assemblage. The distinct response profiles observed for the two assemblages to the same contaminants at the same concentration ranges suggest that using this test method to support prospective ERA is inadequate. However, the method can be an asset supporting retrospective ERA, as the responses seem to be shaped by the interplay of resilience drivers promoted by the local conditions, e.g. adaptive changes in assemblage structure.

The formation and antibacterial activity of Zn/ZnO nanoparticle produced in Pometia pinnata leaf extract solution using a laser ablation technique

The single-step green synthesis has been successfully established to prepare a bi-phase structure of Zn/ZnO nanoparticles using laser ablation in a liquid medium. Nd: YAG laser with the wavelength of 1064 nm was employed to perform the laser ablation in pure water and Pometia pinnata (P. pinnata) leaf extract, with the leaf, were extracted in pure water and some concentration of ethanol. ZnO nanoparticles can be obtained via laser ablation in pure water, while the usage of P. pinnata leaf extract as the solution has caused the appearance of the bi-phase Zn/ZnO nanostructure. X-ray diffraction (XRD) pattern indicates the appearance of Zn peaks alongside with ZnO peaks with the inclusion of P. pinnata leaf extract. Transmission electron microscope (TEM) images show the change of shape from the rod-like shape into a spherical shape and smaller size spherical shape of Zn/ZnO nanoparticles in comparison with ZnO. Noticeable change of UV-visible spectrum emerges as the water was substituted by P. pinnata leaf extract. The zeta potential of Zn/ZnO prepared with P. pinnata extracted in water, with the value of - 18.9 V, reduces down to - 43.5 and - 41.1 for 20-40% of ethanol concentration, respectively. The as-prepared ZnO and Zn/ZnO colloidal samples were evaluated for their antibacterial activities against two strains Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Zn/ZnO sample shows a more substantial antibacterial effect in comparison with pure ZnO, no bacteria alive after 12 and 24 h' treatment for E. coli and S. aureus, respectively.

Sperm quality assessment in Ficopomatus enigmaticus (Fauvel, 1923): Effects of selected organic and inorganic chemicals across salinity levels

Contamination by organic and inorganic compounds remains one of the most complex problems in both brackish and marine environments, causing potential implications for the reproductive success and survival of several broadcast spawners. Ficopomatus enigmaticus is a tubeworm polychaete that has previously been used as a model organism for ecotoxicological analysis, due to its sensitivity and ecological relevance. In the present study, the effects of five trace elements (zinc, copper, cadmium, arsenic and lead), one surfactant (sodium dodecyl sulfate, SDS) and one polycyclic aromatic hydrocarbon (benzo(a)pyrene, B(a)P) on the sperm quality of F. enigmaticus were investigated. Sperm suspensions were exposed in vitro to different concentrations of each selected contaminant under four salinity conditions (10, 20, 30, 35). Possible adverse effects on sperm function were assessed by measuring oxidative stress, membrane integrity, viability and DNA damage. Sperm quality impairments induced by organic contaminants were more evident than those induced by inorganic compounds. SDS exerted the largest effect on sperm. In addition, F. enigmaticus sperm showed high tolerance to salinity variation, supporting the wide use of this species as a promising model organism for ecotoxicological assays. Easy and rapid methods on polychaete spermatozoids were shown to be effective as integrated sperm quality parameters or as an alternative analysis for early assessment of marine and brackish water pollution.

eIF3k Domain-Containing Protein Regulates Conidiogenesis, Appressorium Turgor, Virulence, Stress Tolerance, and Physiological and Pathogenic Development of Magnaporthe oryzae Oryzae

The eukaryotic translation initiation factor 3 (eIF3) complex consists of essential and non-essential sub-complexes. Non-essential eIF3 complex subunits, such as eIF3e, eIF3j, eIF3k, and eIF3l, modulate stress tolerance and enhance the lifespan of Neurospora crassa and Caenorhabditis elegans. However, there is limited knowledge of the role of the non-essential eIF3 sub-complex in the pathophysiological development of plant fungal pathogens. Here, we deployed genetic and biochemical techniques to explore the influence of a hypothetical protein containing eIF3k domain in Magnaporthe oryzae Oryzae (MoOeIF3k) on reproduction, hyphae morphogenesis, stress tolerance, and pathogenesis. Also, the targeted disruption of MoOeIF3k suppressed vegetative growth and asexual sporulation in ΔMoOeif3k strains significantly. We demonstrated that MoOeIF3k promotes the initiation and development of the rice blast disease by positively regulating the mobilization and degradation of glycogen, appressorium integrity, host penetration, and colonization during host-pathogen interaction. For the first time, we demonstrated that the eIF3k subunit supports the survival of the blast fungus by suppressing vegetative growth and possibly regulating the conversions and utilization of stored cellular energy reserves under starvation conditions. We also observed that the deletion of MoOeIF3k accelerated ribosomal RNA (rRNA) generation in the ΔMoOeif3k strains with a corresponding increase in total protein output. In summary, this study unravels the pathophysiological significance of eIF3k filamentous fungi. The findings also underscored the need to systematically evaluate the individual subunits of the non-essential eIF3 sub-complex during host-pathogen interaction. Further studies are required to unravel the influence of synergetic coordination between translation and transcriptional regulatory machinery on the pathogenesis of filamentous fungi pathogens.

Effect of sodium dodecyl sulfate on the production of L-isoleucine by the fermentation of Corynebacterium glutamicum

Corynebacterium glutamicum is a safe and popular industrial microorganism that it is gram-positive bacteria with thick cell walls, which hinder the extracellular secretion of products. Surfactant has good surface or interface activity and can destroy the cell membrane of microorganisms. In this study, the surfactant SDS was used to artificially destroy the cell membrane of Corynebacterium glutamicum, increase the permeability of the cell membrane, and increase the ability of the strain to secrete L-isoleucine. This is the first time that surfactants have been applied to the fermentation of Corynebacterium glutamicum. Results indicated that after optimization, the output of L-isoleucine reached 43.67 g/L, which was 13.01% higher than that without sodium dodecyl sulfate. The yield of the by-products, such as valine, leucine, and alanine, was reduced by 72.30%, 64.30%, 71.70%, respectively. This method can promote the production of L-isoleucine while minimizing the damage of SDS to the strain.

Impacts of salicylic acid in Mytilus galloprovincialis exposed to warming conditions

While many studies have been conducted on drug-inducing alterations in the aquatic environment, little is known about their interaction with climate change, such as rising temperatures. To increase knowledge on this topic, Mytilus galloprovincialis mussels were exposed to two different temperatures 17 ± 1 °C (control) and 21 ± 1 °C in the absence and presence of salicylic acid (SA) (4 mg/L) for 28 days. Salicylic acid in the water and tissues was measured and its impact reported through biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen (GLY), protein (PROT) and lipids (LIP) contents), oxidative stress markers (activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), glutathione balance between the reduced and the oxidized forms (GSH/GSSG), and damage to membrane lipids (lipid peroxidation - LPO). The mussels responded differently if the stresses imposed were single or combined, with greater impacts when both stressors were acting together. Contaminated mussels exposed to high temperatures were unable to increase their metabolic capacity to restore their defence mechanisms, reducing the expenditure of LIP. In the presence of SA and increased temperature antioxidant defences respond differently, with higher SOD levels and inhibition of CAT. The present study highlights not only the negative impact of warming and SA, but especially how temperature increase will promote the impact of SA in M. galloprovincialis, which under predicted climate change scenarios may greatly impair population maintenance and ecosystem biodiversity.

Polystyrene nanoplastics reshape the anaerobic granular sludge for recovering methane from wastewater

Wastewater has been identified as an important carrier for nanoplastics, which could elicit unintended impacts on critical microbial processes. However, the long-term impacts of nanoplastics on anaerobic granular sludge (AGS) for methane recovery from wastewater and the mechanisms involved remains unclear. In this study, we investigated the long term exposure-response relationship between polystyrene nanoplastics (Nano-PS) and AGS. In continuous test over 120 days with 86 days' Nano-PS exposure, feeding wastewater with 10 μg/L of Nano-PS had no significant impacts on the AGS performance. In comparison, higher levels (i.e., 20 and 50 μg/L) of Nano-PS decreased methane production and chemical oxygen demand (COD) removal by 19.0-28.6% and 19.3-30.0%, respectively, along with volatile fatty acids (VFA) accumulation. More extracellular polymeric substance (EPS) was induced by 10 μg/L of Nano-PS as a response to protect microbes, but higher levels (i.e., 20 and 50 μg/L) of Nano-PS decreased EPS generation, causing a decline in granule size and cell viability. Fluorescence tagging found that a large number of Nano-PS agglomerated/accumulated on the outer layer of AGS and even transferred into deeper layers of AGS over exposure time, producing toxic effects to adherent microorganisms, e.g., Longilinea sp., Paludibacter sp. and Methanosaeta sp.. The oxidative stress induced by Nano-PS was revealed to be a key factor for reshaping the AGS, reflected by the increased reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) release. The sodium dodecyl sulfate (SDS) leached from Nano-PS was also demonstrated to restrain the activities of antioxidant enzymes, thereby further lessening resistance to oxidative stress induced by Nano-PS. This work improves our ability to predict the risks associated with this ubiquitous contaminant in the environment.

Biochemical markers for prolongation of the acute stress of triclosan in the early life stages of four food fishes

In the present study, embryos of four food fishes viz. Cyprinus carpio, Ctenopharyngodon idella, Labeo rohita and Cirrhinus mrigala were given acute (96 h) exposure to their respective LC₀, LC₁₀ and LC₃₀ (causing 0, 10 and 30% mortality, respectively) concentrations of triclosan [TCS, 5-chloro-2-(2,4-dichlorophenoxy) phenol], a broad spectrum biocide. Bioaccumulation, contents of protein, non-enzymatic antioxidants (GSH and GSSG), MDA (lipid peroxidation product) and organic acids (fumarate, succinate, malate and citrate) along with the activities of AChE (neurological enzyme), GST (detoxification enzyme) and three metabolic enzymes (LDH, AST and ALT) were estimated after 48 and 96 h exposure and 10 days post exposure. Around 1/10 of the TCS in water got accumulated in the hatchlings after 96 h, increase over 48 h values was maximum at LC₀ (+195.30, +143.23 and + 140.75%) but minimum at LC₃₀ (+89.62, +84.26 and + 126.72%) for C. idella, L. rohita and C. mrigala, respectively. In C. carpio, TCS got accumulated only at LC₃₀ after 48 h but at all the concentrations after 96 h exposure. Contents of protein, GSH, GSSG and activity of AChE decreased but activities of GSH, LDH, AST and ALT and contents of MDA and organic acids increased concentration dependently in all the fishes. TCS declined by 85-90% but its toxic effects on biomolecules prolonged till the end of the recovery period. Such acute exposures are accidental but there is a need to evaluate biomarkers for prolongation of the stress of small concentrations especially LC₀ and LC₁₀ (causing negligible mortality) of lipophilic pollutants like TCS.

Gametogenesis-Related Fluctuations in Ovothiol Levels in the Mantle of Mussels from Different Estuaries: Fighting Oxidative Stress for Spawning in Polluted Waters

Reactive oxygen species present a challenge for marine organisms releasing gametes into the water. Thiol-containing molecules protect cells against oxidative stress, and ovothiol (OSH), an antioxidant-reducing mercaptohistidine, has been described as especially relevant in the oocytes of marine invertebrates. Ovothiol synthase (ovoA), in charge of the first step in OSH synthesis, was sequenced in mussels, Mytilus galloprovincialis. Transcription levels of ovoA in mantle did not significantly change along the reproductive cycle. No alterations of ovoA transcription were observed after a laboratory copper (10 µg/L) exposure or in mussels captured in a highly polluted site. Conversely, the metabolomic analysis of the hydrophilic metabolite content in mantle clearly classified mussels according to their site of origin, especially at the most advanced stages of oogenesis. Quantification of OSH-A and -B and glutathione (GSH), revealed stable levels in mantle at early gametogenesis in the unpolluted sampling site, but a strong increase in female mantle previous to spawning in the polluted site. These increased concentrations under pollution suggest that OSH-A accumulates along oogenesis, independent of gene transcription regulation. The concerted accumulation of OSH-A and GSH suggests the building of a balanced cellular redox-system to scavenge ROS produced in the oocyte before and during fertilization.

Lipidomics analysis of juveniles' blue mussels (Mytilus edulis L. 1758), a key economic and ecological species

Blue mussels (Mytilus edulis L. 1758) are important components of coastal ecosystems and in the economy of rural and coastal areas. The understanding of their physiological processes at key life stages is important both within food production systems and in the management of wild populations. Lipids are crucial molecules for bivalve growth, but their diversity and roles have not been fully characterised. In this study, traditional lipid profiling techniques, such as fatty acid (FA) and lipid class analysis, are combined to untargeted lipidomics to elucidate the lipid metabolism in newly settled spat fed on a range of diets. The evaluated diets included single strains treatments (Cylindrotheca fusiformis CCAP 1017/2 -CYL, Isochrysis galbana CCAP 927/1- ISO, Monodopsis subterranean CCAP 848/1 -MONO, Nannochloropsis oceanica CCAP 849/10- NANNO) and a commercial algae paste (SP). Spat growth was influenced by the diets, which, according to their efficacy were ranked as follows: ISO>NANNO/CYL>SP>MONO. A higher triacylglycerols (TG) content, ranging from 4.23±0.82 μg mgashfree Dry weight (DW)-1 at the beginning of the trial (T0) to 51±15.3 μg mgashfreeDW-1 in ISO, characterised significant growth in the spat, whereas, a reduction of TG (0.3±0.08 μg mgashfreeDW-1 in MONO), mono unsaturated FA-MUFA (from 8.52±1.02 μg mgFAashfreeDW-1 at T0 to 2.81±1.02 μg mgFAashfreeDW-1 in MONO) and polyunsaturated FA-PUFA (from 17.57±2.24 μg mgFAashfreeDW-1 at T0 to 6.19±2.49 μg mgFAashfreeDW-1 in MONO) content characterised poor performing groups. Untargeted lipidomics evidenced how the availability of dietary essential PUFA did not influence only neutral lipids but also the membrane lipids, with changes in lipid molecular species in relation to the essential PUFA provided via the diet. Such changes have the potential to affect spat production cycle and their ability to respond to the surrounding environment. This study evidenced the advantages of coupling different lipid analysis techniques, as each technique disclosed relevant information on nutritional requirements of M. edulis juveniles, expanding the existing knowledge on the physiology of this important species.

Genome-wide identification for genes involved in sodium dodecyl sulfate toxicity in Saccharomyces cerevisiae

Background

Sodium dodecyl sulfate (SDS) is one of the most widely used anionic alkyl sulfate surfactants. Toxicological information on SDS is accumulating, however, mechanisms of SDS toxicity regulation remain poorly understood. In this study, the relationship between the SDS-sensitive mutants and their intracellular ROS levels has been investigated.

Results

Through a genome-scale screen, we have identified 108 yeast single-gene deletion mutants that are sensitive to 0.03% SDS. These genes were predominantly related to the cellular processes of metabolism, cell cycle and DNA processing, cellular transport, transport facilities and transport routes, transcription and the protein with binding function or cofactor requirement (structural or catalytic). Measurement of the intracellular ROS (reactive oxygen species) levels of these SDS-sensitive mutants showed that about 79% of SDS-sensitive mutants accumulated significantly higher intracellular ROS levels than the wild-type cells under SDS stress. Moreover, SDS could generate oxidative damage and up-regulate several antioxidant defenses genes, and some of the SDS-sensitive genes were involved in this process.

Conclusion

This study provides insight on yeast genes involved in SDS tolerance and the elevated intracellular ROS caused by SDS stress, which is a potential way to understand the detoxification mechanisms of SDS by yeast cells.

Impact of curcumin on replicative and chronological aging in the Saccharomyces cerevisiae yeast

Curcumin is a biologically active compound of vegetable origin which has a hormetic effect. Pro-health and anti-aging properties of curcumin have been known for years. The main benefit of curcumin is thought to be its anti-oxidative action. Despite vast amount of data confirming age-delaying activity of curcumin in various groups of organisms, so far little has been discovered about curcumin's impact on cell aging in the experimental model of the Saccharomyces cerevisiae budding yeast. We have been able to demonstrate that curcumin significantly increases oxidative stress and accelerates replicative and chronological aging of yeast cells devoid of anti-oxidative protection (with SOD1 and SOD2 gene deletion) and deprived of DNA repair mechanisms (RAD52). Interestingly, curcumin delays aging, probably through hormesis, of the wild-type strain BY4741.

Honey Bee Pollen in Meagre (Argyrosomus regius) Juvenile Diets: Effects on Growth, Diet Digestibility, Intestinal Traits, and Biochemical Markers Related to Health and Stress

This research aimed to evaluate the effects of the inclusion of honey bee pollen (HBP) in meagre (Argyrosoumus regius) juveniles' diets on growth performance, diet digestibility, intestinal morphology, and immunohistochemistry. Furthermore, stress-related molecular markers and biochemical blood profile of fish were evaluated, together with mineral trace and toxic element concentration in pollen and diets. Specimens of meagre (360) of 3.34 ± 0.14 g initial body weight, were randomly allocated to twelve 500 L circular tanks (30 fish per tank). Four diets were formulated: a control diet and three experimental diets with 1%, 2.5%, and 4% of HBP inclusion. All the growth parameters and crude protein and ether extract digestibility coefficients were negatively linearly affected by increased HBP inclusion (p < 0.0001). Histology of medium intestine showed slight signs of alterations in group HPB1 and HPB2.5 compared to control. Fish from HBP4 group showed severe alterations at the intestinal mucosa level. Immunohistochemical detection of TNF-α in the medium intestine showed the presence of TNF-α+ cells in the lamina propria, which resulted in accordance with the increased level of the TNF-α protein detected by immunoblotting in the liver. This stress situation was confirmed by the increased hepatic level of HSP70 (p < 0.05) in fish fed the HBP4 diet and by the linear decrease of total serum protein levels in HBP-containing diets (p < 0.0001). These negative effects can be related to the ultrastructure of the bee pollen grain walls, which make the bioactive substances unavailable and can irritate the intestine of a carnivorous fish such as meagre.

Assessing the effects of neonicotinoid insecticide on the bivalve mollusc Mytilus galloprovincialis

In the present work, the marine invertebrate Mytilus galloprovincialis was used as model organism to evaluate the toxic effects of the neonicotinoid Calypso 480 SC (CAL) following 20 days of exposure to sub-lethal concentrations of 7.77 mg L^-1 (0.1% 96 h-LC50) and 77.70 mg L^-1 (1% 96 h-LC50), and a recovery period of 10 days in uncontaminated seawater. Results revealed that exposure to both concentrations of CAL increased significantly mortality rate in the cells of haemolymph and digestive gland, while digestive gland cells were no longer able to regulate cell volume. Exposure significantly reduced haemolymph parameters (Cl^-, Na⁺), affected the enzymatic activities of superoxide dismutase of digestive gland and catalase of gill, and caused also histopathological alterations in digestive gland and gills. Main histological damages detected in mussels were lipofuscin accumulation, focal points of necrosis, mucous overproduction and infiltrative inflammations. Interestingly, alterations persisted after the recovery period in CAL-free water, especially for haemocyte parameters (K⁺, Na⁺, Ca²⁺, lactate dehydrogenase, glucose). A slight recovery of histological conditions was detected. These findings suggested that sub-chronic exposure to the neonicotinoid insecticide caused significant alterations in both cell and tissue parameters of M. galloprovincialis. Considering the ecologically and commercially important role of mussels in coastal waters, a potential risk posed by neonicotinoids to this essential aquatic resource can be highlighted.

Toxic impacts induced by Sodium lauryl sulfate in Mytilus galloprovincialis

Pharmaceuticals and personal care products (PPCPs) are continuously dispersed into the environment, as a result of human and veterinary use, reaching aquatic coastal systems and inhabiting organisms. However, information regarding to toxic effects of these compounds towards marine invertebrates is still scarce, especially in what regards to metabolic capacity and oxidative status alterations induced in bivalves after chronic exposure. In the present study, the toxic impacts of Sodium lauryl sulfate (SLS), an anionic surfactant widely used as an emulsifying cleaning agent in household and cosmetics, were evaluated in the mussel Mytilus galloprovincialis, after exposure for 28 days to different concentrations (0.0; 0.5; 1.0; 2.0 and 4.0 mg/L). For this, effects on mussels respitation rate, metabolic capacity and oxidative status were evaluated. The obtained results indicate a significant decrease on mussel's respiration rate after exposure to different SLS concentrations, an alteration that was accompanied by a decrease of bioconcentration factor along the increasing exposure gradient, especially at the highest exposure concentration. Nonetheless, the amount of SLS accumulated in organisms originated alterations in mussel's metabolic performance, with higher metabolic capacity up to 2.0 mg/L followed by a decrease at the highest tested concentration (4.0 mg/L). Mussels exposed to SLS revealed limited antioxidant defense mecanhisms but cellular damage was only observed at the highest exposure concentration (4.0 mg/L). In fact, up to 2.0 mg/L of SLS limited toxic impacts were observed, namely in terms of oxidative stress and redox balance. However, since mussel's respiration rate was greatly affected by the presence of SLS, the present study may highlight the potential threat of SLS towards marine bivalves, limiting their filtration capacity and, thus, affecting their global physiological development (including growth and reproduction) and ultimely their biochemical performance (afecting their defense capacity towards stressful conditons).

Effects of BDE-47 exposure on immune-related parameters of Mytilus galloprovincialis

The persistent pollutants polybrominated diphenyl ethers (PBDEs) have been demonstrated to produce several negative effects on marine organisms. Although Mytilus galloprovincialis was extensively studied as model system, the effects of PBDEs on the innate immune system of mussels remains unclear. In this study, except for the control treatment, specimens of M. galloprovincialis were fed with microalgae treated with increasing concentrations of PBDEs (maximum level 100 ng L^-1 of BDE-47 per day). BDE-47 treatment was maintained for 15 days and then the animals were fed with the same control diet, without contaminants, for 15 days. Samples of haemolymph (HL) were obtained at T0, T15 and T30 days of the experiment to evaluate different parameters related to immunity, such as neutral red retention time, and peroxidase, protease, antiprotease, lysozyme and bactericidal activities. BDE-47 exposure for 15 days affected both the stability of haemocytes and humoral parameters. In addition, the obtained results indicated that, at 30 days, after 15 days of culture without contaminant, the immune parameters were still affected, as some of them did not return to the basal levels, and others remained stimulated. Overall the results indicate that BDE-47 exposures at environmentally realistic levels may affect various aspects of immune function in M. galloprovincialis, acting as stressor that can compromise the general welfare.