Non-target Organisms Research Articles

Transgenerational effects of the levonorgestrel-based birth control pill in zebrafish offspring

The consumption of hormone-derived medicines, such as levonorgestrel (LNG), is increasing worldwide, and its discharge into the environment reaches non-target organisms. In our previous study, we exposed the parental generation of zebrafish to environmentally relevant concentrations of LNG during the developmental phase. Subsequently, they had grown in a tank with clean water until adulthood. Now, we allowed this parental generation to reproduce to obtain F1 progeny unexposed to LGN, in order to analyze the transgenerational effects of parental LNG exposure on the survival and hatching of unexposed F1 embryos and the stress and behavior of F1 larvae. Here, we found decreased survival rates with higher LNG concentrations, providing a transgenerational effect. This highlights the environmental impact of exposure to LNG, causing damage at the individual and population level and affecting the next generation at the beginning of development, impacting qualities in the survival of the species.

Green synthesis of silver nanoparticles using Osbeckia leschenaultiana DC extract: Optimization of synthesis, biological activities, larvicidal activity and toxicity analysis

Presently the Osbeckia leschenaultiana DC leaf - extract was used to synthesis the silver nanoparticles and the green synthesized AgNPs were characterized by UV–vis spectrophotometer, FTIR, XRD, DLS, Zeta potential and SEM. Absorbance at 405 nm was obtained in UV–vis spectrophotometer and multiple peaks emerged in FTIR analyses that represent the presence of some interesting functional groups. XRD results proved that the synthesised AgNPs were face-centered cubic and crystalline in nature. SEM revealed the particles are Cuboid and irregular forms; the particle size ranged between 70 nm and 100 nm. And the antibacterial and antioxidant characterization of green synthesized silver nanoparticles Osbeckia leschenaultiana DC leaf − extract against. Methicillin-resistant Staphylococcus aureus, Vibrio cholerae, Bacillus subtilis and Escherichia coli, revealed the potential antibacterial efficiency against gram positive bacteria Methicillin-resistant Staphylococcus aureus (23.0 ± 1.0) and Bacillus subtilis (22.0 ± 1.0) and they showed 60–70 % high antioxidant activity compared to Osbeckia leaf extract. AgNPs showed the highest mortality against Aedes aegypti with LC50 value of 49.17 µg/mL, followed by the Osbeckia leaf extract have LC50 value of 85.95 µg/mL. The toxicity profile analyzed using non-target organism Artemia salina exhibited less toxicity. The results revealed that the Osbeckia leschenaultiana DC mediated AgNPs had multifaceted antibacterial, antioxidant and larvicidal potential.

Effects of sulfamethazine and tetracycline at molecular, cellular and tissue levels in Eisenia fetida earthworms

Soil contamination by antibiotics is a global issue of great concern that contributes to the rise of bacterial antibiotic resistance and can have toxic effects on non-target organisms. This study evaluated the variations of molecular, cellular, and histological parameters in Eisenia fetida earthworms exposed to sulfamethazine (SMZ) and tetracycline (TC), two antibiotics commonly found in agricultural soils. The earthworms were exposed for 14 days to a series of concentrations (0, 10, 100, and 1000 mg/kg) of both antibiotics. SMZ and TC did not affect the survival of E. fetida, however, other effects at different levels of biological complexity were detected. The two highest concentrations of SMZ reduced the viability of coelomocytes. At the highest TC concentration, there was a noticeable decline in cell viability, acetylcholinesterase activity (neurotoxicity), and the relative presence of mucopolysaccharides in the epidermis (mucous production). Glutathione S-transferase activity decreased in all TC treatments and at the highest SMZ concentration. However, levels of malondialdehyde and protein carbonyls did not change, suggesting an absence of oxidative stress. Tetracycline was neurotoxic to E. fetida and changed the integrity of the epidermis. Both antibiotics altered the intestinal microbiota of E. fetida, leading to a reduction in the relative abundance of bacteria from the phyla Proteobacteria and Bacteroidetes, while causing an increase in the phylum Actinobacteroidota. All observed changes indicate that both SMZ and TC can disrupt the earthworms' immune system and gut microbiome, while fostering the growth of bacteria that harbour antibiotic resistance genes. Finally, both antibiotics exerted additional metabolic and physiological effects that increased the vulnerability of E. fetida to pathogens.

Amphiphilic Cationic Carbon Dots for Efficient Delivery of Light-Dependent Herbicide.

The inefficient delivery of herbicides causes unpleasant side effects on the ecological environment. Protoporphyrinogen oxidase (PPO)-inhibiting herbicides rely on the presence of external light to exert the activities and thus their performance in the field is extremely susceptible to the light environment. Here, taking acifluorfen (ACI) as a model PPO-inhibiting herbicide to enhance efficacy by boosting the utilization rate of sunlight, amphiphilic cationic CDs (CPC-CDs) from cetylpyridinium chloride (CPC) as a precursor, is first prepared as a supplementary light source generator, and subsequently co-assembled with ACI through non-covalent bond interactions to obtain the stable fluorescent nanoparticles (ACI@CPC-CDs). ACI@CPC-CDs with fascinating physicochemical properties can penetrate the leaves of weeds through the stomata and undergo a long-distance transport in the cell intervals. Under low light intensity, CPC-CDs can be applied as the internal light source to promote the formation of more singlet oxygen to damage the leaf cell membrane, consequently improving the herbicidal activity of ACI. Moreover, the safety evaluation of ACI@CPC-CDs demonstrates no risk to non-target organisms and the environment. Therefore, this work offers a promising strategy for the efficient delivery of light-dependent PPO-inhibiting herbicides and opens new insights into the application of CDs in the development of sustainable agriculture.

Neonicotinoid Residues on Filter Paper Lack Insecticidal Activity.

Neonicotinoid insecticides are used against agricultural, forest, and urban insect pests. Evaluation of dry neonicotinoid residues on treated filter paper is a commonly used method to determine the toxicity of active ingredients towards target and non-target organisms. Dry residues of four neonicotinoids, acetamiprid, dinotefuran, imidacloprid, and thiamethoxam, on filter paper did not cause significant levels of mortality in Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae) and Nezara viridula (L.) (Hemiptera: Pentatomidae) when compared to paired untreated groups. Conversely, nearly 100% mortality was observed when test insects were exposed to dry neonicotinoid residues on leaf discs and glass plate surfaces. On the other hand, dry residues of the pyrethroid bifenthrin on filter paper, leaf disks, and glass plates killed significantly more test insects when compared to untreated groups. Additional bioassays tested the toxicity of acetamiprid and thiamethoxam by evaluating the toxicity of dry residues on (1) the upper and (2) lower surfaces of treated filter paper, (3) on a glass plate underneath treated filter paper, (4) on the upper surface of treated filter paper treated with insecticide and adjuvant, and (5) dried residues on a glass plate after dipping treated filter paper in water and letting the solvent dry on the inert test surface. The results indicated that neonicotinoid insecticides applied to filter paper were adsorbed. Toxic compounds possibly move in between and binding to paper fibers so that no toxic residues were left on treated surfaces. However, adsorbed insecticides were still biologically active when washed out of filter paper and dried on an inert glass surface. The results reported here clearly demonstrate that the toxicity of neonicotinoid insecticides should not be evaluated using filter paper as a test surface.

New insights about the toxicity of 2,4-D: Gene expression analysis reveals modulation on several subcellular responses in Chironomus riparius

Herbicides are the main class of pesticides applied in crops and are capable of polluting the surrounding freshwater system; thus, understanding their impact on non-target species, whose mechanism of action is not described, helps to elucidate the real risks of these pollutants to the environment. 2,4-dichlorophenoxyacetic acid (2,4-D) is frequently detected in water and, due to its persistence, poses a risk to wildlife. In this way, the present work aimed to describe the implication of exposure to concentrations of 2,4-D already reported in aquatic environments in several physiological mechanisms of C. riparius at molecular and biochemical levels. To achieve this, bioassays were conducted with fourth instar larvae exposed to three concentrations of 2,4-D (0.1, 1.0, and 7.5 μg L−1). Larvae were collected after 24 and 96 h of exposure, and the expression of 42 genes, related to six subcellular mechanisms, was assessed by Real-Time PCR (RT-PCR). Besides, the activity of the enzymes catalase (CAT), glutathione S-transferase (GST), and acetylcholinesterase (AChE) was determined. The main metabolic route altered after exposure to 2,4-D was the endocrine system (mainly related to 20-hydroxyecdysone and juvenile hormone), confirming its endocrine disruptor potential. Four of the eleven stress response genes studied were down-regulated, and later exposure modulated DNA-repair genes suggesting genotoxic capacity. Moreover, only one gene from each detoxification phase was modulated at short exposure to 1.0 μg L−1. The molecular responses were not dose-dependent, and some early responses were not preserved after 96 h, indicating a transient response to the herbicide. Exposure to 2,4-D did not alter the activity of CAT, GST, and AChE enzymes. The responses described in this study reveal new mechanistic pathways of toxicity for 2,4-D in non-target organisms and highlight potential ecological consequences for chironomids in aquatic systems at the edges of agricultural fields.

Susceptibility of Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) to cyantraniliprole and spinetoram

ABSTRACT Integrated pest management (IPM) uses a range of control strategies to diminish pest populations. Hence, the simultaneous utilisation of synthetic insecticides and biological control agents is desirable, although hindered by the possible impact of insecticides on non-target organisms. Plutella xylostella (L.) is a common target of several pesticides in Brassica crops. However, it can also be parasitised by Tetrastichus howardi (Olliff). This study examined the susceptibility of T. howardi to dry residue of cyantraniliprole and spinetoram on inert surfaces and treated kale (Brassica oleracea var. manteiga) leaf discs at field rates (FRs = 10 g a.i. ha−1 and 25 g a.i. ha−1, respectively), 50% of the FR, and at various time intervals (ranging from 2 h to 8 days after application). Survival of T. howardi remained unaffected by cyantraniliprole and spinetoram, regardless of the pesticide rate or spraying interval. Furthermore, the presence of cyantraniliprole and spinetoram in dry residue, when kale leaves were consumed by second-instar P. xylostella larvae at LC25 and LC50 levels, did not have any detrimental impact on the survival of the parasitoids. Similarly, the exposure of T. howardi to contaminated P. xylostella larvae did not have any impact on its ability to parasitise or on the emergence of the parasitoid. Given the minimal effect of cyantraniliprole and spinetoram on T. howardi, these control strategies appear to be suitable for incorporation into an integrated approach for the management of P. xylostella in Brassica crops.

Isolation and identification of entomopathogenic fungi strains for Colorado potato beetle (Leptinotarsa decemlineata) control.

The Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) is the most widespread insect pest that causes major economic losses, especially on potatoes. Due to heavy insecticide use, this species now resists most pesticides, posing a significant control challenge. Frequent pesticide application also harms non-target organisms, the environment, and human health. Hence, utilizing biocontrol agents like entomopathogenic fungi (EPF) offers a viable alternative for pest management. The aim of this study was to identify and characterize new EPF strains isolated from soil samples and evaluate their efficacy against adult L. decemlineata under laboratory conditions. Soil samples were collected in potato fields or uncultivated areas adjacent to the field in the Czech Republic and the EPF strains were isolated using a modified Tenebrio bait method. A total of 20 fungal strains were isolated and identified using morphological and molecular markers based on the 28S rRNA, ITS, and elongation factor 1-alpha gene sequences as Beauveria bassiana (Bals.-Criv.) Vuill., Beauveria brongniartii (Sacc.) Petch, and Cordyceps fumosorosea (Wize) Kepler, B. Shrestha & Spatafora (Hypocreales: Cordycipitaceae), Purpureocillium lilacinum (Thom.) Luangsa-ard, Houbraken, Hywel-Jones & Samson (Hypocreales: Ophiocordycipitaceae), Metarhizium brunneum (Petch), and Metarhizium robertsii Bisch., Rehner & Humber (Hypocreales: Clavicipitaceae). The bioassays revealed high variability among virulence of these strains against L. decemlineata with the shortest median time to death (LT50=5 days) in M. robertsii strain MAN3b. Results shown that some EPF strains, particularly those of genera Metarhizium, can be promising biocontrol agents against the Colorado potato beetle.

Does the atrazine increase animal mortality: Unraveling through a meta-analytic study

Atrazine is one of the most used herbicides in the world, although it is banned in several countries. Pollution of terrestrial and aquatic ecosystems represents a threat to non-target organisms, with various damages already reported in different species. However, there is controversy in studies on atrazine. The question of whether atrazine increases animal mortality is not yet clearly resolved. In this context, this study aimed to carry out a meta-analytic review, focusing on studies on environmental concentrations of the herbicide atrazine to evaluate its lethal effects on various animal species. We identified and analyzed 107 datasets through a selection process that used the Scopus, PubMed, and Web of Science (WoS) databases. A significant increase in the mortality rate of animals exposed to environmental concentrations of atrazine was observed. Nematodes, amphibians, molluscs, insects, and fish showed increased mortality after exposure to atrazine. Animals in the larval and juvenile stages showed greater susceptibility when exposed to different concentrations of atrazine. Furthermore, both commercial and pure formulations resulted in high mortality rates for exposed animals. Atrazine and other pesticides had a synergistic effect, increasing the risk of mortality in animals. There are still many gaps to be filled, and this study can serve as a basis for future regulations involving atrazine.

Photolysis of dinotefuran and nitenpyram in water and ice phase: Influence mechanism of temperature over photolysis

Neonicotinoids are widely used pesticides around the world, but the photolysis of neonicotinoids in cold agricultural region are still in blank. This paper aimed to study the influence of cold temperature over photolysis of neonicotinoids. To this end, the photolysis rates and photoproducts of dinotefuran and nitenpyram in water, ice and freeze-thawing condition were determined. Coupled with quantum chemistry calculation, the influence mechanisms of temperature and medium were investigated. The results showed the photolysis rates of neonicotinoids in water condition slightly declined with the lowered temperature due to the photolysis reactions were endothermic reactions. However, the photolysis rates increased by 89.8 %, 59.2 %, 49.4 % and 9.5 % for dinotefuran and nitenpyram in ice and thawing condition, respectively. This phenomenon was posed by the concentration-enhancing effect and change of photo-chemical properties of neonicotinoids in ice condition, which included lowered bond cleavage energy, lowered first excited singlet state energy and expanded light absorption range. The photolysis pathways of the two neonicotinoids did not change in different medium, but the concentration of carboxyl products was relatively higher than that of water condition due to the more amounts of reactive oxygen species in ice medium, which might increase the secondary pollution risk after ice-off in spring due to the higher ecotoxicity to nontarget organism of these photoproducts. The influence of cold temperature and medium change should be considered for the environmental fate and risk assessment of neonicotinoids in cold agricultural region.

Microorganism-Driven 2,4-D Biodegradation: Current Status and Emerging Opportunities.

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been widely used around the world in both agricultural and non-agricultural fields due to its high activity. However, the heavy use of 2,4-D has resulted in serious environmental contamination, posing a significant risk to non-target organisms, including human beings. This has raised substantial concerns regarding its impact. In addition to agricultural use, accidental spills of 2,4-D can pose serious threats to human health and the ecosystem, emphasizing the importance of prompt pollution remediation. A variety of technologies have been developed to remove 2,4-D residues from the environment, such as incineration, adsorption, ozonation, photodegradation, the photo-Fenton process, and microbial degradation. Compared with traditional physical and chemical remediation methods, microorganisms are the most effective way to remediate 2,4-D pollution because of their rich species, wide distribution, and diverse metabolic pathways. Numerous studies demonstrate that the degradation of 2,4-D in the environment is primarily driven by enzymatic processes carried out by soil microorganisms. To date, a number of bacterial and fungal strains associated with 2,4-D biodegradation have been isolated, such as Sphingomonas, Pseudomonas, Cupriavidus, Achromobacter, Ochrobactrum, Mortierella, and Umbelopsis. Moreover, several key enzymes and genes responsible for 2,4-D biodegradation are also being identified. However, further in-depth research based on multi-omics is needed to elaborate their role in the evolution of novel catabolic pathways and the microbial degradation of 2,4-D. Here, this review provides a comprehensive analysis of recent progress on elucidating the degradation mechanisms of the herbicide 2,4-D, including the microbial strains responsible for its degradation, the enzymes participating in its degradation, and the associated genetic components. Furthermore, it explores the complex biochemical pathways and molecular mechanisms involved in the biodegradation of 2,4-D. In addition, molecular docking techniques are employed to identify crucial amino acids within an alpha-ketoglutarate-dependent 2,4-D dioxygenase that interacts with 2,4-D, thereby offering valuable insights that can inform the development of effective strategies for the biological remediation of this herbicide.

Effects of plant protection products on ecosystem functions provided by terrestrial invertebrates.

Plant protection products (PPP) are extensively used to protect plants against harmful organisms, but they also have unintended effects on non-target organisms, especially terrestrial invertebrates. The impact of PPP on ecosystem functions provided by these non-target invertebrates remains, however, unclear. The objectives of this article were to review PPP impacts on the ecosystem functions provided by pollinators, predators and parasitoids, and soil organisms, and to identify the factors that aggravate or mitigate PPP effects. The literature highlights that PPP alter several ecosystem functions: provision and maintenance of biodiversity, pollination, biotic interactions and habitat completeness in terrestrial ecosystems, and organic matter and soil structure dynamics. However, there are still a few studies dealing with ecosystem functions, with sometimes contradictory results, and consequences on agricultural provisioning services remain unclear. The model organisms used to assess PPP ecotoxicological effects are still limited, and should be expanded to better cover the wide functional diversity of terrestrial invertebrates. Data are lacking on PPP sublethal, transgenerational, and "cocktail" effects, and on their multitrophic consequences. In empirical assessments, studies on PPP unintended effects should consider agricultural-pedoclimatic contexts because they influence the responses of non-target organisms and associated ecosystem functions to PPP. Modeling might be a promising way to account for the complex interactions among PPP mixtures, biodiversity, and ecosystem functioning.

Microbes as carbendazim degraders: opportunity and challenge.

Carbendazim (methyl benzimidazol-2-ylcarbamate, CBZ) is a systemic benzimidazole carbamate fungicide and can be used to control a wide range of fungal diseases caused by Ascomycetes, Basidiomycetes and Deuteromycetes. It is widely used in horticulture, forestry, agriculture, preservation and gardening due to its broad spectrum and leads to its accumulation in soil and water environmental systems, which may eventually pose a potential threat to non-target organisms through the ecological chain. Therefore, the removal of carbendazim residues from the environment is an urgent problem. Currently, a number of physical and chemical treatments are effective in degrading carbendazim. As a green and efficient strategy, microbial technology has the potential to degrade carbendazim into non-toxic and environmentally acceptable metabolites, which in turn can dissipate carbendazim from the contaminated environment. To date, a number of carbendazim-degrading microbes have been isolated and reported, including, but not limited to, Bacillus, Pseudomonas, Rhodococcus, Sphingomonas, and Aeromonas. Notably, the common degradation property shared by all strains was their ability to hydrolyze carbendazim to 2-aminobenzimidazole (2-AB). The complete mineralization of the degradation products is mainly dependent on the cleavage of the imidazole and benzene rings. Additionally, the currently reported genes for carbendazim degradation are MheI and CbmA, which are responsible for breaking the ester and amide bonds, respectively. This paper reviews the toxicity, microbial degradation of carbendazim, and bioremediation techniques for carbendazim-contaminated environments. This not only summarizes and enriches the theoretical basis of microbial degradation of carbendazim, but also provides practical guidance for bioremediation of carbendazim-contaminated residues in the environment.

Genotoxicity of dillapiole n-butyl ether in mice for the control of Aedes aegypti

Aedes aegypti and Aedes albopictus are vectors of arboviruses and have different levels of resistance to synthetic insecticides, such as the organophosphate temephos, according to their area of occurrence. As an alternative, there are semisynthetic substances with potential insecticidal effect; however, they need to be fully tested by an effective method for the mosquito control. The semi-synthetic dillapiole n-butyl ether exhibits toxic ovicidal and larvicidal activity in both mosquito species. However, has no proven the mutagenicity and cytotoxicity risks of this larvicide in drinking water effect for consumption by non-target organisms, such as in humans neither in other vertebrates, which access pools of water contain this sprayed substance. In this sense, both of the biomarkers of the genotoxicity, the micronucleus (MN) and comet, using this substance were tested in Balb/C mice to assess the genetic damage and risks of its application as a mitigating measure against Ae. aegypti. Male specimens (n = 60) were exposed to dillapiole n-butyl ether at concentrations of 10, 20 and 40 mg/kg via a comet assay in peripheral blood (n = 30) and a micronucleus test in bone marrow cells (n = 30). The induction of mutagenicity and cytotoxicity of dillapiole n-butyl ether in these animals occurred only at a concentration of 40 mg/kg, in multiple treatments. However, dillapiole n-butyl ether at concentrations of 20 and 10 mg/kg has potential for use against Ae. aegypti in the form of a larvicide in water for consumption by humans and other vertebrates a new vector control measure.

Imidacloprid affects human cells through mitochondrial dysfunction and oxidative stress

Given their relatively low persistence and mammalian toxicity, neonicotinoid pesticides have been extensively used worldwide and are omnipresent in the environment. Recent studies have shown that neonicotinoids may pose adverse effects on non-target organisms other than the known neurotoxicity, raising emerging concerns that these insecticides might pose human health risk through additional toxicity pathways. In the present study, the mitochondria function, oxidative stress, DNA damages, and genes transcription levels were examined in the human neuroblastoma SH-SY5Y cells after 48-h exposure to imidacloprid at concentrations from 0.05 to 200 μmol/L. Results showed that imidacloprid induced mitochondrial dysfunction with the degradation of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) levels. In addition, imidacloprid caused oxidative stress by stimulating the generation of reactive oxygen species (ROS) and hydrogen peroxide (H2O2) via the disruption of calcium ion level and mitochondrial function. Ultimately, the oxidative stress continued to produce DNA damage and apoptosis in SH-SY5Y cells at imidacloprid concentrations above 47.6 μmol/L. Among the evaluated endpoints, ATP was the most sensitive, with a median activity concentration of 0.74 μmol/L. The 5 % hazard concentration of imidacloprid was estimated to be 0.69 μmol/L, which can be used as a threshold for human health risk assessment for imidacloprid. Collectively, our results provide an important support for further research on potential toxicity of neonicotinoids related to mitochondrial toxicity in humans.

Efficacy of Fusarium caatingaense and botanical extracts in controlling Dactylopius opuntiae (Hemiptera: Dactylopiidae) in the field

In this study, we evaluated the effectiveness of Fusarium caatingaense URM 6778 and URM 6779 alone and combined with aqueous extracts of Ricinus communis 5% and Nicotiana tabacum 10% against Dactylopius opuntiae in the field. The effectiveness of the extracts alone was also evaluated. The botanical extracts were subjected to phytochemical screening to identify biologically active chemical compounds. Total mortality data were corrected using the Schneider-Orelli formula. The results were submitted for analysis of variance (ANOVA), and the means were compared using Tukey’s test at 5% probability. The phytochemical screening of R. communis and N. tabacum showed that both extracts contained alkaloids, flavonoid glycosides, saponins, and tannins. According to the confirmed mortality, URM 6779 (61.67%) and URM 6778 + aqueous extract of R. communis at 5% (43.89%) were the best treatments for the control of D. opuntiae in the field. The aqueous extracts of N. tabacum at 10% and R. communis at 5% resulted in mortality rates of 75.14% and 65.32%, respectively, and are also options for controlling this insect. Despite promising results, for the applicability of such agents to be safe, investigations into their toxicity to non-target organisms and their permanence in the environment are necessary.

Cymbopogon citratus Allelochemical Volatiles as Potential Biopesticides against the Pinewood Nematode.

Traditional pesticides are based on toxic compounds that can reduce biodiversity, degrade the environment, and contribute to less healthy living. Plant allelochemicals can provide more environmentally friendly and sustainable alternatives. Essential oils (EOs) are complex mixtures of plant secondary metabolites that show strong biological activities. In the present study, the EOs of Cymbopogon citratus were screened for activity against the pinewood nematode (PWN), the causal agent of pine wilt disease. To understand their nematicidal properties, EOs were fractioned into hydrocarbon molecules and oxygen-containing compounds, and their main compounds were acquired and tested separately against the PWN. The EO oxygen-containing molecules fraction was highly active against the PWN (EC50 = 0.279 µL/mL), with citral and geraniol showing higher activities (EC50 = 0.266 and 0.341 µL/mL, respectively) than emamectin benzoate (EC50 = 0.364 µL/mL), a traditional nematicide used against the PWN. These compounds were additionally reported to be less toxic to non-target organisms (fish, invertebrates, and algae) and safer to human health (with higher reported toxicity thresholds) and predicted to exert fewer environmental impacts than traditional nematicides. Resorting to approved natural compounds can quickly leverage the development of sustainable alternatives to traditional nematicides.

Comparative Study of the Effects of Drugs Targeting Adrenergic Receptors on the Early Life Stages of Zebrafish.

Owing to the presence of drugs targeting adrenergic receptors in aquatic ecosystems, considerable attention has been directed towards their environmental distribution and fate in recent decades. However, their potential impacts on non-target aquatic organisms, particularly fish, have received relatively limited investigation. In this study, moxisylyte (MOX) and propranolol (PRO) were selected as representatives of α- or β-adrenergic receptor antagonist, respectively, and we assessed their effects on the early life stages of zebrafish, especially on the nervous and cardiovascular systems. Although both compounds exhibited marginal effects on zebrafish survival, hatching and gross abnormality following exposure to concentrations ranging from 1 to 625 μg/L, they adversely affected the development of cardiovascular and nervous systems, but through different mechanisms of action, as evidenced by variations in gene transcriptional responses and enzyme activities. Notably, cardiovascular responses appear promising for use as potential biomarkers for exposure to drugs targeting adrenergic receptors. This study enhances our understanding of the ecotoxicological risks posed by α- and β-blockers in fish. Nonetheless, further investigation is needed to elucidate the precise mechanisms underlying the impacts of drugs targeting adrenergic receptors due to our limited knowledge of the physiological functions of the adrenergic system in fish.

Florfenicol induces malformations of embryos and causes altered lipid profile, oxidative damage, neurotoxicity, and histological effects on gonads of adult sea urchin, Paracentrotus lividus

The frequent occurrence of antibiotics in the aquatic environment has engendered negative impacts on non-target organisms. The effects of the veterinary antibiotic florfenicol (FLO) during the embryo-larval development of the sea urchin, Paracentrotus lividus was assessed using four increasing concentrations (1, 2, 5 and 10 mg/L). Furthermore, FLO toxicity to adults was investigated through the analysis of oxidative damage, histopathological alterations, lipid metabolism and acetylcholinesterase activity following an exposure period of 96 h. FLO induced embryotoxicity with estimated EC50 values of 5.75, 7.56 and 3.29 mg/L after 12 h, 24 h and 48 h, respectively. It generated oxidative stress assessed as lipid peroxidation in gonads despite the increased antioxidant activity of catalase (CAT). Neurotoxicity was also evident since the AChE activity significantly decreased. Moreover, FLO affected the lipid metabolism by increasing saturated fatty acid (SFA) and monounsaturated fatty acid proportions (MUFA), except in the group exposed to 5 mg/L. The increase in polyunsaturated fatty acid (PUFA) levels and docosahexaenoic acid (DHA, C22:6n-3) proportions were noted with all FLO concentrations. Eicosapentaenoic acid (EPA, C20:5n-3) decreased, while arachidonic acid (ARA, C20:4n-6) increased in sea urchins exposed to 5 and 10 mg/L FLO. Histopathological alterations of gonadal tissues represent an additional confirmation about the toxicity of this antibiotic that might decrease the reproductive performance of this species. Nevertheless, even if reproduction of sea urchins would be partially successful, the embryotoxicity would compromise the normal development of the embryos with consequences on the population.

Effects of injudicious use of spirotetramat on Encarsia formosa's ability to control Bemisia tabaci

The excessive and frequent use of insecticides has led to serious problems with insecticide residues, impacting nontarget organisms such as the parasitoid Encarsia formosa. This study examined the growth, development, and enzyme activity of E. formosa exposed to spirotetramat at LC10, LC30, and LC50. The regression equation for the toxicity of spirotetramat toward E. formosa was Y = 5.25X–11.07. After exposure to spirotetramat, the survival rates of E. formosa sharply decreased, which occurred earlier than those in the control batch. Although the maximum daily parasitism quantity of E. formosa increased and the average parasitism number, enumerated from the 1st to the 5th day, was 53.97 after being exposed to spirotetramat at LC10, the life span of its F1 generation adults was only 8.47 days, which was significantly shorter than that in the control batch. After being exposed to spirotetramat at LC50, the average parasitism number of E. formosa was 63.30, and the developmental time of its F1 generation, enumerated from the 1st to the 5th day after exposure to spirotetramat, was significantly longer than that of the control batch. The activities of mixed function oxidase, acetylcholinesterase, carboxylesterase, and catalase increased significantly, and the rate of increase in enzyme activity was directly proportional to the increase in the concentration of spirotetramat. These results revealed that the parasitic ability of E. formosa decreased after exposure to spirotetramat at LC10, LC30, and LC50. This leads to a change in parasitoid control of pests, revealing the potential environmental threat of insecticide residues to nontarget organisms.