The exposure in ovo to glyphosate on the integrity of intestinal epithelial tight junctions of chicks

Glyphosate is an ingredient widely used in various commercial formulations, including Roundup®. This study focused on tight junctions and the expression of inflammatory genes in the small intestine of chicks. On the sixth day of embryonic development, the eggs were randomly assigned to three groups: the control group (CON, n = 60), the glyphosate group (GLYP, n = 60), which received 10 mg of active glyphosate/kg egg mass, and the Roundup®-based glyphosate group also received 10 mg of glyphosate. The results indicated that the chicks exposed to glyphosate or Roundup® exhibited signs of oxidative stress. Additionally, histopathological alterations in the small intestine tissues included villi fusion, complete fusion of some intestinal villi, a reduced number of goblet cells, and necrosis of some submucosal epithelial cells in chicks. Genes related to the small intestine (ZO-1, ZO-2, Claudin-1, Claudin-3, JAM2, and Occludin), as well as the levels of pro-inflammatory cytokines (IFNγ, IL-1β, and IL-6), exhibited significant changes in the groups exposed to glyphosate or Roundup® compared to the control group. In conclusion, the toxicity of pure glyphosate or Roundup® likely disrupts the small intestine of chicks by modulating the expression of genes associated with tight junctions in the small intestine.

Effect of glyphosate, its metabolite AMPA, and the glyphosate formulation Roundup® on brown trout (Salmo trutta f. fario) gut microbiome diversity

Glyphosate is used worldwide as a compound of pesticides and is detectable in many environmental compartments. It enters water bodies primarily through drift from agricultural areas so that aquatic organisms are exposed to this chemical, especially after rain events. Glyphosate is advertised and sold as a highly specific herbicide, which interacts with the EPSP synthase, an enzyme of the shikimate metabolism, resulting in inhibition of the synthesis of vital aromatic amino acids. However, not only plants but also bacteria can possess this enzyme so that influences of glyphosate on the microbiomes of exposed organisms cannot be excluded. Those influences may result in subtle and long-term effects, e.g., disturbance of the symbiotic interactions of bionts with microorganisms of their microbiomes. Mechanisms how the transformation product aminomethylphosphonic acid (AMPA) of glyphosate might interfere in this context have not understood so far. In the present study, molecular biological fingerprinting methods showed concentration-dependent effects of glyphosate and AMPA on fish microbiomes. In addition, age-dependent differences in the composition of the microbiomes regarding abundance and diversity were detected. Furthermore, the effect of exposure to glyphosate and AMPA was investigated for several fish pathogens of gut microbiomes in terms of their gene expression of virulence factors associated with pathogenicity. In vitro transcriptome analysis with the fish pathogen Yersinia ruckeri revealed that it is questionable whether the observed effect on the microbiome is caused by the intended mode of action of glyphosate, such as the inhibition of EPSP synthase activity.

Involvement of glyphosate in disruption of biotransformation P450 enzymes and hepatic lipid metabolism in chicken

The current study investigated the potentially harmful consequences of pure glyphosate or Roundup® on CYP family members and lipid metabolism in newly hatched chicks. On the sixth day, 225 fertilized eggs were randomly divided into three treatments: (1) the control group injected with deionized water, (2) the glyphosate group injected with 10 mg pure glyphosate/Kg egg mass and (3) the Roundup group injected 10 mg the active ingredient glyphosate in Roundup®/Kg egg. The results of the study revealed a reduction in hatchability in chicks treated with Roundup®. Moreover, change of Lipid concentration in serum and the liver-treated groups. Additionally, increased liver function enzymes and increased oxidative stress in the glyphosate and Roundup® groups. Furthermore, liver tissues showed histological changes and several lipid deposits in glyphosate-treated groups. Hepatic CYP1A2 and CYP1A4 expressions were significantly increased (p < .05) after glyphosate exposure, and suppression of CYP1C1 mRNA expression was significant (p < .05) after Roundup® exposure. The pro-inflammatory cytokines genes IFN-γ and IL-1β expression were significantly increased (p < .05) after Roundup® exposure. In addition, there were significant differences in the levels of expression genes which are related to lipid synthesis or catabolism in the liver. In conclusion, in ovo glyphosate exposure caused disruption of biotransformation, pro-inflammatory and lipid metabolism in chicks.

Degradation of commercial glyphosate-based herbicide via advanced oxidative processes in aqueous media and phytotoxicity evaluation using maize seeds

Glyphosate is a herbicide that acts as a broad-spectrum, non-selective, post-emergence systemic pest controller. Its continuing, increasing, and excessive use in many countries in recent years poses a significant threat to the environment and human health due to the prevalence of this herbicide in water bodies and its impact on non-target organisms. In this context, it is essential to develop processes aimed at the non-selective degradation of glyphosate and its by-products. In this study, various advanced oxidative processes were applied: Fenton, electro-Fenton, photoelectro-oxidation, and photoelectro-Fenton, with the objective of oxidizing glyphosate in the commercial product Roundup®. The resultant oxidation products and the phytotoxicological effect on maize seed germination were also analyzed. Following each treatment, chemical oxygen demand (COD), total organic carbon (TOC), glyphosate degradation, and oxidation by-product formation were analyzed. The treated solutions were used to germinate maize seeds for 7 days in a germination chamber applying a photoperiod of 12 h at 24 °C. The % of germination, protein and hydrogen peroxide (H2O2) content, lipid peroxidation extent (MDA), and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities were determined. The photoelectro-Fenton treatment was the most effective in degrading glyphosate, operating synergistically to break glyphosate bonds, thereby generating non-toxic short-chain molecules. Maize seed germination was satisfactory (> 50 %), but the persistent formation of reactive oxygen species (ROS) led to increased antioxidant activities of SOD, CAT, and POD enzymes acting in a compensatory manner against ROS, thus sustaining the photosynthetic apparatus. Hormesis, a stimulatory effect of glyphosate, was also observed in the presence of low concentrations of glyphosate.

Derivation of water quality criteria for glyphosate and its formulations to protect aquatic life in China

Extensive use of the herbicide glyphosate leads to a high detection rate in the environment and potential risks to nontarget aquatic life. China ranks first globally in the production and consumption of glyphosate, but there are no glyphosate water quality criteria (WQCs) for protecting aquatic life. Here, data on the acute and chronic toxicity of glyphosate and glyphosate-based formulations (GBFs) to freshwater aquatic life were collected and screened. Significant differences in species sensitivity distributions (SSDs) and toxicity values for acute or chronic toxicity were found between glyphosate and GBFs. The hazardous concentrations for 5% of species (HC₅) of glyphosate or GBFs between native and nonnative species were different, and native species were found to be more sensitive to the toxicity of glyphosate. The acute and chronic WQCs derived with the SSD method for glyphosate based on the toxicity data for native species in China were 3.35 and 0.26 mg/L, respectively, and those found for GBFs were 0.21 and 0.005 mg/L, respectively. The WQCs in this study were quite different from those estimated using similar statistical extrapolation methods in other countries, which reflects the differences in species sensitivity to glyphosate toxicity in different regions. The hazard quotients (HQs) were calculated based on the WQCs and concentrations of glyphosate in some surface waters in China and indicated that glyphosate exhibits medium or high hazard risk in some samples of Tai Lake, surface water in Guiyang, fishpond water in Chongqing, rural drinking water, and surface water and reservoir water in Henan Province. The WQCs of glyphosate and GBFs have scientific significance for the exposure and pollution control of herbicide formulations and the protection of aquatic life in China.

The Cardiotoxic Effect of Roundup® is not Induced by Glyphosate: A Non-specific Blockade of Human CaV1.2 Channels

In Roundup®, the active principle glyphosate is formulated with adjuvants that help it to penetrate the plants' cell membranes. Several reports and reviews report cardiovascular effects of Roundup®, pointing the presence of arrhythmias as a potential consequence of Roundup® toxicity and death cause. However, it still remains debatable whether these cardiac events are related to glyphosate per se or to the Roundup® adjuvants. The present study aims to compare the pro-arrhythmogenic properties of Roundup® and glyphosate in an animal model and in human cardiomyocytes. In isolated guinea pig heart, the cardiotoxicity of Roundup® (significant effect on heart rate and depressive effect on ventricular contractility) was demonstrated with the highest concentrations (100 µM). In human cardiomyocytes, the cardiotoxicity is confirmed by a marked effect on contractility and a strong effect on cell viability. Finally, this Roundup® depressive effect on heart contractility is due to a concentration-dependent blocking effect on cardiac calcium channel CaV1.2 with an IC50 value of 3.76 µM. Surprisingly, no significant effect on each parameter has been shown with glyphosate. Glyphosate was devoid of major effect on cardiac calcium channel with a maximal effect at 100 µM (- 27.2 ± 1.7%, p < 0.01). In conclusion, Roundup® could induce severe cardiac toxicity by a blockade of CaV1.2 channel, leading to a worsening of heart contractility and genesis of arrhythmias. This toxicity could not be attributed to glyphosate.

Proteomic profiling of royal jelly produced by Apis mellifera L. exposed to food containing herbicide-based glyphosate

Royal jelly (RJ) is rich in protective elements associated with collective immune defenses in the hive of Apis mellifera. Exposure of bees to glyphosate-based herbicides causes ultrastructural changes in the hypopharyngeal glands and a reduction in the production of RJ. However, the effects of glyphosate-based herbicides on the protein composition of RJ and consequences for the hive are unknown. Thus, we performed proteomic profiling of royal jelly produced in hives of A. mellifera exposed to food containing 1,5 μL of Roundup® (2.16 mg. g-1 of glyphosate). The production of RJ was carried out in six hives, following the method of artificial production of queens. The combs containing 80 grafting cells were introduced into the hives, and the collection of royal jelly was performed after 72 h. Two treatments were determined based on hive feeding and the hive as the experimental unit: Control and "Roundup®". Royal jelly from the Roundup® treatment hives was compared to the Control hives. Proteins with differences in expression were identified by mass spectrometry. Only the proteins present in all three biological replicates were considered in the differential abundance analysis, using Student's t-test (p-value < 0.05, two-tailed). Hives that received food containing Roundup®, analysis showed alterations in protein profile in the RJ produced therein. In total, 24 proteins were identified, and the accumulation of Major royal jelly protein 3 (MRJP3) was downregulated, showing a significant reduction in hives exposed to food containing Roundup® in relation to control hives (t = 0.0017). MRJP3 acts analogously to polyclonal antigen-antibody reactions, performing functions related to immunity in bees of different ages and castes. To the best of our knowledge, this is the first study to demonstrate changes in the proteomic profile of RJ caused by glyphosate-based herbicides, indicating its negative effects on the nutrition and social immunity of bees.

Metabolomic and Transcript Analysis Revealed a Sex-Specific Effect of Glyphosate in Zebrafish Liver

Glyphosate is a component of commonly used herbicides for controlling weeds in crops, gardens and municipal parks. There is increasing awareness that glyphosate-based herbicides, in addition to acting on plants, may also exert toxicity in wildlife and humans. In this study, male and female adult zebrafish were exposed to 700 µg/L of glyphosate (GLY), for 28 days. We used the metabolomic approach and UHPLC-ESI-MS to analyze liver samples to investigate the adverse effects of glyphosate on hepatic metabolism. The impact of GLY was found to be sex-specific. In female, GLY exposure affected purine metabolism by decreasing the levels of AMP, GMP and inosinic acid, consequently increasing uric acid levels with respect to the control (CTRL). Exposure to GLY also caused a decrease of UMP levels in the pyrimidine metabolism pathway. In male, GLY exposure decreased the aminoadipic acid within the lysine degradation pathway. Transcript analysis of genes involved in stress response, oxidative stress and the immune system were also performed. Results demonstrated an increased stress response in both sexes, as suggested by higher nr3c1 expression. However, the hsp70.2 transcript level was increased in female but decreased in male. The results demonstrated reduced sod1, sod2, and gpx1a in male following exposure to GLY, indicating an impaired oxidative stress response. At the same time, an increase in the cat transcript level in female was observed. mRNA levels of the pro-inflammatory interleukins litaf and cxcl8b.1 were increased in female. Taken together, the results provide evidence of disrupted nucleotide hepatic metabolism, increased stress inflammatory response in female and disruption of oxidative stress response in male.

Dietary Behavior of Drosophila melanogaster Fed with Genetically-Modified Corn or Roundup®

With the rise in concern about GMOs and pesticides on human health, we have utilized Drosophila melanogaster as a model organism for understanding the effects of Roundup-Ready^® GMO diets on health. We recorded dietary behavior during and after exposure to a medium containing GMO or non-GMO corn, Roundup^® in organic corn medium, and sucrose with or without one of the two Roundup^® formulations. No differences in behavior were observed when Drosophila were exposed to a medium containing Roundup-Ready^® GMO or non-GMO corn. Drosophila can detect and refrain from eating sucrose containing one Roundup^® formulation, Ready-to-Use, which contains pelargonic acid in addition to glyphosate as an active ingredient. Drosophila exhibited dose-dependent increased consumption of sucrose alone after exposure to a medium containing either Roundup^® formulation. This may indicate that flies eating a medium with Roundup^® eat less and were thus hungrier when then given sucrose solution; that a medium with Roundup^® is more difficult to digest; or that a medium with Roundup^® is less nutritious, as would be the case if nutritionally important microbes grew on control medium, but not one containing Roundup^®.

Toxicological Effects of Roundup® on Drosophila melanogaster Reproduction

Herbicide use has increased dramatically since 2001, particularly Roundup®. Effective in agricultural practice, Roundup® adversely affects non-target organisms, including reproductive and endocrine systems. We exposed fruit flies, Drosophila melanogaster, to either Roundup® Ready to Use, containing pelargonic acid and glyphosate, or Roundup® Super Concentrate, that includes glyphosate and POEA, at sublethal concentrations. Both Roundup® formulations reduced ovary volume with fewer mature oocytes, most adversely at the highest concentration tested. Flies exposed within 2 h of eclosion were affected more than at 4 h, suggesting a critical period of increased ovarian sensitivity. These results support multi-species evidence that glyphosate-based herbicides interfere with normal development of the reproductive systems of non-target organisms.

Ecotoxicological Studies on the Effect of Roundup® (Glyphosate Formulation) on Marine Benthic Microalgae

Glyphosate is a very effective herbicide and the main active ingredient in Roundup®-the most extensively used herbicide in the world. Since glyphosate is highly water soluble it reaches water bodies easily in surface water runoff. This prompted us to undertake an experiment to evaluate the effects of glyphosate in Roundup® on natural communities of marine microphytobenthos. Microphytobenthos communities were obtained from the environment, and after transporting them to the laboratory and acclimatizing them, they were tested under controlled conditions. Changes in microphytobenthos composition and structure and the deteriorating condition of the cells of community-forming organisms (assessed by analyzing changes in chloroplast shape) were used to assess the impact of Roundup® on endpoints. The tests indicated that microphytobenthic communities were relatively resistant to herbicide. The species richness of the communities probably enabled them to rebuild effectively. Sensitive species were replaced by those more tolerant of glyphosate. Only at the highest glyphosate concentration (8.5 g·dm-3) tested was a strong negative effect noted that limited community abundance and eliminated some of the organisms. The dominant diatoms in the communities were replaced by intensively developing cyanobacteria, which ultimately comprised nearly 60% of all the cells observed in the communities.

Disruption of cytochrome P450 enzymes in the liver and small intestine in chicken embryos in ovo exposed to glyphosate

Glyphosate is the active component of several commercial formulations as in Roundup®. The present study was investigated the toxic effects of pure glyphosate or Roundup® on the liver and small intestine of chick embryos. On day 6, a total of 180 fertile eggs injected with deionized water (control group), 10 mg pure glyphosate, or 10 mg of the active ingredient glyphosate in Roundup®/kg egg mass. The results showed an increase in relative weights of the liver in embryos that treated with Roundup®. Furthermore, oxidative stress was observed in the embryos treated with glyphosate or Roundup®, increased total superoxide dismutase, and content of malondialdehyde in the liver and intestine; moreover, decrease of glutathione peroxidase in the liver with increased in the intestine compared with the control. Besides, glutamic-pyruvic transaminase was increased in Roundup® group compared with other groups. Moreover, histopathological alterations in the liver and intestine tissues were observed in treated groups. Suppression of hepatic CYP1A2, CYP1A4, CYP1B1, and MDR1 mRNA expression after exposed to Roundup®. Furthermore, inhibition of CYP1A4 in the duodenum, CYP1A4, and MRP2 in the jejunum in embryos exposed to glyphosate or Roundup®. In addition, glyphosate treatment caused an increase of CYP3A5, CYP1C1, and IFNY mRNA expression in the jejunum and CYP1A2 expression in the ileum, while IFN-Y gene increase in embryos treated with Roundup®. In conclusion, in ovo exposure to glyphosate caused histopathological alterations and induced oxidative stress in the liver and small intestines. Moreover, the expression of cytochrome P450, MDR1, and MRP2 transporters was also modulated in the liver and small intestines for chick embryos.

Short-term application of mulch, roundup and organic herbicides did not affect soil microbial biomass or bacterial and fungal diversity

Application of synthetic herbicides is currently the most widely used and cost-effective methods to assist with revegetation programs. However, the effects of short-term application of herbicides such as Roundup®, acetic acid, BioWeed™ and Slasher® as compared with mulch, on soil microbial biomass and microbial diversity remain unknown. This study examined the effects of short-term herbicide application on soil microbial biomass, C:N ratio, and fungal and bacterial communities at months 2 and 8 following initiation of treatment application. No effects of treatments on soil pH, C:N and microbial biomass were found. No segregation among treatments in the community structure of bacteria and fungi was observed. However, the fungal phylum Basiodiomycota had one unidentified class, which was only found in the mulch treatment, suggesting the C quality in the mulch treatment may differ compared with the other treatments. The dry and hot conditions experienced throughout the study period may have resulted in fast degradation of the herbicides and may have minimised the impacts of the herbicides on microbial diversity and community structure. Given that the research was undertaken at a single site and over only a short time frame, the results should be extrapolated with caution. Herbicides may have greater impact with long-term use. Future research will need to assess the revegetation success of each treatment and determine if the observed change in Basidiomycota profile and C quality identified in this study becomes significant over the long-term. We hypothesise that mulching may be a preferred treatment to facilitate weed control in riparian zone revegetation.

The effects of Roundup® in embryo development and energy metabolism of the zebrafish (Danio rerio)

Roundup® is currently the most widely used and sold agricultural pesticide in the world. The objective of this work was to investigate the effects of Roundup® on energy metabolism during zebrafish (Danio rerio) embryogenesis. The embryo toxicity test was performed for 96 h post-fertilisation and the sublethal concentration of Roundup® was defined as 58.3 mg/L, which resulted in failure to inflate the swim bladder. Biochemical assays were performed with viable embryos following glyphosate exposure, and no significant effects on protein, glucose, glycogen, triglyceride levels or the enzymatic activities of alanine aminotransferase and aspartate aminotransferase were observed. However, the activity of hexokinase was significantly altered following exposure to 11.7 mg/L Roundup®. Through molecular docking we have shown for the first time that the interactions of glucokinase and hexokinases 1 and 2 with glyphosate showed significant interactions in the active sites, corroborating the biochemical results of hexokinase activity in zebrafish exposed to the chemical. From the results of molecular docking interactions carried out on the Zfishglucok, ZfishHK1 and ZfishHK2 models with the glyphosate linker, it can be concluded that there are significant interactions between glyphosate and active sites of glucokinase and hexokinase 1 and 2 proteins. The present work suggests that Roundup® can induce problems in fish embryogenesis relating to the incapacity of swim bladder to inflate. This represents the first study demonstrating the interaction of glyphosate with hexokinase and its isoforms.

Roundup®, but Not Roundup-Ready® Corn, Increases Mortality of Drosophila melanogaster

Genetically modified foods have become pervasive in diets of people living in the US. By far the most common genetically modified foods either tolerate herbicide application (HT) or produce endogenous insecticide (Bt). To determine whether these toxicological effects result from genetic modification per se, or from the increase in herbicide or insecticide residues present on the food, we exposed fruit flies, Drosophila melanogaster, to food containing HT corn that had been sprayed with the glyphosate-based herbicide Roundup®, HT corn that had not been sprayed with Roundup®, or Roundup® in a variety of known glyphosate concentrations and formulations. While neither lifespan nor reproductive behaviors were affected by HT corn, addition of Roundup® increased mortality with an LC50 of 7.1 g/L for males and 11.4 g/L for females after 2 days of exposure. Given the many genetic tools available, Drosophila are an excellent model system for future studies about genetic and biochemical mechanisms of glyphosate toxicity.

A commercial Roundup® formulation induced male germ cell apoptosis by promoting the expression of XAF1 in adult mice

Roundup® is extensively used for weed control worldwide. Residues of this compound may lead to side effects of the male reproductive system. However, the toxic effects and mechanisms of Roundup® of male germ cells remain unclear. We aimed to investigate the apoptosis-inducing effects of Roundup® on mouse male germ cells and explore the role of a novel tumor suppressor XAF1 (X-linked inhibitor of apoptosis-associated factor 1) involved in this process. We demonstrated that Roundup® can impair spermatogenesis, decrease sperm motility and concentration, and increase the sperm deformity rate in mice. In addition, excessive apoptosis of germ cells accompanied by the overexpression of XAF1 occurred after Roundup® exposure both in vitro and in vivo. Furthermore, the low expression of XIAP (X-linked inhibitor of apoptosis) induced by Roundup® was inversely correlated with XAF1. Moreover, the knockdown of XAF1 attenuated germ cell apoptosis, improved XIAP expression and inhibited the activation of its downstream target proteins, caspase-3 and PARP, after Roundup® exposure. Taken together, our data indicated that XAF1 plays an important role in Roundup®-induced male germ cell apoptosis. The present study suggested that Roundup® exposure has potential negative implications on male reproductive health in mammals.

Moderate levels of glyphosate and its formulations vary in their cytotoxicity and genotoxicity in a whole blood model and in human cell lines with different estrogen receptor status

In vitro studies were conducted to determine the short-term cytotoxic and genotoxic effects of pure glyphosate and two glyphosate formulations (Roundup^® and Wipeout^®) at concentrations relevant to human exposure using whole blood (cytotoxicity) and various cancer cell lines (cytotoxicity and genotoxicity). Pure glyphosate (pure glyph) and Roundup^® (Ro) showed similar non-monotonic toxicological profiles at low dose exposure (from 10 µg/ml), whereas Wipeout^® (Wo) demonstrated a monotonic reduction in cell viability from a threshold concentration of 50 µg/ml, when tested in whole blood. We evaluated whether using various cancer cells (the estrogen-E2-responsive HEC1A, MCF7 and the estrogen-insensitive MDA-MB-231) exposed to moderate doses (75-500 µg/ml) would indicate varied toxicity and results indicated significant effects in the HEC1A cancer cells. A non-monotonic reduction in cell viability was observed in HEC1A exposed to pure glyph (75-500 µg/ml) and proliferative effects were observed after exposure to Wo (75, 125 and 250 µg/ml). Genotoxicity assessment (test concentration 500 µg/ml) demonstrated DNA damage in the HEC1A and MDA-MB-231 cells. Adjuvants and/or glyphosate impurities were potential contributing factors of toxicity based on the differential toxicities displayed by Ro and Wo in human whole blood and the HEC1A cells. This study contributes to the existing knowledge about in vitro exposure to moderate concentrations of glyphosate or glyphosate formulations at cytotoxic and genotoxic levels. In addition, a suggestion on the relevance of the estrogen receptor status of the cell lines used is provided, leading to the need to further investigate a potential endocrine disruptive role.

Proteomic analysis of the soil filamentous fungus Aspergillus nidulans exposed to a Roundup formulation at a dose causing no macroscopic effect: a functional study

Roundup® is a glyphosate-based herbicide (GBH) used worldwide both in agriculture and private gardens. Thus, it constitutes a substantial source of environmental contaminations, especially for water and soil, and may impact a number of non-target organisms essential for ecosystem balance. The soil filamentous fungus Aspergillus nidulans has been shown to be highly affected by a commercial formulation of Roundup® (R450), containing 450 g/L of glyphosate (GLY), at doses far below recommended agricultural application rate. In the present study, we used two-dimensional gel electrophoresis combined to mass spectrometry to analyze proteomic pattern changes in A. nidulans exposed to R450 at a dose corresponding to the no-observed-adverse-effect level (NOAEL) for macroscopic parameters (31.5 mg/L GLY among adjuvants). Comparative analysis revealed a total of 82 differentially expressed proteins between control and R450-treated samples, and 85% of them (70) were unambiguously identified. Their molecular functions were mainly assigned to cell detoxification and stress response (16%), protein synthesis (14%), amino acid metabolism (13%), glycolysis/gluconeogenesis/glycerol metabolism/pentose phosphate pathway (13%) and Krebs TCA cycle/acetyl-CoA synthesis/ATP metabolism (10%). These results bring new insights into the understanding of the toxicity induced by higher doses of this herbicide in the soil model organism A. nidulans. To our knowledge, this study represents the first evidence of protein expression modulation and, thus, possible metabolic disturbance, in response to an herbicide treatment at a dose that does not cause any visible effect. These data are likely to challenge the concept of "substantial equivalence" when applied to herbicide-tolerant plants.

Sub-lethal effects of a glyphosate-based commercial formulation and adjuvants on juvenile oysters (Crassostrea gigas) exposed for 35days

Glyphosate-based herbicides include active matter and adjuvants (e.g. polyethoxylated tallow amines, POEAs). In addition to a previous investigation on the effect of glyphosate on oysters, the aim of the present study was to investigate the effects of sub-chronic exposures (35days) to three concentrations (0.1, 1 and 100μgL-1) of Roundup Express® (REX) and POEAs on oysters belonging to the same age group. Low mortality rates were calculated, and only few significant differences (i.e. shell length) between exposure conditions were observed at a given date. However, when comparing the biomarker's temporal variations, some different patterns (e.g. condition index, reproduction, parameters of oxidative stress) were observed depending on the molecules and concentrations. These results suggest that a longer exposure to an environmental concentration (0.1μgL-1) of REX and POEAs could induce harmful effects on oysters.

Control of Cortaderia selloana with a glyphosate-based herbicide led to a short-term stimulation of soil fungal communities

In the north of Spain, Cortaderia selloana plants have invaded ecosystems of high ecological value. Control of this species is carried out with the application of glyphosate-based formulations. The aim of this work was to determine, under microcosm conditions, the short-term (2 months) effects of the application of a glyphosate-based herbicide (Roundup®) on C. selloana rhizosphere microbial communities. To this purpose, before and after the application of Roundup®, several parameters that provide information on the biomass, activity and diversity of rhizosphere fungal and bacterial communities (enzyme activities, basal and substrate-induced respiration, potentially mineralizable nitrogen, nitrification potential rate, ergosterol content and community-level profiles with Biolog™ plates and ARISA) were determined. We observed a stimulation of some microbial parameters, in particular those related to fungal communities. Further research is needed to determine the long-term consequences of this short-term fungal stimulation for soil functioning.

Multiple effects of a commercial Roundup® formulation on the soil filamentous fungus Aspergillus nidulans at low doses: evidence of an unexpected impact on energetic metabolism

Soil microorganisms are highly exposed to glyphosate-based herbicides (GBH), especially to Roundup® which is widely used worldwide. However, studies on the effects of GBH formulations on specific non-rhizosphere soil microbial species are scarce. We evaluated the toxicity of a commercial formulation of Roundup® (R450), containing 450 g/L of glyphosate (GLY), on the soil filamentous fungus Aspergillus nidulans, an experimental model microorganism. The median lethal dose (LD50) on solid media was between 90 and 112 mg/L GLY (among adjuvants, which are also included in the Roundup® formulation), which corresponds to a dilution percentage about 100 times lower than that used in agriculture. The LOAEL and NOAEL (lowest- and no-observed-adverse-effect levels) associated to morphology and growth were 33.75 and 31.5 mg/L GLY among adjuvants, respectively. The formulation R450 proved to be much more active than technical GLY. At the LD50 and lower concentrations, R450 impaired growth, cellular polarity, endocytosis, and mitochondria (average number, total volume and metabolism). In contrast with the depletion of mitochondrial activities reported in animal studies, R450 caused a stimulation of mitochondrial enzyme activities, thus revealing a different mode of action of Roundup® on energetic metabolism. These mitochondrial disruptions were also evident at a low dose corresponding to the NOAEL for macroscopic parameters, indicating that these mitochondrial biomarkers are more sensitive than those for growth and morphological ones. Altogether, our data indicate that GBH toxic effects on soil filamentous fungi, and thus potential impairment of soil ecosystems, may occur at doses far below recommended agricultural application rate.

A fluorescence-based hydrolytic enzyme activity assay for quantifying toxic effects of Roundup® to Daphnia magna

Daphnia magna is a widely used model organism for aquatic toxicity testing. In the present study, the authors investigated the hydrolytic enzyme activity of D. magna after exposure to toxicant stress. In vivo enzyme activity was quantified using 15 fluorogenic enzyme probes based on 4-methylumbelliferyl or 7-amino-4-methylcoumarin. Probing D. magna enzyme activity was evaluated using short-term exposure (24-48 h) to the reference chemical K2 Cr2 O7 or the herbicide formulation Roundup®. Toxicant-induced changes in hydrolytic enzyme activity were compared with changes in mobility (International Organization for Standardization standard 6341). The results showed that hydrolytic enzyme activity was quantifiable as a combination of whole body fluorescence of D. magna and the fluorescence of the surrounding water. Exposure of D. magna to lethal and sublethal concentrations of Roundup resulted in loss of whole body enzyme activity and release of cell constituents, including enzymes and DNA. Roundup caused comparable inhibition of mobility and alkaline phosphatase activity with median effective concentration values at 20 °C of 8.7 mg active ingredient (a.i.)/L to 11.7 mg a.i./L. Inhibition of alkaline phosphatase activity by Roundup was lowest at 14 °C and greater at 20 °C and 26 °C. The results suggest that the fluorescence-based hydrolytic enzyme activity assay (FLEA assay) can be used as an index of D. magna stress. Combining enzyme activity with fluorescence measurements may be applied as a simple and quantitative supplement for toxicity testing with D. magna.

Progression of DNA damage induced by a glyphosate-based herbicide in fish (Anguilla anguilla) upon exposure and post-exposure periods--insights into the mechanisms of genotoxicity and DNA repair

Roundup® is a glyphosate-based herbicide widely used with both agricultural and non-agricultural purposes, which has been demonstrated to represent a risk to non-target aquatic organisms, namely fish. Among the described effects to fish, genotoxicity has been pointed out as one of the most hazardous. However, the genotoxic mechanisms of Roundup® as well as the involvement of the oxidative DNA damage repair system are not entirely understood. Hence, this work aimed to improve the knowledge on the progression of DNA damage upon short-term exposure (3 days) and post-exposure (1-14 days) periods in association with DNA repair processes in Anguilla anguilla exposed to Roundup® (58 and 116 μg L⁻¹). DNA damage in hepatic cells was evaluated by the comet assay improved with the DNA-lesion specific endonucleases FPG and EndoIII. In order to evaluate the oxidative DNA damage repair ability, an in vitro base excision repair (BER) assay was performed, testing hepatic subcellular extracts. Besides the confirmation of the genotoxic potential of this herbicide, oxidative damage was implicit as an important mechanism of genetic damage, which showed to be transient, since DNA integrity returned to the control levels on the first day after cessation of exposure. An increased capacity to repair oxidative DNA damage emerging in the post-exposure period revealed to be a crucial pathway for the A. anguilla recovery; nevertheless, DNA repair machinery showed to be susceptible to inhibitory actions during the exposure period, disclosing another facet of the risk associated with the tested agrochemical.

Role of sediments in modifying the toxicity of two Roundup formulations to six species of larval anurans

The role of sediment in modifying the toxicity of the original formulation of Roundup® and Roundup WeatherMAX® was examined in aqueous laboratory tests. Six species of anurans (Bufo fowleri, Hyla chrysoscelis, Rana catesbeiana, Rana clamitans, Rana sphenocephala, and Rana pipiens) were exposed at Gosner stage 25 to concentrations of the 2 herbicide formulations in 96-h, static, nonrenewal experiments in the presence and absence of sediment. All species tested had lower median lethal concentration values in water-only exposures of both formulations compared with exposures with sediment. Sediment significantly altered the potency slopes in all tests with the exceptions of H. chrysoscelis and R. clamitans when exposed to the original formulation of Roundup and H. chrysoscelis and R. sphenocephala when exposed to Roundup WeatherMAX. Thresholds were significantly different in all tests, including those in which potency slopes did not differ. Based on water-sediment exposures of the original formulation of Roundup, all 6 species tested had a margin of safety when compared with the predicted environmental concentration of the highest label application rate. Of the 6 species, 5 had a margin of safety when exposed to Roundup WeatherMAX. During incidental exposures in the field, sediments and organic matter present in aquatic systems provide significant sources of environmental ligands. If used according to label instructions, both herbicides should pose minimal risk to anuran amphibians in actual field applications. Environ Toxicol Chem 2014;33:2616-2620. © 2014 SETAC.

Effects of the surfactant polyoxyethylene amine (POEA) on genotoxic, biochemical and physiological parameters of the freshwater teleost Prochilodus lineatus

The surfactant polyoxyethylene amine (POEA) is added to several formulations of glyphosate herbicides that are widely used in agriculture and can contaminate aquatic ecosystems. In the present study, an integrated approach examining genotoxic, biochemical and physiological parameters was employed to evaluate acute effects of POEA on the Neotropical fish Prochilodus lineatus. Juvenile fish were exposed to 0.15 mg·L(-1) (POEA 1), 0.75 mg·L(-1) (POEA 2) and 1.5 mg·L(-1) (POEA 3) of POEA or only water (CTR), and after 24h exposure samples of blood and liver were taken. Compared with CTR, liver of fish exposed to POEA 2 and POEA 3 showed increased activity of 7 ethoxyresorufin-O-deethylase and increased content of glutathione, whereas the activity of glutathione-S-transferase was diminished. On the other hand, fish of the group POEA 1 showed an increase in the activity of superoxide dismutase and in the occurrence of lipid peroxidation. Fish exposed to POEA 3 presented increased hepatic activity of glutathione peroxidase and reduced plasma cortisol. The exposure to POEA at all concentrations tested caused an increase in plasma lactate and a decrease in the hepatic activity of catalase, in the number of red blood cells and in hemoglobin content. The comet assay used for analyzing DNA damage in blood cells indicated the genotoxicity of the surfactant at all concentrations tested. Taken together these results show that POEA can cause effects at various levels, such as hemolysis, DNA damage and lipid peroxidation, which are directly related to an imbalance in the redox state of the fish.

Evaluation of biochemical, hematological and oxidative parameters in mice exposed to the herbicide glyphosate-Roundup(®)

We evaluated the toxicity of hepatic, hematological, and oxidative effects of glyphosate-Roundup^® on male and female albino Swiss mice. The animals were treated orally with either 50 or 500 mg/kg body weight of the herbicide, on a daily basis for a period of 15 days. Distilled water was used as control treatment. Samples of blood and hepatic tissue were collected at the end of the treatment. Hepatotoxicity was monitored by quantitative analysis of the serum enzymes ALT, AST, and γ-GT and renal toxicity by urea and creatinine. We also investigated liver tissues histopathologically. Alterations of hematological parameters were monitored by RBC, WBC, hemoglobin, hematocrit, MCV, MCH, and MCHC. TBARS (thiobarbituric acid reactive substances) and NPSH (non-protein thiols) were analyzed in the liver to assess oxidative damage. Significant increases in the levels of hepatic enzymes (ALT, AST, and γ-GT) were observed for both herbicide treatments, but no considerable differences were found by histological analysis. The hematological parameters showed significant alterations (500 mg/kg body weight) with reductions of RBC, hematocrit, and hemoglobin, together with a significant increase of MCV, in both sexes of mice. In males, there was an important increase in lipid peroxidation at both dosage levels, together with an NPSH decrease in the hepatic tissue, whereas in females significant changes in these parameters were observed only at the higher dose rate. The results of this study indicate that glyphosate-Roundup^® can promote hematological and hepatic alterations, even at subacute exposure, which could be related to the induction of reactive oxygen species.