Jiang et al., 2018
Jiang, X., Zhang, N., Yin, L., Zhang, W. L., Han, F., Liu, W. B., Chen, H. Q., Cao, J., & Liu, J. Y., “A commercial Roundup(R) formulation induced male germ cell apoptosis by promoting the expression of XAF1 in adult mice.,” Toxicology Letters, 2018, 296, 163-172, DOI: 10.1016/j.toxlet.2018.06.1067.
ABSTRACT:
Roundup(R) 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(R) of male germ cells remain unclear. We aimed to investigate the apoptosis-inducing effects of Roundup(R) 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(R) 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(R) exposure both in vitro and in vivo. Furthermore, the low expression of XIAP (X-linked inhibitor of apoptosis) induced by Roundup(R) 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(R) exposure. Taken together, our data indicated that XAF1 plays an important role in Roundup(R)-induced male germ cell apoptosis. The present study suggested that Roundup(R) exposure has potential negative implications on male reproductive health in mammals.
Hong et al., 2018
Hong, Y., Yang, X., Huang, Y., Yan, G., & Cheng, Y., “Assessment of the oxidative and genotoxic effects of the glyphosate-based herbicide Roundup on the freshwater shrimp, Macrobrachium nipponensis,” Chemosphere, 2018, 210, 896-906. DOI: 10.1016/j.chemosphere.2018.07.069.
ABSTRACT:
In the present study, an acute toxic test was performed to assess the oxidative stress and genotoxic effects of the herbicide on the freshwater shrimp Macrobrachium nipponensis. The results showed that the 48-h and 96-h LC50 values of Roundup to M. nipponensis were 57.684mg/L and 11.237mg/L, respectively. For further investigation, the shrimps were exposed to sublethal concentrations of 0.35, 0.70, 1.40, 2.80 and 5.60mg/L for 96h. A significant decrease in total haemocytes count (THC) was observed at concentration of 5.60mg/L throughout the experiment. The level of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in all the treatments decreased in a dose- and time-dependent manner except for the concentration group of 0.35mg/L. The malondialdehyde (MDA), hydrogen peroxide (H2O2) and protein carbonyl in serum increased significantly at concentrations of 2.80mg/L and 5.60mg/L. A significant decrease in acetylcholinesterase (AChE) activity was observed at each concentration (P0.05). In addition, the micronucleus (MN) frequency of haemocytes significantly increased (P0.05) at concentrations of 1.40, 2.80 and 5.60mg/L, whereas the comet ratio and %DNA in the tails exhibited a clear time- and dose-dependent response during the exposure. The analysis of the integrated biomarker response (IBR) showed the induction of oxidative stress biomarkers and the inhibition of antioxidants, and this dose-dependent relation suggests the sensitivity and availability of all the biomarkers. These results revealed that Roundup had a prominent toxic effect on M. nipponensis based on the antioxidative response inhibition and genotoxicity.
Henner and Backhaus, 2019
Hollert, Henner, & Backhaus, Thomas, “Some food for thought: a short comment on Charles Benbrook´s paper ‘How did the US EPA and IARC reach diametrically opposed conclusions on the genotoxicity of glyphosate-based herbicides?’ and its implications,” Environmental Sciences Europe, 2019, 31(1). DOI: 10.1186/s12302-019-0187-z.
ABSTRACT:
Not available. FULL TEXT
Hmielowski, 2019
Hmielowski, Tracy, “Glyphosate and Phosphate Interactions in soils,” CSA News, 2019, 64(1), DOI: 10.2134/csa2019.64.0103.
SUMMARY:
• Phosphate and glyphosate interact “competitively” when both are present in the soil.
• The application of inorganic P fertilizers after glyphosate has been applied was shown to mobilize glyphosate.
• Management strategies should consider the potential for glyphosate mobilization to reduce impacts on crops and glyphosate runoff to nearby water sources.
With both phosphorus and glyphosate being applied to agricultural fields across the globe, the chemicals are commonly present together. Phosphorus is applied as inorganic forms of P (PO₄³¯) and taken up through the plant roots. Glyphosate is absorbed through foliage, and while it readily adsorbs to soil, it has been found to degrade rapidly. The two chemicals have a competitive interaction, given the similarity between the PO₄³¯and the phosphonomethyl function group of glyphosate. This means that inorganic P fertilizers can potentially displace glyphosate, and vice versa, on the surface of soil particles. FULL TEXT
Hicks et al., 2018
Hicks, Helen L., Comont, David, Coutts, Shaun R., Crook, Laura, Hull, Richard, Norris, Ken, Neve, Paul, Childs, Dylan Z., & Freckleton, Robert P., “The factors driving evolved herbicide resistance at a national scale,” Nature Ecology & Evolution, 2018, 2(3), 529-536. DOI: 10.1038/s41559-018-0470-1.
ABSTRACT:
Repeated use of xenobiotic chemicals has selected for the rapid evolution of resistance, threatening health and food security at a global scale. Strategies for preventing the evolution of resistance include cycling and mixtures of chemicals and diversification of management. We currently lack large-scale studies that evaluate the efficacy of these different strategies for minimizing the evolution of resistance. Here we use a national-scale data set of occurrence of the weed Alopecurus myosuroides (black-grass) in the United Kingdom to address this. Weed densities are correlated with assays of evolved resistance, supporting the hypothesis that resistance is driving weed abundance at a national scale. Resistance was correlated with the frequency of historical herbicide applications, suggesting that evolution of resistance is primarily driven by intensity of exposure to herbicides, but was unrelated directly to other cultural techniques. We find that populations resistant to one herbicide are likely to show resistance to multiple herbicide classes. Finally, we show that the economic costs of evolved resistance are considerable: loss of control through resistance can double the economic costs of weeds. This research highlights the importance of managing threats to food production and healthcare systems using an evolutionarily informed approach in a proactive not reactive manner.
Hertz-Picciotto et al., 2018
Hertz-Picciotto, Irva, Sass, Jennifer B., Engel, Stephanie, Bennett, Deborah H., Bradman, Asa, Eskenazi, Brenda, Lanphear, Bruce, & Whyatt, Robin, “Organophosphate exposures during pregnancy and child neurodevelopment: Recommendations for essential policy reforms,” PLOS Medicine, 2018, 15(10). DOI: 10.1371/journal.pmed.1002671.
SUMMARY POINTS:
• Widespread use of organophosphate (OP) pesticides to control insects has resulted in ubiquitous human exposures.
• High exposures to OP pesticides are responsible for poisonings and deaths, particularly in developing countries.
• Compelling evidence indicates that prenatal exposure at low levels is putting children at risk for cognitive and behavioral deficits and for neurodevelopmental disorders.
To protect children worldwide, we recommend the following:
• Governments phase out chlorpyrifos and other OP pesticides, monitor watersheds and other sources of human exposures, promote use of integrated pest management (IPM) through incentives and training in agroecology, and implement mandatory surveillance of pesticide-related illness.
• Health professions implement curricula on the hazards from OP pesticides in nursing and medical schools and in continuing medical education courses and educate their patients and the public about these hazards.
• Agricultural entities accelerate the development of nontoxic approaches to pest control through IPM and ensure the safety of workers through training and provision of protective equipment when toxic chemicals are to be used. FULL TEXT
Harre et al., 2017
Harre, Nick T., Nie, Haozhen, Robertson, Renae R., Johnson, William G., Weller, Stephen C., & Young, Bryan G., “Distribution of Herbicide-Resistant Giant Ragweed (Ambrosia trifida) in Indiana and Characterization of Distinct Glyphosate-Resistant Biotypes,” Weed Science, 2017, 65(06), 699-709. DOI: 10.1017/wsc.2017.56.
ABSTRACT:
Giant ragweed is a highly competitive weed that continually threatens crop production systems due to evolved resistance to acetolactate synthase–inhibiting herbicides (ALS-R) and glyphosate (GR). Two biotypes of GR giant ragweed exist and are differentiated by their response to glyphosate, termed here as rapid response (RR) and non–rapid response (NRR). A comparison of data from surveys of Indiana crop fields done in 2006 and 2014 showed that GR giant ragweed has spread from 15% to 39% of Indiana counties and the NRR biotype is the most prevalent. A TaqMan ® single-nucleotide polymorphism genotyping assay was developed to identify ALS-R populations and revealed 47% of GR populations to be ALS-R as well. The magnitude of glyphosate resistance for NRR populations was 4.6 and 5.9 based on GR 50 and LD 50 estimates, respectively. For RR populations, these values were 7.8 to 9.2 for GR 50 estimates and 19.3 to 22.3 for LD 50 estimates. A novel use of the Imaging-PAM fluorometer was developed to discriminate RR plants by assessing photosystem II quantum yield across the entire leaf surface. H 2 O 2 generation in leaves of glyphosate-treated plants was also measured by 3,3′-diaminobenzidine staining and quantified using imagery analysis software. Results show photo-oxidative stress of mature leaves is far greater and occurs more rapidly following glyphosate treatment in RR plants compared with NRR and glyphosate-susceptible plants and is positively associated with glyphosate dose. These results suggest that under continued glyphosate selection pressure, the RR biotype may surpass the NRR biotype as the predominant form of GR giant ragweed in Indiana due to a higher level of glyphosate resistance. Moreover, the differential photo-oxidative stress patterns in response to glyphosate provide evidence of different mechanisms of resistance present in RR and NRR biotypes.
Guerrero Schimpf et al., 2018
Guerrero Schimpf, M., Milesi, M. M., Luque, E. H., & Varayoud, J.m “Glyphosate-based herbicide enhances the uterine sensitivity to estradiol in rats,” Journal of Endocrinology, 2018, 239(2), 197-213. DOI: 10.1530/JOE-18-0207.
ABSTRACT:
In a previous work, we detected that postnatal exposure to a glyphosate-based herbicide (GBH) alters uterine development in prepubertal rats causing endometrial hyperplasia and increasing cell proliferation. Our goal was to determine whether exposure to low-dose of a GBH during postnatal development might enhance the sensitivity of the uterus to an estrogenic treatment. Female Wistar pups were subcutaneously injected with saline solution (control) or GBH using the reference dose (2 mg/kg/day, EPA) on postnatal days (PND) 1, 3, 5, and 7. At weaning (PND21), female rats were bilaterally ovariectomized and treated with silastic capsules containing 17beta-estradiol (E2, 1mg/ml) until they were two months of age. On PND60, uterine samples were removed and processed for histology, immunohistochemistry and mRNA extraction to evaluate: i) uterine morphology, ii) uterine cell proliferation by the detection of Ki67, iii) the expression of the estrogen receptors alpha (ESR1) and beta (ESR2), and iv) the expression of WNT7A and beta-catenin. GBH-exposed animals showed increased luminal epithelial height and stromal nuclei density. The luminal and glandular epithelium were markedly hyperplastic in 43% of GBH-exposed animals. GBH exposure caused an increase in E2-induced cell proliferation in association with an induction of both ESR1 and ESR2. GBH treatment decreased membranous and cytoplasmic expression of beta-catenin in luminal and glandular epithelial cells and increased WNT7A expression in the luminal epithelium. These results suggest that early postnatal exposure to a GBH enhances the sensitivity of the rat uterus to estradiol, and induces histomorphological and molecular changes associated with uterine hyperplasia. FULL TEXT
Green, 2018
Green, J. M., “The rise and future of glyphosate and glyphosate-resistant crops,” Pest Management Science, 2018, 74(5), 1035-1039. DOI: 10.1002/ps.4462.
ABSTRACT:
Glyphosate and glyphosate-resistant crops had a revolutionary impact on weed management practices, but the epidemic of glyphosate-resistant (GR) weeds is rapidly decreasing the value of these technologies. In areas that fully adopted glyphosate and GR crops, GR weeds evolved and glyphosate and glyphosate traits now must be combined with other technologies. The chemical company solution is to combine glyphosate with other chemicals, and the seed company solution is to combine glyphosate resistance with other traits. Unfortunately, companies have not discovered a new commercial herbicide mode-of-action for over 30 years and have already developed or are developing traits for all existing herbicide types with high utility. Glyphosate mixtures and glyphosate trait combinations will be the mainstays of weed management for many growers, but are not going to be enough to keep up with the capacity of weeds to evolve resistance. Glufosinate, auxin, HPPD-inhibiting and other herbicide traits, even when combined with glyphosate resistance, are incremental and temporary solutions. Herbicide and seed businesses are not going to be able to support what critics call the chemical and transgenic treadmills for much longer. The long time without the discovery of a new herbicide mode-of-action and the epidemic of resistant weeds is forcing many growers to spend much more to manage weeds and creating a worst of times, best of times predicament for the crop protection and seed industry. (c) 2016 Society of Chemical Industry. FULL TEXT
Gillezeau et al., 2019
Gillezeau, Christina, van Gerwen, Maaike, Shaffer, Rachel M, Rana, Iemaan, Zhang, Luoping, Sheppard, Lianne, & Taioli, Emanuela, “The evidence of human exposure to glyphosate: a review,” Environmental Health, 2019, 18(1), 2. DOI: 10.1186/s12940-018-0435-5.
ABSTRACT:
BACKGROUND: Despite the growing and widespread use of glyphosate, a broad-spectrum herbicide and desiccant, very few studies have evaluated the extent and amount of human exposure.
OBJECTIVE: We review documented levels of human exposure among workers in occupational settings and the general population.
METHODS: We conducted a review of scientific publications on glyphosate levels in humans; 19 studies were identified, of which five investigated occupational exposure to glyphosate, 11 documented the exposure in general populations, and three reported on both.
RESULTS: Eight studies reported urinary levels in 423 occupationally and para-occupationally exposed subjects; 14 studies reported glyphosate levels in various biofluids on 3298 subjects from the general population. Average urinary levels in occupationally exposed subjects varied from 0.26 to 73.5 mug/L; environmental exposure urinary levels ranged from 0.16 to 7.6 mug/L. Only two studies measured temporal trends in exposure, both of which show increasing proportions of individuals with detectable levels of glyphosate in their urine over time.
CONCLUSIONS: The current review highlights the paucity of data on glyphosate levels among individuals exposed occupationally, para-occupationally, or environmentally to the herbicide. As such, it is challenging to fully understand the extent of exposure overall and in vulnerable populations such as children. We recommend further work to evaluate exposure across populations and geographic regions, apportion the exposure sources (e.g., occupational, household use, food residues), and understand temporal trends. FULL TEXT