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Alexander et al., 2006

Alexander, B. H., Burns, C. J., Bartels, M. J., Acquavella, J. F., Mandel, J. S., Gustin, C., & Baker, B. A.; “Chlorpyrifos exposure in farm families: results from the farm family exposure study;” Journal of Exposure Science and Environmental Epidemiology, 2006, 16(5), 447-456; DOI: 10.1038/sj.jes.7500475.

ABSTRACT:

We used urinary biological monitoring to characterize chlorpyrifos (O,O-diethyl-O-(3,5,6-trichloro-2-pyridinyl) phosphororthioate) exposure to farm family members from Minnesota and South Carolina who participated in the Farm Family Exposure Study. Five consecutive 24-h urine samples were obtained from 34 families of licensed pesticide applicators 1 day before through 3 days after a chlorpyrifos application. Daily 3,5,6-trichloro-2-pyridinol (TCP) urinary concentrations characterized exposure profiles of the applicator, the spouse, and children aged 4-17 years. Self-reported and observed determinants of exposure were compared to the maximum postapplication TCP concentration. All participants had detectable (> or = 1 microg/l) urinary TCP concentrations at baseline. Applicators’ peak TCP levels occurred the day after the application (geometric mean (GM) = 19.0 microg/l). Postapplication TCP change from baseline in the spouses and children was negligible, and the only reliable predictor of exposure was assisting with the application for children aged 12 years and older. The applicators’ exposure was primarily influenced by the chemical formulation (GM = 11.3 microg/l for granular and 30.9 microg/l for liquid), and the number of loads applied. Repairing equipment, observed skin contact, and eating during the application were moderately associated TCP levels for those who applied liquid formulations. Estimated absorbed doses (microg chlorpyrifos/kg bodyweight) were calculated based on TCP excretion summed over the 4 postapplication days and corrected for pharmacokinetic recovery. The GM doses were 2.1, 0.7, and 1.0 microg/kg bodyweight for applicators, spouses, and children, respectively. Chlorpyrifos exposure to farm family members from the observed application was largely determined by the extent of contact with the mixing, loading, and application process. FULL TEXT

Arnold et al., 2015

Arnold, S. M., Morriss, A., Velovitch, J., Juberg, D., Burns, C. J., Bartels, M., Aggarwal, M., Poet, T., Hays, S., & Price, P.; “Derivation of human Biomonitoring Guidance Values for chlorpyrifos using a physiologically based pharmacokinetic and pharmacodynamic model of cholinesterase inhibition;” Regulatory Toxicology and Pharmacology, 2015, 71(2), 235-243; DOI: 10.1016/j.yrtph.2014.12.013.

ABSTRACT:

A number of biomonitoring surveys have been performed for chlorpyrifos (CPF) and its metabolite (3,5,6-trichloro-2-pyridinol, TCPy); however, there is no available guidance on how to interpret these data in a health risk assessment context. To address this gap, Biomonitoring Guidance Values (BGVs) are developed using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model. The PBPK/PD model is used to predict the impact of age and human variability on the relationship between an early marker of cholinesterase (ChE) inhibition in the peripheral and central nervous systems [10% red blood cell (RBC) ChE inhibition] and levels of systemic biomarkers. Since the PBPK/PD model characterizes variation of sensitivity to CPF in humans, interspecies and intraspecies uncertainty factors are not needed. Derived BGVs represent the concentration of blood CPF and urinary TCPy associated with 95% of the population having less than or equal to 10% RBC ChE inhibition. Blood BGV values for CPF in adults and infants are 6100 ng/L and 4200 ng/L, respectively. Urinary TCPy BGVs for adults and infants are 2100 mug/L and 520 mug/L, respectively. The reported biomonitoring data are more than 150-fold lower than the BGVs suggesting that current US population exposures to CPF are well below levels associated with any adverse health effect. FULL TEXT

Cai et al., 2020

Cai, Wenyan, Zhang, Feng, Zhong, Lixin, Chen, Dongya, Guo, Haoran, Zhang, Hengdong, Zhu, Baoli, & Liu, Xin; “Correlation between CYP1A1 polymorphisms and susceptibility to glyphosate-induced reduction of serum cholinesterase: A case-control study of a Chinese population;” Pesticide Biochemistry and Physiology, 2020, 162, 23-28; DOI: 10.1016/j.pestbp.2019.07.006.

ABSTRACT:

Glyphosate (GLP) is one of the most common herbicides worldwide. The serum cholinesterase (ChE) may be affected when exposed to glyphosate. Reduction of serum ChE by herbicides is probably related to cytochrome P450 (CYP450) family polymorphisms. We suspect that the abnormal ChE caused by GLP could be correlated with the CYP family members. To determine whether CYP1B1 (rs1056827 and rs1056836) and CYP1A1 (rs1048943) gene polymorphisms and individual susceptibility to GLP-induced ChE abnormalities were interrelated in the Chinese Han population, we performed this genetic association study on a total of 230 workers previously exposed to GLP, including 115 cases with reduced serum ChE and 115 controls with normal serum ChE. Two even groups of cases and controls were enrolled. The CYP1A1 and CYP1B1 polymorphisms in both groups were genotyped using TaqMan. Subjects with the CYP1A1 rs619586 genotypes showed an increased risk of GLP-induced reduction of serum ChE, which was more evident in the following subgroups: female,>35 years old, history of GLP exposure time<10 years and>10 years, nonsmoker and nondrinker. The results show that CYP1A1 rs619586 was significantly associated with the GLP-induced reduction in serum ChE and could be a biomarker of susceptibility for Chinese GLP exposed workers. Because of a large number of people exposed to glyphosate, this study has a significance in protecting their health. FULL TEXT

Leite et al., 2019

Leite, S. B., Franco de Diana, D. M., Segovia Abreu, J. A., Avalos, D. S., Denis, M. A., Ovelar, C. C., Samaniego Royg, M. J., Thielmann Arbo, B. A., & Corvalan, R.; “DNA damage induced by exposure to pesticides in children of rural areas in Paraguay;” Indian Journal of Medical Research, 2019, 150(3), 290-296; DOI: 10.4103/ijmr.IJMR_1497_17.

ABSTRACT:

BACKGROUND & OBJECTIVES:

Chronic exposure to pesticides can damage DNA and lead to cancer, diabetes, respiratory diseases and neurodegenerative and neurodevelopment disorders. The objective of this study was to determine the frequency of DNA damage through the comet assay and micronucleus (MN) test in two groups of children, under 10 yr of age living in rural Paraguay and in relation to pesticide exposure.

METHODS:

Two groups of 5 to 10 yr old children were formed; the exposed group (group A, n=43), born and currently living in a community dedicated to family agriculture and surrounded by transgenic soybean crops, and the control group (group B, n=41), born and living in a community dedicated to family agriculture with biological control of pests. For each child, 2000 cells were studied for the MN test and 200 cells for the comet assay.

RESULTS:

The comparison between exposed and control children revealed significant differences in biomarkers studied for the measurement of genetic damage (cell death and DNA damage). The median of MN was higher in the exposed group (6 vs. 1) (P <0.001). Binucleated cells (2.9 vs. 0.5, P <0.001); broken eggs (5.5 vs. 1.0, P <0.001); karyorrhexis (6.7 vs. 0.5, P <0.001); kariolysis (14.0 vs. 1.0, P <0.001); pyknosis (7.4 vs. 1.2, P <0.001) and condensed chromatin (25.5 vs. 7.0, P <0.001) were significantly higher in the exposed group. The values of tail length (59.1 vs 37.2 mum); tail moment (TM) (32.8 vs. 14.4 mum); TM olive (15.5 vs. 6); % DNA tail (45.2 vs. 27.6) and % DNA head (54.8 vs. 72.4), were significantly different between the two groups.

INTERPRETATIONS & CONCLUSIONS:

In children exposed to pesticides, a greater genotoxic and cytotoxic effect was observed compared to non-exposed children. Our findings suggest that monitoring of genetic toxicity in population exposed to pesticides and agrochemicals should be done.

FULL TEXT

Sherwin et al., 2019

Sherwin, E., Bordenstein, S. R., Quinn, J. L., Dinan, T. G., & Cryan, J. F.; “Microbiota and the social brain;” Science, 2019, 366(6465); DOI: 10.1126/science.aar2016.

ABSTRACT:

Sociability can facilitate mutually beneficial outcomes such as division of labor, cooperative care, and increased immunity, but sociability can also promote negative outcomes, including aggression and coercion. Accumulating evidence suggests that symbiotic microorganisms, specifically the microbiota that reside within the gastrointestinal system, may influence neurodevelopment and programming of social behaviors across diverse animal species. This relationship between host and microbes hints that host-microbiota interactions may have influenced the evolution of social behaviors. Indeed, the gastrointestinal microbiota is used by certain species as a means to facilitate communication among conspecifics. Further understanding of how microbiota influence the brain in nature may be helpful for elucidating the causal mechanisms underlying sociability and for generating new therapeutic strategies for social disorders in humans, such as autism spectrum disorders (ASDs). FULL TEXT

Lajmanovich et al., 2019

Lajmanovich, R. C., Peltzer, P. M., Attademo, A. M., Martinuzzi, C. S., Simoniello, M. F., Colussi, C. L., Cuzziol Boccioni, A. P., & Sigrist, M.; “First evaluation of novel potential synergistic effects of glyphosate and arsenic mixture on Rhinella arenarum (Anura: Bufonidae) tadpoles;” Heliyon, 2019, 5(10), e02601; DOI: 10.1016/j.heliyon.2019.e02601.

ABSTRACT:

The toxicity of glyphosate-based herbicide (GBH) and arsenite (As(III)) as individual toxicants and in mixture (50:50 v/v, GBH-As(III)) was determined in Rhinella arenarum tadpoles during acute (48 h) and chronic assays (22 days). In both types of assays, the levels of enzymatic activity [Acetylcholinesterase (AChE), Carboxylesterase (CbE), and Glutathione S-transferase (GST)] and the levels of thyroid hormones (triiodothyronine; T3 and thyroxine; T4) were examined. Additionally, the mitotic index (MI) of red blood cells (RBCs) and DNA damage index were calculated for the chronic assay. The results showed that the LC50 values at 48 h were 45.95 mg/L for GBH, 37.32 mg/L for As(III), and 30.31 mg/L for GBH-As(III) (with similar NOEC = 10 mg/L and LOEC = 20 mg/L between the three treatments). In the acute assay, Marking’s additive index (S = 2.72) indicated synergistic toxicity for GBH-As(III). In larvae treated with GBH and As(III) at the NOEC-48h (10 mg/L), AChE activity increased by 36.25% and 33.05% respectively, CbE activity increased by 22.25% and 39.05 % respectively, and GST activity increased by 46.75% with the individual treatment with GBH and by 131.65 % with the GBH-As(III) mixture. Larvae exposed to the GBH-As(III) mixture also showed increased levels of T4 (25.67 %). In the chronic assay at NOEC-48h/8 (1.25 mg/L), As(III) and GBH-As(III) inhibited AChE activity (by 39.46 % and 35.65%, respectively), but did not alter CbE activity. In addition, As(III) highly increased (93.7 %) GST activity. GBH-As(III) increased T3 (97.34%) and T4 (540.93%) levels. Finally, GBH-As(III) increased the MI of RBCs and DNA damage. This study demonstrated strong synergistic toxicity of the GBH-As(III) mixture, negatively altering antioxidant systems and thyroid hormone levels, with consequences on RBC proliferation and DNA damage in treated R. arenarum tadpoles. FULL TEXT

Ichikawa et al., 2019

Ichikawa, G., Kuribayashi, R., Ikenaka, Y., Ichise, T., Nakayama, S. M. M., Ishizuka, M., Taira, K., Fujioka, K., Sairenchi, T., Kobashi, G., Bonmatin, J. M., & Yoshihara, S.; “LC-ESI/MS/MS analysis of neonicotinoids in urine of very low birth weight infants at birth;” Plos One, 2019, 14(7), e0219208; DOI: 10.1371/journal.pone.0219208.

ABSTRACT:

OBJECTIVES:

Neonicotinoid insecticides are widely used systemic pesticides with nicotinic acetylcholine receptor agonist activity that are a concern as environmental pollutants. Neonicotinoids in humans and the environment have been widely reported, but few studies have examined their presence in fetuses and newborns. The objective of this study is to determine exposure to neonicotinoids and metabolites in very low birth weight (VLBW) infants.

METHODS:

An analytical method for seven neonicotinoids and one neonicotinoid metabolite, N-desmethylacetamiprid (DMAP), in human urine using LC-ESI/MS/MS was developed. This method was used for analysis of 57 urine samples collected within 48 hours after birth from VLBW infants of gestational age 23-34 weeks (male/female = 36/21, small for gestational age (SGA)/appropriate gestational age (AGA) = 6/51) who were admitted to the neonatal intensive care unit of Dokkyo Hospital from January 2009 to December 2010. Sixty-five samples collected on postnatal day 14 (M/F = 37/22, SGA/AGA = 7/52) were also analyzed.

RESULTS:

DMAP, a metabolite of acetamiprid, was detected in 14 urine samples collected at birth (24.6%, median level 0.048 ppb) and in 7 samples collected on postnatal day 14 (11.9%, median level 0.09 ppb). The urinary DMAP detection rate and level were higher in SGA than in AGA infants (both p<0.05). There were no correlations between the DMAP level and infant physique indexes (length, height, and head circumference SD scores).

CONCLUSION:

These results provide the first evidence worldwide of neonicotinoid exposure in newborn babies in the early phase after birth. The findings suggest a need to examine potential neurodevelopmental toxicity of neonicotinoids and metabolites in human fetuses.

FULL TEXT

Qiu et al., 2020

Qiu, Shengnan, Fu, Huiyang, Zhou, Ruiying, Yang, Zheng, Bai, Guangdong, & Shi, Baoming; “Toxic effects of glyphosate on intestinal morphology, antioxidant capacity and barrier function in weaned piglets;” Ecotoxicology and Environmental Safety, 2020, 187; DOI: 10.1016/j.ecoenv.2019.109846.

ABSTRACT:

At present, the public is paying more attention to the adverse effects of pesticides on human and animal health and the environment. Glyphosate is a broad-spectrum pesticide that is widely used in agricultural production. In this manuscript, the effects of diets containing glyphosate on intestinal morphology, intestinal immune factors, intestinal antioxidant capacity and the mRNA expression associated with the Nrf2 signaling pathway were investigated in weaned piglets. Twenty-eight healthy female hybrid weaned piglets (Duroc × Landrace × Yorkshire) were randomly selected with an average weight of 12.24 ± 0.61 kg. Weaned piglets were randomly assigned into 4 treatment groups and fed a basal diet supplemented with 0, 10, 20, and 40 mg/kg glyphosate for a 35-day feeding trial. We found that glyphosate had no effect on intestinal morphology. In the duodenum, glyphosate increased the activities of CAT and SOD (linear, P < 0.05) and increased the levels of MDA (linear and quadratic, P < 0.05). In the duodenum, glyphosate remarkably increased the relative mRNA expression levels of Nrf2 (linear and quadratic, P < 0.05) and NQO1 (linear and quadratic, P < 0.05) and reduced the relative mRNA expression levels of GPx1, HO-1 and GCLM (linear and quadratic, P < 0.05). In the jejunum, glyphosate remarkably increased the relative mRNA expression levels of Nrf2 (linear and quadratic, P < 0.05) and decreased the relative mRNA expression levels of GCLM (linear and quadratic, P < 0.05). Glyphosate increased the mRNA expression levels of IL-6 in the duodenum (linear and quadratic, P < 0.05) and the mRNA expression levels of IL-6 in the jejunum (linear, P < 0.05). Glyphosate increased the mRNA expression of NF-κB in the jejunum (linear, P = 0.05). Additionally, the results demonstrated that glyphosate linearly decreased the ZO-1 mRNA expression levels in the jejunum and the mRNA expression of claudin-1 in the duodenum (P < 0.05). In the duodenum, glyphosate increased the protein expression levels of Nrf2 (linear, P = 0.025). Overall, glyphosate exposure may result in oxidative stress in the intestines of piglets, which can be alleviated by enhancing the activities of antioxidant enzymes and self-detoxification. FULL TEXT

Daisley et al., 2018

Daisley, B. A., Trinder, M., McDowell, T. W., Collins, S. L., Sumarah, M. W., & Reid, G.; “Microbiota-Mediated Modulation of Organophosphate Insecticide Toxicity by Species-Dependent Interactions with Lactobacilli in a Drosophila melanogaster Insect Model;” Applied and Environmental Microbiology, 2018, 84(9); DOI: 10.1128/AEM.02820-17.

ABSTRACT:

Despite the benefits to the global food supply and agricultural economies, pesticides are believed to pose a threat to the health of both humans and wildlife. Chlorpyrifos (CP), a commonly used organophosphate insecticide, has poor target specificity and causes acute neurotoxicity in a wide range of species via the suppression of acetylcholinesterase. This effect is exacerbated 10- to 100-fold by chlorpyrifos oxon (CPO), a principal metabolite of CP. Since many animal-associated symbiont microorganisms are known to hydrolyze CP into CPO, we used a Drosophila melanogaster insect model to investigate the hypothesis that indigenous and probiotic bacteria could affect CP metabolism and toxicity. Antibiotic-treated and germfree D. melanogaster insects lived significantly longer than their conventionally reared counterparts when exposed to 10 muM CP. Drosophila melanogaster gut-derived Lactobacillus plantarum, but not Acetobacterindonesiensis, was shown to metabolize CP. Liquid chromatography tandem-mass spectrometry confirmed that the L. plantarum isolate preferentially metabolized CP into CPO when grown in CP-spiked culture medium. Further experiments showed that monoassociating germfree D. melanogaster with the L. plantarum isolate could reestablish a conventional-like sensitivity to CP. Interestingly, supplementation with the human probiotic Lactobacillus rhamnosus GG (a strain that binds but does not metabolize CP) significantly increased the survival of the CP-exposed germfree D. melanogaster This suggests strain-specific differences in CP metabolism may exist among lactobacilli and emphasizes the need for further investigation. In summary, these results suggest that (i) CPO formation by the gut microbiota can have biologically relevant consequences for the host, and (ii) probiotic lactobacilli may be beneficial in reducing in vivo CP toxicity.IMPORTANCE An understudied area of research is how the microbiota (microorganisms living in/on an animal) affects the metabolism and toxic outcomes of environmental pollutants such as pesticides. This study focused specifically on how the microbial biotransformation of chlorpyrifos (CP; a common organophosphate insecticide) affected host exposure and toxicity parameters in a Drosophila melanogaster insect model. Our results demonstrate that the biotransformation of CP by the gut microbiota had biologically relevant and toxic consequences on host health and that certain probiotic lactobacilli may be beneficial in reducing CP toxicity. Since inadvertent pesticide exposure is suspected to negatively impact the health of off-target species, these findings may provide useful information for wildlife conservation and environmental sustainability planning. Furthermore, the results highlight the need to consider microbiota composition differences between beneficial and pest insects in future insecticide designs. More broadly, this study supports the use of beneficial microorganisms to modulate the microbiota-mediated biotransformation of xenobiotics. FULL TEXT

Xia et al., 2018

Xia, X., Sun, B., Gurr, G. M., Vasseur, L., Xue, M., & You, M.; “Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.);” Frontiers in Microbiology, 2018, 9, 25; DOI: 10.3389/fmicb.2018.00025.

ABSTRACT:

The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L.), a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes), Enterobacter sp. (Proteobacteria), and Serratia sp. (Proteobacteria) from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella, while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species. FULL TEXT

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