Assessing effects of germline exposure to environmental toxicants by high-throughput screening in C. elegans.

Chemicals that are highly prevalent in our environment, such as phthalates and pesticides, have been linked to problems associated with reproductive health. However, rapid assessment of their impact on reproductive health and understanding how they cause such deleterious effects, remain challenging due to their fast-growing numbers and the limitations of various current toxicity assessment model systems. Here, we performed a high-throughput screen in C. elegans to identify chemicals inducing aneuploidy as a result of impaired germline function. We screened 46 chemicals that are widely present in our environment, but for which effects in the germline remain poorly understood. These included pesticides, phthalates, and chemicals used in hydraulic fracturing and crude oil processing. Of the 46 chemicals tested, 41% exhibited levels of aneuploidy higher than those detected for bisphenol A (BPA), an endocrine disruptor shown to affect meiosis, at concentrations correlating well with mammalian reproductive endpoints. We further examined three candidates eliciting aneuploidy: dibutyl phthalate (DBP), a likely endocrine disruptor and frequently used plasticizer, and the pesticides 2-(thiocyanomethylthio) benzothiazole (TCMTB) and permethrin. Exposure to these chemicals resulted in increased embryonic lethality, elevated DNA double-strand break (DSB) formation, activation of p53/CEP-1-dependent germ cell apoptosis, chromosomal abnormalities in oocytes at diakinesis, impaired chromosome segregation during early embryogenesis, and germline-specific alterations in gene expression. This study indicates that this high-throughput screening system is highly reliable for the identification of environmental chemicals inducing aneuploidy, and provides new insights into the impact of exposure to three widely used chemicals on meiosis and germline function

Sources and fates of perchlorate in soils in Chile : A case study of perchlorate dynamics in soil-crop systems using lettuce (Lactuca sativa) fields.

Perchlorate occurs naturally in the environment in deposits of nitrate and can be formed in the atmosphere and precipitate into soil. However, little is known about the occurrence and levels of perchlorate in soils and fertilizers in Chile and its impacts on agricultural systems and food safety. In this study, concentrations of perchlorate were determined in 101 surface soils and 17 fertilizers [nitrogenous (n = 8), nitrogen-phosphorous-potassium (NPK; n = 3), phosphate (n = 2) and non-nitrogenous (n = 4)] collected across Chile from 2017 to 2018. Our results show that perchlorate was detected mainly in agricultural soils (mean: 0.32 ng g−1), grassland rotation sites (0.41 ngg−1) and urban locations (0.38 ng g−1). Interestingly, elevated concentrations of perchlorate (9.66 and 54.0 ng g−1) were found in agricultural soils. All fertilizers contained perchlorate: nitrogenous fertilizers (mean: 32.6 mg kg−1), NPK (mean: 12.6 mg kg−1), non-nitrogenous fertilizers (mean: 10.2 mg kg−1) and phosphates (mean: 11.5 mg kg−1). Only one type of nitrogenous fertilizer (KNO3: 95.3 mg kg−1) exceeded the international regulation limit (50 mg kg−1). For two agronomic practices, the content of perchlorate in lettuce increased as the fertilizer application rate increased, with fertigation promoting a more significant accumulation. However, the concentrations generally remained below regulatory values. Our results suggest that fertilizers constitute an important source of perchlorate in soils.</p

Serially assessed bisphenol A and phthalate exposure and association with kidney function in children with chronic kidney disease in the US and Canada: A longitudinal cohort study.

BackgroundExposure to environmental chemicals may be a modifiable risk factor for progression of chronic kidney disease (CKD). The purpose of this study was to examine the impact of serially assessed exposure to bisphenol A (BPA) and phthalates on measures of kidney function, tubular injury, and oxidative stress over time in a cohort of children with CKD.Methods and findingsSamples were collected between 2005 and 2015 from 618 children and adolescents enrolled in the Chronic Kidney Disease in Children study, an observational cohort study of pediatric CKD patients from the US and Canada. Most study participants were male (63.8%) and white (58.3%), and participants had a median age of 11.0 years (interquartile range 7.6 to 14.6) at the baseline visit. In urine samples collected serially over an average of 3.0 years (standard deviation [SD] 1.6), concentrations of BPA, phthalic acid (PA), and phthalate metabolites were measured as well as biomarkers of tubular injury (kidney injury molecule-1 [KIM-1] and neutrophil gelatinase-associated lipocalin [NGAL]) and oxidative stress (8-hydroxy-2'-deoxyguanosine [8-OHdG] and F2-isoprostane). Clinical renal function measures included estimated glomerular filtration rate (eGFR), proteinuria, and blood pressure. Linear mixed models were fit to estimate the associations between urinary concentrations of 6 chemical exposure measures (i.e., BPA, PA, and 4 phthalate metabolite groups) and clinical renal outcomes and urinary concentrations of KIM-1, NGAL, 8-OHdG, and F2-isoprostane controlling for sex, age, race/ethnicity, glomerular status, birth weight, premature birth, angiotensin-converting enzyme inhibitor use, angiotensin receptor blocker use, BMI z-score for age and sex, and urinary creatinine. Urinary concentrations of BPA, PA, and phthalate metabolites were positively associated with urinary KIM-1, NGAL, 8-OHdG, and F2-isoprostane levels over time. For example, a 1-SD increase in ∑di-n-octyl phthalate metabolites was associated with increases in NGAL (β = 0.13 [95% CI: 0.05, 0.21], p = 0.001), KIM-1 (β = 0.30 [95% CI: 0.21, 0.40], p ConclusionsAlthough BPA and phthalate metabolites were not associated with clinical renal endpoints such as eGFR or proteinuria, there was a consistent pattern of increased tubular injury and oxidative stress over time, which have been shown to affect renal function in the long term. This raises concerns about the potential for clinically significant changes in renal function in relation to exposure to common environmental toxicants at current levels

Curcumin and Mitocur-1, 2 and 3 induce cell death in various cancer cells by SRB Assay.

<p>MCF-7, MDA-MB-231, HeLa, DU-145, and SKNSH cells were incubated with curcumin, mitocurcuminoids-1, 2, or 3 at a dose ranging from 0.1–50 µM for a period of 24 h. At the end of the treatments, cell death was assayed by SRB assay as described in Methods section. Results are expressed as IC₅₀ (µM). Values represent data in triplicates from at least three independent experiments.</p

Superoxide generation in MCF-7 cells treated with mitocur-1 detected by EPR spectroscopy using DMPO spin trap.

<p>(<b>A</b>) Cells alone; (<b>B</b>) Cells+curcumin (10 µM); (<b>C</b>) Cells+mitocur-1Mitocur- (10 µM); (<b>D</b>) Cells+mMitocur-1 (10 µM)+MnTBAP (10 µM); (<b>E</b>) xanthine+xanthine oxidase. Microwave frequency, 9.786 GHz; microwave power, 10 mW; modulation amplitude, 1 G; scan time, 30 s; no. of scans, 10.</p

Modulation of cell cycle progression by Mitocur-1.

<p>MCF-7 cells were treated with Mitocur-1 (5 and 10 µM) for a period of 24 h. (<b>A</b>) shows the flow cytometry profiles of (PI)- stained cells of control, and Mitocur-1 (5 and 10 µM) treatment as described in Methods. (<b>B</b>) Quantitative cell cycle (DNA content) distribution (% of total) in the control and treatment groups. (<b>C</b>) MCF-7 cells were treated with Mitocur-1 (5 and 10 µM) for 24 h and subjected to Western blot analysis. Representative immunoblot images of cyclin A, cyclin B1 and cyclin D1 are shown. Values are expressed Mean ± SD; (n = 4). **, significantly different from control (P<0.01).</p