DNA damage in B and T lymphocytes of farmers during one pesticide spraying season

Purpose The effect of one pesticide spraying seasonon DNA damage was measured on B and T lymphocytesamong open-field farmers and controls.Methods At least two peripheral blood samples were collectedfrom each individual: one in a period without anypesticide application, several weeks after the last use (January,at period P0), and another in the intensive pesticidespraying period (May or June, at period P4). DNA damagewas studied by alkaline comet assay on isolated B or Tlymphocytes.Results Longitudinal comparison of DNA damageobserved at both P0 and P4 periods revealed a statisticallysignificant genotoxic effect of the pesticide spraying seasonin both B (P = 0.02) and T lymphocytes (P = 0.02) in exposed farmers. In contrast, non-farmers did not showany significant modifications. DNA damage levels in Band T lymphocytes were significantly higher in farmersthan in non-farmers during the P4 period (P = 0.003 andP = 0.001 for B and T lymphocytes, respectively) but notduring the P0 period. The seasonal effect observed amongfarmers was not correlated with either total farm area, farmarea devoted to crops or recent solar exposure. On average,farmers used pesticides for 21 days between P0 and P4.Between the two time points studied, there was a tendencyfor a potential effect of the number of days of fungicidetreatments (r2 = 0.43; P = 0.11) on T lymphocyte DNAdamage.Conclusions A genotoxic effect was found in lymphocytesof farmers exposed to pesticides, suggesting in particularthe possible implication of fungicides

The Drosophila ATM ortholog, dATM, mediates the response to ionizing radiation and to spontaneous DNA damage during development.

Cells of metazoan organisms respond to DNA damage by arresting their cell cycle to repair DNA, or they undergo apoptosis. Two protein kinases, ataxia-telangiectasia mutated (ATM) and ATM and Rad-3 related (ATR), are sensors for DNA damage. In humans, ATM is mutated in patients with ataxia-telangiectasia (A-T), resulting in hypersensitivity to ionizing radiation (IR) and increased cancer susceptibility. Cells from A-T patients exhibit chromosome aberrations and excessive spontaneous apoptosis. We used Drosophila as a model system to study ATM function. Previous studies suggest that mei-41 corresponds to ATM in Drosophila; however, it appears that mei-41 is probably the ATR ortholog. Unlike mei-41 mutants, flies deficient for the true ATM ortholog, dATM, die as pupae or eclose with eye and wing abnormalities. Developing larval discs exhibit substantially increased spontaneous chromosomal telomere fusions and p53-dependent apoptosis. These developmental phenotypes are unique to dATM, and both dATM and mei-41 have temporally distinct roles in G2 arrest after IR. Thus, ATM and ATR orthologs are required for different functions in Drosophila; the developmental defects resulting from absence of dATM suggest an important role in mediating a protective checkpoint against DNA damage arising during normal cell proliferation and differentiation

A Dietary Mobile App for Patients Undergoing Hemodialysis:Prospective Pilot Study to Improve Dietary Intakes

© 2020 Cosette Fakih El Khoury, Rik Crutzen, Jos M G A Schols, Ruud J G Halfens, Mirey Karavetian. Background: Mobile technology has an impact on the health care sector, also within dietetics. Mobile health (mHealth) apps may be used for dietary assessment and self-monitoring, allowing for real-time reporting of food intakes. Changing eating behaviors is quite challenging, and patients undergoing hemodialysis, particularly, struggle to meet the target intakes set by dietary guidelines. Usage of mobile apps that are developed in a person-centered approach and in line with recommendations may support both patients and health care practitioners. Objective: This study is a pilot that aims at estimating the potential efficacy of a dietary intervention using a theory-based, person-centered smartphone app. Results will be used to improve both the app and a planned large-scale trial intended to assess app efficacy thoroughly. Methods: A prospective pilot study was performed at the hemodialysis unit of Al Qassimi Hospital (The Emirate of Sharjah). All patients that fulfilled the study inclusion criteria were considered eligible to be enrolled in the pilot study. Upon successful installation of the app, users met with a dietitian once a week. Outcomes were measured at baseline (T0) and 2 weeks post app usage (T1). This pilot is reported as per guidelines for nonrandomized pilot and feasibility studies and in line with the CONSORT 2010 checklist for reporting pilot or feasibility trials. Results: A total of 23 patients completed the pilot intervention. Mean energy intakes increased from 24.4 kcal/kg/day (SD 8.0) to 29.1 kcal/kg/day (SD 7.8) with a medium effect size (d=0.6, 95% CI 0.0-1.2). Mean protein intakes increased from 0.9 g/kg/day (SD 0.3) to 1.3 g/kg/day (SD 0.5) with a large effect size (d=1.0, 95% CI 0.4-1.6); mean intake of high biological value (%HBV) proteins also increased from 58.6% (SD 10.1) to 70.1% (SD 10.7) with a large effect size (d=1.1, 95% CI 0.5-1.7). Dietary intakes of minerals did not change, apart from sodium which decreased from a mean intake of 2218.8 mg/day (SD 631.6) to 1895.3 mg/day (SD 581.0) with a medium effect size (d=0.5, 95% CI 0.1-1.1). Mean serum phosphorus, potassium, and albumin levels did not change relevantly. Mean serum iron increased from 7.9 mg/dL (SD 2.8) to 11.5 mg/dL (SD 7.9) postintervention with a medium effect size (d=0.6, 95% CI 0.0-1.2). Conclusions: This pilot study showed that the KELA.AE app has the potential to improve dietary intakes. Processes related to procedure, resources, tools, and app improvement for a future trial were assessed. A more extended intervention using a randomized controlled trial is required to estimate parameters concerning app efficacy accurately

Genotoxicity and mutagenicity assessment of food contaminant mixtures present in the French diet

International audienceThrough diet, people are exposed simultaneously to a variety of contaminants (e.g. heavy metals, mycotoxins, pesticides) that could have combined adverse effects on human health. A previous study identified six main mixtures of food contaminants to which French adult consumers are exposed. These complex mixtures are comprised of 11 to 19 chemicals that have numerous toxic properties. In the present study, we investigated the genotoxic effects of these food contaminants, as single molecules and in mixtures that reflect their occurrence in the French diet, using the gammaH2AX assay in two human cell lines (HepG2, LS-174 T). Results of detailed analysis of the 49 individual contaminants (including 21 tested in this study) demonstrated a positive genotoxic response to 14 contaminants in HepG2 and 12 in LS-174 T cells. Next, our results indicated that two mixtures out of six triggered significant gammaH2AX induction after 24 hr of treatment, at concentrations for which individual compounds did not induce any DNA damage, suggesting more than additive interactions between chemicals. gammaH2AX positive mixtures were then tested for mutagenicity with the innovative in vitro PIG-A assay in HepG2 cells coupled with the soft agar colony formation assay. The two gammaH2AX positive mixtures led to a significant increase in the frequency of PIG-A GPI-deficient cells and in the number of colonies formed in soft agar. In conclusion, our study demonstrates that two mixtures of contaminants present in the French diet induce genotoxicity and mutagenicity, and that the combined effects of single molecules present in these mixtures are likely not additive, highlighting potential problems for hazard assessment of mixtures

RalB GTPase-Mediated Activation of the IκB Family Kinase TBK1 Couples Innate Immune Signaling to Tumor Cell Survival

SummaryThe monomeric RalGTPases, RalA and RalB are recognized as components of a regulatory framework supporting tumorigenic transformation. Specifically, RalB is required to suppress apoptotic checkpoint activation, the mechanistic basis of which is unknown. Reported effector proteins of RalB include the Sec5 component of the exocyst, an octameric protein complex implicated in tethering of vesicles to membranes. Surprisingly, we find that the RalB/Sec5 effector complex directly recruits and activates the atypical IκB kinase family member TBK1. In cancer cells, constitutive engagement of this pathway, via chronic RalB activation, restricts initiation of apoptotic programs typically engaged in the context of oncogenic stress. Although dispensable for survival in a nontumorigenic context, this pathway helps mount an innate immune response to virus exposure. These observations define the mechanistic contribution of RalGTPases to cancer cell survival and reveal the RalB/Sec5 effector complex as a component of TBK1-dependent innate immune signaling

Mutagenicity and genotoxicity assessment of the emerging mycotoxin Versicolorin A, an Aflatoxin B1 precursor

Aflatoxin B1 (AFB1) is the most potent natural carcinogen among mycotoxins. Versicolorin A (VerA) is a pre- cursor of AFB1 biosynthesis and is structurally related to the latter. Although VerA has already been identified as a genotoxin, data on the toxicity of VerA are still scarce, especially at low concentrations. The SOS/umu and miniaturised version of the Ames test in Salmonella Typhimurium strains used in the present study shows that VerA induces point mutations. This effect, like AFB1, depends primarily on metabolic activation of VerA. VerA also induced chromosomal damage in metabolically competent intestinal cells (IPEC-1) detected by the micro- nucleus assay. Furthermore, results from the standard and enzyme-modified comet assay confirmed the VerA- mediated DNA damage, and we observed that DNA repair pathways were activated upon exposure to VerA, as indicated by the phosphorylation and/or relocation of relevant DNA-repair biomarkers (γH2AX and 53BP1/ FANCD2, respectively). In conclusion, VerA induces DNA damage without affecting cell viability at concentra- tions as low as 0.03 μM, highlighting the danger associated with VerA exposure and calling for more research on the carcinogenicity of this emerging food contaminant

MoTea4-Mediated Polarized Growth Is Essential for Proper Asexual Development and Pathogenesis in Magnaporthe oryzae▿†

Polarized growth is essential for cellular development and function and requires coordinated organization of the cytoskeletal elements. Tea4, an important polarity determinant, regulates localized F-actin assembly and bipolar growth in fission yeast and directional mycelial growth in Aspergillus. Here, we characterize Tea4 in the rice blast fungus Magnaporthe oryzae (MoTea4). Similar to its orthologs, MoTea4-green fluorescent protein (MoTea4-GFP) showed punctate distribution confined to growth zones, particularly in the mycelial tips, aerial hyphae, conidiophores, conidia, and infection structures (appressoria) in Magnaporthe. MoTea4 was dispensable for vegetative growth in Magnaporthe. However, loss of MoTea4 led to a zigzag morphology in the aerial hyphae and a huge reduction in conidiation. The majority of the tea4Δ conidia were two celled, as opposed to the tricellular conidia in the wild type. Structure-function analysis indicated that the SH3 and coiled-coil domains of MoTea4 are necessary for proper conidiation in Magnaporthe. The tea4Δ conidia failed to produce proper appressoria and consequently failed to infect the host plants. The tea4Δ conidia and germ tubes showed disorganized F-actin structures with significantly reduced numbers of cortical actin patches. Compared to the wild-type conidia, the tea4Δ conidia showed aberrant germination, poor cytoplasmic streaming, and persistent accumulation of lipid droplets, likely due to the impaired F-actin cytoskeleton. Latrunculin A treatment of germinating wild-type conidia showed that an intact F-actin cytoskeleton is indeed essential for appressorial development in Magnaporthe. We show that MoTea4 plays an important role in organizing the F-actin cytoskeleton and is essentially required for polarized growth and morphogenesis during asexual and pathogenic development in Magnaporthe