%0 Journal Article %J Mutat Res %D 2017 %T Personal samplers of bioavailable pesticides integrated with a hair follicle assay of DNA damage to assess environmental exposures and their associated risks in children. %A Vidi, Pierre-Alexandre %A Kim A Anderson %A Haiying Chen %A Rebecca Anderson %A Salvador-Moreno, Naike %A Mora, Dana C %A Carolyn M Poutasse %A Paul J Laurienti %A Daniel, Stephanie S %A Thomas A Arcury %K Biological Availability %K Child %K Community-Based Participatory Research %K DNA Damage %K DNA Repair %K Environmental Exposure %K Hair Follicle %K Humans %K North Carolina %K Pesticides %K Risk Assessment %K Specimen Handling %X

Agriculture in the United States employs youth ages ten and older in work environments with high pesticide levels. Younger children in rural areas may also be affected by indirect pesticide exposures. The long-term effects of pesticides on health and development are difficult to assess and poorly understood. Yet, epidemiologic studies suggest associations with cancer as well as cognitive deficits. We report a practical and cost-effective approach to assess environmental pesticide exposures and their biological consequences in children. Our approach combines silicone wristband personal samplers and DNA damage quantification from hair follicles, and was tested as part of a community-based participatory research (CBPR) project involving ten Latino children from farmworker households in North Carolina. Our study documents high acceptance among Latino children and their caregivers of these noninvasive sampling methods. The personal samplers detected organophosphates, organochlorines, and pyrethroids in the majority of the participants (70%, 90%, 80%, respectively). Pesticides were detected in all participant samplers, with an average of 6.2±2.4 detections/participant sampler. DNA damage in epithelial cells from the sheath and bulb of plucked hairs follicles was quantified by immunostaining 53BP1-labled DNA repair foci. This method is sensitive, as shown by dose response analyses to γ radiations where the lowest dose tested (0.1Gy) led to significant increased 53BP1 foci density. Immunolabeling of DNA repair foci has significant advantages over the comet assay in that specific regions of the follicles can be analyzed. In this cohort of child participants, significant association was found between the number of pesticide detections and DNA damage in the papilla region of the hairs. We anticipate that this monitoring approach of bioavailable pesticides and genotoxicity will enhance our knowledge of the biological effects of pesticides to guide education programs and safety policies.

%B Mutat Res %V 822 %P 27-33 %8 2017 Oct %G eng %R 10.1016/j.mrgentox.2017.07.003 %0 Journal Article %J Oecologia %D 2014 %T Elevational differences in trait response to UV-B radiation by long-toed salamander populations. %A Thurman, Lindsey L %A Garcia, Tiffany S %A Peter D Hoffman %K Altitude %K Animals %K Behavior, Animal %K Deoxyribodipyrimidine Photo-Lyase %K DNA Damage %K Ecosystem %K Female %K Oviposition %K Stress, Physiological %K Ultraviolet Rays %K Urodela %X

Amphibian species capable of optimizing trait response to environmental stressors may develop complex strategies for defending against rapid environmental change. Trait responses may differ between populations, particularly if stressor strength varies across spatial or temporal gradients. Ultraviolet-B (UV-B) radiation is one such stressor that poses a significant threat to amphibian species. We examined the ability of long-toed salamanders (Ambystoma macrodactylum) at high- and low-elevation breeding sites to cooperatively employ behavioral and physiological trait responses to mediate UV-B damage. We performed a microhabitat survey to examine differences in oviposition behavior and UV-B conditions among breeding populations at high- (n = 3; >1,500 m) and low-elevation (n = 3; <100 m) sites. We found significant differences in oviposition behavior across populations, with females at high-elevation sites selecting oviposition substrates in UV-B protected microhabitats. We also collected eggs (n = 633) from each of the breeding sites for analysis of photolyase activity, a photoreactivating enzyme that repairs UV-B damage to the DNA, using a photoproduct immunoassay. Our results revealed no significant differences in photolyase activity between long-toed salamander populations at high and low elevations. For high-elevation salamander populations, relatively low physiological repair capabilities in embryos appear to be buffered by extensive behavioral modifications to reduce UV-B exposure and standardize developmental temperatures. This study provides valuable insight into environmental stress responses via the assessment of multiple traits in allowing sensitive species to persist in rapidly changing landscapes.

%B Oecologia %V 175 %P 835-45 %8 2014 Jul %G eng %N 3 %R 10.1007/s00442-014-2957-z %0 Journal Article %J Methods Mol Biol %D 1999 %T Measurement of activities of cyclobutane-pyrimidine-dimer and (6-4)-photoproduct photolyases. %A John B Hays %A Peter D Hoffman %K Chromatography, Thin Layer %K Deoxyribodipyrimidine Photo-Lyase %K DNA %K DNA Damage %K DNA Primers %K DNA Repair %K Polymerase Chain Reaction %K Pyrimidine Dimers %K Substrate Specificity %K Ultraviolet Rays %B Methods Mol Biol %V 113 %P 133-46 %8 1999 %G eng %R 10.1385/1-59259-675-4:133 %0 Journal Article %J Proc Natl Acad Sci U S A %D 1994 %T UV repair and resistance to solar UV-B in amphibian eggs: a link to population declines? %A Andrew R Blaustein %A Peter D Hoffman %A Hokit, D G %A Kiesecker, J M %A Walls, S C %A John B Hays %K Animals %K Anura %K Bufonidae %K Deoxyribodipyrimidine Photo-Lyase %K DNA %K DNA Damage %K DNA Repair %K Female %K Models, Biological %K Ovum %K Population Dynamics %K Radiation Tolerance %K Ranidae %K Species Specificity %K Ultraviolet Rays %X

The populations of many amphibian species, in widely scattered habitats, appear to be in severe decline; other amphibians show no such declines. There is no known single cause for the declines, but their widespread distribution suggests involvement of global agents--increased UV-B radiation, for example. We addressed the hypothesis that differential sensitivity among species to UV radiation contributes to these population declines. We focused on species-specific differences in the abilities of eggs to repair UV radiation damage to DNA and differential hatching success of embryos exposed to solar radiation at natural oviposition sites. Quantitative comparisons of activities of a key UV-damage-specific repair enzyme, photolyase, among oocytes and eggs from 10 amphibian species were reproducibly characteristic for a given species but varied > 80-fold among the species. Levels of photolyase generally correlated with expected exposure of eggs to sunlight. Among the frog and toad species studied, the highest activity was shown by the Pacific treefrog (Hyla regilla), whose populations are not known to be in decline. The Western toad (Bufo boreas) and the Cascades frog (Rana cascadae), whose populations have declined markedly, showed significantly lower photolyase levels. In field experiments, the hatching success of embryos exposed to UV radiation was significantly greater in H. regilla than in R. cascadae and B. boreas. Moreover, in R. cascadae and B. boreas, hatching success was greater in regimes shielded from UV radiation compared with regimes that allowed UV radiation. These observations are thus consistent with the UV-sensitivity hypothesis.

%B Proc Natl Acad Sci U S A %V 91 %P 1791-5 %8 1994 Mar 01 %G eng %N 5