Search

Abstract Myeloid differentiation factor 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6) are two critical signal transducers in toll-like receptor (TLR) pathway. In the present study, we identified and characterized the homologues of MyD88 and TRAF6 in Qihe crucian carp Carassius auratus , termed as CaMyD88 and CaTRAF6 , respectively, and examined their roles during pathogenic infection. Full-length cDNA of CaMyD88 was 2463 bp, including a 191 bp 5′-untranslated region (UTR), a 1417 bp 3′-UTR, and an 855 bp open reading frame (ORF) encoding for a putative protein with 284 amino acids. Full-length cDNA of CaTRAF6 was identified to be 2555 bp, consisting of a 52 bp 5′-UTR, an 871 bp 3′-UTR, and a 1632 bp ORF encoding a protein of 543 amino acids. Deduced amino acid sequences of CaMyD88 and CaTRAF6 contained the typical domains (CaMyD88: death domain and TIR domain; CaTRAF6: one RING-type zinc finger domain, two TRAF-type zinc finger domains, one coiled-coil region, and one conserved C-terminal meprin and TRAF homology domain) as in other fish. Quantitative Real-Time PCR (qRT-PCR) analysis revealed that both CaMyD88 and CaTRAF6 were ubiquitously expressed throughout the development stages and appeared to be developmentally regulated. In addition, CaMyD88 and CaTRAF6 had a broadly distribution of expression in all examined eleven tissues of healthy fish, although the transcript levels varied among the different tissues. Moreover, it was found that mRNA expressions of CaMyD88 and CaTRAF6 were generally up-regulated after stimulation by polyI:C, flagellin, and Aeromonas hydrophila in spite of the down-regulation appeared at some time points or tissues. These results indicated that CaMyD88 and CaTRAF6 play the critical roles in the immune defense of Qihe crucian carp against pathogenic invasion. The present findings will provide the valuable information for understanding the innate immune responses of Qihe crucian carp and contribute to develop the preventive way against pathogens. Highlights • Full length DNA and cDNA of MyD88 and TRAF6 were respectively characterized in Carassius auratus. • Maternal CaMyD88 or CaTRAF6 mRNA was gradually consumed in early period of developmental embryos. • Target gene mRNA expressions show obvious tissue specificity. • Expression patterns of two genes show the significant responses to immune challenges. [ABSTRACT FROM AUTHOR]

In environmental epidemiology, measurements of toxicants in biological samples are often used as individual exposure assignments. It is common to obtain only one or a few exposure biomarkers per person and use those measurements to represent each person's relevant toxicant exposure for a given health outcome, even though most exposure biomarkers can fluctuate over time. When the timing of the exposure reflected by the biomarker measurement is misaligned with disease development especially if it occurs after the disease outcome, results could be subject to reverse causality or exposure measurement error. This study aimed to use an approximate Bayesian computation (ABC) method to improve PFOA exposure estimates and characterize the effects of PFOA on preeclampsia in the C8 Studies. Serum PFOA concentrations were measured in blood samples collected during 2005–2006 in West Virginia and Ohio (the C8 Studies), and residential and water use histories and pregnancy outcomes were obtained from self-reports. Our previous results may have been influenced by the choice of methods for characterizing PFOA exposures. Here we use an ABC method to combine measured PFOA serum concentrations and environmentally modeled PFOA concentrations to reconstruct historical PFOA exposures. We also expanded our previous work by assuming more realistic lognormal distributions for key input parameters in the exposure and pharmacokinetic models. Compared to using fixed values of model parameters and Monte Carlo simulations, ABC produced similar Spearman correlations between estimated and measured serum PFOA concentrations, yet substantially reduced the mean squared error by over 50%. Based on ABC, compared to previous studies, we found a similar adjusted odds ratio (AOR) for the association between PFOA and preeclampsia. Bayesian combination of modeled exposure and measured biomarker concentrations can reduce exposure measurement error compared to modeled exposure. • ABC can reduce exposure measurement error by combining biomarker measurements with modeled serum concentrations. • PFOA was positively associated with preeclampsia, yet the association was not statistically significant in this study. • Effect estimates of PFOA and preeclampsia were driven by the rank order of exposure estimates, rather than exact exposure. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the serum of the general US population. Food, drinking water, consumer products, dust, and air have been assessed as PFAS exposure sources for humans. The effects of various types of carpeting on serum PFAS concentrations have been less studied, despite the known use of PFAS in stain-resistant carpet treatments. This study aimed to examine the associations between serum PFAS concentrations and type of residential flooring among the general US population aged 12 years and older using the 2005–2006 National Health and Nutrition Examination Survey (NHANES). We used multiple linear regressions adjusted for complex survey design and relevant covariates to analyze the relations between serum PFAS concentrations and type of floor covering (smooth surface, low pile carpet, medium to high pile carpet, and combination of carpet and smooth surface), as well as other potential exposure factors. We used multiple imputation to address missing values. We found significantly higher serum concentrations of perfluorohexane sulfonic acid (PFHxS) and 2-(N -methyl-perfluorooctane sulfonamido) acetic acid (MeFOSAA) in US residents residing in homes with low pile carpeting compared with those residing in homes with smooth surface. We concluded that among US residents aged 12 years and older residing in homes with low pile carpeting in the home in 2005–2006, on average 24% and 19% of the PFHxS and MeFOSAA body burdens, respectively, could be attributed to carpeting. We found associations between other types of floor covering (medium to high pile carpet, combination of carpet and smooth surface) and some PFAS concentrations compared with the smooth surface, but these results were less consistent and generally not statistically significant. Additionally, a group Wald Chi-squared test showed a significant result for PFOS, indicating different contributions of various types of flooring to PFOS serum concentration. Our results are representative of the general US population at the time of the survey, and potentially informative regarding ongoing PFAS exposure from a variety of sources including carpeting. • Various types of carpeting may present different PFAS exposure for humans. • Low pile carpet is associated with increased serum PFHxS and MeFOSAA concentrations. • Stain-resistance carpet treatment could explain accountable human PFAS exposure. [ABSTRACT FROM AUTHOR]