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Epel, D, Luckenbach T, Stevenson CN, Macmanus-Spencer LA, Hamdoun A, Smital T.  2008.  Efflux transporters: Newly appreciated roles in protection against pollutants. Environmental Science & Technology. 42:3914-3920.   10.1021/es087187v   AbstractWebsite
Hamdoun, A, Epel D.  2007.  Embryo stability and vulnerability in an always changing world. Proceedings of the National Academy of Sciences of the United States of America. 104:1745-1750.   10.1073/pnas.0610108104   AbstractWebsite

Contrary to the view that embryos and larvae are the most fragile stages of life, development is stable under real-world conditions. Early cleavage embryos are prepared for environmental vagaries by having high levels of cellular defenses already present in the egg before fertilization. Later in development, adaptive responses to the environment either buffer stress or produce alternative developmental phenotypes. These buffers, defenses, and alternative pathways set physiological limits for development under expected conditions; teratology occurs when embryos encounter unexpected environmental changes and when stress exceeds these limits. Of concern is that rapid anthropogenic changes to the environment are beyond the range of these protective mechanisms.

Smital, T, Luckenbach T, Sauerborn R, Hamdoun AM, Vega RL, Epel D.  2004.  Emerging contaminants--pesticides, PPCPs, microbial degradation products and natural substances as inhibitors of multixenobiotic defense in aquatic organisms. Mutation research. 552:101-17.   10.1016/j.mrfmmm.2004.06.006   Abstract

The environmental presence of chemosensitizers or inhibitors of the multixenobiotic resistance (MXR) defense system in aquatic organisms could cause increase in intracellular accumulation and toxic effects of other xenobiotics normally effluxed by MXR transport proteins (P-glycoprotein (P-gps), MRPs). MXR inhibition with concomitant detrimental effects has been shown in several studies with aquatic organisms exposed to both model MXR inhibitors and environmental pollutants. The presence of MXR inhibitors has been demonstrated in environmental samples from polluted locations at concentrations that could abolish P-gp transport activity. However, it is not clear whether the inhibition observed after exposure to environmental samples is a result of saturation of MXR transport proteins by numerous substrates present in polluted waters or results from the presence of powerful MXR inhibitors. And are potent environmental MXR inhibitors natural or man-made chemicals? As a consequence of these uncertainties, no official action has been taken to monitor and control the release and presence of MXR inhibitors into aquatic environments. In this paper we present our new results addressing these critical questions. Ecotoxicological significance of MXR inhibition was supported in in vivo studies that demonstrated an increase in the production of mutagenic metabolites by mussels and an increase in the number of sea urchin embryos with apoptotic cells after exposure to model MXR inhibitors. We also demonstrated that MXR inhibitors are present among both conventional and emerging man-made pollutants: some pesticides and synthetic musk fragrances show extremely high MXR inhibitory potential at environmentally relevant concentrations. In addition, we emphasized the biological transformation of crude oil hydrocarbons into MXR inhibitors by oil-degrading bacteria, and the risk potentially caused by powerful natural MXR inhibitors produced by invasive species.

Patel, S, Ramakrishnan L, Rahman T, Hamdoun A, Marchant JS, Taylor CW, Brailoiu E.  2011.  The endo-lysosomal system as an NAADP-sensitive acidic Ca(2+) store: Role for the two-pore channels. Cell Calcium. 50:157-167.   10.1016/j.ceca.2011.03.011   AbstractWebsite

Accumulating evidence suggests that the endo-lysosomal system provides a substantial store of Ca(2+) that is tapped by the Ca(2+)-mobilizing messenger, NAADP. In this article, we review evidence that NAADP-mediated Ca(2+) release from this acidic Ca(2+) store proceeds through activation of the newly described two-pore channels (TPCs). We discuss recent advances in defining the sub-cellular targeting, topology and biophysics of TPCs. We also discuss physiological roles and the evolution of this ubiquitous ion channel family. (C) 2011 Elsevier Ltd. All rights reserved.

Bonito, LT, Hamdoun A, Sandin SA.  2016.  Evaluation of the global impacts of mitigation on persistent, bioaccumulative and toxic pollutants in marine fish. Peerj. 4   10.7717/peerj.1573   AbstractWebsite

Although persistent, bioaccumulative and toxic pollutants (PBTs) are well-studied individually their distribution and variability on a global scale are largely unknown particularly in marine fish. Using 2,662 measurements collected from peer-reviewed literature spanning 1969-2012, we examined variability of five classes of PBTs, considering effects of geography, habitat, and trophic level on observed concentrations. While we see large-scale spatial patterning in some PBTs (chlordanes, polychlorinated biphenyls), habitat type and trophic level did not contribute to significant patterning, with the exception of mercury. We further examined patterns of change in PBT concentration as a function of sampling year. All PBTs showed significant declines in concentration levels through time, ranging from 15-30% reduction per decade across PBT groups. Despite consistent evidence of reductions, variation in pollutant concentration remains high, indicating ongoing consumer risk of exposure to fish with pollutant levels exceeding EPA screening values. The temporal trends indicate that mitigation programs are leffective, but that global levels decline slowly. In order for monitoring efforts to provide more targeted assessments of risk to PBT exposure, these data highlight an urgent need for improved replication and standardization of pollutant monitoring protocols for marine finfish.