2015 Atomic Spectrometry Update – a review of advances in X-ray fluorescence spectrometry and their applications

This review describes advances in the X-ray fluorescence (XRF) group of techniques published approximately between April 2014 and March 2015 and is therefore restricted to a selection of papers featuring developments in the XRF armoury. An active topic during this review period was that of imaging techniques and, more particularly of micro XRF spectrometry. Silicon-based semiconductor X-ray detectors such as SDD and Si(PIN) continue to reflect the maturity and widespread routine use of such devices. The significant expansion in studies evaluating the field use of portable XRF instrumentation in geological applications, often still proving the quality of the data, rather than adopting the technique in routine applications. New synchrotron beamlines offer previously unavailable spatial resolution and throughput for the characterisation of advanced energy materials and devices under varying temperatures and gas atmospheres. Nanomaterials feature extensively this year such as the use of nanoparticles in cancer imaging and therapy. Synchrotron radiation has become a preferred technique for the analysis of a wide range of archeological samples, artwork, museum specimens and environmental studies. There has been a substantial rise in the number of Chinese researchers investigating objects of cultural heritage, especially porcelain, glazes and glass. Advances in TXRF and related techniques continue to feature with studies on thin films and nanomaterials. Feedback on this review is most welcome and the review coordinator can be contacted using the email address provided

Effects of Hypoxia Exposure on Hepatic Cytochrome P450 1A (CYP1A) Expression in Atlantic Croaker: Molecular Mechanisms of CYP1A Down-Regulation

Hypoxia-inducible factor-α (HIF-α) and cytochrome P450 1A (CYP1A) are biomarkers of environmental exposure to hypoxia and organic xenobiotic chemicals that act through the aryl hydrocarbon receptor, respectively. Many aquatic environments heavily contaminated with organic chemicals, such as harbors, are also hypoxic. Recently, we and other scientists reported HIF-α genes are upregulated by hypoxia exposure in aquatic organisms, but the molecular mechanisms of hypoxia regulation of CYP1A expression have not been investigated in teleost fishes. As a first step in understanding the molecular mechanisms of hypoxia modulation of CYP1A expression in fish, we characterized CYP1A cDNA from croaker liver. Hypoxia exposure (dissolved oxygen, DO: 1.7 mg/L for 2 to 4 weeks) caused significant decreases in hepatic CYP1A mRNA and protein levels compared to CYP1A levels in fish held in normoxic conditions. In vivo studies showed that the nitric oxide (NO)-donor, S-nitroso-N-acetyl-DL-penicillamine, significantly decreased CYP1A expression in croaker livers, whereas the competitive inhibitor of NO synthase (NOS), Nω-nitro-L-arginine methyl ester, restored CYP1A mRNA and protein levels in hypoxia-exposed (1.7 mg DO/L for 4 weeks) fish. In vivo hypoxia exposure also markedly increased interleukin-1β (IL-1β, a cytokine), HIF-2α mRNA and endothelial NOS (eNOS) protein levels in croaker livers. Pharmacological treatment with vitamin E, an antioxidant, lowered the IL-1β, HIF-2α mRNA and eNOS protein levels in hypoxia-exposed fish and completely reversed the down-regulation of hepatic CYP1A mRNA and protein levels in response to hypoxia exposure. These results suggest that hypoxia-induced down-regulation of CYP1A is due to alterations of NO and oxidant status, and cellular IL-1β and HIF-α levels. Moreover, the present study provides the first evidence of a role for antioxidants in hepatic eNOS and IL-1β regulation in aquatic vertebrates during hypoxic stress.This study was supported by a grant from the National Oceanic and Atmospheric Administration Coastal Ocean Program Gulf of Mexico GOMEX, grant no. NA09NOS4780179 to PT, publication no. NGOMEX 1**, and National Science Foundation, grant no. IOS-1119242 to PT. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.Marine Scienc