The Organophosphate Chlorpyrifos Interferes with the Responses to 17β-Estradiol in the Digestive Gland of the Marine Mussel Mytilus galloprovincialis

BACKGROUND: Many pesticides have been shown to act as endocrine disrupters. Although the potencies of currently used pesticides as hormone agonists/antagonists are low compared with those of natural ligands, their ability to act via multiple mechanisms might enhance the biological effect. The organophosphate Chlorpyrifos (CHP) has been shown to be weakly estrogenic and cause adverse neurodevelopmental effects in mammals. However, no information is available on the endocrine effects of CHP in aquatic organisms. In the digestive gland of the bivalve Mytilus galloprovincialis, a target tissue of both estrogens and pesticides, the possible effects of CHP on the responses to the natural estrogen 17β-estradiol (E(2)) were investigated. METHODOLOGY/PRINCIPAL FINDINGS: Mussels were exposed to CHP (4.5 mg/l, 72 hrs) and subsequently injected with E(2) (6.75 ng/g dw). Responses were evaluated in CHP, E(2) and CHP/E(2) treatment groups at 24 h p.i. by a biomarker/transcriptomic approach. CHP and E(2) induced additive, synergistic, and antagonistic effects on lysosomal biomarkers (lysosomal membrane stability, lysosome/cytoplasm volume ratio, lipofuscin and neutral lipid accumulation). Additive and synergistic effects were also observed on the expression of estrogen-responsive genes (GSTπ, catalase, 5-HTR) evaluated by RT-Q-PCR. The use of a 1.7K cDNA Mytilus microarray showed that CHP, E(2) and CHP/E(2), induced 81, 44, and 65 Differentially Expressed Genes (DEGs), respectively. 24 genes were exclusively shared between CHP and CHP/E(2), only 2 genes between E(2) and CHP/E(2). Moreover, 36 genes were uniquely modulated by CHP/E(2). Gene ontology annotation was used to elucidate the putative mechanisms involved in the responses elicited by different treatments. CONCLUSIONS: The results show complex interactions between CHP and E(2) in the digestive gland, indicating that the combination of certain pesticides and hormones may give rise to unexpected effects at the molecular/cellular level. Overall, these data demonstrate that CHP can interfere with the mussel responses to natural estrogens

Environmental and vegetation controls on the spatial variability of CH4 emission from wet-sedge and tussock tundra ecosystems in the Arctic

Aims Despite multiple studies investigating the environmental controls on CH4 fluxes from arctic tundra ecosystems, the high spatial variability of CH4 emissions is not fully understood. This makes the upscaling of CH4 fluxes from plot to regional scale, particularly challenging. The goal of this study is to refine our knowledge of the spatial variability and controls on CH4 emission from tundra ecosystems. Methods CH4 fluxes were measured in four sites across a variety of wet-sedge and tussock tundra ecosystems in Alaska using chambers and a Los Gatos CO2 and CH4 gas analyser. Results All sites were found to be sources of CH4, with northern sites (in Barrow) showing similar CH4 emission rates to the southernmost site (ca. 300 km south, Ivotuk). Gross primary productivity (GPP), water level and soil temperature were the most important environmental controls on CH4 emission. Greater vascular plant cover was linked with higher CH4 emission, but this increased emission with increased vascular plant cover was much higher (86 %) in the drier sites, than the wettest sites (30 %), suggesting that transport and/or substrate availability were crucial limiting factors for CH4 emission in these tundra ecosystems. Conclusions Overall, this study provides an increased understanding of the fine scale spatial controls on CH4 flux, in particular the key role that plant cover and GPP play in enhancing CH4 emissions from tundra soils

Interactive visualization applied to multivariate geochemical data: A case study

Geochemical survey data have commonly been analysed combining methods from several disciplinesstatistics, geostatistics, geographic information technology, visualization. In initial stages of analysis, tables are often used to describe the data and present statistical measures. Far too often the original data are manipulated in one or another way, for example, using mathematical transformations, or interpolation of points to a surface. It is the author's opinion that raw geochemical data should be used in initial stages of data description, thus preserving the original details. This is not a simple task, as geochemical data are commonly complex, multivariate, and collected on irregular grid. Data contain outliers, element contents vary within thousands of ppm (parts per million), and different chemical elements may be correlated. In the present study a graphical approach has been used to study distribution of 5 heavy metals in glacial till. Using interactive visualization and multiple linked views of the data, the following issues were addressed: multi-element outliers, spatial trends, multi-element correlations and patterns. Interactive graphical techniques proved to be especially suitable for studying outliers and identifying and locating samples that are redundant and may be removed from data without loss of information. Visualization using linked views gave valable insights about metal correlations and spatial trends. As the development of appropriate tools for analysing multivariate spatial data are still in its early stages, visualization freeware seems to be a good alternative providing powerful, easy to use and intuitive techniques for exploratory data analysis

Endotoxin and cytokines increase hepatic messenger RNA levels and serum concentrations of apolipoprotein J (clusterin) in Syrian hamsters.

Infection and inflammation induce alterations in hepatic synthesis and plasma concentrations of the acute phase proteins. Our results show that apolipoprotein (apo) J is a positive acute phase protein. Endotoxin (LPS), tumor necrosis factor (TNF), and interleukin (IL)-1 increased hepatic mRNA and serum protein levels of apo J in Syrian hamsters. Hepatic apo J mRNA levels increased 10- to 15-fold with doses of LPS from 0.1 to 100 micrograms/100 g body weight within 4 h and were elevated for > or = 24 h. Serum apo J concentrations were significantly increased by 16 h and further elevated to 3.3 times that of control, 24 h after LPS administration. Serum apo J was associated with high density lipoprotein and increased fivefold in this fraction, after LPS administration. Hepatic apo J mRNA levels increased 3.5- and 4.6-fold, with TNF and IL-1, respectively, and 8.2-fold with a combination of TNF and IL-1. Serum apo J concentrations were increased 2.3-fold by TNF, 79% by IL-1, and 2.9-fold with a combination of TNF and IL-1. These results demonstrate that apo J is a positive acute phase protein