Perchlorate in The Great Lakes: Isotopic Composition and Origin

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ^(18)O, Δ^(17)O) and chlorine (δ^(37)Cl) along with the abundance of the radioactive isotope ^(36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. Δ^(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ^(18)O values range from −4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ^(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The ^(36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10^(–12) (Lake Ontario) to 6.7 × 10^(–11) (Lake Superior). These ^(36)ClO_4– abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high ^(36)ClO_4– abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of ^(36)Cl-enriched perchlorate deposited during the period of elevated atmospheric ^(36)Cl activity following thermonuclear bomb tests in the Pacific Ocean

Curcumin-induced HDAC inhibition and attenuation of medulloblastoma growth in vitro and in vivo

<p>Abstract</p> <p>Background</p> <p>Medulloblastoma is the most common brain tumor in children, and its prognosis is worse than for many other common pediatric cancers. Survivors undergoing treatment suffer from serious therapy-related side effects. Thus, it is imperative to identify safer, effective treatments for medulloblastoma. In this study we evaluated the anti-cancer potential of curcumin in medulloblastoma by testing its ability to induce apoptosis and inhibit tumor growth <it>in vitro </it>and <it>in vivo </it>using established medulloblastoma models.</p> <p>Methods</p> <p>Using cultured medulloblastoma cells, tumor xenografts, and the Smo/Smo transgenic medulloblastoma mouse model, the antitumor effects of curcumin were tested <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>Curcumin induced apoptosis and cell cycle arrest at the G2/M phase in medulloblastoma cells. These effects were accompanied by reduced histone deacetylase (HDAC) 4 expression and activity and increased tubulin acetylation, ultimately leading to mitotic catastrophe. In <it>in vivo </it>medulloblastoma xenografts, curcumin reduced tumor growth and significantly increased survival in the Smo/Smo transgenic medulloblastoma mouse model.</p> <p>Conclusions</p> <p>The <it>in vitro </it>and <it>in vivo </it>data suggest that curcumin has the potential to be developed as a therapeutic agent for medulloblastoma.</p

Perchlorate in The Great Lakes: Isotopic Composition and Origin

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ¹⁸O, Δ¹⁷O) and chlorine (δ³⁷Cl) along with the abundance of the radioactive isotope ³⁶Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ³⁷Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ¹⁸O values range from −4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ¹⁷O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The ³⁶Cl/Cl ratio of perchlorate varies widely from 7.4 × 10^–12 (Lake Ontario) to 6.7 × 10^–11 (Lake Superior). These ³⁶ClO₄^– abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high ³⁶ClO₄^– abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of ³⁶Cl-enriched perchlorate deposited during the period of elevated atmospheric ³⁶Cl activity following thermonuclear bomb tests in the Pacific Ocean

Developing marine protected area networks in the Coral Triangle: good practices for expanding the Coral Triangle Marine Protected Area System

The Coral Triangle Marine Protected Area System aspires to become a region-wide, comprehensive, ecologically representative and well-managed system of marine protected areas (MPAs) and MPA networks. The development of this system will proceed primarily through the implementation of ecological, social, and governance MPA networks at the sub-national scale. We describe six case studies that exemplify different approaches taken to develop MPA networks in the Coral Triangle region at different scales: Nusa Penida in Indonesia; Tun Mustapha Park in Malaysia; Kimbe Bay in Papua New Guinea; Verde Island Passage in the Philippines; The Lauru Ridges to Reefs Protected Area Network in Choiseul, Solomon Islands; and Nino Konis Santana Park in Timor Leste. Through synthesis of these case studies, we identify five common themes that contributed to successful outcomes: (1) the need for multi-stakeholder and cross-level management institutions; (2) the value of integrating cutting-edge science with local knowledge and community-based management; (3) the importance of building local capacity; (4) using multiple-use zoning to balance competing objectives; and (5) participation in learning and governance networks. These lessons will be invaluable in guiding future efforts to expand the Coral Triangle Marine Protected Area System, and provide important insights for MPA practitioners elsewhere