Understanding the Toxicity of Single Hydrocarbons, Oil, and Dispersed Oil: A Species Sensitivity Assessment for Five Atlantic Coral Species

Coral reefs are keystone coastal ecosystems that are at risk of exposure to petroleum hydrocarbons from a range of sources, including oil spill incidents and chronic runoff, and are usually one of the highest valued natural resources for protection in Net Environmental Benefit Analysis (NEBA)/Spill Impact Mitigation Assessment (SIMA) of response methods and environmental damage. Previous research evaluating hydrocarbon impacts to corals has resulted in no clear characterization of sensitivity, as work has generally focused on higher-level effects, compounded by significant variability in experimental methodology. This represents an important knowledge gap in oil spill preparedness and response as it relates to the potential impact of oil spills to the coral animal and its symbiotic zooxanthellae. This research was designed to address this gap, using a standardized toxicity testing protocol to evaluate effects of the petroleum/dispersant system the Atlantic shallow-water coral species Acropora cervicornis, Porites astreoides, Siderastera siderea, Stephanocoenia intersepta, and Solenastrea bournoni. The central objective of the Coral-Tox project was to provide lethal and sub-lethal endpoints of hydrocarbon exposure for five key Atlantic coral species in order to support effective decision-making and response should a spill occur near coral reefs. The relative sensitivity of these scleractinian coral species to hydrocarbon exposure was assessed with 48-h assays using 1-methylnaphthalene, phenanthrene, and toluene, as well as non-dispersed and chemically dispersed MC252 crude oil. Effects were evaluated based on physical coral condition, mortality, photosynthetic efficiency, growth rate, and gene expression. While the threatened species A. cervicornis is the most sensitive of those tested, the acute endpoints for the single-compound tests, and the oil and chemically dispersed oil exposures indicated that corals are comparatively more resilient to narcotic chemical exposure than other coastal marine species, possibly due to the lipid-rich nature of coral tissue and their ability to secrete mucus. Typically, mortality is used to compare the effects of contaminants, but sublethal impacts are necessary for assessing impacts of petroleum spills in the environment, particularly when evaluating the relative effects of a spill to different ecosystem components included in a NEBA/SIMA. Gene expression results were used to evaluate effects of the contaminants at levels below the onset of observable physiological changes or lethality. Identifying impact pathways of hydrocarbon exposure to corals from the genomic to organismal levels provides a framework for the prediction of oil impacts on the coral animal, significantly improving model inputs to predict the effects of spill responses in coastal tropical environments

Fmoc solid phase synthesis of polyamides containing pyrrole and imidazole amino acids

Polyamides containing N-methylimidazole (Im) and N-methylpyrrole (Py) amino acids are synthetic ligands that have an affinity and specificity for DNA comparable to those of many naturally occurring DNA binding proteins. A machine-assisted Fmoc solid phase synthesis of polyamides has been optimized to afford high stepwise coupling yields (>99%). Two monomer building blocks, Fmoc-Py acid and Fmoc-Im acid, were prepared in multigram scale. Cleavage by aminolysis followed by HPLC purification affords up to 200 mg quantities of polyamide with purities and yields greater than or equal to those reported using Boc chemistry. A broader set of reaction conditions will increase the number and complexity of minor groove binding polyamides which may be prepared and help ensure compatibility with many commercially available peptide synthesizers

Bioinformatic analysis of the neprilysin (M13) family of peptidases reveals complex evolutionary and functional relationships

<p>Abstract</p> <p>Background</p> <p>The neprilysin (M13) family of endopeptidases are zinc-metalloenzymes, the majority of which are type II integral membrane proteins. The best characterised of this family is neprilysin, which has important roles in inactivating signalling peptides involved in modulating neuronal activity, blood pressure and the immune system. Other family members include the endothelin converting enzymes (ECE-1 and ECE-2), which are responsible for the final step in the synthesis of potent vasoconstrictor endothelins. The ECEs, as well as neprilysin, are considered valuable therapeutic targets for treating cardiovascular disease. Other members of the M13 family have not been functionally characterised, but are also likely to have biological roles regulating peptide signalling. The recent sequencing of animal genomes has greatly increased the number of M13 family members in protein databases, information which can be used to reveal evolutionary relationships and to gain insight into conserved biological roles.</p> <p>Results</p> <p>The phylogenetic analysis successfully resolved vertebrate M13 peptidases into seven classes, one of which appears to be specific to mammals, and insect genes into five functional classes and a series of expansions, which may include inactive peptidases. Nematode genes primarily resolved into groups containing no other taxa, bar the two nematode genes associated with <it>Drosophila </it>DmeNEP1 and DmeNEP4. This analysis reconstructed only one relationship between chordate and invertebrate clusters, that of the ECE sub-group and the DmeNEP3 related genes. Analysis of amino acid utilisation in the active site of M13 peptidases reveals a basis for their biochemical properties. A relatively invariant S1' subsite gives the majority of M13 peptidases their strong preference for hydrophobic residues in P1' position. The greater variation in the S2' subsite may be instrumental in determining the specificity of M13 peptidases for their substrates and thus allows M13 peptidases to fulfil a broad range of physiological roles.</p> <p>Conclusion</p> <p>The M13 family of peptidases have diversified extensively in all species examined, indicating wide ranging roles in numerous physiological processes. It is predicted that differences in the S2' subsite are fundamental to determining the substrate specificities that facilitate this functional diversity.</p

Adoption, Maintenance and Diffusion of Stormwater Best Management Practices: Rain Barrels

Urbanization increases the volume of stormwater runoff from homes, businesses and other paved areas of the urbanized landscape. Unable to infiltrate into the ground, stormwater is directed to facilities that can easily become overloaded and cause a variety of water quality issues. This study aims to assess urban homeowners’ motivations to adopt and maintain rain barrels, a stormwater best management practice (BMP), and evaluate how this BMP diffuses throughout a community. This research took place in the Great Bend of the Wabash River (Lafayette-West Lafayette, Indiana) and Salt Creek (Valparaiso, Indiana) watersheds and featured a mail survey of 571 residents, site performance evaluations of 130 rain barrels, a “windshield” assessment of 242 rain barrels, and 31 in-person interviews. Our results show that 88% of homeowners in the Great Bend of the Wabash River watershed have maintained their rain barrels after two years and 65% of homeowners in Salt Creek watershed after 5 years. One of the biggest issues homeowners had with maintaining their rain barrels were issues with water pressure. We also found that 94% of rain barrel owners maintain a flower or vegetable garden and their primary motivation for adopting a rain barrel was to reduce water use for their yard or house. Outreach may need to focus more on the importance of maintaining the rain barrels as well as emphasizing the connection between rain barrels and personal gardening

PIK3CA mutation enrichment and quantitation from blood and tissue

PIK3CA is one of the two most frequently mutated genes in breast cancers, occurring in 30-40% of cases. Four frequent 'hotspot' PIK3CA mutations (E542K, E545K, H1047R and H1047L) account for 80-90% of all PIK3CA mutations in human malignancies and represent predictive biomarkers. Here we describe a PIK3CA mutation specific nuclease-based enrichment assay, which combined with a low-cost real-time qPCR detection method, enhances assay detection sensitivity from 5% for E542K and 10% for E545K to 0.6%, and from 5% for H1047R to 0.3%. Moreover, we present a novel flexible prediction method to calculate initial mutant allele frequency in tissue biopsy and blood samples with low mutant fraction. These advancements demonstrated a quick, accurate and simple detection and quantitation of PIK3CA mutations in two breast cancer cohorts (first cohort n = 22, second cohort n = 25). Hence this simple, versatile and informative workflow could be applicable for routine diagnostic testing where quantitative results are essential, e.g. disease monitoring subject to validation in a substantial future study