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In the Northeast USA, the aquaculture of macroalgae is a rapidly growing industry. Within this region, there are no established regulations for farm siting or methods of pathogen detection on macroalgae cultivated or harvested for human consumption. Bacterial pathogens from natural and anthropogenic sources may persist in coastal waters and can potentially contaminate macroalgae. During the winter growing season, sugar kelp Saccharina latissima and adjacent water were sampled from three sites of kelp aquaculture located in adjacent bays of ME, USA. Membrane filtration onto selective media detected Escherichia coli, Vibrio parahaemolyticus, and Vibrio alginolyticus in kelp and water samples at all sites, however plate counts were very low. The foodborne pathogens Salmonella enterica ser. Typhimurium, V. parahaemolyticus, and enterohemorrhagic E. coli O157:H7 were detected on enriched kelp samples from 83%, 78%, and 56% of sampling events, respectively, using molecular methods. Even with low bacterial levels, this frequency of detection confirms the risk of foodborne pathogens present on kelp and recommends the development of best management practices to control microbial growth during kelp harvest and processing. Bacterial plate counts from kelp samples often varied from those of water, indicating the importance of sampling the kelp directly, and that the association between bacterial pathogens on kelp and in the surrounding water should be further investigated. This study provides the first food safety assessment of sea vegetables in this region with the goal of providing data to enable the expansion of its industry.

Culture experiments were conducted on ten phytoplankton species to examine their biological and physiological responses during exposure to oil and a combination of oil and dispersant. The species tested included a range of taxa typically found in the Gulf of Mexico such as cyanobacteria, chlorophytes, and diatoms. Cultures were exposed to Macondo surrogate oil using the water accommodated fraction (WAF), and dispersed oil using a chemically enhanced WAF (CEWAF) and diluted CEWAF, to replicate conditions following the Deepwater Horizon spill in the Gulf of Mexico. A range of responses were observed, that could broadly class the algae as either "robust" or "sensitive" to oil and/or dispersant exposure. Robust algae were identified as Synechococcus elongatus, Dunaliella tertiolecta, two pennate diatoms Phaeodactylum tricornutum and Navicula sp., and Skeletonema grethae CCMP775, and were largely unaffected by any of the treatments (no changes to growth rate or time spent in lag phase relative to controls). The rest of the phytoplankton, all centric diatoms, exhibited at least some combination of reduced growth rates or increased lag time in response to oil and/or dispersant exposure. Photophysiology did not have a strong treatment effect, with significant inhibition of photosynthetic efficiency (Fv /Fm ) only observed in the CEWAF, if at all. We found that the effects of oil and dispersants on phytoplankton physiology were species-dependent, and not always detrimental. This has significant implications on how oil spills might impact phytoplankton community structure and bloom dynamics in the Gulf of Mexico, which in turn impacts higher trophic levels.

Ongoing bioremediation research seeks to promote naturally occurring microbial polycyclic aromatic hydrocarbon (PAH) degradation during and after oil spill events. However, complex relationships among functionally different microbial groups, nutrients and PAHs remain unconstrained. We conducted a surface water survey and corresponding nutrient amendment bioassays following the Texas City "Y" oil spill in Galveston Bay, Texas. Resident microbial groups, defined as either heterotrophic or autotrophic were enumerated by flow cytometry. Heterotrophic abundance was increased by oil regardless of nutrient concentrations. Contrastingly, autotrophic abundance was inhibited by oil, but this reaction was less severe when nutrient concentrations were higher. Several PAH compounds were reduced in nutrient amended treatments relative to controls suggesting nutrient enhanced microbial PAH processing. These findings provide a first-look at nutrient limitation during microbial oil processing in Galveston Bay, an important step in understanding if nutrient additions would be a useful bioremediation strategy in this and other estuarine systems.

The processes preceding the detachment of cytochrome c (cyt c) from the inner mitochondrial membrane in intrinsic apoptosis involve peroxidation of cardiolipin (CL) catalyzed by cyt c-CL complex. In the present work, we studied the effect of 17 dietary flavonoids on the peroxidase activity of cyt c bound to liposomes. Specifically, we explored the relationship between peroxidase activity and flavonoids' (1) potential to modulate cyt c unfolding, (2) effect on the oxidation state of heme iron, (3) membrane permeability, (4) membrane binding energy, and (5) structure. The measurements revealed that flavones, flavonols, and flavanols were the strongest, while isoflavones were the weakest inhibitors of the oxidation. Flavonoids' peroxidase inhibition activity correlated positively with their potential to suppress Trp-59 fluorescence in cyt c as well as the number of OH groups. Hydrophilic flavonoids, such as catechin, having the lowest membrane permeability and the strongest binding with phosphocholine (PC) based on the quantum chemical calculations exhibited the strongest inhibition of Amplex Red (AR) peroxidation, suggesting a membrane-protective function of flavonoids at the surface. The results of the present research specify basic principles for the design of molecules that will control the catalytic oxidation of lipids in mitochondrial membranes. These principles take into account the number of hydroxyl groups and hydrophilicity of flavonoids.

Trait-based ecology, which focuses on using the traits of species and individuals to understand ecology (from populations to ecosystems), is becoming an increasingly productive and widely employed paradigm. To date, trait-based approaches have been used to study taxa from microbes to megafauna in every major area of aquatic ecology yielding exciting results. However, this promising field faces a number of significant obstacles, including: (1) identifying and measuring ecologically relevant traits, (2) integrating inter- and intra-specific trait variation, (3) detecting and quantifying trait correlations and trade-offs, and (4) accounting for the context dependency of traits. These issues are often particularly acute for specific taxa or systems. This paper highlights these looming challenges, as well as ways to address them. Proposed solutions center around using new technologies to collect trait data, coordinating research efforts, and curating and sharing data. Throughout, we take an interdisciplinary approach, sharing examples spanning a wide range of aquatic taxa and systems. It is our hope that this paper will stimulate frank discussions and help the growing field of trait-based aquatic ecology maximize its potential.

Therapeutic drugs and environmental pollutants may exhibit high reactivity toward DNA bases and backbone. Understanding the mechanisms of drug–DNA binding is crucial for predicting their potential genotoxicity. We developed a fluorescence analytical method for the determination of the preferential binding mode for drug–DNA interactions. Two nucleic acid dyes were employed in the method: TO-PRO-3 iodide (TP3) and 4′,6-diamidino-2-phenylindole (DAPI). TP3 binds DNA by intercalation, whereas DAPI exhibits minor groove binding. Both dyes exhibit significant fluorescence magnification on binding to DNA. We evaluated the DNA binding constant, Kb, for each dye. We also performed fluorescence quenching experiments with 11 molecules of various structures and measured a C50 value for each compound. We determined preferential binding modes for the aforementioned molecules and found that they bound to DNA consistently, as indicated by other studies. The values of the likelihood of DNA intercalation were correlated with the partition coefficients of the molecules. In addition, we performed nuclear magnetic resonance (NMR) studies of the interactions with calf thymus DNA for the three molecules. The results were consistent with the fluorescence method described above. Thus, we conclude that the fluorescence method we developed provides a reliable determination of the likelihoods of the two different DNA binding modes.

Studies show that tricyclic antidepressants prescribed for migraines, anxiety, and child enuresis have numerous adverse effects in living cells. One of the undesired outcomes observed under treatment with these drugs is DNA damage. However, the mechanisms underlying damage have yet to be elucidated. We performed in vitro studies of the DNA damage caused by four tricyclic antidepressants: imipramine, amitriptyline, opipramol, and protriptyline. We focused particularly on the DNA damage aided by peroxidases. As a model of a peroxidase, we used horseradish peroxidase (HRP). At pH 7, reactions of HRP with excess hydrogen peroxide and imipramine yielded an intense purple color and a broad absorption spectrum with the maximum intensity at 522 nm. Reactions performed between DNA and imipramine in the presence of H(2)O(2) and HRP resulted in the disappearance of the DNA band. In the case of the other three drugs, this effect was not observed. Extraction of the DNA from the reaction mixture indicated that DNA is degraded in the reaction between imipramine and H(2)O(2) catalyzed by HRP. The final product of imipramine oxidation was identified as iminodibenzyl. We hypothesize that the damage to DNA was caused by an imipramine reactive intermediate.