Antibiotics are present in nearly every facet of our lives including personal hygiene, medicine, food processing, and the treatment of infectious diseases. Because of this widespread exposure, antibiotic resistance occurs in dangerous pathogens around the world. Novel antibiotics are needed to combat these resistant organisms and reduce both the loss of lives and treatment costs. Most antibiotics originated in microorganisms cultured from soil, but very few novel compounds have been discovered in this environment over the last several decades. It is imperative that other environments are screened for antibiotic producing microbes. We sampled the Puget Sound, isolating and culturing bacteria from the surface. Isolated cultures were tested against reference strains of common pathogens for antibiotic potential by measuring the zones of inhibition they produced via agar diffusion. Phylogenetic analysis with 16s ribosomal RNA was used for identification of cultures with inhibitory activity. This type of analysis, especially if scaled-up, has potential to identify novel therapeutic compounds that may elude common resistance mechanisms.

The rise of multidrug resistant bacteria necessitates finding alternative therapies against bacterial pathogens. Virulence in many pathogenic bacteria are predicated on their ability to communicate and act in unison. In a phenomenon known as quorum sensing (QS), a threshold mass of bacterial cells produces an amplified chemical signal that triggers the collective expression of a new phenotype, such as enhanced virulence. Therefore, inhibiting QS, without preventing cellular growth, may be a recourse against drug resistant bacteria. Marine invertebrates found in warmer waters, such as the Australian reef and Indian Ocean, have shown quorum sensing inhibitory (QSI) potential. However, most marine invertebrates in the Pacific Northwest’s Puget Sound have not previously been screened for QSI compounds. This research presents the findings for QSI sources among Puget Sound’s marine sponges and tunicates, using a bacterial reporter strain to screen for QSI activity. We used the reporter strain Chromobacterium violaceum (ATCC 12472), which uses the QS signal n-Acyl-homoserine lactone (AHL) to produce its purple pigment. QSI activity was screened for by overlaying the reporter strain with a sponge or tunicate sample. Subsequent absence of pigment in the indicator strain suggested the presence of a QSI compound. Promising compounds were then extracted and identified using analytical techniques. These results help expand the catalogue of known QSI molecules from marine sources, advancing potential therapies against existing and future antibiotic resistant pathogens.

Seattle’s Combined Sewer Overflow (CSO) system discharges approximately 100 million gallons of untreated sewage and storm water runoff into its waterways annually. The sewer system includes two combined waste streams: waste from sewer basins, which captures storm water runoff, and wastewater from buildings and industry. Pollutants in the effluent such as human waste, automotive by-products, pesticides, and pharmaceuticals can degrade ecosystems. To determine the impact that CSO outfalls have on Seattle’s waterways, this study tested for pollutant levels in sediment near two discharge areas: Elliott Bay and the western end of Seattle’s Ship Canal. Sediment samples were collected using a Van Veen grab, then handled and stored using sterile, inert materials to avoid contamination. Sediments were tested for heavy metals including mercury, via cold-vapor atomic absorption, and lead, via inductively coupled plasma mass spectrometry. The organic pollutants ammonia, nitrate, and phosphate were quantified via automated calorimetry. Laboratory testing for pollutants was done in accordance with EPA guidelines or standard analytical methods. Results were compared to the Washington Department of Ecology’s Sediment Management Standards. Preliminary results suggest that lead and mercury levels do not exceed the Department of Ecology’s sediment quality standards, while cadmium levels are slightly above or below recommended levels at each site. This data can be used as a baseline to help better understand the contribution of CSOs to pollution levels in these areas. More research will be necessary to determine the extent of damage to ecosystems near the outfalls.

Amnesic shellfish poisoning is the result of eating seafood contaminated with domoic acid, produced by toxigenic diatom species from the genus Pseudo-nitzschia. In the summer of 2015, abnormally large assemblies, known as super chains, of Pseudo-nitzschia australis appeared in the massive algal bloom that swept up the Pacific Coast. This affected commercial and recreational shellfish harvesting and cost millions of dollars in shellfish sales. Due to their recent appearance, knowledge of P. australis super chains is extremely limited. Here, we investigate the prevalence of super chains in Puget Sound and along the Pacific Coast. The deep chlorophyll maximum, DCM, is a layer in the water column that is often found to contain a high volume of photosynthesizing phytoplankton.  A collection of electronic devices that measure conductivity, temperature, and depth (also called CTD) was deployed to determine DCM, from which plankton samples were collected. Scanning electron and light microscopy were used to identify P. australis species and to examine the morphology of their associated bacteria. Most surveys have been conducted during the late summer when blooms are at their peak. By conducting our survey in the late winter, we have had the opportunity to measure P. australis super chain prevalence during what is typically a less active season. Our results provide novel information of P. australis super chains and their associated bacteria during a season that has been so far neglected. In addition, our diverse sample sites in Puget Sound and along the West Coast present a systematic survey and allow us to make regional comparisons. This study lays a foundation for more comprehensive research of super chains in the future.