Sequenced Alpha-Proteobacterial strains containing GTA gene cassettes and screened for GTA production over time.

<p>The strains screened for this study are indicated in bold type. Maximum abundance of GTA particles observed in parentheses.</p

GTA-mediated gene transfer in the reef environment: RnGTA and NrGTA mediated gene transfer frequencies at a site near Looe Key Reef.

<p>Main figure indicates single antibiotic frequencies and inset indicates double antibiotic frequencies. The asterisk indicates that the viable/culturable counts for that experiment were below the detection limit (200 cfu ml⁻¹) so the frequency was calculated using the calculated detection limit. Note that the frequency calculated in this manner is an underestimate of the actual frequency. Also note, there were no spontaneous double antibiotic revertants at this site.</p

Environmental parameters measured in conjunction with cruise GTA-mediated gene transfer and prophage induction experiments.

<p>Environmental parameters measured in conjunction with cruise GTA-mediated gene transfer and prophage induction experiments.</p

GTA Gene Maps: GTA gene maps from representative, fully sequenced strains used in this study.

<p><i>Rhodobacter capsulatus</i> is the type strain. Strain name in bold indicates a strain that produces putative GTA particles in stationary phase growth. Strain name underlined indicates gene transfer activity of the particles has been demonstrated experimentally. The size of the GTA coding region (kilobase pairs) is indicated in parentheses next to the strain name. The GTA terminase is color-coded black, dark gray indicates GTA genes with identified putative functions, light gray indicates open reading frames with sequence conservation but unknown functions and white indicates host-associated genes (H  =  Host Associated, T  =  GTA terminase, C  =  GTA major capsid, P  =  GTA portal protein, PP  =  GTA pro-head protease, A  =  head-tail adaptor, MT  =  Major tail protein, TF  =  Tail fiber, Hy  =  cell wall hydrolase, SAcT  =  host Serine O-Acetyl transferase).</p

RnGTA-mediated gene transfer experiments at two sites off Jekyll Island, GA: The background is a satellite map of the island with the arrows indicating the sampling sites.

<p>The insets show the single antibiotic gene transfer frequency on the left side of the panel in gray and the double antibiotic gene transfer frequency on the right side of the panel in dark gray. (SpontKanR  =  spontaneous kanamycin revertants; SpontKan-Strep  =  spontaneous kanamycin and streptomycin revertants; GTA-KanR  =  RnGTA GTA treated kanamycin resistance; GTA Kan-Strep  =  RnGTA treated kanamycin and streptomycin resistance).</p

Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill

The Deepwater Horizon oil spill is unparalleled among environmental hydrocarbon releases, because of the tremendous volume of oil, the additional contamination by dispersant, and the oceanic depth at which this release occurred. Here, we present data on general toxicity and mutagenicity of upper water column waters and, to a lesser degree, sediment porewater of the Northeastern Gulf of Mexico (NEGOM) and west Florida shelf (WFS) at the time of the Deepwater Horizon oil spill in 2010 and thereafter. During a research cruise in August 2010, analysis of water collected in the NEGOM indicated that samples of 3 of 14 (21%) stations were toxic to bacteria based on the Microtox assay, 4 of 13 (34%) were toxic to phytoplankton via the QwikLite assay, and 6 of 14 (43%) showed DNA damaging activity using the λ-Microscreen Prophage induction assay. The Microtox and Microscreen assays indicated that the degree of toxicity was correlated to total petroleum hydrocarbon concentration. Long-term monitoring of stations on the NEGOM and the WFS was undertaken by 8 and 6 cruises to these areas, respectively. Microtox toxicity was nearly totally absent by December 2010 in the Northeastern Gulf of Mexico (3 of 8 cruises with one positive station). In contrast, QwikLite toxicity assay yielded positives at each cruise, often at multiple stations or depths, indicating the greater sensitivity of the QwikLite assay to environmental factors. The Microscreen mutagenicity assays indicated that certain water column samples overlying the WFS were mutagenic at least 1.5 years after capping the Macondo well. Similarly, sediment porewater samples taken from 1000, 1200, and 1400 m from the slope off the WFS in June 2011 were also highly genotoxic. Our observations are consistent with a portion of the dispersed oil from the Macondo well area advecting to the southeast and upwelling onto the WFS, although other explanations exist. Organisms in contact with these waters might experience DNA damage that could lead to mutation and heritable alterations to the community pangenome. Such mutagenic interactions might not become apparent in higher organisms for years

Transcriptomic versus biogeochemical data.

<p>Panel A: The correlation between diatom microscope counts and log RuBisCO Form ID transcripts counts. Panel B: The inverse relationship of carbonic anhydrase transcript abundance to DIC concentration. Panel C: The inverse relationship between polyphosphate kinase transcript abundance and phosphate concentration. Station 2 and 25 had little or no phosphate, due to the diatom bloom, however <i>ppk</i> was not upregulated.</p

Sample size-normalized gene counts for the 31 biogeochemically-relevant genes.

<p>Values are the average of the duplicate samples, per 10 million sequences. Bolded/underlined numbers highlight the highest expression for that gene.</p

Metadata for stations sampled in the ARP.

<p>Measurements taken in conjunction with the metatranscriptomes are listed here. Asterisks highlight where concentration of the variable was below limit of detection.</p

Salinity map of the May/June 2010 Amazon River Plume cruise aboard the RV Knorr.

<p>Salinity (PSU) from the underway system along the ship track was augmented with National Oceanographic Data Center profiles in regions of low coverage then interpolated and contoured.</p