2. http://www.mbari.org/molecular/images/EPR%20mussel-map.jpg

3.  First discovered in 1979  Tectonic plates spreading apart and new crust being formed  Precipitate forms chimney- like constructs  Fluids around 350-360°C (662 – 680°F)  The rise of a plume is a function of water column stratification and the strength of the source

4.  Mercury-rich due to cinnabar (HgS) deposits  Vent fluids rich in metal sulfides mix with oxygen-rich, cold water  Low toxicity, low bioavailability  more toxic, more bioavailable  Creates large chemical gradient between vent source and plume http://www.mineralatlas.com/mineral%20photos/C/

5. Atkins et al. 2002

6.  Vestimentiferans, clams & mussels  Harbor symbiotic chemoautotrophic bacteria  Spatially separate acquisition of oxygen and sulfide  Free-living chemoautotrophic bacteria  Thermophiles  Mesophiles  Psychrophiles http://bioweb.uwlax.edu/bio203/s2007/rossing_jaco/images/blacksmoker.jpg http://www.compostinfo.com/images/Tutorial/microbes

7.  First reported in 1960 in Staphylococcus aureus  Unique: only bacterial metal resistance mechanism that transforms its toxic target on a large scale  Efflux pumps or extracellular sequestration most common  merA gene  Mercuric reductase  Organomercury Hg(II)  inert, monoatomic Hg(0) http://www.sacriver.org/images/mercury/figure4.jpg

8.  Collected vent, plume and control samples from EPR 9° N  Isolated and sequenced using 16S for identification http://jb.asm.org/content/vol188/issue24/cover.dtl Alcanivorax http://genome.jgi-psf.org/pseat/pseat.jpg http://microbewiki.kenyon.edu/images/6/64/Coccoid Psychrobacter Pseudoalteromonas

9.  T opt & Hg resistance  Various concentrations of HgCl2 in ASW (0 – 75 μM)  Plume and vent (mesophilic and thermophilic) displayed higher T opt & higher Hg resistance than controls  Hg volatilization  Add HgCl2 to cultures and add to volatilization buffer in microplate

11.  Only four strains were successfully sequenced  1 mesophilic, 3 thermophilic  Phylogenetic analysis revealed a new cluster of merA from thermophilic strains.

12.  Mesophilic and thermophilic strains from the hydrothermal vent region were resistant to mercury, while control psychrophilic strains were sensitive.  New cluster of merA in thermophilic bacteria  Elevated T opt of MR suggests that this enzyme is of thermophilic origin

13.  Should they have tested volatilization in more strains?  Only used EPR3, 6, 7 and 8  Did they support their hypothesis that thermophilic bacteria are the source of the MR in mesophilic bacteria?  Deep-sea vents origin of life?  Evolution of metal resistance in deep-sea vents?  Note to self: How fast does photodegradation occur in shallow waters?

14.  Atkins, M.S., Hanna, M.A., Kupetsky, E.A., Saito, M.A., Taylor, C.D. & Wirsen, C.O. 2002. Tolerance of flagellated protists to high sulfide and metal concentrations potentially encountered at deep-sea hydrothermal vents. Marine Ecology Progress Series. 226:63-75.  Barkay, T., Miller, S.M. & Summers, A.O. 2003. Bacterial mercury resistance from atoms to ecosystems. FEMS Microbiology Reviews. 27:355-384.  German, C.R., Baker, E.T. & Klinkhammer, G. 1995. Regional setting of hydrothermal activity, pp. 3-15. In Parson, L.M., Walker, C.L. & Dixon, D.R. (eds.), Hydrothermal vents and processes. The Geological Society. Geological Society Publishing House, Bath, UK.  Jannasch, H.W. 1995. Microbial interactions with hydrothermal fluids, pp. 273-296. In Humphris, S.E., Zierenberg, R.A., Mullineaux, L.S. & Thomson, R.E. (eds.), Seafloor Hydrothermal Systems; Physical, Chemical, Biological, and Geological Interactions. American Geophysical Union, Washington, DC USA.  Lauro, F.M. & Bartlett, D.H. 2008. Prokaryotic lifestyles in deep-sea habitats. Extremophiles. 12:15-25.  Nakamura, K. & Nakahara, H. 1988. Simplified X-Ray Film Method for Detection of Bacterial Volatilization of Mercury Chloride by Escherichia coli. Applied and Environmental Microbiology. 54(11):2871-2873.  Vetriani, C., Chew, Y.S., Miller, S.M., Yagi, J., Coombs, J., Lutz, R.A. & Barkay, T. 2005. Mercury adaptation among bacteria from a deep-sea hydrothermal vent. Applied and Environmental Microbiology. 71(1):220-226.