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Raheel Anwar Morel Lab

Experiments with Thalassiosira weissflogii (TW) in Relation to Changing Oceanic Carbon Dioxide Concentrations. Raheel Anwar Morel Lab. CO 2 Concentrations and Why They’re Important.

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Raheel Anwar Morel Lab

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  1. Experiments with Thalassiosira weissflogii (TW) in Relation to Changing Oceanic Carbon Dioxide Concentrations Raheel Anwar MorelLab

  2. CO2 Concentrations and WhyThey’reImportant • Thechangingenvironment has ledtohigherdissolvedcabrondioxide concentrations in theworld’soceansdueto global warming and thegreenhouse gas effect • Higher CO2 concentrations,which can easilybeconvertedtobicarobonate, cause changes in the pH oracidity of theworld’soceans

  3. http://switchboard.nrdc.org/blogs/lsuatoni/why_scientists_agree_ocean_aci.htmlhttp://switchboard.nrdc.org/blogs/lsuatoni/why_scientists_agree_ocean_aci.html

  4. The CDCA Enzyme • Cadmiumcarbonicanhydrase • Catalyzestheconversion of CO2 intobicarbonate and viceversa • Cadmiumis a normallytoxic metal, buthere, it can act as a coenzymeforthereaction

  5. Why TW and CDCA? • Knowing where and in what quanitities thisenzymeislocated in the algae is important • Tells ushowthisspecies and otheralgaelikeit can cope with the changing conditions of the oceans • Allow ustoanticipate the effects of future changes

  6. Overview of Work • Studiedtheexpression of the CDCA enzyme in TW underdifferent pH conditions • Isolatedchloroplaststo determine CDCA activity and localization

  7. CDCA Analysis • Looked at TW cells growing under: • High (8.6) • Medium (8.2) and • Low (7.8) pH conditions.

  8. Western Blot

  9. Isolation of Chloroplasts • Developed a procedurefortheisolation of chloroplasts • First, sonicationwasusedto break open cellswithoutentirelydestroyingallthechloroplasts • Cells are resuspended in a buffer designedtoprotectthechloroplaststhat are nowfloating free in thesolution • Solutionisfilteredon a 10 micronfilter, allowing TW cells, most of which are 10 micronorbiggertobecaughtonthefilter, whilechloroplasts, whichnecessarily are smaller, passthrough. • This reduces wholecellcontaminants remarkably • Chloroplasts are thenisolatedon a gradientforfurtheranalysis

  10. MIMS Assay of CDCA activity for Chloroplast Extract • Results showed that CDCA activity was not present in the chloroplasts • Reasons: • CDCA enzyme could be located outside of the chloroplasts • Whole cell activity is ruled out since the pellet of chloroplasts is washed many times • Chloroplasts could get inactivated, but fluroescence microscopy shows only slight decrease in output • Signals from the nucleus may be necessary for CA activity

  11. Conclusions • Overall, higherconcentrations of CDCA are foundwhenthe pH ishigher, givinguscluesonhowalgae in theoceansare effected • Isolation of chloroplastsshowed no signs of CDCA activity

  12. Thanks to • PEI/Grand Challenges • Dr. Yan Xu • Professor Morel

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