There was 5 presentations during the seminar last Friday. And I am going to talk about the first presentation of Jamie Tran. Her presentation was about "Inhibitory effects of iodide, azide, and nitrite ions on photosystem II under illumination."
She start out with an introduction about Photosystem II. In photosystem II, chloride ion was needed to activate the oxygen process in MN-cluster complex, but how? The purpose is to characterize the binding sites of chloride ions on photosytem 2 and to examine how iodide, azide, and nitrite ions donate electrons through MN4CaO5 cluster or Tyrosine.
Her hypothesis was that she thought those ions would reduce the site of oxygen evolution by donating electron.
In the experiment process, she did oxygen evolution assay and evaluate the activity of azide, iodide, and nitrite on NaCl washed PSII under Illumination and in the dark in 5 minute incubation. The result was the irreversible damage by N3, I and NO2 ions.
In the next experiment, it was the process of electron transfer in Tris-washed photosystem 2. The result was that there was electron donation of iodide,nitrite and azide in the dark and under illumination in Tris-washed.
And the last one is about electron donating of Azide without the presence of PSII. The result was that the electron donation of azide was more significant with the presence of the tris-washed PSII under illumination. Also the electron donation of azide occurred similarly regardless if you use Tris-washed in the dark.
Conclusion: The electron transfer to PSII from the anion was absent or very small. The damage occurs within just a few catalyst turnover, so electron transfer is not significant.
Others presentations are:
ReplyDelete1.Alkaloid production of endophytes by Scott. This is a very interesting research about fungal endopytes that can help out the enviroment. The fungal endophytes can help prevent droughts and other environment dangers. They did not find Loline Alkaloids in Sleepy grass because the endophyes do not reproduce alkaloid. However, they did have a good yield of alkaloid with meadow fescue.
2. This one was presented by our admirable SIP leader, Barrett, working with the Petersen Group. The presentation was the synthesis of organic strut for the use in novel semiconductors. There was 3 types of tetracene with di-carboxylic acids. They were trying to form the one with the dicarboxylic acids on the 2nd benzene of the tetracene. They went through diels-alder cycloaddition, hydroxide-promoted hydrolysis of carbonate ester, oxidation of diol via periodinance, and oxidation of dialdehyde to dicarboxylic acid. At the end, everything worked out and they formed the desired tetracene product with little of impurities.
ReplyDeleteAnother one was by Obeth Gutierrez. His presentation was very organize. His research was about atomic absorption spectrometric measurement of in-vivo. His reasearch was followed by 5 steps: optimize GFAAS protocol, acid digestion of organ samples, standard calibration, GFAAS analysis of digested sample, and normalize data. In his result, he found out that GFAAS was a good way to analyze gold content in cellular sample. High dilution might cause analytic problems. He wanted to do more research in the targeted organ, the brain. Asc-NP are retained more effective than pro-NP targeted organ, the brain.
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