Team:TecMonterrey/collab argentina.html


One of the most important parts of science and scientific progress is commonly forgotten by researchers. Working and communication between teams is not only beneficial for both in technical terms, but also opens a bridge that is essential for science; collaboration.

This year we crossed words with a fellow Latin American team. Team: Buenos_Aires started the conversation and our ideas began to flow we talked about how we were achieving hypoxia for our hypoxic promoters characterization and how they were measuring their arsenic sensitive promoters. After some discussion we concluded that we could improve each other’s measurements and agreed to make the collaboration.

When we received the part Team: Buenos_Aires we proceeded with transforming its DNA into Escherichia coli TOP10 chemocompetent cells. Selection of transformants was done with Tetracicline and we continued with a restriction analysis using EcoRI and PstI enzymes. The resulting agarose gel is shown by duplicate in the following pictures.

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After transformants were proven to have the correct plasmid by restriction analysis, we started induction with sodium arsenite. Different concentrations ranging from 0 ppb to 1000ppb were used as induction and measurements were done at 1, 2, 4, 6, 8 hours.

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In each column, 10mL cultures of E.coli transformed with the measurement device were grown until 0.5 OD600. After that, cultures were induced with different concentrations (in ppb) of sodium arsenite. Measurements of RFP fluorescence (AU) and OD600 were taken every time specified in the time (h) column and AU/OD600 is reported. A public water source and water from a nearby lake were also assayed.

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Using the last measured fluoresence/OD600 value plotted against the concentration of arsenite used as inductor, a calibration curve was obtained.

With the use of the newly obtained calibration curve we also measured two samples that we obtained from our neighborhood. We took samples from a nearby lake and from a public water source. Following the same procedure, we grew E.coli cells until .5 OD600 and induced with the samples we obtained (after using a 0.0002 mm syringe microfilter) until 8 hours of induction. After measuring AU/OD600 for 8 hours we obtained the following data:

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Taking the latter into account we might be more careful from where do we have contact with water. These results encourage us to inform the responsible authorities in the future about the current status of the water and have the samples analyzed by an already established method.