Team:Penn/Magnetism

Relationship Between OD600 T2 for AMB-1

We attempted to explore the magnetic properties of AMB-1 as further understanding would prove AMB-1’s value as a chassis in bioremediation and other fields. We hoped to quantify the magnetic strength of AMB-1 using spin-spin relaxation time (T2 time) and relate it to the cell concentration (OD600). To do so, we used a magnetic NMR machine (the minispec mq60, Bruker) to measure the T2 decay time of cell samples. A longer T2 time indicated fewer magnetic particles, and therefore weaker magnetic properties. Since the relationship between the inverse of T2 and OD was linear, this data supports that each cell has roughly the same number of magnetosomes, and that a greater number of these magnetosomes can be correlated with stronger magnetic properties.

AMB-1 was grown under anaerobic conditions to saturation. The culture was then serially diluted into ½, ¼ and 1/8 of the initial concentration. The OD600 and T2 time of all dilution samples was measured and then recorded in the table below (Table 4.1). One 1 mL of the cell sample was used for each measurement. MSGM media that does not contain bacteria was used as a blank for this experiment (the OD600 for the blank is 0).

Achievement:

The cell concentration and magnetic strength showed a linear relationship (1T2 =0.0032x + 0.0015) with an R^2 value that was very close to one.