A Study Quantifying Stress-Induced Transcripts in Magnesium Bentonite Treated Bacteria

Friday, February 17, 2017
Exhibit Hall (Hynes Convention Center)
Meghana Nadella, Allen High School, Allen, TX
Antibiotics have been heralded as some of the greatest scientific discoveries of all times. Despite their success in preventing and treating bacterial infectious diseases in recent years there has been a significant increase in continuous antibiotic exposure, overuse, and misuse. These situations have caused great acceleration in bacterial resistance to antibiotics, threatening our ability to treat common bacterial infectious disease, worsening clinical outcomes and stretching health care resources. Many species of drug resistant bacteria such as XDR TB, MRSA, and STEC highlight the need for developing new and alternative methods of combating antibiotic resistance. With aims to achieve this goal, experiments explored the antibacterial properties of natural healing clays.

Using bacterial growth inhibition assays, six types of clays were screened for potential antibacterial activity against gram-negative bacteria E. coli. Of the six clays investigated, Magnesium Bentonite Clay inhibited bacterial growth with highest efficacy. Next, the mechanisms by which clay mediated its antibacterial effect was explored. Three experiments were conducted demonstrating that antibacterial activity of Magnesium Bentonite was largely independent of divalent metal ions, consisting of soluble elements, and that Magnesium Bentonite was also effective against gram-positive bacteria.

In order to elucidate the molecular mechanism of by which Magnesium Bentonite inhibited bacterial growth, transcriptional changes in bacteria was screened for. E. coli and Staph. epidermidis cultures were exposed to Magnesium bentonite. Bacterial cells were collected after 3 and 24 hour intervals and the RNA was purified. Then transcripts involved in stress response and death-related markers were compared using Quantitative polymerase chain reaction (qPCR). Analysis of results indicated that Magnesium Bentonite increased stress and stress related response in cells relative to control. An increase in YJBJ and PSTS genes and a decrease in treC and PROW genes show an increase in stress response and a decrease in cellular respiration respectively. These findings suggest that bacterial growth inhibition by Magnesium Bentonite Clay is associated with cell stress and death. It is interesting to note that prior research has implicated genes growth inhibition to genes involved with NaCl and Fe molecules.

These findings raise many questions, and set the stage for future research. A possible association between the materials in the clay and their effect on the various stress response genes could unravel the molecular mechanism in growth inhibition, while revealing potential new antibacterial drug targets. Future experimentation would be geared towards identifying the active component in Magnesium Bentonite clay through the use of mass spectroscopy. In summary, this work identifies Magnesium Bentonite Clay as an effective source for bacterial growth inhibition property, and has potential in the world’s war against superbugs.