2024 AIChE Annual Meeting

DNA Based Biosensors for Horizontal Gene Transfer Detection

Horizontal gene transfer (HGT), one of the mechanisms used by bacteria to transfer genetic information between themselves, occurs in all microbial environments, and is one of the primary causes of the dissemination of antibiotic resistance among bacterial populations. Typical methods of tracking HGT typically involve the introduction of antibiotic-resistant genes and genes that code for fluorescent proteins. Although feasible in a controlled laboratory environment, these methods are time-consuming and cumbersome to perform. Fluorescently-tagged aptamers offer an alternative method of quantifying HGT without the need for the introduction of new plasmids. The development of other methods that could quantify bacteria in-situ and allow for high-throughput screening of bacteria would be greatly beneficial for the study of horizontal gene transfer in bacteria.

DNA aptamers are oligomers composed of nucleic acids that have been shown to be able to selectively bind to certain targets. Via a method known as SELEX (systematic evolution of ligands by exponential enrichment), selectively binding aptamers can be produced via an iterative process. The ability of aptamers to bind selectively to a wide range of targets makes them a possible candidate for detecting horizontal gene transfer. The successful development of aptamers would allow for the observation of horizontal gene transfer in bacterial populations, and allow quantification via high-throughput techniques such as flow cytometry.

Replication of literature results for aptamer binding to bacteria has shown that aptamer binding is highly sensitive to the conditions they were involved in. To find aptamers that are suitable for use in screening for horizontal gene transfer may necessitate the need to modify the SELEX procedure to encourage the enrichment of DNA aptamer candidates that are not as sensitive to environmental conditions. More iterations of the SELEX procedure will need to be performed in order to properly evaluate the viability of aptamers as candidates for detecting horizontal gene transfer.