Skip to main content Skip to navigation
The Gene and Linda Voiland School of Chemical Engineering and Bioengineering

Research of Nehal I. Abu-Lail

How Do Food-Borne Bacteria Respond to Stress?

⬅ Back to Dr. Abu-Lail’s List of Research Projects

Problem

As super bugs, bacteria are capable of multiplying, adhering and causing diseases in harsh environmental conditions of pH, ionic strength and temperature.

Goal

Quantify the nanoscale forces and types that govern bacterial cells’ interactions to model surfaces of interest under stress.

Impact

Bacterial adhesion can be controlled.

Figure

Stress caused by: pH of 4-9, Temperature of 4-40 degrees Celsius, Ionic strength 0-1 M NaCl
Graph showing adhesion energy for growth temperatures - the highest adhesion energy at 30 degrees C
Graph showing specific and nonspecific Force as it corresponds to pH
Graph showing Total soft-particle DLVO energy in relation to distance (nm) - The lowest energy barrier to adhesion at 30 degrees C
Graph showing force as it corresponds to distance

Questions:

  • Are the physiochemical properties of microbes conserved among strains of a given species or not?
  • Can nonpathogenic food-borne bacteria that share similar genetics with FBBP be used as surrogates to investigate FBBP?
  • How heterogeneous are the physiochemical properties of FBBP?
  • How different are FBBP from nonpathogenic food-borne bacteria in their adhesion?

Research Details

The Centers for Disease Control and Prevention (CDC) report that every year more than 5 million illnesses result in the United States from food-borne bacterial pathogens (FBBP), costing up to $7 billion of medical expenses and industrial losses. Many of these FBBP are the causative agents of potentially lethal infections. Consumption of contaminated food by FBBP is believed to be the first key step in their route to infections. FBBP can contaminate food while growing in soil, during food processing as well as during food storage. Most FBBP can colonize, multiply and persist on many surfaces in the food industry environments, and survive in harsh conditions such as those often encountered during food processing. Example harsh conditions are severe acidic or basic chemical stresses, extremely salty environments as well as refrigeration temperatures. Even though bacteria are able to survive in such environments, the mechanisms by which they are able to do that are largely unknown.

Atomic force microscopy (AFM) can provide a unique tool to explore the mechanisms by which bacteria adapt to stress. Examples of what AFM is capable of addressing include detailing how bacterial surfaces manipulate their physiochemical properties of charge, wettability and elasticity at the single cell level in response to stress. In addition, AFM can enable the quantification of how bacterial cells change the composition as well as the localization of key proteins on their surfaces in response to stress. Furthermore, with AFM, we can investigate whether variable FBBP respond in a similar manner to stress or not.

In our lab, we would like to answer questions like: 1) are the physiochemical properties of microbes conserved among strains of a given species or not? 2) can nonpathogenic food-borne bacteria that share similar genetics with FBBP be used as surrogates to investigate FBBP? 3) how heterogeneous are the physiochemical properties of FBBP? and 4) how different are FBBP from nonpathogenic food-borne bacteria in their adhesion? The approach and analyses we apply to FBBP can be transferred to other types of bacteria.

Funding Acknowledgements

NSF - National Science Foundation 3M NIH National Institute of Allergy and Infectious Diseases