Abstract
Antibiotic resistant strains of bacteria pose a global health threat. Several pathogenic bacteria utilize a type III secretion system (T3SS) to infect their host. T3SSs are needle-like appendages on the bacteria, used to inject the host cell with toxins, which disrupts the cell’s defense. Hence, the T3SS would be a good target for new antibiotic drugs. The goal of this study was to develop a novel method to screen for compounds that inhibit bacterial T3SSs. Yersinia pestis uses a T3SS to cause the bubonic plague and was utilized as the test organism. A disk diffusion assay on Magnesium Oxalate Agar (MOX) was developed to detect inhibitors of T3S. In Yersinia species, low levels of Ca2+ trigger T3S, which simultaneously restricts bacterial growth at 37°C. Therefore, bacteria will grow in smaller, white colonies, which indicate that they are secreting the toxins. In contrast, inhibition of T3S will be indicated by growth of larger, white colonies around the inoculated disk. Disks inoculated with 25μL of dipropionate, a known Y. pestis T3S inhibitor, with concentrations ranging from 0.3μm to 80μm and 25μL water were placed onto MOX agar plates containing 100-200 bacteria and incubated for 48h at 37°C. Cytotoxicity was observed at higher concentrations of dipropionate. However, inhibition of T3S was detected by growth of larger, white colonies around the disks with lower concentrations of dipropionate. Therefore, this method is a simple and inexpensive way to screen for possible compounds that may inhibit T3S secretion.
Faculty Sponsors
Dr. Julie Torruellas Garcia
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-8-2016 1:00 PM
End Date
4-8-2016 5:30 PM
A Novel Method to Screen Drugs that Target Bacterial Type III Secretion Systems
Alvin Sherman Library
Antibiotic resistant strains of bacteria pose a global health threat. Several pathogenic bacteria utilize a type III secretion system (T3SS) to infect their host. T3SSs are needle-like appendages on the bacteria, used to inject the host cell with toxins, which disrupts the cell’s defense. Hence, the T3SS would be a good target for new antibiotic drugs. The goal of this study was to develop a novel method to screen for compounds that inhibit bacterial T3SSs. Yersinia pestis uses a T3SS to cause the bubonic plague and was utilized as the test organism. A disk diffusion assay on Magnesium Oxalate Agar (MOX) was developed to detect inhibitors of T3S. In Yersinia species, low levels of Ca2+ trigger T3S, which simultaneously restricts bacterial growth at 37°C. Therefore, bacteria will grow in smaller, white colonies, which indicate that they are secreting the toxins. In contrast, inhibition of T3S will be indicated by growth of larger, white colonies around the inoculated disk. Disks inoculated with 25μL of dipropionate, a known Y. pestis T3S inhibitor, with concentrations ranging from 0.3μm to 80μm and 25μL water were placed onto MOX agar plates containing 100-200 bacteria and incubated for 48h at 37°C. Cytotoxicity was observed at higher concentrations of dipropionate. However, inhibition of T3S was detected by growth of larger, white colonies around the disks with lower concentrations of dipropionate. Therefore, this method is a simple and inexpensive way to screen for possible compounds that may inhibit T3S secretion.
