1. Kayla Rayford1, Dave Anderson2, Jeneva Anderson2, Karen Guillemin2
Zebrafish isolate Aeromonas alters expression of Vibrio cholera virulence factors
Kayla Rayford1, Dave Anderson2, Jeneva Anderson2, Karen Guillemin2
Bowie State University1, University of Oregon2
Schematic depicting competition between Aeromonas and V. cholerae
V. cholerae and Aeromonas
Introduction
Vibrio cholerae, the causative agent of the highly infectious disease cholera, has resulted in seven pandemics since the beginning of the 19th century.
RNA sequencing was utilized in order to sequence RNA abundance of genes
RNA extraction
cDNA synthesis
Library preparation/tagmenation
Transmission Events Inferred for the Seventh-pandemic Phylogenetic Tree. Digital image. Nature. Nature: International Weekly Journal of Science, 24 Aug Web. 30 July 2015.
V. cholerae ZWU0020 isolate
While it is most commonly known for its role as human pathogen, however, the bacterium also resides in zebrafish gut where it has a commensalist relationship with that host.
There are many well known mechanisms by which V. cholerae is able to effect differences in other co-occurring microbes, such as its type six secretion system (T6SS).
These interactions could possibly alter gene expression in both Vibrio and its co-occurring neighbors.
Together, these types of mechanisms are sometimes referred to as “virulence factors” because they contribute to the process of rapid proliferation and invasion. It could be that the expression of virulence factors is linked to the presence of other species in the microbial community.
Virulence factors are genes that code for molecules and other subcellular components that increase the pathogenicity of an organism
Understanding microbe-microbe interactions reveals how microbes can survive in their environment and cause disease, as well as how the host reacts to these interactions.
Results
Table describes targeted genes expression and function in V. cholerae
Conclusions
V. cholerae ZWU0020 isolate
V. Cholerae ZWU0020 and Aeromonas ZOR0001
Aeromonas ZOR0001 isolate
It is clear that Aeromonas, though eventually outcompeted and effectively absent, nonetheless significantly altered the level of expression for several genes, including two virulence factors.
These genes, cheV-2 and hfq, have been identified as virulence factors due to their role in chemotaxis and RNA binding, respectively.
Conclusively, Aeromonas altered gene expression of virulence factors in Vibrio cholera, and the interactions between different microbial species may be critical factor underlying the molecular causes of virulence.
Objectives
Examine the changes in expression of virulence factors of V. cholerae in the presence of Aeromonas
Compare the levels of virulence factor expression in the presence of V. cholerae bacteria
Elucidate the relationship between V. cholerae and Aeromonas
Snapshots of bacteria illustrate normal growth of both V. cholerae and Aeromonas. The second photograph resembles V. cholerae’s growth patterns because it outcompetes Aeromonas significantly. (These pictures were taken from overnight cultures, incubated in TSA at 30 degrees Celsius.)
Future Directions
Cultivate Vibrio cholerae with other zebrafish bacteria such as Shewanella, Psuedomonas, Plesimonas, etc. and measure expression of virulence factors
Using germ free zebrafish to incubate V. cholerae and Aeromonas and study host response as well as measure gene expression of virulence factors
Conduct similar experiments cross culturing other bacteria: Aeromonas and Shewanella, Shewanella and Psuedomonas, etc.
Materials & Methods
Initial growth rates of several different zebrafish isolates with and without V. cholerae
Selected Aeromonas as bacteria of study; grew with and without V. cholerae
RNA extraction and cDNA of six samples; used RNA seq analysis to measure gene expression
Acknowledgements
Figure 2: Heat map compares gene expression of V. cholerae. Expression 1 illustrates V. cholerae grown as an isolate; expression 2 depicts changes in gene expression as Vibrio co-occurring with Aeromonas.
Figure 1: Bar graph compares numbers of genomic reads of V. cholerae and Aeromonas. Aeromonas comprised a staggering 1% while Vibrio accounted for 91%.
Peter O’Day
Summer Program for Undergraduate Research
META Center for Systems Biology
University of Oregon