Supervisors: A/P Gan Yunn Hwen, A/P Too-Heng Phon
MicroRNAs are short non-coding RNA molecules that are evolutionarily conserved in many species and play many roles which includes controlling the fate of immune cells, regulating target genes, responding to stimulatory cues, and enhancing immune responses to antigens. They are implicated in both normal physiological and pathological processes in humans such as cancer, pregnancy, and infectious diseases. Consequently, researchers have attempted to use miRNAs as biomarkers to diagnose different cancers, pregnancy disorders, and microbial infections. Recent research on the potential of miRNAs to diagnose infections have largely focused on using animal models and cell lines to model viral and parasitic infections. In this proof-of concept pilot study, we infected human blood or peripheral blood mononuclear cells (PBMCs) with Gram-negative, Gram-positive bacteria, or lipopolysaccharide (LPS) and examined changes in expression of six miRNAs. We observe that miR-155 is upregulated in both PBMC pellet and supernatant following stimulation with Gram-negative bacteria or LPS, but not in PBMC pellet following infection with Gram-positive bacteria. The ability to detect changes in miRNA expression in PBMC supernatant circumvents additional manipulation of cells, and this is significant as there have been no studies in literature reporting the detection of human miRNAs in PBMC supernatant. The findings from this study can be used towards the development of the first miRNA-based diagnostic kit that can distinguish between different types of bacterial infections in blood plasma or extracellular fluid.
The honours thesis can be found archived here.
The poster can be found archived here.
Supervisor: Dr. Edmund Low
Interdisciplinary education has been increasingly promoted in undergraduate education as attempts to impart teamwork, problem solving, and critical thinking skills that are essential in today’s knowledge economy. However, while these goals are laudable, there is little available research on how best to structure these interdisciplinary opportunities such that goals are met. In this study, we focus on a historically fragmented field, the sciences, and explore interdisciplinary education at both a philosophical and an empirical level through literature reviews, interviews, and surveys. Our results suggest that students are broadly satisfied with the interdisciplinary education of University Scholars Programme (USP) Science and Technologies (S&T) modules, but problems with appeal may cause certain modules to have more homogenous classes.
The independent study thesis can be found archived here.
Supervisor: Prof. Peggy Cotter
Burkholderia thailandensis is frequently used as a model for other Burkholderia species that infect humans and cause diseases. Living in sociomicrobial communities, B. thailandensis identify neighboring microbes via a Two Partner Secretion pathway, developing complex strategies for competing and cooperating with one another. This pathway involves the translocation of exoprotein BcpA using an outer membrane channel-forming protein BcpB. B. thailandensis distinguishes between “self” and “non-self” neighbors on the basis of BcpA catalytic activity. Without cognate BcpI, toxic BcpA kills the “non-self” bacterium via Contact-Dependent Inhibition. If neighbors produce cognate BcpA and BcpI that complex together, they are recognized as “self” and Contact-Dependent Signaling occurs. This results in cooperative phenotypes such as aggregation, pigment production, and Congo Red binding. Our work aims to identify potential regulators of these cooperative phenotypes. Firstly, transposon Tn5 is transferred into B. thailandensis via conjugation and inserts into a gene that may downregulate expression of the lacZ reporter and change expression of cooperative phenotypes. Next, nested arbitrary primed PCR is used to determine location of transposon insertions. In experiments conducted, the transposon was shown to insert into lacZ, but no other gene was identified. The use of fresh primer stocks, confirming the presence of Tn5 insertion, and obtaining DNA from colonies did not improve the arbitrary PCR process. It is possible that the genes disrupted by transposon insertion are inaccessible to the arbitrary primers. Alternative methods such as inverse PCR and plasmid rescue, with the use of different transposons, may be considered in future experiments.
On completion of two summer terms of research, a poster presentation is required. The final poster can be found archived here.