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Luisa Hiller, PhD

Graduation Year: 2005
Advisor: Haldar
Current Position: Eberly Family Career Development Associate Professor of Biological Sciences, Carnegie Mellon University

Dr. Luisa Hiller is a native of Sao Paolo, Brazil.  She did her undergraduate degree at Pomona College in Claremont, California before coming to Northwestern for graduate school.  She did her thesis in the lab of Katsuri Haldar in the Department of Microbiology-Immunology.  Luisa is currently the Eberly Family Career Development Associate Professor of Biological Sciences at Carnegie Mellon University.

What made you want to go to graduate school?

Once I learned about evolution and molecular biology I was hooked – I wanted to explore biological problems. During college I took a month-long camping trip in the northeast of Brazil, where I gathered my own collection of personal parasites. After that, I wanted to study microbiology.

What brought you to Northwestern and the IGP/DGP?

Parasitology. I wanted to study malaria with Kasturi Haldar. The magnificent lakefront in downtown Chicago was an added bonus.

What did you study in graduate school?

I studied the interactions between the malarial parasite, Plasmodium falciparum, and its host, the human red blood cell. Using motif identification algorithms, we discovered a widespread, but previously unidentified, host-targeting signal in malarial proteins. In silico searches of the malarial genome using this motif enabled us to characterize a novel secretome associated with malarial infection that vastly expanded the pool of malarial drug targets.  This discovery suggested that the parasite induces complex molecular changes in the host and revealed candidate effectors.

What did you study in your postdoc?

During my postdoctoral training with Dr. Garth Ehrlich, I continued to combine microbiology and genomics to study microbial pathogenesis. We characterized the genomic variability within the S. pneumoniae species and the degree of plasticity of the S. pneumomiae genome during chronic infections. Perhaps my favorite project at this time was an investigation of the tempo and relevance of horizontal gene transfer to S. pneumoniae strain evolution during naturally occurring chronic infections. This project made use of a set of clinical strains, isolated over a 7-month period, from a single child who suffered from a series of chronic and recurring upper respiratory infections.  Whole genome sequence comparisons of all strains captured an unprecedented degree of gene transfer. Isolates showed a progressive accumulation of recombinations, such that a large percentage of the genome (over seven percent of the dominant lineage) was recombined over the course of this single infection.  We identified not only the major parental strain and the recombinant, but also the DNA donor, thus allowing the reconstitution of in vivo recombination events. This study led to the hypothesis that S. pneumoniae’s genome plasticity has evolved as a mechanism to cope with the host's immune response and variability and provides a means by which this species evades vaccines and antibiotics.  

What are your current research interests? 

My lab members and I study how microbes make you sick. To answer this question we examine microbial molecular mechanisms associated with disease. We study the bacterial pathogen Streptococcus pneumoniae (pneumococcus), a major human pathogen and the main cause of lower respiratory infections worldwide. Pneumococcus is ideal for the study of molecular mechanisms of disease because it can be commensal or pathogenic. In its commensal form, it asymptomatically colonizes the human nasopharynx; while in its pathogenic form, it disseminates to tissues and causes mild or severe disease. The molecular basis of the pathogenic lifestyle is poorly understood and is at the core of our research.

How have they changed over time? 

I moved from eukaryotic microbes to prokaryotic microbes – but always with a focus on the interface between the microbe and its host. 

How did Northwestern prepare you for your current career?

I could not have imagined a better mentor than Kasturi Haldar. She not only taught me techniques and facts, she taught me how to approach scientific questions and take responsibility for my science. She is still one of my role models.  

What is the most rewarding part of your job?

Uncovering previously unknown biological processes together with trainees.

What is the most challenging part of your job?

Making sure that everyone in the lab is funded and in a healthy environment.

What advice would you give to current students interested in pursuing careers in academics?

Believe your data (while making sure you have the necessary controls).

Any final advice for students?

Science should be fun!

 

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