Experience

SEATTLE CHILDRENS RESEARCH INSTITUTE
• United States
• Hospitals and Health Care
• 1 - 100 Employee
• Senior Scientist

  • Nov 2021 - Present


UCSF

• United States
• Higher Education

• Scientist-Protein Glycosylation & Antibiotic Resistance

  • May 2012 - Dec 2020

  Administered end-to-end functional characterization of the biosynthesis of the serine-rich repeat (SRR) bacterial glycoproteins (a family of adhesins important for virulence), leading to the discovery of antimicrobial targets preventative of bacterial colonization. Implemented enzymatic characterization strategies of glycosylation components uncovering new modification steps involved in SRR modification. Worked cross functionally, introducing mutations in enzyme components via strain… Show more Administered end-to-end functional characterization of the biosynthesis of the serine-rich repeat (SRR) bacterial glycoproteins (a family of adhesins important for virulence), leading to the discovery of antimicrobial targets preventative of bacterial colonization. Implemented enzymatic characterization strategies of glycosylation components uncovering new modification steps involved in SRR modification. Worked cross functionally, introducing mutations in enzyme components via strain engineering techniques, Mass Spectrometry (MS) profiling of engineered glycoforms and assessing bacteria-host interactions to reveal a glycan regulatory modification (O-acetylation) required for generating an adhesin glycoform optimized for host attachment. Coordinated a multi-institute consortium to identify a mechanism of daptomycin resistance (DapR) among streptococci. Collaborated with NGS facilities to genome sequence antibiotic strains. Led strategies in assessments of individual gene function towards antibiotic resistance. Strain characterization of DapR isolates (mutation identification, strain engineering & phenotypic analysis) uncovered a novel mechanism of bacterial lipid remodeling preventative of daptomycin binding. Scientific accomplishments: ● Established collaborations and managed projects with MS & glycobiology laboratories to identify enzymatic pathways required for the glycosylation of bacterial virulence determinants. Developed enzyme function characterization assays of undefined glycosylation components, revealing a new sequence of events for an O-glycosylation of bacterial virulence factors. ● Discovered a conserved glycan regulatory modification among Gram-positive pathogens essential for producing glycosylated adhesins optimized for bacterial-host binding. ● Developed strain characterization methodologies of antibiotic resistant isolates with clinicians and scientists to uncover a Streptococcal lipid remodeling mechanism conferring daptomycin resistance.

• Postdoctoral Researcher - Protein Secretion mechanisms in Gram-positive bacteria

  • Apr 2006 - Apr 2012

  Defined a mechanism of glycoprotein transport carried out by the accessory Sec (aSec) protein secretion system, a specialized bacterial glycoprotein transporter. Developed protein-interaction methods to characterize protein interactions among aSec components required for protein transport via Yeast 2 hybrid, co-IP & biophysical analysis (Isothermal Titration Chemistry, ITC), in combination with in vivo mutant complementation. Uncovered bifunctional roles of aSec proteins involved in both export… Show more Defined a mechanism of glycoprotein transport carried out by the accessory Sec (aSec) protein secretion system, a specialized bacterial glycoprotein transporter. Developed protein-interaction methods to characterize protein interactions among aSec components required for protein transport via Yeast 2 hybrid, co-IP & biophysical analysis (Isothermal Titration Chemistry, ITC), in combination with in vivo mutant complementation. Uncovered bifunctional roles of aSec proteins involved in both export & glycosylation processes. Developed structure function studies of aSec components to reveal a bifunctional role of the aSec transporter, facilitating both a post translational modification and protein export. Developed biophysical analysis (ITC) of SRR binding to host ligands including ECM proteins and sugars to determine the molecular basis of streptococcal-host binding. ● Secured independent funding (AHA fellowship) for my own research on protein secretion in Gram positive bacteria. ● Mapped a network of protein-protein interactions within the aSec system essential for glycoprotein transport. ● Resolved the structure & enzymatic mechanism of a novel bacterial 2-protein O-glycosyltransferase complex. ● Recognized the aSec bacterial secretion system is a bi-functional transporter, mediating a post-translational modification in addition to protein secretion. ● Characterized the molecular basis of binding between human fibrinogen and the SRR glycoproteins of the neonatal pathogen, Group B streptococcus.



Seattle Children's

• United States
• Hospitals and Health Care
• 700 & Above Employee

• Postdoctoral Fellow – Defining RNA polymerase function towards Streptococcal virulence.

  • Feb 2003 - Jan 2006

  Defining RNA polymerase (RNAP) function towards streptococcal virulence. • Developed multi-stage HPLC separations of RNAP complexes isolated from Bacillus subtilis and Group B streptococcus (GBS) to identify novel RNAP protein components. • In collaboration with the institute of genome research (TIGR), analyzed gene expression profiles (micro array) and carried out qRT-PCR and promoter mapping to assess the impact of RNAP subunits on global gene-expression. • Identified the delta… Show more Defining RNA polymerase (RNAP) function towards streptococcal virulence. • Developed multi-stage HPLC separations of RNAP complexes isolated from Bacillus subtilis and Group B streptococcus (GBS) to identify novel RNAP protein components. • In collaboration with the institute of genome research (TIGR), analyzed gene expression profiles (micro array) and carried out qRT-PCR and promoter mapping to assess the impact of RNAP subunits on global gene-expression. • Identified the delta protein of RNAP as an important modulator of streptococcal virulence gene expression. Show less Defining RNA polymerase (RNAP) function towards streptococcal virulence. • Developed multi-stage HPLC separations of RNAP complexes isolated from Bacillus subtilis and Group B streptococcus (GBS) to identify novel RNAP protein components. • In collaboration with the institute of genome research (TIGR), analyzed gene expression profiles (micro array) and carried out qRT-PCR and promoter mapping to assess the impact of RNAP subunits on global gene-expression. • Identified the delta… Show more Defining RNA polymerase (RNAP) function towards streptococcal virulence. • Developed multi-stage HPLC separations of RNAP complexes isolated from Bacillus subtilis and Group B streptococcus (GBS) to identify novel RNAP protein components. • In collaboration with the institute of genome research (TIGR), analyzed gene expression profiles (micro array) and carried out qRT-PCR and promoter mapping to assess the impact of RNAP subunits on global gene-expression. • Identified the delta protein of RNAP as an important modulator of streptococcal virulence gene expression. Show less



Provalis Plc

• United Kingdom
• Pharmaceutical Manufacturing

• Industrial Scientist – Development of Lactococcus lactis as a Live Bacterial Therapeutic.

  • Jan 2002 - Oct 2002

  As an industrial scientist within the vaccine development division of Provalis Plc, I was tasked with engineering strains of Lactococcus lactis to surface express pneumococcal vaccine antigens, with the scientific objective of developing a live vaccine protective against pneumococcal infection. • Gram-positive expression vectors were constructed for heterologous expression of streptococcal surface proteins. • Developed animal models of immunization and bacterial challenge to assess… Show more As an industrial scientist within the vaccine development division of Provalis Plc, I was tasked with engineering strains of Lactococcus lactis to surface express pneumococcal vaccine antigens, with the scientific objective of developing a live vaccine protective against pneumococcal infection. • Gram-positive expression vectors were constructed for heterologous expression of streptococcal surface proteins. • Developed animal models of immunization and bacterial challenge to assess immune response generated following vaccination and level of protection. • ELISA determined antibody titer and isotypes were, while T-cell proliferation assays were developed to assess the presence of an antigen-specific T-cell response following vaccination. Show less As an industrial scientist within the vaccine development division of Provalis Plc, I was tasked with engineering strains of Lactococcus lactis to surface express pneumococcal vaccine antigens, with the scientific objective of developing a live vaccine protective against pneumococcal infection. • Gram-positive expression vectors were constructed for heterologous expression of streptococcal surface proteins. • Developed animal models of immunization and bacterial challenge to assess… Show more As an industrial scientist within the vaccine development division of Provalis Plc, I was tasked with engineering strains of Lactococcus lactis to surface express pneumococcal vaccine antigens, with the scientific objective of developing a live vaccine protective against pneumococcal infection. • Gram-positive expression vectors were constructed for heterologous expression of streptococcal surface proteins. • Developed animal models of immunization and bacterial challenge to assess immune response generated following vaccination and level of protection. • ELISA determined antibody titer and isotypes were, while T-cell proliferation assays were developed to assess the presence of an antigen-specific T-cell response following vaccination. Show less