The emergence of antibiotic resistant bacteria is threatening the efficacy of antibiotics. However, antibiotic discovery rate had declined in the past few decades. To study the factors that affect the yield of antibiotics, 4 strains of Streptomyces tenebrarius were studied: A09 ΔaprX14, A09, ZR and A09 ΔaprX15 which produced different levels of apramycin, a promising aminoglycoside antibiotic. Relative to A09, ΔaprX14, ZR and ΔaprX15 produced 152%, 38% and 4% of apramycin. The S. tenebrarius proteome was observed under different growth conditions: the seed liquid and the fermentation culture. Two sample preparation methods, acetone precipitation and filter-aided sample preparation, were performed and compared. In total, 4,159 unique proteins were identified in samples prepared by...[ Read more ]

The emergence of antibiotic resistant bacteria is threatening the efficacy of antibiotics. However, antibiotic discovery rate had declined in the past few decades. To study the factors that affect the yield of antibiotics, 4 strains of Streptomyces tenebrarius were studied: A09 ΔaprX14, A09, ZR and A09 ΔaprX15 which produced different levels of apramycin, a promising aminoglycoside antibiotic. Relative to A09, ΔaprX14, ZR and ΔaprX15 produced 152%, 38% and 4% of apramycin. The S. tenebrarius proteome was observed under different growth conditions: the seed liquid and the fermentation culture. Two sample preparation methods, acetone precipitation and filter-aided sample preparation, were performed and compared. In total, 4,159 unique proteins were identified in samples prepared by acetone precipitation and 1,983 unique proteins were identified in samples prepared by filter-aided sample preparation. Several kinases were found to be differentially expressed in fermentation mycelia from the seed liquid. Multiple acyl transferase proteins were downregulated in ΔaprX15 fermentation mycelia. Most of the proteins related to apramycin biosynthesis were found to be downregulated, except for the putative aminoglycoside phosphatase AprZ. The role of this protein has yet to be elucidated but could play an important role in determining the yield of apramycin. This thesis laid the foundation for the proteomic analysis of S. tenebrarius. The filter-aided sample preparation method proved to be a more robust method for the proteomics analysis of S. tenebrarius due to metabolite interference in the acetone precipitation sample preparation.