Other Publications (1)
Articles by Kathryn E. Capasso in JoVE
Purification and microRNA Profiling of Exosomes Derived from Blood and Culture Media Marguerite K. McDonald1, Kathryn E. Capasso1, Seena K. Ajit1 1Department of Pharmacology & Physiology, Drexel University College of Medicine The presence of stable microRNAs (miRNAs) in exosomes has generated immense interest as a novel mode of intercellular communication, for their potential utility as biomarkers and as a route for therapeutic intervention. Here we demonstrate exosome purification from blood and culture media followed by quantitative PCR to identify miRNAs being transported.
Other articles by Kathryn E. Capasso on PubMed
The Characterization of a Unique Trypanosoma Brucei Î²-hydroxybutyrate Dehydrogenase Molecular and Biochemical Parasitology. Oct, 2011 | Pubmed ID: 21767577 A putative Î²-hydroxybutyrate dehydrogenase (Î²HBDH) ortholog was identified in Trypanosoma brucei, the unicellular eukaryotic parasite responsible for causing African Sleeping Sickness. The trypanosome enzyme has greater sequence similarity to bacterial sources of soluble Î²HBDH than to membrane-bound Type I Î²HBDH found in higher eukaryotes. The Î²HBDH gene was cloned from T. brucei genomic DNA and active, recombinant His-tagged enzyme (His(10)-TbÎ²HBDH) was purified to approximate homogeneity from E. coli. Î²HBDH catalyzes the reversible NADH-dependent conversion of acetoacetate to D-3-hydroxybutyrate. In the direction of D-3-hydroxybutyrate formation, His(10)-TbÎ²HBDH has a k(cat) value of 0.19 s(-1) and a K(M) value of 0.69 mM for acetoacetate. In the direction of acetoacetate formation, His(10)-TbÎ²HBDH has a k(cat) value of 11.2 s(-1) and a K(M) value of 0.65 mM for D-3-hydroxybutyrate. Cofactor preference was examined and His(10)-TbÎ²HBDH utilizes both NAD(H) and NADP(H) almost equivalently, distinguishing the parasite enzyme from other characterized Î²HBDHs. Furthermore, His(10)-TbÎ²HBDH binds NAD(P)(+) in a cooperative fashion, another unique characteristic of trypanosome Î²HBDH. The apparent native molecular weight of recombinant His(10)-TbÎ²HBDH is 112 kDa, corresponding to tetramer, as determined through size exclusion chromatography. RNA interference studies in procyclic trypanosomes were carried out to evaluate the importance of TbÎ²HBDH in vivo. Upon knockdown of TbÎ²HBDH, a small reduction in parasite growth was observed suggesting Î²HBDH has an important physiological role in T. brucei.