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Closing the In Vitro/In Vivo Gap in Tuberculosis Drug Discovery

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posted on 20.06.2014 by Geping Cai
This study establishes a new anti-M. tuberculosis (M. tb) drug lead screening scheme that integrates in vitro and in vivo methods for early detection of bioactive constituents during the purification of nature-derived extracts. Two in vivo M. tb quantification methods were established: 1) the determination of a Mycobacterium genus-specific cell wall fatty acid, tuberculostearic acid, with GC-MS/MS and 2) determination of M. tb marker RNAs with real-time PCR. Both are efficient, accurate and relatively inexpensive, and adaptable to in vitro and in vivo M. tb growth and inhibition monitoring in anti-M. tb drug discovery programs. The conventional in vitro high-throughput phenotypic screening, the newly designed M. tb bioautography on thin layer chromatography plates, as well as the determination of quantitative purity-activity relationship study all aid in exploring and screening for bioactive principles in a crude state. Two classes of cyclic peptides, hytramycins and a xylamycin, were isolated from the extracts of two different actinomycete strains through bioassay-guided fractionation. The structures were elucidated mainly with LC-MS and 1D/2D-NMR. Both peptides contain unusual amino acid residues in the structural cores, and also exhibit strong anti-M. tb activity in vitro with unique antimicrobial mechanisms of action.

History

Advisor

Franzblau, Scott G.Pauli, Guido F.

Department

Medicinal Chemistry and Pharmacognosy

Degree Grantor

University of Illinois at Chicago

Degree Level

Doctoral

Committee Member

Franzblau, Scott G. Jaki, Birgit U. Cho, Sanghyun Seigler, David S.

Submitted date

2014-05

Language

en

Issue date

20/06/2014

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