Date of Award
M.S. in Pharmaceutical Science
Pharmaceutics and Drug Delivery
Mark T. Hamann
Stephen J. Cutler
Endophytes are bacterial and fungal microbes that live inside of plant tissue without causing disease. Endophytes have applications in many industries including the pharmaceutical and food industries as producers of natural products. This potential was demonstrated by investigating the natural product production from a Bacillus amyloliquefaciens endophyte of Platanus occidentalis using a combination of MALDI-IMS, LC-MS, MS-MS, and NMR methods, by purifying nicotianamine from soy flour, and by reviewing natural product inhibitors of the hepatitis C virus (HCV). The secondary metabolite production of the endophytic B. amyloliquefaciens was investigated under a variety of fermentation conditions. It was discovered that the endophyte produces rapamycin, a molecule previously reported only from Streptomyces hygroscopicus from Easter Island in the South Pacific. Other known natural products from the Bacillus genus were identified using LC-MS including the lipopeptide fengycins, surfactins, and iturins. Iturin A3 was isolated and characterized from the endophyte, and found in the host P. occidentalis, as shown by LC-MS. The presence of a possible rapamycin analogue was discovered which would be indicative of a biotransformation process. Challenge experiments were conducted using MALDI-IMS in an attempt to understand host regulation of secondary metabolites. Iturin production increased as shown by MALDI-IMS. The impetus for studying endophytes like B. amyloliquefaciens for natural products was further exemplified by purifying a natural metal chelator, nicotianamine, from soy flour. This is a possible candidate to replace ethylenediaminetetraacetic acid (EDTA), a synthetic metal chelator used to prevent food spoilage. Further studies on possible endophytic production of nicotianamine could be of great importance to many food companies. The importance of studying endophytes was further shown by reviewing the number of novel and known natural products that have been reported with activity against the hepatitis C virus (HCV). There are numerous examples in the literature of metabolites being reported as plant-derived which are later identified as ultimately being produced by endophytic organisms. This review demonstrates the importance of studying new and known sources of HCV active metabolites for endophytic organisms.
James, Michael C., "Secondary Metabolite Production By An Endophytic Bacillus sp. from Platanus Occidentalis" (2014). Electronic Theses and Dissertations. 1344.