Date of Award

8-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Microbiology

Advisor

Tzeng, Jeremy T-R

Committee Member

Barefoot , Susan

Committee Member

Gangemi , Joseph

Abstract

Jenseniin P, a bacteriocin discovered by Prince, can inhibit the growth of several strains of propionibacteria and lactobacillus(Prince 1993). Ratnam further purified jenseniin P by ammonia sulfate precipitation and anion exchange chromatography. In that study, partially purified jenseniin P was stable in various pH ranges, SDS concentrations, several solvents, and remained active after holding at 100 ¡C for 60 minutes. The molecular weight was estimated to be between 6 and 9 kDa. In addition, jenseniin P was demonstrated to be inhibitory to Propionibacterium acnes using the spot-on-lawn method. Thus, Ratnam postulated its possible application in acne treatment(Ratnam 1997).
In this present work, jenseniin P was further purified using C18 resin silica column. Vivaspin and ammonia sulfate precipitation methods were also evaluated. This further purified jenseniin P was inactivated by trypsin, pronase, and protease K, which confirmed its proteinaceous nature. The molecular weight of jenseniin P was further narrowed down to be between 4.5 and 5kDa. Jenseniin P was characterized to be pH stable and heat stable using a microtiter plate method developed in this work, which was 8-fold more sensitive than the previous critical dilution method described by Ratnam. The mode of action of jenseniin P was determined to be bactericidal with a killing rate of 2.38 log h-1.
We also detected a new agent produced by Propionibacterium jensenii B1264 that inhibited the growth of Propionibacterium acnes 6919 but not Lactobacillus delbrueckii subsp. lactis ATCC 4797, the indicator strain used in previous studies. This inhibitory agent was recovered from the 30% acetonitrile elution fraction of C18 resin silica column purification process, which was different from the previously reported jenseniin P, because the jenseniin P that inhibited the growth of L. delbrueckii subsp. lactis ATCC 4797 was mostly recovered from the 50% acetonitrile elution fraction. This P. acnes specific inhibitory agent is currently being investigated.

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Microbiology Commons

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