65C-8

I. SURJAWAN, C. L. Hicks, and N. S. Jose. Food Science, University of Kentucky, 216D W. P. Garrigus Bldg, Lexington, KY 40546-0215

Attachment proteins from different bacteriophage may bind to similar carbohydrates on the host surface.

Therefore, the objective of this study was to investigate whether c2 bacteriophage-peptides could inhibit the proliferation of Lactobacillus plantarum bacteriophage (yit0068) in host L. plantarum.

Peptides were prepared by hydrolyzing Lactococcus lactis ssp. lactis c2 phage (1 x 10⁸ pfu/mL) with ficin (0.01%) for 6 hr at 31^oC. Hydrolyzed phage was microfiltered (MiniKross) through a hollow-fiber membrane (0.2 mm) to remove cellular debris. Filtrate was ultrafiltered through a YM3 (Millipore) UF membrane (3,000 MW cut-off) at 5^oC and freeze dried. The c2 peptide was tested for its effect on phage proliferation by monitoring the growth (l_600nm) of L. plantarum (4%) in MRS medium with CaCl₂ containing 2 and 5% peptide at 35^oC. One hr after L. plantarum was added to the growth media (0.01%, the medium was infected with L. plantarum yit0068 phage (1 x 10⁸ pfu/mL). Controls were prepared in the same media with and without peptide and phage present.

Results showed that c2 phage-peptides inhibited onset of phage lysis by up to 60 min, compared to lysis of the control (no phage peptide added). No difference in lyse times were observed between media that contained 2% and 5% peptide concentrations. Lysis slopes of the cells grown in the peptide media were the same as the control (average slope=-0.04 A/min ± 0.003). When L. plantarum in MRS medium containing 2% c2 peptide was infected with 10², 10⁴, or 10⁶ yit0068 phage/mL after 1 hr of incubation, lysis only occurred in the medium that was infected with 106 phage.

These results suggest that c2 phage peptide is a potent inhibitor of L. plantarum yit0068 phage proliferation and may have activity across multiple cultures.