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Poster: Biology & Disease Mgmt: Biological Control


Seasonal variation in the antibacterial activity of latex-like resin from Sciadopitys verticillata
K. GWINN (1), D. Yates (1), B. Ownley (1), N. Labbe' (1) (1) University of Tennessee, U.S.A.

Japanese umbrella pine, Sciadopitys verticillata, produces a latex-like resin with antibacterial activity. To determine seasonal antibacterial activity, resin was collected in summer and winter of 2015, stored at -20°C, autoclaved twice, and suspended in sterile deionized water. Resin was tested within two months of collection. Bacterial suspensions (100 µl) from nutrient broth (NB) overnight cultures were mixed with NB (100 µl), treated with resin suspension, and incubated overnight at 26°C with shaking. Treatments were: 0 (control), 25, 50, and 100 µl resin suspension diluted in water (total volume 100 µl). Colony-forming units were determined with dilution plating. Separate tests were conducted with winter and summer-collected resins, and bacterial species were evaluated individually. Data (number of treatment colonies relative to control colonies) were analyzed with mixed models ANOVA. Differences were significant at P=0.05. Exposure to resin collected in winter reduced numbers of colonies of Bacillus cereus, Erwinia amylovora, Agrobacterium tumefaciens, and Escherichia coli, and increased numbers of Xanthomonas campestris, Pseudomonas fluorescens (Pf), and Pseudomonas syringae. Exposure to resin collected in summer affected population growth of two bacterial species; colony counts of E. amylovora decreased and those of P. fluorescens increased. Future research will address the role of chemical composition and resin concentration on antibacterial activity.