K Iijima1, K Suzuki, K Ozaki, H Yamashita. 1. Analytical Technology Laboratory, Asahi Breweries, Ltd, Ibaraki, Japan. kazumaru.iijima@asahibeer.co.jp
Abstract
AIMS: To determine whether horC confers beer-spoilage ability and to evaluate the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of lactic acid bacteria (LAB). METHODS AND RESULTS: Hop-sensitive Lactobacillus brevis ABBC45cc was transformed with an expression plasmid, pHYchorBC, containing putative multidrug resistance gene horC and its putative regulator horB, and the transformant was designated as ABBC45cc/pHYchorBC. As a control, ABBC45cc was transformed with pHYchorB that contains horB, and the transformed strain was designated as ABBC45cc/pHYchorB. As a result of beer-spoilage assay of these transformants, ABBC45cc/pHYchorBC exhibited beer-spoilage ability, whereas ABBC45cc/pHYchorB did not. Furthermore ABBC45cc/pHYchorBC showed higher hop resistance than ABBC45cc/pHYchorB, accounting for the differences in beer-spoilage ability observed between the two transformants. ABBC45cc/pHYchorBC also exhibited higher resistance to various structurally unrelated drugs, compared with ABBC45cc/pHYchorB. CONCLUSIONS: horC was shown to confer hop resistance and beer-spoilage ability on ABBC45cc by presumably encoding a multidrug transporter. SIGNIFICANCE AND IMPACT OF THE STUDY: The finding that horC plays an important role in hop resistance and beer-spoilage ability supports the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of LAB.
AIMS: To determine whether horC confers beer-spoilage ability and to evaluate the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of lactic acid bacteria (LAB). METHODS AND RESULTS: Hop-sensitive Lactobacillus brevisABBC45cc was transformed with an expression plasmid, pHYchorBC, containing putative multidrug resistance gene horC and its putative regulator horB, and the transformant was designated as ABBC45cc/pHYchorBC. As a control, ABBC45cc was transformed with pHYchorB that contains horB, and the transformed strain was designated as ABBC45cc/pHYchorB. As a result of beer-spoilage assay of these transformants, ABBC45cc/pHYchorBC exhibited beer-spoilage ability, whereas ABBC45cc/pHYchorB did not. Furthermore ABBC45cc/pHYchorBC showed higher hop resistance than ABBC45cc/pHYchorB, accounting for the differences in beer-spoilage ability observed between the two transformants. ABBC45cc/pHYchorBC also exhibited higher resistance to various structurally unrelated drugs, compared with ABBC45cc/pHYchorB. CONCLUSIONS: horC was shown to confer hop resistance and beer-spoilage ability on ABBC45cc by presumably encoding a multidrug transporter. SIGNIFICANCE AND IMPACT OF THE STUDY: The finding that horC plays an important role in hop resistance and beer-spoilage ability supports the validity of horC as a trans-species genetic marker for differentiating the beer-spoilage ability of LAB.