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ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2009 Conference Abstract
| Type of Submission |
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Submission Type: |
Poster |
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Subject Category: |
Applied and Environmental Microbiology |
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| Session Information |
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Presentation Date: |
Wednesday June 17 |
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Abstract ID: |
AE55 |
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Session: |
Poster Session II |
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Time: |
15:00 |
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| Presenting Author |
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| Other Authors |
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M HAAKENSEN, University of Saskatchewan
B CHABAN, University of Saskatchewan
B ZIOLA, University of Saskatchewan
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| Title |
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Save the beer! Rapid detection and identification of beer-spoiling Pectinatus organisms |
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| Abstract Text |
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The environment found in beer is very harsh, containing antimicrobial hop compounds and ethanol, as well as having a low nutrient status. Consequently, most bacteria are unable to survive in beer. However, some bacteria have developed mechanisms that allow them to grow in beer, thus becoming spoilage organisms. Currently, the most common beer-spoiling bacteria are classified into two groups, either gram-positive facultative anaerobes or gram-negative anaerobes. The most frequent gram-negative anaerobic beer-spoilers belong to the genus Pectinatus. This genus consists of three species, Pectinatus cerevisiiphilus, P. frisingensis and P. haikarae, all of which can spoil beer, with P. cerevisiiphilus being the most problematical of the three. Current detection systems for Pectinatus can be time consuming, first requiring growth and then identification of the contaminating bacteria. As such, an easier and faster detection and identification system would enable quality control measures to be quickly put in place, thus avoiding major economic loss. A surface-accessible major outer membrane protein (MOMP) from P. cerevisiiphilus had previously been isolated and N-terminal sequenced. Using conventional- and Bubble-PCR (genome walking) methods, the entire MOMP gene sequence was obtained from two P. cerevisiiphilus isolates, three P. frisingensis isolates, and one P. haikarae isolate. These MOMP genes were found to have several variability regions, particularly in the C-terminal portion of the protein. Multiple sequence alignments of these MOMP genes provided regions unique to each isolate, as well as species-specific regions. This study reports on progress in developing a detection and identification system for Pectinatus organisms using this MOMP gene as a target. A PCR-based identification system has been assembled, enabling differentiation among species via PCR product band sizes. Further, identification of individual isolates is possible by sequence analysis of the product bands, with each isolate having variable regions that enable their identification. This information is extremely useful for a brewery, as it identifies if an isolate is a reoccurring or newly introduced contamination. As well, knowing which Pectinatus species is present in beer will provide information regarding the severity of the problem, as P. cerevisiiphilus is able to spoil beer quicker than the other two species. Efforts are currently underway to develop a real-time PCR system that would enable identification of isolates without sequencing product bands. |
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