title: DGGE and real-time PCR analysis of lactic acid bacteria in bacterial communities of the phyllosphere of lettuce.
abstract: Food associated indigenous microbial communities exert antagonistic effects on pathogens and may routinely deliver health relevant microorganisms to the GI tract. By using molecular, culture independent methods including PCR-DGGE of 16S rDNA-coding regions and real-time PCR (RT-PCR) as well as BIOLOG metabolic fingerprinting, microbial communities on lettuce were analyzed in samples from fields, from supermarkets and soil. Amplified 16S rRNA gene sequences (57.7%) could be assigned to species previously reported as typical for the phyllosphere including Pantoea agglomerans, Pseudomonas flavescens, Moraxella spp., and Mycobacterium spp. 71.8% of the sequences obtained represented so far undescribed taxa. Principal component analysis of BIOLOG metabolic profiles indicated a seasonal variation in the lettuce phyllosphere microbial community structure. Various lactic acid bacteria were detected including several Lactobacillus and Leuconostoc species in particular on lettuce from organic farming. By RT-PCR lactobacilli were found with a range of abundances from 1x10(4 )to 1x10(5 )copies/g lettuce. Considering the importance of salad in many diets lettuce may contribute to a constant supply with LAB.
authors.affiliation: Department of Nutritional Sciences, University of Vienna, Austria.
authors.forename: Jutta
authors.initials: J
authors.lastname: Zwielehner
authors.forename: Michael
authors.initials: M
authors.lastname: Handschur
authors.forename: Astrid
authors.initials: A
authors.lastname: Michaelsen
authors.forename: Selen
authors.initials: S
authors.lastname: Irez
authors.forename: Michael
authors.initials: M
authors.lastname: Demel
authors.forename: Ewald B M
authors.initials: EB
authors.lastname: Denner
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Haslberger
mesh_terms: D001406:Bacillaceae / Q000235:genetics / Q000302:isolation & purification; D016172:DNA Fingerprinting / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D007778:Lactobacillus / Q000235:genetics* / Q000302:isolation & purification; D018545:Lactuca / Q000382:microbiology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S