Development of a 16s rRNA targeted probe to identify and characterize Lactobacillus population



Lawson, Melissa A.E.

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University of Guelph


Lactobacilli are important members of the microbiota in swine. These bacteria have the ability to inhibit growth of pathogens and modulate the microenvironment of the gastrointestinal tract. The thesis objectives were to design a 16S rRNA 'Lactobacillus'-specific oligonucleotide probe that could be converted into a peptide-nucleic-acid (PNA) probe, and then to evaluate this probe using 'Lactobacillus' spp. and ' in vivo.' Examination by microbial fluorescence 'in situ' hybridization demonstrated that G'Lac'385 has superior specificity, sensitivity and efficiency in detection of 'Lactobacillus' organisms. G'Lac'385 was also examined 'in vivo,' and this research suggests that feces should not be used as a reliable indicator for 'Lactobacillus' populations present in swine ileum. Also, these results indicate that population changes in 'Lactobacillus ' are host-dependant. The ability of G'Lac'385 to rapidly detect, identify and enumerate 'Lactobacillus' populations in mixed samples is a valuable tool that can be used for quantification of Lactobacilli in future research.



lactobacilli, indentification, 16S rRNA, Lactobacillus-specific oligonucleotide probe, peptide-nucleic-acid probe