INVESTIGADORES
ARGAÑARAZ MARTINEZ Fernando Eloy
artículos
Título:
Fluorescence in situ hybridization for detection of classical propionibacteria with specific 16S rRNA-targeted probes and its application to bacteria enumeration in a Gruyère cheese
Autor/es:
JAIME D. BABOT; MAXIMILIANO HIDALGO; ELOY ARGAÑARAZ MARTÍNEZ; MARÍA C. APELLA; ADRIANA PEREZ CHAIA
Revista:
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2011 vol. 145 p. 221 - 228
ISSN:
0168-1605
Resumen:
The classical or dairy propionibacteria have well-documented industrial applications and have been proposed
for probiotic applications. Given their industrial importance it is necessary to employ fast and reliable
techniques to monitor the growth during products elaboration, industrial fermentations or the intestinal
transit. Therefore, the aim of this investigation was to design oligonucleotide probes targeting the 16S rRNA of
dairy propionibacteria and optimise the fluorescence in situ hybridization (FISH) protocol to detect these
bacteria. Two specific probes were in silico designed to detect Propionibacterium freudenreichii and P. jensenii,
named Pfr435 and Pj446 respectively. The FISH protocol was optimised for the hybridisation of
propionibacteria cells with the universal probe Eub338 and the designed probes. These probes were assayed
in situ for their specificity to hybridise species of propionibacteria by observation using fluorescence
microscopy and results were compared with the probe Pap446 previously designed for P. acidipropionici.
Probes Pap446, Pfr435 and Pj446 were also evaluated by fluorescence spectrophotometry to assess the
influence of cells physiological state during growth in batch culture in the fluorescence intensity. The
maximum fluorescence intensity was observed at the onset of the stationary phase of growth and was then
reduced. However, changes on the cells permeability did not reduce the efficiency of 16S rRNA hybridisation
with the fluorescence-labelled probes. Propionibacteria counts obtained by FISH and plate count methods
were compared in a commercial Gruyère cheese. The results showed that this method can be used as a rapid
technique for the enumeration of these bacteria in cheese samples