Differentiation of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus delbrueckii subsp. lactis by SDS-PAGE of cell-wall proteins.
OBJECTIVE
In the present study, a method based on SDS-PAGE fingerprinting of surface layer proteins was developed to identify Lactobacillus delbrueckii subsp. bulgaricus and subsp. lactis dairy isolates.


RESULTS
The two subspecies, identified by species-specific PCR, were characterized by different SDS-PAGE cell-wall protein profiles; subspecies bulgaricus showed one band of about 31 kDa which, in some cases, was observed at a doublet, and subspecies lactis showed one band of about 21 kDa or 18 kDa.


CONCLUSIONS
The sensitivity of this procedure for discriminating between the two subspecies was very high. The different types of SDS-PAGE profile for cell-wall proteins of the strains studied in this work did not seem to be correlated to the different dairies of origin.


CONCLUSIONS
The method appears to be an efficient taxonomic tool. It has the advantage of easy gel interpretation over fingerprinting of whole-cell protein extracts, and may be used as an alternative to established PCR-based techniques which, though rapid and safe, require expensive instruments and reagents.
Gatti
M
M
Istituto Sperimentale Lattiero Caseario, Lodi, Italy.
Fornasari
M E
ME
Neviani
E
E
D001426:Bacterial Proteins / Q000032:analysis*; D002473:Cell Wall / Q000737:chemistry; D002965:Classification; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D007778:Lactobacillus / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D013045:Species Specificity
D001426:Bacterial Proteins