Electrophoretic Patterns of Proteins in the Genus Bifidobacterium and Proposal of Four New Species

Abstract

The polyacrylamide gel electrophoretic patterns of soluble cellular proteins from 1,094 strains of bifidobacteria were compared with available deoxyribonucleic acid (DNA)-DNA homology data and with the phenotypic and biochemical reactions of these strains. There was excellent correlation between the 25 distinct protein patterns and 24 DNA-DNA homology groups in the genus. Differentiation among species on the basis of common phenotypic properties often was unreliable. Our results demonstrate that the species previously known as "Bifidobacterium eriksonii" is a synonym of Bifidobacterirrm dentium Scardovi and Crociani; that "Actinomyces parabijdus" is a synonym of Among the 20 species of the genus Bifidobacterium cited on the Approved Lists of Bacterial Names ( 3 3 ) , several genetically distinct species from humans and other animals cannot be differentiated reliably by commonly used enzymatic or fermentation reactions (5) or by zymograms of transaldolases and 6-phosphogluconate dehydrogenases (23). Several authors have reported the use of polyacrylamide gel electrophoresis (PAGE) of soluble cellular proteins to distinguish species or serovars (serotypes) of bacteria (1, 4, 8, 9, 11, 32, 35) or to determine the similarity of unidentified isolates (15). The present study was designed to determine the reliability and sensitivity of a PAGE procedure (15) to distinguish genetically related and unrelated species of bifidobacteria. For this purpose we compared the electrophoretograms of BiJidobacterium type strains and many other strains that were previously identified according to their deoxyribonucleic acid (DNA)-DNA homology characteristics or phenotypic characteristics or both. MATERIALS AND METHODSBacterial strains. The strains examined are listed in Table 1.Methods. The biochemical properties of the strains were determined by methods previously described by Holdeman et al. ( 5 ) . The DNA-DNA homology values used were from previously published data (10. 23, 24, 26, 27, 29-31, 37, 38) and were obtained by the methods described by Scardovi et al. (24. 29).For electrophoretic analyses, cells were inoculated into 5 ml of supplemented brain heart infusion broth ( 5 ) containing 0.1% calcium carbonate and 0.025% (final concentration) Tween 80 and then incubated at 37°C for 24 h. Growth was harve3ted by centrifugation at 8,000 X g for 10 min. Electrophoretic analysis of cellular soluble proteins was performed by using the procedures of Moore et al. (15). The similarity of patterns on different gels was determined by placing cut photographs adjacent to each other. Strains with similar protein patterns were reanalyzed on single gels for direct visual comparisons. RESULTS AND DISCUSSIONThe DNA-DNA homology relationships among species of the genus Bifdobacterium have been studied extensively. Many of the species show close genetic relationships, and several species have similar phenotypic characteristics. Therefore, the species in this genus provide an ideal test of the sensitivity and reliability of the application of PAG...

Characterization of a Novel β-l-Arabinofuranosidase in Bifidobacterium longum

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Polyacrylamide Gel Electrophoresis of Whole-Cell Preparations of Actinomyces spp.

“…(7, 8 , 13). Taxonomic groupings based on PAGE of proteins closely resemble groupings based on DNA-DNA homology data (1,15).…”

“…PAGE of soluble proteins can be used to differentiate closely related bacteria (1,11,13,17) and has been used to show differences among strains of Actinomyces spp. (7, 8 , 13).…”

Functional Analysis of Degradative Enzymes for Hydroxyproline-linked ^|^beta;-L-Arabinofuranosides in Bifidobacterium longum

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