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Effect of growth at low pH on the cell surface properties of a typical strain of Lactobacillus casei group


Hossein Nezhad, M and Stenzel, DJ and Britz, ML, Effect of growth at low pH on the cell surface properties of a typical strain of Lactobacillus casei group, Iranian Journal of Microbiology, 2, (3) pp. 144-151. ISSN 2008-3289 (2010) [Refereed Article]

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Copyright 2010 Tehran University of Medical Sciences

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Background and Objectives: Although members of the Lactobacillus casei group are known to survive under acidic conditions, the underlying mechanisms of growth at acidic condition and the impact of low pH on the relative level of protein expression at the cell surface remain poorly studied. Material and Methods: After confirming the taxonomy of L. casei strain GCRL 12 which was originally isolated from cheese and confirmed by 16S rRNA sequence analysis, the impact of acidic pH on growth rate was determined. Results: Late log-phase cells cultured at pH 4.0 showed obvious changes in Gram staining properties while transmission electron microscopy analysis revealed evidence of structural distortions of the cell surface relative to the controls cultured at pH 6.5. When comparing cytosolic or whole cell preparations on SDS-PAGE, few changes in protein profiles were observed under the two growth conditions. However, analysis of surface protein extracted by 5M LiCl demonstrated changes in the proportions of proteins present in the molecular weight range of 10 to 80 kDa, with some proteins more dominant at pH 6.5 and other at pH 4. Conclusion: These data suggest that surface proteins of this strain are associated with growth and survival at low pH. The function of these proteins is subject to further investigation.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Food sciences
Research Field:Food sciences not elsewhere classified
Objective Division:Manufacturing
Objective Group:Industrial chemicals and related products
Objective Field:Industrial chemicals and related products not elsewhere classified
UTAS Author:Britz, ML (Professor Margaret Britz)
ID Code:70209
Year Published:2010
Deposited By:Agricultural Science
Deposited On:2011-06-07
Last Modified:2011-09-26

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