Translations:Lactobacillus acidophilus/5/en

Biological and biochemical features

Morphology

Lactobacillus acidophilus image taken with a scanning electron microscope (SEM).

A Lactobacillus acidophilus culture

Lactobacillus acidophilus is an immobile rod-shaped (bacillus), gram-positive organism that ranges in size from 2-10 μm in size. L. acidophilus has one phospholipid bilayer membrane with a large cell wall consisting of peptidoglycan exterior to the membrane. The cell wall of L. acidophilus is interwoven with teichoic acids and surface proteins, with anionic and neutral polysaccharides as well as an S-layer lining the exterior of the cell. The S-layer proteins of L. acidophilus have been shown to adhere to epithelial cells as well as mucus and other extracellular proteins. The S-layer is made of two structural domains. The C-terminal domain is responsible for cell wall anchoring, while the N-terminal domain is responsible for interacting with the cell environment, as well as S-layer self assembly. In the L. acidophilus species, the N-terminal region shows high amino acid variability along with low sequence homology (31-72%). However, the C-terminus shows low amino acid variability and high amino acid sequence homology (77-99%).L. acidophilus does not have any extracellular means of motion like a flagellum or pilli, and therefore is an immobile microbe.

Lactobacillus acidophilus under microscope with dark light background.