Bifid Shape Is Intrinsic to Bifidobacterium adolescentis.

Although the genus Bifidobacterium was originally named for its bifid morphology, not all
bifidobacterial species have a similar structure, and very few of them adopt a bifid shape
under stress conditions. The exposure of respective bifidobacterial species to various
conditions, such as different pH, temperatures, medium components, in vivo growth
in Caenorhabditis elegans, and subculture, did not affect their diverse morphologies.
Extensive scanning electron microscopy studies suggested that the bifid shape of
B. adolescentis are maintained irrespective of the conditions. Hence, we conclude
that the bifid morphology is intrinsic to B. adolescentis. Most bifidobacterial species
are anaerobic and rod-shaped, whereas, after the first generation, they become
microaerophilic or aerophilic. CaCl2 (treatment of B. animalis) signaling triggered a
change from the rod shape to the bifid shape and vice versa in B. adolescentis.