Wednesday, 18 April 2018

Formation of bacterial spores

Bacterial spores store information about the individual growth history of their progenitor cells, thus retaining a "memory" that links the different stages of the bacterial life cycle. This phenomenon was demonstrated in a recent study.

The researchers studied the adaptive bacterial life cycle using Bacillus subtilis as a model organism. Through the use of time-lapse microscopy, they were able for the first time in this context to observe and to study sporulation and spore revival at the single-cell level -- and how they correlate. They discovered that the spores responded very differently to the influx of new nutrients: The spores that formed earlier during a nutrient down-shift revived more quickly.

The metabolic enzyme alanine dehydrogenase contributes to this effect, according to the researchers. Bacteria produce the enzyme when the amino acid L-alanine is available and stop synthesis once it runs out. Dr Bischofs explains that the enzyme is passed down from one generation of bacteria to the next by carry-over until spores are formed. The enzyme is then stored in the new spores, where it remains inactive until new nutrients arrive that facilitate spore revival and re-growth.


Alper Mutlu, Stephanie Trauth, Marika Ziesack, Katja Nagler, Jan-Philip Bergeest, Karl Rohr, Nils Becker, Thomas Höfer, Ilka B. Bischofs. Phenotypic memory in Bacillus subtilis links dormancy entry and exit by a spore quantity-quality tradeoff. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02477-1

Posted by Dr. Tim Sandle

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