Biomedical Engineering Reference
In-Depth Information
when co-cultured with
L. plantarum
DC400 or
L. brevis
CR13. The co-cultivation
with
L. rossiae
A7 did not interfere with survival compared to the mono-culture.
The analysis of the proteome revealed the induction of several cytoplasm proteins
of
L. sanfranciscensis
CB1, especially when associated with
L. plantarum
DC400.
The majority of the induced proteins had a key role in the mechanisms of response
to environmental stresses, leading to the hypothesis that co-cultivation with some
species of lactic acid bacteria could be considered like an environmental stress
which promoted cell communication. A central role for the LuxS protein was estab-
lished, while also furanone derivatives were identified as presumptive signaling
molecules. The synthesis of volatile compounds and the activity of peptidases also
decreased when
L. sanfranciscensis
CB1 was cultivated together with
L. plantarum
DC400. The mechanisms of cell communication were also studied in
L. plantarum
DC400 [
166
]. The co-cultivation of this strain with other sourdough lactic acid bac-
teria did not interfere with survival compared to the mono-culture. Nevertheless, the
analysis of the proteome revealed the induction of proteins involved in the response
to environmental stresses and cell communication.
Lactobacillus plantarum
DC400
synthesized the pheromone plantaricin A (PlnA) at variable concentrations that
depended on the associated microbial species [
167
] . The co-cultivation with
L. pen-
tosus
,
L. brevis
and other sourdough lactic acid bacteria species did not modify the
synthesis of PlnA compared to the mono-culture conditions and did not show effects
on the viability and survival of the other species. On the contrary, the co-cultivation
with
L. sanfranciscensis
increased the synthesis of PlnA and caused a decrease of
the viability of this species. The same effect was found during growth of
L. sanfran-
ciscensis
in the presence of the chemically synthesized PlnA. Under these environ-
mental conditions, the analysis of the proteome revealed the over-expression of
proteins that had a central role in the energy metabolism, catabolism and biosynthesis
of proteins and amino acids, stress responses, homeostasis of the redox potential, and
programmed cell death. Notwithstanding antimicrobial activities due to substrate
competition and synthesis of inhibitory compounds (e.g., phenyl lactic acid), and the
elevated capacity to adapt to changing environments, it could be hypothesized that
the dominance of
L. plantarum
during sourdough fermentation [
168
] may relate to
the synthesis of the pheromone/bacteriocin PlnA as stimulated by mechanisms of
quorum sensing.
References
1. Gobbetti M, De Angelis M, Corsetti A, Di Cagno R (2005) Biochemistry and physiology of
sourdough lactic acid bacteria. Trends Food Sci Technol 16:57-69
2. Gobbetti M (1998) The sourdough microflora: interactions of lactic acid bacteria and yeast.
Trends Food Sci Technol 9:267-274
3. Gänzle MG, Vermeulen N, Vogel RF (2007) Carbohydrate, peptide and lipid metabolism of
lactic acid bacteria in sourdough. Food Microbiol 24:128-138
4. Hammes WP, Gänzle MG, Hammes WP, Gänzle MG (1998) Sourdough bread and related
products. In: Wood BJB (ed) Microbiology of fermented foods, vol 199. Blackie Academic
and Professional, London
