Environmental stress responses in Lactococcus lactis

Environmental stress responses in Lactococcus lactis

Bacteria can encounter a variety of physical conditions during their life. Bacterial cells are able to survive these (often adverse) conditions by the induction of specific or general protection mechanisms. The lactic acid bacterium Lactococcus lactis is widely used for the production of cheese. Before and during this process as well as in its natural habitats, it is subjected to several stress...

Glutathione protects Lactococcus lactis against oxidative stress.

Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to approximately 60 mM glutathione when this compound was added to the medium. Stationary-phase cells of strain SK11 grown in chemically defined medium supple...

Glutathione protects Lactococcus lactis against acid stress.

Previously we showed that glutathione (GSH) can protect Lactococcus lactis against oxidative stress (Y. Li et al., Appl. Environ. Microbiol. 69:5739-5745, 2003). In the present study, we show that the GSH imported by L. lactis subsp. cremoris SK11 or produced by engineered L. lactis subsp. cremoris NZ9000 can protect both strains against a long-term mild acid challenge (pH 4.0) and a short-term...

Instability in Lactococcus lactis

Molecular Mechanisms of Stress Resistance in Lactococcus lactis

Lactococcus is an economically important starter culture bacterium extensively used in the manufacture of the both soft and hard cheeses. During its growth and storage, and throughout cheese processing, it encounters a variety of stresses including osmotic, oxidative, temperature, acid and cell envelope stress. These stressors can cause damage to DNA, proteins, lipid membranes and peptidoglycan...