Fig 1.
Survival of L. rhamnosus CRL 1505 heated at different temperatures in potassium phosphate buffer 10mM pH 7.
Table 1.
Viability loss (cell death in log cycles) of L. rhamnosus CRL 1505 after heat shock (60°C, 5 min) in different media.
Fig 2.
Flow cytometry fluorescence density-plot analysis (Q1 dead, Q2 injured and Q3 live cell population) of L. rhamnosus CRL 1505 grown in MCM broth and harvested at stationary phase of growth.
Untreated cells (maintained at 37°C for 5 min) in potassium phosphate buffer (a) and after heat shock in different media: potassium phosphate buffer (b), MCM broth (c), MCM3 (d), MCM4 (e) and MCM5 (f). Values are the average of at least two experiments.
Fig 3.
Transmission electron micrographs (TEM) of thin sections of cells of L. rhamnosus CRL 1505.
The strain was maintained at 37°C for 5 min (a) and exposed to heat shock (b). V: membranous vesicles R: ribosomes CM: cytoplasmic membrane CW: cell wall F: fractures G: granular background in the cytoplasm, magnification of × 80,000. Presence of polyphosphate granules (PolyP) in the strain, magnification of × 50,000 (c).
Fig 4.
Electron micrographs (magnification of × 30,000) and polyP levels (AU, arbitrary units) of L. rhamnosus CRL 1505.
The strain was maintained at 37°C for 5 min (a) and thermally stressed (heat shock) in different media: phosphate buffer (b), MCM3 (c), MCM4 (d) MCM5(e).
Fig 5.
Flow cytometric fluorescence density-plot analysis (Q1 dead, Q2 injured and Q3 live cell population) of L. rhamnosus CRL 1505.
The strain was untreated (maintained at 37°C for 5 min) (a) and thermally stressed (heat shock) in phosphate buffer (b) and MCM3 (c). Values are the average of at least three independent assays.