Effects of pressure on cell morphology and cell division of lactic acid bacteria

Abstract

The effect of pressure and temperature on the growth of the mesophilic lactic acid bacteria Lactococcus lactis and Lactobacillus sanfranciscensis was studied. Both strains were piezosensitive. Lb. sanfranciscensis failed to grow at 50 MPa and the growth rate of Lc. lactis at 50 MPa was less than 30% of that at atmospheric pressure. An increase of growth temperature did not improve the piezotolerance of either organism. During growth under high-pressure conditions, the cell morphology was changed, and the cells were elongated as cell division was inhibited. At atmospheric pressure, temperatures above the optimal temperature for growth caused a similar effect on cell morphology and cell division in both bacteria as that observed under high-pressure conditions. The segregation and condensation of chromosomal DNA were observed by DAPI staining and occurred normally at high-pressure conditions independent of changes in cell morphology. Immunofluorescence microscopy of Lc. lactis cells demonstrated an inhibitory effect of high pressure on the formation of the FtsZ ring and this inhibition of the FtsZ ring formation is suggested to contribute to the altered cell morphology and growth inhibition induced by high pressure.

Preservation under pressure (hyperbaric storage) at 25°C, 30°C and 37°C of a highly perishable dairy food and comparison with refrigeration

“…Considering these results, HS at all tested conditions resulted in lower to equal microbial LAB counts, compared to samples stored at refrigeration. These results are according to Molina-Höppner, Sato, Kato, Gänzle, and Vogel (2003), who studied the pressure effect from 0.1 to 100 MPa, for 20 and 48 hours at 30°C on two mesophile LAB, Lactococcus lactis and Lactobacillus sanfranciscensis growth rates, concluding that 50 MPa were able to inhibit Lb. sanfranciscensis growth, and reduce Lc.…”

The inhibitory activity of wine yeast starters on malolactic bacteria

“…Microbial survival during these processes depends greatly on the ability of a strain to adapt and become more tolerant to the environmental conditions (Guzzo et al, 2000;Molina-Hoppner et al, 2003). In the present study, this was exemplified by the modifications in cell morphology seen under exposure to the inhibitory compounds produced by the yeast.…”

An SOS Response Induced by High Pressure inEscherichia coli

“…In addition, no effect of the absence of SulA or RecA on cell filamentation induced by growth at permissive pressures was observed (unpublished data). Although both Kawarai et al (33) and Molina-Hoppner et al (38) suggested that elongation results from direct high-pressure inhibition of FtsZ ring formation, we believe that high-pressure-induced cell elongation in this respect resembles the "transient filamentation" phenotype observed by Gottesman et al (25) after UV treatment, which was also shown to be independent of SulA. Also the recent finding of Bidle and Bartlett (11) that recD of the piezotolerant deep-sea isolate SS9 allows E. coli to grow at high pressures without filamentation is more compatible with a model in which pressure-induced filamentation is mediated by the SOS response than with the model assuming a direct effect of pressure on FtsZ, because RecD is involved in DNA recombination and repair.…”

“…Another typical pressure-related phenomenon is cell filamentation in piezosensitive bacteria growing at permissive high pressures (Յ50 MPa) (38,55). Interestingly, we found pressure-induced cell elongation also to occur in the first hours after sublethal high-pressure treatment (unpublished data).…”