The influence of phage-assisted lysis of Lactococcus lactis subsp. lactis ML8 on cheddar cheese ripening

Crow, Vaughan L.; Martley, Frank G.; Coolbear, Tim; Roundhill, S. J.

doi:10.1016/0958-6946(95)00022-u

Cited by 71 publications

(39 citation statements)

References 29 publications

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“…Since we also observed that the extent of starter bacteria Iysis was related to the phage levels, we can conclude that the higher the cell Iysis, the higher was the rate of formation of small peptides and free arnino acids. These results are in agreement with previous studies (Chapot-Chartier et al, 1994;Wilkinson et al, 1994;Crow et al, 1995b) which also established a relationship between the lysis of starter bacteria and the proteolysis rate.…”

supporting

confidence: 94%

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Kawabata

Vassal

Bars

et al. 1997

Lait

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Summary -The autolysis of starter bacteria during chee se ripening results in the release of intracellular enzymes, especially peptidases, into the curd and in consequence is expected to accelerate and enhance the development of cheese flavour. In the course of a series of cheese assays with the nonautolytic Lactococcus lactis NC00763 strain, the presence of a homologous bacteriophage was encountered. The phage was present at different levels which allowed us to evaluate the impact of the extent of starter bacteria Iysis on Saint-Paulin-type cheese proteolysis during ripening. We estimated bacterial Iysis by viable cell enumeration and electron microscopy observations over a 2-month ripening period. On the same cheeses, we have estimated proteolysis by measuring soluble nitrogen (SN) and phosphotun~stic acid-soluble nitrogen (PT A-N) and by quantifying free amino acids. For phage levels up to 10 0 pfu/g of cheese, the pH and dry matter values were in the standard range, whereas for a higher phage level incorrect acidification was observed. The ex te nt of starter Iysis increased with the phage level and it was also correlated with the rate of formation of small peptides and free amino acids. After 2 months of ripening, the PTA-N value was three-fold higher and the total free amino acid content was seven-fold higher in the cheese with a phage level of 10 10 pfu/g than in the control cheeses. These results confirm that the early Iysis of starter bacteria allows the release of intracellular peptidases which are active in cheese, and that the extent of starter Iysis can be correlated with the proteolysis rate.Lactococcus lactis / cheese ripening / Iysis / phage / proteolysis Résumé -Lyse de Lactococcus lactis induite par des phages au cours de l'affinage de fromages de type Saint-Paulin et impact sur la protéolyse.L'autolyse des bactéries lactiques du levain résulte en la libération des enzymes intracellulaires, en particulier des peptidases, dans le

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supporting

confidence: 94%

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Kawabata

Vassal

Bars

et al. 1997

Lait

View full text Add to dashboard Cite

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“…It is recognized that after autolysis, these intracellular peptidases act by degrading caseinderived peptides in cheese, contributing to the desirable flavor characteristics in the final cheese product (22,35). Indeed, various studies demonstrate the association of starter cell lysis with increased proteolysis and/or flavor development (8,23,39). As a result, a number of surveys comparing autolysis of lactococcal strains have been conducted (8,16,26,34) and the autolytic systems of several strains have been characterized (5,27,29).…”

mentioning

confidence: 99%

“…Indeed, various studies demonstrate the association of starter cell lysis with increased proteolysis and/or flavor development (8,23,39). As a result, a number of surveys comparing autolysis of lactococcal strains have been conducted (8,16,26,34) and the autolytic systems of several strains have been characterized (5,27,29). It is noteworthy that alternative methods to accelerate ripening are available, and these include the addition of exogenous proteinase or peptidase preparations to the curd at the salting stage (17,37) or the exploitation of bacteriocin-producing starter strains to mediate targeted lysis of individual starter strains (24).…”

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confidence: 99%

Investigation of the Relationship between Lysogeny and Lysis of Lactococcus lactis in Cheese Using Prophage-Targeted PCR

O’Sullivan

Ross

Fitzgerald

et al. 2000

Appl Environ Microbiol

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The ability of lactococcal strains to lyse (and release intracellular enzymes) during cheese manufacture can be a very desirable trait and has been associated with improvement in flavor and acceleration of cheese ripening. Using a laboratory-scale cheese manufacturing assay, the autolytic behavior of 31 strains of Lactococcus lactis was assessed. In general, marked variation was observed between strains with a 20-fold difference between the best and worst lysing strains based on the release of the intracellular enzyme lactate dehydrogenase. In a parallel experiment, the genomes of these strains were examined for the presence of prophage integrase (int) sequences by using conserved primer sequences from known lysogenic phage. Results demonstrated that the lytic behavior of lactococcal starter strains significantly correlates with the presence of prophage sequences. These results highlight not only the contribution of prophage to starter cell lysis but also the potential of PCR as a useful initial screen to assess strains for this important industrial trait.

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“…The activity of these enzymes can therefore be enhanced by better accessibility to their substrates, proteins, lipids, or carbohydrates from the milk. It has been shown that the main consequence of cell autolysis in cheese is peptidolysis acceleration, leading to an increased rate of free amino acid production and to a decrease in bitter taste (2,3,13,16,25,32,34,35,55).…”

mentioning

confidence: 99%

“…Autolysis was investigated by physiological studies and also by analysis of the peptidoglycan hydrolase content. The autolytic character of Lactococcus and Lactobacillus strains was studied in liquid medium (2,3,28,33,41,54) and for some of them during cheese ripening (5,13,16,32,35,53,55). It appears to vary from strain to strain.…”

mentioning

confidence: 99%

The Streptococcus thermophilus Autolytic Phenotype Results from a Leaky Prophage

Husson-Kao

Mengaud

Cesselin³

et al. 2000

Appl Environ Microbiol

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Streptococcus thermophilus autolytic strains are characterized by a typical bell-shaped growth curve when grown under appropriate conditions. The cellular mechanisms involved in the triggering of lysis and the bacteriolytic activities of these strains were investigated in this study. Lactose depletion and organic solvents (ethanol, methanol, and chloroform) were shown to trigger a premature and immediate lysis of M17 exponentially growing cells. These factors and compounds are suspected to act by altering the cell envelope properties, causing either the permeabilization (organic solvents) or the depolarization (lactose depletion) of the cytoplasmic membrane. The autolytic character was shown to be associated with lysogeny. Phage particles, most of which were defective, were observed in the culture supernatants after both mitomycin C-induced and spontaneous lysis. By renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a bacteriolytic activity was detected at 31 kDa exclusively in the autolytic strains. This enzyme was detected during both growth and spontaneous lysis with the same intensity. We have shown that it was prophage encoded and homologous to the endolysin Lyt51 of the streptococcal temperate bacteriophage 01205 (M. Sheehan, E. Stanley, G. F. Fitzgerald, and D. van Sinderen, Appl. Environ. Microbiol. 65:569-577, 1999). It appears from our results that the autolytic properties are conferred to the S. thermophilus strains by a leaky prophage but do not result from massive prophage induction. More specifically, we propose that phagic genes are constitutively expressed in almost all the cells at a low and nonlethal level and that lysis is controlled and achieved by the prophage-encoded lysis proteins.Autolysis of lactic acid bacteria used as starters appears to be a crucial step in the flavor development of fermented dairy products (12,15). It indeed causes the opening of cells and the subsequent release into the curd of intracellular enzymes that are involved in the flavor compound formation. The activity of these enzymes can therefore be enhanced by better accessibility to their substrates, proteins, lipids, or carbohydrates from the milk. It has been shown that the main consequence of cell autolysis in cheese is peptidolysis acceleration, leading to an increased rate of free amino acid production and to a decrease in bitter taste (2,3,13,16,25,32,34,35,55).Bacterial autolysis results from the degradation of the peptidoglycan, which is the major structural component of the bacterial cell wall, by enzymes called peptidoglycan hydrolases. Bacteria synthesize their own peptidoglycan hydrolases, named autolysins (45). These cell wall-associated enzymes are potentially lethal for the cell and thus require stringent regulation. It has been proposed that autolysins are involved in different cellular processes including cell wall expansion and turnover, cell division, and transformation (47). Autolysis would result from an uncontrolled action of the bacterial autolysins after inhibition of peptid...

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The influence of phage-assisted lysis of Lactococcus lactis subsp. lactis ML8 on cheddar cheese ripening

Cited by 71 publications

References 29 publications

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Investigation of the Relationship between Lysogeny and Lysis of Lactococcus lactis in Cheese Using Prophage-Targeted PCR

The Streptococcus thermophilus Autolytic Phenotype Results from a Leaky Prophage

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