Changes in Permeability and Ultrastructure of Starved Streptococcus Lactis in Relation to Survival

Thomas, T. D.; Lyttleton, Pamela; Williamson, Keith I.; Batt, Richard D.

doi:10.1099/00221287-58-3-381

Cited by 15 publications

(12 citation statements)

References 8 publications

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“…Therefore it seemed unlikely that Streptococcus lactis was capable of synthesizing these polymers which had been reported as present in many bacterial species. Electron micrographs of thin sections showed no evidence of polyphosphate granules (Thomas & Batt, 1969).…”

Section: )-Resultsmentioning

confidence: 99%

“…Since these compounds are known to have important structural and physiologica1 roles in bacterial membranes (Brown, 1964;Salton, 1967) any breakdown of phospholipids may be expected to impair permeability barriers. The possible significance of these observations in the survival of starved S. Zactis is discussed elsewhere (Thomas & Batt, 1969).…”

Section: Discussionmentioning

confidence: 99%

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Degradation of Cell Constituents by Starved Streptococcus lactis in Relation to Survival

Thomas

Batt

1969

Journal of General Microbiology

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SUMMARYStreptococcus lactis organisms were grown in lactose-limited batch culture and transferred, after washing, to phosphate buffer at the growth temperature. Soluble protein was released from viable organisms into the suspending buffer and the intracellular free amino acid pool declined steadily with the components appearing in the suspending buffer; a net increase in the total amount of free amino acid indicated some protein hydrolysis. RNA was hydrolysed, resulting in the release of u.v.-absorbing bases and ribose from the organisms, Conditions which promoted rapid RNA breakdown also produced rapid death rates and long cell division lags in surviving organisms. After 28 hr starvation in buffer containing Mg2+, the bacterial dry wt decreased by 26 %; loss of RNA, protein and free amino acids accounted for 10.3 %, 7-3 % and 2.7 % of the total bacterial mass loss. The products of polymer hydrolysis appeared to be released in an undegraded form into the external buffer and there was no appreciable formation of lactate, ammonia or volatile fatty acids, possibly indicating the absence of any important endogenous energy sources. There was no appreciable degradation of DNA or carbohydrate but phospholipid was broken down on prolonged starvation. No polyglucose or poly-@-hydroxybutyrate was detected in the organisms.

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Section: )-Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Degradation of Cell Constituents by Starved Streptococcus lactis in Relation to Survival

Thomas

Batt

1969

Journal of General Microbiology

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“…The only morphological alteration that could be detected was the degradation of ribosomes leading to clearer regions in the cytoplasm, characteristic of bacteria under starvation (Thomas et al, 1969).…”

Section: Estimation Of Starter Bacteria Iysismentioning

confidence: 99%

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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“…Starved S. Zactis is capable of fermenting glucose at a maximum rate of about 843pmolelmg. dry wt bacterialhr (Thomas & Batt, 19694. …”

Section: Resultsmentioning

confidence: 99%

“…After 120hr starvation at a feed rate of 0.25pmole glucose/mg. dry wt bacteria/hr (viability 40 %), organisms were harvested for examination by electron microscopy (Thomas & Batt, 19694. Starved cultures were progressively diluted but since survival was independent of bacterial density in the presence of added Mg2+ (Thomas & Batt, 1968), this should not have influenced the present results.…”

Section: T D Thomas a N D R D Battmentioning

confidence: 99%

Metabolism of Exogenous Arginine and Glucose by Starved Streptococcus Lactis in Relation to Survival

Thomas

Batt

1969

Journal of General Microbiology

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SUMMARYArginine or glucose accelerated death of Streptococcus lactis starved in phosphate buffer. Both substrates were metabolized at linear but different rates and the rate of ATP production from glucose metabolism was about 7-5 times that for arginine metabolism. Mg2+ reduced glucose-accelerated death and abolished arginine-accelerated death to prolong survival. When glucose was fed continuously to organisms starved in phosphate buffer containing Mg2+, survival was related to the rate of glucose addition and hence to the rate of metabolism. By feeding low concentrations of glucose, the viability of most of the population was extended from about I to 4 days. The maintenance energy requirement appeared to be in the region of 0.045 to 0.09 mg. glucose/mg. dry wt bacteria/hr. The glycolytic activity of starved organisms declined at varying rates depending on the starvation environment but could not be correlated directly with loss of viability. Exogenous arginine substantially reduced the lethal effect of adverse pH values.

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Changes in Permeability and Ultrastructure of Starved Streptococcus Lactis in Relation to Survival

Cited by 15 publications

References 8 publications

Degradation of Cell Constituents by Starved Streptococcus lactis in Relation to Survival

Degradation of Cell Constituents by Starved Streptococcus lactis in Relation to Survival

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

Metabolism of Exogenous Arginine and Glucose by Starved Streptococcus Lactis in Relation to Survival

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