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PubMed1996

Characterization of the lactose transport system in the strain Bifidobacterium bifidum DSM 20082.

Lactose was fermented but not assimilated by the strain Bifidobacterium bifidum DSM 20082. The sugar uptake was measured with lactose 14C. Km and V(max) values were respectively 2.6 mM and 12.11 nmol/min/mg of cell protein. The lactose transport system and the beta-D-galactosidase were stimulated when the cells were grown with lactose, but isopropyl-beta-D-thiogalactopyranoside had no effect. Lactose uptake was inhibited by compounds which interfered with proton and metal ionophore. Na+, Li+, or K+ did not affect incorporation of lactose. Furthermore, the lactose uptake decreased when an inhibitor of ATP synthesis was used. From the results of this study, the stain contained an active lactose transport system, probably a proton symport as described for Escherichia coli but with a different regulation system.

Bifidobacterium↗
PubMed1995

Effects of a dietary load of acid or base on changes induced by lactose in rats.

Feeding lactose or other slowly digestible carbohydrates to adult mammals may induce a variety of effects including hyperplasia and neoplasia. The most fundamental effect probably is the increased production in the large intestine of short-chain fatty acids (SCFA) resulting from increased fermentation of carbohydrate residues. To find out whether the increased production of these acidic compounds is involved in the induction of certain alterations caused by low-digestibility carbohydrates, the modifying effects of an acidifying (NH4Cl) or an alkalizing (KHCO3) diet supplement on lactose-induced changes in rats were studied. Three groups of 50 rats per sex were fed a 20% lactose diet unsupplemented or supplemented with 1% NH4Cl or 2% KHCO3, for at most 2.5 yr. One control group was fed the basal diet which contained wheat starch instead of lactose. Feeding lactose resulted in wet faecal pellets, reduced pH of the faeces, higher intake of food and water, lower body weights, increased caecal weights and fewer deaths. These effects were not significantly modified by NH4Cl or KHCO3. Feeding lactose increased urinary calcium levels, the effect being enhanced by NH4Cl and reduced by KHCO3. Lactose also tended to increase blood values of alkaline phosphatase and to decrease those for bicarbonate and base excess. These tendencies were generally more marked with NH4Cl, and less marked or absent with KHCO3. In addition, rats fed lactose showed decreased severity of nephrosis, increased mineralization and hyperplasia of the renal pelvic epithelium, and relatively high incidences of Leydig cell hyperplasia and neoplasia. NH4Cl supplementation was associated with a relatively small number of single and multiple tumours, with decreased incidences of hyperplasia and mineralization of the renal pelvis epithelium and with a markedly reduced incidence of proliferative changes in the adrenal medulla. With the KHCO3 supplement the incidences of Leydig cell proliferation and of bladder tumours were relatively high. These findings, in particular the differences between the diet groups in urinary calcium levels and possibly also the variations in blood levels of alkaline phosphatase, bicarbonate and base excess, suggest that the acidic end products of carbohydrate fermentation (SCFA) act as an acid load on the body.

Acid-Base Equilibrium↗
PubMed2004

Enhancement by lactose of intestinal alkaline phosphatase expression in rats.

Lactose promotes the intestinal absorption of calcium independent of the vitamin D endocrine system. This study investigated the effects of lactose on intestinal alkaline phosphatase (ALP) activity in rats. A total of 66 Sprague-Dawley strain female rats (10 weeks old) were divided into two groups: the control and the lactose groups. Animals in the lactose group were fed the experimental diet, in which the 10% of the diet was replaced with lactose. At 0, 3, 7, 14, and 21 days after beginning the experimental diets, rat intestinal segments from the duodenum, jejunum, and ileum were obtained immediately after sacrifice. The segments were slit open longitudinally, and the mucosa was scraped and used for the enzyme assay. The level of intestinal ALP activity in the jejunum from the lactose group was significantly higher than that from the control group. Two kinds of mRNA of rat intestinal ALP (RTIN-1 and RTIN-2) were detected by reverse transcription-polymerase chain reaction (RT-PCR). The level of mRNA expression in the jejunum from the lactose group was enhanced, especially of RTIN-2. This result was compatible with the results of enzymatic activity. These findings suggest that lactose affects intestinal Pi metabolism not only directly, but also in an indirect way via regulation of intestinal ALP expression, especially in the jejunum.

Alkaline Phosphatase↗
PubMed2004

Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility.

Physico-chemical properties of a substance including the compaction behaviour are directly connected with the crystalline structure. The aim of this work is to compare the compaction behaviour in a group of excipient and in this first part, to display the influence of lactose structures on the compressibility. alpha-Lactose monohydrate (LalphaM), anhydrous beta-lactose (LbetaA), anhydrous alpha-lactose (LalphaA) and partly amorphous lactose (FF) were compressed using instrumented presses to investigate the densification behaviour under pressure. Force-displacement curves were associated to two energy parameters, specific cycle energy and specific expansion energy. This approach was used to class the four lactose species. It is possible to differentiate three groups with the specific energy cycle, FF, LalphaA/LbetaA and LalphaM in decreasing order of this energy. At the same time, the values of specific expansion energy are relatively low for FF and LalphaA contrary to LalphaM and LbetaA. Then, Heckel's plots were obtained with two compact geometries and the mean yield pressure was calculated from the in-die-method and the out-of-die-method. Two lactoses seem to differ, LalphaM appears to be the most ductile whereas LalphaA is more brittle than the others. Finally, it is concluded, that in the case of lactoses, pseudopolymorphism seems to affect the compressibility more than anomerisation or partial amorphisation.

Compressive Strength↗
PubMed2003

Adaptation of a manometric biosensor to measure glucose and lactose.

A manometric sensor previously developed to measure urea was modified to measure glucose and lactose through enzymatic oxidation. Change in pressure in an enclosed cavity was correlated to the depletion of oxygen resulting from the enzymatic oxidation of glucose or lactose. The response of the sensor was linear and could be made adjustable over a large range by adjusting the amount of sample loaded into the fixed volume reactor. Because of the slow mutarotation of glucose, the oxidation of glucose was not allowed to proceed to completion. Therefore, the precision of the sensor (approximately 0.2 mM in a range from 0 to 5 mM) was limited by variations in the oxidation rate of glucose by glucose oxidase. Because the assay for lactose measured glucose subsequent to the hydrolysis of lactose by beta-galactosidase, the same degree of precision was observed in lactose. Milk lactose, typically at concentrations of about 150 mM, was estimated using the lactose assay after first diluting the samples. For many fluids such as milk, the use of manometric sensors for oxidizable substrates may be preferable to optical and electrochemical methods because they are robust and suffer a low degree of optical and chemical interferences. Glucose and lactose are representative of many important oxidizable substrates, which may be determined in this manner, many of which do not suffer from limitations caused by mutarotation. In theory, detection limits less than 1 microM may be achieved using these methods.

Animals↗
PubMed1991

Kinetic analysis of lactose exchange in proteoliposomes reconstituted with purified lac permease.

Lactose exchange catalyzed by purified lac permease reconstituted into proteoliposomes was analyzed with unequal concentrations of lactose on either side of the membrane and at low pH so as to prevent equilibration of the two pools. Exchange with external concentrations below 1.0 mM is a single-exponential process, and the apparent affinity constants for external and internal substrate are close to the apparent KMs reported for active transport and efflux, respectively [Viitanen, P.V., Garcia, M. L., & Kaback, H. R. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 1629]. At external lactose concentrations above 1.0 mM, a second kinetic pathway becomes evident with an apparent affinity constant of about 6 mM which is similar to the apparent KM for facilitated influx. A second pathway is not observed with respect to internal lactose even when the concentration is increased up to 80 mM. Furthermore, high internal or external lactose concentrations do not inhibit the exchange reaction. Biphasic kinetics with respect to external lactose are retained in a mutant permease that catalyzes exchange but is defective in H(+)-coupled lactose transport. It is suggested that lac permease has more than one binding site and that this may be the underlying reason for the biphasic kinetics observed for both exchange and H(+)-coupled lactose transport.

Biological Transport↗
PubMed1983

Effect of microflora and lactose on the absorption of calcium, phosphorus and magnesium in the hindgut of the rat.

For 4 weeks, 3-month old germfree (GF) and conventional (CV) rats were given a semi-synthetic diet sterilized by irradiation with or without 10% of lactose. During the 5th week, 0.2% of titanium oxide (TiO2) was added to the diet and the rats were killed at regular intervals throughout the light/dark cycle. The patterns of TiO2 and 45Ca excretion were similar, indicating that TiO2 was a good marker of unabsorbed calcium transit. The apparent absorption coefficient of calcium, magnesium and phosphorus was determined in the ileum, caecum, large intestine and faeces by the mineral/TiO2 ratio. The effects of microflora and lactose varied with the mineral and the digestive tract level studied. --In the small intestine, microflora had no effect on the apparent absorption of calcium and magnesium but did have an unfavorable influence on phosphorus absorption. Lactose increased calcium and magnesium absorption, and this increase was similar in GF and CV rats, but lactose had a favorable effect on phosphorus absorption only in CV rats. --In the caecum, microflora had an unfavorable effect on the apparent absorption of calcium and magnesium and a favorable effect on phosphorus absorption. The ingestion of lactose reduced calcium and magnesium absorption in the caecum of GF rats and phosphorus absorption in the caecum of CV animals. --In the colon, mineral absorption was not significant in either CV or GF rats receiving the lactose-free diets. Lactose ingestion caused the absorption of calcium, magnesium and phosphorus to rise significantly only in GF rats. This absorption contributed to the stronger effect of lactose on total calcium and phosphorus absorption in GF rats.

Animals↗
PubMed2002

Effects of ethanol to water ratio in feed solution on the crystallinity of spray-dried lactose.

In the present study, the effects of ethanol to water ratio in feed solution on the physical properties of spray-dried alpha-lactose monohydrate were evaluated. Crystallinity of the spray-dried lactose was determined by isothermal microcalorimetry (IMC) and by differential scanning calorimetry (DSC). Water content of the spray-dried lactose was determined by thermogravimetric analysis and the surface area was evaluated by Brunauer, Emmett, and Teller (BET) method. The crystallinity of spray-dried lactose varied from 0% to 100%, depending on the ratio of ethanol to water in the feed solution. Lactose spray dried from pure ethanol was 100% crystalline and contained hydrate water. Lactose spray dried from pure water was 100% amorphous. The feed solution substantially affected the ratio of surface water to hydrate water, as the content of surface water increased and hydrate water decreased, while the crystallinity of spray-dried lactose decreased. Surface area of the spray-dried lactose increased as a function of amorphous content.

Calorimetry↗
PubMed1991

Strains and species of lactic acid bacteria in fermented milks (yogurts): effect on in vivo lactose digestion.

Lactose in yogurt with live bacteria is better tolerated than lactose in other dairy foods, partly because of the activity of microbial beta-galactosidase (beta-gal), which digests lactose in vivo. To evaluate the ability of different strains and species of lactic acid bacteria to digest lactose in vivo, yogurts (containing mixtures of strains of Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp bulgaricus) and fermented milks (containing individual species of S thermophilus, L bulgaricus, L acidophilus, or Bifidobacterium bifidus) that varied in microbial beta-gal activity were produced. Selected products were fed to healthy people who cannot digest lactose, and breath hydrogen production was monitored. All yogurts dramatically and similarly improved lactose digestion, regardless of their total or specific beta-gal activity. The response to fermented milks varied from marginal improvement with B bifidus milk to nearly complete lactose digestion with L bulgaricus milk. The results suggest that total beta-gal was not the limiting factor in promoting lactose digestion, perhaps because of a limited rate of intracellular substrate transport.

Adult↗
PubMed1982

Involvement of a tyrosyl residue in the interaction of peanut lectin with lactose.

The role of a tyrosyl residue in the binding of Arachis hypogaea (peanut) agglutinin, AHA, to lactose has been studied using two techniques, titration of the phenolic hydroxyl group of the tyrosine residue and chemical modification of the tyrosine with iodine. More than three tyrosyl residues per mol of AHA were masked when AHA was titrated in the presence of lactose. Lactose also protected some tyrosyl residues of AHA from the modification with iodine. Upon interaction with lactose, AHA iodinated in the presence of lactose gave a UV-difference spectrum with similar peaks to those of native AHA, while AHA iodinated in the absence of lactose gave a spectrum without such peaks. Though not only native AHA but also iodinated AHA was completely adsorbed on a column of lactamyl-Sepharose 6B, equilibrium dialysis showed that the binding constant and the number of binding sites of native AHA and iodinated AHA with lactose were 4.3 x 10(3) and 3.0 x 10(3) M-1, and 3.2 and 1.8, respectively. These results suggest that about two of four sugar binding sites have tyrosyl residues which induce the UV-difference spectra upon binding with lactose, and that the iodination of these tyrosyl residues results in a decrease of the number of binding sites on AHA.

Arachis↗
PubMed1999

Effect of lactose administration in drinking water prior to and during feed withdrawal on Salmonella recovery from broiler crops and ceca.

Salmonella contamination of the chicken crop has been reported to increase markedly and significantly during feed withdrawal, probably due to coprophagy, and may contribute to carcass contamination at processing. The effect of prolonged lactose administration (2.5%) in the drinking water on the incidence of Salmonella recovery from broiler crops or ceca was evaluated in seven experiments. In these experiments, all or a percentage (providing seeders and contacts) of 7-wk-old broilers were challenged with approximately 1 x 108 cfu Salmonella enteritidis and provided lactose for 5 or 11 d prior to and during an 18 or 24 h feed withdrawal period. A small but significant lactose-mediated reduction in Salmonella contamination of crops was observed in one of two identical experiments with 18 h feed withdrawal. Extending the feed withdrawal period to 24 h did not improve the ability of lactose to affect Salmonella recovery from crops or ceca. Similarly, lactose did not affect Salmonella recovery when the percentage of birds challenged was reduced to 3 out of 16 and Salmonella recovery from crops or ceca of unchallenged, contact broilers was measured. Extending the duration of exposure to 2.5% lactose in the drinking water from 5 to 11 d did not improve the ability of lactose to affect Salmonella recovery. Taken together, these data suggest that provision of 2.5% lactose in the drinking water during the last 5 to 11 d of growout prior to slaughter will not be useful in an integrated Salmonella control program under commercial conditions.

Animal Husbandry↗
PubMed1994

Metabolites of lactose synthesis in milk from diabetic and nondiabetic women during lactogenesis II.

The concentrations of lactose, glucose, glucose 6-phosphate (G6P), glucose 1-phosphate (G1P), UDPglucose (UDPglc), UDPgalactose (UDPgal), and inorganic phosphate (P(i)) (metabolites in the lactose synthesis pathway) were measured in mammary secretion from nondiabetic (ND) and insulin-dependent diabetic (IDD) mothers during the first 10 days postpartum to determine their relationship with the amount of lactose synthesized and their association with the delay in lactose synthesis in IDD mothers. For all mothers the concentrations of all metabolites were low initially, and in ND mothers the first increases occurred as follows: lactose--day 2; glucose, G6P and P(i)--day 3; G1P and UDPglc--day 4; and UDPgal--day 6. The first increases for IDD mothers occurred 1-4 days later than for ND mothers. The concentrations of glucose, G6P, G1P, UDPglc, and P(i) were related to the amount of lactose synthesized. Since the rate of lactose synthesis and concentrations of other metabolites were less than half-maximal while the concentration of glucose was low, and since there was a delay in the increase in mammary gland concentrations of glucose in IDD mothers, it is concluded that glucose availability has the potential to play a role in the regulation of the rate of lactose synthesis at lactogenesis II.

Animals↗
PubMed1990

Extracellular beta-galactosidase activity of a Fibrobacter succinogenes S85 mutant able to catabolize lactose.

Fibrobacter succinogenes S85 is unable to grow with lactose as the source of carbohydrate, although it does exhibit low beta-galactosidase (EC 3.2.1.23) activity. Spontaneous mutants of strain S85 able to grow on lactose were isolated after spreading cells on a chemically defined agar medium with lactose as the carbohydrate source. A lactose-catabolizing isolate, designated L2, exhibited a sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profile and an immunoblot profile with polyclonal antibodies to whole cells of S85 which were identical to those observed for S85. Strain L2 exhibited both cell-associated and extracellular beta-galactosidase activity with either p-nitrophenyl-beta-D-galactopyranoside or lactose as the substrate. The cell-associated enzyme exhibited the greatest activity in the periplasmic space. Enzyme production was partially inhibited by glucose. The beta-galactosidase was activated by divalent cations and exhibited a pH optimum of 6.5. Analysis of the extracellular culture fluid revealed that glucose derived from the hydrolysis of lactose was used for growth, but galactose was not metabolized further. Cells were unable to take up the lactose analog, methyl-beta-D-thiogalactopyranoside. These data suggest that beta-galactosidase of F. succinogenes L2 cleaves lactose outside the cells and that the glucose released is catabolized while the galactose accumulates in the extracellular culture fluid.

Animals↗
PubMed2005

Role of the bga1-encoded extracellular {beta}-galactosidase of Hypocrea jecorina in cellulase induction by lactose.

Lactose is the only soluble and economically feasible carbon source for the production of cellulases or heterologous proteins regulated by cellulase expression signals by Hypocrea jecorina (Trichoderma reesei). We investigated the role of the major beta-galactosidase of H. jecorina in lactose metabolism and cellulase induction. A genomic copy of the bga1 gene was cloned, and this copy encodes a 1,023-amino-acid protein with a 20-amino-acid signal sequence. This protein has a molecular mass of 109.3 kDa, belongs to glycosyl hydrolase family 35, and is the major extracellular beta-galactosidase during growth on lactose. Its transcript was abundant during growth on l-arabinose and l-arabinitol but was much less common when the organism was grown on lactose, d-galactose, galactitol, d-xylose, and xylitol. Deltabga1 strains grow more slowly and accumulate less biomass on lactose, but the cellobiohydrolase I and II gene expression and the final cellulase yields were comparable to those of the parental strain. Overexpression of bga1 under the control of the pyruvate kinase promoter reduced the lag phase, increased growth on lactose, and limited transcription of cellobiohydrolases. We detected an additional extracellular beta-galactosidase activity that was not encoded by bga1 but no intracellular beta-galactosidase activity. In conclusion, cellulase production on lactose occurs when beta-galactosidase activity levels are low but decreases as the beta-galactosidase activities increase. The data indicate that bga1-encoded beta-galactosidase activity is a critical factor for cellulase production on lactose.

Cellulase↗
PubMed1979

Lactose metabolism in Streptococcus lactis: phosphorylation of galactose and glucose moieties in vivo.

Starved cells of Streptococcus lactis ML3 grown previously on lactose, galactose, or maltose were devoid of adenosine 5'-triphosphate contained only three glycolytic intermediates: 3-phosphoglycerate, 2-phosphoglycerate, and phosphoenolpyruvate (PEP). The three metabolites (total concentration, ca 40 mM) served as the intracellular PEP potential for sugar transport via PEP-dependent phosphotransferase systems. When accumulation of [14C]lactose by iodoacetate-inhibited starved cells was abolished within 1 s of commencement of transport, a phosphorylated disaccharide was identified by autoradiography. The compound was isolated by ion-exchange (borate) chromatography, and enzymatic analysis showed that the derivative was 6-phosphoryl-O-beta-D-galactopyranosyl (1 leads to 4')-alpha-D-glucopyranose (lactose 6-phosphate). After maximum lactose uptake (ca. 15 mM in 15 s) the cells were collected by membrane filtration and extracted with trichloroacetic acid. Neither free nor phosphorylated lactose was detected in cell extracts, but enzymatic analysis revealed high levels of galactose 6-phosphate and glucose 6-phosphate. The starved organisms rapidly accumulated glucose, 2-deoxy-D-glucose, methyl-beta-D-thiogalactopyranoside, and o-nitrophenyl-beta-D-galactopyranoside in phosphorylated form to intracellular concentrations of 32, 32, 42, and 38.5 mM, respectively. In contrast, maximum accumulation of lactose (ca. 15 mM) was only 40 to 50% that of the monosaccharides. From the stoichiometry of PEP-dependent lactose transport and the results of enzymatic analysis, it was concluded that (i) ca. 60% of the PEP potential was utilized via the lactose phosphotransferase system for phosphorylation of the galactosyl moiety of the disaccharide, and (ii) the residual potential (ca. 40%) was consumed during phosphorylation of the glucose moiety.

Biological Transport, Active↗
PubMed1984

Properties of a Streptococcus lactis strain that ferments lactose slowly.

Streptococcus lactis 7962, which ferments lactose slowly, has a lactose phosphoenolpyruvate-dependent phosphotransferase system and low phospho-beta-galactosidase activity, in addition to high beta-galactosidase activity. Lactose 6'-phosphate accumulated to a high concentration (greater than 100 mM) in cells growing on lactose. In contrast, lactic streptococci, which ferment lactose rapidly and use only the lactose-phosphotransferase system for uptake, contained high phospho-beta-galactosidase activity and low concentrations (0.9 to 1.6 mM) of lactose 6'-phosphate. It is concluded that rate-limiting phospho-beta-galactosidase activity is primarily responsible for defective lactose metabolism in S. lactis 7962.

Fermentation↗
PubMed1985

Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities.

A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose-phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of [14C]lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution 31P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM. We conclude from our data that phosphorylation of glucose by S. lactis 133 can be mediated by only two mechanisms: (i) via ATP-dependent glucokinase, and (ii) by the phosphoenolpyruvate-dependent mannose-PTS system.

Biological Transport↗
PubMed1987

Bioenergetic consequences of lactose starvation for continuously cultured Streptococcus cremoris.

Streptococcus cremoris cells that had been grown in a chemostat were starved for lactose. The viability of the culture remained essentially constant in the first hours of starvation and subsequently declined logarithmically. The viability pattern during starvation varied with the previously imposed growth rates. The death rates were 0.029, 0.076, and 0.298 h-1 for cells grown at dilution rates of 0.07, 0.11 and 0.38 h-1, respectively. The proton motive force and the pools of energy-rich phosphorylated intermediates in cells grown at a dilution rate of 0.10 h-1 fell to zero within 2 h of starvation. The culture, however, remained fully viable for at least 20 h, indicating that these energy-rich intermediates are not crucial for survival during long-term lactose starvation. Upon starvation, the intracellular pools of several amino acids depleted with the proton motive force, while large concentration gradients of the amino acids alanine, glycine, aspartate, and glutamate were retained for several hours. A quantitative analysis of the amino acids released indicated that nonspecific protein degradation was not a major cause of the loss in viability. The response of the energy metabolism of starved S. cremoris cells upon refeeding with lactose was monitored. Upon lactose starvation, the glycolytic activity and the rate of proton motive force generation decreased rapidly but the steady-state level of the proton motive force decreased significantly only after several hours. The decreasing steady-state level of the proton motive force and consequently the capacity to accumulate amino acids after the addition of lactose correlated well with the loss of viability. The response of the energy metabolism of starved S. cremoris cells upon refeeding with lactose was monitored. Upon lactose starvation, the glycolytic activity and the rate of proton motive force generation decreased rapidly but the steady-state level of the proton motive force decreased significantly only after several hours. The decreasing steady-state level of the proton motive force and consequently the capacity to accumulate amino acids after the addition of lactose correlated well with the loss of viability. It is concluded that a regulatory loss of glycolytic capacity has pivotal role in the survival of S. cremoris under the conditions used.

Adenosine Triphosphate↗