Characterization of Lactose-Fermenting Revertants from Lactose-Negative
            <i>Streptococcus lactis</i>
            C2 Mutants

Cords, B.R.; McKay, Larry L.

doi:10.1128/jb.119.3.830-839.1974

Cited by 43 publications

(32 citation statements)

References 25 publications

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“…A similar scheme for lactose fermentation by group N streptococci is suggested by complementation studies (1,10,28) of the lac-PTS (28,29,40) and by the fact that enzymes of the proposed pathways (5,20,30) are present in lactose-grown (and galactose-grown) organisms. However, with the exception of S. aureus, lac 6 Daggers (t) indicate compounds comprising the total PEP potential in starved cells ofS.…”

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confidence: 68%

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

Thompson¹

1979

J Bacteriol

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Starved cells of Streptococcus lactis ML3 grown previously on lactose, galactose, or maltose were devoid of adenosine 5'-triphosphate and 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 iodoacetateinhibited 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-,B-D-galactopyranosyl (1 -* 4')a-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, 2deoxy-D-glucose, methyl-,8-D-thiogalactopyranoside, and o-nitrophenyl-,f-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. P has not been isolated from any other micro-774 on July 31, 2020 by guest http://jb.asm.org/ Downloaded from .

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confidence: 68%

“…P-,3-gal, /3-D -Phosphogalactosidegalactohydrolase; HK, hexokinase; PK, pyruvatekinase; TMG, methyl-13-D -thiogalactopyranoside; 2-DG, 2-deoxy-D -glucose. organism, and although frequently inferred (7,10,30), the formation of this derivative by group N (or other) streptococci has not been reported.…”

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confidence: 97%

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

Thompson¹

1979

J Bacteriol

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“…The strong label associated with the traces of chromosomal DNA might indicate the presence of normally repressed chromosomal 6-P-/~-galactosidase genes, the presence of which has been postulated in some Strep. lactis strains (Cords & McKay 1974).…”

Section: Discussionmentioning

confidence: 99%

Identification of lactose fermentation plasmids of streptococcal dairy starter strains by Southern hybridization

Wright

Suominen

Sivelä

1986

Lett Appl Microbiol

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Twenty‐two strains of Streptococcus cremoris, seven strains of Streptococcus lactis and three strains of Streptococcus lactis subsp. diacetilactis, each with a different plasmid complement, were isolated from a starter culture used in a Finnish dairy plant. By using DNA‐DNA hybridization, with cloned 6‐P‐ß‐galactosidase gene of the Strep, lactis plasmid pLP712 as a probe, the lactose fermentation genes were located, in each strain, in the large ( 30 MD) plasmid.

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“…In addition to this secondary lactose transport system, this strain contains a functional lactose PTS but only traces of phospho-/J-galactosidase, resulting in the intracellular accumulation of high levels of lactose 6-phosphate [28]. Another case is found in 219 Lactococcus lactis strains cured of their typical lactose PTS plasmids [29][30][31][32]. Expression of a gene fusion of the Escherichia coli lacZ gene in such a lactose-deficient strain restored the capacity to utilize lactose, suggesting the presence of lactose permease [29].…”

Section: Lactose Transport Systemsmentioning

confidence: 99%

“…Expression of a gene fusion of the Escherichia coli lacZ gene in such a lactose-deficient strain restored the capacity to utilize lactose, suggesting the presence of lactose permease [29]. In addition, partial and complete revertants of these lactose-deficient Lactococcus lactis strains have been described with elevated levels of phospho-/3-galactosidase activity suggesting the induction of a second, cryptic PTS [30,31]. However, the possibility cannot be excluded that these transport systems arc specific for/~-glucosides or other sugars and coincidently translocate lactose.…”

Section: Lactose Transport Systemsmentioning

confidence: 99%

Genetics of lactose utilization in lactic acid bacteria

DEVOS¹,

Vaughan²

1994

FEMS Microbiology Reviews

100

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Lactose utilization is the primary function of lactic acid bacteria used in industrial dairy fermentations. The mechanism by which lactose is transported determines largely the pathway for the hydrolysis of the internalized disaccharide and the fate of the glucose and galactose moieties. Biochemical and genetic studies have indicated that lactose can be transported via phosphotransferase systems, transport systems dependent on ATP binding cassette proteins, or secondary transport systems including proton symport and lactose-galactose antiport systems. The genetic determinants for the group translocation and secondary transport systems have been identified in lactic acid bacteria and are reviewed here. In many cases the lactose genes are organized into operons or operon-like structures with a modular organization, in which the genes encoding lactose transport are tightly linked to those for lactose hydrolysis. In addition, in some cases the genes involved in the galactose metabolism are linked to or co-transcribed with the lactose genes, suggesting a common evolutionary pathway. The lactose genes show characteristic configurations and very high sequence identity in some phylogenetically distant lactic acid bacteria such as Leuconostoc and Lactobacillus or Lactococcus and Lactobacillus. The significance of these results for the adaptation of lactic acid bacteria to the industrial milk environment in which lactose is the sole energy source is discussed.

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Characterization of Lactose-Fermenting Revertants from Lactose-Negative Streptococcus lactis C2 Mutants

Cited by 43 publications

References 25 publications

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

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

Identification of lactose fermentation plasmids of streptococcal dairy starter strains by Southern hybridization

Genetics of lactose utilization in lactic acid bacteria

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