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María J. Yebra - One of the best experts on this subject based on the ideXlab platform.
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The Lactose Operon from Lactobacillus casei is involved in the transport and metabolism of the human milk oligosaccharide core-2 N-acetyllactosamine
Scientific Reports, 2018Co-Authors: Gonzalo N. Bidart, Gaspar Pérez-martínez, Jesús Rodríguez-díaz, María J. YebraAbstract:The Lactose Operon ( lacTEGF ) from Lactobacillus casei strain BL23 has been previously studied. The lacT gene codes for a transcriptional antiterminator, lacE and lacF for the Lactose-specific phosphoenolpyruvate: phosphotransferase system (PTS^Lac) EIICB and EIIA domains, respectively, and lacG for the phospho-β-galactosidase. In this work, we have shown that L. casei is able to metabolize N -acetyllactosamine (LacNAc), a disaccharide present at human milk and intestinal mucosa. The mutant strains BL153 ( lacE ) and BL155 ( lacF ) were defective in LacNAc utilization, indicating that the EIICB and EIIA of the PTS^Lac are involved in the uptake of LacNAc in addition to Lactose. Inactivation of lacG abolishes the growth of L. casei in both disaccharides and analysis of LacG activity showed a high selectivity toward phosphorylated compounds, suggesting that LacG is necessary for the hydrolysis of the intracellular phosphorylated Lactose and LacNAc. L. casei ( lacAB ) strain deficient in gaLactose-6P isomerase showed a growth rate in Lactose (0.0293 ± 0.0014 h^−1) and in LacNAc (0.0307 ± 0.0009 h^−1) significantly lower than the wild-type (0.1010 ± 0.0006 h^−1 and 0.0522 ± 0.0005 h^−1, respectively), indicating that their gaLactose moiety is catabolized through the tagatose-6P pathway. Transcriptional analysis showed induction levels of the lac genes ranged from 130 to 320–fold in LacNAc and from 100 to 200–fold in Lactose, compared to cells growing in glucose.
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sorbitol production from Lactose by engineered lactobacillus casei deficient in sorbitol transport system and mannitol 1 phosphate dehydrogenase
Applied Microbiology and Biotechnology, 2010Co-Authors: Reinout De Boeck, Inmaculada Nadal, Vicente Monedero, Gaspar Perezmartinez, Luz Adriana Sarmientorubiano, María J. YebraAbstract:Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the Lactose Operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert Lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of Lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate.
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Diacetyl and acetoin production from whey permeate using engineered Lactobacillus casei
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Inmaculada Nadal, Juan Rico, Gaspar Pérez-martínez, María J. Yebra, Vicente MonederoAbstract:The capability of Lactobacillus casei to produce the flavor-related compounds diacetyl and acetoin from whey permeate has been examined by a metabolic engineering approach. An L. casei strain in which the ilvBN genes from Lactococcus lactis, encoding acetohydroxyacid synthase, were expressed from the Lactose Operon was mutated in the lactate dehydrogenase gene (ldh) and in the pdhC gene, which codes for the E2 subunit of the pyruvate dehydrogenase complex. The introduction of these mutations resulted in an increased capacity to synthesize diacetyl/acetoin from Lactose in whey permeate (1,400 mg/l at pH 5.5). The results showed that L. casei can be manipulated to synthesize added-value metabolites from dairy industry by-products.
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sorbitol synthesis by an engineered lactobacillus casei strain expressing a sorbitol 6 phosphate dehydrogenase gene within the Lactose Operon
Fems Microbiology Letters, 2005Co-Authors: Lorenzo Nissen, Gaspar Perezmartinez, María J. YebraAbstract:Sorbitol is claimed to have important health-promoting effects and Lactobacillus casei is a lactic acid bacterium relevant as probiotic and used as a cheese starter culture. A sorbitol-producing L. casei strain might therefore be of considerable interest in the food industry. A recombinant strain of L. casei was constructed by the integration of a d-sorbitol-6-phosphate dehydrogenase-encoding gene (gutF) in the chromosomal Lactose Operon (strain BL232). gutF expression in this strain followed the same regulation as that of the lac genes, that is, it was repressed by glucose and induced by Lactose. 13C-nuclear magnetic resonance analysis of supernatants of BL232 resting cells demonstrated that, when pre-grown on Lactose, cells were able to synthesize sorbitol from glucose. Inactivation of the l-lactate dehydrogenase gene in BL232 led to an increase in sorbitol production, suggesting that the engineered route provides an alternative pathway for NAD+ regeneration.
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engineering sorbitol 6 phosphate dehydrogenase encoding gene in the Lactose Operon of lactobacillus casei
2005Co-Authors: Lorenzo Nissen, María J. Yebra, Barbara Sgobarti, Gaspar Perez MartinezAbstract:BL233: L.casei BL232 with ldhL::Prv300 BL234: L.casei BL232 with gutF::pRV300 in gut Operon Bacterial strains, plasmids, primers and growth conditions L. casei strains were grown in MRS medium or MRS fermentation medium supplemented different carbohydrates at 37oC under static conditions. Escherichia coli DH5 was grown LB medium at 37oC under agitation. When required erythromycin and ampicillin were added to the media.
Michael J Gasson - One of the best experts on this subject based on the ideXlab platform.
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exploitation of a chromosomally integrated Lactose Operon for controlled gene expression in lactococcus lactis
Fems Microbiology Letters, 1996Co-Authors: John Payne, H G Griffin, Caroline A Maccormick, Michael J GassonAbstract:Lactococcus lactis MG5267 is a plasmid-free strain in which the Lactose Operon is integrated in the bacterial chromosome. The chromosomal lacG gene which encodes phospho-β-galactosidase was inactivated by a double cross-over integration event. Unexpectedly, the resultant mutant was shown to retain a Lac-positive phenotype. The lysin gene from Listeria monocytogenes bacteriophage LM-4 was subsequently integrated into the chromosome of this strain such that expression of the heterologous gene was mediated by the Lactose Operon promoter. Expression of the lysin gene was shown to be regulated by growth on Lactose. This represents an important strategy for the controlled and stabilised expression of biotechnologically useful genes in L lactis.
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construction of a food grade host vector system for lactococcus lactis based on the Lactose Operon
Fems Microbiology Letters, 1995Co-Authors: Caroline A Maccormick, H G Griffin, Michael J GassonAbstract:A plasmid-based food-grade vector system was developed for Lactococcus lactis by exploiting the genes for Lactose metabolism. L. lactis MGS267 is a plasmid-free strain containing the entire Lactose Operon as a chromosomal insertion. The lacF gene was deleted from this strain by a double cross-over homologous recombination event. The lacF-deficient strain produced a Lac− phenotype on indicator agar. A cloned copy of the lacF gene expressed on a plasmid was capable of complementing the lacF-deficient strain resulting in a Lac+ phenotype. This stably maintained system fits the requirements of a self-selecting vector system and has the potential to be exploited in the food industry.
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research letterconstruction of a food grade host vector system for lactococcus lactis based on the Lactose Operon
Fems Microbiology Letters, 1995Co-Authors: Caroline A Maccormick, H G Griffin, Michael J GassonAbstract:A plasmid-based food-grade vector system was developed for Lactococcus lactis by exploiting the genes for Lactose metabolism. L. lactis MGS267 is a plasmid-free strain containing the entire Lactose Operon as a chromosomal insertion. The lacF gene was deleted from this strain by a double cross-over homologous recombination event. The lacF-deficient strain produced a Lac− phenotype on indicator agar. A cloned copy of the lacF gene expressed on a plasmid was capable of complementing the lacF-deficient strain resulting in a Lac+ phenotype. This stably maintained system fits the requirements of a self-selecting vector system and has the potential to be exploited in the food industry.
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the regulation of expression of the lactococcus lactis Lactose Operon
Letters in Applied Microbiology, 1993Co-Authors: H G Griffin, Michael J GassonAbstract:Translational gene fusions between the Escherichia coli beta-galactosidase (lacZ) gene and the Lactococcus lactis Lactose Operon were constructed such that transcription from the Lactose Operon promoter could be assessed by measuring beta-galactosidase activity. The level of beta-galactosidase activity was up to 2.5-fold lower when MG5267 cells, which contain a chromosomal copy of the Lactose Operon, were grown in glucose compared to those grown in Lactose. A greater degree of repression was seen in cells containing the multi-copy plasmid-encoded repressor than in those with only the single-copy chromosomal gene, indicating that the repressor protein is at least partly responsible for the reduction in expression when the cells are grown in glucose (i.e. in the absence of inducer). However, the beta-galactosidase activity was found to be 5.5-fold lower in glucose than in Lactose in cells which lacked a fully functional Lactose Operon. The decrease in expression was shown to be due to glucose repression. The levels of expression when the cells were grown in glucose were considerably higher for MG5267 than for MG1363 suggesting perhaps that a product of the chromosomally-encoded Operon in MG5267 has a positive effect on transcription.
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characterization of the lactococcus lactis Lactose Operon promoter contribution of flanking sequences and lacr repressor to promoter activity
Journal of Bacteriology, 1992Co-Authors: R J Van Rooijen, Michael J Gasson, W M De VosAbstract:We determined the location, activity, and regulation of the promoter of the Lactococcus lactis 8-kb Lactose Operon (lacABCDFEGX), which encodes the enzymes of the Lactose phosphotransferase system and the tagatose 6-phosphate pathway. The lac promoter sequence corresponds closely to the consensus promoter described for gram-positive bacteria and is located in a back-to-back configuration with the promoter of the divergently transcribed lacR gene, which encodes the LacR repressor. The transcription start sites used under induced (Lactose) and noninduced (glucose) conditions were determined. The minimal promoter region that could be isolated on a single restriction fragment included sequences ranging from -75 to +42. The effect of the presence of flanking sequences and the lacR gene on promoter activity and regulation was studied in Escherichia coli and L. lactis strains by using transcriptional fusions with promoterless chloramphenicol acetyltransferase reporter genes. The results showed that transcriptional regulation of the lac Operon is mediated by the interaction between the LacR repressor, the lac promoter, and sequences in the noncoding region between the lacR and lacA genes. Sequences flanking the minimal promoter region appeared to enhance lac promoter activity much more in L. lactis (5- to 38-fold) than in E. coli (1.3- to 5-fold). Images
Gaspar Perezmartinez - One of the best experts on this subject based on the ideXlab platform.
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sorbitol production from Lactose by engineered lactobacillus casei deficient in sorbitol transport system and mannitol 1 phosphate dehydrogenase
Applied Microbiology and Biotechnology, 2010Co-Authors: Reinout De Boeck, Inmaculada Nadal, Vicente Monedero, Gaspar Perezmartinez, Luz Adriana Sarmientorubiano, María J. YebraAbstract:Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the Lactose Operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert Lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of Lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate.
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sorbitol synthesis by an engineered lactobacillus casei strain expressing a sorbitol 6 phosphate dehydrogenase gene within the Lactose Operon
Fems Microbiology Letters, 2005Co-Authors: Lorenzo Nissen, Gaspar Perezmartinez, María J. YebraAbstract:Sorbitol is claimed to have important health-promoting effects and Lactobacillus casei is a lactic acid bacterium relevant as probiotic and used as a cheese starter culture. A sorbitol-producing L. casei strain might therefore be of considerable interest in the food industry. A recombinant strain of L. casei was constructed by the integration of a d-sorbitol-6-phosphate dehydrogenase-encoding gene (gutF) in the chromosomal Lactose Operon (strain BL232). gutF expression in this strain followed the same regulation as that of the lac genes, that is, it was repressed by glucose and induced by Lactose. 13C-nuclear magnetic resonance analysis of supernatants of BL232 resting cells demonstrated that, when pre-grown on Lactose, cells were able to synthesize sorbitol from glucose. Inactivation of the l-lactate dehydrogenase gene in BL232 led to an increase in sorbitol production, suggesting that the engineered route provides an alternative pathway for NAD+ regeneration.
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elements involved in catabolite repression and substrate induction of the Lactose Operon in lactobacillus casei
Journal of Bacteriology, 1999Co-Authors: Maria Jose Gosalbes, Vicente Monedero, Gaspar PerezmartinezAbstract:ABSTRACT In Lactobacillus casei ATCC 393, the chromosomally encoded Lactose Operon, lacTEGF, encodes an antiterminator protein (LacT), Lactose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) elements (LacE and LacF), and a phospho-β-galactosidase. lacT, lacE, andlacF mutant strains were constructed by double crossover. The lacT strain displayed constitutive termination at a ribonucleic antiterminator (RAT) site, whereas lacE andlacF mutants showed an inducer-independent antiterminator activity, as shown analysis of enzyme activity obtained from transcriptional fusions of lac promoter (lacp) and lacpΔRAT with the Escherichia coli gusAgene in the different lac mutants. These results strongly suggest that in vivo under noninducing conditions, the Lactose-specific PTS elements negatively modulate LacT activity. Northern blot analysis detected a 100-nucleotide transcript starting at the transcription start site and ending a consensus RAT sequence and terminator region. In a ccpA mutant, transcription initiation was derepressed but no elongation through the terminator was observed in the presence of glucose and the inducing sugar, Lactose. Full expression oflacTEGF was found only in a man ccpA double mutant, indicating that PTS elements are involved in the CcpA-independent catabolite repression mechanism probably via LacT.
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establishing a model to study the regulation of the Lactose Operon in lactobacillus casei
Fems Microbiology Letters, 1997Co-Authors: Maria Jose Gosalbes, Vicente Monedero, Carlalfred Alpert, Gaspar PerezmartinezAbstract:The chromosomally encoded Lactose-specific phosphoenol pyruvate-dependent phosphotransferase system (PTS) has been investigated in Lactobacillus casei ATCC 393 [pLZ15-] and it was considered an excellent system to study the regulation of the Lactose Operon. This chromosomal Operon has been cloned and sequenced, being 99% homologous to that encoded on the plasmid pLZ64. Expression of the Lactose Operon in different mutants of L. casei ATCC 393 [pLZ15−] and primer extension analysis revealed that it is subject to a dual regulation: (i) glucose repression possibly mediated by CcpA and PTS elements, and (ii) induction by Lactose through transcriptional antitermination.
W M De Vos - One of the best experts on this subject based on the ideXlab platform.
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characterization of the lactococcus lactis Lactose Operon promoter contribution of flanking sequences and lacr repressor to promoter activity
Journal of Bacteriology, 1992Co-Authors: R J Van Rooijen, Michael J Gasson, W M De VosAbstract:We determined the location, activity, and regulation of the promoter of the Lactococcus lactis 8-kb Lactose Operon (lacABCDFEGX), which encodes the enzymes of the Lactose phosphotransferase system and the tagatose 6-phosphate pathway. The lac promoter sequence corresponds closely to the consensus promoter described for gram-positive bacteria and is located in a back-to-back configuration with the promoter of the divergently transcribed lacR gene, which encodes the LacR repressor. The transcription start sites used under induced (Lactose) and noninduced (glucose) conditions were determined. The minimal promoter region that could be isolated on a single restriction fragment included sequences ranging from -75 to +42. The effect of the presence of flanking sequences and the lacR gene on promoter activity and regulation was studied in Escherichia coli and L. lactis strains by using transcriptional fusions with promoterless chloramphenicol acetyltransferase reporter genes. The results showed that transcriptional regulation of the lac Operon is mediated by the interaction between the LacR repressor, the lac promoter, and sequences in the noncoding region between the lacR and lacA genes. Sequences flanking the minimal promoter region appeared to enhance lac promoter activity much more in L. lactis (5- to 38-fold) than in E. coli (1.3- to 5-fold). Images
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molecular cloning characterization and nucleotide sequence of the tagatose 6 phosphate pathway gene cluster of the Lactose Operon of lactococcus lactis
Journal of Biological Chemistry, 1991Co-Authors: R J Van Rooijen, S Van Schalkwijk, W M De VosAbstract:The tagatose 6-phosphate pathway gene cluster (lacABCD) encoding gaLactose-6-phosphate isomerase, tagatose-6-phosphate kinase, and tagatose-1,6-diphosphate aldolase of Lactococcus lactis subsp. lactis MG1820 has been characterized by cloning, nucleotide sequence analysis, and enzyme assays. Transcription studies showed that the four tagatose 6-phosphate pathway genes are the first genes of the Lactose-inducible Lactose-phosphotransferase Operon consisting of the lacABCDFEGX genes. Using a T7 expression system, it could be shown that the lacA, lacB, lacC, and lacD genes code for proteins with apparent molecular masses of 15, 19, 33, and 36 kDa, respectively. Cell-free extracts of induced and noninduced Escherichia coli cells expressing the lacABCD genes were used to determine the functions of the encoded proteins. Expression of both lacA and lacB was required to obtain gaLactose-6-phosphate isomerase activity. The lacC gene codes for tagatose-6-phosphate kinase, the deduced amino sequence of which is similar to that of E. coli Pfk-2 phosphofructokinase, and Staphylococcus aureus LacC protein. The tagatose-1,6-diphosphate aldolase is encoded by the lacD gene, and its deduced primary sequence, which is homologous to that of the S. aureus LacD protein, predicts an amino acid composition which is virtually identical to that of the previously purified L. lactis E8 tagatose-1,6-diphosphate aldolase.
Vicente Monedero - One of the best experts on this subject based on the ideXlab platform.
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sorbitol production from Lactose by engineered lactobacillus casei deficient in sorbitol transport system and mannitol 1 phosphate dehydrogenase
Applied Microbiology and Biotechnology, 2010Co-Authors: Reinout De Boeck, Inmaculada Nadal, Vicente Monedero, Gaspar Perezmartinez, Luz Adriana Sarmientorubiano, María J. YebraAbstract:Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the Lactose Operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert Lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of Lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate.
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Diacetyl and acetoin production from whey permeate using engineered Lactobacillus casei
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Inmaculada Nadal, Juan Rico, Gaspar Pérez-martínez, María J. Yebra, Vicente MonederoAbstract:The capability of Lactobacillus casei to produce the flavor-related compounds diacetyl and acetoin from whey permeate has been examined by a metabolic engineering approach. An L. casei strain in which the ilvBN genes from Lactococcus lactis, encoding acetohydroxyacid synthase, were expressed from the Lactose Operon was mutated in the lactate dehydrogenase gene (ldh) and in the pdhC gene, which codes for the E2 subunit of the pyruvate dehydrogenase complex. The introduction of these mutations resulted in an increased capacity to synthesize diacetyl/acetoin from Lactose in whey permeate (1,400 mg/l at pH 5.5). The results showed that L. casei can be manipulated to synthesize added-value metabolites from dairy industry by-products.
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elements involved in catabolite repression and substrate induction of the Lactose Operon in lactobacillus casei
Journal of Bacteriology, 1999Co-Authors: Maria Jose Gosalbes, Vicente Monedero, Gaspar PerezmartinezAbstract:ABSTRACT In Lactobacillus casei ATCC 393, the chromosomally encoded Lactose Operon, lacTEGF, encodes an antiterminator protein (LacT), Lactose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) elements (LacE and LacF), and a phospho-β-galactosidase. lacT, lacE, andlacF mutant strains were constructed by double crossover. The lacT strain displayed constitutive termination at a ribonucleic antiterminator (RAT) site, whereas lacE andlacF mutants showed an inducer-independent antiterminator activity, as shown analysis of enzyme activity obtained from transcriptional fusions of lac promoter (lacp) and lacpΔRAT with the Escherichia coli gusAgene in the different lac mutants. These results strongly suggest that in vivo under noninducing conditions, the Lactose-specific PTS elements negatively modulate LacT activity. Northern blot analysis detected a 100-nucleotide transcript starting at the transcription start site and ending a consensus RAT sequence and terminator region. In a ccpA mutant, transcription initiation was derepressed but no elongation through the terminator was observed in the presence of glucose and the inducing sugar, Lactose. Full expression oflacTEGF was found only in a man ccpA double mutant, indicating that PTS elements are involved in the CcpA-independent catabolite repression mechanism probably via LacT.
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establishing a model to study the regulation of the Lactose Operon in lactobacillus casei
Fems Microbiology Letters, 1997Co-Authors: Maria Jose Gosalbes, Vicente Monedero, Carlalfred Alpert, Gaspar PerezmartinezAbstract:The chromosomally encoded Lactose-specific phosphoenol pyruvate-dependent phosphotransferase system (PTS) has been investigated in Lactobacillus casei ATCC 393 [pLZ15-] and it was considered an excellent system to study the regulation of the Lactose Operon. This chromosomal Operon has been cloned and sequenced, being 99% homologous to that encoded on the plasmid pLZ64. Expression of the Lactose Operon in different mutants of L. casei ATCC 393 [pLZ15−] and primer extension analysis revealed that it is subject to a dual regulation: (i) glucose repression possibly mediated by CcpA and PTS elements, and (ii) induction by Lactose through transcriptional antitermination.
