Journal articles: 'Lactate permease'

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Casal, Margarida, Sandra Paiva, Raquel P. Andrade, Carlos Gancedo, and Cecília Leão. "The Lactate-Proton Symport of Saccharomyces cerevisiae Is Encoded by JEN1." Journal of Bacteriology 181, no. 8 (April 15, 1999): 2620–23. http://dx.doi.org/10.1128/jb.181.8.2620-2623.1999.

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ABSTRACT A mutant of Saccharomyces cerevisiae deficient in the lactate-proton symport was isolated. Transformation of the mutant with a yeast genomic library allowed the isolation of the geneJEN1 that restored lactate transport. Disruption ofJEN1 abolished uptake of lactate. The results indicate that, under the experimental conditions tested, no other monocarboxylate permease is able to efficiently transport lactate inS. cerevisiae.

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Stansen, Corinna, Davin Uy, Stephane Delaunay, Lothar Eggeling, Jean-Louis Goergen, and Volker F. Wendisch. "Characterization of a Corynebacterium glutamicum Lactate Utilization Operon Induced during Temperature-Triggered Glutamate Production." Applied and Environmental Microbiology 71, no. 10 (October 2005): 5920–28. http://dx.doi.org/10.1128/aem.71.10.5920-5928.2005.

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ABSTRACT Gene expression changes of glutamate-producing Corynebacterium glutamicum were identified in transcriptome comparisons by DNA microarray analysis. During glutamate production induced by a temperature shift, C. glutamicum strain 2262 showed significantly higher mRNA levels of the NCgl2816 and NCgl2817 genes than its non-glutamate-producing derivative 2262NP. Reverse transcription-PCR analysis showed that the two genes together constitute an operon. NCgl2816 putatively codes for a lactate permease, while NCgl2817 was demonstrated to encode quinone-dependent l-lactate dehydrogenase, which was named LldD. C. glutamicum LldD displayed Michaelis-Menten kinetics for the substrate l-lactate with a Km of about 0.51 mM. The specific activity of LldD was about 10-fold higher during growth on l-lactate or on an l-lactate-glucose mixture than during growth on glucose, d-lactate, or pyruvate, while the specific activity of quinone-dependent d-lactate dehydrogenase differed little with the carbon source. RNA levels of NCgl2816 and lldD were about 18-fold higher during growth on l-lactate than on pyruvate. Disruption of the NCgl2816-lldD operon resulted in loss of the ability to utilize l-lactate as the sole carbon source. Expression of lldD restored l-lactate utilization, indicating that the function of the permease gene NCgl2816 is dispensable, while LldD is essential, for growth of C. glutamicum on l-lactate.

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Exley, Rachel M., Linda Goodwin, Eva Mowe, Jonathan Shaw, Harry Smith, Robert C. Read, and Christoph M. Tang. "Neisseria meningitidis Lactate Permease Is Required for Nasopharyngeal Colonization." Infection and Immunity 73, no. 9 (September 2005): 5762–66. http://dx.doi.org/10.1128/iai.73.9.5762-5766.2005.

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ABSTRACT Neisseria meningitidis is a human specific pathogen that is part of the normal nasopharyngeal flora. Little is known about the metabolic constraints on survival of the meningococcus during colonization of the upper airways. Here we show that glucose and lactate, both carbon energy sources for meningococcal growth, are present in millimolar concentrations within nasopharyngeal tissue. We used a mutant defective for the uptake of lactate (C311ΔlctP) to investigate the contribution of this energy source during colonization. Explants of nasopharyngeal tissue were inoculated with the wild-type strain (C311) and C311ΔlctP; the mutant was recovered at significantly lower levels (P = 0.01) than C311 18 h later. This defect was not due to changes in the expression of adhesins or initial adhesion in C311ΔlctP to epithelial cells. Instead, lactate appears to be important energy source for the bacterium during colonization and is necessary for growth of the bacterium in nasopharyngeal tissue. Studies with other strains defective for the uptake of specific nutrients should provide valuable information about the environment in which N. meningitidis persists during carriage.

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Skory, Christopher D., Ronald E. Hector, Steven W. Gorsich, and Joseph O. Rich. "Analysis of a functional lactate permease in the fungus Rhizopus." Enzyme and Microbial Technology 46, no. 1 (January 2010): 43–50. http://dx.doi.org/10.1016/j.enzmictec.2009.08.014.

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SOARES-SILVA, Isabel, Dorit SCHULLER, Raquel P. ANDRADE, Fátima BALTAZAR, Fernanda CÁSSIO, and Margarida CASAL. "Functional expression of the lactate permease Jen1p of Saccharomyces cerevisiae in Pichia pastoris." Biochemical Journal 376, no. 3 (December 15, 2003): 781–87. http://dx.doi.org/10.1042/bj20031180.

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In Saccharomyces cerevisiae the activity for the lactate–proton symporter is dependent on JEN1 gene expression. Pichia pastoris was transformed with an integrative plasmid containing the JEN1 gene. After 24 h of methanol induction, Northern and Western blotting analyses indicated the expression of JEN1 in the transformants. Lactate permease activity was obtained in P. pastoris cells with a Vmax of 2.1 nmol·s−1·mg of dry weight−1. Reconstitution of the lactate permease activity was achieved by fusing plasma membranes of P. pastoris methanol-induced cells with Escherichia coli liposomes containing cytochrome c oxidase, as proton-motive force. These assays in reconstituted heterologous P. pastoris membrane vesicles demonstrate that S. cerevisiae Jen1p is a functional lactate transporter. Moreover, a S. cerevisiae strain deleted in the JEN1 gene was transformed with a centromeric plasmid containing JEN1 under the control of the glyceraldehyde-3-phosphate dehydrogenase constitutive promotor. Constitutive JEN1 expression and lactic acid uptake were observed in cells grown on either glucose and/or acetic acid. The highest Vmax (0.84 nmol·s−1·mg of dry weight−1) was obtained in acetic acid-grown cells. Thus overexpression of the S. cerevisiae JEN1 gene in both S. cerevisiae and P. pastoris cells resulted in increased activity of lactate transport when compared with the data previously reported in lactic acid-grown cells of native S. cerevisiae strains. Jen1p is the only S. cerevisiae secondary porter characterized so far by heterologous expression in P. pastoris at both the cell and the membrane-vesicle levels.

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PAIVA, Sandra, Arthur L. KRUCKEBERG, and Margarida CASAL. "Utilization of green fluorescent protein as a marker for studying the expression and turnover of the monocarboxylate permease Jen1p of Saccharomyces cerevisiae." Biochemical Journal 363, no. 3 (April 24, 2002): 737–44. http://dx.doi.org/10.1042/bj3630737.

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Green fluorescent protein (GFP) from Aequorea victoria was used as an in vivo reporter protein when fused to the C-terminus of the Jen1 lactate permease of Saccharomyces cerevisiae. The Jen1 protein tagged with GFP is a functional lactate transporter with a cellular abundance of 1670 molecules/cell, and a catalytic-centre activity of 123s−1. It is expressed and tagged to the plasma membrane under induction conditions. The factors involved in proper localization and turnover of Jen1p were revealed by expression of the Jen1p—GFP fusion protein in a set of strains bearing mutations in specific steps of the secretory and endocytic pathways. The chimaeric protein Jen1p—GFP is targeted to the plasma membrane via a Sec6-dependent process; upon treatment with glucose, it is endocytosed via END3 and targeted for degradation in the vacuole. Experiments performed in a Δdoa4 mutant strain showed that ubiquitination is associated with the turnover of the permease.

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Lodi, T., F. Fontanesi, and B. Guiard. "Co-ordinate regulation of lactate metabolism genes in yeast: the role of the lactate permease gene JEN1." Molecular Genetics and Genomics 266, no. 5 (January 2002): 838–47. http://dx.doi.org/10.1007/s00438-001-0604-y.

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Andrade, Raquel P., and Margarida Casal. "Expression of the Lactate Permease Gene JEN1 from the Yeast Saccharomyces cerevisiae." Fungal Genetics and Biology 32, no. 2 (March 2001): 105–11. http://dx.doi.org/10.1006/fgbi.2001.1254.

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9

Ayala, Julio C., and William M. Shafer. "Transcriptional regulation of a gonococcal gene encoding a virulence factor (L-lactate permease)." PLOS Pathogens 15, no. 12 (December 20, 2019): e1008233. http://dx.doi.org/10.1371/journal.ppat.1008233.

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Exley, Rachel M., Hong Wu, Jonathan Shaw, Muriel C. Schneider, Harry Smith, Ann E. Jerse, and Christoph M. Tang. "Lactate Acquisition Promotes Successful Colonization of the Murine Genital Tract by Neisseria gonorrhoeae." Infection and Immunity 75, no. 3 (December 11, 2006): 1318–24. http://dx.doi.org/10.1128/iai.01530-06.

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ABSTRACT Previous studies on Neisseria gonorrhoeae have demonstrated that metabolism of lactate in the presence of glucose increases the growth rate of the bacterium and enhances its resistance to complement-mediated killing. Although these findings in vitro suggest that the acquisition of lactate promotes gonococcal colonization, the significance of this carbon source to the survival of the gonococcus in vivo remains unknown. To investigate the importance of lactate utilization during Neisseria gonorrhoeae genital tract infection, we identified the gene lctP, which encodes the gonococcal lactate permease. A mutant that lacks a functional copy of lctP was unable to take up exogenous lactate and did not grow in defined medium with lactate as the sole carbon source, in contrast to the wild-type and complemented strains; the mutant strain exhibited no growth defect in defined medium containing glucose. In defined medium containing physiological concentrations of lactate and glucose, the lctP mutant demonstrated reduced early growth and increased sensitivity to complement-mediated killing compared with the wild-type strain; the enhanced susceptibility to complement was associated with a reduction in lipopolysaccharide sialylation of the lctP mutant. The importance of lactate utilization during colonization was evaluated in the murine model of lower genital tract infection. The lctP mutant was significantly attenuated in its ability to colonize and survive in the genital tract, while the complemented mutant exhibited no defect for colonization. Lactate is a micronutrient in the genital tract that contributes to the survival of the gonococcus.

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Hosie, A. H. F., D. Allaway, and P. S. Poole. "A Monocarboxylate Permease of Rhizobium leguminosarum Is the First Member of a New Subfamily of Transporters." Journal of Bacteriology 184, no. 19 (October 1, 2002): 5436–48. http://dx.doi.org/10.1128/jb.184.19.5436-5448.2002.

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ABSTRACT Amino acid transport by Rhizobium leguminosarum is dominated by two ABC transporters, the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra). However, mutation of these transporters does not prevent this organism from utilizing alanine for growth. An R. leguminosarum permease (MctP) has been identified which is required for optimal growth on alanine as a sole carbon and nitrogen source. Characterization of MctP confirmed that it transports alanine (Km = 0.56 mM) and other monocarboxylates such as lactate and pyruvate (Km = 4.4 and 3.8 μM, respectively). Uptake inhibition studies indicate that propionate, butyrate, α-hydroxybutyrate, and acetate are also transported by MctP, with the apparent affinity for solutes demonstrating a preference for C3-monocarboxylates. MctP has significant sequence similarity to members of the sodium/solute symporter family. However, sequence comparisons suggest that it is the first characterized permease of a new subfamily of transporters. While transport via MctP was inhibited by CCCP, it was not apparently affected by the concentration of sodium. In contrast, glutamate uptake in R. leguminosarum by the Escherichia coli GltS system did require sodium, which suggests that MctP may be proton coupled. Uncharacterized members of this new subfamily have been identified in a broad taxonomic range of species, including proteobacteria of the β-subdivision, gram-positive bacteria, and archaea. A two-component sensor-regulator (MctSR), encoded by genes adjacent to mctP, is required for activation of mctP expression.

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Chiu, Kuo-Chin, Chen-Jyun Lin, and Gwo-Chyuan Shaw. "Transcriptional regulation of the l-lactate permease gene lutP by the LutR repressor of Bacillus subtilis RO-NN-1." Microbiology 160, no. 10 (October 1, 2014): 2178–89. http://dx.doi.org/10.1099/mic.0.079806-0.

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The Bacillus subtilis lutABC operon encodes three iron–sulfur-containing proteins required for l-lactate utilization and involved in biofilm formation. The transcriptional regulator LutR of the GntR family negatively controls lutABC expression. The lutP gene, which is situated immediately upstream of lutR, encodes an l-lactate permease. Here, we show that lutP expression can be strongly induced by l-lactate and is subject to partial catabolite repression by glucose. Disruption of the lutR gene led to a strong derepression of lutP and no further induction by l-lactate, suggesting that the LutR repressor can also negatively control lutP expression. Electrophoretic mobility shift assay revealed a LutR-binding site located downstream of the promoter of lutA or lutP and containing a consensus inverted repeat sequence 5′-TCATC-N1-GATGA-3′. Reporter gene analysis showed that deletion of each LutR-binding site caused a strong derepression of lutA or lutP. These results indicated that these two LutR-binding sites can function as operators in vivo. Moreover, deletion analysis identified a DNA segment upstream of the lutP promoter to be important for lutP expression. In contrast to the truncated LutR of laboratory strains 168 and PY79, the full-length LutR of the undomesticated strain RO-NN-1, and probably many other B. subtilis strains, can directly and negatively regulate lutP transcription. The absence or presence of the N-terminal 21 aa of the full-length LutR, which encompass a small part of the predicted winged helix–turn–helix DNA-binding motif, may probably alter the DNA-binding specificity or affinity of LutR.

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Nawawi, Roslina A., Justice C. F. Baiano, E. Charlotte E. Kvennefors, and Andrew C. Barnes. "Host-Directed Evolution of a Novel Lactate Oxidase in Streptococcus iniae Isolates from Barramundi (Lates calcarifer)." Applied and Environmental Microbiology 75, no. 9 (March 6, 2009): 2908–19. http://dx.doi.org/10.1128/aem.02147-08.

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ABSTRACT In Streptococcus iniae, lactate metabolism is dependent upon two proteins, lactate permease that mediates uptake and lactate oxidase, a flavin mononucleotide-dependent enzyme that catalyzes oxidation of α-hydroxyacids. A novel variant of the lactate oxidase gene, lctO, in Australian isolates of S. iniae from diseased barramundi was found during a diagnostic screen using LOX-1 and LOX-2 primers, yielding amplicons of 920 bp instead of the expected 869 bp. Sequencing of the novel gene variant (type 2) revealed a 51-nucleotide insertion in lctO, resulting in a 17-amino-acid repeat in the gene product, and three-dimensional modeling indicated formation of an extra loop in the monomeric protein structure. The activities of the lactate oxidase enzyme variants expressed in Escherichia coli were examined, indicating that the higher-molecular-weight type 2 enzyme exhibited higher activity. Growth rates of S. iniae expressing the novel type 2 enzyme were not reduced at lactate concentrations of 0.3% and 0.5%, whereas a strain expressing the type 1 enzyme exhibited reduced growth rates at these lactate concentrations. During a retrospective screen of 105 isolates of S. iniae from Australia, the United States, Canada, Israel, Réunion Island, and Thailand, the type 2 variant arose only in isolates from a single marine farm with unusually high tidal flow in the Northern Territory, Australia. Elevated plasma lactate levels in the fish, resulting from the effort of swimming in tidal flows of up to 3 knots, may exert sufficient selective pressure to maintain the novel, high-molecular-weight enzyme variant.

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Lodi, Tiziana, Michele Saliola, Claudia Donnini, and Paola Goffrini. "Three Target Genes for the Transcriptional Activator Cat8p of Kluyveromyces lactis: Acetyl Coenzyme A Synthetase Genes KlACS1 and KlACS2 and Lactate Permease Gene KlJEN1." Journal of Bacteriology 183, no. 18 (September 15, 2001): 5257–61. http://dx.doi.org/10.1128/jb.183.18.5257-5261.2001.

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ABSTRACT The aerobic yeast Kluyveromyces lactis and the predominantly fermentative Saccharomyces cerevisiaeshare many of the genes encoding the enzymes of carbon and energy metabolism. The physiological features that distinguish the two yeasts appear to result essentially from different organization of regulatory circuits, in particular glucose repression and gluconeogenesis. We have isolated the KlCAT8 gene (a homologue of S. cerevisiae CAT8, encoding a DNA binding protein) as a multicopy suppressor of a fog1 mutation. The Fog1 protein is a homologue of the Snf1 complex components Gal83p, Sip1p, and Sip2p ofS. cerevisiae. While CAT8 controls the key enzymes of gluconeogenesis in S. cerevisiae,KlCAT8 of K. lactis does not (I. Georis, J. J. Krijger, K. D. Breunig, and J. Vandenhaute, Mol. Gen. Genet. 264:193–203, 2000). We therefore examined possible targets of KlCat8p. We found that the acetyl coenzyme A synthetase genes,KlACS1 and KlACS2, were specifically regulated by KlCAT8, but very differently from theS. cerevisiae counterparts. KlACS1 was induced by acetate and lactate, while KlACS2 was induced by ethanol, both under the control of KlCAT8. Also,KlJEN1, encoding the lactate-inducible and glucose-repressible lactate permease, was found under a tight control of KlCAT8.

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Exley, Rachel M., Jonathan Shaw, Eva Mowe, Yao-hui Sun, Nicholas P. West, Michael Williamson, Marina Botto, Harry Smith, and Christoph M. Tang. "Available carbon source influences the resistance of Neisseria meningitidis against complement." Journal of Experimental Medicine 201, no. 10 (May 16, 2005): 1637–45. http://dx.doi.org/10.1084/jem.20041548.

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Neisseria meningitidis is an important cause of septicaemia and meningitis. To cause disease, the bacterium must acquire essential nutrients for replication in the systemic circulation, while avoiding exclusion by host innate immunity. Here we show that the utilization of carbon sources by N. meningitidis determines its ability to withstand complement-mediated lysis, through the intimate relationship between metabolism and virulence in the bacterium. The gene encoding the lactate permease, lctP, was identified and disrupted. The lctP mutant had a reduced growth rate in cerebrospinal fluid compared with the wild type, and was attenuated during bloodstream infection through loss of resistance against complement-mediated killing. The link between lactate and complement was demonstrated by the restoration of virulence of the lctP mutant in complement (C3−/−)-deficient animals. The underlying mechanism for attenuation is mediated through the sialic acid biosynthesis pathway, which is directly connected to central carbon metabolism. The findings highlight the intimate relationship between bacterial physiology and resistance to innate immune killing in the meningococcus.

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Núñez, M. Felisa, M. Teresa Pellicer, Josefa Badı́a, Juan Aguilar, and Laura Baldomà. "The gene yghK linked to the glc operon of Escherichia coli encodes a permease for glycolate that is structurally and functionally similar to L-lactate permease." Microbiology 147, no. 4 (April 1, 2001): 1069–77. http://dx.doi.org/10.1099/00221287-147-4-1069.

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Cruz Ramos, Hugo, Tamara Hoffmann, Marco Marino, Hafed Nedjari, Elena Presecan-Siedel, Oliver Dreesen, Philippe Glaser, and Dieter Jahn. "Fermentative Metabolism of Bacillus subtilis: Physiology and Regulation of Gene Expression." Journal of Bacteriology 182, no. 11 (June 1, 2000): 3072–80. http://dx.doi.org/10.1128/jb.182.11.3072-3080.2000.

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ABSTRACT Bacillus subtilis grows in the absence of oxygen using nitrate ammonification and various fermentation processes. Lactate, acetate, and 2,3-butanediol were identified in the growth medium as the major anaerobic fermentation products by using high-performance liquid chromatography. Lactate formation was found to be dependent on the lctEP locus, encoding lactate dehydrogenase and a putative lactate permease. Mutation of lctE results in drastically reduced anaerobic growth independent of the presence of alternative electron acceptors, indicating the importance of NADH reoxidation by lactate dehydrogenase for the overall anaerobic energy metabolism. Anaerobic formation of 2,3-butanediol via acetoin involves acetolactate synthase and decarboxylase encoded by the alsSD operon. Mutation ofalsSD has no significant effect on anaerobic growth. Anaerobic acetate synthesis from acetyl coenzyme A requires phosphotransacetylase encoded by pta. Similar to the case for lctEP, mutation of pta significantly reduces anaerobic fermentative and respiratory growth. The expression of both lctEP and alsSD is strongly induced under anaerobic conditions. Anaerobic lctEP andalsSD induction was found to be partially dependent on the gene encoding the redox regulator Fnr. The observed fnrdependence might be the result of Fnr-induced arfM(ywiD) transcription and subsequent lctEP andalsSD activation by the regulator ArfM (YwiD). The two-component regulatory system encoded by resDE is also involved in anaerobic lctEP induction. No directresDE influence on the redox regulation ofalsSD was observed. The alternative electron acceptor nitrate represses anaerobic lctEP andalsSD transcription. Nitrate repression requiresresDE- and fnr-dependent expression ofnarGHJI, encoding respiratory nitrate reductase. The genealsR, encoding a regulator potentially responding to changes of the intracellular pH and to acetate, is essential for anaerobic lctEP and alsSD expression. In agreement with its known aerobic function, no obvious oxygen- or nitrate-dependent pta regulation was observed. A model for the regulation of the anaerobic fermentation genes in B. subtilis is proposed.

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Torres‐Corral, Yolanda, and Ysabel Santos. "Development of a real‐time PCR assay for detection and quantification of Streptococcus iniae using the lactate permease gene." Journal of Fish Diseases 44, no. 1 (September 21, 2020): 53–61. http://dx.doi.org/10.1111/jfd.13267.

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Bojunga, N., and K. D. Entian. "Cat8p, the activator of gluconeogenic genes in Saccharomyces cerevisiae, regulates carbon source-dependent expression of NADP-dependent cytosolic isocitrate dehydrogenase (Idp2p) and lactate permease (Jen1p)." Molecular and General Genetics MGG 262, no. 4-5 (December 1999): 869–75. http://dx.doi.org/10.1007/s004380051152.

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Siezen, Roland J., Bernadet Renckens, Iris van Swam, Sander Peters, Richard van Kranenburg, Michiel Kleerebezem, and Willem M. de Vos. "Complete Sequences of Four Plasmids of Lactococcus lactis subsp. cremoris SK11 Reveal Extensive Adaptation to the Dairy Environment." Applied and Environmental Microbiology 71, no. 12 (December 2005): 8371–82. http://dx.doi.org/10.1128/aem.71.12.8371-8382.2005.

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ABSTRACT Lactococcus lactis strains are known to carry plasmids encoding industrially important traits. L. lactis subsp. cremoris SK11 is widely used by the dairy industry in cheese making. Its complete plasmid complement was sequenced and found to contain the plasmids pSK11A (10,372 bp), pSK11B (13,332 bp), pSK11L (47,165 bp), and pSK11P (75,814 bp). Six highly homologous repB-containing replicons were found, all belonging to the family of lactococcal theta-type replicons. Twenty-three complete insertion sequence elements segment the plasmids into numerous modules, many of which can be identified as functional units or containing functionally related genes. Plasmid-encoded functions previously known to reside on L. lactis SK11 plasmids were now mapped in detail, e.g., lactose utilization (lacR-lacABCDFEGX), the proteolytic system (prtM-prtP, pepO, pepF), and the oligopeptide permease system (oppDFBCA). Newly identified plasmid-encoded functions could facilitate the uptake of various cations, while the pabA and pabB genes could be essential for folate biosynthesis. A competitive advantage could be obtained by using the putative flavin adenine dinucleotide-dependent d-lactate dehydrogenase and oxalate:formate antiporter for enhanced ATP synthesis, while the activity of the predicted α-acetolactate decarboxylase may contribute to the formation of an additional electron sink. Various stress response proteins are plasmid encoded, which could enhance strain robustness. A substantial number of these “adaptation” genes have not been described before on L. lactis plasmids. Moreover, several genes were identified for the first time in L. lactis, possibly reflecting horizontal gene transfer.

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González-Rodríguez, Irene, Paula Gaspar, Borja Sánchez, Miguel Gueimonde, Abelardo Margolles, and Ana Rute Neves. "Catabolism of Glucose and Lactose in Bifidobacterium animalis subsp. lactis, Studied by13C Nuclear Magnetic Resonance." Applied and Environmental Microbiology 79, no. 24 (September 27, 2013): 7628–38. http://dx.doi.org/10.1128/aem.02529-13.

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ABSTRACTBifidobacteria are widely used as probiotics in several commercial products; however, to date there is little knowledge about their carbohydrate metabolic pathways. In this work, we studied the metabolism of glucose and lactose in the widely used probiotic strainBifidobacterium animalissubsp.lactisBB-12 byin vivo13C nuclear magnetic resonance (NMR) spectroscopy. The metabolism of [1-13C]glucose was characterized in cells grown in glucose as the sole carbon source. Moreover, the metabolism of lactose specifically labeled with13C on carbon 1 of the glucose or the galactose moiety was determined in suspensions of cells grown in lactose. These experiments allowed the quantification of some intermediate and end products of the metabolic pathways, as well as determination of the consumption rate of carbon sources. Additionally, the labeling patterns in metabolites derived from the metabolism of glucose specifically labeled with13C on carbon 1, 2, or 3 in cells grown in glucose or lactose specifically labeled in carbon 1 of the glucose moiety ([1-13Cglucose]lactose), lactose specifically labeled in carbon 1 of the galactose moiety ([1-13Cgalactose]lactose), and [1-13C]glucose in lactose-grown cells were determined in cell extracts by13C NMR. The NMR analysis showed that the recovery of carbon was fully compatible with the fructose 6-phosphate, or bifid, shunt. The activity of lactate dehydrogenase, acetate kinase, fructose 6-phosphate phosphoketolase, and pyruvate formate lyase differed significantly between glucose and lactose cultures. The transcriptional analysis of several putative glucose and lactose transporters showed a significant induction of Balat_0475 in the presence of lactose, suggesting a role for this protein as a lactose permease. This report provides the firstin vivoexperimental evidence of the metabolic flux distribution in the catabolic pathway of glucose and lactose in bifidobacteria and shows that the bifid shunt is the only pathway involved in energy recruitment from these two sugars. On the basis of our experimental results, a model of sugar metabolism inB. animalissubsp.lactisis proposed.

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González Díaz, Elena, Sonia Álvarez-García, Susana Luque, and José R. Álvarez. "Low-Temperature Hydrophilic Pervaporation of Lactic Acid Esterification Reaction Media." Membranes 12, no. 1 (January 17, 2022): 96. http://dx.doi.org/10.3390/membranes12010096.

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Esterification reactions show a limited conversion due to the presence of water, which favors the opposite reaction. The removal of water from the reaction mixture increases the production of the ester. Pervaporation is an effective dehydration technique, usually applied to binary mixtures. The effect on pervaporation of a reactive multicomponent system involving water, ethanol, ethyl lactate and lactic acid with high acid concentration (13.5 wt. %) at relatively low temperatures (40–80 °C) was studied. Three hydrophilic membranes mainly fabricated for dehydration purposes from Sulzer Chemtech were used, i.e., PERVAP™ 3100, PERVAP™ 2216 and PERVAP™ 1131. The last one revealed as the most suitable for the application and it was further characterized with binary and ternary solutions. The membrane showed high affinity for the lactic acid. The acid permeation played a key role in the water/ethanol and water/ethyl lactate selectivity. Lactic acid permeates and crystalizes in the permeate side of the membrane at very low water concentration (below 2 wt. %), causing a drop in flux and membrane selectivity. Ethyl lactate is responsible of the loss of integrity of the membranes.

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Majore, Kristine, and Inga Ciprovica. "Sensory Assessment of Bi-Enzymatic-Treated Glucose-Galactose Syrup." Fermentation 9, no. 2 (January 31, 2023): 136. http://dx.doi.org/10.3390/fermentation9020136.

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There are a variety of ways to make glucose-galactose syrup (GGS) and other products of lactose hydrolysis; therefore, research is still ongoing and will undoubtedly result in improved methods and lower costs. The aim of the study was to use a two-stage fermentation approach to increase the sweetness of glucose-galactose syrup. Comparing lactose hydrolysis with β-galactosidases, the enzyme Ha-Lactase 5200 (K. lactis) showed the highest hydrolysis yield but NOLA™ Fit5500 (B. licheniformis) and GODO-YNL2 (K. lactis) hydrolysis yields varied. After the two-stage fermentation, the syrups from sweet whey permeate had shown the highest sweet taste intensity scores; the sweetest samples were 1NFS and 1HLS with a score of 9.2 and 9.3, respectively. The presence of fructose in the range of 14 ± 3 to 25 ± 1 %, significantly (p < 0.05) increased the sweetness of the syrups. Obtained syrups from whey permeates using enzymes NOLA™ Fit5500 and Ha-Lactase 5200 contained less than 10% lactose. Additionally, results indicate that hydrolysis of lactose and subsequent enhancement of sweetness through glucose isomerisation may provide additional benefits through the production of galacto-oligosaccharides (GOS) in the range of 2 ± 1 to 34 ± 7%.

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Rosenberg, S. O., T. Fadil, and V. L. Schuster. "A basolateral lactate/H+ co-transporter in Madin-Darby Canine Kidney (MDCK) cells." Biochemical Journal 289, no. 1 (January 1, 1993): 263–68. http://dx.doi.org/10.1042/bj2890263.

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Monolayers of Madin-Darby Canine Kidney (MDCK) cells grown on permeable filters generated lactate aerobically and accumulated it preferentially in the basolateral compartment, suggesting the presence of a lactate carrier. The mechanism of lactate transport across apical and basolateral membranes was examined by determining intracellular pH (pHi) microspectrofluorimetrically after addition of lactate to the extracellular solutions and by measuring uptake of [14C]lactate. Addition of 20 mM lactate to the apical compartment produced no change in pHi, whereas lactate added to the basolateral compartment rapidly and reversibly lowered pHi. Pyruvate produced similar results. Inhibitors of lactate/H+ co-transporters, alpha-cyano-4-hydroxycinnamate (CnCN) and quercetin, partially inhibited the fall in pHi produced by basolateral lactate. In contrast, the disulphonic stilbene. DIDS (4,4′-di-isothiocyanostilbene-2,2′-disulphonic acid) produced no inhibition at 0.5 mM. Kinetic analysis was performed by applying basolateral lactate at various concentrations and measuring the rate of entry (delta pHi/min) in the presence and absence of CnCN. Lactate flux was shown to occur by both non-ionic diffusion and a alpha-cyano-4-hydroxycinnamate-sensitive component (carrier). The latter has a Km of approximately 7 mM for the lactate anion. Propionate, but not formate, lowered pHi to the same degree as did equimolar lactate, but the propionate effect was not inhibited by CnCN. Influx of [14C]lactate was substantially greater across the basolateral membrane than across the apical membrane and occurred in the absence of Na+. We conclude that MDCK cells grown on permeable filters generate lactate aerobically and transport it across the basolateral membrane by way of a lactate/H+ cotransporter.

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Kai, Hiroyuki, Yuto Kato, Ryoma Toyosato, and Matsuhiko Nishizawa. "Fluid-permeable enzymatic lactate sensors for micro-volume specimen." Analyst 143, no. 22 (2018): 5545–51. http://dx.doi.org/10.1039/c8an00979a.

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Gibello, A., M. D. Collins, L. Domínguez, J. F. Fernández-Garayzábal, and P. T. Richardson. "Cloning and Analysis of the l-Lactate Utilization Genes from Streptococcus iniae." Applied and Environmental Microbiology 65, no. 10 (October 1, 1999): 4346–50. http://dx.doi.org/10.1128/aem.65.10.4346-4350.1999.

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ABSTRACT The presence of lactate oxidase was examined in eightStreptococcus species and some related species of bacteria. A clone (pGR002) was isolated from a genomic library ofStreptococcus iniae generated in Escherichia coli, containing a DNA fragment spanning two genes designatedlctO and lctP. We show that these genes are likely to be involved in the l-lactic acid aerobic metabolism of this organism. This DNA fragment has been sequenced and characterized. A comparison of the deduced amino acid sequence of LctP protein demonstrated that the protein had significant homology with thel-lactate permeases of other bacteria. The amino acid sequence of the LctO protein of S. iniae also showed a strong homology to l-lactate oxidase fromAerococcus viridans and some NAD-independent lactate dehydrogenases, all belonging to the family of flavin mononucleotide-dependent α-hydroxyacid-oxidizing enzymes. Biochemical assays of the gene products confirm the identity of the genes from the isolated DNA fragment and reveal a possible role for the lactate oxidase from S. iniae. This lactate oxidase is discussed in relation to the growth of the organism in response to carbon source availability.

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Boukila, B., J. R. Seoane, J. F. Bernier, J. Goulet, and H. V. Petit. "Effect of feeding fermented, ammoniated, condensed whey permeate on intake, digestibility, rumen fermentation, and acid-base balance in sheep." Canadian Journal of Animal Science 75, no. 1 (March 1, 1995): 135–43. http://dx.doi.org/10.4141/cjas95-018.

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Nine DLS rumen-cannulated wethers (69 kg avg BW) were used to study the effects of dietary supplementation with two types of fermented, ammoniated, condensed whey permeate on performance, rumen physiology and acid-base status in sheep fed high-grain diets. Sheep were fed three isonitrogenous (16% CP) diets according to a triple 3 × 3 Latin square design, with three 21-d periods each. One whey permeate contained ammonium lactate (AL) while the other contained ammonium propionate (AP). Urea was used as a source of NPN in the control diet (C). Diets, offered ad libitum, contained 78% barley and 18% dehydrated alfalfa meal. Dry matter and digestible energy intakes were about 15% higher for diets AL and AP than for diet C (P < 0.05). Dry matter digestibility was not affected by the treatments, whereas organic matter and energy digestibilities tended to be higher for diet AP than for diet AL (P < 0.07). Rumen fermentation was not affected by the treatments. Over a 4-h post-feeding period, sheep fed diet C had higher plasma concentrations of lactate (P < 0.06) and acetate (P < 0.04) but lower levels of plasma propionate (P < 0.06) than sheep fed the AL and AP diets. Plasma propionate 2 h after feeding was higher in sheep fed the AL diet versus the AP diet (P < 0.01). Sheep blood was mildly alkalotic despite the fact that sheep were fed a high-grain diet. The two types of fermented, ammoniated and condensed whey permeate were found to be good sources of NPN. Key words: Whey, rumen fermentation, acid-base balance, sheep

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Matsumoto, Michiaki, Masashi Yamamoto, and Kazuo Kondo. "Use of Bacterial Cellulose from Nata de Coco as Base Polymer for Liquid Membranes Containing Ionic Liquids." Australian Journal of Chemistry 65, no. 11 (2012): 1497. http://dx.doi.org/10.1071/ch12307.

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Bacterial cellulose is becoming a promising biopolymer for membrane separation due to its biocompatibility. We prepared bacterial cellulose membranes from nata de coco, an indigenous dessert of the Philippines, as a support or a base polymer in the liquid membrane process. When we prepared bacterial cellulose membranes in the presence of Aliquat 336 as an ionic liquid, we obtained stable bacterial cellulose membranes. We carried out two different permeation experiments on lactate and organic nitrogen compounds. In the case of lactate permeation, the lactate remained in the membrane phase due to the strong interaction between the cellulose and the lactate by hydrogen bonding. For organic nitrogen compounds without strong hydrogen bonding moieties, quinoline and pyridine successfully permeated through the membranes. Higher selectivity against heptane was observed than previously reported results. The bacterial membranes from nata de coco containing Aliquat 336 were found to be promising for the separation of organic nitrogen compounds.

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Amrane, Abdeltif. "Effect of inorganic phosphate on lactate production byLactobacillus helveticus grown on supplemented whey permeate." Journal of Chemical Technology & Biotechnology 75, no. 3 (March 2000): 223–28. http://dx.doi.org/10.1002/(sici)1097-4660(200003)75:3<223::aid-jctb205>3.0.co;2-5.

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Prem, Caroline, and Bernd Pelster. "Swimbladder gas gland cells cultured on permeable supports regain their characteristic polarity." Journal of Experimental Biology 204, no. 23 (December 1, 2001): 4023–29. http://dx.doi.org/10.1242/jeb.204.23.4023.

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SUMMARY A cell culture system has been developed in which swimbladder gas gland cells from the European eel (Anguilla anguilla) were cultured on a permeable support. Cells seeded on Anodisc 13 (Whatman) or Costar Transwell 13 mm membranes form a confluent cell layer within the first 2 or 3 days of culture but, on the basis of measurements of transepithelial resistance, it is a ‘leaky’ cell layer. In a superfusion system, the apical and basal sides of the cells were superfused asymmetrically, with saline on the apical side and a glucose-containing cell culture medium on the basal side. Under these conditions, the cells continuously produced lactic acid, and approximately 60–70 % of this lactate was released at the basal side. To mimic the in vivo situation, the saline solution supplied to the apical side was replaced by humidified air in an additional series of experiments. Cells cultured in an air/liquid system produced even more lactate, and this lactate was only released to the basal side; there was no leakage of fluid to the apical side. After 4 or 5 days in the superfusion system, the cells were fixed for histological examination. The cells were columnar, similar to gas gland cells in vivo, and showed a clear polarity, with some small microvilli at the apical membrane and extensive membrane foldings at lateral and basal membranes. Immunohistochemical localization of Na+/K+-ATPase revealed that this ATPase was present mainly in the lateral membranes; it was never found in the apical membranes. Cells cultured in the air/liquid system showed a similar structure and polarity.

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Caballero, Alejandro, Pablo Caballero, Federico León, Bruno Rodríguez-Morgado, Luis Martín, Juan Parrado, Jenifer Vaswani, and Alejandro Ramos-Martín. "Conversion of Whey into Value-Added Products through Fermentation and Membrane Fractionation." Water 13, no. 12 (June 9, 2021): 1623. http://dx.doi.org/10.3390/w13121623.

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The cheese whey (95% composed of water) is an effluent produced in the cheese industry, of which more than 1.5 million tons are generated in Spain, constituting a serious environmental problem. The process starts with a new fermentative/enzymatic technology that totally converts whey, mainly composed by lactose, proteins, and salts, into a fermented product with higher added value. This new product is mainly composed by lactic acid bacteria biomass, ammonium lactate, and a protein hydrolysate. To separate valuable fractions, this fermented product is processed by a two-stage membrane system, which is a very innovative process in this type of fermented product. The first stage consists of ultrafiltration to separate all suspended solids. As a result of this stage, a product mainly constituted by lactic acid bacteria that have both agronomic applications, mainly as a biocontrol and biofertilizer/bio-stimulant, and applications in animal feeding as a probiotic, is obtained. The second stage consists of reverse osmosis used to concentrate the ultrafiltered permeate obtained earlier, leading to a microbiologically stable product and reducing transport costs. The concentrate is mainly composed of ammonium lactate and a protein hydrolysate, constituted by peptides and free amino acids, which has application both in agriculture as a bio-stimulant and in animal feeding, and the permeate is water, reusable in other industrial processes. This work demonstrates the technical feasibility of this valorization process to achieve the objective of “Waste 0” from a problematic by-product, while obtaining products with commercial utility.

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Majore, Kristine, and Inga Ciprovica. "Bioconversion of Lactose into Glucose–Galactose Syrup by Two-Stage Enzymatic Hydrolysis." Foods 11, no. 3 (January 30, 2022): 400. http://dx.doi.org/10.3390/foods11030400.

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Fermentation technology enables the better use of resources and the conversion of dairy waste into valuable food products. The aim of this study is to evaluate the conversion rate of glucose into fructose by immobilised glucose isomerase (GI) in sweet and acid whey permeates for glucose–galactose syrup production. The experiments demonstrated that the highest concentration of glucose and galacto-oligosaccharides (GOSs) in sweet and acid whey permeates was reached by GODO-YNL2 β-galactosidase, 32 ± 2% and 28 ± 1%, respectively. After glucose isomerisation, the highest fructose yield was 23 ± 0.3% and 13 ± 0.4% in sweet and acid whey permeates, where Ha-Lactase 5200 β-galactosidase was used for lactose hydrolysis in sweet and acid whey permeates. Finally, the results of this study highlight the potential for two-stage enzymatic hydrolysis to increase the sweetness of glucose–galactose syrup made from sweet and acid whey permeates.

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Bunthof, Christine J., Saskia van Schalkwijk, Wilco Meijer, Tjakko Abee, and Jeroen Hugenholtz. "Fluorescent Method for Monitoring Cheese Starter Permeabilization and Lysis." Applied and Environmental Microbiology 67, no. 9 (September 1, 2001): 4264–71. http://dx.doi.org/10.1128/aem.67.9.4264-4271.2001.

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ABSTRACT A fluorescence method to monitor lysis of cheese starter bacteria using dual staining with the LIVE/DEAD BacLight bacterial viability kit is described. This kit combines membrane-permeant green fluorescent nucleic acid dye SYTO 9 and membrane-impermeant red fluorescent nucleic acid dye propidium iodide (PI), staining damaged membrane cells fluorescent red and intact cells fluorescent green. For evaluation of the fluorescence method, cells of Lactococcus lactis MG1363 were incubated under different conditions and subsequently labeled with SYTO 9 and PI and analyzed by flow cytometry and epifluorescence microscopy. Lysis was induced by treatment with cell wall-hydrolyzing enzyme mutanolysin. Cheese conditions were mimicked by incubating cells in a buffer with high protein, potassium, and magnesium, which stabilizes the cells. Under nonstabilizing conditions a high concentration of mutanolysin caused complete disruption of the cells. This resulted in a decrease in the total number of cells and release of cytoplasmic enzyme lactate dehydrogenase. In the stabilizing buffer, mutanolysin caused membrane damage as well but the cells disintegrated at a much lower rate. Stabilizing buffer supported permeabilized cells, as indicated by a high number of PI-labeled cells. In addition, permeable cells did not release intracellular aminopeptidase N, but increased enzyme activity was observed with the externally added and nonpermeable peptide substrate lysyl-p-nitroanilide. Finally, with these stains and confocal scanning laser microscopy the permeabilization of starter cells in cheese could be analyzed.

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Chiu, C. P., and F. V. Kosikowski. "Conversion of Glucose in Lactase-Hydrolyzed Whey Permeate to Fructose with Immobilized Glucose Isomerase." Journal of Dairy Science 69, no. 4 (April 1986): 959–64. http://dx.doi.org/10.3168/jds.s0022-0302(86)80488-x.

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Jang, Ki Beom, Jerry M. Purvis, and Sung Woo Kim. "143 Supplemental effects of whey permeate on growth performance and gut health of nursery pigs." Journal of Animal Science 97, Supplement_2 (July 2019): 81–82. http://dx.doi.org/10.1093/jas/skz122.148.

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Abstract Lactose or milk oligosaccharides in milk products may enhance gut health and thus growth of nursery pigs. This study aimed to evaluate supplemental effects of increasing levels of whey permeate on growth performance and gut health in nursery pigs during 7 to 11 kg BW. 1,200 pigs at 7.5 kg BW were allotted to 6 treatments based on a randomized complete block design using BW of pen as blocks. Treatment diets were formulated to meet NRC nutrient requirements with 6 levels of whey permeate (0, 3.75, 7.50, 11.25, 15.00, and 18.75%) and fed to pigs for 11 d. Feed intake and BW were measured during 11 d, and 1 pig per pen were euthanized to collect the jejunum to evaluate TNF-α, IL-8, morphology, digestive enzyme activity, crypt cell proliferation rate, and microbiota. Data were analyzed using contrasts in the MIXED procedure and a broken-line analysis in NLIN procedure of SAS. Increasing whey permeate linearly increased (P < 0.05) ADG (349 to 414 g/d) and G:F (0.783 to 0.851), tended to linearly increase (P = 0.062) ADFI (442 to 484 g/d), linearly increased (P < 0.05) crypt cell proliferation rate (27.8 to 37.0%), linearly decreased (P < 0.05) lactase activity (15.84 to 6.60 U/mg), and tended to linearly decrease (P = 0.082) crypt depth (268 to 251 μm). Using a broken line analysis, the optimum supplementation level of whey permeate was 13.60% for G:F. Supplementation of whey permeate increased (P < 0.05) IL-8 (170 to 209 pg/mg) and decreased (P < 0.05) Firmicutes to Bacteroidetes ratio (6.24 to 3.24) in the jejunum. In conclusion, supplementation of whey permeate enhanced growth performance and also positively affected gut health by modulating inflammatory response and microbiota in the jejunum of nursery pigs from 7 to 11 kg BW.

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Paredes Valencia, Adriana, Alain Doyen, Scott Benoit, Manuele Margni, and Yves Pouliot. "Effect of Ultrafiltration of Milk Prior to Fermentation on Mass Balance and Process Efficiency in Greek-Style Yogurt Manufacture." Foods 7, no. 9 (September 4, 2018): 144. http://dx.doi.org/10.3390/foods7090144.

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Ultrafiltration (UF) can be used to concentrate yogurt to produce Greek-style yogurt (GSY) (UF-YOG), but this generates acid whey permeate, which is an environmental issue. However, when UF is applied before fermentation (UF-MILK), a nonacidified whey permeate is generated. For this study, two model GSYs (UF-YOG and UF-MILK) were produced to compare the composition, UF performance, and energy consumption of the two processes. For UF-MILK, skim milk was ultrafiltered with a 30 kDa spiral-wound UF membrane to achieve a 3× volume reduction factor (VRF). The retentate was fermented to a pH of 4.5. The UF-YOG process was the same except that regular yogurt was ultrafiltered. Both GSYs had similar protein (~10%) and solid content (~17%). As expected, lactic acid/lactate was not detected in UF-MILK permeate, while 7.3 g/kg was recovered from the UF-YOG permeate. Permeation flux values (11.6 to 13.3 L m−2 h−1) and total flux decline (47% to 50%) were constant during UF-MILK, whereas drastic decreases in these two membrane performance indicators (average flux: 38.5 to 10.9 L m−2 h−1; total flux decline: 2% to 38%) were calculated for UF-YOG. Moreover, for UF-YOG, UF membrane performance never recovered, even when drastic and repeated cleaning steps were applied. Energy consumption was 1.6 kWh/kg GSY and remained constant for UF-MILK, whereas it increased from 0.6 to 1.5 kWh/kg GSY for UF-YOG. Our results show that, although the composition of GSYs was similar for both processes, the UF step of yogurt concentration affected process efficiency due to drastic and permanent membrane fouling.

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Mihara, Hirotaka, Mai Kugawa, Kanae Sayo, Fumiya Tao, Marie Shinohara, Masaki Nishikawa, Yasuyuki Sakai, Takeshi Akama, and Nobuhiko Kojima. "Improved Oxygen Supply to Multicellular Spheroids Using A Gas-permeable Plate and Embedded Hydrogel Beads." Cells 8, no. 6 (May 31, 2019): 525. http://dx.doi.org/10.3390/cells8060525.

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Culture systems for three-dimensional tissues, such as multicellular spheroids, are indispensable for high-throughput screening of primary or patient-derived xenograft (PDX)-expanded cancer tissues. Oxygen supply to the center of such spheroids is particularly critical for maintaining cellular functions as well as avoiding the development of a necrotic core. In this study, we evaluated two methods to enhance oxygen supply: (1) using a culture plate with a gas-permeable polydimethylsiloxane (PDMS) membrane on the bottom, and; (2) embedding hydrogel beads in the spheroids. Culturing spheroids on PDMS increased cell growth and affected glucose/lactate metabolism and CYP3A4 mRNA expression and subsequent enzyme activity. The spheroids, comprised of 5000 Hep G2 cells and 5000 20 µm-diameter hydrogel beads, did not develop a necrotic core for nine days when cultured on a gas-permeable sheet. In contrast, central necrosis in spheroids lacking hydrogel beads was observed after day 3 of culture, even when using PDMS. These results indicate that the combination of gas-permeable culture equipment and embedded hydrogel beads improves culture 3D spheroids produced from primary or PDX-expanded tumor cells.

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Drężek, Karolina, Joanna Kozłowska, Anna Detman, and Jolanta Mierzejewska. "Development of a Continuous System for 2-Phenylethanol Bioproduction by Yeast on Whey Permeate-Based Medium." Molecules 26, no. 23 (December 6, 2021): 7388. http://dx.doi.org/10.3390/molecules26237388.

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2-Phenylethanol (2-PE) is an alcohol with a rosy scent and antimicrobial activity, and therefore, it is widely used in the food and cosmetic industries as an aroma and preservative. This work was aimed to draw up a technology for 2-PE bioproduction on whey permeate, which is waste produced by the dairy industry, rich in lactase and proteins. Its composition makes it a harmful waste to dispose of; however, with a properly selected microorganism, it could be converted to a value-added product. Herein, two yeast Kluyveromyces marxianus strains and one Kluyveromyces lactis, isolated from dairy products, were tested for 2-PE production, firstly on standard media and then on whey permeate based media in batch cultures. Thereafter, the 2-PE bioproduction in a continuous system in a 4.8 L bioreactor was developed, and subsequently, the final product was recovered from culture broth. The results showed that the yield of 2-PE production increased by 60% in the continuous culture compared to batch culture. Together with a notable reduction of chemical oxygen demand for whey permeate, the present study reports a complete, effective, and environmentally friendly strategy for 2-PE bioproduction with a space-time yield of 57.5 mg L−1 h−1.

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Norris, S. H., and S. J. Hersey. "Stimulation of pepsinogen secretion in permeable isolated gastric glands." American Journal of Physiology-Gastrointestinal and Liver Physiology 249, no. 3 (September 1, 1985): G408—G415. http://dx.doi.org/10.1152/ajpgi.1985.249.3.g408.

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Rabbit isolated gastric glands were treated with digitonin so that stimulation of pepsinogen secretion could be studied in a permeable system. Criteria for permeabilization were the release of lactate dehydrogenase in response to digitonin as well as the finding that calcium stimulation and spermine inhibition required the presence of digitonin. Other evidence confirmed that digitonin directly permeabilized chief cells. Pepsinogen secretion was elicited from digitonin-treated gastric glands by a number of agents, including calcium, vanadate, cholecystokinin octapeptide (CCK-OP), 8-bromo-adenosine 3',5'-cyclic monophosphate, and forskolin. Spermine was found to inhibit secretion stimulated by each of these agents only in the presence of digitonin, suggesting an intracellular site of spermine action. We concluded that spermine inhibition of secretion could be used as a marker of secretion elicited from permeable chief cells. The ability to stimulate pepsinogen secretion by such agents as CCK-OP and forskolin suggests that stimulus-secretion coupling is virtually intact even in permeable chief cells. We felt that this preparation should offer unusual opportunities for investigating the mechanisms involved in the intracellular regulation and activation of pepsinogen secretion.

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Van Beers, E. H., R. H. Al, E. H. H. M. Rings, A. W. C. Einerhand, J. Dekker, and H. A. Büller. "Lactase and sucrase-isomaltase gene expression during Caco-2 cell differentiation." Biochemical Journal 308, no. 3 (June 15, 1995): 769–75. http://dx.doi.org/10.1042/bj3080769.

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The Caco-2 cell line is derived from a human colon adenocarcinoma and differentiates in vitro into small-intestinal enterocyte-like cells, expressing the hydrolases lactase and sucrase-isomaltase. We cultured Caco-2 cells on permeable supports from 0 to 37 days after plating to study endogenous lactase and sucrase-isomaltase gene expression in relation to cell differentiation. Profiles of lactase and sucrase-isomaltase mRNA, protein and enzyme activity were analysed on a per-cell basis, using immunocytochemistry, RNase protection assays, metabolic polypeptide labelling and enzyme activity assays. Tight-junction formation was complete 6 days after plating. Immunocytochemistry of Caco-2 cross-sections showed lactase and sucrase-isomaltase predominantly in the microvillar membrane of polarized cells. mRNA, protein and enzyme activity of lactase appeared consecutively, reaching maximum levels 8-11 days after plating. Whereas lactase mRNA and protein biosynthesis showed a sharp decline after peak levels, lactase activity remained high until 37 days after plating. In contrast, mRNA and protein biosynthesis and activity of sucrase-isomaltase peaked successively 11-21 days after plating, and exhibited comparable levels throughout the entire experiment. The following conclusions were reached. (1) In Caco-2 cells, biosynthesis of lactase and sucrase-isomaltase is regulated by the amount of their mRNAs, indicating transcriptional control. (2) Sucrase-isomaltase activity is most probably transcriptionally controlled at all time points. (3) In contrast, lactase activity is initially regulated by its level of biosynthesis. After its peak at 8 days, the slow decline in activity compared with its biosynthesis indicates high stability. (4) Different mRNA profiles for lactase and sucrase-isomaltase indicate different mechanisms of transcriptional regulation of these genes.

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Yin, Jianhua, Yiyang Sun, Yinting Mao, Miao Jin, and Haichun Gao. "PBP1a/LpoA but Not PBP1b/LpoB Are Involved in Regulation of the Major β-Lactamase GeneblaAin Shewanella oneidensis." Antimicrobial Agents and Chemotherapy 59, no. 6 (March 30, 2015): 3357–64. http://dx.doi.org/10.1128/aac.04669-14.

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ABSTRACTβ-Lactamase production is one of the most important strategies for Gram-negative bacteria to combat β-lactam antibiotics. Studies of the regulation of β-lactamase expression have largely been focused on the class C β-lactamase AmpC, whose induction by β-lactams requires LysR-type regulator AmpR and permease AmpG-dependent peptidoglycan recycling intermediates. InShewanella, which is ubiquitous in aquatic environments and is a reservoir for antibiotic resistance, production of the class D β-lactamase BlaA confers bacteria with natural resistance to many β-lactams. Expression of theblaAgene in the genus representativeShewanella oneidensisis distinct from the AmpC paradigm because of the lack of an AmpR homologue and the presence of an additional AmpG-independent regulatory pathway. In this study, using transposon mutagenesis, we identify proteins that are involved inblaAregulation. Inactivation ofmrcAandlpoA, which encode penicillin binding protein 1a (PBP1a) and its lipoprotein cofactor, LpoA, respectively, drastically enhancesblaAexpression in the absence of β-lactams. Although PBP1b and its cognate, LpoB, also exist inS. oneidensis, their roles inblaAinduction are dispensable. We further show that themrcA-mediatedblaAexpression is independent of AmpG.

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Khatib-Massalha, Eman, Suditi Bhattacharya, Hassan Massalha, Karin Golan, Orit Kollet, Anju Kumari, Francesca Avemaria, et al. "Acute Inflammation Induces Lactate Release By Bone Marrow Neutrophils That Promotes Their Mobilization Via Endothelial GPR81 Signaling." Blood 134, Supplement_1 (November 13, 2019): 3582. http://dx.doi.org/10.1182/blood-2019-123248.

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Innate immune neutrophils provide the first line of host defense against bacterial infections. Neutrophils under steady state rely almost entirely on glycolysis and exhibit very low levels of oxidative phosphorylation. The metabolite lactate has long been considered a "waste byproduct" of cell metabolism which accumulates during inflammation and sepsis. Increased plasma lactate levels in human patients is used as a marker for sepsis diagnosis. However, the direct effector actions of lactate, particularly in regulating neutrophil mobilization and function during inflammation has remained obscure. To better understand the metabolic consequences of BM neutrophil activation during the onset of inflammation, we tested how bacterial lipopolysaccharides (mimicking gram negative bacterial inflammation) introduced intraperitoneally (i.p.) affect neutrophil metabolism and mobilization. RNAseq of sorted BM neutrophils revealed that LPS-activated neutrophils upregulate enzymes catalyzing the first part of glycolysis (hexokinase and PFKL) and downregulate the expression of TCA cycle enzymatic genes. In addition, LPS enhanced neutrophil lactate production and release as indicated by higher levels of BM lactate and higher expression of LDHA and MCT4. In addition, LPS increased NADPH oxidase (NOX)-mediated reactive oxygen species and HIF-1α levels in BM neutrophils, which are up-stream of glycolytic enzymes and lactate production and release. Recently, we reported that i.p. lactate administration rapidly activated and mobilized neutrophils from BM to the circulation (ASH, 2017). To test if lactate acts preferentially on neutrophils, we also examined other types of hematopoietic cells. Interestingly, we found that lactate specifically and rapidly (i.e., within 4 hrs) mobilized neutrophils to the circulation whereas the levels of peripheral blood (PB) monocytes, lymphocytes, granulocyte monocyte progenitors (GMPs) and hematopoietic progenitor stem cells (LSK) were reduced following lactate administration. LPS treatment failed to mobilize activated ROShigh neutrophils to the PB in NOX-/- mice, while lactate administration partially rescued this defect following LPS treatment. Our data also reveal that the NOX/ROS axis operates upstream of lactate production in BM neutrophils since abnormal metabolic rates were found in NOX-/- neutrophils during the onset of the acute inflammatory responses. Moreover, we found that BM endothelial cells (BMEC) abundantly express the highly selective lactate receptor GPR81, and that neutrophil-released lactate increased BM vascular permeability via BMEC GPR81 signaling (ASH, 2017). Consistent with a role of the lactate/GPR81 axis in enhanced vascular permeability, we find that i.p. injected LPS reduced VE-Cadherin expression on highly permeable sBMECs in GPR81 dependent manner. Notably, neutralizing VE-Cadherin in GPR81-/- mice can rescue and elevate PB neutrophil levels, similarly to wild-type (WT) mice, suggesting that VE-Cadherin is downstream of GPR81 signaling and plays a role in neutrophil mobilization. Finally, to examine the potential clinical relevance of our findings, we infected WT, NOX-/- and GPR81-/- mice with Salmonella Typhimurium and found out that this pathogen drove high generation of ROS, elevated HIF-1αlevels, and triggered lactate production and release in WT BM neutrophils. In contrast, BM neutrophils of infected NOX-/- mice exhibited significantly lower HIF-1αand impaired lactate production and release. Consequently, WT mice infected with Salmonella had a higher levels of neutrophils in the blood, as compared to their NOX-/- or GPR81-/- mice counterparts. Altogether, our data reveal that the same regulatory mechanisms by which neutrophils respond to LPS challenges are used during bacterial infection with Salmonella. Our study highlights lactate released by BM neutrophils as a key pro-inflammatory stimulus of a novel immune-metabolic crosstalk which is triggered by infection and locally opens the BM vascular barrier to facilitate neutrophil mobilization and recruitment to sites of inflammation. Targeting this immune-metabolic crosstalk between lactate-producing neutrophils and the BM endothelium could be useful for the control of pathological neutrophil activation and mobilization during bacterial infections and help treatments of neutrophil related immune disorders. Disclosures No relevant conflicts of interest to declare.

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Duranton, Christophe, Stephan M. Huber, Valerie Tanneur, Verena B. Brand, Canan Akkaya, Ekaterina V. Shumilina, Ciprian D. Sandu, and Florian Lang. "Organic Osmolyte Permeabilities of the Malaria-induced Anion Conductances in Human Erythrocytes." Journal of General Physiology 123, no. 4 (March 29, 2004): 417–26. http://dx.doi.org/10.1085/jgp.200308919.

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Infection of human erythrocytes with the malaria parasite Plasmodium falciparum induces new permeability pathways (NPPs) in the host cell membrane. Isotopic flux measurements demonstrated that the NPP are permeable to a wide variety of molecules, thus allowing uptake of nutrients and release of waste products. Recent patch-clamp recordings demonstrated the infection-induced up-regulation of an inwardly and an outwardly rectifying Cl− conductance. The present experiments have been performed to explore the sensitivity to cell volume and the organic osmolyte permeability of the two conductances. It is shown that the outward rectifier has a high relative lactate permeability (Plactate/PCl = 0.4). Sucrose inhibited the outward-rectifier and abolished the infection-induced hemolysis in isosmotic sorbitol solution but had no or little effect on the inward-rectifier. Furosemide and NPPB blocked the outward-rectifying lactate current and the sorbitol hemolysis with IC50s in the range of 0.1 and 1 μM, respectively. In contrast, the IC50s of NPPB and furosemide for the inward-rectifying current were >10 μM. Osmotic cell-shrinkage inhibited the inwardly but not the outwardly rectifying conductance. In conclusion, the parasite-induced outwardly-rectifying anion conductance allows permeation of lactate and neutral carbohydrates, whereas the inward rectifier seems largely impermeable to organic solutes. All together, these data should help to resolve ongoing controversy regarding the number of unique channels that exist in P. falciparum–infected erythrocytes.

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Fusshoeller, Andreas, Jessica Baehr, Bernd Grabensee, and Joerg Plum. "Biocompatibility of a Bicarbonate/Lactate-Buffered PD Fluid Tested with a Double-Chamber Cell Culture System." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 25, no. 4 (July 2005): 387–93. http://dx.doi.org/10.1177/089686080502500415.

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Objective In peritoneal dialysis (PD), neutrally buffered PD fluids with lower concentrations of glucose degradation products (GDP) have tested superior to conventional fluids in terms of biocompatibility. However, conventional in vitro studies provoke debate because, due to the lack of subsequent equilibration with the blood, they do not resemble the true intraperitoneal situation of PD. Methods We established a double-chamber cell culture system with peritoneal mesothelial cells seeded on top of a permeable membrane, with a physiological buffer below. Thus adequately reflecting the in vivo equilibration pattern, we compared a conventional fluid with a neutral bicarbonate/lactate-buffered PD solution. Using an exchange pattern adapted from an 8-hour continuous ambulatory PD regimen, cell viability was assessed with an MTT assay, and cell function via constitutive and stimulated interleukin (IL)-6 release. As an indicator of potential induction of fibrosis and as a parameter of mesothelial cell integrity, respectively, transforming growth factor-beta 1 (TGF-β1) generation and cancer antigen 125 (CA125) release were measured. Results The conventional solution significantly compromised mesothelial cell viability and function in terms of mitochondrial activity ( p < 0.05) and stimulated IL-6 release ( p < 0.05). The bicarbonate/lactate fluid had no effect on cell viability or IL-6 release and turned out to be equivalent to the properties of the growth medium. Whereas lactate-incubated cells did not respond to IL-1β stimulation, bicarbonate/lactate-treated cells adequately increased IL-6 release after stimulation ( p < 0.0005). Release of TGF-β1 and CA125 did not differ between the different fluids and the control. Conclusions Due to the sustained equilibration process, the double-chamber cell culture model allows a more realistic insight into mesothelial cell viability and function in terms of PD. As in classic in vitro studies, an adverse effect of conventional PD solutions on mesothelial cells was overt in the present cell culture system. The neutral bicarbonate/lactate-buffered fluid with low GDP content, however, did not interfere with mesothelial cell vitality or function, indicating superior biocompatibility.

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Bergmanson, Jan P. G., Jan Johnsson, Per G. S??derberg, and Bo T. Philipson. "Lactate Levels in the Rabbit Cornea and Aqueous Humor Subsequent to Non-Gas Permeable Contact Lens Wear." Cornea 4, no. 3 (March 1985): 173???176. http://dx.doi.org/10.1097/00003226-198503000-00005.

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De Almeida, Karina Nascimento, Tarso Da Costa Alvim, Adriana Régia Marques de Souza, Gabriela Eustaquio Lacerda, Fernanda Aparecida Lima Silva Alvim, and Jonas Chaves Alvim. "HIDRÓLISE ENZIMÁTICA DA LACTOSE DE PERMEADO DE SORO." Revista do Instituto de Laticínios Cândido Tostes 70, no. 2 (September 3, 2015): 55. http://dx.doi.org/10.14295/2238-6416.v70i2.363.

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O permeado de soro é o resíduo do processo de concentração das proteínas do soro pelo método de ultrafiltração. Contém nutrientes importantes, como lactose, minerais e traços de proteínas e lipídeos. É um resíduo sem fim industrial estabelecido que causa sérios danos ao meio ambiente. Para que o seu aproveitamento seja integral e para permitir seu consumo por pessoas intolerantes ao açúcar do leite é preciso que a lactose seja hidrolisada. A hidrólise enzimática pela lactase (β-galactosidase) do fungo Kluyveromyces lactis é um método seguro e que não compromete a integridade dos demais nutrientes, permitindo assim o posterior uso do permeado como matériaprima. Este trabalho objetivou realizar ensaios de hidrólise enzimática da lactose de formulações de permeado de soro, em concentração de 0,2%, 0,7% e 1% nos tempos 30, 60 e 90 minutos com o pH do meio de 6,3 e temperatura de 37 ºC. As reações foram acompanhadas por cromatografia líquida de alta eficiência que mostrou que a partir da concentração enzimática de 0,7% no tempo de 30 minutos, as formulações se tornaram seguras para o consumo de intolerantes à lactose, de acordo com níveis mínimos estabelecidos pela legislação.

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Badaut, Jérôme, Lorenz Hirt, Cristina Granziera, Julien Bogousslavsky, Pierre J. Magistretti, and Luca Regli. "Astrocyte-Specific Expression of Aquaporin-9 in Mouse Brain is Increased after Transient Focal Cerebral Ischemia." Journal of Cerebral Blood Flow & Metabolism 21, no. 5 (May 2001): 477–82. http://dx.doi.org/10.1097/00004647-200105000-00001.

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Aquaporin-9 (AQP9) is a new member of the aquaporin family of water-selective channels mainly expressed in liver and testis, presenting the characteristic of also being permeable to various solutes, particularly lactate. Recent data have shown the presence of AQP9 on tanycytes in the rat brain. In the current study, the authors show the expression of AQP9 in astrocytes in the mouse brain and changes in its expression after cerebral ischemia. Indeed, in control mouse, the AQP9 immunolabeling is present on astrocytic processes bordering the subarachnoid space and ventricles. The labeling also is observed on astrocytes in the white matter, hippocampus, hypothalamus, and lateral septum. After focal transient ischemia, an increase of the immunolabeling is detected on astrocytes in periinfarct areas. This AQP9 distribution study in mouse brain suggests a role of AQP9 in water homeostasis in the central nervous system. Furthermore, the overexpression of AQP9 on astrocytes surrounding an ischemic lesion suggests that AQP9 may also play a role in the regulation of postischemia edema and, in view of its permeability to monocarboxylates, in the clearance of lactate from the ischemic focus.

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Yoshizato, K., A. Nishikawa, and T. Taira. "Functionally polarized layers formed by epidermal cells on a permeable transparent collagen film." Journal of Cell Science 91, no. 4 (December 1, 1988): 491–99. http://dx.doi.org/10.1242/jcs.91.4.491.

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Rat epidermal cells were cultured on a transparent collagen film, which was permeable to low Mr substances. Then the cells were bathed in both media (apical and basal), which were separated by the collagen membrane. The cells formed a multi-layered epidermal sheet with well-developed structures of desmosomes. This sheet on a permeable support was found to be an effective permeability barrier for glucose and amino acids. The epidermal layer showed functional polarity for the uptake and excretion of nutrients, metabolites and newly synthesized proteins: glucose and amino acids were taken up exclusively from the basal medium and lactate was secreted selectively into the same medium, whereas ammonia was secreted into the apical medium. The apical media became more acidic than the basal ones, presumably due to the preferential distribution of H+ transport systems on the apical side of the epidermal layer. The epidermal cells that expressed functional polarities in vitro as described above were able to proliferate and differentiate, and remained healthy for as long as at least 40 days even using a conventional culture medium with foetal calf serum, but without any special growth factors and feeder cells.

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Orsi, N. M., J. B. Reischl, and H. J. Leese. "Glucose metabolism of in vitro-produced bovine embryos in cell-free and co-culture systems." Proceedings of the British Society of Animal Science 2001 (2001): 216. http://dx.doi.org/10.1017/s1752756200005986.

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In vitro-produced (IVP) bovine embryos are used in a wide range of biotechnologies but develop less well than their in vivo counterparts and can give rise to foetal/neonatal anomalies after embryo transfer. The quality of bovine IVP embryos and the systems in which they are produced are traditionally assessed in terms of morphological and developmental criteria; namely, embryo grade and blastocyst formation rate. Lane and Gardner (1996) showed that mouse embryos selected for transfer on the basis of a low glycolytic activity (conversion of glucose to lactate), measured non-invasively, were 4 times more likely to implant than those selected randomly. Comparable data are not available for bovine embryos. The aim of this study was to assess linear glycolytic index of cattle blastocysts in vitro as a marker of viability. We have measured glucose consumption and lactate production by individual bovine IVP embryos grown in cell-free conditions and in a novel co-culture system (Orsi et al., 2000) involving confluent bovine oviduct epithelial cell monolayers on permeable supports. This preparation allows the epithelial cells to be fed by a nutritionally-rich medium via the physiological, basal, route, while the apical medium, containing the embryos, is more dilute, mimicking oviduct fluid.

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Kriz, Kirstin, Linda Kraft, Margareta Krook, and Dario Kriz. "Amperometric Determination ofl-Lactate Based on Entrapment of Lactate Oxidase on a Transducer Surface with a Semi-Permeable Membrane Using a SIRE Technology Based Biosensor. Application: Tomato Paste and Baby Food." Journal of Agricultural and Food Chemistry 50, no. 12 (June 2002): 3419–24. http://dx.doi.org/10.1021/jf0114942.

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Journal articles on the topic 'Lactate permease'

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