Effect of pyruvate kinase overproduction on glucose metabolism of Lactococcus lactis

Microbiology ◽  
2004 ◽  
Vol 150 (4) ◽  
pp. 1103-1111 ◽  
Author(s):  
Ana Ramos ◽  
Ana Rute Neves ◽  
Rita Ventura ◽  
Christopher Maycock ◽  
Paloma López ◽  
...  
Keyword(s):  
Pyruvate Kinase ◽  
Lactococcus Lactis ◽  
Expression System ◽  
Lactate Production ◽  
Fold Increase ◽  
Glycolytic Flux ◽  
Anaerobic Conditions ◽  
Lactate Dehydrogenase Activity ◽  
Glucose Depletion

Lactococcus lactis strain NZ9000(pNZpyk), which overproduces pyruvate kinase (PK), was constructed. The pNZpyk plasmid carries the P nisA –pyk transcriptional fusion, and the overexpression of its pyk gene was accomplished by using the nisin-inducible expression system of the NZ9000 strain. In vivo 13C- and 31P-NMR spectroscopy was used to evaluate the effect of this modification on the metabolism of glucose in non-growing cells. A detailed description of the kinetics of glucose, end products, glycolytic intermediates, NAD+ and NADH was obtained. A 15-fold increase in the level of PK did not increase the overall glycolytic flux, which, on the contrary, was slightly reduced. Significant differences were observed in (i) the level of 3-phosphoglycerate (3-PGA) and phosphoenolpyruvate (PEP), metabolites associated with starvation; (ii) the rate of fructose 1,6-bisphosphate (FBP) depletion upon glucose exhaustion; and (iii) the NAD+/NADH ratio during glucose catabolism. In the mutant, the rate of FBP consumption after glucose depletion was notably accelerated under anaerobic conditions, whereas 3-PGA and PEP decreased to undetectable levels. Furthermore, the level of NAD+ decreased steadily during the utilization of glucose, probably due to the unanticipated reduction in the lactate dehydrogenase activity in comparison with the control strain, NZ9000(pNZ8020). The results show that PK is an important bottleneck to carbon flux only when glucose becomes limiting; in the overproducer this constriction was no longer present, as evidenced by the faster FBP consumption and lack of accumulation of 3-PGA and PEP in anaerobic as well as aerobic conditions. Despite these clear changes, the PK-overproducing strain showed typical homolactic metabolism under anaerobic conditions, as did the strain harbouring the vector plasmid without the pyk insert. However, under an oxygen atmosphere, there was increased channelling of carbon to the production of acetate and acetoin, to the detriment of lactate production.

scholarly journals Responses of hypertrophied myocytes to reactive species: implications for glycolysis and electrophile metabolism

2011 ◽  
Vol 435 (2) ◽  
pp. 519-528 ◽  
Author(s):  
Brian E. Sansbury ◽  
Daniel W. Riggs ◽  
Robert E. Brainard ◽  
Joshua K. Salabei ◽  
Steven P. Jones ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Oxygen Consumption ◽  
Energy Demand ◽  
Lactate Production ◽  
Fold Increase ◽  
Cellular Protein ◽  
Reactive Species ◽  
Neonatal Rat ◽  
Glycolytic Flux ◽  
Rat Cardiomyocytes

During cardiac remodelling, the heart generates higher levels of reactive species; yet an intermediate ‘compensatory’ stage of hypertrophy is associated with a greater ability to withstand oxidative stress. The mechanisms underlying this protected myocardial phenotype are poorly understood. We examined how a cellular model of hypertrophy deals with electrophilic insults, such as would occur upon ischaemia or in the failing heart. For this, we measured energetics in control and PE (phenylephrine)-treated NRCMs (neonatal rat cardiomyocytes) under basal conditions and when stressed with HNE (4-hydroxynonenal). PE treatment caused hypertrophy as indicated by augmented atrial natriuretic peptide and increased cellular protein content. Hypertrophied myocytes demonstrated a 2.5-fold increase in ATP-linked oxygen consumption and a robust augmentation of oligomycin-stimulated glycolytic flux and lactate production. Hypertrophied myocytes displayed a protected phenotype that was resistant to HNE-induced cell death and a unique bioenergetic response characterized by a delayed and abrogated rate of oxygen consumption and a 2-fold increase in glycolysis upon HNE exposure. This augmentation of glycolytic flux was not due to increased glucose uptake, suggesting that electrophile stress results in utilization of intracellular glycogen stores to support the increased energy demand. Hypertrophied myocytes also had an increased propensity to oxidize HNE to 4-hydroxynonenoic acid and sustained less protein damage due to acute HNE insults. Inhibition of aldehyde dehydrogenase resulted in bioenergetic collapse when myocytes were challenged with HNE. The integration of electrophile metabolism with glycolytic and mitochondrial energy production appears to be important for maintaining myocyte homoeostasis under conditions of increased oxidative stress.

scholarly journals The Plasmodium falciparum circumsporozoite protein produced in Lactococcus lactis is pure and stable

2019 ◽  
Vol 295 (2) ◽  
pp. 403-414 ◽  
Author(s):  
Susheel K. Singh ◽  
Jordan Plieskatt ◽  
Bishwanath Kumar Chourasia ◽  
Vandana Singh ◽  
Judith M. Bolscher ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Lactococcus Lactis ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Expression System ◽  
Surface Protein ◽  
Circumsporozoite Protein ◽  
Full Length

The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis–derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro. We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.

Metabolism of the renal medulla

1965 ◽  
Vol 208 (3) ◽  
pp. 541-545 ◽  
Author(s):  
David Bernanke ◽  
Franklin H. Epstein
Keyword(s):  
Oxygen Uptake ◽  
Energy Production ◽  
Critical Role ◽  
Oxidative Degradation ◽  
Lactate Production ◽  
Renal Medulla ◽  
Anaerobic Conditions ◽  
Atp Generation ◽  
Aerobic And Anaerobic

Slices of the inner medulla of kidneys removed from hydropenic dogs were incubated with glucose and succinate under aerobic and anaerobic conditions. When theoretical maximum ATP generation was calculated from oxygen uptake and lactate production, the calculated energy production from oxidative degradation of glucose was twice that from glycolysis. Hypertonic solutions of NaCl and urea, in concentrations comparable to those present in vivo, depressed both lactate production from glucose and oxygen uptake in succinate to the same extent. Studies of CO2 generation by medullary slices from labeled glucose in 100% O2 showed a C1/C6 ratio of 3.7, compared to 1.7 for cortex. It is suggested that oxidative metabolism may play a critical role in the renal medulla of intact animals in providing energy for active transport of sodium and thereby facilitating the process by which urine is concentrated.

scholarly journals Transiently Expressed Mistletoe Lectin II in Nicotiana benthamiana Demonstrates Anticancer Activity In Vitro

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2562
Author(s):  
Milena Mazalovska ◽  
J. Calvin Kouokam
Keyword(s):  
Anticancer Activity ◽  
Nicotiana Benthamiana ◽  
Expression System ◽  
Gel Filtration ◽  
A549 Cells ◽  
Fold Increase ◽  
Carbohydrate Binding ◽  
Mistletoe Lectin

Mistletoe (Viscum album) extracts have been used as alternative and complementary therapeutic preparations in multiple cancers for decades. Mistletoe lectins (ML-I, ML-II, and ML-III) are considered to be the main anticancer components of such preparations. In the present study, ML-II was transiently expressed in Nicotiana benthamiana using the pEAQ-HT expression system. Expression levels of up to 60 mg/kg of the infiltrated plant tissue were obtained, and a three-fold increase was achieved by adding the endoplasmic reticulum (ER) retention signal KDEL to the native ML-II sequence. The native protein containing His-tag and KDEL was purified by immobilized metal affinity chromatography (IMAC) and gel filtration. We found that the recombinant ML-II lectin was glycosylated and retained its carbohydrate-binding activity. In addition, we demonstrated that plant produced ML-II displayed anticancer activity in vitro, inhibiting non-small cell lung cancer H460 and A549 cells with EC50 values of 4 and 3.5 µg/mL, respectively. Annexin V-448A and PI double staining revealed that cell cytotoxicity occurred via apoptosis induction. These results indicate that ML-II transiently expressed in N. benthamiana plants is a promising candidate as an anticancer agent, although further optimization of production and purification methods is required to enable further in vitro testing, as well as in vivo assays.

Cellular Bioenergetics in Lymphoid Neoplasia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-25-SCI-25 ◽  
Author(s):  
Matthew Vander Heiden
Keyword(s):  
Cancer Cells ◽  
Pyruvate Kinase ◽  
Cell Biology ◽  
Aerobic Glycolysis ◽  
Lactate Production ◽  
Proliferating Cells ◽  
Hematopoietic Stem ◽  
Oxygen Levels ◽  
Lymphoid Neoplasia

Abstract Abstract SCI-25 Many cancer cells metabolize glucose by aerobic glycolysis, a phenomenon characterized by increased glycolysis with lactate production and decreased oxidative phosphorylation. We have argued that alterations in cell metabolism associated with cancer may be selected by cancer cells to meet the distinct metabolic needs of proliferation. Unlike metabolism in differentiated cells, which is geared toward efficient ATP generation, the metabolism in cancer cells must be adapted to facilitate the accumulation of biomass. Cancer cells divert a larger fraction of their nutrient metabolism to pathways other than mitochondrial respiration regardless of oxygen availability. Nevertheless, oxygen levels still influence how nutrients are metabolized. We have found that the source of carbon used in various anabolic processes varies based on oxygen levels. Furthermore, the enzymes used to metabolize nutrients can also differ based on the cellular context. This includes regulation of isocitrate dehydrogenase, an enzyme that is mutated in some cancers. There is also strong selection for use of the M2 isoform of pyruvate kinase (PK-M2) to metabolize glucose in cancer cell lines. However, evidence from mouse models suggests that PK-M2 is dispensable for glucose metabolism by many tumors in vivo, suggesting an alternate pathway to convert phosphoenolpyruvate to pyruvate can be used to metabolize glucose. This regulation of pyruvate kinase also plays an important role in hematopoietic stem cell biology. Together, these findings argue that distinct metabolic phenotypes exist among proliferating cells, and both environmental and genetic factors influence how metabolism is regulated to support cell growth. Disclosures: Vander Heiden: Agios Pharmaceuticals: Consultancy, Equity Ownership.

Regulation of glycolysis in rat aorta

1984 ◽  
Vol 247 (1) ◽  
pp. C107-C114 ◽  
Author(s):  
H. Kutchai ◽  
L. M. Geddis
Keyword(s):  
Incubation Medium ◽  
Lactate Production ◽  
Fold Increase ◽  
Rat Aorta ◽  
Mitochondrial Atpase ◽  
Anaerobic Conditions ◽  
Experimental Conditions ◽  
Exogenous Glucose ◽  
Atp Generation ◽  
Almost All

Certain factors that might contribute to the regulation of the rate of glycolysis by rat aorta were investigated. Rat aortic rings were incubated with [14C]glucose, and the release of [14C]lactate was determined. There was good agreement between the lactate production estimated by enzymatic assay and by [14C]lactate release, suggesting that almost all the lactate produced under our experimental conditions was derived from exogenous glucose. When the glucose concentration in the medium was 10 mM or higher, the rate of glucose transport did not limit the rate of lactate production. In most cases studies were done both aerobically and anaerobically. In Hanks' Balanced Salt Solution the aerobic rate of lactate production was 18% of the anaerobic rate. We tested the effects on glycolysis of agents that alter ATP generation by mitochondria or ATP splitting by Na+-K+-ATPase or the mitochondrial ATPase. Under aerobic conditions, ouabain (5 mM) caused a 54% decrease in lactate production, and gramicidin (5 micrograms/ml) caused a 45% increase. Under anaerobic conditions, neither ouabain nor gramicidin affected lactate production. Aerobically dinitrophenol (25 microM) and carboxyatractyloside (0.5 mM) caused substantial increases in lactate production, 72 and 98% respectively. Under anaerobic conditions the effects of dinitrophenol and carboxyatractyloside were much smaller, with dinitrophenol causing a 15% increase and carboxyatractyloside a 12% decrease in lactate production. Increasing the concentration of phosphate in the incubation medium caused marked increases in lactate production. Both aerobically and anaerobically, shifting from 1.3 to 50 mM phosphate in the incubation medium caused a 3.5-fold increase in lactate production.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Co-expression With Replicating Vector Overcoming Competitive Effects Derived by a Companion Protease Inhibitor in Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiexue Ma ◽  
Xiangzhen Ding ◽  
Zhiying Li ◽  
Sheng Wang
Keyword(s):  
Protease Inhibitor ◽  
Molecular Farming ◽  
Expression System ◽  
Fold Increase ◽  
Protective Effects ◽  
Competitive Effects ◽  
Inoculum Dose ◽  
Plant Expression Systems

Plant-based expression platforms are currently gaining acceptance as a viable alternative for the production of recombinant proteins (RPs), but the degradation of RPs by proteases in cells hinders their superb potentials. Co-expression of a protease inhibitor (PI) shows promise as a strategy to prevent RP from proteolytic degradation in plants. However, competitive effects behind the PI-RP co-expression system may mask or obfuscate the in situ protective effects of a companion PI. Here, we explored the competitive effects by co-expressing reteplase (rPA) with three unrelated PIs, namely NbPR4, HsTIMP, and SlCYS8, in Nicotiana benthamiana leaves. Remarkably, the accumulation of rPA was significantly repressed by each of the three PIs, suggesting that the competitive effects may be common among the PIs. The repression can be attenuated by reducing the PI inoculum dose in the co-inoculation mixtures, showing a negative correlation between the PI abundance of the PI-RP system and competitive effects. Interestingly, when a replicating vector was used to modulate the relative abundance of PI and RP in vivo, rPA was still boosted even at the maximal testing dose of PI, indicating that the competitive effects reduced to an ignorable level by this in vivo approach. Furthermore, a 7- to 12-fold increase of rPA was achieved, proving that it is a useful way for stimulating the potentials of a companion PI by overcoming competitive effects. And, this approach can be applied to molecular farming for improving the RP yields of plant expression systems.

scholarly journals Thyroid Hormone Enhances Angiogenesis and the Warburg Effect in Squamous Cell Carcinomas

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2743
Author(s):  
Caterina Miro ◽  
Annarita Nappi ◽  
Annunziata Gaetana Cicatiello ◽  
Emery Di Cicco ◽  
Serena Sagliocchi ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Squamous Cell ◽  
Warburg Effect ◽  
Lactate Production ◽  
Metabolic Stress ◽  
Cell Types ◽  
Metabolic Reprogramming ◽  
Glycolytic Flux ◽  
The Warburg Effect

Cancer angiogenesis is required to support energetic demand and metabolic stress, particularly during conditions of hypoxia. Coupled to neo-vasculogenesis, cancer cells rewire metabolic programs to sustain growth, survival and long-term maintenance. Thyroid hormone (TH) signaling regulates growth and differentiation in a variety of cell types and tissues, thus modulating hyper proliferative processes such as cancer. Herein, we report that TH coordinates a global program of metabolic reprogramming and induces angiogenesis through up-regulation of the VEGF-A gene, which results in the enhanced proliferation of tumor endothelial cells. In vivo conditional depletion of the TH activating enzyme in a mouse model of cutaneous squamous cell carcinoma (SCC) reduces the concentration of TH in the tumoral cells and results in impaired VEGF-A production and attenuated angiogenesis. In addition, we found that TH induces the expression of the glycolytic genes and fosters lactate production, which are key traits of the Warburg effect. Taken together, our results reveal a TH–VEGF-A–HIF1α regulatory axis leading to enhanced angiogenesis and glycolytic flux, which may represent a target for SCC therapy.

scholarly journals Specificity Mutants of the Binding Protein of the Oligopeptide Transport System of Lactococcus lactis

2000 ◽  
Vol 182 (6) ◽  
pp. 1600-1608 ◽  
Author(s):  
Antonia Picon ◽  
Edmund R. S. Kunji ◽  
Frank C. Lanfermeijer ◽  
Wil N. Konings ◽  
Bert Poolman
Keyword(s):  
Lactococcus Lactis ◽  
Fold Increase ◽  
Binding Activity ◽  
Kinetic Properties ◽  
Wild Type ◽  
Mutant Proteins ◽  
Serovar Typhimurium ◽  
Peptide Binding Site ◽  
Oligopeptide Transport

ABSTRACT The kinetic properties of wild-type and mutant oligopeptide binding proteins of Lactococcus lactis were determined. To observe the properties of the mutant proteins in vivo, the oppAgene was deleted from the chromosome of L. lactis to produce a strain that was totally defective in oligopeptide transport. Amplified expression of the oppA gene resulted in an 8- to 12-fold increase in OppA protein relative to the wild-type level. The amplified expression was paralleled by increased bradykinin binding activity, but had relatively little effect on the overall transport of bradykinin via Opp. Several site-directed mutants were constructed on the basis of a comparison of the primary sequences of OppA fromSalmonella enterica serovar Typhimurium and L. lactis, taking into account the known structure of the serovar Typhimurium protein. Putative peptide binding-site residues were mutated. All the mutant OppA proteins exhibited a decreased binding affinity for the high-affinity peptide bradykinin. Except for OppA(D471R), the mutant OppA proteins displayed highly defective bradykinin uptake, whereas the transport of the low-affinity substrate KYGK was barely affected. Cells expressing OppA(D471R) had a similarKm for transport, whereas theV max was increased more than twofold as compared to the wild-type protein. The data are discussed in the light of a kinetic model and imply that the rate of transport is determined to a large extent by the donation of the peptide from the OppA protein to the translocator complex.

Sign in / Sign up

Export Citation Format

Share Document