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Silanikove N, Shapiro F, Merin U, Lavon Y, Blum SE, Leitner G. Reduced use of glucose by normoxic cow's mammary gland under acute inflammation: an example of homeostatic aerobic glycolysis. RSC Adv 2016. [DOI: 10.1039/c6ra22934d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The concentration of glucose and glucose-derived carbons in milk reflect their concentrations in the mammary epithelial cell cytosol.
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Affiliation(s)
- Nissim Silanikove
- Department of Ruminant Science
- Animal Science
- The Volcani Center
- Bet Dagan 50250
- Israel
| | - Fira Shapiro
- Department of Ruminant Science
- Animal Science
- The Volcani Center
- Bet Dagan 50250
- Israel
| | - Uzi Merin
- Food Quality and Safety
- Postharvest and Food Sciences
- The Volcani Center
- Bet Dagan 50250
- Israel
| | - Yaniv Lavon
- Israel Cattle Breeders Association
- Caesarea
- Israel
| | - Shlomo E. Blum
- National Mastitis Reference Center
- Kimron Veterinary Institute
- Bet Dagan 50250
- Israel
| | - Gabriel Leitner
- National Mastitis Reference Center
- Kimron Veterinary Institute
- Bet Dagan 50250
- Israel
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Characterization of a unique Caulobacter crescentus aldose-aldose oxidoreductase having dual activities. Appl Microbiol Biotechnol 2015; 100:673-85. [PMID: 26428243 DOI: 10.1007/s00253-015-7011-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/04/2015] [Accepted: 09/14/2015] [Indexed: 10/23/2022]
Abstract
We describe here the characterization of a novel enzyme called aldose-aldose oxidoreductase (Cc AAOR; EC 1.1.99) from Caulobacter crescentus. The Cc AAOR exists in solution as a dimer, belongs to the Gfo/Idh/MocA family and shows homology with the glucose-fructose oxidoreductase from Zymomonas mobilis. However, unlike other known members of this protein family, Cc AAOR is specific for aldose sugars and can be in the same catalytic cycle both oxidise and reduce a panel of monosaccharides at the C1 position, producing in each case the corresponding aldonolactone and alditol, respectively. Cc AAOR contains a tightly-bound nicotinamide cofactor, which is regenerated in this oxidation-reduction cycle. The highest oxidation activity was detected on D-glucose but significant activity was also observed on D-xylose, L-arabinose and D-galactose, revealing that both hexose and pentose sugars are accepted as substrates by Cc AAOR. The configuration at the C2 and C3 positions of the saccharides was shown to be especially important for the substrate binding. Interestingly, besides monosaccharides, Cc AAOR can also oxidise a range of 1,4-linked oligosaccharides having aldose unit at the reducing end, such as lactose, malto- and cello-oligosaccharides as well as xylotetraose. (1)H NMR used to monitor the oxidation and reduction reaction simultaneously, demonstrated that although D-glucose has the highest affinity and is also oxidised most efficiently by Cc AAOR, the reduction of D-glucose is clearly not as efficient. For the overall reaction catalysed by Cc AAOR, the L-arabinose, D-xylose and D-galactose were the most potent substrates.
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Zhao W, Wang J, Varghese M, Ho L, Mazzola P, Haroutunian V, Katsel PL, Gibson GE, Levine S, Dubner L, Pasinetti GM. Impaired mitochondrial energy metabolism as a novel risk factor for selective onset and progression of dementia in oldest-old subjects. Neuropsychiatr Dis Treat 2015; 11:565-74. [PMID: 25784811 PMCID: PMC4356684 DOI: 10.2147/ndt.s74898] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Recent evidence shows that Alzheimer disease (AD) dementia in the oldest-old subjects was associated with significantly less amyloid plaque and fibrillary tangle neuropathology than in the young-old population. In this study, using quantitative (q) PCR studies, we validated genome-wide microarray RNA studies previously conducted by our research group. We found selective downregulation of mitochondrial energy metabolism genes in the brains of oldest-old, but not young-old, AD dementia cases, despite a significant lack of classic AD neuropathology features. We report a significant decrease of genes associated with mitochondrial pyruvate metabolism, the tricarboxylic acid cycle (TCA), and glycolytic pathways. Moreover, significantly higher levels of nitrotyrosylated (3-NT)-proteins and 4-hydroxy-2-nonenal (HNE) adducts, which are indexes of cellular protein oxidation and lipid peroxidation, respectively, were detected in the brains of oldest-old subjects at high risk of developing AD, possibly suggesting compensatory mechanisms. These findings support the hypothesis that although oldest-old AD subjects, characterized by significantly lower AD neuropathology than young-old AD subjects, have brain mitochondrial metabolism impairment, which we hypothesize may selectively contribute to the development of dementia. Outcomes from this study provide novel insights into the molecular mechanisms underlying clinical dementia in young-old and oldest-old AD subjects and provide novel strategies for AD prevention and treatment in oldest-old dementia cases.
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Affiliation(s)
- Wei Zhao
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA
| | - Jun Wang
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA
| | - Merina Varghese
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lap Ho
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA
| | - Paolo Mazzola
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Department of Health Sciences, University of Milano-Bicocca, Monza, Italy
| | - Vahram Haroutunian
- Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA ; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pavel L Katsel
- Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA ; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gary E Gibson
- Department of Neurology and Neuroscience, Weill Cornell Medical College, Burke Medical Research Institute, New York, NY, USA
| | - Samara Levine
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lauren Dubner
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Giulio Maria Pasinetti
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Geriatric Research Education Clinical Center - James J Peter VA Medical Center, Bronx, NY, USA ; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA ; Department of Geriatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Abstract
Cofactor specificities of glycolytic enzymes in Clostridium thermocellum were studied with cellobiose-grown cells from batch cultures. Intracellular glucose was phosphorylated by glucokinase using GTP rather than ATP. Although phosphofructokinase typically uses ATP as a phosphoryl donor, we found only pyrophosphate (PPi)-linked activity. Phosphoglycerate kinase used both GDP and ADP as phosphoryl acceptors. In agreement with the absence of a pyruvate kinase sequence in the C. thermocellum genome, no activity of this enzyme could be detected. Also, the annotated pyruvate phosphate dikinase (ppdk) is not crucial for the generation of pyruvate from phosphoenolpyruvate (PEP), as deletion of the ppdk gene did not substantially change cellobiose fermentation. Instead pyruvate formation is likely to proceed via a malate shunt with GDP-linked PEP carboxykinase, NADH-linked malate dehydrogenase, and NADP-linked malic enzyme. High activities of these enzymes were detected in extracts of cellobiose-grown cells. Our results thus show that GTP is consumed while both GTP and ATP are produced in glycolysis of C. thermocellum. The requirement for PPi in this pathway can be satisfied only to a small extent by biosynthetic reactions, in contrast to what is generally assumed for a PPi-dependent glycolysis in anaerobic heterotrophs. Metabolic network analysis showed that most of the required PPi must be generated via ATP or GTP hydrolysis exclusive of that which happens during biosynthesis. Experimental proof for the necessity of an alternative mechanism of PPi generation was obtained by studying the glycolysis in washed-cell suspensions in which biosynthesis was absent. Under these conditions, cells still fermented cellobiose to ethanol.
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Redirecting carbon flux through exogenous pyruvate kinase to achieve high ethanol yields in Clostridium thermocellum. Metab Eng 2012. [PMID: 23202749 DOI: 10.1016/j.ymben.2012.11.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In Clostridium thermocellum, a thermophilic anaerobic bacterium able to rapidly ferment cellulose to ethanol, pyruvate kinase (EC 2.7.1.40) is absent based on both the genome sequence and enzymatic assays. Instead, a new pathway converting phosphoenolpyruvate to pyruvate via a three-step pathway involving phosphoenolpyruvate carboxykinase, NADH-linked malate dehydrogenase, and NADP-dependent malic enzyme has been found. We examined the impact of targeted modification of enzymes associated with this pathway, termed the "malate shunt", including expression of the pyruvate kinase gene from Thermoanaerobacterium saccharolyticum, mutation of the phosphoenolpyruvate carboxykinase and deletion of malic enzyme gene. Strain YD01 with exogenous pyruvate kinase, in which phosphoenolpyruvate carboxykinase expression was diminished by modifying the start codon from ATG to GTG, exhibited 3.25-fold higher ethanol yield than the wild-type strain. A second strain, YD02 with exogenous pyruvate kinase, in which the gene for malic enzyme and part of malate dehydrogenase were deleted, had over 3-fold higher ethanol yield than the wild-type strain.
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Wang J, Ferruzzi MG, Varghese M, Qian X, Cheng A, Xie M, Zhao W, Ho L, Pasinetti GM. Preclinical study of dimebon on β-amyloid-mediated neuropathology in Alzheimer's disease. Mol Neurodegener 2011; 6:7. [PMID: 21247479 PMCID: PMC3035024 DOI: 10.1186/1750-1326-6-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/19/2011] [Indexed: 12/04/2022] Open
Abstract
Background Dimebon is a retired non-selective antihistamine drug currently being investigated as a therapeutic agent for the treatment of Alzheimer's disease (AD). Results from several completed clinical trials are mixed and contradictory. Proper interpretations of these clinical observations, as well as future development of dimebon in AD treatment are complicated by the lack of concrete information on the mechanisms by which dimebon might benefit AD. Results The present studies are designed specifically to assess whether dimebon might modulate β-amyloid (Aβ)-mediated responses which are central to the development and progression of AD dementia. We found that dimebon is bioavailable in the brains of mice following oral administration. AD mice chronically treated with dimebon exhibited a trend of improvement in spatial memory function without affecting the levels of total Aβ as well as soluble oligomeric Aβ in the brain. The same trend of behavior improvement is also seen in wild type animals chronically treated with dimebon. Conclusion Collectively, our preclinical studies using the TgCRND8 AD mouse model demonstrated that dimebon might have some beneficial effect in improving cognitive function independent of Alzheimer's disease-type Aβ-related mechanisms or global energy metabolism in the brain. Observations from our study and others suggesting dimebon might improve cognition in wild type mice and rats raises the possibility that dimebon might be able to benefit cognitive function in patients with other neurodegenerative disorders, such as Huntington's disease, or in the aging population. Additional studies will be necessary to clarify the mechanisms by which dimebon might directly or indirectly benefit cognitive function.
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Affiliation(s)
- Jun Wang
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029 USA.
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Cheng B, Kimura T. The distribution of cholesterol and phospholipid composition in submitochondrial membranes from bovine adrenal cortex: fundamental studies of steroidogenic mitochondria. Lipids 1983; 18:577-84. [PMID: 6633163 DOI: 10.1007/bf02534665] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The cholesterol contents and phospholipid compositions of mitochondria, microsomes and submitochondrial membranes from bovine adrenal cortex have been analyzed quantitatively. From our results, the following cholesterol contents were obtained: mitochondria, 6.2 +/- 0.9 mol %; microsomes, 18.4 +/- 2.8 mol %; mitochondrial inner membrane, 2.8 +/- 0.6 mol %; and mitochondrial outer membrane, 8.3 +/- 1.3 mol %. In addition, the phospholipid compositions of the mitochondrial inner and outer membranes were determined for the first time. Cardiolipin was found to be enriched in the inner membrane, whereas phosphatidylinositol was richer in the outer membrane. The general features of phospholipid compositions in the submitochondrial membranes resembled that of rat liver mitochondria.
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Coolbaugh JC, Progar JJ, Weiss E. Enzymatic activities of cell-free extracts of Rickettsia typhi. Infect Immun 1976; 14:298-305. [PMID: 820644 PMCID: PMC420876 DOI: 10.1128/iai.14.1.298-305.1976] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cell-free extracts of Rickettsia typhi were tested for activities of enzymes of the tricarboxylic acid cycle, of glutamate catabolism, and of glycolysis. The organisms were grown in the yolk sacs of chicken embryos, harvested shortly before the time of embryo death, purified by Renografin density gradient centrifugation, and ruptured in a French pressure cell. The following enzymatic activities were demonstrated: high levels of malate dehydrogenase (MDH), moderate levels of glutamate-oxaloacetate transaminase, glutamate, succinate, and isocitrate dehydrogenases, and citrate synthase, and low levels of glutamate-pyruvate transaminase. The specific activities of some of these enzymes were higher when the rickettsiae were harvested at a time of active proliferation, 3 to 4 days prior to embryo death. Rickettsial MDH was differentiated from host MDH by its migration pattern on polyacrylamide gel electrophoresis. The activities of MDH and two other dehydrogenases, demonstrable after the cells had been disrupted, were absent from purified, intact rickettsial preparations. No activity was detected for glucose-6-phosphate, 6-phosphogluconate, glyceraldehyde-3-phosphate, lactate dehydrogenases, phosphoglucose isomerase, fructoaldolase, or pyruvate kinase. Our results suggest that extracts of R. typhi that contain demonstrable enzymes involved in the catabolism of glutamate and tricarboxylic acid cycle intermediates, unlike Coxiella burnetti, lack detectable glycolytic activity.
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C-AMPBELL J, Chang TM. Epnzymatric recycling of coenzymes by a multi-enzyme system immobilized within semipermeable collodion microcapsules. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 397:101-9. [PMID: 1148255 DOI: 10.1016/0005-2744(75)90183-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hexokinase (ATP:D-glucose 6-phosphotransferase EC 2.7.1.2) and pyruvate kinase (ATP:pyruvate 2-0-phosphotransferase EC 2.7.1.40) were co-immobilized within semipermeable collodion microcapsules. The resulting microcapsules displayed excellent hexokinase and pyruvate kinase activities, with the measured pyruvate kinase activity considerably greater than that measured for hexokinase. The co-immobilized enzymes, when used sequentially were capable of recycling both ATP and ADP when exposed to the appropriate conditions. Furthermore, when exposed to limiting amounts of coenzyme, the cycles were capable of reusing the total amount of coenzyme supplied at least three times in 90 min. The use of microencapsulation to produce partially "self sufficient" enzyme systems is discussed.
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