Dependent Dehydrogenase Activity Research Articles

The Effect of Pro- and Eukaryotic Inductors on the Synthesis and Antimicrobial Activity of Acinetobacter calcoaceticus IMV B-7241 Surfactants

By now, the mixed cultivation ("co-cultivation") of antimicrobial compound producers with other microorganisms or the introduction of biological inductors in different physiological states (live and inactivated cells, as well as the corresponding supernatants) into the culture medium is a simple, cheap, and effective way to increase the synthesis of practically important microbial metabolites and regulate their biological activity. In most studies, researchers use bacterial strains of various species as inductors, however, in recent years, there have been an increasing number of publications reporting the use of eukaryotic inductors, in response to which there's observed an increase in the synthesis of antimicrobial compounds by the bacterial producers. In addition, the effectiveness of biological inductors depends on the conditions of their cultivation and physiological state. Aim. To study the effect of the methods of preparation and physiological state of biological inductors (gram-negative bacteria Enterobacter cloacae C-8 and yeast Saccharomyces cerevisiae BTM-1) on the activity of biosynthetic enzymes and antimicrobial activity of Acinetobacter calcoaceticus IMV B-7241 surfactants. Methods. Purified glycerol and crude glycerol in equimolar carbon concentration were used as a substrate for cultivation of A. calcoaceticus IMV B-7241. The microbial inductors were grown on both agar and liquid media with glucose as a carbon source. Live or inactivated cells of S. cerevisiae BTM-1 or E. cloacae C-8, as well as the corresponding supernatant, were added to the medium in an amount of 2.5–10 % (v/v). The extracellular surfactants were obtained from the supernatant of the culture liquid by extraction with a mixture of chloroform and methanol (2:1). The antimicrobial activity of surfactants against bacterial (Bacillus subtilis BT-2, Escherichia coli IEM-1, Staphylococcus aureus BMS-1, Pseudomonas sp. MI-2) and yeast (Candida albicans D-6 and Candida tropicalis PE-2) test cultures was determined by the indicator of the minimum inhibitory concentration. The activity of enzymes for the biosynthesis of surface-active glyco- (phosphoenolpyruvate carboxylase, phosphoenolpyruvate synthetase, phosphoenolpyruvate carboxykinase, trehalose phosphate synthase) and aminolipids (NADP+-dependent glutamate dehydrogenase) was analyzed in cell-free extracts obtained after sonication of cells. Results. The introduction into the culture medium of A. calcoaceticus of IMV B-7241 with glycerol of various purification degrees, both pro- and eukaryotic inductors in different physiological states was accompanied by the synthesis of surfactants, the antimicrobial activity of which against the test cultures was higher by one to two orders of magnitude compared to preparations obtained without inductors. It was found that E. cloacae C-8 cells grown in liquid medium were slightly more effective as inductors than those grown in agar medium: the minimum inhibitory concentrations against bacterial and yeast cultures of surfactants synthesised in their presence were 1–6 and 2.5–8 μg/mL, respectively. When live S. cerevisiae BTM-1 or E. cloacae C-8 cells were used as inductors, the production of microbial surfactants with higher antimicrobial activity than those synthesized in the presence of inactivated cells or supernatants was observed: the minimum inhibitory concentrations against the test cultures were in the range of 0.85–16, 2–20 and 1.5–22 μg/mL, respectively. The higher antimicrobial activity of surfactants synthesized in the presence of a pro- or eukaryotic inductor in the medium with purified glycerol may be caused by an increase of aminolipids in their composition, as evidenced by a 1.6–2.1-fold increase in NADP+-dependent glutamate dehydrogenase activity in A. calcoaceticus IMV B-7241 cells compared to the values of cultivation without inductors. The same level of activity of this enzyme during the cultivation of the IMV B-7241 strain in the medium with crude glycerol in the presence of inductors and without them may indicate the synthesis under such conditions of other, than aminolipids, metabolites with antimicrobial activity. Conclusions. As a result of this study, it was established that the antimicrobial activity of A. calcoaceticus IMV B-7241 surfactants can be increased by introducing pro- and eukaryotic inductors in the form of live or inactivated cells, as well as the corresponding supernatants into the medium with glycerol of different degrees of purification.

Distribution and Functional Analysis of Isocitrate Dehydrogenases across Kinetoplastids.

Isocitrate dehydrogenase is an enzyme converting isocitrate to α-ketoglutarate in the canonical tricarboxylic acid (TCA) cycle. There are three different types of isocitrate dehydrogenase documented in eukaryotes. Our study points out the complex evolutionary history of isocitrate dehydrogenases across kinetoplastids, where the common ancestor of Trypanosomatidae and Bodonidae was equipped with two isoforms of the isocitrate dehydrogenase enzyme: the NADP+-dependent isocitrate dehydrogenase 1 with possibly dual localization in the cytosol and mitochondrion and NADP+-dependent mitochondrial isocitrate dehydrogenase 2. In the extant trypanosomatids, isocitrate dehydrogenase 1 is present only in a few species suggesting that it was lost upon separation of Trypanosoma spp. and replaced by the mainly NADP+-dependent cytosolic isocitrate dehydrogenase 3 of bacterial origin in all the derived lineages. In this study, we experimentally demonstrate that the omnipresent isocitrate dehydrogenase 2 has a dual localization in both mitochondrion and cytosol in at least four species that possess only this isoform. The apparent lack of the NAD+-dependent isocitrate dehydrogenase activity in trypanosomatid mitochondrion provides further support to the existence of the noncanonical TCA cycle across trypanosomatids and the bidirectional activity of isocitrate dehydrogenase 3 when operating with NADP+ cofactor instead of NAD+. This observation can be extended to all 17 species analyzed in this study, except for Leishmania mexicana, which showed only low isocitrate dehydrogenase activity in the cytosol. The variability in isocitrate oxidation capacity among species may reflect the distinct metabolic strategies and needs for reduced cofactors in particular environments.

Targeting Mitochondrial Calcium Uptake to Eradicate Venetoclax-Resistant Acute Myeloid Leukemia Stem Cells

Introduction Previously, we demonstrated that human leukemia stem cells (LSCs) are preferentially reliant on oxidative phosphorylation (OXPHOS) for survival. Furthermore, inhibition of BCL2 with venetoclax (ven) acts to suppress OXPHOS, leading to the eradication of LSCs. While the activity of ven in targeting LSCs is well-established, nearly all patients eventually develop disease that is resistant to treatment. Thus, in the present study, we sought to better understand the biological properties of ven-resistant LSCs. We reasoned that the expression of known BCL2 interacting proteins in ven-sensitive (ven-S) vs. ven-resistant (ven-R) would provide insights on resistance mechanisms. Initial findings showed that one of the most prevalent molecular features observable in ven resistant LSCs is up-regulation of calcium signaling. As calcium is a critical modulator of multiple enzymes involved in OXPHOS, we hypothesized that the maintenance of high mitochondrial calcium could contribute to circumventing the effects of ven treatment. Thus, the present study was designed to test the functional role of calcium in ven-R LSCs and to determine whether targeting mitochondrial calcium transport represents a therapeutic vulnerability. Methods CITE-Seq analysis was performed on 25 AML patient specimens and analyzed using TotalVI. All studies were conducted in primary human AML specimens with LSCs defined by a ROS-low phenotype. Mitochondrial calcium measurements were done using Rhod2-AM. OXPHOS activity was measured through seahorse and enzyme activity assays. Genetic perturbations were done using siRNA via electroporation and confirmed with western blot. LSC function was assessed by colony formation assays and PDX experiments. PDX experiments were also used to determine efficacy of tumor reduction in ven-R AML samples. Results To identify unique features of ven resistant LSCs, we performed single cell RNA-seq on known ven-S vs. ven-R specimens. As shown in Fig 1, resistant LSCs had higher expression of genes involved in calcium transport into the mitochondria, which was reflected by increased steady-state mitochondrial calcium levels compared to ven-S LSCs. Thus, we investigated targeting of the calcium uniporter, MCU, as a means to reduce mitochondrial calcium levels. Treatment of primary LSCs with pharmacological MCU inhibitors (Ru265, MCUi4), as well as genetic inhibition of MCU with siRNAs, led to decreased mitochondrial calcium levels, suppression of calcium dependent TCA cycle dehydrogenase activity, reduced OXPHOS activity, and impaired LSC function as measured by colony assays (CFU) and engraftment in immune deficient mice. Importantly, MCU inhibition did not significantly impair normal stem/progenitor cells. To develop a clinically relevant system, we investigated bio-available agents known to inhibit MCU. Intriguingly, the only known FDA-approved direct MCU inhibitor is the chemotherapy agent, mitoxantrone (mitox). We performed a series of studies to assess the impact of mitox on ven-R LSCs. Our findings demonstrate that venetoclax resistant LSCs are exquisitely sensitive to mitox. In CFU assays, doses as low 1.0nM show strong inhibitory activity. Further, treatment of immune deficient mice bearing human xenografts (Fig 2), showed significant reduction of bulk disease in primary mice, and strong suppression of LSCs in secondary transplants. Notably, DNA damage was not present in LSCs treated with mitox as measured by gamma H2AX staining. Additionally, parallel studies with the related agents, doxorubicin and etoposide, showed no inhibition of CFU, mitochondrial calcium, or OXPHOS activity. Lastly, no discernable effect on normal hematopoietic stem cell activity was evident. Conclusions Our findings suggest that ven-R LSCs have adapted to their unique cellular demands by increasing basal mitochondrial calcium levels to drive OXPHOS. Based on this finding, we propose that inhibition of mitochondrial calcium uptake impairs multiple enzymes required for OXPHOS, which in turns leads to eradication of LSCs. Importantly, we also show that the well-established chemotherapy agent mitoxantrone can effectively inhibit MCU at nanomolar concentrations and is a highly potent against ven-R LSCs. We are currently working to establish a clinical trial in which low-dose mitox will be deployed to augment ven-based therapy.

Effect of Tryptophane on Synthesis of Certain Exometabolites by Bacteria of Genus Acinetobacter, Nocardia, and Rhodococcus and Their Properties

The efficiency of integrated microbial biotechnologies for obtaining several practically valuable metabolites in one technological process is determined both by the maximum concentration of these substances and their properties. This is especially true for secondary metabolites, the composition and properties of which vary depending on the cultivation conditions of the producer. Aim. To research the effect of tryptophan (a precursor of auxin biosynthesis) in the culture media on the synthesis of certain exometabolites by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241, and Nocardia vaccinii IMV B-7405 as well as their properties. Methods. R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-724, and N. vaccinii IMV B-7405 were cultivated in a medium containing refined and waste sunflower oil, biodiesel waste, or ethanol as a carbon source. The concentration of tryptophan in the medium was 300 mg/L. Surfactants were extracted from the supernatant of the cultural liquid with a modified Folch mixture. Phytohormones were isolated from the supernatant by sequential extraction with organic solvents after surfactant extraction. Thin-layer chromatography was used for preliminary purification and concentration of phytohormones. Qualitative and quantitative determination of auxins was performed using high-performance liquid chromatography. The antimicrobial activity of surfactants was analysed by the minimum inhibitory concentration. The activity of enzymes of surface-active glycoand aminolipids biosynthesis (phosphoenolpyruvate synthetase, phosphoenolcarboxykinase, and NADP+-dependent glutamate dehydrogenase) was determined spectrophotometrically during the oxidation of NADH or NADP. Results. It was found that the presence of tryptophan in the culture medium of the strains under study did not affect the number of synthesized surfactants, which was 1.80−1.90, 1.55−1.75, and 1.50−1.65 g/L, respectively. At the same time, cultivation of R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-724, and N. vaccinii IMV B-7405 in the media with tryptophan increased the number of phytohormones: it was higher than the amount of phytohormones synthesized during cultivation without a precursor. The introduction of tryptophan into the culture medium of the strains was accompanied by the formation of surfactants. These compounds showed 2−4 times higher antimicrobial activity against the phytopathogenic bacteria (Agrobacterium tumefaciens UCM B-1000, Pseudomonas syringae UCM B-1027T, Xanthomonas vesicatoria UCM B-1106, Pectobacterium carotovorum UCM B-1075T, Clavibacter michiganensis IMV B-102 and Pseudomonas syringae pv. tomato IMV B-9167) than compounds synthesized on a medium without a precursor. The antimicrobial activity of surfactants synthesized by A. calcoaceticus IMV B-7241 in the presence of tryptophan either did not change compared to that for surfactants obtained without tryptophan, or increased slightly. Data on the activity of surfactant biosynthesis enzymes correlated with the indicators of their antimicrobial activity. In the presence of tryptophan in the culture medium of N. vaccinii IMV B-7405 and R. erythropolis IMV Ac-5017, NADP+-dependent glutamate dehydrogenase activity in the cells of these strains (a key enzyme for biosynthesis of aminolipids responsible for antimicrobial activity) increased almost by 1.4 times compared to that on a tryptophan-free medium. Conclusions. As a result of this work, it was found that the presence of tryptophan in the culture medium of researched strains did not affect the number of surfactants. The antimicrobial activity of surfactants against phytopathogenic bacteria either increased or remained unchanged compared to that established for surfactants synthesized without a precursor of auxin biosynthesis. The obtained data testify to the high efficiency of the potential use of surfactants complex preparations and phytohormones in crop production to stimulate the growth of plants and biocontrol of phytopathogenic bacteria.

Lymphocytes enzymatic status and peripheral blood neutrophils oxygen-dependent metabolism in patients with renal cancer

The immune system, one of the most important homeostatic organism systems, is actively involved in the protection against malignant tumors. The earliest sighs of immune homeostasis disorders should be invetigated at the cellular level, because of cell functional manifestations depend on the state of intracellular metabolic reactions. The study of lymphocyte NAD(P)-dependent dehydrogenases activity and peripheral blood neutrophils oxygen-dependent metabolism in patients with renal cellular carcinoma (RCC) showed a decrease in the intensity of ribose-5-phosphate and NADH-dependent synthetic processes, inhibition of terminal reactions of glycolysis. Altered activities of the studied enzymes favor an increase in outflow of intermediates of the Krebs cycle on the reaction of amino acid metabolism in peripheral blood lymphocytes. Radical nephrectomy was accompanied by increased activity of glycolysis. The basal level chemiluminescent of peripheral neutrophils of RCC patients response was higher both before and after operations. Stimulation of neutrophils by opsonized zymosan in vitro leads to increase in oxidative metabolism activity, most in 14 days after surgery period. Before and 30 days after surgery, adaptive metabolic capabilities of neutrophilic granulocytes decreased.

Synthesis and Biological Activity of Acinetobacter calcoaceticus IMV B-7241 Surfactants Depending on Monovalent Cations Content in Cultivation Medium

Microbial surfactants (biosurfactants) are multifunctional preparations due to a combination of physicochemical (reduction of surface and interfacial tension, emulsifying activity) and biological (antimicrobial and antiadhesive activity, the ability to destroy biofilms) properties. However, the disadvantage of biosurfactants synthesized as a complex of compounds is the possibility of changing the biological activity depending on the conditions of producer cultivation. Aim. To study the effect of potassium and sodium cations on the NADP+-dependent glutamate dehydrogenase activity of cell-free extract of Acinetobacter calcoaceticus ІМV B-7241 with subsequent appropriate modification of the nutrient medium composition and determination of antimicrobial and anti-adhesive activity of surfactant synthesized. Methods. A. calcoaceticus ІМV B-7241 strain was grown in media containing 2% of sunflower oil waste as a carbon source, as well as various concentrations of potassium and sodium chloride (basal – 1.0 g/l NaCl, medium #1 that did not contains NaCl, medium #2 in which the concentration of NaCl was 2.0 g/l, medium #3 in which the concentration of NaCl and KCl was 1.0 g/l each). The surfactants were extracted from the supernatant liquid culture with a modified Folch mixture. Antiadhesive activity and the degree of biofilms degradation were determined by spectrophotometric method, antimicrobial activity − by the indicator of the minimum inhibitory concentration (MIC). Activity of enzymes of surface-active aminolipids biosynthesis (NADP+-dependent glutamate dehydrogenase) and glycolipids (phosphoenolpyruvate (PEP) carboxylase, PEP-synthetase, PEP-carboxykinase, trehalose phosphate synthase) were analyzed in cell-free extracts obtained after the destruction of cells by ultrasound. Results. It was found that potassium and sodium cations in concentrations of 50 and 100 mM are inhibitors of NADP+-dependent glutamate dehydrogenase, and in lower concentrations (5–20 mM) – activators of this enzyme, as well as PEP-carboxykinase and PEP-synthetase. The increase in the biosurfactant concentration to 6.1−7.7 g/l during cultivation of A. calcoaceticus ІМV B-7241 in medium #1 and #3 was due to the predominant synthesis of glycolipids under such conditions, which was evidenced by the increase in 1.8−6.5 times in the activity of PEP-carboxylase, PEP-carboxykinase, PEP-synthetase and trehalose phosphate synthetase compared to the indicators on the basal medium. The concentration of surfactants synthesized in the basal medium was 3.6 g/l, but such surfactants were characterized by the highest antimicrobial and anti-adhesive activity. Their MIC against the test-cultures of studied bacteria (Pseudomonas sp. MI-2, Bacillus subtilis BT-2, Escherichia coli IEM-1, Staphylococcus aureus BMS-1, Enterobacter cloaceae C-8) and fungi (Candida albicans D-6, Rhizopus nigricans P1, Aspergillus niger P-3, Fusarium culmorum T-7) were 0.88−56 μg/ml and were by 2−3 orders of magnitude lower compared to established for surfactants synthesized in modified media #1–3. In the case of treatment of abiotic materials with surfactant solutions obtained on the basal medium, the adhesion of bacteria and fungi was on average 10–20% lower than after surface treatment by the surfactant synthesized in modified media. In the presence of 148−296 μg/ml of surfactants obtained in the basal medium, destruction of S. aureus BMS-1 and B. subtilis BT-2 biofilms was 45−66%, and C. albicans D-6 yeast – 39−44%. Under the action of similar concentrations of surfactants synthesized in modified media, the destruction of bacterial and yeast biofilms was lower: 6-52 and 20–46%, respectively. Conclusions. The obtained results are consistent with the data of our previous studies on the possibility of regulating the antimicrobial and antiadhesive activity of surfactants in the process of producer cultivation by changing the content of cations in the medium, which are inhibitors/activators of enzymes responsible for the synthesis of components of the surfactants complex, which have certain biological properties.

Neuronal cell-based high-throughput screen for enhancers of mitochondrial function reveals luteolin as a modulator of mitochondria-endoplasmic reticulum coupling

BackgroundMitochondrial dysfunction is a common feature of aging, neurodegeneration, and metabolic diseases. Hence, mitotherapeutics may be valuable disease modifiers for a large number of conditions. In this study, we have set up a large-scale screening platform for mitochondrial-based modulators with promising therapeutic potential.ResultsUsing differentiated human neuroblastoma cells, we screened 1200 FDA-approved compounds and identified 61 molecules that significantly increased cellular ATP without any cytotoxic effect. Following dose response curve-dependent selection, we identified the flavonoid luteolin as a primary hit. Further validation in neuronal models indicated that luteolin increased mitochondrial respiration in primary neurons, despite not affecting mitochondrial mass, structure, or mitochondria-derived reactive oxygen species. However, we found that luteolin increased contacts between mitochondria and endoplasmic reticulum (ER), contributing to increased mitochondrial calcium (Ca2+) and Ca2+-dependent pyruvate dehydrogenase activity. This signaling pathway likely contributed to the observed effect of luteolin on enhanced mitochondrial complexes I and II activities. Importantly, we observed that increased mitochondrial functions were dependent on the activity of ER Ca2+-releasing channels inositol 1,4,5-trisphosphate receptors (IP3Rs) both in neurons and in isolated synaptosomes. Additionally, luteolin treatment improved mitochondrial and locomotory activities in primary neurons and Caenorhabditis elegans expressing an expanded polyglutamine tract of the huntingtin protein.ConclusionWe provide a new screening platform for drug discovery validated in vitro and ex vivo. In addition, we describe a novel mechanism through which luteolin modulates mitochondrial activity in neuronal models with potential therapeutic validity for treatment of a variety of human diseases.

Characterization of aldo-keto reductase 1C subfamily members encoded in two rat genes (akr1c19 and RGD1564865). Relationship to 9-hydroxyprostaglandin dehydrogenase

Rat genes, akr1c19 and RGD1564865, encode members (R1C19 and 20HSDL, respectively) of the aldo-keto reductase (AKR) 1C subfamily, whose functions, however, remain unknown. Here, we show that recombinant R1C19 and 20HSDL exhibit NAD+-dependent dehydrogenase activity for prostaglandins (PGs) with 9α-hydroxy group (PGF2α, its 13,14-dihydro- and 15-keto derivatives, 9α,11β-PGF2 and PGD2). 20HSDL oxidized the PGs with much lower Km (0.3–14 μM) and higher kcat/Km values (0.064–2.6 min−1μM−1) than those of R1C19. They also differed in other properties: R1C19, but not 20HSDL, oxidized some 17β-hydroxysteroids (5β-androstane-3α,17β-diol and 5β-androstan-17β-ol-3-one). 20HSDL was specifically inhibited by zomepirac, but not by R1C19-selective inhibitors (hexestrol, flavonoids, ibuprofen and flufenamic acid), although the two enzymes were sensitive to indomethacin and cis-unsaturated fatty acids. The mRNA for 20HSDL was expressed abundantly in rat kidney and at low levels in the liver, testis, brain, heart and colon, in contrast to ubiquitous expression of R1C19 mRNA. The comparison of enzymic features of R1C19 and 20HSDL with rat PG dehydrogenases and other AKRs suggests not only a close relationship of 20HSDL with 9-hydroxy-PG dehydrogenase in rat kidney, but also roles of R1C19 and rat AKRs (1C16 and 1C24) in the metabolism of PGF2α, PGD2 and 9α,11β-PGF2 in other tissues.

OR03-06 NAD+ Availability Modulates 11β-HSD1-Mediated Glucocorticoid Regeneration in Mouse Skeletal Muscle

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an NADPH-dependant reductase located in the sarcoplasmic reticulum (SR) lumen of skeletal muscle. It generates active glucocorticoids to regulate permissive and adaptive metabolism and contributes to the development of the Cushing’s syndrome phenotype in mice receiving oral corticosterone. The SR enzyme hexose-6-phosphate dehydrogenase (H6PDH) generates NADPH which supports 11β-HSD1 activity. H6PDH depletion disrupts the SR NADPH/NADP ratio leading 11β-HSD1 to assume glucocorticoid-inactivating dehydrogenase activity. Little is understood regarding routes to NAD(P)(H) biosynthesis and metabolism in the SR. Here we asked whether modulating cellular nicotinamide adenine dinucleotide (NAD+) availability (the parent molecule of NAD(P)(H)) would influence muscle 11β-HSD1 activity given its sensitivity to the SR NADPH/NADP ratio. We used FK866 to inhibit nicotinamide phospho-ribosyltransferase (NAMPT, rate-limiting enzyme in NAD+ biosynthesis) to deplete NAD(P)(H) in wild type mouse primary myotubes. FK866 treatment for 48h impaired cellular energetic status, reducing NAD+ (>90%), NADP+ (>50%) and ATP (>30%) without limiting cell viability. 11β-HSD1 reductase activity was decreased to 30% that of untreated cells (152±18 vs. 512±44 pmol/mg protein/h respectively, p<0.005). Employing H6PD knockout myotubes, NADP+-dependent 11β-HSD1 dehydrogenase activity was also impaired following NAMPT inhibition. The NAD+ precursor nicotinamide riboside (NR, 0.5mM), which bypasses NAMPT inhibition through the NR kinase pathway restored NAD+ levels and rapidly rescued 11β-HSD1 reductase activity in wild type and dehydrogenase activity in H6PD knockout myotubes. To assess this in vivo, we examined 11β-HSD1 reductase activity in muscle explants of inducible muscle-specific NAMPT knockout mice in which NAD+ levels are reduced by 90%, and show 40% lower activity compared to wild type explants (114±14 vs. 67±10 pmol/mg protein/h, p=0.04). These data suggest a novel level of redox-regulated 11β-HSD1-mediated glucocorticoid metabolism in skeletal muscle. These data also imply a pathway by which NAD+ status is communicated between the cytosol and the SR, which is contrary to the current belief that the pyridine nucleotide pool in these compartments is separate. NAMPT inhibition is being studied as a potential anti-cancer therapy and these data reveal hitherto unanticipated effects this therapy may have in a range of tissues.

Pathways of 4-Hydroxy-2-Nonenal Detoxification in a Human Astrocytoma Cell Line.

One of the consequences of the increased level of oxidative stress that often characterizes the cancer cell environment is the abnormal generation of lipid peroxidation products, above all 4-hydroxynonenal. The contribution of this aldehyde to the pathogenesis of several diseases is well known. In this study, we characterized the ADF astrocytoma cell line both in terms of its pattern of enzymatic activities devoted to 4-hydroxynonenal removal and its resistance to oxidative stress induced by exposure to hydrogen peroxide. A comparison with lens cell lines, which, due to the ocular function, are normally exposed to oxidative conditions is reported. Our results show that, overall, ADF cells counteract oxidative stress conditions better than normal cells, thus confirming the redox adaptation demonstrated for several cancer cells. In addition, the markedly high level of NADP+-dependent dehydrogenase activity acting on the glutahionyl-hydroxynonanal adduct detected in ADF cells may promote, at the same time, the detoxification and recovery of cell-reducing power in these cells.

Metabolic changes in peripheral blood lymphocytes from children with recurrent respiratory infections

Objective: to examine activity and correlative relations for peripheral blood lymphocyte NAD (P)-dependent dehydrogenases in young children with recurrent respiratory infections with hypertrophy of the pharyngeal tonsils and bronchial obstructive syndrome. Methods. 89 children, aged 1–3 years, with recurrent respiratory infections were examined, including 35 children with hypertrophy of pharyngeal tonsils (HPT) and 54 children — with bronchial obstructive syndrome (BOS). Control group contained 20 age-matched healthy children. Activity and relations for peripheral blood lymphocyte for NAD(P)-dependent dehydrogenases were assessed by using bioluminescent method proposed by А.А. Savchenko and L.N. Suntsova (1989). Results. It was found that children with recurrent respiratory infections displayed altered enzyme status in peripheral blood lymphocytes. In particular, activity ribose-5-phosphate- and NAD(P)-dependent metabolic events as well as substrate flux via the tricarboxylic acid cycle were elevated that was paralleled with decreased lactate dehydrogenase anaerobic reaction, thereby implicating a role for malate-aspartate shunt in the energy turnover, substrate efflux from the tricarboxylic acid cycle into amino acid metabolic pathways as well as activity of glutathione reductase. Moreover, features of altered enzymatic profile in peripheral blood lymphocytes were uncovered, which depended on type of complication related to respiratory infection. In addition, children with hypertrophy of pharyngeal tonsils were featured with increased influx of lipid catabolism products into glycolysis, elevated level of malic enzyme activity and decreased pyruvate production. However, children with bronchial obstructive syndrome were found to have decreased glycerol-3-phosphate dehydrogenase activity resulting in lowered shunting activity of slow reactions in Krebs cycle and increased influx of amino acid metabolism intermediates into the tricarboxylic acid cycle. Reshaping of enzymatic profile in peripheral blood lymphocytes depended on type of complications coupled to respiratory infections (ENT-pathology or BOS syndrome). A correlation analysis revealed features of relationship between parameters of NAD(P)-dependent dehydrogenase activity in peripheral blood lymphocytes found in children with hypertrophy of pharyngeal tonsils and bronchial obstructive syndrome marked by quantity, modality and power of correlative links. Conclusion. Children with the recurrent respiratory infections require metabolic therapy aimed at restoring intracellular pathology-driven metabolic processes in immune cells.

Two-step d-ononitol epimerization pathway in Medicago truncatula.

Methylated inositol, d-pinitol (3-O-methyl-d-chiro-inositol), is a common constituent in legumes. It is synthesized from myo-inositol in two reactions: the first reaction, catalyzed by myo-inositol-O-methyltransferase (IMT), consists of a transfer of a methyl group from S-adenosylmethionine to myo-inositol with the formation of d-ononitol, while the second reaction, catalyzed by d-ononitol epimerase (OEP), involves epimerization of d-ononitol to d-pinitol. To identify the genes involved in d-pinitol biosynthesis in a model legume Medicago truncatula, we conducted a BLAST search on its genome using soybean IMT cDNA as a query and found putative IMT (MtIMT) gene. Subsequent co-expression analysis performed on publicly available microarray data revealed two potential OEP genes: MtOEPA, encoding an aldo-keto reductase and MtOEPB, encoding a short-chain dehydrogenase. cDNAs of all three genes were cloned and expressed as recombinant proteins in E.coli. In vitro assays confirmed that putative MtIMT enzyme catalyzes methylation of myo-inositol to d-ononitol and showed that MtOEPA enzyme has NAD+ -dependent d-ononitol dehydrogenase activity, while MtOEPB enzyme has NADP+ -dependent d-pinitol dehydrogenase activity. Both enzymes are required for epimerization of d-ononitol to d-pinitol, which occurs in the presence of NAD+ and NADPH. Introduction of MtIMT, MtOEPA, and MtOEPB genes into tobacco plants resulted in production of d-ononitol and d-pinitol in transformants. As this two-step pathway of d-ononitol epimerization is coupled with a transfer of reducing equivalents from NADPH to NAD+ , we speculate that one of the functions of this pathway might be regeneration of NADP+ during drought stress.

Metabolic support of the respiratory burst in blood and sputum neutrophils of patients with community-acquired pneumonia

The aim of the study was to investigate relationships between the respiratory burst in blood and sputum neutrophils and intracellular enzyme activity in patients with pneumonia. Methods. The study involved 82 patients with moderate to severe community-acquired pneumonia (CAP). The chemiluminescent assay was used to investigate synthesis of primary and secondary reactive oxygen species (ROS). The bioluminescent method was used to examine NAD(P)-dependent dehydrogenase activity in neutrophils. Results. Low-intensity respiratory burst in blood neutrophils and its predominant relations to the state of mitochondrial metabolism and malic enzyme activity were observed in healthy subjects. Blood neutrophils in patients with CAP were activated; the anaerobic respiration and mitochondrial metabolism increased in the cells. Additionally, intensity of the respiratory burst was related to terminal glycolysis reactions and the key reaction of the pentose phosphate cycle. Sputum neutrophils in patients with CAP were also activated. Conclusion. Abnormalities of metabolic support of the respiratory burst, such as decreased production of primary and secondary ROS, could appear under unfavorable conditions. Peroxidation increased in the cells, the intensity of terminal glycolysis reactions decreased, and substrates transferred from the citric acid cycle to amino acid exchange reactions. Under these conditions, malic enzyme remained the only substrate that stimulated the respiratory burst in sputum neutrophils, while substrate transfer from the tricarboxylic acid cycle inhibited synthesis of the secondary ROS.

Alcohol dehydrogenase 1 participates in the Crabtree effect and connects fermentative and oxidative metabolism in the Zygomycete Mucor circinelloides.

Mucor circinelloides is a dimorphic Zygomycete fungus that produces ethanol under aerobic conditions in the presence of glucose, which indicates that it is a Crabtree-positive fungus. To determine the physiological role of the alcohol dehydrogenase (ADH) activity elicited under these conditions, we obtained and characterized an allyl alcohol-resistant mutant that was defective in ADH activity, and examined the effect of adh mutation on physiological parameters related to carbon and energy metabolism. Compared to the Adh+ strain R7B, the ADH-defective (Adh-) strain M5 was unable to grow under anaerobic conditions, exhibited a considerable reduction in ethanol production in aerobic cultures when incubated with glucose, had markedly reduced growth capacity in the presence of oxygen when ethanol was the sole carbon source, and exhibited very low levels of NAD+-dependent alcohol de-hydrogenase activity in the cytosolic fraction. Further characterization of the M5 strain showed that it contains a 10-bp deletion that interrupts the coding region of the adhl gene. Complementation with the wild-type allele adh1+ by transformation of M5 remedied all the defects caused by the adh1 mutation. These findings indicate that in M. circinelloides, the product of the adh1 gene mediates the Crabtree effect, and can act as either a fermentative or an oxidative enzyme, depending on the nutritional conditions, thereby participating in the association between fermentative and oxidative metabolism. It was found that the spores of M. circinelloides possess low mRNA levels of the ethanol assimilation genes (adl2 and acs2), which could explain their inability to grow in the alcohol.

The spatial metabolic heterogeneity of solid type of Ehrlich carcinoma

The NAD(P)-dependent dehydrogenase activity was studied in different fields of solid form of Ehrlich carcinoma. It was shown that there is a metabolic distinction between different fields of the solid tumor. In this way there is a significant difference between ascites and solid type of Ehrlich carcinoma.

The Spatial Metabolic Heterogeneity of Solid Type of Enrlich Carcinoma

In this work, we investigated the NAD(P)-dependent dehydrogenase activity in different fields of the solid form of Ehrlich carcinoma. It was shown that there is a metabolic distinction between different fields of the solid tumor. In this way, there is a significant difference between the ascites and solid type of Ehrlich carcinoma. In the central area of the tested sample of tumor tissue, there is a high intensity of energetic metabolism and biosynthetic processes as opposed to the peripheral areas. Previously, we proposed the concept of nonspecific metabolic reaction of the cell in organism upon the influence of negative factors. In accordance with this concept, our results indicate the development of adaptation in the tumor cells in the central area of the tested sample.

DEPENDENCE OF NEUTROPHIL RESPIRATORY BURST ON THEIR METABOLIC STATE IN THE PATIENTS WITH ACUTE DESTRUCTIVE PANCREATITIS OF DIFFERENT SEVERITY

The aim of the study was to investigate a dependence of respiratory burst state in neutrophils on activities of their intracellular enzymes in patients with acute destructive pancreatitis (ADP) of different severity. The study included 50 patients with ADP of moderate (17 cases) and severe degree (33 cases). A group of 47 healthy people was examined as controls. The respiratory burst state was examined in neutrophilic granulocytes by means of chemiluminescence assays. A study of NAD(P)-dependent dehydrogenases activity in blood neutrophils was performed using bioluminescent analysis. We have revealed that a decrease in spontaneous and induced synthesis of superoxide radical by neutrophils was detected in ADP patients, independently of the disease severity. Kinetics of primary ROS synthesis was also impaired in patients with severe ADP. In patients with moderate disorder, the level of secondary ROS synthesis by neutrophils proved to be increased, whereas, in cases of severe disease, a disturbed kinetics of secondary ROS synthesis by neutrophils was detected at a resting state, showing increased synthetic level upon additional induction by zymosan. Metabolism of neutrophils in patients with ADP is characterized by activation of plastic processes (due to the products of the pentose phosphate cycle) and aerobic energy (increased substrate flow intensity in the cycle of tricarboxylic acids). However, NADPH neutrophilic pool in patients with moderate disorder could be additionally supported by enzymatic malic enzyme reactions and NADP-dependent glutamate dehydrogenase. Activation of peroxidation events in patients with severe ADP is revealed, which needs NADPH compensation. The state of energy processes in blood neutrophils in patients with ADP is characterized by lacking changes in glycolytic activity, and increased intensity of substrate flux along tricarboxylic acids cycle. Activity of aerobic processes in patients with moderate disease is maintained by the products of amino acid metabolism (via glutamate dehydrogenase), whereas, in severe ADP it may be provided by products of lipid catabolism. Using correlation analysis, a dependence of respiratory burst of neutrophils on the state of their metabolism was studied. We have found that intensity and kinetics of respiratory burst in the neutrophils of controls depends only on the activity of NADP-dependent dehydrogenases. The changes in cellular metabolic activity in the patients with moderate ADP led to disturbances of their regulatory effect upon the state of neutrophil respiratory burst. In patients with severe disorder, the degree a neutrophil respiratory burst is stimulated by reductive amination of α-ketoglutarate, being, however, inhibited by intracellular peroxidation processes.

FEATURES OF THE PHENOTYPE AND NAD(P)-DEPENDENT DEHYDROGENASES ACTIVITY IN NEUTROPHIL BY PATIENTS WITH WIDESPREAD PURULENT PERITONITIS IN PROGNOSIS FOR SEPSIS DEVELOPMENT

The aim of the study was to examine the features of phenotype and the levels of NAD(P)-dependent dehydrogenases activity of blood neutrophils in the prognosis of abdominal sepsis development in patients with widespread purulent peritonitis (WPP). 50 patients with WPP of community and hospital origin in the pre-operative period were examined. From the 5th to the 10th day of the postoperative period 35 patients (70%) had developed abdominal sepsis, 15 patients (30%) had absence of complications. As controls 67 respect healthy people were examined. The research blood neutrophils phenotype was performed by f low cytometry using a direct immunofluorescence whole peripheral blood. The levels of surface receptor expression was assessed by the mean fluorescence intensity. The NAD(P)-dependent dehydrogenases activity in the blood neutrophils studied using bioluminescence method. It was established that the inflammatory reaction in patients with WPP is characterized by neutrophilia and changes in the phenotype of blood neutrophils. The markers of the subsequent development of sepsis in WPP are less pronounced (in comparison with the indices of uncomplicated patients), an increase in the number of neutrophils, a decrease in the HLA-DR + -cell count against the background of a high level of neutrophils expressing a high affinity receptor for IgG. The patients without subsequent complications had the number of neutrophils with CD23 receptor expression is increased. Metabolism of neutrophils in patients with WPP is characterized by a decrease in the intensity of plastic processes due to low activity of glucose-6-phosphate dehydrogenase and an imbalance in the activity of the enzymes of the mitochondrial compartment. A feature of the neutrophil metabolism in patients with WPP without subsequent development of sepsis is a high activity of anaerobic lactate dehydrogenase reaction and a decrease in the activity of NADP-dependent decarboxylating malate dehydrogenase. The patients with WPP with subsequent development of sepsis had a high level of NAD-dependent out flow of substrates from the tricarboxylic acid cycle on the amino acid exchange reaction via glutamate dehydrogenase which can affect the activity of aerobic respiration of blood neutrophils. The established differences in the phenotype and activity of enzymes in the blood neutrophils in patients with WPP depending on the subsequent development of sepsis determine the possibility of creating a method for predicting the development of complications and developing immunoactive therapy in the postoperative period of WPP.

NADP+-dependent isocitrate dehydrogenase activity in marine plankton

Abstract NADP+ -isocitrate dehydrogenase (NADP-IDH), as one of the most active intracellular CO 2 -producing enzymes, was measured in marine plankton by adapting an enzyme assay to the 0.7–50 μm, 50–200 μm, and 200–2000 μm size fraction of the Canary Islands coastal plankton community. The variability of NADP-IDH activity in relation to pH, temperature, dilution of the sample, centrifugation or substrates was measured. In our hands, the maximum NADP-IDH activity (V max) in marine plankton samples was attained in 0.1 M phosphate buffer at pH 8.2 (pKa1 = 7.6 and pKa2 = 8.8), by adding 6 mM MgCl2, 0.3 mM NADP+ and 2 mM DL-trisodium isocitrate. The optimum temperature in these subtropic mesozooplankton samples was 28 °C, with an Arrhenius energy of activation (Ea) of 20.4 kcal mol−1 (85.4 J mol−1), and an Arrhenius collision frecuency factor (A) of 2.9·1011 mol NADPH s−1 (kg of protein)−1. The apparent Michaelis-Menten Km values for the substrates in crude homogenates at pH 8.5 and 18 °C were 271 ± 63 μM for isocitrate and 18 ± 3 μM for NADP+. This enzyme, in addition to its high CO2-producing activity, is also important in regulating other CO2 -producing enzymes. Thus, it can be used to calculate: (1) respiration in marine samples; (2) carbon flux in the water column; (3) metabolic adaptations to environmental changes; (4) roles of the plankton components of the food chain; and (5) the reactive oxygen species (ROS) scavenging capacity of the marine plankton resources.

Decrease in the cytosolic NADP+-dependent isocitrate dehydrogenase activity through porcine sperm capacitation

In order to understand the molecular mechanisms involved in the sperm capacitation, we have identified the proteins tyrosine-phosphorylated during the capacitation especially in conjunction with the regulation of the levels of reactive oxygen species (ROS) in sperm. In the present study, the effects of the tyrosine phosphorylation of cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) on its catalytic activity and on the levels of ROS in sperm have been studied. The tyrosine phosphorylated IDPc showed a significantly lowered enzymatic activity. The immunocytochemical analyses using the highly specific antisera against IDPc revealed that IDPc was mainly localized to the principal piece of the porcine sperm flagellum. As IDPc is one of the major NADPH regenerating enzymes in porcine sperm, it is strongly suggested that the decrease in IDPc activity is involved in the increased levels of ROS, which results in the induction of hyperactivated flagellar movement and capacitation.