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1.
Acta Naturae ; 14(4): 84-93, 2022.
Article in English | MEDLINE | ID: mdl-36694905

ABSTRACT

The regulatory functions of the B-cell compartment play an important role in the development and suppression of the immune response. Disruption of their anti-inflammatory functions may lead to the acceleration of immunopathological processes, and to autoimmune diseases, in particular. Unfortunately, the exact mechanism underlying the functioning and development of regulatory B cells (Breg) has not yet been fully elucidated. Almost nothing is known about their specificity and the structure of their B-cell receptors (BCRs). In this research, we analyzed the BCR repertoire of the transitional Breg (tBreg) subpopulation with the CD19+CD24highCD38high phenotype in patients with multiple sclerosis (MS), using next-generation sequencing (NGS). We show, for the first time, that the immunoglobulin germline distribution in the tBreg subpopulation is different between MS patients and healthy donors. The registered variation was more significant in patients with a more severe form of the disease, highly active MS (HAMS), compared to those with benign MS (BMS). Our data suggest that during MS development, deviations in the immunoglobulin Breg repertoire occur already at the early stage of B-cell maturation, namely at the stage of tBregs: between immature B cells in the bone marrow and mature peripheral B cells.

2.
Georgian Med News ; (311): 68-73, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33814394

ABSTRACT

The aim - in the given research, the difficulties in interpreting the study results of oxidative homeostasis of oral fluid are analyzed. Changes in the total antioxidant activity of blood and saliva can be multidirectional - an increase or decrease in the oral fluid indicator and a reduction in the parameter of blood plasma can be recorded. To resolve the emerging difficulties, there was proposed a parallel assessment of the dynamics of changes in the total antioxidant activity of blood plasma and oral fluid in the patients of 4 groups with nosological forms of fundamentally different in the distribution and localization of the pathological process, which include: phlegmons of the maxillofacial region, partial absence of teeth, type 2 diabetes mellitus and the pelvic inflammatory diseases. As a result of the conducted studies, it was shown that a simultaneous decrease in the total antioxidant activity of blood plasma and oral fluid was attributable to the chronic long-term somatic diseases of a systemic character with a significant metabolic disorder, such as type 2 diabetes mellitus. A decrease in the total antioxidant activity of blood plasma and the unchanged oral fluid index was characteristic of somatic diseases of limited prevalence without affection of the maxillofacial region's tissues. In our case, such an example was a chronic inflammatory disease of the uterus with a combined course of bilateral salpingoophoritis. An increase in the oral fluid's total antioxidant activity on the background of a normal or even slightly reduced level of the antioxidant potential of blood plasma was characteristic of dental diseases. The latter situation was most likely for the dental profile diseases, in which damage to the oral tissues can provoke the leaching of cellular contents, including endogenous antioxidants or other components of regenerative activity in the oral fluid. Herein, changes in the antioxidant activity of blood plasma may reflect the prevalence of a pathological process at the systemic level or its limitation only to the dentoalveolar system's tissues and elements. As an example of such a situation, the patients with phlegmon of the maxillofacial region or patients with partial absence of teeth can be cited.


Subject(s)
Antioxidants , Diabetes Mellitus, Type 2 , Female , Humans , Oxidation-Reduction , Oxidative Stress , Saliva
3.
Biochemistry (Mosc) ; 85(5): 553-566, 2020 May.
Article in English | MEDLINE | ID: mdl-32571185

ABSTRACT

Inactivated (whole-virion, split, subunit, and adjuvanted) vaccines and live attenuated vaccine were tested in parallel to compare their immunogenicity and protective efficacy. Homologous and heterosubtypic protection against the challenge with influenza H5N1 and H1N1 viruses in a mouse model were studied. Single immunization with live or inactivated whole-virion H5N1 vaccine elicited a high level of serum antibodies and provided complete protection against the challenge with the lethal A/Chicken/Kurgan/3/05 (H5N1) virus, whereas application of a single dose of the split vaccine was much less effective. Adjuvants increased the antibody levels. Addition of the Iso-SANP adjuvant to the split vaccine led to a paradoxical outcome: it increased the antibody levels but reduced the protective effect of the vaccine. All tested adjuvants shifted the ratio between IgG1 and IgG2a antibodies. Immunization with any of the tested heterosubtypic live viruses provided partial protection against the H5N1 challenge and significantly reduced mouse mortality, while inactivated H1N1 vaccine offered no protection at all. More severe course of illness and earlier death were observed in mice after immunization with adjuvanted subunit vaccines followed by the challenge with the heterosubtypic virus compared to challenged unvaccinated animals.


Subject(s)
Immunity , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H5N1 Subtype/immunology , Influenza Vaccines/pharmacology , Influenza, Human/immunology , Influenza, Human/prevention & control , Vaccines, Inactivated/immunology , Adjuvants, Immunologic/pharmacology , Animals , Humans , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza, Human/virology , Mice , Mice, Inbred BALB C , Vaccination
4.
Stomatologiia (Mosk) ; 98(4): 89-92, 2019.
Article in Russian | MEDLINE | ID: mdl-31513157

ABSTRACT

The aim of the study was to determine the relationship between the background on-life drug therapy of psychoneurological disorders with dental pathology in children by analyzing the characteristics of pharmacotherapy and the physical characteristics of the oral fluid. The study involved 277 children with psychoneurological disorders and 270 children without comorbid pathology. The deterioration of the physical characteristics of the oral fluid in children with psychoneurological pathology associated with the experience of comorbid disease and drug therapy for the comorbid background has been established.


Subject(s)
Mental Disorders/complications , Mouth Diseases , Nervous System Diseases , Child , Humans , Mouth Diseases/psychology , Nervous System Diseases/complications
5.
Stomatologiia (Mosk) ; 96(6): 4-8, 2017.
Article in Russian | MEDLINE | ID: mdl-29260756

ABSTRACT

The aim of the study was to assess histochemical changes of the dental pulp in direct pulp capping/experimental osteoporosis animal model. The study was performed on 20 two-year sheep with simulated acute pulpitis divided in 2 groups: main (15 animals/120 teeth) and control (5 animals/40 teeth). Direct pulp capping in the main group included tissue-engineered structure composed of a hydrogel PuraMatrix/3DM with ectomesenchymal stem cells immobilized on collagen sponge. In the control group collagen sponges with hydrocortisone furatsilin, chondroitin sulfate, аnaesthesinum were used for the same purpose. Dentinal bridge formation was much slower in controls than in the main group. Developed tissue-engineered design optimizes each stage of the healing process by protecting the pulp from infection, reduction of exudation, hemostatic effect and in long term contributes to a significant acceleration of the formation of the dentinal bridge.


Subject(s)
Biological Therapy/methods , Collagen/administration & dosage , Dental Pulp Capping/methods , Dental Pulp/pathology , Dental Pulp/physiology , Dentinogenesis , Osteoporosis/complications , Pulpitis/therapy , Animals , Disease Models, Animal , Hydrocortisone/administration & dosage , Pulpitis/complications , Pulpitis/pathology , Sheep , Treatment Outcome
6.
Mol Biol (Mosk) ; 51(6): 1008-1023, 2017.
Article in Russian | MEDLINE | ID: mdl-29271964

ABSTRACT

Immunotherapy is one of the most rapidly progressing and promising fields in antitumor therapy. It is based on the idea of using immune cells of patient or healthy donors for elimination of malignant cells. T lymphocytes play a key role in cell-mediated immunity including the response to tumors. Recently developed approaches of altering antigen specificity of T cells consist of their genetic modification (introduction of additional T cell receptor or chimeric antigen receptor), as well as the use of bispecific molecules that crosslink target and effector cells. These approaches are used to retarget T lymphocytes with arbitrary specificity against tumor antigens in the context of antitumor immunotherapy. The high potential of T cell immunotherapy was demonstrated in a number of clinical trials. In the future, it is possible to develop approaches to the therapy of a wide spectrum of tumors. The selection of the optimal antigen is the main challenge in successful T cell immunotherapy, as it largely determines the effectiveness of the treatment, as well as the risk of side effects. In this review we discuss potential methods of modification of T cell specificity and targets for immunotherapy.


Subject(s)
Antigens, Neoplasm/immunology , Immunotherapy/methods , Mutant Chimeric Proteins/immunology , Neoplasms/therapy , Receptors, Antigen, T-Cell/immunology , T-Lymphocytes, Cytotoxic/immunology , Antibodies, Bispecific/biosynthesis , Antibodies, Bispecific/pharmacology , Antigens, Neoplasm/chemistry , Antigens, Neoplasm/genetics , Cell Engineering , Cytotoxicity, Immunologic , Gene Expression , Humans , Mutant Chimeric Proteins/chemistry , Mutant Chimeric Proteins/genetics , Neoplasms/genetics , Neoplasms/immunology , Neoplasms/pathology , Receptors, Antigen, T-Cell/chemistry , Receptors, Antigen, T-Cell/genetics , T-Lymphocytes, Cytotoxic/metabolism
7.
Geobiology ; 15(4): 588-616, 2017 07.
Article in English | MEDLINE | ID: mdl-28603844

ABSTRACT

Non-calcified marine macroalgae ("seaweeds") play a variety of key roles in the modern Earth system, and it is likely that they were also important players in the geological past, particularly during critical transitions such as the Cambrian Explosion (CE) and the Great Ordovician Biodiversification Event (GOBE). To investigate the morphology and ecology of seaweeds spanning the time frame from the CE through the GOBE, a carefully vetted database was constructed that includes taxonomic and morphometric information for non-calcified macroalgae from 69 fossil deposits. Analysis of the database shows a pattern of seaweed history that can be explained in terms of two floras: the Cambrian Flora and the Ordovician Flora. The Cambrian Flora was dominated by rather simple morphogroups, whereas the Ordovician Flora, which replaced the Cambrian Flora in the Ordovician and extended through the Silurian, mainly comprised comparatively complex morphogroups. In addition to morphogroup representation, the two floras show marked differences in taxonomic composition, morphospace occupation, functional-form group representation, and life habit, thereby pointing to significant morphological and ecological changes for seaweeds roughly concomitant with the GOBE and the transition from the Cambrian to Paleozoic Evolutionary Faunas. Macroalgal changes of a similar nature and magnitude, however, are not evident in concert with the CE, as the Cambrian Flora consists largely of forms established during the Ediacaran. The cause of such a lag in macroalgal morphological diversification remains unclear, but an intriguing possibility is that it signals a previously unknown difference between the CE and GOBE with regard to the introduction of novel grazing pressures. The consequences of the establishment of the Ordovician Flora for shallow marine ecosystems and Earth system dynamics remain to be explored in detail but could have been multifaceted and potentially include impacts on the global carbon cycle.


Subject(s)
Biodiversity , Biological Evolution , Fossils , Seaweed , Animals , Ecosystem
9.
Geobiology ; 15(4): 572-587, 2017 07.
Article in English | MEDLINE | ID: mdl-28397387

ABSTRACT

The Ediacara biota features the rise of macroscopic complex life immediately before the Cambrian explosion. One of the most abundant and widely distributed elements of the Ediacara biota is the discoidal fossil Aspidella, which is interpreted as a subsurface holdfast possibly anchoring a frondose epibenthic organism. It is a morphologically simple fossil preserved mainly in siliciclastic rocks, which are unsuitable for comprehensive stable isotope geochemical analyses to decipher its taphonomy and paleoecology. In this regard, three-dimensionally preserved Aspidella fossils from upper Ediacaran limestones of the Khatyspyt Formation in the Olenek Uplift of northern Siberia offer a rare opportunity to leverage geochemistry for insights into their taphonomy and paleoecology. To take advantage of this opportunity, we analyzed δ13 Ccarb , δ18 Ocarb , δ13 Corg , δ34 Spyr , and iron speciation of the Khatyspyt Aspidella fossils and surrounding sediment matrix in order to investigate whether they hosted microbial symbionts, how they were fossilized, and the redox conditions of their ecological environments. Aspidella holdfasts and surrounding sediment matrix show indistinguishable δ13 Corg values, suggesting they did not host and derive significant amount of nutrients from microbial symbionts such as methanogens, methylotrophs, or sulfide-oxidizing bacteria. δ13 Ccarb , δ18 Ocarb , and δ34 Spyr data, along with petrographic observations, suggest that microbial sulfate reduction facilitated the preservation of Aspidella by promoting early authigenic calcite cementation in the holdfasts before matrix cementation and sediment compaction. Iron speciation data are equivocal, largely because of the low total iron concentrations. However, consideration of published sulfur isotope and biomarker data suggests that Aspidella likely lived in non-euxinic waters. It is possible that Aspidella was an opportunistic organism, colonizing the seafloor in large numbers when paleoenvironments were favorable. This study demonstrates that geochemical data of Ediacaran fossils preserved in limestones can offer important insights into the taphonomy and paleoecology of these enigmatic organisms living on the eve of the Cambrian explosion.


Subject(s)
Calcium Carbonate/chemistry , Fossils , Geologic Sediments/chemistry , Animals , Biota , Oxidation-Reduction , Siberia
10.
Article in Russian | MEDLINE | ID: mdl-28091493

ABSTRACT

The research carried out in the framework of the health promotion programs for the children made it possible to obtain characteristics of the patients admitted to health promotion facilities, identify the risk factors for the development of acute respiratory diseases, and substantiate the principles of the differentiated approach to the rehabilitation of such patients based at the institutions of this type taking into consideration the health group to which a concrete patient is referred and the risk factors of acute respiratory diseases. The feasibility and effectiveness of the addition of aromatherapy and treatment with the use of polarized light into the health promotion programs for the children presenting with acute respiratory diseases that they develop during the period of adaptation based at health promotion institutions are discussed.


Subject(s)
Exercise Therapy , Health Promotion/methods , Physical Therapy Modalities , Pre-Exposure Prophylaxis/methods , Respiratory Tract Infections/prevention & control , Child , Female , Health Promotion/organization & administration , Humans , Male , Pre-Exposure Prophylaxis/organization & administration , Respiratory Tract Infections/rehabilitation , School Health Services
11.
Acta Naturae ; 5(4): 94-104, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24455188

ABSTRACT

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that primarily affects young and middle-aged people. It is widely accepted that B lymphocyte activation is required for MS progression. Despite the fact that the exact triggering mechanisms of MS remain enigmatic, one may suggest that MS can be induced by viral or bacterial infection in combination with specific genetic and environmental factors. Using deep sequencing and functional selection methodologies we characterized clones of poly- and cross-reactive antibodies that are capable of simultaneous recognition of viral proteins and autoantigens. The latter, in turn, possibly may trigger MS progression through molecular mimicry. It was identified that two cross-reactive antigens are probably recognized by light or heavy chains individually. According to the high structural homology between selected autoantibodies and a number of various antiviral IgGs, we suggest that a wide range of pathogens, instead of a single virus, be regarded as possible triggers of MS.

12.
Mol Biol (Mosk) ; 40(1): 25-30, 2006.
Article in Russian | MEDLINE | ID: mdl-16523688

ABSTRACT

Retrotransposon L1 codes for a unique dicistronic mRNA which serves both a transposition intermediate and a template for the synthesis of two proteins of this mobile element. According to preliminary data, the translation initiation of both cistrons of L1 occurs by non-canonical mechanisms. When translating the L1 mRNA in rabbit reticulocyte lysate (RRL), a standard system routinely used by many researchers to study mechanisms of translation initiation in eukaryotes, we observed along with expected products a number of polypeptides resulted from aberrant initiation at internal AUG codons. Such products are absent on translation of L1 mRNA in vivo. Addition to the system of a cytoplasmic extract from HeLa cells resulted in disappearance of these abberant products whereas the efficiency of translation of the first cistron remained unchanged. The level of translation of the second cistron became significantly lower. This also made the picture closer to that observed in vivo. These and other experiments allowed us to clearly demonstrate that the new combined cell-free system is much more adequate to study mechanisms of translation initiation than a regular RRL.


Subject(s)
Protein Biosynthesis , RNA, Messenger/genetics , Retroelements , Animals , Cell-Free System , Codon, Initiator , HeLa Cells , Humans , In Vitro Techniques , RNA, Messenger/physiology , Rabbits , Reticulocytes/metabolism , Retroelements/physiology
13.
Kardiologiia ; 45(7): 21-6, 2005.
Article in Russian | MEDLINE | ID: mdl-16091656

ABSTRACT

Mexicor (5% solution and capsules) was used in 40 of 80 conventionally treated patients with acute myocardial infarction. The drug was given intravenously for 5 days, than intramuscularly (6-9 mg/kg) for 9 days and orally (0.1 mg t.i.d.) thereafter until discharge. Severity of oxidative stress was evaluated by K coefficient. Calculation of this coefficient required data on degree of oxidation of lipids in blood serum, serum levels of diene conjugates, malonic dialdehyde, alpha-tocopherol and ceruloplasmin. These parameters as well as activity of superoxide dismutase, glutathione peroxidase and catalase in erythrocytes were measured at admission, on days 2, 3, 7, 14 and at discharge. Mexicor treated compared with untreated (n=40) patients were characterized by diminished severity of oxidative stress at the account of lower levels of lipid peroxidation products and augmented compensatory potential of the endogenous antioxidant system.


Subject(s)
Myocardial Infarction/drug therapy , Oxidative Stress/drug effects , Picolines/therapeutic use , Administration, Oral , Catalase/blood , Female , Glutathione Peroxidase/blood , Humans , Injections, Intramuscular , Injections, Intravenous , Lipid Peroxidation , Male , Middle Aged , Models, Theoretical , Myocardial Infarction/blood , Myocardial Infarction/enzymology , Picolines/administration & dosage , Superoxide Dismutase/blood , Time Factors
14.
Ter Arkh ; 74(9): 60-3, 2002.
Article in Russian | MEDLINE | ID: mdl-12418123

ABSTRACT

AIM: To study clinical and laboratory manifestations of hormonal activity in hypertensive patients with undifferentiated adrenal tumors. MATERIAL AND METHODS: 40 patients (19 males and 21 females aged 16-60 years) with undifferentiated adrenal tumors were examined. They were treated surgically. The results of the examination were compared with histological evidence on the resected adrenals. Clinical and laboratory signs of hormonal activity of the tumor were ascertained. RESULTS: Clinical symptoms in patients with adrenal tumors differed from those of typical symptoms of Icenko-Cushing, Cohn syndromes, pheochromocytoma. Hypertension in patients with cortical tumor may arise because of high synthesis of hydrocortisone, in patients with medullary tumor--of catecholamines. However, the level of hormones was not high enough for development of classic syndromes. That's why these tumors were named undifferentiated. CONCLUSION: Adrenal cortical tumors have signs of mixed androgeno-mineral-glucocorticoid activity. In medullary adrenal tumors hypersecretion of catecholamines is associated with cortical hyperfunction.


Subject(s)
Adrenal Gland Neoplasms/complications , Hypertension/complications , Adolescent , Adrenal Gland Neoplasms/pathology , Adult , Cell Differentiation , Female , Humans , Male , Middle Aged
15.
Med Tr Prom Ekol ; (6): 23-7, 2001.
Article in Russian | MEDLINE | ID: mdl-11521295

ABSTRACT

The authors suggest a method evaluating acoustic situation on traffic pathways with restricted volume of direct measurements. The regression equations obtained could forecast equivalent noise levels changing with city growth and with shifts of traffic flow between routes.


Subject(s)
Noise, Transportation/adverse effects , Humans , Medical Illustration , Urban Health
16.
Planta ; 212(5-6): 880-7, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11346965

ABSTRACT

Potato (Solanum tuberosum L. cv. Desiré) plants with reduced amounts of P-protein, one of the subunits of glycine decarboxylase (GDC), have been generated by introduction of an antisense transgene. Two transgenic lines, containing about 60-70% less P-protein in the leaves compared to wild-type potato, were analysed in more detail. The reduction in P-protein amount led to a decrease in the ability of leaf mitochondria to decarboxylate glycine. Photosynthetic and growth rates were reduced but the plants were viable under ambient air and produced tubers. Glycine concentrations within the leaves were elevated up to about 100-fold during illumination. Effects on other amino acids and on sucrose and hexoses were minor. Nearly all of the glycine accumulated during the day was metabolised during the following night. The data suggest that the GDC operates far below substrate saturation under normal conditions thus allowing a flexible and fast response to changes in the environment.


Subject(s)
Amino Acid Oxidoreductases/metabolism , Antisense Elements (Genetics) , Glycine/metabolism , Mitochondria/enzymology , Solanum tuberosum/metabolism , Amino Acid Oxidoreductases/isolation & purification , Amino Acids/analysis , Carbon Dioxide/metabolism , Chlorophyll/analysis , Chromosome Mapping , Glycine Dehydrogenase (Decarboxylating) , Light , Oxygen Consumption/physiology , Phenotype , Photosynthesis/physiology , Plant Leaves/genetics , Plant Leaves/metabolism , Plants, Genetically Modified , Serine/metabolism , Solanum tuberosum/genetics
17.
Photosynth Res ; 67(3): 177-84, 2001.
Article in English | MEDLINE | ID: mdl-16228305

ABSTRACT

Carbon isotope effects were investigated for the reaction catalyzed by the glycine decarboxylase complex (GDC; EC 2.1.2.10). Mitochondria isolated from leaves of pea (Pisum sativum L.) and spinach (Spinacia oleracea L.) were incubated with glycine, and the CO(2) evolved was analyzed for the carbon isotope ratio (delta(13)C). Within the range of parameters tested (temperature, pH, combination of cofactors NAD(+), ADP, pyridoxal 5-phosphate), carbon isotope shifts of CO(2) relative to the C(1)-carboxyl carbon of glycine varied from +14 per thousand to -7 per thousand. The maximum effect of cofactors was observed for NAD(+), the removal of which resulted in a strong (12)C enrichment of the CO(2) evolved. This indicates the possibility of isotope effects with both positive and negative signs in the GDC reaction. The measurement of delta(13)C in the leaves of the GDC-deficient barley (Hordeum vulgare L.) mutant (LaPr 87/30) plants indicated that photorespiratory carbon isotope fractionation, opposite in sign when compared to the carbon isotope effect during CO(2) photoassimilation, takes place in vivo. Thus the key reaction of photorespiration catalyzed by GDC, together with the key reaction of CO(2) fixation catalyzed by ribulose-1,5-bisphosphate carboxylase, both contribute to carbon isotope fractionation in photosynthesis.

18.
Biochem Biophys Res Commun ; 265(1): 106-11, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10548498

ABSTRACT

Inside-out submitochondrial particles from both potato tubers and pea leaves catalyze the transfer of hydride equivalents from NADPH to NAD(+) as monitored with a substrate-regenerating system. The NAD(+) analogue acetylpyridine adenine dinucleotide is also reduced by NADPH and incomplete inhibition by the complex I inhibitor diphenyleneiodonium (DPI) indicates that two enzymes are involved in this reaction. Gel-filtration chromatography of solubilized mitochondrial membrane complexes confirms that the DPI-sensitive TH activity is due to NADH-ubiquinone oxidoreductase (EC 1.6.5.3, complex I), whereas the DPI-insensitive activity is due to a separate enzyme eluting around 220 kDa. The DPI-insensitive TH activity is specific for the 4B proton on NADH, whereas there is no indication of a 4A-specific activity characteristic of a mammalian-type energy-linked TH. The DPI-insensitive TH may be similar to the soluble type of transhydrogenase found in, e.g., Pseudomonas. The presence of non-energy-linked TH activities directly coupling the matrix NAD(H) and NADP(H) pools will have important consequences for the regulation of NADP-linked processes in plant mitochondria.


Subject(s)
Mitochondria/enzymology , NADP Transhydrogenases/metabolism , Pisum sativum/enzymology , Solanum tuberosum/enzymology , Chromatography, Gel , Intracellular Membranes/enzymology , Isoenzymes/isolation & purification , Isoenzymes/metabolism , Kinetics , NAD/metabolism , NADP/metabolism , NADP Transhydrogenases/isolation & purification , Plant Leaves , Plant Roots , Substrate Specificity
19.
FEBS Lett ; 412(2): 265-9, 1997 Jul 28.
Article in English | MEDLINE | ID: mdl-9256232

ABSTRACT

Metabolism of glycine in isolated mitochondria and protoplasts was investigated in photosynthetic, etiolated (barley and pea leaves) and fat-storing (maize scutellum) tissues using methods of [1-(14)C]glycine incorporation and counting of 14CO2 evolved, oxymetric measurement of glycine oxidation and rapid fractionation of protoplasts incubated in photorespiratory conditions with consequent determination of ATP/ADP ratios in different cell compartments. The involvement of different paths of electron transport in mitochondria during operation of glycine decarboxylase complex (GDC) was tested in different conditions, using aminoacetonitrile (AAN), the inhibitor of glycine oxidation in mitochondria, rotenone, the inhibitor of Complex I of mitochondrial electron transport, and inhibitors of cytochrome oxidase and alternative oxidase. It was shown that glycine has a preference to other substrates oxidized in mitochondria only in photosynthetic tissue where succinate and malate even stimulated its oxidation. Rotenone had no or small effect on glycine oxidation, whereas the role of cyanide-resistant path increased in the presence of ATP. Glycine oxidation increased ATP/ADP ratio in cytosol of barley protoplasts incubated in the presence of CO2, but not in the CO2-free medium indicating that in conditions of high photorespiratory flux oxidation of NADH formed in the GDC reaction passes via the non-coupled paths. Activity of GDC in fat-storing tissue correlated with the activity of glyoxylate-cycle enzymes, glycine oxidation did not reveal preference to other substrates and the involvement of paths non-connected with proton translocation was not pronounced. It is suggested that the preference of glycine to other substrates oxidized in mitochondria is achieved in photosynthetic tissue by switching to rotenone-insensitive intramitochrondrial NADH oxidation and by increasing of alternative oxidase involvement in the presence of glycine.


Subject(s)
Cyanides/pharmacology , Glycine/metabolism , Mitochondria/drug effects , Plants/metabolism , Rotenone/pharmacology , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Oxidoreductases/metabolism , Electron Transport , Glycine Decarboxylase Complex , Glycine Dehydrogenase (Decarboxylating) , Mitochondria/metabolism , Oxidation-Reduction , Oxygen/metabolism , Plant Leaves/metabolism , Plants/enzymology
20.
FEBS Lett ; 386(2-3): 174-6, 1996 May 20.
Article in English | MEDLINE | ID: mdl-8647275

ABSTRACT

Fractionation of carbon isotopes (13C/12C) by glycine decarboxylase (GDC) was investigated in mitochondrial preparations isolated from photosynthetic tissues of different plants (Pisum, Medicago, Triticum, Hordeum, Spinacia, Brassica, Wolffia). 20 mM glycine was supplied to mitochondria, and the CO2 formed was absorbed and analyzed for isotopic content. CO2 evolved by mitochondria of Pisum was enriched up to 8% in 12C compared to the carboxylic atom of glycine. CO2 evolved by mitochondria of the other plants investigated was enriched by 5-16% in 13C. Carbon isotope effects were sensitive to reaction conditions (pH and the presence of GDC cofactors). Theoretical treatment of the reaction mechanism enabled us to conclude that the value and even the sign of the carbon isotope effect in glycine decarboxylation depend on the contribution of the enzyme-substrate binding step and of the decarboxylation step itself to the overall reaction rate. Therefore, the fractionation of carbon isotopes in GDC reaction was revealed which provides essential isotopic effects in plants in addition to the well-known effect of carbon isotope fractionation by the central photosynthetic enzyme, ribulose-1,5-biphosphate carboxylase.


Subject(s)
Amino Acid Oxidoreductases/metabolism , Carbon Isotopes , Carbon/metabolism , Chemical Fractionation , Decarboxylation , Glycine Dehydrogenase (Decarboxylating) , Mitochondria/metabolism , Plants/metabolism
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