Ethylene Formation by Isolated Chloroplast Lamellae in the Dark

1975 ◽  
Vol 30 (1-2) ◽  
pp. 58-63 ◽  
Author(s):  
Erich Elstner ◽  
Jörg Konze
Keyword(s):  
Heat Treatment ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Sulfonic Acid ◽  
Ethylene Biosynthesis ◽  
Reactive Species ◽  
Oh Radical ◽  
Ethylene Formation ◽  
Ferredoxin Reductase ◽  
Superoxide Free Radical

Abstract Ethylene Biosynthesis, Chloroplasts, Superoxide Free Radical Isolated chloroplast lamellae from spinach produce ethylene in the dark from methylmercapto-propanal (MMP) or from 2-keto-4-methyl-mercaptobutyrate (KMB) only in the presence of both NADPH and ferredoxin. Anthraquinone-2-sulfonic acid can substitute for ferredoxin. Catalase, superoxide dismutase, ethanol and ascorbate are inhibitors of NADPH-dependent ethylene forma­ tion. Isolated NADP-ferredoxin reductase in the presence of NADPH, ferredoxin and an oxygen reducing factor (ORF, isolated by heat-treatment of chloroplast lamellae) catalyzes ethylene formation from the above substrates in the dark without chloroplast lamellae. From the results it is concluded that chloroplast lamellae in the dark can reduce oxygen monovalently at the expense of NADPH, with the production of the OH-radical as the reactive species responsible for ethylene formation from MMP of KMB.

Determination of Superoxide Free Radical Ion and Hydrogen Peroxide as Products of Photosynthetic Oxygen Reduction

1975 ◽  
Vol 30 (1-2) ◽  
pp. 53-57 ◽  
Author(s):  
Erich Elstner ◽  
Claus Stoffer ◽  
Adelheid Heupel
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
The Other ◽  
Keto Acids ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen

Abstract Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H2O2 is responsible for the oxidation of hydroxylamine. Decarboxylation of α-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of α-keto acids can be used, therefor, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H2O2 and O2·-. The addition of an oxygen reducing factor (ORF, solubilized by heat - treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H2O2 , while O2·- - formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H2O2 not only by dismutation of O2·-, but also by a separate mechanism involving ORF.

Ethylene Production by Isolated Chloroplasts

1974 ◽  
Vol 29 (11-12) ◽  
pp. 710-716 ◽  
Author(s):  
E Elstner ◽  
J Konze
Keyword(s):  
Superoxide Dismutase ◽  
Oxygen Reduction ◽  
Ethylene Production ◽  
Red Light ◽  
Oh Radical ◽  
Anaerobic Conditions ◽  
Ph Optimum ◽  
Ethylene Formation ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen

Abstract Isolated chloroplast lamellae from spinach or sugar-beet leaves produce ethylene from methylmercaptopropanal (MMP) or 2-keto-4-methylmercaptobutyrate (KMB) in the light. The pH-optimum for ethylene production from M M P is 6.3; ethylene production from KMB has an apparent pH-optimum at about pH 5. Ethylene formation in red light (90 kerg ·cm -2 -sec-1) from the above substrates is stimulated by ferredoxin and inhibited by either DCMU (10-5 м), ferredoxin together with NADP, catalase, superoxide dismutase or under anaerobic conditions. From the inhibition by either DCMU, NADP or anaerobic conditions it is concluded, that an intact electron transport system from water as electron donor to oxygen as electron acceptor is necessary for ethylene form ation. H2O2 alone does not stimulate ethylene formation from M M P or KMB. Inhibition by both catalase and superoxide dismutase support the view, that ethylene formation from M M P or KMB is driven by the OH-radical, which is formed from H2O2 and the superoxide free radical ion. The presented data suggest that in addition to ferredoxin another membrane-bound factor is involved in photosynthetic oxygen reduction and ethylene formation. This factor (ORF = oxygen reducing factor) stimulates photosynthetic oxygen reduction in the presence of ferredoxin yielding H2O2, in addition to O2.- , which is the product of the autooxidation of reduced ferredoxin. During photosynthetic ethylene formation from MMP or KMB, the production of the OH-radical from H2O2 and O2.- according to H2O2+ O2 ·- → OH·+OH-+O2 (Haber and Weiss, Proc. Roy. Soc. Ser. A 147, 332 [1934], Beauchamp and Fridovich, J. Biol. Chem. 245, 4641 [1970]) seems to be the rate-limiting step.

scholarly journals Assessment of in-vitro Antioxidant/Enzymes Inhibitory Potentials of Aframomum melegueta [Roscoe] K. Schum (Grains of Paradise) Leaf, Stem Bark, Seed Bark and Seed Extracts

2020 ◽  
pp. 40-57
Author(s):  
Oludare Temitope Osuntokun ◽  
V. O. Olumekun ◽  
A. O. Ajayi ◽  
I. O. Omotuyi ◽  
A. Olonisakin
Keyword(s):  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Free Radical ◽  
Reduced Glutathione ◽  
Research Work ◽  
Radical Scavenging ◽  
Stem Bark ◽  
Oh Radical ◽  
Seed Extracts

The purpose of this research work is to evaluates the in-vitro antioxidant and antioxidant enzymes inhibition potentials of Aframomum melegueta [Roscoe] K. Schum (Grains of Paradise) Leaf, Stem Bark, Seed Bark and Seed Extracts. Aframomum melegueta is a spice with a similar composition as Ginger, that belongs to the same Zingiberaceae family, used in Nigeria, West Africa and it is used for the treatment of infectious diseases such as urinary tract infections, cancer and diabetes. Antioxidants neutralize the effect of free radicals through different ways and may prevent the body from various diseases. The plant extract were collected from a rain forest in Akugba Akoko, Ondo state, Nigeria. The plant sample was dried, pulverized, filtered with Whatman No 1 filtered paper and the filtrates was concentrated in-vacuum using vacuum rotary evaporator at 40°C and was later concentrated to dryness in a hot-air oven at 40°C. Assessment of antioxidant potentials were performed using Singleton method Total flavonoids (mg/g), Phenol (mg/g), Ferric reducing (FRAP) potentials (mg/g), Free radical scavenging ability (DPPH) (1, 1- diphenyl-2-picryhydrazyl) potentials (%),2,2’-azino-bis(3-ethylbenthiazoline-6-sulphonic acid), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging potentials (mMol/g), Fe2+ chelation potentials (%) and OH Radical Scavenging potentials (%) were evaluated. Antioxidant enzymes of plant were assessed using Bentller method, Superoxide Dismutase (SOD) (%), Reduced Glutathione (GSH) (%), Catalase (CAT) and Glutathione Peroxidise (GPX) were evaluated. Seed extract among other extracts of Aframomum melegueta has the highest quantity of flavonoids, Phenol, FRAP, DPPH, ABTS, Fe2+ chelation and OH radical scavenging potential. The leaf extract of A. meleguata has the highest percentage of Superoxide Dismutase (SOD) and Catalase (CAT) while stem bark of Aframomum melegueta has the highest percentage of Reduced Glutathione (GSH) and Glutathione Peroxidise (GPX).it can be deduced from this research work that all parts of the A. melegueta has pharmacological and therapeutic activities judging from literature that A. melegueta can be used to prevent oxidative damage by ROS (Reactive oxygen species) reacting with free radical chelating and catalytic metals  which can be used to reduce and prevent various diseases like heart disease, cancer, DNA degeneration, pulmonary and neurological disorder. SOD, GPX, GSH help to control cytokins induced peroxidise level and mediate signal transduction in mammalian cells. It can be deduced that Aframomum melegueta should be the focal point in human diet, natural herbal drug supplement and even in addition to conventional drug to improve the potency and quality of natural drug system. The use of Aframomum melegueta should be encouraged. These results show the potential of Aframomum melegueta as a source of bioactive compounds to be used for pharmaceutical, nutraceutical, and cosmeceutical applications.

Reaotive oxygen generation by azomethine H: a new antimalarial drug

1995 ◽  
Vol 73 (8) ◽  
pp. 1189-1194 ◽  
Author(s):  
Ethel L. B. Novelli ◽  
Assunta M. M. Silva ◽  
Jose L.V.B. Novell F. ◽  
Paulo R. Curi
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Superoxide Radical ◽  
Alanine Transaminase ◽  
Superoxide Dismutase Activity ◽  
Acid Solutions ◽  
Oxygen Generation ◽  
Hydrochloric Acid Solutions ◽  
Superoxide Free Radical ◽  
Important Intermediate

Superoxide radical [Formula: see text] is a free radical that may be involved in various toxic processes. Cu—Zn superoxide dismutase catalyzes the dismutation of the superoxide free radical and protects cells from oxidative damage. A rat bioassay validated for the identification of the toxic effects of azomethine H revealed increased serum activities of amylase, alanine transaminase, and alkaline phosphatase. The lipoperoxide and bilirubin concentrations were also increased in animals that received azomethine H (1 g/kg) from ascorbic or hydrochloric acid solutions. Azomethine H increased Cu–Zn superoxide dismutase activity. This elevation of Cu–Zn superoxide dismutase activity was highest on the 7th day and was at levels comparable with those of control rats from day 60 onwards. Superoxide is an important intermediate in the action and toxicity of azomethine H.Key words: azomethine H, superoxide radical, antimalarial, toxicity.

Production of OH-Radical-Type Oxidant by Lucigenin

1998 ◽  
Vol 53 (1-2) ◽  
pp. 9-14 ◽  
Author(s):  
Ingrid Heiser ◽  
Angelika Muhr ◽  
Erich F. Elstner
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
Ethylene Production ◽  
Oh Radical ◽  
Redox Active ◽  
Nad Oxidoreductase ◽  
Clostridium Kluyveri ◽  
Radical Type

AbstractIn the presence of NADH- reductases (dihydrolipoamide: NAD oxidoreductase E. C.l.8.1.4 from pig heart or from Clostridium kluyveri; frequently also addressed as “diaphorases”) and NADH lucigenin strongly increases ethylene production from a-ketomethylthiobutyrate (KMB) as an indicator for strong oxidants of the OH-radical type. These reactions are further stimulated in the presence of Fe3+ ions. With these NADH- “diaphorases”, the structurally similar poison, paraquat, in the absence or presence of Fe3+ has no effect. With ferredoxin-NADP reductase (E. C.1.18.1.2.), however, paraquat reacts quasi identical to lucigenin. Superoxide dismutase, catalase, free radical- or OH - scavengers such as mannitol, propylgallate, DABCO, and desferal inhibit the reaction whereas EDTA (in the presence or absence of added Fe3+) is stimulatory. From these data we conclude that the superoxide - indicator LUC is redox-active after unspecific coupling to several almost ubiquitory NAD(P)H- reductases catalyzing monovalent oxygen reduction. Lucigenin thus should no longer be used as a “specific” superoxide indicator. This report is in agreement with very recent results by Liochev and Fridovich (Arch. Biochem. Biophys. 337, 115 [1997]) and Vasquez-Vivar et al. (FEBS Lett. 403, 127 (1997).

Intratracheal injection of nickel chloride and copper–zinc superoxide dismutase activity in lung of rats

1992 ◽  
Vol 70 (5) ◽  
pp. 709-711 ◽  
Author(s):  
Ethel L. B. Novelli ◽  
Ney L. Rodrigues ◽  
Bartolomé O. Ribas ◽  
Paulo R. Curi
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Nickel Content ◽  
Experimental Period ◽  
Nickel Chloride ◽  
Superoxide Dismutase Activity ◽  
Copper Zinc Superoxide Dismutase ◽  
Superoxide Free Radical ◽  
Copper Zinc ◽  
Intratracheal Injection

Superoxide radical [Formula: see text] is a free radical that may be involved in various toxic processes. Cu–Zn superoxide dismutase catalyses the dismutation of the superoxide free radical and protects cells from oxidative damage, and it has been used clinically. The concentration of Ni2+ and Cu–Zn superoxide dismutase activity were measured in lungs of rats at time intervals of 5, 12, 19, 26, 33, and 40 days following an intratracheal injection of 127 nmol of NiCl2. Nickel chloride increased nickel content and resulted in a significant increase of Cu–Zn superoxide dismutase activity in lungs. This elevation of Cu–Zn superoxide dismutase activity was highest on the 12th day (approximately threefold) and is at levels comparable to controls rats on day 40 onwards. Since Cu–Zn superoxide dismutase activity was increased in lung throughout our experimental period without corresponding increases of Cu2+ and Zn2+, we speculate that the elevation of Cu–Zn superoxide dismutase activity might be due to an increased half-life of the enzyme, induced by nickel.Key words: nickel chloride, intratracheal, Cu–Zn superoxide dismutase, lung.

Involvement of the Superoxide Free Radical Ion in Photosynthetic Oxygen Reduction

1974 ◽  
Vol 29 (9-10) ◽  
pp. 559-563 ◽  
Author(s):  
Erich F. Elstner ◽  
Adelheid Heupel
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
Radical Ions ◽  
Reaction Sequence ◽  
Initiation And Propagation ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen ◽  
A Chain ◽  
Stimulation Of

Abstract Photosynthetic oxygen reduction by isolated chloroplast lamellar systems has been studied with the aid of superoxide dismutase. Two mechanisms of oxygen reduction by illuminated chloroplast lamellar systems can be differentiated: 1. In the presence of low potential electron acceptors like AQ or MV the superoxide free radical ion is the product of autooxidation of the reduced acceptor. Addition of superoxide dismutase has no influence on the initial rates of oxygen reduction. 2. Stimulation of photosynthetic oxygen reduction by o-diphenols is only observed in the absence of superoxide dismutase and ascorbate; apparently the superoxide free radical ions is involved in both initiation and propagation of a chain reaction. If the ferredoxin-stimulated photosynthetic oxygen reduction is measured, both ascorbate and superoxide dismutase are active as inhibitors. By heating suspensions of chloroplast lamellar systems, a substance is released into the supernatant which exhibits the activity of an oxygen reducing factor (ORF) with properties similar to o-diphenols: The stimulation of photosynthetic oxygen reduction is reversed by addition of either SDM or ascorbate. A reaction sequence for photosynthetic oxygen reduction in the presence of ferredoxin is considered, which is initiated by the superoxide free radical ion produced by autooxidation of reduced ferredoxin; the superoxide free radical ion "activates" an endogenous oxygen reducing factor, which in this "active" state can reduce oxygen to O2·-. The presence of either superoxide dismutase or ascorbate yields in chain termination by scavenging the superoxide free radical ion

Effect of 1,3,6-trimethyl-5-hydroxyuracil succinate on the antioxidant system and free-radical processes in the liver of adult and old rats treated with carbon tetrachloride

2018 ◽  
pp. 55-59
Author(s):  
И.Д. Габдрахманова ◽  
В.А. Мышкин ◽  
Д.А. Еникеев ◽  
А.Р. Гимадиева
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Carbon Tetrachloride ◽  
Antioxidant System ◽  
Complex Compound ◽  
Antiradical Activity ◽  
Conjugated Dienes ◽  
Experimental Animals ◽  
Old Rats ◽  
Radical Processes

Цель исследования: изучение влияния сукцината 1,3,6-триметил-5-гидроксиурацила на антиоксидантную систему и свободнорадикальные процессы в печени взрослых и старых крыс при воздействии тетрахлорметана. Методика. В эксперименте использованы половозрелые животные 12-месячного возраста со средней массой 250 г и старые животные 24-месячного возраста, средней массой 395 г по 30 особей в каждой возрастной группе. Токсическое поражение печени вызывали подкожным введением 50%-ного масляного раствора тетрахлорметана (ТХМ, 2 г/кг) в течение 4 сут. Одновременно с токсикантом опытным животным внутрибрюшинно вводили водный раствор коплексного соединения сукцинат-1,3,6-триметил-5-гидроксиурацила (2,5 мг/100 г) 3 раза в сут. в течение первых 4 сут. и в течение последующих 3 сут. 1 раз в сут. Контролем служили опытные животные, которым вводили физиологический раствор в том же объеме. Изучали окислительную модификацию белков, перекисное окисление липидов (по содержанию ТБК-реагирующих продуктов, уровню гидроперекисей липидов и содержанию диеновых конъюгатов). Состояние антиоксидантной системы оценивали по активности ферментов супероксиддисмутазы, каталазы и глутатионпероксидазы, определяемых биохимическими методами. Антирадикальную активность комплексного соединения и его составляющих субстанций исследовали в модельной системе «этилбензол-ледяная уксусная кислота» с вычислением константы К - скорости взаимодействия перекисных радикалов с молекулами изучаемого соединения в сравнении с эталонным антиоксидантом-ионолом с витамином Е. Результаты. Сукцинат + 1,3,6-триметил-5-гидрокси-урацила существенно снижает токсическое действие ТХМ на печень взрослых и старых крыс, устраняет дисбаланс в системах свободнорадикального окисления белков у старых крыс, статистически значимо улучшает показатели свободнорадикального окисления (СРО) липидов в печени взрослых и старых крыс: снижает уровень продуктов ПОЛ - гидроперекисей, диеновых конъюгатов, ТБК-реагирующих продуктов, а также улучшает работу антиоксидантной системы (АОС), повышая активность каталазы, супероксиддисмутазы и глутатионпероксидазы. Установлена высокая антирадикальная активность изучаемого препарата сопоставимая с активностью эталонного антиоксиданта ионола. Заключение. Сукцинат и его производные способны выступать как индивидуальные вещества с непосредственным антирадикальным механизмом действия, а не только как стимуляторы ферментативных систем антиоксидантной защиты. Aim. To study the effect of a complex compound, 1,3,6-trimethyl-5-hydroxyuracil succinate, on the antioxidant system and free radical processes induced by carbon tetrachloride in the liver of adult and old rats. Methods. The study used sexually mature animals aged 12 months and weighing 250 g and old animals aged 24 months weighing 395 g (total n= 60, 30 rats in each age group). Toxic damage of liver was induced by subcutaneous injections of a 50% oil solution of carbon tetrachloride (CTC) at 2 g/kg for 4 days. Together with the toxicant, experimental animals were injected with a water solution of a complex compound, succinate 1,3,6-trimethyl-5-hydroxyuracil, at a dose of 2.5 mg/100 g, i.p., 3 times per day for the first 4 days and once daily for the following 3 days. Experimental animals were used as controls, which were administered saline in the same volume. Oxidative modifications of proteins, lipid peroxidation (by levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and conjugated dienes) were studied. Condition of the antioxidant system was evaluated by activities of superoxide dismutase, catalase, and glutathione peroxidase using biochemical methods. Antiradical activity of the complex compound and its components was studied in a model system of ethylbenzene-glacial acetic acid; the K7 constant of the rate of peroxide radical interaction with molecules of the studied compound was compared with the reference antioxidant ionol with vitamin E. Results. Succinate +1.3.6-trimethyl-5-hydroxyuracil, considerably reduced TXM hepatotoxicity in adult and old rats; removed the disbalance in free radical systems of protein oxidation in old rats; significantly improved indexes of free-radical oxidation (FRO) of hepatic lipids in adult and old rats; decreased levels of LP products, hydroperoxides, conjugated dienes, and TBARS, and enhanced performance of the antioxidant system (AOS) by increasing activities of catalase, superoxide dismutase, and glutathione peroxidase. The study demonstrated a high antiradical activity of the study drug comparable with the activity of the reference antioxidant, ionol. Сonclusion. Succinate and its derivatives can perform as individual substances with a direct antiradical mechanism of action rather than as stimulators of enzymic systems of antioxidant defence.

State of the enzyme link of antioxidant protection in boys with hypoandrogenism

2020 ◽  
Vol 40 (4) ◽  
pp. 32-36
Author(s):  
L. K. Parkhomenko ◽  
◽  
L. A. Strashok ◽  
S. I. Turchina ◽  
G. V. Kosovtsova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Glutathione Peroxidase ◽  
Free Radical Oxidation ◽  
Conjugated Dienes ◽  
Delayed Puberty ◽  
Control Group ◽  
Antioxidant Protection ◽  
Radical Oxidation

Recently, interest in the problem of free radical oxidation in biological membranes, which is directly related to both the normal functioning of cells and the occurrence, course and outcome of many pathological conditions, has increased again in clinical medicine. The aim was to determine the role and impact of antioxidant defense in boys with hypoandrogenism. The study involved 75 adolescents with hypoandrogenism aged 13–18 years, who underwent a complex of clinical and laboratory examinations. All patients were conducted complex of anthropometric research and determination of the degree of delayed puberty, laboratory and instrumental examination. Free radical oxidation was determined by the levels of malondialdehyde, conjugated dienes, carbonated proteins, superoxide dismutase and catalase in the serum, and restored glutathione and glutathione peroxidase in whole blood. Based on their determination, the coefficient of oxidative stress was calculated. Statistical processing of results was performed using parametric and nonparametric methods. The study of indicators of the free radical oxidation process found that adolescents with hypoandrogenism have multidirectional changes in the oxidation of proteins and lipids, namely: the level of conjugated dienes increases, the concentration of malondialdehyde remains at the level of the control group, and the level of carbonated proteins tends to decrease. As for the activity of antioxidant protection enzymes, a significant decrease in the level of glutathione peroxidase was detected, while the level of superoxide dismutase and catalase remained at the level of normative indicators. Oxidative stress accompanies and is one of the pathogenetic links in the formation or maintenance of the state of hypoandrogenism in boys. This requires the use of antioxidants, the complex of which must be selected individually.

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