Age-related changes in superoxide dismutase, glutathione peroxidase, catalase and xanthine oxidoreductase/xanthine oxidase activities in the rabbit cornea

The activities of superoxide dismutase, glutathione peroxidase (GPX) and catalase--the enzymatic scavengers of reactive oxygen species and the activities of xanthine oxidoreductase and xanthine oxidase, an enzyme known to generate reactive oxygen species, were studied in the corneas of normal rabbit eyes of various ages (1 month--young eyes; 4-9.5 months--young adult eyes; 2.0-2.75 years--middle aged eyes; 3.0-5.0 years--aged eyes). The activities of GPX, superoxide dismutase, xanthine oxidoreductase and xanthine oxidase were investigated biochemically in the scraped corneal epithelium. Catalase activity was detected histochemically in the corneal epithelium and endothelium. The results show that young corneas revealed lower activities of all the antioxidant enzymes investigated than did young adult corneas, in which enzymatic activities reached their maximum. In middle-aged corneas, GPX and catalase activities remained approximately at the same levels as seen in young adult corneas, whereas superoxide dismutase activity was decreased. In aged corneas, the activities of all antioxidant enzymes were dramatically decreased or even lost (catalase activity in the corneal endothelium). In contrast, xanthine oxidoreductase activity only slightly decreased with age and the xanthine oxidase proportion of total xanthine oxidoreductase remained unchanged. GPX, superoxide dismutase and catalase are important antioxidant enzymes protecting the cornea against the oxidative damage. Because the activities of these enzymes are lower in young animals and greatly reduced in aged animals, it is suggested that young and particularly aged corneas might be more susceptible to oxidative stress than are young adult corneas. This presumption is supported by the fact that the activities of prooxidant enzymes (xanthine oxidoreductase/xanthine oxidase) are only slightly decreased in aged corneas as compared to young adult corneas so that some imbalance between antioxidant and prooxidant enzymes exists already in the normal aged corneas.     

Age-related activity changes in actomyosin ATPase and arginine phosphokinase in male Drosophila melanogaster Meig

The specific activity of each of the two enzymes primarily concerned with the energy metabolism of flight muscle contraction was determined in male Drosophila melanogaster, from emergence through 5 weeks postemergence. Ca++-activated actomyosin ATPase activity rose rapidly from a minimum at emergence to a peak level at 4-5 days, falling gradually thereafter to a minimum level at 10-11 days postemergence, with no change thereafter. Arginine phosphokinase activity rose more gradually to a maximum at 11-12 days postemergence and then fell slowly to a minimum at 18-19 days. These data represent a sequential pattern of biochemical changes similar to those previously observed in other dipteran species, confirming the primary role of a genetic program for maturation and senescence of flight ability in holometabolous adult insects at the functional and underlying cellular, biochemical levels.     

Age-related activity of catalase in different genotypes of drosophila melanogaster

The enzyme catalase protects aerobic organisms from oxygen free radical damage by converting hydrogen peroxide to molecular oxygen and water before it can decompose to form the highly reactive hydroxyl radical. This damage has been implicated in the increased risk of disease and death associated with aging. In order to study the age-specific activity of catalase in male D. melanogaster three different genotypes (Oregon w.t., ebony mutant, and the F₁ hybrids of the two), whose mean life spans are about 55, 40, and 63 days, respectively, were used in the experiments. As the mean life span of the mutant is the shortest the enzyme activity was measured until the 43rd day, whereas in Oregon w.t., it continued until the 72nd day and in hybrids until the 79th day (longest-lived group). Although the enzyme activity in mutant flies increased sharply till the 9th day (and attained the highest level), later it declined sharply. In the other genotypes, the enzyme activity increased gradually until the 20–25th days, and then declined steadily in comparison to that of the ebony mutant. We found that higher catalase activity is associated with reduced life span for ebony mutant. It is obvious that some relationship exists between life span and antioxidant enzymes; however, a review of the literature does not at the moment allow as to understand the underlying mechanism involved in aging.     

Glutathione peroxidase, glutathione reductase and glutathione transferase activities in the human artery, vein and heart

The continuous exposure to blood components, including prooxidants, makes the blood vessel wall susceptible to oxidative stress and free radical mediated reactions (Henning and Chow, 1988; Stamm et al., 1989; Halliwell and Gutteridge, 1984). Free radicals can be produced extracellularly via the respiratory bursts of activated neutrophils, or intracellularly, via oxidation of hypoxanthine by xanthine oxidase (Henning and Chow, 1988; Stamm et al., 1989; Rubanyi, 1988). Microsomal enzymes such as lipoxygenase and cyclooxygenase may also be a source of reactive species of oxygen (Henning and Chow, 1988; Stamm et al., 1989; Rubanyi, 1988; Mason et al., 1980). It has been proposed that free radicals are involved in the initiation and progression of various cardiovascular diseases including arteriosclerosis (Henning and Chow, 1988; Stamm et al., 1989; Yagi, 1988; Jürgens et al., 1987). Thus the adequacy of the defence systems against free radicals is critical for the susceptibility of blood vessel wall to oxidative damage. Among the enzymatic systems capable of protecting the cell against oxidative injury, selenium dependent glutathione peroxidase (Se-GSH-px), glutatione reductase (GSSG-rx) and glutathione transferase (GST) play a crucial role (Flohe' et al., 1976; Mannervik and Danielson, 1988). Using glutathione (GSH) as a cofactor, Se-GSH-px reduces H2O2 to water and organic hydroperoxides to the corresponding alcohols (Flohe' et al., 1976). This reaction leads to conversion of GSH into its oxidized form (GSSG). In the presence of NADPH, GSSG-rx is able to reduce the oxidized glutathione.(ABSTRACT TRUNCATED AT 250 WORDS)     

The interrelation of glutathione reductase,catalase, glutathione peroxidase,superoxide dismutase,and glucose-6-phosphate in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is the most common form of inflammatory arthritis, a systemic autoimmune disease characterized by chronic inflammation of the synovial joints, ultimately leading to joint destruction and permanent disability, affecting 1% of the world population. Oxidative stress in rheumatoid inflammation, due to the fact that antioxidant systems are impaired in RA and caused by fee radicals, might have an essential role in etiology of RA. This review includes the interrelation of antioxidants against free radicals in RA patients. There is much evidence that antioxidant team that covers glutathione reductase, catalase, glutathione peroxidase, superoxide dismutase, and glucose-6-phopshate destroy reactive oxygen species and other free radicals through enzymatic as well as nonenzymatic means. The change in relative levels of antioxidants vis-à-vis free radical formation and level could be used as indicators for effective and earlier diagnosis of RA.     

Control of growth and positional information by the graded vestigial expression pattern in the wing of Drosophila melanogaster

The size and shape of organs depend on cellular processes such as cell proliferation, cell survival, and spatial arrangement of cells. In turn, all of these processes are a consequence of positional identity of individual cells in whole organs. Links of positional information with organ growth and pattern expression of genes is a little-addressed question. We show that differences in vestigial expression between neighboring cells of the wing blade autonomously and nonautonomously affect cell proliferation along the proximo-distal axis. On the other hand, uniform expression of vestigial inhibits cell proliferation and also perturbs the shape of wing blade altering the preferential orientation of cell divisions. Our observations provide evidence that local cell interactions, triggered by differences in vestigial expression between neighboring cells, confer positional values operating in the control of growth and shape of the wing.     

Age-related changes in catalase and peroxidase activities in the excised leaves of Eleusine coracana Gaertin. cv PR 202 during senescence

Changes in the activities of the enzymes catalase and peroxidase were studied in the excised leaves of ragi (Eleusine coracana Gaertn. cv PR 202) plants belonging to different ages. Catalase exhibited a positive and peroxidase a negative correlation with the changes in chlorophyll. Catalase and peroxidase were negatively correlated with each other. Peroxidase exhibited an age-related drift in its activity. Kinetin could maintain the levels of chlorophyll and catalase, and also caused an increase in peroxidase activity. Both indoleacetic acid and gibberellic acid had no effect on the changes of chlorophyll but increased peroxidase activity. Catalase levels were maintained by indoleacetic acid but gibberellic acid had no effect on this enzyme.     

Physiological,anatomical, and behavioral changes after acoustic trauma in Drosophila melanogaster

Noise-induced hearing loss (NIHL) is a growing health issue, with costly treatment and lost quality of life. Here we establish Drosophila melanogaster as an inexpensive, flexible, and powerful genetic model system for NIHL. We exposed flies to acoustic trauma and quantified physiological and anatomical effects. Trauma significantly reduced sound-evoked potential (SEP) amplitudes and increased SEP latencies in control genotypes. SEP amplitude but not latency effects recovered after 7 d. Although trauma produced no gross morphological changes in the auditory organ (Johnston’s organ), mitochondrial cross-sectional area was reduced 7 d after exposure. In nervana 3 heterozygous flies, which slightly compromise ion homeostasis, trauma had exaggerated effects on SEP amplitude and mitochondrial morphology, suggesting a key role for ion homeostasis in resistance to acoustic trauma. Thus, Drosophila exhibit acoustic trauma effects resembling those found in vertebrates, including inducing metabolic stress in sensory cells. This report of noise trauma in Drosophila is a foundation for studying molecular and genetic sequelae of NIHL.Noise-induced hearing loss (NIHL) is a pervasive and growing health issue arising from occupational and recreational hazards, with significant costs in health care and personal quality of life. Despite this, the molecular and physiological mechanisms involved in the etiology or recovery from injury are not yet fully understood. Importantly, intense acoustic trauma can induce permanent damage—unlike other vertebrates, mammals cannot regenerate auditory hair cells (1, 2). NIHL associated with permanent changes in auditory sensitivity causes multiple consistent effects: stereocilia bundle disruption, inner (IHC) and outer hair cell (OHC) death or damage, supporting cell tissue disruption, and eventual spiral ganglion cell damage or loss (3–7). Most studies to date used mammalian model organisms such as mice (8, 9), rats (10), and guinea pigs (11–14). These animals have difficult access to the inner ear inside the temporal bone and high maintenance costs coupled with relatively long generation times.Drosophila is a compelling alternative model system with strong genetic tools, inexpensive production of large numbers of animals, and an accessible auditory system that is becoming better understood genetically and physiologically. During courtship, Drosophila males vibrate their wings to produce a courtship song composed of pulse and sinusoidal components (15, 16). This song facilitates species identification and mate selection (16, 17). Drosophila males and females detect airborne vibrations via Johnston’s organ (JO) in the second antennal segment (18). The JO is an array of chordotonal mechanoreceptors (or scolopidia; Fig. 1 A–C). Via the aristae, acoustic energy is transformed to rotational movement of the third antennal segment, activating mechanosensitive channels on JO neuron dendrites. Like vertebrate hair cells, JO neurons are ciliated and respond to mechanical stimulation. Although JO has morphologically diverged from hair cells in the human inner ear, the genetic program for its development shares a strong homology (19, 20). For example, the Atoh1 gene required for vertebrate auditory hair cell specification was found by direct homology to the fly atonal gene required for JO specification and atonal/Atoh1 genes can be functionally exchanged between mice and flies (21, 22). The advantages of studying hearing in Drosophila are that the genome is fully sequenced, genetic tools for extensively manipulating the genome are at hand, genetic background effects can be effectively eliminated, and large numbers of individuals can be tested.Open in a separate windowFig. 1.Organization of Drosophila JO and physiological response to sound. (A) Deconvolution micrograph of labeled scolopidia in JO. The actin scolopale rods are labeled with phalloidin (magenta), mitochondria in some JO neurons are labeled with mito-GFP (green), and nuclei are labeled with TOPRO-3 (blue). (B) Schematic diagram of an individual scolopidium, oriented and colored similarly to scolopidia in A. (C) Approximate longitudinal section of JO in an untraumatized control 40AG13 fly. bb, basal bodies; cap, dendritic cap; cd, ciliary dilation; m, membranous structure; mt, mitochondria; N, nuclei of JO neurons; ScN, nuclei of scolopale cells; t, trachiole. (Scale bar: 1 μm.) (D) Example of SEPs recorded in response to acoustic stimulation (stim). The top trace is the synthetic courtship song pulse stimulus; immediately below is the resulting SEP, with the analyzed amplitude and latency parameters indicated. The bottom trace shows multiple SEPs from a wild-type fly in response to a pulse train.In this study, we establish Drosophila as an inexpensive and flexible model system for genetic and physiological study of NIHL. We exposed two control strains [Canton-S (CS) and 40AG13] to acute acoustic trauma and examined physiological, behavioral, and anatomical effects. Our findings show immediate effects on auditory function, with reduced and delayed evoked activity. Although evoked potential amplitudes were restored after 7 d, the latency of these potentials did not fully recover and we found significant changes in JO neural mitochondrial morphology. We also tested mutant flies with a reduced copy number of nervana 3 (nrv3) encoding a Na⁺/K⁺ ATPase β subunit expressed in JO neurons (23). We hypothesized that compromised JO ionic homeostasis would confer susceptibility to noise trauma. Indeed, nrv3 heterozygotes showed increased sensitivity to trauma and a significantly reduced auditory functional recovery.     

Age-associated changes in viability genetic loads of Drosophila melanogaster

The effect of age upon genetic loads for egg-to-adult viability was analysed by comparisons of homozygous and heterozygous progeny of Drosophila melanogaster. Among 74 second chromosome groups of homozygotes, viability was significantly lowered when the chromosomes originated from 30–35 days old parents ($\text{x}\text{?}\text{=22·6 ± 1·2}\text{per cent}$) in comparison with the same chromosomes when they originated from the same parents at 1–5 days of age ($\text{x}\text{?}\text{=29·3 ± 1·4}\text{per cent}$). Among the heterozygous controls (N=37 chromosomal combinations) the viability was practically equal (30·5 ± 1·0 per cent and 30·2 ± 1·3 per cent) for the progeny of same parents when, respectively, 1–5 and 25–30 days of age. The viability of the second chromosomal homozygotes (N=48) whose parents were of quite different age (i.e. young mother $\text{x}\text{?}$ old father and vice versa) was insignificantly smaller than the viability of the heterozygous controls (28·7 ± 1·8 and 28·5 ± 1·8), showing an absence of maternal effect.     

Aging changes of riboflavin concentration and glutathione reductase activity in erythrocytes

Aged erythrocytes obtained by fractionation using gradient centrifugation with Dextran 40, showed lower glutathione reductase activity and riboflavin content than young cells. However, both young and old cells displayed almost the same increase in enzyme activity upon addition of flavin adenine dinucleotide to the test hemolysate in vitro. The lipid peroxide content in the cell membranes showed no consistent changes with aging.     

Age-related changes in rat liver total protein and transferrin synthesis

An in vitro cell-free system from rat liver was designed to study the effect of age on the synthesis of total liver protein and on the synthesis of transferrln in the liver. Transferrin synthesis was determined by immunoassay. Total protein synthesis was greatest at 6 months of age and then decreased to 24 months of age. There was a significant increase in protein synthesis between 24 and 30 months of age. Transferrln synthesis followed this same general pattern except that no senescent increase in synthesis was observed.     

Age-related changes in glutathione availability and skeletal muscle carbonyl content in healthy rats

The free radical theory of aging proposes that oxidative stress plays a key role in the aging process. By altering muscle protein degradation rates, it could accelerate the age-related loss of muscle proteins. Glutathione (GSH), one of the main body antioxidants, could prevent this phenomenon, but its concentration decreases during aging. Our aims were to have a better understanding of the mechanisms of the age-related decrease in glutathione availability and of the links with sarcopenia. Male Wistar rats aged 6, 9, 12, 15, 19, 22, 25 and 28 months (n = 6 per age) were used to measure plasma and skeletal muscle protein carbonyl content, plasma total and free cyst(e)ine content, liver and muscle glutathione content as well as liver GSSG reductase, GSH peroxidase, GSH transferase and gamma glutamyl cysteine synthetase (GCS) activities. Although tissue glutathione content decreased with age, the other markers of oxidative stress were little changed during aging. In particular, muscle protein carbonyl content was unchanged. Variations in glutathione availability were not explained by cyst(e)ine availability but depended on gamma GCS activity. The stability of skeletal muscle carbonyl content during aging suggests a very efficient degradation of oxidized proteins in muscle.     

Age-related changes in total protein and collagen metabolism in rat liver

Liver collagen levels are determined by a balance between synthesis and degradation, processes known to have rapid rates in growing animals. We report age-related changes in liver collagen synthesis and degradation rates, as well as protein synthesis rates, in rats at five ages from 1 to 24 mo. Fractional collagen synthesis rates were determined after injection of [14C]proline with a flooding dose of unlabeled proline and its incorporation as hydroxy-[14C]proline into proteins. Fractional protein synthesis rates were based on the uptake of [14C]proline into proteins. Fractional collagen degradation rates were calculated from the difference between collagen fractional synthesis and deposition rates. Fractional rates of collagen synthesis were similar between 1 mo (23.0% +/- 4.6%/day) and 24 mo (19.6% +/- 3.4%/day) of age. Collagen deposition into the extracellular matrix was extremely low at every age studied; therefore degradation pathways accounted for the bulk of the collagen synthesized. The mean fractional synthesis rate for the total protein pool was unaltered between 1 mo (105.0% +/- 7.2%/day) and 15 mo (89.9% +/- 6.0%/day) of age, after which it increased to 234.9% +/- 33.0%/day (p less than 0.05) by 24 mo of age. These results indicate that liver collagen and total protein synthesis rates were maintained at relatively high levels during development and maturity but that protein synthesis rates were highest in senescent animals.     

Antioxidative effects of melatonin in Drosophila melanogaster: Antagonization of damage induced by the inhibition of catalase

In Drosophila melanogaster strain Canton S, the catalase inhibitor 3-amino-1,2,4-triazole was used to enhance oxidative stress from endogenous sources. This treatment was chosen as an alternative to direct administration of oxidants, which would cause damage and interact with melatonin already in the extracellular space before they reach the intracellular compartments. Male flies were kept in constant darkness and fed 1% sucrose as the only diet, with or without additions of melatonin (2 mM), inhibitor (100 mM), or combinations of both. After 20 or 24 hr, most of the animals exposed to 3-amino-1,2,4-triazole only had died, whereas a large number of flies had survived the inhibitor treatment in the presence of melatonin. Protein carbonyl, an indicator of oxidative protein modification, and lipid peroxidation, as determined by the formation of malondialdehyde and 4-hydroxyalkenal, were measured in flies treated for 20 hr. Melatonin alone did not substantially change these parameters, but prevented the increase in protein carbonyl caused by the catalase inhibitor. The effect of 3-amino-1,2,4-triazole on lipid peroxidation was relatively minor, but a clear-cut inhibition was found after simultaneous administration of melatonin. The preferential suppression of oxidative damage of proteins, as compared to lipids, indicates a particular protective role for melatonin in the aqueous phase of cellular compartments.     

Superoxide dismutase, catalase and glutathione peroxidase activities in the liver of young and old mice: linear regression and correlation

Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GP) were determined in the liver of 15 young (3-5 months) and 15 old (23-26 months) female CBA mice. Although, the activities of all three enzymes decreased in aging, only the SOD decline was statistically significant (P<0.01). The pair wise correlation analysis exhibited an almost identical positive correlation between SOD and CAT in the liver of both young and old mice (r=0.57), whereas the correlative links between the enzymatic pairs of SOD-GP and CAT-GP were increased in aging. Close to zero in the young group (r=-0.08), the coefficient of correlation between SOD and GP became highly significant in the group of old mice (r=0.66; P<0.01). When the coefficients of pair wise and partial correlation were compared, practically no differences were found for the young mice, whereas all three partial coefficients were decreased in the group of old animals. Estimation of the linear regression between the enzymatic pairs revealed higher coefficients of regression and lower intercepts in the group of old mice. The results imply stronger correlative links between the antioxidant enzymes in the liver of old mice, compared with the same indices in the liver of young animals.     

Heat tolerance changes with age in normal and irradiated Drosophila melanogaster

The survival times in dry air at 35°C of adult male Drosophila melanogaster which had been irradiated when 2 days old with 35 krad ⁶⁰Co γ-rays were compared with those of unirradiated control flies. With increase in age survival times decreased for both control and irradiated flies, but until middle age the irradiated flies survived longer than the controls. In saturated air the controls had greater survival times than irradiated flies of the same age. It is concluded that the relative survival times in dry air were in part a reflection of differences in the abilities of flies to withstand desiccation and that the greater survival times of irradiated flies may have been due to factors such as lower activity which reduced the rate of water loss. The results are discussed in relation to theories of radiation-induced life-shortening and it is suggested that they are not incompatible with the theories which suggest that radiation may affect the natural ageing process.     

The effects of exogenous glutathione on reduced glutathione level, glutathione peroxidase and glutathione reductase activities of rats with different ages and gender after whole-body Γ-irradiation

Age-and gender-related changes on reduced glutathione (GSH) level, glutathione peroxidase (GPx) and glutathione reductase (GR) activities in the liver of rat exposed to different dose of whole-body g-ray irradiation were determined. In addition, the effect of administration of exogenous GSH on endogenous GSH levels, GPx and GR activities was investigated. For this aim, male and female rats aged 1 and 5 moths were divided into two groups as g-ray and g-ray+GSH. Both groups were again divided into four groups as irradiated with 2, 4, 6 and 8 Gy doses. GSH level and GPx activity did not change with age while GR activity was decreased with age. Gender-dependent changes in GPx and GR activities were observed, but GSH values were not affect by sex. GSH levels, GPx and GR activities were not observed dose-associated changes of g-irradiation. GSH level and GPx activity in the 8Gy group were increased by GSH. GR activities of old male rats were found to be increased by glutathione in the 6 and 8Gy groups. These results indicate that radiation and administration of exogenous GSH affect gender-and age-dependent GSH level, GPx and GR activities in the rats.