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1.
Juan P. Bolaños Simon J.R. Heales Stefan Peuchen Jane E. Barker John M. Land John B. Clark 《Free radical biology & medicine》1996,21(7):995-1001
In this study we have investigated the mechanisms leading to mitochondrial damage in cultured neurons following sustained exposure to nitric oxide. Thus, the effects upon neuronal mitochondrial respiratory chain complex activity and reduced glutathione concentration following exposure to either the nitric oxide donor, S-nitroso-N-acetylpenicillamine, or to nitric oxide releasing astrocytes were assessed. Incubation with S-nitroso-N-acetylpenicillamine (1 mM) for 24 h decreased neuronal glutathione concentration by 57%, and this effect was accompanied by a marked decrease of complex I (43%), complex II–III (63%), and complex IV (41%) activities. Incubation of neurons with the glutathione synthesis inhibitor, l-buthionine-[S,r]-sulfoximine caused a major depletion of neuronal glutathione (93%), an effect that was accompanied by a marked loss of complex II–III (60%) and complex IV (41%) activities, although complex I activity was only mildly decreased (34%). In an attempt to approach a more physiological situation, we studied the effects upon glutathione status and mitochondrial respiratory chain activity of neurons incubated in coculture with nitric oxide releasing astrocytes. Astrocytes were activated by incubation with lipopolysaccharide/interferon-γ for 18 h, thereby inducing nitric oxide synthase and, hence, a continuous release of nitric oxide. Coincubation for 24 h of activated astrocytes with neurons caused a limited loss of complex IV activity and had no effect on the activities of complexes I or II–III. However, neurons exposed to astrocytes had a 1.7-fold fold increase in glutathione concentration compared to neurons cultured alone. Under these coculture conditions, the neuronal ATP concentration was modestly reduced (14%). This loss of ATP was prevented by the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine. These results suggest that the neuronal mitochondrial respiratory chain is damaged by sustained exposure to nitric oxide and that reduced glutathione may be an important defence against such damage. 相似文献
2.
Our previous studies reveal that long-term exposure of ovariectomized rodents to d-galactose results in pathophysiologic alterations associated with Alzheimer’s disease. The current study was to address whether
mitochondrial dysfunction was involved in the pathogenesis of this model. Ovariectomized mice were administered intraperitoneally
with d-galctose (100 mg/kg body weight) once a day for 8 weeks. Brain tissues from model mice showed decreases in reduced glutathione
level, total antioxidative capabilities, total superoxide dismutase activity and glutathione peroxidase activity but an increase
in malondialdehyde level, compared with those from sham-operated plus saline-injected mice. Activities of brain mitochondrial
respiratory chain (complex I, II, III and IV) were reduced in model group. In contrast, ATP synthase (F1F0-ATPase) activity was not significantly different between the two groups. Moreover, electron microscopy identified ultrastructural
impairments of hippocampal mitochondria in model mice. These results demonstrated that brain mitochondrial degeneration caused
by oxidative stress participated in the etiology of ovarian hormone deprivation and d-galactose-induced neurodegeneration. 相似文献
3.
Agnieszka Ścibior Halina Zaporowska Agnieszka Wolińska Jarosław Ostrowski 《Cell biology and toxicology》2010,26(6):509-526
Selected biochemical parameters were studied in the blood of outbred, male Wistar rats which daily received to drink deionized
water (Group I, control) or solutions of: sodium metavanadate (SMV; 0.100 mg V/mL)—Group II; chromium chloride (CC; 0.004 mg
Cr/mL)—Group III; and SMV-CC (0.100 mg V and 0.004 mg Cr/mL)—Group IV for a 12-week period. The diet and fluid intake, body
weight gain, and food efficiency ratio (FER) diminished significantly in the rats of Groups II and IV, compared with Groups
I and III. The plasma total antioxidant status (TAS) as well as the MDA and the l-ascorbic acid level in the erythrocytes (RBCs) remained unchanged in all the groups, whereas the plasma l-ascorbic acid concentration decreased markedly in Group II, compared with Group III. The activities of Cu,Zn-superoxide dismutase
(Cu,Zn-SOD), catalase (CAT), cellular glutathione peroxidase (cGSH-Px), and glutathione reductase (GR) in RBCs remained unaltered
in all the treated rats. However, the activity of glutathione S-transferase (GST) and the content of reduced glutathione (GSH) in RBCs decreased and increased, respectively, in Groups II,
III, and IV, compared with Group I. A vanadium–chromium interaction which affected the GST activity was also found. To summarize,
SMV and CC administered separately or in combination in drinking water for 12 weeks did not alter either lipid peroxidation
(LPO) or the activities of Cu,Zn-SOD, CAT, cGSH-Px, and GR, which allows a conclusion that both metals in the doses ingested
did not reveal their pro-oxidant potential on RBCs. 相似文献
4.
Shi D Guo S Liao S Su R Guo M Liu N Li P Tang Z 《Biological trace element research》2012,145(3):312-317
To investigate the protection of selenium on hepatic mitochondrial functions, 90 7-day-old ducklings were randomly divided
into three groups (groups I–III). Group I was used as a blank control. Group II was administered with aflatoxin B1 (0.1 mg/kg body weight). Group III was administered with aflatoxin B1 (0.1 mg/kg body weight) plus selenium (sodium selenite, 1 mg/kg body weight). All treatments were given once daily for 21 days.
The results showed that the activities of hepatic mitochondrial complexes I–IV in group II ducklings significantly decreased
when compared with group I (P < 0.01). Furthermore, the activities of hepatic mitochondrial complexes I–IV in group III significantly increased when compared
with group II (P < 0.05). The hepatic mitochondrial respiratory control ratio (RCR) in group II ducklings significantly decreased when compared
with group I (P < 0.01). In addition, the hepatic mitochondrial RCR in group III significantly increased when compared with group II (P < 0.05). These results revealed that the aflatoxin B1 significantly induced hepatic mitochondrial dysfunction in the activities of hepatic mitochondrial respiratory chain complexes
I–IV and the RCR in ducklings. However, sodium selenite could significantly ameliorate the negative effect induced by aflatoxin
B1. 相似文献
5.
Neuronal Mitochondrial Toxicity of Malondialdehyde: Inhibitory Effects on Respiratory Function and Enzyme Activities in Rat Brain Mitochondria 总被引:1,自引:0,他引:1
Jiangang Long Changsheng Liu Lijuan Sun Hongxiang Gao Jiankang Liu 《Neurochemical research》2009,34(4):786-794
Malondialdehyde (MDA) is a product of oxidative damage to lipids, amino acids and DNA, and accumulates with aging and diseases.
MDA can possibly react with amines so as to modify proteins and inactivate enzymes; it can also modify nucleosides so as to
cause mutagenicity. Brain mitochondrial dysfunction is a major contributor to aging and neurodegenerative diseases. We hypothesize
that MDA accumulated during aging targets mitochondrial enzymes so as to cause further mitochondrial dysfunction and additional
contributions to aging and neurodegeneration. Herein, we investigated the neuronal mitochondrial toxic effects of MDA on mitochondrial
respiration and activities of enzymes (mitochondrial complexes I–V, α-ketoglutarate dehydrogenase (KGDH) and pyruvate dehydrogenase
(PDH)), in isolated rat brain mitochondria. MDA depressed mitochondrial membrane potential, and also showed a dose-dependent
inhibition of mitochondrial complex I- and complex II-linked respiration. Complex I and II, and PDH activities were depressed
by MDA at ≥0.2 μmol/mg; KGDH and complex V were inhibited by ≥0.4 and ≥1.6 μmol MDA/mg, respectively. However, MDA did not
have any toxic effects on complex III and IV activities over the range 0–2 μmol/mg. MDA significantly elevated mitochondrial
reactive oxygen species (ROS) and protein carbonyls at 0.2 and 0.002 μmol/mg, respectively. As for the antioxidant defense
system, a high dose of MDA slightly decreased mitochondrial GSH and superoxide dismutase. These results demonstrate that MDA
causes neuronal mitochondrial dysfunction by directly promoting generation of ROS and modifying mitochondrial proteins. The
results suggest that MDA-induced neuronal mitochondrial toxicity may be an important contributing factor to brain aging and
neurodegenerative diseases.
Special issue article in honor of Dr. Akitane Mori. 相似文献
6.
Mariona Guitart‐Mampel Diana L. Juarez‐Flores Lina Youssef Constanza Moren Laura Garcia‐Otero Vicente Roca‐Agujetas Marc Catalan‐Garcia Ingrid Gonzalez‐Casacuberta Ester Tobias Jos C. Milisenda Josep M. Grau Ftima Crispi Eduard Gratacos Francesc Cardellach Glria Garrabou 《Journal of cellular and molecular medicine》2019,23(6):3962-3973
Intrauterine growth restriction (IUGR) is an obstetric complication characterised by placental insufficiency and secondary cardiovascular remodelling that can lead to cardiomyopathy in adulthood. Despite its aetiology and potential therapeutics are poorly understood, bioenergetic deficits have been demonstrated in adverse foetal and cardiac development. We aimed to evaluate the role of mitochondria in human pregnancies with IUGR. In a single‐site, cross‐sectional and observational study, we included placenta and maternal peripheral and neonatal cord blood mononuclear cells (PBMC and CBMC) from 14 IUGR and 22 control pregnancies. The following mitochondrial measurements were assessed: enzymatic activities of mitochondrial respiratory chain (MRC) complexes I, II, IV, I + III and II + III, oxygen consumption (cell and complex I‐stimulated respiration), mitochondrial content (citrate synthase [CS] activity and mitochondrial DNA copy number), total ATP levels and lipid peroxidation. Sirtuin3 expression was evaluated as a potential regulator of bioenergetic imbalance. Intrauterine growth restriction placental tissue showed a significant decrease of MRC CI enzymatic activity (P < 0.05) and CI‐stimulated oxygen consumption (P < 0.05) accompanied by a significant increase of Sirtuin3/β‐actin protein levels (P < 0.05). Maternal PBMC and neonatal CBMC from IUGR patients presented a not significant decrease in oxygen consumption (cell and CI‐stimulated respiration) and MRC enzymatic activities (CII and CIV). Moreover, CS activity was significantly reduced in IUGR new‐borns (P < 0.05). Total ATP levels and lipid peroxidation were preserved in all the studied tissues. Altered mitochondrial function of IUGR is especially present at placental and neonatal level, conveying potential targets to modulate obstetric outcome through dietary interventions aimed to regulate Sirtuin3 function. 相似文献
7.
Effect of [6]-gingerol, a major pungent component in ginger, on the proliferation of a rat ascites hepatoma AH109A cells was
investigated by measuring [3H]thymidine incorporation into acid-insoluble fraction of the cultured cells and that on the invasion by co-culturing the
hepatoma cells with rat mesentery-derived mesothelial cells. [6]-Gingerol inhibited both the proliferation and invasion of
hepatoma cells in a dose-dependent manner at concentrations of 6.25–200 μM (proliferation) and 50–200 μM (invasion). [6]-Gingerol
accumulated cells in S phase and elongated doubling time of hepatoma cells, and increased the rate of apoptosis. Hepatoma
cells previously cultured with hypoxanthine (HX) and xanthine oxidase (XO) or with hydrogen peroxide showed increased invasive
activities. [6]-Gingerol suppressed the reactive oxygen species-potentiated invasive capacity by simultaneously treating AH109A
cells with [6]-gingerol, HX and XO or with [6]-gingerol and hydrogen peroxide. Furthermore, [6]-gingerol reduced the intracellular
peroxide levels in AH109A cells. These results suggest that the suppression of hepatoma cell proliferation by [6]-gingerol
may be due to cell cycle arrest and apoptosis induction. They also suggest that the anti-oxidative property of [6]-gingerol
may be involved in its anti-invasive activity of hepatoma cells. 相似文献
8.
9.
Roberto Federico Villa Antonella Gorini Siegfried Hoyer 《Neurochemical research》2009,34(12):2102-2116
The effect of ageing and the relationships between the catalytic properties of enzymes linked to Krebs’ cycle, electron transfer
chain, glutamate and aminoacid metabolism of cerebral cortex, a functional area very sensitive to both age and ischemia, were
studied on mitochondria of adult and aged rats, after complete ischemia of 15 minutes duration. The maximum rate (V
max) of the following enzyme activities: citrate synthase, malate dehydrogenase, succinate dehydrogenase for Krebs’ cycle; NADH-cytochrome
c reductase as total (integrated activity of Complex I–III), rotenone sensitive (Complex I) and cytochrome oxidase (Complex
IV) for electron transfer chain; glutamate dehydrogenase, glutamate–oxaloacetate- and glutamate–pyruvate transaminases for
glutamate metabolism were assayed in non-synaptic, perikaryal mitochondria and in two populations of intra-synaptic mitochondria,
i.e., the light and heavy mitochondrial fraction. The results indicate that in normal, steady-state cerebral cortex, the value
of the same enzyme activity markedly differs according (a) to the different populations of mitochondria, i.e., non-synaptic
or intra-synaptic light and heavy, (b) and respect to ageing. After 15 min of complete ischemia, the enzyme activities of
mitochondria located near the nucleus (perikaryal mitochondria) and in synaptic structures (intra-synaptic mitochondria) of the cerebral tissue were substantially
modified by ischemia. Non-synaptic mitochondria seem to be more affected by ischemia in adult and particularly in aged animals
than the intra-synaptic light and heavy mitochondria. The observed modifications in enzyme activities reflect the metabolic
state of the tissue at each specific experimental condition, as shown by comparative evaluation with respect to the content
of energy-linked metabolites and substrates. The derangements in enzyme activities due to ischemia is greater in aged than
in adult animals and especially the non-synaptic and the intra-synaptic light mitochondria seems to be more affected in aged
animals. These data allow the hypothesis that the observed modifications of catalytic activities in non-synaptic and intra-synaptic
mitochondrial enzyme systems linked to energy metabolism, amino acids and glutamate metabolism are primary responsible for
the physiopathological responses of cerebral tissue to complete cerebral ischemia for 15 min duration during ageing. 相似文献
10.
Ana Navarro Manuel J. Bández Carmen Gómez Marisa G. Repetto Alberto Boveris 《Journal of bioenergetics and biomembranes》2010,42(5):405-412
Rotenone and pyridaben were tested on activities and properties of rat brain mitochondria determining Ki (inhibitor concentration
at half maximal inhibition) and Imax (% of inhibition at maximal inhibitor concentration). The assayed activities were complexes
I, II and IV, respiration in states 3, 3u (uncoupled) and 4, biochemical and functional activities of mitochondrial nitric
oxide synthase (mtNOS), and inner membrane potential. Selective inhibitions of complex I activity, mitochondrial respiration
and membrane potential with malate-glutamate as substrate were observed, with a Ki of 0.28–0.36 nmol inhibitor/mg of mitochondrial
protein. Functional mtNOS activity was half-inhibited at 0.70–0.74 nmol inhibitor/mg protein in state 3 mitochondria and at
2.52–2.98 nmol inhibitor/mg protein in state 3u mitochondria. This fact is interpreted as an indication of mtNOS being structurally
adjacent to complex I with an intermolecular mtNOS-complex I hydrophobic bonding that is stronger at high Δψ and weaker at
low Δψ. 相似文献
11.
Exogenously applied ABA-β-d-glucopyranosyl ester (ABA-GE) inhibited shoot growth of alfalfa (Medicago sativa L.), cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), Digitaria sanguinalis L., timothy (Pheleum pratense L.) and ryegrass (Lolium multiflorum Lam.) seedlings at concentrations greater than 0.1 μM. The growth inhibitory activity of ABA-GE on these shoots was 26–40% of
that of (+)-ABA. ABA-β-d-glucosidase activities in these seedlings were 11–31 nmol mg−1 protein min−1. These results suggests that exogenously applied ABA-GE may be absorbed by plant roots and hydrolyzed by ABA-β-d-glucosidase, and liberated free ABA may induce the growth inhibition in these plants. Thus, although ABA-GE had been thought
to be physiologically inactive ABA conjugate, ABA-GE may have important physiological functions rather than an inactive conjugated
ABA form. 相似文献
12.
Ribeiro CA Sgaravatti AM Rosa RB Schuck PF Grando V Schmidt AL Ferreira GC Perry ML Dutra-Filho CS Wajner M 《Neurochemical research》2008,33(1):114-124
In the present work we investigated the in vitro effect of the branched-chain amino acids (BCAA) accumulating in maple syrup
urine disease (MSUD) on some parameters of energy metabolism in cerebral cortex of rats. 14CO2 production from [1-14C]acetate, [1-5-14C]citrate and [U-14C]glucose, as well as glucose uptake by the brain were evaluated by incubating cortical prisms from 30-day-old rats in the
absence (controls) or presence of leucine (Leu), valine (Val) or isoleucine (Ile). All amino acids significantly reduced 14CO2 production by around 20–55%, in contrast to glucose utilization, which was significantly increased by up to 90%. Furthermore,
Leu significantly inhibited the activity of the respiratory chain complex IV, whereas Val and Ile markedly inhibited complexes
II–III, III and IV by up to 40%. We also observed that trolox (α-tocopherol) and creatine totally prevented the inhibitory
effects provoked by the BCAA on the respiratory chain complex activities, suggesting that free radicals were involved in these
effects. The results indicate that the major metabolites accumulating in MSUD disturb brain aerobic metabolism by compromising
the citric acid cycle and the electron flow through the respiratory chain. We presume that these findings may be of relevance
to the understanding of the pathophysiology of the neurological dysfunction of MSUD patients. 相似文献
13.
Nakazawa H Okada K Kobayashi R Kubota T Onodera T Ochiai N Omata N Ogasawara W Okada H Morikawa Y 《Applied microbiology and biotechnology》2008,81(4):681-689
The genes encoding the catalytic domains (CD) of the three endoglucanases (EG I; Cel7B, EG II; Cel5A, and EG III; Cel12A)
from Trichoderma reesei QM9414 were expressed in Escherichia coli strains Rosetta-gami B (DE3) pLacI or Origami B (DE3) pLacI and were found to produce functional intracellular proteins.
Protein production by the three endoglucanase transformants was evaluated as a function of growth temperature. Maximal productivity
of EG I-CD at 15°C, EG II-CD at 20°C and EG III at 37°C resulted in yields of 6.9, 72, and 50 mg/l, respectively. The endoglucanases
were purified using a simple purification method based on removing E. coli proteins by isoelectric point precipitation. Specific activity toward carboxymethyl cellulose was found to be 65, 49, and
15 U/mg for EG I-CD, EG II-CD, and EG III, respectively. EG II-CD was able to cleave 1,3–1,4-β-d-glucan and soluble cellulose derivatives. EG III was found to be active against cellulose, 1,3–1,4-β-d-glucan and xyloglucan, while EG I-CD was active against cellulose, 1,3–1,4-β-d-glucan, xyloglucan, xylan, and mannan. 相似文献
14.
Ana O. Fagundes Giselli Scaini Patricia M. Santos Monique U. Sachet Nayara M. Bernhardt Gislaine T. Rezin Samira S. Valvassori Patrícia F. Schuck João Quevedo Emilio L. Streck 《Neurochemical research》2010,35(3):405-411
Methylphenidate (MPH) is frequently prescribed for the treatment of attention deficit/hyperactivity disorder. It was previously
demonstrated that MPH altered brain metabolic activity. Most cell energy is obtained through oxidative phosphorylation, in
the mitochondrial respiratory chain. However, there are still few studies about MPH effects on the brain of adult rats. Thus,
in the present study we evaluated the effect of acute or chronic administration of MPH on the activities of mitochondrial
respiratory chain complexes I–IV in the brain of adult rats. For acute administration, a single injection of MPH was given
to 60-day-old rats. For chronic administration, MPH injections were given to 60-day-old rats once daily for 28 days. Our results
showed that complexes I, II, III and IV were inhibited after acute or chronic MPH administration in the hippocampus, prefrontal
cortex, striatum and cerebral cortex. On the other hand, cerebellum was not affected. 相似文献
15.
Roemmich James N.; Clark Pamela A.; Weltman Arthur; Rogol Alan D. 《Journal of applied physiology》1997,83(3):927-935
Roemmich, James N., Pamela A. Clark, Arthur Weltman, andAlan D. Rogol. Alterations in growth and body composition duringpuberty. I. Comparing multicompartment body composition models.J. Appl. Physiol. 83(3): 927-935, 1997.A four-compartment (4C) model of body composition was used as acriterion to determine the accuracy of three-compartment (3C) andtwo-compartment (2C) models to estimate percent body fat (%BF) inprepubertal and pubertal boys (genital I & II,n = 17; genital III & IV,n = 7) and girls (breast I & II, n = 8; breast III & IV,n = 15). The 3C water-density (3C-H2O) and 3C mineral-densitymodels, dual-energy X-ray absorptiometry, the Lohman age-adjustedequations, the Slaughter et al. skinfold equations, and the Houtkooperet al. and Boileau bioelectrical impedance equations wereevaluated. Agreement with the 4C model increased with thenumber of compartments (i.e., body water, bone mineral) measured.Except for the 3C-H2O model, thelimits of agreement were large and did not perform well forindividuals. The mean %BF by dual-energy X-ray absorptiometry (23.6%)was greater than that of the criterion 4C method (21.7%).For the field methods, the Slaughter et al. skinfold equationsperformed better than did the Houtkooper et al. and Boileaubioimpedance equations. The hydration of the fat-free mass decreased(genital I & II = 75.7%, genital III & IV = 74.8%, breast I & II = 75.5%, breast III & IV = 74.4%) and the mineral content increased(genital I & II = 4.9%, genital III & IV = 5.0%, breast I & II = 5.1%, breast III & IV = 5.7%) with maturation. The densityof the fat-free mass also increased (genital I & II = 1.084 g/ml,genital III & IV = 1.087 g/ml, breast I & II = 1.086 g/ml, breast III & IV = 1.091 g/ml) with maturation. All of the models reduced the %BF overprediction of the Siri 2C model, but only the 4C and3C-H2O models should be used ascriterion methods for body composition validation in children andadolescents. 相似文献
16.
Zhiqiang Wu Guoliang Jiang 《International journal of peptide research and therapeutics》2008,14(2):75-80
Using N-α-benzoyl-l-arginine p-nitroanilide (BApNA) as substrate, trypsin-like enzymes (TLEs) were purified from mysis (Neomysis japonica) following two chromatographic steps, Sephacryl S100 HR gel filtration and Benzamidine-Sepharose 4B affinity. They presented
a high stability in the raw material, retaining over 45% of the initial activity after 30 days of storage at pH 8.0, 45 °C.
The purified TLEs had relative molecular mass between 32 kDa and 33 kDa. With higher stability and greater activity, they
had similar stability and activity profiles (pH 6.0–11.0, 15–65 °C) as bovine trypsin but had a different optimum temperature
(35 °C for trypsin and 45 °C for TLEs). Similar to bovine trypsin, the purified TLEs could be activated by Ca2+ and Mg2+. And the purified TLEs also showed similar inhibitory profiles as bovine trypsin with the exception of chicken egg ovomucoid
(CEOM), an effective inhibitor of bovine trypsin but less so for purified TLEs. Having TLEs with physiological efficiency
3.6 times that of bovine trypsin, the use of mysis as a source for commercial production of TLEs is discussed. 相似文献
17.
Temporal and Spatial Distribution of the nifH Gene of N2 Fixing Bacteria in Forests and Clearcuts in Western Oregon 总被引:1,自引:0,他引:1
Abstract
Decomposition of plant litter is a primary mechanism of nutrient recycling and redistribution in most terrestrial ecosystems.
Previously we demonstrated by a nested PCR protocol that 20 distinctive nifH (the gene encoding nitrogenase reductase) HaeIII restriction fragment length polymorphism (RFLP) patterns were derived from bulk DNA associated with samples of plant litter
and soil collected at one Douglas Fir (DF) forest [33]. Five of the nifH DNA patterns (II–VI) were dominant types in DF litter with characteristic fragments of 237–303 bp length, whereas samples
from soil contained primarily seven other patterns 131–188 bp length (IX–XV). Here we report that the 237–303 bp fragments
characteristic for forest litter could generally not be detected in plant litter or soil samples collected in clearcuts that
adjoin the forest sites. The same fragments (237–303 bp) were also found in the litter at this DF forest site over 16 months
and were consistently found in litter at 12 other DF forest or recent (<2 yrs) clearcut sites. However, trace to none of these
fragments were detected in 6 clearcut (5–10 yrs) or different forest types (oak, alder) collected over a 200 km east–west
direction in western Oregon, USA. Data suggest that the logging practice in DF forests that creates a clearcut removes a unique
gene pool of nitrogen-fixing microorganisms. These organisms could potentially contribute more to nitrogen fixation in forest
litter than litter from natural or invasive plants that grow in clearcuts [26].
Received: 1 June 1999; Accepted: 7 October 1999; Online Publication: 23 February 2000 相似文献
18.
Mitochondrial Calcium Transport and Mitochondrial Dysfunction After Global Brain Ischemia in Rat Hippocampus 总被引:1,自引:0,他引:1
Peter Racay Zuzana Tatarkova Maria Chomova Jozef Hatok Peter Kaplan Dusan Dobrota 《Neurochemical research》2009,34(8):1469-1478
Here we report effect of ischemia-reperfusion on mitochondrial Ca2+ uptake and activity of complexes I and IV in rat hippocampus. By performing 4-vessel occlusion model of global brain ischemia,
we observed that 15 min ischemia led to significant decrease of mitochondrial capacity to accumulate Ca2+ to 80.8% of control whereas rate of Ca2+ uptake was not significantly changed. Reperfusion did not significantly change mitochondrial Ca2+ transport. Ischemia induced progressive inhibition of complex I, affecting final electron transfer to decylubiquinone. Minimal
activity of complex I was observed 24 h after ischemia (63% of control). Inhibition of complex IV activity to 80.6% of control
was observed 1 h after ischemia. To explain the discrepancy between impact of ischemia on rate of Ca2+ uptake and activities of both complexes, we performed titration experiments to study relationship between inhibition of particular
complex and generation of mitochondrial transmembrane potential (ΔΨm). Generation of a threshold curves showed that complex I and IV activities must be decreased by approximately 40, and 60%,
respectively, before significant decline in ΔΨm was documented. Thus, mitochondrial Ca2+ uptake was not significantly affected by ischemia-reperfusion, apparently due to excess capacity of the complexes I and IV.
Inhibition of complex I is favourable of reactive oxygen species (ROS) generation. Maximal oxidative modification of membrane
proteins was documented 1 h after ischemia. Although enhanced formation of ROS might contribute to neuronal injury, depressed
activities of complex I and IV together with unaltered rate of Ca2+ uptake are conditions favourable of initiation of other cell degenerative pathways like opening of mitochondrial permeability
transition pore or apoptosis initiation, and might represent important mechanism of ischemic damage to neurones. 相似文献
19.
Qi Wang Cui Min Tingting Yan Hefang Pu Yinqiang Xin Shuangquan Zhang Lan Luo Zhimin Yin 《World journal of microbiology & biotechnology》2011,27(11):2603-2610
l-glutamine (Gln) is an important conditionally necessary amino acid in human body and potential demand in food or medicine
industry is expected. High efficiency of l-Gln production by coupling genetic engineered bacterial glutamine synthetase (GS) with yeast alcoholic fermentation system
has been developed. We report here first the application of small ubiquitin-related modifier (SUMO) fusion technology to the
expression and purification of recombinant Bacillus subtilis GS. In order to obtain GS with high Gln-forming activity, safety and low cost for food and pharmaceutics industry, 0.1% (w/v)
lactose was selected as inducer. The fusion protein was expressed in totally soluble form in E. coli, and expression was verified by SDS–PAGE and western blot analysis. The fusion protein was purified to 90% purity by nickel
nitrilo-triacetic acid (Ni–NTA) resin chromatography with a yield of 625 mg per liter fermentation culture. After the SUMO/GS
fusion protein was cleaved by the SUMO protease, the cleaved sample was reapplied to a Ni–NTA column. Finally, about 121 mg
recombinant GS was obtained from 1 l fermentation culture with no less than 96% purity. The recombinant purified GS showed
great transferase activity (23 U/mg), with 25 U recombinant GS in a 50 ml reaction system, a biosynthesis yield of 27.5 g/l l-Gln was detected by high pressure liquid chromatography (HPLC) or thin-layer chromatography. Thus, the application of SUMO
technology to the expression and purification of GS potentially could be employed for the industrial production of l-Gln. 相似文献
20.
Kuczer Mariola Rosiński Grzegorz Issberner Jonathan Osborne Richard Konopińska Danuta 《International journal of peptide research and therapeutics》1998,5(5-6):387-389
Summary We have extended our work on structure/activity relationship studies of the neuropeptiden proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH)
by evaluating the effects of the following proctolin analogues: H-X1-Tyr-Leu-Pro-Thr-OH, where X1=d-Arg(I),N-Me-Arg (II), Can (III), Orn(di-Me) (IV), Orn (iPr) (V), Lys(N, N-di-Me) (VI), Lys(iPr) (VII), Lys(Nic) (VIII) andd-Lys(Nic) (IX). In analogues I–IX, the N-terminal Arg residue was replaced by basic amino acid derivatives with peptides containing
amino acid residues with an isosteric system on the back side chain relative to Arg (compounds III, V and VI) orhomo-Arg (compound VII). Analogues I–IX were evaluated for myotropic activity on thein vitro heart preparation ofTenebrio molitor, whereas peptides II, V, and VII–IX were tested for contractile activity on the isolated foregut of locustSchistocerca gregaria. Peptide II and III showed full cardiotropic activity inT. molitor while peptides V and VII showed 40% and 15%, respectively, locust-gut contracting activity of proctolin. 相似文献