Electron Transport System Enzymes Research Articles

Abstract P1095: Studying Changes In Mitochondrial Dynamics And Energetics During Cardiac Reprogramming

In mammals, cardiac ischemic injury leads to loss of muscle filled in with less functional scar tissue. Direct reprogramming of the cardiac fibroblasts populating a scar to functional cardiomyocytes represents a promising potential treatment for these patients. This reprogramming involves a metabolic shift from the more glycolytic CF state to mitochondrial oxidative phosphorylation in the induced CMs, including increased mitochondrial biogenesis. Various reprogramming strategies make use of agents, which in addition to canonical roles, promote mitochondrial energetics and a dynamic shift towards mitochondrial fusion. We decided to investigate whether these mitochondrial structural and functional shifts might represent a mechanism of reprogramming. We characterized various structural and energetic properties of mitochondria in neonatal CFs, CMs, and at multiple time points during reprogramming. Using the baseline CF and CM mitochondrial data, we built a model to follow cells in pseudotime during reprogramming, and identified a time course for mitochondrial changes. We also investigated whether various mitochondrial perturbations designed to promote these changes might increase reprogramming efficiency. Promotion of mitochondrial fusion activity and biogenesis increased the proportion of reprogrammed cells. Conversely, promotion of fission and inhibitors for electron transport system enzymes inhibited reprogramming.

Thermal modulation of mitochondrial function is affected by environmental nickel in rainbow trout (Oncorhynchus mykiss)

In this study, we investigated the combined effects of temperature and nickel (Ni) contamination on liver mitochondria electron transport system (ETS) enzymes, citrate synthase (CS), phospholipid fatty acid composition and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). Juvenile trout were acclimated for two weeks to two different temperatures (5˚C and 15˚C) and exposed to nickel (Ni; 520 μg/L) for three weeks. Using ratios of ETS enzymes and CS activities, our data suggest that Ni and an elevated temperature acted synergistically to induce a higher capacity for reduction status of the ETS. The response of phospholipid fatty acid profiles to thermal variation was also altered under nickel exposure. In control conditions, the proportion of saturated fatty acids (SFA) was higher at 15˚C than at 5˚C, while the opposite was observed for monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). However, in nickel contaminated fish, the proportion of SFA was higher at 5˚C than at 15˚C, while PUFA and MUFA followed the opposite direction. A higher PUFA ratio is associated with higher vulnerability to lipid peroxidation. Thiobarbituric Acid Reactive Substances (TBARS) content was higher when the PUFA were in higher proportions, except for Ni-exposed, warm-acclimated fish, in which we reported the lowest level of TBARS but the highest proportion of PUFA. We suspect that the interaction of nickel and temperature on lipid peroxidation is due to their synergistic effects on aerobic energy metabolism, as supported by the decrease in the activity of complex IV of the ETS enzyme activity in those fish, or on antioxidant enzymes and pathways. Overall, our study demonstrates that Ni exposure in heat-challenged fish can lead to the remodelling of the mitochondrial phenotype and potentially stimulate alternative antioxidant mechanisms.

Modulation of mitochondrial site-specific hydrogen peroxide efflux by exogenous stressors

Oxygen (O2) deprivation and metals are common environmental stressors and their exposure to aquatic organisms can induce oxidative stress by disrupting cellular reactive oxygen species (ROS) homeostasis. Mitochondria are a major source of ROS in the cell wherein a dozen sites located on enzymes of the electron transport system (ETS) and substrate oxidation produce superoxide anion radicals (O2˙‾) or hydrogen peroxide (H2O2). Sites located on ETS enzymes can generate ROS by forward electron transfer (FET) and reverse electron transfer (RET) reactions; however, knowledge of how exogenous stressors modulate site-specific ROS production is limited. We investigated the effects of anoxia-reoxygenation and cadmium (Cd) on H2O2 emission in fish liver mitochondria oxidizing glutamate-malate, succinate or palmitoylcarnitine-malate. We find that anoxia-reoxygenation attenuates H2O2 emission while the effect of Cd depends on the substrate, with monotonic responses for glutamate-malate and palmitoylcarnitine-malate, and a biphasic response for succinate. Anoxia-reoxygenation exerts a substrate-dependent inhibition of mitochondrial respiration which is more severe with palmitoylcarnitine-malate compared with succinate or glutamate-malate. Additionally, specific mitochondrial ROS-emitting sites were sequestered using blockers of electron transfer and the effects of anoxia-reoxygenation and Cd on H2O2 emission were evaluated. Here, we find that site-specific H2O2 emission capacities depend on the substrate and the direction of electron flow. Moreover, anoxia-reoxygenation alters site-specific H2O2 emission rates during succinate and glutamate-malate oxidation whereas Cd imposes monotonic or biphasic H2O2 emission responses depending on the substrate and site. Contrary to our expectation, anoxia-reoxygenation blunts the effect of Cd. These results suggest that the effect of exogenous stressors on mitochondrial oxidant production is governed by their impact on energy conversion reactions and mitochondrial redox poise. Moreover, direct increased ROS production seemingly does not explain the increased adverse effects associated with combined exposure of aquatic organisms to Cd and low dissolved oxygen levels.

Mitochondrial Traits Previously Associated With Species Maximum Lifespan Do Not Correlate With Longevity Across Populations of the Bivalve Arctica islandica.

The mitochondrial oxidative stress theory of aging posits that membrane susceptibility to peroxidation and the organization of the electron transport system (ETS) linked with reactive oxygen species (ROS) generation are two main drivers of lifespan. While a clear correlation has been established from species comparative studies, the significance of these characteristics as potential modulators of lifespan divergences among populations of individual species is still to be tested. The bivalve Arctica islandica, the longest-lived non-colonial animal with a record lifespan of 507 years, possesses a lower mitochondrial peroxidation index (PI) and reduced H2O2 efflux linked to complexes I and III activities than related species. Taking advantage of the wide variation in maximum reported longevities (MRL) among 6 European populations (36–507 years), we examined whether these two mitochondrial properties could explain differences in longevity. We report no relationship between membrane PI and MRL in populations of A. islandica, as well as a lack of intraspecific relationship between ETS complex activities and MRL. Individuals from brackish sites characterized by wide temperature and salinity windows had, however, markedly lower ETS enzyme activities relative to citrate synthase activity. Our results highlight environment-dependent remodeling of mitochondrial phenotypes.

Uremic metabolites impair skeletal muscle mitochondrial energetics through disruption of the electron transport system and matrix dehydrogenase activity.

Chronic kidney disease (CKD) leads to increased skeletal muscle fatigue, weakness, and atrophy. Previous work has implicated mitochondria within the skeletal muscle as a mediator of muscle dysfunction in CKD; however, the mechanisms underlying mitochondrial dysfunction in CKD are not entirely known. The purpose of this study was to define the impact of uremic metabolites on mitochondrial energetics. Skeletal muscle mitochondria were isolated from C57BL/6N mice and exposed to vehicle (DMSO) or varying concentrations of uremic metabolites: indoxyl sulfate, indole-3-acetic-acid, l-kynurenine, and kynurenic acid. A comprehensive mitochondrial phenotyping platform that included assessments of mitochondrial oxidative phosphorylation (OXPHOS) conductance and respiratory capacity, hydrogen peroxide production (JH2O2), matrix dehydrogenase activity, electron transport system enzyme activity, and ATP synthase activity was employed. Uremic metabolite exposure resulted in a ~25-40% decrease in OXPHOS conductance across multiple substrate conditions (P < 0.05, n = 5-6/condition), as well as decreased ADP-stimulated and uncoupled respiratory capacity. ATP synthase activity was not impacted by uremic metabolites; however, a screen of matrix dehydrogenases indicated that malate and glutamate dehydrogenases were impaired by some, but not all, uremic metabolites. Assessments of electron transport system enzymes indicated that uremic metabolites significantly impair complex III and IV. Uremic metabolites resulted in increased JH2O2 under glutamate/malate, pyruvate/malate, and succinate conditions across multiple levels of energy demand (all P < 0.05, n = 4/group). Disruption of mitochondrial OXPHOS was confirmed by decreased respiratory capacity and elevated superoxide production in cultured myotubes. These findings provide direct evidence that uremic metabolites negatively impact skeletal muscle mitochondrial energetics, resulting in decreased energy transfer, impaired complex III and IV enzyme activity, and elevated oxidant production.

Neuromodulatory effect of solvent fractions of Africa eggplant (Solanium dadyphyllum) against KCN-induced mitochondria damage, viz. NADH-succinate dehydrogenase, NADH- cytochrome c reductase, and succinate-cytochrome c reductase

BackgroundIn the past few years, there has been a tremendous increase in the number of plant-based health supplements with respect to their safety and efficacy in diseases treatment and prevention. Solanum dasyphyllum, also known as Africa eggplant is ethnomedicinally used as an antivenom, pain reliever and anticonvulsant in various part of Nigeria, however, there is no scientific data to support some of these claims.MethodsThis study evaluated the protective effect of solvent fractions of Solanum dasyphyllum, hexane fraction of S. dasyphyllum (HFSD), dichloromethane fraction of S. dasyphyllum (DFSD), ethylacetate fraction of S. dasyphyllum (EAFSD), methanolic fraction of S. dasyphyllum (MFSD) and crude fraction of S. dasyphyllum (CFSD) on cyanide-induced oxidative stress and neurotoxicity in vitro in the cerebral cortex. Neuroprotective activities were evaluated by assaying for markers of oxidative stress, neurotoxicity and electron transport system enzymes via evaluating lipid peroxidation (LPO), protein carbonyl (PC), reduced glutathione (GSH), acetylcholinesterase (AChE), NADH-succinate dehydrogenase (NSD), NADH-cytochrome c reductase (NCR), and succinate-cytochrome c reductase (SCR) in the homogenate of cerebral cortex.ResultsThe results showed that all solvent fractions of S. dasyphyllum significantly ameliorated cyanide-induced oxidative stress (P < 0.05). It inhibited the activity of acetylcholinesterase-HFSD (68.42 ± 5.37%), DFSD (36.32 ± 5.45%), EFA (20 ± 0.69%), MFSD (33.16 ± 4.8%) and CFSD (35.79 ± 2.8%), increased the activity of NSD [HFSD (94.74 ± 7.3%), EAFSD (78.95 ± 5.4%) and CFSD (60.53 ± 4.6%)], while DFSD (− 5.26 ± 1.4%) and MFSD (− 7.9 ± 0.4%) had a negative effect, increased the activity of NCR [HFSD (91.89 ± 7.1%), DFSD (90.54 ± 8.2%), EAFSD (62.16 ± 4.7%); MFSD (306.76 ± 7.2%) and CFSD (154.0 ± 8.1%)]. All the solvent fractions also significantly increased the activity of SCR [HFSD (70.59 ± 3.8%), EAFSD (58.82 ± 6.4%), MFSD (88.24 ± 9.0%) CFSD (76.47 ± 8.2%)] apart from DFSD (− 5.88 ± 1.2%) in rat cerebral cortex.ConclusionThis result shows that S. dasyphyllum has neuroprotective activities, however HFSD shows the most potent bioactivities in maintaining mitochondria integrity by preserving the electron transport system. Further work can be done on isolating and characterizing the bioactive compound in HFSD for novel natural product in the treatment of neurological disorders.

Reversible temperature-dependent differences in brown adipose tissue respiration during torpor in a mammalian hibernator

Although seasonal modifications of brown adipose tissue (BAT) in hibernators are well documented, we know little about functional regulation of BAT in different phases of hibernation. In the 13-lined ground squirrel, liver mitochondrial respiration is suppressed by up to 70% during torpor. This suppression is reversed during arousal and interbout euthermia (IBE), and corresponds with patterns of maximal activities of electron transport system (ETS) enzymes. Uncoupling of BAT mitochondria is controlled by free fatty acid release stimulated by sympathetic activation of adipocytes, so we hypothesized that further regulation at the level of the ETS would be of little advantage. As predicted, maximal ETS enzyme activities of isolated BAT mitochondria did not differ between torpor and IBE. In contrast to this pattern, respiration rates of mitochondria isolated from torpid individuals were suppressed by ~60% compared with rates from IBE individuals when measured at 37°C. At 10°C, however, mitochondrial respiration rates tended to be greater in torpor than IBE. As a result, the temperature sensitivity (Q10) of mitochondrial respiration was significantly lower in torpor (~1.4) than IBE (~2.4), perhaps facilitating energy savings during entrance into torpor and thermogenesis at low body temperatures. Despite the observed differences in isolated mitochondria, norepinephrine-stimulated respiration rates of isolated BAT adipocytes did not differ between torpor and IBE, perhaps because the adipocyte isolation requires lengthy incubation at 37°C, potentially reversing any changes that occur in torpor. Such changes may include remodeling of BAT mitochondrial membrane phospholipids, which could change in situ enzyme activities and temperature sensitivities.

Regulation of mitochondrial metabolism during hibernation by reversible suppression of electron transport system enzymes.

Small hibernators cycle between periods of torpor, with body temperature (T b) approximately 5°C, and interbout euthermia (IBE), where T b is approximately 37°C. During entrance into a torpor bout liver mitochondrial respiration is rapidly suppressed by 70% relative to IBE. We compared activities of electron transport system (ETS) complexes in intact liver mitochondria isolated from 13-lined ground squirrels (Ictidomys tridecemlineatus) sampled during torpor and IBE to investigate potential sites of this reversible metabolic suppression. Flux through complexes I-IV and II-IV was suppressed by 40 and 60%, respectively, in torpor, while flux through complexes III-IV and IV did not differ between torpor and IBE. We also measured maximal enzyme activity of ETS enzymes in homogenized isolated mitochondria and whole liver tissue. In isolated mitochondria, activities of complexes I and II were significantly lower in torpor relative to IBE, but complexes III, IV, and V did not differ. In liver tissue, only activity of complex II was suppressed during torpor relative to IBE. Despite the significant differences in both ETS flux and maximal activity, the protein content of complexes I and II did not differ between torpor and IBE. These results suggest that the rapid, reversible suppression of mitochondrial metabolism is due to regulatory changes, perhaps by post-translational modification during entrance into a torpor bout, and not changes in ETS protein content.

Copper and hypoxia modulate transcriptional and mitochondrial functional-biochemical responses in warm acclimated rainbow trout (Oncorhynchus mykiss)

To survive in changing environments fish utilize a wide range of biological responses that require energy. We examined the effect of warm acclimation on the electron transport system (ETS) enzymes and transcriptional responses to hypoxia and copper (Cu) exposure in fish. Rainbow trout (Oncorhynchus mykiss) were acclimated to cold (11 °C; control) and warm (20 °C) temperatures for 3 weeks followed by exposure to Cu, hypoxia or both for 24 h. Activities of ETS enzyme complexes I-IV (CI–CIV) were measured in liver and gill mitochondria. Analyses of transcripts encoding for proteins involved in mitochondrial respiration (cytochrome c oxidase subunits 4-1 and 2: COX4-1 and COX4-2), metal detoxification/stress response (metallothioneins A and B: MT-A and MT-B) and energy sensing (AMP-activated protein kinase α1: AMPKα1) were done in liver mitochondria, and in whole liver and gill tissues by RT-qPCR. Warm acclimation inhibited activities of ETS enzymes while effects of Cu and hypoxia depended on the enzyme and thermal acclimation status. The genes encoding for COX4-1, COX4-2, MT-A, MT-B and AMPKα1 were strongly and tissue-dependently altered by warm acclimation. While Cu and hypoxia clearly increased MT-A and MT-B transcript levels in all tissues, their effects on COX4-1, COX4-2 and AMPKα1 mRNA levels were less pronounced. Importantly, warm acclimation differentially altered COX4-2/COX4-1 ratio in liver mitochondria and gill tissue. The three stressors showed both independent and joint actions on activities of ETS enzymes and transcription of genes involved in energy metabolism, stress response and metals homeostasis. Overall, we unveiled novel interactive effects that should not be overlooked in real world situations wherein fish normally encounter multiple stress factors.

Thermal sensitivity and phenotypic plasticity of cardiac mitochondrial metabolism in European perch, Perca fluviatilis.

Cellular and mitochondrial metabolic capacity of the heart has been suggested to limit performance of fish at warm temperatures. We investigated this hypothesis by studying the effects of acute temperature increases (16, 23, 30, 32.5 and 36°C) on the thermal sensitivity of 10 key enzymes governing cardiac oxidative and glycolytic metabolism in two populations of European perch (Perca fluviatilis) field-acclimated to 15.5 and 22.5°C, as well as the effects of acclimation on cardiac lipid composition. In both populations of perch, the activity of glycolytic (pyruvate kinase and lactate dehydrogenase) and tricarboxylic acid cycle (pyruvate dehydrogenase and citrate synthase) enzymes increased with acute warming. However, at temperatures exceeding 30°C, a drastic thermally induced decline in citrate synthase activity was observed in the cold- and warm-acclimated populations, respectively, indicating a bottleneck for producing the reducing equivalents required for oxidative phosphorylation. Yet, the increase in aspartate aminotransferase and malate dehydrogenase activities occurring in both populations at temperatures exceeding 30°C suggests that the malate-aspartate shuttle may help to maintain cardiac oxidative capacities at high temperatures. Warm acclimation resulted in a reorganization of the lipid profile, a general depression of enzymatic activity and an increased fatty acid metabolism and oxidative capacity. Although these compensatory mechanisms may help to maintain cardiac energy production at high temperatures, the activity of the electron transport system enzymes, such as complexes I and IV, declined at 36°C in both populations, indicating a thermal limit of oxidative phosphorylation capacity in the heart of European perch.

Organic matter of the Kiziltashskie Limans

Data on biochemical ecosystem monitoring of Kiziltashskie Limans are given. The limans are the only natural water bodies in the Russian Black Sea where pascual breeding of very valuable commercial fish is implemented. The presented concentrations of dissolved and particulate organic matter are 2–5 times greater than the values typical of the coastal zone of the Black Sea (from 7.9 to 27.7 mg/L and from 0.3 to 1.5 mg/L, respectively). The main biochemical component of the dissolved organic matter is carbohydrates, and that of particulate matter is protein. The share of particulate organic matter in the Kiziltashskie Limans never exceeds 7%. The elemental (C, N, P) and biochemical composition of organic matter is studied (carbohydrates, proteins, lipids). The rates of enzymatic reactions vary from season to season. Thus, processes of hydrolytic splitting of phosphor-organic compounds during primary production are very intensive in the spring, while processes of organic matter oxidation, catalyzed by enzymes of electron-transport system, are intensive in the summer.

The Effect of Iron and Copper as an Essential Nutrient on Mitochondrial Electron Transport System and Lipid Peroxidation in Trichoderma harzianum

Iron and copper are essential nutrients for all living organisms as cofactors of many enzymes and play important roles in electron transport system (ETS) enzymes which have heme and iron-sulfur centers. In the present study, ETS enzymes, namely, succinate dehydrogenase (SDH) and cytochrome c oxidase (COX), activities as well as adenine nucleotides and lipid peroxidation (LPO) levels of eukaryotic model Trichoderma harzianum grown in varied concentrations of iron (0-20 mg/l) and copper (0-25 mg/l) mediums have been examined. SDH and COX activities increased up to 10 mg/l of iron. COX and SDH activities increased significantly up to 15 and 1 mg/l of copper, respectively. ATP and ADP levels showed a positive correlation with SDH activity with respect to iron-copper concentrations. The trends of AMP were similar with those of ATP and ADP for iron concentrations, while AMP levels elevated until 5 mg/l of copper. As an indicative marker of membrane damage, LPO levels increased with iron and copper concentration. In conclusion, iron and copper concentrations are of critical importance on activities of the ETS enzymes besides adenine nucleotides and LPO levels by maintenance of this metal homeostasis.

Respiratory electron transport system activity in symbiotic corals and its link to calcification

Scleractinian corals host photosynthetic endosymbionts, making direct measurement of the host respiration rate via incubation methods based on O2 consumption impossible. We tested the use of the respiratory electron transport system activity (ETSA) for measuring host potential respiration. The applied method, modified from a previous study, is based on the re - duction of (4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) to formazan. After the development of a protocol suitable for corals, the method was tested on 5 different spe- cies. Metabolism, including photosynthesis, dark respiration and light and dark calcification, was measured through incubation. Host and zooxanthellae fractions were separated and their ETSAs, protein contents and zooxanthellae densities were measured. Mean ETSA/dark respiration (ETSA/R) ratios for host corals ranged from 1.7 ± 0.2 to 3.5 ± 0.6, while ratios for zooxanthellae ranged from 3.7 to 7.8. The high ratios observed for zooxanthellae indicate that their respiration may be 5 times higher under light conditions than in the dark. Considering the obtained ratios, host respiration in light could increase at most by a factor of 3.5 compared with dark respiration rates. Ratios close to 1 were found for some specimens, which suggests that higher respiration rates under light compared with dark conditions are not possible. Therefore, increased respiration in light cannot explain the observed enhancement of calcification under light conditions. ETSA was correlated with zooxanthellae density, suggesting adaptation of the levels of host ETS enzymes to the amount of translocated photosynthetates under optimal conditions. Estimated dark host respiration was correlated with photosynthesis, which suggests that it is determined mainly by the amount of energy available but also the amount of electron transport system enzymes. This constrains the amount of ATP available for calcification. Hence, we propose a mechanism by which respiration limits the calcification rate.

The investigation of the organophosphate pesticide bromopropylate effect on electron transport system enzymes and lipid peroxidation levels in Trichoderma harzianum

The investigation of the organophosphate pesticide bromopropylate effect on electron transport system enzymes and lipid peroxidation levels in Trichoderma harzianum

Cellular adaptation contributes to calorie restriction-induced preservation of skeletal muscle in aged rhesus monkeys

We have previously shown that a 30% reduced calorie intake diet delayed the onset of muscle mass loss in adult monkeys between ~16 and ~22years of age and prevented multiple cellular phenotypes of aging. In the present study we show the impact of long term (~17years) calorie restriction (CR) on muscle aging in very old monkeys (27–33yrs) compared to age-matched Control monkeys fed ad libitum, and describe these data in the context of the whole longitudinal study. Muscle mass was preserved in very old calorie restricted (CR) monkeys compared to age-matched Controls. Immunohistochemical analysis revealed an age-associated increase in the proportion of Type I fibers in the VL from Control animals that was prevented with CR. The cross sectional area (CSA) of Type II fibers was reduced in old CR animals compared to earlier time points (16–22years of age); however, the total loss in CSA was only 15% in CR animals compared to 36% in old Controls at ~27years of age. Atrophy was not detected in Type I fibers from either group. Notably, Type I fiber CSA was ~1.6 fold greater in VL from CR animals compared to Control animals at ~27years of age. The frequency of VL muscle fibers with defects in mitochondrial electron transport system enzymes (ETSab), the absence of cytochrome c oxidase and hyper-reactive succinate dehydrogenase, were identical between Control and CR. We describe changes in ETSab fiber CSA and determined that CR fibers respond differently to the challenge of mitochondrial deficiency. Fiber counts of intact rectus femoris muscles revealed that muscle fiber density was preserved in old CR animals. We suggest that muscle fibers from CR animals are better poised to endure and adapt to changes in muscle mass than those of Control animals.

The rates of organic matter destruction in the central part of the Arctic Basin

The intensity of the processes of organic matter (OM) destruction in the deep-water part of the Arctic Basin is considered in terms of the activities of hydrolytic enzymes (alkaline phosphatase and proteases) and of redox enzymes of the electron transport system (ETS). High concentrations of mineral phosphorus are shown to cause low phosphatase activity (0.000–0.005 μM P/l h). The average time of the phosphate recycling amounted to about 240 h. The ranges of the total and specific activity of protease are 0.000–0.192 mg of azocasein/(l h) and 0.00–3.57 mg of azocasein/h mg of protein, respectively. It is found that the microplankton production of exo- and endopeptidase in the Arctic Basin is controlled by the concentration of nitrates in the water. The values of the total and the specific activities of the ETS enzymes vary within 0.27–8.96 μl O2/(l h) and 8.4–583 μl O2/mg of protein h, respectively. It is shown that the maximum values of the total activities of the hydrolytic and redox enzymes are characteristic for the photic layer. The vertical fluxes of organic carbon from the photic layer, being calculated by the activity of the ETS enzymes, amounted to 220–600 g of Corg/year m2. The presence of ice intensifies the redox processes by factors of 2–15.

Mechanisms of Anti-Cancer Effects of &lt;i&gt;Vernonia amygdalina&lt;/i&gt; Leaf Extract

Problem statement: Vernonia amygdalina (V. amygdalina) has been shown to have cancer cell inhibition and cytotoxic effects. Approach: This study discusses the multi-faceted and multi-linked mechanisms by which cancer tissue inhibition and destruction is achieved by V. amygdalina leaf extract and powder (subsequently called V. amygdalina Extract). Cancer cell inhibition by V. amygdalina is suggested to occur through inhibition of sterol 14-α-demethylase, a microsomal P450-dependent enzyme system) of the membrane of the cancer cell. Inhibition of this enzyme impairs the biosynthesis of ergosterol for the cytoplasmic membrane. Results: This impairment of the synthesis of ergosterol disrupts the close packing of acyl chains of phospholipids and impairs the function of some membrane-bound enzyme systems like ATPase and enzymes of electron-transport system of the cancer cells. V. amygdalina extract inhibits sterol 14-α-demethylase by acting on β3 adrenergic receptors of the cancer cell membranes as a primary ligand in Gi (inhibitory) receptors on cancer β3 lipid cell membrane receptors and mitochondrial ATP energy generation system receptors. Conclusion: By effecting β-oxidation of fatty acids and lipids in cell membranes and cell mitochondrial energy (ATP) generation systems, the V. amygdalina extract uncouples the mitochondrial energy (ATP generation) systems of the cancer cells and cell membranes resulting in the cancer cells being burnt out (consumed) by the extract (when V. amygdalina extract is cytotoxic to the cancer cells) or its functioning being inhibited (when V. amygdalina extract is only inhibitory to the cancer cells.

Caloric restriction delays aging-induced cellular phenotypes in rhesus monkey skeletal muscle

Sarcopenia is the age-related loss of skeletal muscle mass and function and is characterized by a reduction in muscle mass and fiber cross-sectional area, alterations in muscle fiber type and mitochondrial functional changes. In rhesus monkeys, calorie restriction (CR) without malnutrition improves survival and delays the onset of age-associated diseases and disorders including sarcopenia. We present a longitudinal study on the impact of CR on early stage sarcopenia in the upper leg of monkeys from ~ 16 years to ~ 22 years of age. Using dual-energy X-ray absorptiometry we show that CR delayed the development of maximum muscle mass and, unlike Control animals, muscle mass of the upper leg was preserved in CR animals during early phase sarcopenia. Histochemical analyses of vastus lateralis muscle biopsies revealed that CR opposed age-related changes in the proportion of Type II muscle fibers and fiber cross-sectional area. In contrast the number of muscle fibers with mitochondrial electron transport system enzyme abnormalities (ETS ab) was not significantly affected by CR. Laser capture microdissection of ETS ab fibers and subsequent PCR analysis of the mitochondrial DNA revealed large deletion mutations in fibers with abnormal mitochondrial enzyme activities. CR did not prevent stochastic mitochondrial deletion mutations in muscle fibers but CR may have contributed to the maintenance of affected fibers.

Spatial-temporal variations in organic matter of the Sea of Azov

The spatial-temporal variations in the amount and biochemical composition of organic matter and the rates of its transformations in the ecosystems of the Russian part of the Sea of Azov are analyzed. Maximum OM concentrations are typical for Taganrog Bay. A characteristic feature of the Sea of Azov is a large proportion of particulate organic matter, which in summer in Taganrog Bay exceeded 35%. It is shown that not only the concentration of organic matter changes from season to season, but also its elementary (Corg, Norg, and Porg) and biochemical composition (proteins, carbohydrates, and lipids). The major biochemical compound of dissolved organic matter is shown to be carbohydrates (13–28%), and that of particulate matter is protein (44–51%). The hydrolytic (phosphatase and protease) and oxidation-reduction enzymes of electron-transport system demonstrate a high activity in summer. The estimated short turnover times of phosphates and protein suggest the rapid and complete utilization of organic matter in the Sea of Azov.

DISRUPTION OF MITOCHONDRIAL FUNCTION IN INTERPOPULATION HYBRIDS OF TIGRIOPUS CALIFORNICUS

Electron transport system (ETS) function in mitochondria is essential for the aerobic production of energy. Because ETS function requires extensive interactions between mitochondrial and nuclear gene products, coadaptation between mitochondrial and nuclear genomes may evolve within populations. Hybridization between allopatric populations may then expose functional incompatibilities between genomes that have not coevolved. The intertidal copepod Tigriopus californicus has high levels of nucleotide divergence among populations at mitochondrial loci and suffers F2 hybrid breakdown in interpopulation hybrids. We hypothesize that hybridization results in incompatibilities among subunits in ETS enzyme complexes and that these incompatibilities result in diminished mitochondrial function and fitness. To test this hypothesis, we measured fitness, mitochondrial function, and ETS enzyme activity in inbred recombinant hybrid lines of Tigriopus californicus. We found that (1) both fitness and mitochondrial function are reduced in hybrid lines, (2) only those ETS enzymes with both nuclear and mitochondrial subunits show a loss of activity in hybrid lines, and (3) positive relationships exist between ETS enzyme activity and mitochondrial function and between mitochondrial function and fitness. We also present evidence that hybrid lines harboring mitochondrial DNA (mtDNA) and mitochondrial RNA polymerase (mtRPOL) from the same parental source population have higher fitness than those with mtDNA and mtRPOL from different populations, suggesting that mitochondrial gene regulation may play a role in disruption of mitochondrial performance and fitness of hybrids. These results suggest that disruption of coadaptation between nuclear and mitochondrial genes contributes to the phenomenon of hybrid breakdown.