196 research outputs found
Iron–sulfur clusters/semiquinones in Complex I
AbstractNADH-quinone1Bovine heart Complex I contains only ubiquinone-10. Quinones in bacterial membranes differ depending on strains, for example, ubiquinone-10 in R. capsulatus; ubiquinone-8 in P.denitrificans; menaquinone-8 in T. thermophilus; both ubiquinone-8 and menaquinone-8 in aerobically grown E. coli cells (the ratio of UQ and MQ is controlled by oxygen tension). Therefore, in this mini-review, quinone (Q), quinol (QH2), and semiquinone (SQ) were used for simplicity.1 oxidoreductase (Complex I) isolated from bovine heart mitochondria was, until recently, the major source for the study of this most complicated energy transducing device in the mitochondrial respiratory chain. Complex I has been shown to contain 43 subunits and possesses a molecular mass of about 1 million. Recently, Complex I genes have been cloned and sequenced from several bacterial sources including Escherichia coli, Paracoccus denitrificans, Rhodobacter capsulatus and Thermus thermophilus HB-8. These enzymes are less complicated than the bovine enzyme, containing a core of 13 or 14 subunits homologous to the bovine heart Complex I. From this data, important clues concerning the subunit location of both the substrate binding site and intrinsic redox centers have been gleaned. Powerful molecular genetic approaches used in these bacterial systems can identify structure/function relationships concerning the redox components of Complex I. Site-directed mutants at the level of bacterial chromosomes and over-expression and purification of single subunits have allowed detailed analysis of the amino acid residues involved in ligand binding to several iron–sulfur clusters. Therefore, it has become possible to examine which subunits contain individual iron–sulfur clusters, their location within the enzyme and what their ligand residues are. The discovery of g=2.00 EPR signals arising from two distinct species of semiquinone (SQ) in the activated bovine heart submitochondrial particles (SMP) is another line of recent progress. The intensity of semiquinone signals is sensitive to ΔμH+ and is diminished by specific inhibitors of Complex I. To date, semiquinones similar to those reported for the bovine heart mitochondrial Complex I have not yet been discovered in the bacterial systems. This mini-review describes three aspects of the recent progress in the study of the redox components of Complex I: (A) the location of the substrate (NADH) binding site, flavin, and most of the iron–sulfur clusters, which have been identified in the hydrophilic electron entry domain of Complex I; (B) experimental evidence indicating that the cluster N2 is located in the amphipathic domain of Complex I, connecting the promontory and membrane parts. Very recent data is also presented suggesting that the cluster N2 may have a unique ligand structure with an atypical cluster-ligation sequence motif located in the NuoB (NQO6/PSST) subunit rather than in the long advocated NuoI (NQO9/TYKY) subunit. The latter subunit contains the most primordial sequence motif for two tetranuclear clusters; (C) the discovery of spin–spin interactions between cluster N2 and two distinct Complex I-associated species of semiquinone. Based on the splitting of the g signal of the cluster N2 and concomitant strong enhancement of the semiquinone spin relaxation, one semiquinone species was localized 8–11 Å from the cluster N2 within the inner membrane on the matrix side (N-side). Spin relaxation of the other semiquinone species is much less enhanced, and thus it was proposed to have a longer distance from the cluster N2, perhaps located closer to the other side (P-side) surface of the membrane. A brief introduction of EPR technique was also described in Appendix Aof this mini-review
Ki-Energy (Life-Energy) Protects Isolated Rat Liver Mitochondria from Oxidative Injury
We investigated whether ‘Ki-energy’ (life-energy) has beneficial effects on mitochondria. The paradigm we developed was to keep isolated rat liver mitochondria in conditions in which they undergo heat deterioration (39°C for 10 min). After the heat treatment, the respiration of the mitochondria was measured using a Clarke-type oxygen electrode. Then, the respiratory control ratio (RC ratio; the ratio between State-3 and State-4 respiration, which is known to represent the integrity and intactness of isolated mitochondria) was calculated. Without the heat treatment, the RC ratio was >5 for NADH-linked respiration (with glutamate plus malate as substrates). The RC ratio decreased to 1.86–4.36 by the incubation at 39°C for 10 min. However, when Ki-energy was applied by a Japanese Ki-expert during the heat treatment, the ratio was improved to 2.24–5.23. We used five preparations from five different rats, and the significance of the differences of each experiment was either P < 0.05 or P < 0.01 (n = 3–5). We analyzed the degree of lipid peroxidation in the mitochondria by measuring the amount of TBARS (thiobarbituric acid reactive substances). The amount of TBARS in heat-treated, no Ki-exposed mitochondria was greater than that of the control (no heat-treated, no Ki-exposed). However, the amount was reduced in the heat-treated, Ki-exposed mitochondria (two experiments; both P < 0.05) suggesting that Ki-energy protected mitochondria from oxidative stress. Calcium ions may play an important role in the protection by Ki-energy. Data also suggest that the observed Ki-effect involves, at least, near-infrared radiation (0.8–2.7 μm) from the human body
Five Decades of Research on Mitochondrial NADH-quinone Oxidoreductase (complex I)
NADH-quinone oxidoreductase (complex I) is the largest and most complicated enzyme complex of the mitochondrial respiratory chain. It is the entry site into the respiratory chain for most of the reducing equivalents generated during metabolism, coupling electron transfer from NADH to quinone to proton translocation, which in turn drives ATP synthesis. Dysfunction of complex I is associated with neurodegenerative diseases such as Parkinson’s and Alzheimer’s, and it is proposed to be involved in aging. Complex I has one non-covalently bound FMN, eight to 10 iron-sulfur clusters, and protein-associated quinone molecules as electron transport components. Electron paramagnetic resonance (EPR) has previously been the most informative technique, especially in membrane in situ analysis. The structure of complex 1 has now been resolved from a number of species, but the mechanisms by which electron transfer is coupled to transmembrane proton pumping remains unresolved. Ubiquinone-10, the terminal electron acceptor of complex I, is detectable by EPR in its one electron reduced, semiquinone (SQ) state. In the aerobic steady state of respiration the semi-ubiquinone anion has been observed and studied in detail. Two distinct protein-associated fast and slow relaxing, SQ signals have been resolved which were designated SQNf and SQNs. This review covers a five decade personal journey through the field leading to a focus on the unresolved questions of the role of the SQ radicals and their possible part in proton pumping
Growth Inhibition of Cultured Human Liver Carcinoma Cells by Ki-energy (Life-energy): Scientific Evidence for Ki-effects on Cancer Cells
‘Ki-energy’ (life-energy) is believed to increase the immune activity of its practitioners. It has also been shown to cause neuropsychological effects. We undertook this study to obtain objective and scientific evidence as to whether or not a ‘Ki-effect’ could inhibit the growth of cultured cancer cells. Cultured human liver carcinoma cells, HepG2, were used. A Japanese Ki-expert held his fingers toward the cells in culture dishes for 5 or 10 min. After culturing for 24 h, we measured cell numbers, protein concentration per cell, certain mRNA expressions and the synthesis of regucalcin. The results were compared with those for control cells (non-treated cells). We found that the number of cells in the Ki-exposed groups were less than those in the controls by 30.3 and 40.6% with 5 and 10 min Ki-exposure, respectively. The protein content per cell in the Ki-exposed groups (5 and 10 min) was higher than that in the control groups by 38.8 and 62.9%, respectively. These results were statistically significant. Using RT–PCR, we found that the mRNA expression for c-myc, a tumor stimulator gene, was decreased, while that for regucalcin, which suppresses DNA synthesis, was increased. Our molecular biological studies and mathematical model analysis demonstrated that Ki-energy inhibited cancer cell division. The data also indicate that the Ki-effects involve some form of infrared radiation from the human body. This study suggests the possibility that Ki-energy may be beneficial for cancer patients because it suppresses cancer cell growth, and at the same time, it stimulates immune functions of the patients
Ki-energy (Life-energy) Stimulates Osteoblastic Cells and Inhibits the Formation of Osteoclast-like Cells in Bone Cell Culture Models
Some practitioners of the Nishino Breathing Method (NBM) were found to have a higher bone density than the average values of age- and gender-matched non-practitioners. Using bone cell culture models, we investigated a possible mechanism behind this observation. For the study of bone mineralization, we performed the following two experiments using cultured osteoblastic MC3T3-E1 cells: (i) Kozo Nishino, a Japanese Ki expert, sent Ki-energy to the cells once for 5 or 10 min after they were seeded in culture dishes in the presence of 10% fetal bovine serum (FBS). They were incubated for 72 h and the cells were counted. The number in the dish with 10-min Ki-exposure was significantly greater than that in the control (P < 0.01 with n = 8). We performed a reverse transcription-polymerase chain reaction (RT–PCR) study using these cells, but the mRNA expressions did not change significantly. (ii) After cells were incubated for 72 h without Ki-exposure (in the presence of FBS), they were further cultured for 48 h (in the absence of FBS) to promote differentiation. At the beginning of the second culture stage, Ki was applied once for 10 min. After 48 h, RT–PCR was performed. The mRNA expressions which are related to bone mineralization, such as Runx2, α1(I) collagen, alkaline phosphatase and osteocalcin, increased significantly (P < 0.05 and n = 4 for all). For the bone resorption study, we used mouse marrow cultures, which can form osteoclast-like cells in the presence of (1–34) parathyroid hormone (PTH), and stimulate resorption. We exposed these cells to Ki-energy twice for the duration of 5 or 10 min on day 0 and day 4. On day 7, the cells were counted. The number of osteoclast-like cells in dishes with Ki exposure was significantly smaller than those in control dishes (P < 0.05 with n = 5). The difference between 5-min exposure and 10-min exposure was not statistically significant. All of our data suggest that the Ki-effect on osteoporosis should be further explored
Philosophy, Psychology, Physics and Practice of Ki
Ki (in Japanese) or Qi (in Chinese) is the key concept in Eastern medicine, Eastern philosophy, as well as in martial arts. We explain the philosophical and psychological background of Ki. We emphasize that the unique aspects of Eastern philosophy are ‘non-linearity’ and ‘holistic’ approach. We then present physics aspect of Ki. Our experiments demonstrated that a ‘Ki-beam’ carries ‘entropy’ (or information), which is different from ‘energy’. We introduce our experience of having taught Ki to 37 beginners in the United States through the Nishino Breathing Method. If beginners had martial arts training or a strong background in music or dance, about half of them could sense Ki within 10 weeks (1 h class per week) of practice
Comparative Evaluation of Direct Thrombin and Factor Xa Inhibitors with Antiplatelet Agents under Flow and Static Conditions: An In Vitro Flow Chamber Model
Dabigatran and rivaroxaban are novel oral anticoagulants that specifically inhibit thrombin and factor Xa, respectively. The aim of this study is to elucidate antithrombotic properties of these anticoagulant agents under arterial and venous shear conditions. Whole blood samples treated with dabigatran or rivaroxaban at 250, 500, and 1000 nM, with/without aspirin and AR-C66096, a P2Y12 antagonist, were perfused over a microchip coated with collagen and tissue thromboplastin at shear rates of 240 and 600 s−1. Fibrin-rich platelet thrombus formation was quantified by monitoring flow pressure changes. Dabigatran at higher concentrations (500 and 1000 nM) potently inhibited thrombus formation at both shear rates, whereas 1000 nM of rivaroxaban delayed, but did not completely inhibit, thrombus formation. Dual antiplatelet agents weakly suppressed thrombus formation at both shear rates, but intensified the anticoagulant effects of dabigatran and rivaroxaban. The anticoagulant effects of dabigatran and rivaroxaban were also evaluated under static conditions using thrombin generation (TG) assay. In platelet-poor plasma, dabigatran at 250 and 500 nM efficiently prolonged the lag time (LT) and moderately reduce peak height (PH) of TG, whereas rivaroxaban at 250 nM efficiently prolonged LT and reduced PH of TG. In platelet-rich plasma, however, both anticoagulants efficiently delayed LT and reduced PH of TG. Our results suggest that dabigatran and rivaroxaban may exert distinct antithrombotic effects under flow conditions, particularly in combination with dual antiplatelet therapy
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