Mitochondria, isolated

Effects of Allelochemlcals on ATP Supply. Allelochemlcals might decrease the ATP content of tissue by either increasing ATP utilization or decreasing ATP production. Some allelochemlcals that inhibit mineral absorption decrease ATP content of plant tissues. Salicylic acid decreased the ATP content of oat roots in a pH dependent manner (Figure 3). This result suggested that mitochondrial production of ATP was decreased in the tissue. On the other hand, Tillberg (38) found that salicylic acid and cinnamic acid increased the ATP content of Scenedesmus. Various flavonoids inhibited ATP production by mitochondria Isolated from cucumber (Cucumls satlvus L.) hypocotyls (54). Flavones such as kaempferol were more inhibitory than the corresponding flavanones. Substituted cinnamic acids such as caffeic acid were not inhibitory. 

H2S consumption was exhibited by mitochondria isolated from the gills of the marine ribbed mussel Geukensia demissa, an inhabitant of sulfide-rich intertidal sediment, in an... 

Andre N, Braguer D, Brasseur G, et al. Paclitaxel induces release of cytochrome c from mitochondria isolated from human neuroblastoma cells. Cancer Res 2000 60(19) 5349-5353. 

In order to provide heat when it is required to maintain or increase body temperature, a mechanism must exist for the regulation of the activity of this uncoupling protein. The mechanism has been established by following the principles described in Chapter 3. The properties of the uncoupling protein are studied using mitochondria isolated from brown adipose tissue in vitro (as described in Appendix 9.9). 

The properties are as follows, (i) The activity of the protein (i.e. the inward transport of protons) is inhibited by ATP. (ii) The activity of the protein is increased by the presence of long-chain fatty acids, since they relieve the ATP inhibition, (iii) When mitochondria, isolated from brown adipose tissue, are incubated in the presence of fatty acids, there is a sharp increase in the rates of electron transfer, substrate utilisation and oxygen consumption, whereas the rate of ATP generation remains low. These studies indicate that the rate of proton transport, by the uncoupling protein, depends on the balance between the concentrations of ATP and fatty acids, (iv) In adipocytes isolated from brown adipose tissue, the rate of oxygen consumption (i.e. electron transfer) is increased in the presence of catecholamines. 

The underlying cause of mitochondrial dysfunction can be investigated in muscle using mitochondria isolated from a biopsy sample. They are incubated with different substrates and the oxygen consumption is measured. Defects in complexes 1, 111 or IV can be identihed in this way (Appendix 9.9). 

Intact tobacco plants were exposed to 0.60-0.70 yl/1 ozone for 1 hr mitochondria isolated from visibly injured tissue demonstrated an inhibition of oxidative phosphorylation in conjunction with an increase in respiration (6). However, when detached tobacco leaves were fumigated with 1.0 yl/1 ozone for 1-5 hr, the mitochondria extracted from the tissue prior to s3rmptom development exhibited reduced oxygen uptake and reduced oxidative phosphorylation (7 ). In an experiment of similar design when ozone was bubbled through a solution of isolated mitochondria, both respiration and oxidative phosphorylation were reduced (7 ). 

Introduction of HM mixture induced passive permeability of mitochondria membranes for K, and resulted in aggravation of proton permeability (Fig. 22.3). Statistically significant differences in swelling rate of mitochondria isolated from the rat liver between different animal groups, was observed in ammonium nitrate medium from the second minute tiU the end of the experiment. Similar dynamics... 

Hamada, M. Sumida, M. Okuda, H. Watanabe, T. Nojima, M. Kuby, S.A. Adenosine triphosphate-adenosine-5-monophosphate phosphotransferase from normal human liver mitochondria. Isolation, chemical properties, and immunochemical comparison with Duchenne dystrophic serum aberrant adenylate kinase. J. Biol. Chem., 257, 13120-13128 (1982)... 

Eugene Kennedy and Albert Lehninger showed in 1948 that, in eulcaiyotes, the entire set of reactions of the citric acid cycle takes place in mitochondria. Isolated mitochondria were found to contain not only all the enzymes and coenzymes required for the citric acid cycle, but also all the enzymes and proteins necessaiy for the last stage of respiration—electron transfer and ATP synthesis by oxidative phosphoiylation. As we shall see in later chapters, mitochondria also contain the enzymes for the oxidation of fatty acids and some amino acids to acetyl-CoA, and the oxidative degradation of other amino acids to a-ketoglutarate, succinyl-CoA, or oxaloacetate. Thus, in nonphotosynthetic eulcaiyotes, the mitochondrion is the site of most energy-yielding... 

The discovery that DNA forms catenanes and knots, some of them extremely complex, initiated a new field of research which has been called Biochemical Topology [21]. In 1967, Vinograd and co-workers detected in HeLa cell mitochondria isolable DNA molecules that consist of independent, double-stranded, closed circles that are topologically interlocked or catenated like the links in a chain [22, 23]. A few years later, catenanes had been observed everywhere that circular DNA molecules were known [24] and the first knot was found by Liu and coworkers in single-stranded circular phage fd DNA treated with Escherichia coli co-protein [25]. In 1980, knots could also be generated in double-stranded circular DNA [26]. 

Carter, C.E., Wells, J.R. and Madnnis, A.J. (1972) DNA from anaerobic Ascaris lumbricoides and ffymenolepis diminuta mitochondria isolated by zonal centrifugation. Biochimica et Biophysica Acta 262, 135-144. 

Ishikawa, M. and Yoshida, S., Seasonal changes in plasma membranes and mitochondria isolated from Jerusalem artichoke tubers. Possible relationship to cold hardiness, Plant Cell Physiol., 26,1331-1344, 1985. 

Hafner, R.P., C.D. Nobes, A.D. McGown, and M.D. Brand (1988). Altered relationship between proto-nmotive force and respiration rate in non-phos-phorylating liver mitochondria isolated from rats of different thyroid hormone status. Eur. J. Biochem. 178 511-518. 

The biopsy material is used to obtain biochemical, morphological, and genetic information to establish a diagnosis. Mitochondria isolated from the fresh muscle biopsy or from cells (fibroblasts) cultured from the skin biopsy can be used to measure respiratory chain activity by polarography. This procedure measures 02 consumption as different respiratory chain substrates are added to the mitochondrial suspension. 

The parenchymatous liver cells (hepatocytes) hold a key position in the overall metabolism of iron (57, 58, 59, 60), and since functionally intact liver mitochondria can be conveniently prepared at high yield, these mitochondria have been most extensively studied so far. The iron transporting system discussed above for liver mitochondria is present also in mitochondria from other tissues and animal species (Table III). Quantitatively, erythroid cells of the bone marrow play the most important role in the overall metabolism of iron (61), and it was therefore not unexpected to find that the energized uptake of iron by isolated reticulocyte mitochondria exceeds that of mitochondria isolated from, for example, liver, kidney, and heart (Table IV). Thus, a relationship appears to exist between the rate and extent of heme protein turnover in mitochondria isolated from different tissues and their energized iron accumulation (30). Thus, it is evident that cellular differentiation is expressed at the mitochondrial level by modulation of the activity of essential functions related to iron transport and heme biosynthesis. 

Table IV. Energy-Dependent Accumulation of Iron and Calcium by Mitochondria Isolated from Reticulocytes and Various Organs of Rabbit"...

Fig. 7.4 (a) Dose-response of the lamellarin M-induced mitochondrial depolarization in P388 cells, (b) Monitoring of the mitochondrial membrane potential (A rm) by realtime flow cytometry, using functional mitochondria isolated from P388 cells and the fluorescent probe JC-1. 

Sources of enzyme activity were purified bovine heart a-ketoglutarate dehydrogenase from Sigma, mitochondria isolated from brains and livers of adult Mongolian gerbils (2-4 mg protein/mL, stored at -80°C until use), and platelets isolated from heparinized blood that had been homogenized by sonication before use. 

Cytochrome P450scc was purified from mitochondria isolated from bovine adrenal cortex by a published protocol. 

The assay was suitable for measuring the activity in intact and detergent-disrupted mitochondria isolated from rat, rabbit, and pigeon tissues. 

In 1961, Vitols and Linnane (1 ) reported that mitochondria isolated from S. cerevisiae showed identical P/0 values for oxidation of succinate and NAD-linked substrates. These results were the first indication of the absence of coupling site 1 in S. cerevisiae. Mackler et al. (127) and... 

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