Respiratory Enzyme Activities Research Articles

Riemerella anatipestifer gen. nov., comb. nov., the Causative Agent of Septicemia Anserum Exsudativa, and Its Phylogenetic Affiliation within the Flavobacterium-Cytophaga rRNA Homology Group

The phylogenetic position of the causative agent of septicemia anserum exsudativa, now most often referred to as [Moraxella] anatipestifer (brackets indicate a generically misnamed taxon) or "[Pasteurella] anatipestifer," was established by performing rRNA cistron similarity studies. [Moraxella] anatipestifer belongs to rRNA superfamily V, together with the genera Flavobacterium, Cytophaga, Flexibacter, Weeksella, Capnocytophaga, and Sphingobacterium. The detailed structure of rRNA superfamily V, which now contains five major rRNA homology groups, is described. An analysis of various phenotypic parameters, including new data (cellular proteins and fatty acids) and previously published data (respiratory quinones, enzyme activities, and classical phenotypic features), revealed that [Moraxella] anatipestifer differs in many aspects from its closest relatives, Flavobacterium indologenes, Flavobacterium gleum, Flavobacterium indoltheticum, Flavobacterium balustinum, Flavobacterium meningosepticum, and Weeksella zoohelcum. The combined genotypic and phenotypic data indicate that this organism should be placed in a separate genus; the name Riemerella anatipestifer gen. nov., comb. nov. is proposed for this bacterium. The specific epithet anatipestifer is kept in order to avoid nomenclatural confusion. However, it should be emphasized that the illness caused by this organism is a septicemic disease which is not restricted to ducks.

Daunomycin-induced cardiomyopathy in rats and its possible therapy with peptide preparation isolated from the heart

A well-known consequence of treating malignant diseases with anthracycline antibiotics (AA), and the first to be noted by clinicians, is their cardiotropy, result ing in cardiomyopathy, in some cases with progressive heart failure and even a lethal ou tcome. Due to the high affinity of AA to membranes and their ability to intercalate between D N A bases, the immedia te and delayed effects of anthracycline therapy are manifested in inhibition of nucleic acid and protein synthesis, reduced activity of the mitochondrial respiratory enzymes, and disturbances of ion homeostasis . This results in an energy deficit, an overload with metabol ica l ly inactive calcium, and LPO activation in the cells, as well as impaired contractile funct ion, and enhanced diastolic rigidity of the myoca rd ium [5,7]. Bearing in mind that there are no effective means for protect ing the myoca rd ium under condi t ions of anthracycline cardiomyopathy, we proposed a peptide preparat ion f rom the heart (HP) which is known to s t imula te c a r d i o m y o c y t e repai r af ter damage caused by industrial toxins [2] and to possess an antiischemic effect [6]. In the present study we tested the possibility of correcting daunomycin-induced cardiomyopathy with the heart-derived peptide preparation.

Effect of propyl gallate feeding on antioxygenic and respiratory enzymes in liver of mice

Antioxygenic enzymes provide defense to the cell against free radicals produced during respiration. This study deals with the effect of propyl gallate feeding on antioxygenic and respiratory enzymes in liver of male mice of different age groups. Antioxidant increased the activities of catalase, glutathione reductase, ATPase and NADH-dehydrogenase significantly in 8-month-old mice, whereas the increase in activity in early and late growth stages was observed only at selective concentrations. The increased activities of antioxygenic enzymes on propyl gallate feeding may be attributed to an increase in the activities of respiratory enzymes.

Deletion of mitochondrial DNA in a case of early-onset diabetes mellitus, optic atrophy, and deafness (Wolfram syndrome, MIM 222300).

The Wolfram syndrome (MIM 222300) is a disease of unknown origin consisting of diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. Here we report on a generalized deficiency of the mitochondrial respiratory enzyme activities in skeletal muscle and lymphocyte homogenate of a girl suffering from the Wolfram syndrome. In addition, we provide evidence for a 7.6-kilobase pair heteroplasmic deletion (spanning nucleotides 6465-14135) of the mitochondrial DNA in the two tissues and show that directly repeated sequences (11 bp) were present in the wild-type mitochondrial genome at the boundaries of the deletion. Neither of the patient's parents was found to bear rearranged molecules. This study supports the view that a respiratory chain defect can present with insulin-dependent diabetes mellitus as the onset symptom. It also suggests that a defect of oxidative phosphorylation should be considered when investigating other cases of Wolfram syndrome, especially because this syndrome fulfills the criteria for a genetic defect of the mitochondrial energy supply: (a) an unexplained association of symptoms (b) with early onset and rapidly progressive course, (c) involving seemingly unrelated organs and tissues.

Changes in pigment levels, Rubisco and respiratory enzyme activity of Ficus benjamina during acclimation to low irradiance

The objective of the present study was to determine the influence of reduced irradiance on the activities of ribulose bisphosphate carboxylase‐oxygenase (Rubisco) and respiratory enzymes. Rooted cuttings of the tropical epiphyte. Ficus benjamina L., were grown in a shaded environment that excluded approximately 50% of the natural photosynthetically active irradiance (890 μmol m−2 s−1) for 4 months. Established plants were transferred and grown for 10 months under a range of irradiance levels with daily average maxima varying from a full‐sun environment to 20% full sun (100%−1735; 50%−890; 40%−695; and 20%−303 μmol m−2s−1). Chlorophyll, carotenoid and soluble protein content increased in Ficus leaves as irradiance level decreased, while Rubisco increased on a fresh weight basis but decreased on a protein basis. Glycolytic enzymes, enolase and pyruvate kinase, showed higher activities in full‐sun plants on a protein and fresh weight basis. However, the activity of two mitochondrial enzymes, aconitase and malate dehydrogenase, was not different under the various irradiance levels. When transferred to a very low irradiance environment (18 μmol m−2 s−1), mature leaves exhibited increased chlorophyll and carotenoid levels regardless of previous irradiance treatment. Exposure to very low irradiance resulted in a large increase in enolase and pyruvate kinase activities. Only plants grown under full sun conditions showed a decline in Rubisco activity following growth at very low irradiance. Together, these studies demonstrate the ability of mature leaves of Ficus to biochemically adjust photosynthetic and respiratory components over a wide range of irradiance.

Changes in pigment levels, Rubisco and respiratory enzyme activity of Ficus benjamina during acclimation to low irradiance

Changes in pigment levels, Rubisco and respiratory enzyme activity of Ficus benjamina during acclimation to low irradiance

Oxidative phosphorylation function and respiratory enzyme activities in myocardial mitochondria from autopsy cases of kfshan disease

Oxidative phosphorylation function and respiratory enzyme activities in myocardial mitochondria from autopsy cases of kfshan disease

Changes in major phospholipids of mitochondria during postischemic reperfusion in rat brain.

Major mitochondrial phospholipids were examined in rat brain after 30 minutes of reperfusion following 30- or 60-minute periods of ischemia to examine their changes and explore their relationship to mitochondrial dysfunction during postischemic reperfusion. The amount of phospholipids and the percentage of polyunsaturated fatty acid chains, which tended to decrease during 30 minutes of ischemia, recovered after reperfusion. However, after ischemia lasting for 60 minutes, these parameters did not recover but decreased further, suggesting progressive disruption of phospholipids by phospholipase A2 after reperfusion. These changes were particularly notable in cardiolipin, which is contained specifically in mitochondria. The changes were also closely associated with mitochondrial respiration and respiratory enzyme (cytochrome c oxidase and F0F1-adenosine triphosphatase) activities, which have been known to correlate with the amount of cardiolipin. These results suggest that phospholipid metabolism in mitochondrial membranes is an important factor bearing on the integrity of energy metabolism during postischemic reperfusion.

Is Parkinson's disease a mitochondrial disorder?

Parkinson's disease (PD) is a common degenerative disease, but its etiology is still unknown. However, since the discovery of MPTP, many investigators have been interested in the mitochondrial function in PD. We investigated mitochondrial functions in PD patients using the methods which have successfully been applied to mitochondrial myopathies (MM), i.e. assay of lactate and pyruvate, measurement of muscle mitochondrial respiratory enzyme activities and Southern blot analysis of muscle mitochondrial DNA. Parkinson's disease patients did not differ from controls in the mean blood and CSF (cerebrospinal fluid) lactate and pyruvate levels at the basal resting state or during an aerobic exercise. But mitochondrial complex I activity of the skeletal muscle was significantly decreased in PD. In the Southern blot analysis, we could not find major deletions or insertions of mitochondrial DNA in PD. Our studies disclosed a differential mitochondrial impairment between PD and MM. We discuss the implication of our observation.

Functional and molecular analysis of mitochondria in thyroid oncocytoma

SummaryWe report a functional and molecular analysis of nine oncocytic tumors of the human thyroid. In all the abundance of mitochondria observed ultrastructurally was accompanied by an increase in enzymatic activities of respiratory complexes I (NADH dehydrogenase), II (succinate dehydrogenase) IV (cytochrome c oxidase), and V (ATPase). Western blot analysis failed to detect uncoupling protein in the tumors. The elevated respiratory enzyme activities were paralleled by an increase in the mitochondrial DNA content. Restriction analysis of mitochondrial DNA gave no indication of heteroplasmy or other gross alterations. We conclude that the mitochondrial proliferation in oncocytic tumors is probably not the result of a compensatory mechanism for the deficiency in enzyme complexes of the mitochondrial respiratory chain.

Concomitant loss of respiratory chain NADH: ubiquinone reductase (complex I) and citric acid accumulation in Aspergillus niger

Growth, citric acid production and enzymatic activity of the mitochondrial respiratory enzymes of a wild-type and a citric-acid-producing mutant of Aspergillus niger have been compared during fermentation under citric-acid-accumulating and non-accumulating conditions. Under non-accumulating conditions, both strains showed standard growth and no citric acid production. The mutant strain was characterized by delayed onset of growth and lowered cell yield. Under citric-acid-accumulating conditions the wild-type strain exhibited decelerated growth and a maximal citric acid concentration of 12 g l−1. Reduced, but continuing growth and citric acid production of 32 g l−1 was observed for the mutant strain. In general, the mutant strain exhibited reduced activity for the proton-pumping respiratory complexes and enhanced activity for the alternative respiratory enzymes. In contrast to the stable activity of complex I in the wild-type strain, this complex was selectively lost in the mutant strain at the onset of citric acid production, while the alternative NADH dehydrogenases were kept at enhanced and constant activity. A possible causal connection between the loss of complex I and citric acid accumulation is discussed.

Degradation of mitochondrial phospholipids during experimental cerebral ischemia in rats.

Changes in content of brain mitochondrial phospholipids were examined in rats after 30 and 60 min of decapitation ischemia compared with controls, to explore the degradation of the mitochondrial membrane and its relation to dysfunction of mitochondria. Activities of respiratory functions and respiratory enzymes (cytochrome c oxidase; F0F1-ATPase) decreased significantly during ischemia. Considerable decreases in cardiolipin and phosphatidylinositol content were observed after 60 min, and other phospholipids showed similar but nonsignificant decreases in content. The amount of polyunsaturated fatty acids chains, such as arachidonic and docosahexaenoic acids, was reduced in each phospholipid, in some cases significantly, after 30 and 60 min of ischemia in time-dependent manners. Degradation of mitochondrial phospholipids during ischemia associated with the deterioration of mitochondrial respiratory functions suggested the significance of such changes in phospholipid content in disintegration of cellular energy metabolism during cerebral ischemia.

Structural and functional changes in organelles of liver cells in rats exposed to magnetic fields

Exposure of rats to magnetic fields of 10(-3) and 10(-2) T for 1 hr daily generated structural changes in hepatocytes mitochondria, endoplasmic reticulum, and ribosomes. Simultaneously there was an increase in the activities of the mitochrondrial respiratory enzymes: NADH dehydrogenase, succinic dehydrogenase, and cytochrome oxidase. The extent of the changes in liver cell properties following exposure depend on the duration of exposure to and the strength of the applied magnetic fields. Ultrastructural studies did not reveal any changes in external membranes of hepatocytes or in the membranes of cell nuclei. An increase in the amount of glycogen in hepatocytes of rats exposed to both 10(-3) and 10(-2) T was noted. The high level of cortisol in serum of exposed rats suggests that magnetic field may be a stress generating factor.

Effects of Nitrogen Nutrition on Nitrogen Partitioning between Chloroplasts and Mitochondria in Pea and Wheat

Nitrogen partitioning among proteins in chloroplasts and mitochondria was examined in pea (Pisum sativum L.) and wheat (Triticum aestivum L.) grown hydroponically with different nitrogen concentrations. In pea leaves, chloroplast nitrogen accounted for 75 to 80% of total leaf nitrogen. We routinely found that 8% of total ribulose-1,5-bisphosphate carboxylase/oxygenase adhered to thylakoids during preparation and could be removed with Triton X-100. With this precaution, the ratio of stroma nitrogen increased from 53 to 61% of total leaf nitrogen in response to the nitrogen supply, but thylakoid nitrogen remained almost constant around 20% of total. The changes in the activities of the stromal enzymes and electron transport in response to the nitrogen supply reflected the nitrogen partitioning into stroma and thylakoids. On the other hand, nitrogen partitioning into mitochondria was appreciably smaller than that in chloroplasts, and the ratio of nitrogen allocated to mitochondria decreased with increasing leaf-nitrogen content, ranging from 7 to 4% of total leaf nitrogen. The ratio of mitochondrial respiratory enzyme activities to leaf-nitrogen content also decreased with increasing leaf-nitrogen content. These differences in nitrogen partitioning between chloroplasts and mitochondria were reflected in differences in the rates of photosynthesis and dark respiration in wheat leaves measured with an open gas-exchange system. The response of photosynthesis to nitrogen supply was much greater than that of dark respiration, and the CO(2) compensation point decreased with increasing leaf-nitrogen content.

Oxidative metabolic response of peripheral blood monocytes of monkeys during primary and chronic Plasmodium knowlesi infection

The oxygen free radical generation (as determined by cytochrome c reduction) and respiratory burst enzyme activities were measured in the peripheral blood monocytes before infecting normal animals, during primary Plasmodium knowlesi infection, after treatment of primary infection with chloroquine, after administration of various subcurative doses following reinfection and after establishment of chronicity. For all the parameters of the oxidative response, no significant difference was observed during primary infection and after curing of primary infection. However, the response was significantly increased in the reinfected monkeys given subcurative therapy; this was followed by a sharp decline after the 4th subcurative dose, after which the response continued to be low until the attainment of chronicity. The results of the present study exclude the possibility of the increase in oxidative metabolism being the effect of the drug (i.e. chloroquine), since no significant difference was observed during primary infection and after its cure. The sustained low grade parasitaemia in the chronic stage, in spite of the sharp decrease in the oxidative response, suggests that some nonoxidant parasitic killing mechanism might be playing a role in the regulation of parasitaemia.

Respiratory enzymes in muscle: Interaction between environmental temperature, nutrition and growth

1. 1.In young pigs living at 35 or 10°C on a high or low energy intake, respiratory enzyme activities in longissimus dorsi muscle were greater both in the cold and on low intake. The elevated activities in the cold were unlikely to be related entirely to shivering since they were also found in muscle from the diaphragm. 2. 2.In a second study, pigs were kept close to thermal neutrality (26°C) on different levels of food intake and for different periods of time. For all animals, as body weight increased there was a decline in respiratory enzyme activity and the number of dark fibres in skeletal muscle. For those of the same weight, but different age and food intake, there was no difference in enzyme activity or number of dark fibres per unit area. 3. 3.At least part of the difference in respiratory enzyme activities related to energy intake must therefore be due to differences in body size. However, size is not the sole determinant of enzyme activity in skeletal muscle, since in animals of similar size those living at 10°C have greater enzyme activities than those at 35°C.

Respiratory Enzyme Activity in Low Temperature Sweetening of Susceptible and Resistant Potatoes

ABSTRACTDuring storage at 4°C and 12°C, a potato cultivar susceptible to chill‐sweetening (Norchip) accumulated significantly (P≤0.05) higher levels of sucrose, fructose and glucose than a potato selection resistant to chill‐sweetening (ND 860‐2). ND 860‐2 tubers exhibited a significantly (P≤0.05) higher respiration rate throughout storage, reflected in higher activities of phosphofructokinase (PFK), glucose‐6‐phos‐phate dehydrogenase (G6PDH) and 6‐phosphogluconate dehydrogenase (6PGDH). Storage significantly (P≤0.05) reduced respiration rate for both cultivars. G6PDH showed no significant (P>0.05) difference in specific activity or Vmax between 4°C and 12°C for either cultivar. However, Km decreased at 4°C for both cultivars, possibly due to build up of substrate.

Hepatic mitochondrial function and lysosomal enzyme activity in ethanol-potentiated aflatoxin B 1 hepatotoxicity

The possible role of hepatic mitochondrial function and lysosomal enzyme activity in ethanol-enhanced aflatoxin B 1 (AFB 1) hepatotoxicity was studied in male rats. Hepatic ATP content was significantly decreased in rats treated with ethanol (4.0 g/kg body wt.) and AFB 1 (2.0 mg/kg body wt.) compared with rats treated with AFB 1 alone at 12–72 h after AFB 1 administration. The decrease in hepatic ATP content was due to the decrease in the activity of NADH-cytochrome c reductase whereas cytochrome oxidase activity did not differ in rats treated with ethanol and AFB 1 when compared to AFB 1 alone. Total and free activities of hepatic lysosomal enzymes (glucuronidase, arylsulfatase and acid phosphatase) were significantly increased in rats treated with ethanol and AFB 1 at 24–36 h after AFB 1 administration when compared to AFB 1 alone. The increase in hepatic lysosomal enzyme activities correlated well with the increase in the lipid peroxide level of lysosomes in rats treated with ethanol and AFB 1. These findings indicate that the decrease in hepatic mitochondrial respiratory enzyme activities and the increase in lipid peroxide level of lysosomes might lead to a decrease in hepatic ATP content, and that the increase in the activities of hepatic lysosomal enzymes, respectively, enhance the AFB 1 hepatotoxicity of ethanol.

Inhibition and inactivation of NADH-cytochrome c reductase activity of bovine heart submitochondrial particles by the iron(III)-adriamycin complex

The NADH-cytochrome c reductase activity of bovine heart submitochondrial particles was found to be slowly (half-time of 16 min) and progressively lost upon incubation with the Fe2(+)-adriamycin complex. In addition to this slow progressive inactivation seen on incubation, a reversible fast phase of inhibition was also seen. However, if EDTA was added to the incubation mixture within 15 s, the slow progressive loss in activity was largely preventable. Separate experiments indicated that EDTA removed about one-half of the iron from the Fe2(+)-adriamycin complex in about 40 s. These results indicated the requirement for iron for the inactivation process. Since the Vmax. for the fast phase of inhibition was decreased by the inhibitor, the inhibition pattern was similar to that seen for uncompetitive or mixed-type inhibition. The direct binding of both Fe3(+)-adriamycin and adriamycin to submitochondrial particles was also demonstrated, with the Fe3(+)-adriamycin complex binding 8 times more strongly than adriamycin. Thus binding of Fe3(+)-adriamycin to the enzyme or to the inner mitochondrial membrane with subsequent generation of oxy radicals in situ is a possible mechanism for the Fe3(+)-adriamycin-induced inactivation of respiratory enzyme activity.

Nuclear 3,5,3′-Triiodothyronine Receptors in Skeletal Muscle of Normal and Small-for-Gestational Age Newborn Piglets

The number of nuclear T3 receptors in the longissimus dorsi muscle has been determined in normal and runt (intrauterine growth-retarded) newborn piglets. Values of maximal binding capacity (Bmax), as calculated by Scatchard analysis, were 48.2 +/- 4.3 and 39.7 +/- 4.7 mol X 10(-14).mg DNA-1 (mean values +/- SEM) for controls and runts respectively (p less than 0.01; n = 13 pairs of littermates). The lower Bmax in the runts may help to explain their reduced metabolic rate and lower respiratory enzyme activities in skeletal muscle, compared with controls of normal birth weight.