Infleuce of dietary levels of vitamin E and selenium on tissue and blood parameters in pigs.
(1/17862)
Eighteen barrows approximately three weeks of age were used in a 3 X 3 factorial arrangement to investigate the effect of level of supplemental vitamin E and selenium on tissue and blood parameters. Tissue selenium concentrations increased in a quadratic manner with increased selenium intake with kidney tissue containing considerably greater concentrations than liver, heart or muscle. Supplementation of the diet caused a three-fold increase in serum selenium within the first week with a slight tendency to further increases in subsequent weeks. Serum vitamin E of unsupplemented pigs declined by fifty percent during the experiment, whereas supplemental vitamin E resulted in increased serum vitamin E. There was a considerable viration in percent peroxide hemolysis. Correlation of -0.63 between percent peroxide hemolysis and vitamin E intake and -0.85 between percent peroxide hemolysis and serum vitamin E were observed. (+info)
Pathological changes in chickens, ducks and turkeys fed high levels of rapeseed oil.
(2/17862)
Rations containing 25% of either regular rapeseed oil (36% erucic acid), Oro rapeseed oil (1.9% erucic acid), soybean oil or a mixture of lard and corn oil were fed to chickens, ducks and turkeys. The regular rapeseed oil ration caused growth depression, increased feed conversion and anemia in all species. All the ducks and some of the chickens fed the regular rapeseed oil ration died. These dead birds were affected with hydropericardium and ascites. No deaths in the turkeys could be attributed to the regular rapeseed oil ration but some turkeys fed this ration had degenerative foci characterized by infiltrations of histiocytic and giant cells in the myocardium. Severe fatty change in the heart, skeletal muscles, spleen and kidney was found at an early age in all birds fed the regular rapeseed oil ration. Less severe fatty change but no other lesions were found in birds fed the Oro rapeseed oil and soybean oil rations. (+info)
In vitro effects of 2,4-dichlorophenoxy acetic acid (2,4-D) on bovine cells.
(3/17862)
Bovine fetal muscle cells were exposed to culture media containing 2 mg and 20 mg per liter of 2,4-dichlorophenoxy acetic acid (2,4-D) for varying intervals to determine the in vitro response of mammalian cells to this compound. The concentrations of 2,4-D used were comparable to those used in spray programmes although the residues normally found in pasture are much lower since 2,4-D is rapidly degraded under field conditions. Untreated and treated cultures were analyzed for total cell count, mitotic index and the percentages of differentiating and degenerating cells. The response of cultures to treatment was similar irrespective of the concentrations of 2,4-D used although in higher concentrations there was an initial drop in mitotic index. Other changes noted in treated cultures included an increase in differentiating and degenerating cells compared to those in control. The mitotic cells in treated cultures exhibited unipolar and tripolar spindles and a variety of other abnormalities including malorientation of the mitotic apparatus in relation to the axis of the cell. Myoblasts in initial stages of myogenesis were noted to be in mitosis in treated cultures suggesting that 2,4-D may have a stimulatory effect on myoblasts which in normal myogenesis are in post mitotic stage. (+info)
Synthesis and kinetic evaluation of 4-deoxymaltopentaose and 4-deoxymaltohexaose as inhibitors of muscle and potato alpha-glucan phosphorylases.
(4/17862)
alpha-Glucan phosphorylases degrade linear or branched oligosaccharides via a glycosyl transfer reaction, occurring with retention of configuration, to generate alpha-glucose-1-phosphate (G1P). We report here the chemoenzymic synthesis of two incompetent oligosaccharide substrate analogues, 4-deoxymaltohexaose (4DG6) and 4-deoxymaltopentaose (4DG5), for use in probing this mechanism. A kinetic analysis of the interactions of 4DG5 and 4DG6 with both muscle and potato phosphorylases was completed to provide insight into the nature of the binding mode of oligosaccharide to phosphorylase. The 4-deoxy-oligosaccharides bind competitively with maltopentaose and non-competitively with respect to orthophosphate or G1P in each case, indicating binding in the oligosaccharide binding site. Further, 4DG5 and 4DG6 were found to bind to potato and muscle phosphorylases some 10-40-fold tighter than does maltopentaose. Similar increases in affinity as a consequence of 4-deoxygenation were observed previously for the binding of polymeric glycogen analogues to rabbit muscle phosphorylase [Withers (1990) Carbohydr. Res. 196, 61-73]. (+info)
Metallothionein-null mice absorb less Zn from an egg-white diet, but a similar amount from solutions, although with altered intertissue Zn distribution.
(5/17862)
The influence of metallothionein (MT) on Zn transfer into non-gut tissues was investigated in MT-null (MT-/-) and normal (MT+/+) mice 4 h after oral gavage of aqueous 65ZnSO4solution at doses of 154, 385, 770 and 1540 nmol Zn per mouse. Zn transfer was not significantly different between MT+/+ and MT-/- mice and was directly proportional to the oral dose (slope = 0.127, r = 0.991; 0. 146, r = 0.994, respectively). Blood 65Zn and plasma Zn concentrations increased progressively in MT-/- mice at doses >154 nmol Zn, reaching levels of 2.4% of oral dose and 60 micromol/L, respectively, at the 1540 nmol Zn dose. The corresponding values for MT+/+ mice were approximately half, 1.0% and 29 micromol/L. Intergenotypic differences were found in tissue distribution of 65Zn within the body; MT-/- mice had higher 65Zn levels in muscle, skin, heart and brain, whereas MT+/+ mice retained progressively more Zn in the liver, in conjunction with a linear increase in hepatic MT up to the highest Zn dose. MT induction in the small intestine reached its maximum at an oral dose of 385 nmol Zn and did not differ at higher doses. Absorption of a 770 nmol 65Zn dose from a solid egg-white diet was only one fourth (MT+/+) and one eighth (MT-/-) of the Zn absorption from the same dose of 65Zn in aqueous solution. MT+/+ mice had greater (P < 0.05) Zn absorption from the egg-white diet than did MT-/- mice, indicating that gut MT confers an absorptive advantage, but only when Zn is incorporated into solid food. (+info)
The effect of denervation and dystrophy on the adaptation of sarcomere number to the functional length of the muscle in young and adult mice.
(6/17862)
In young animals the elongation of the limb bones increases the functional lengths of the muscles. In adult animals the functional length of a muscle can be increased by immobilizing it in the lengthened position. In both cases the muscle adapts by adding on more sarcomeres in series. The role of the nerve supply in this adaptation has been investigated using denervated muscles and muscles from dystrophic animals where there is thought to be an abnormality of the nerve supply. Postnatal sarcomere addition in denervated muscles falls short of that of controls. Although this might mean that the nerve supply is necessary for normal addition of sarcomeres, it is just as likely that there is a change in gait resulting from denervation, which affects the sarcomere number. Sarcomere number in fully grown mice is not affected by denervation, nor is the ability of the muscle to adapt to immobilization in the lengthened position. This is true for fast-twitch as well as slow-twitch muscles. In dystrophic muscles postnatal sarcomere addition is normal, although the presence of a few short fibres in the muscle may mean that some muscle fibres cannot adapt to an increase in the functional length of the muscle accompanying bone growth. Adult dystrophic muscle is capable of adapting to immobilization in the lengthened position. However, although the total number of additional sarcomeres is the same as in normal immobilized muscle, they are added on at a slower rate. The experiments show that although denervated and dystrophic muscle fibres are in a state of atrophy they are still capable of adding on sarcomeres in series when the functional length of the muscle is increased. It would appear that the mechanism which enables the muscle to respond in this way to an increased functional length does not involve the nerve supply. This work was supported by a grant from the National Fund for Research into Crippling Diseases. (+info)
Gamma-Actinin, a new regulatory protein from rabbit skeletal muscle. I. Purification and characterization.
(7/17862)
A new regulatory protein which we have designated as gamma-actinin has been isolated from native thin filaments of rabbit skeletal muscle. Depolymerized native thin filaments were fractionated by salting out with ammonium sulfate, and the precipitates obtained at 40--60% ammonium sulfate saturation were further subjected to DEAE-Sephadex and Sephadex G-200 column chromatography. The purified gamma-actinin was shown to have a chain weight of 35,000 daltons and had a strong inhibitory action on the polymerization of G-actin. The results of amino acid analysis indicated a unique amino acid composition of gamma-actinin as compared with other structural proteins of muscle. Non-polar and neutral amino acid residues were abundant. One cysteine residue was contained per one molecule of gamma-actinin and played a critical role in the maintenance of the inhibitory activity. Pelleting of gamma-actinin with F-actin showed that gamma-actinin binds to F-action. (+info)
Connectin, an elastic protein from myofibrils.
(8/17862)
The elastic protein isolated from myofibrils of chicken skeletal muscle was compared with extracellular non-collagenous reticulin prepared from chicken liver and skeletal muscle. The amino acid compositions of these proteins were similar except that their contents of Phe, Leu, Cys/2, and Hyp were different. The impregnations of the elastic protein and reticulin with silver were also different. The reticulin was not at all elastic. It also differed from reticulin in solubility and antigenicity. It is proposed to call the intracellular elastic protein connectin. (+info)