Hexapod.

SAGE III (Stratospheric Aerosol and Gas Experiment), an Earth-observation instrument developed by NASA's Langley Research Center (LaRC), was one of the first scientific external payloads selected for the International Space Station. It was conceived to fly on a spacecraft able to provide +/- 1 degree pointing accuracy. Since the ISS's attitude can vary by several degrees over a long period, it was therefore necessary to provide a dedicated nadir-pointing system. For this task, NASA selected the hexapod-based pointing system ("Hexapod" for short) included by ESA in the list of proposed European contributions to the ISS early utilisation phase. Launch is currently scheduled with assembly flight UF-3, although this could be modified by revisions in the ISS assembly sequence.

Erythrocyte alkaline phosphatase in patients with myotonic muscle disorders.

The allosteric behaviour of the p-nitrophenyl-phosphatase (E.C.3.1.3.1.) from membrane erythrocytes was investigated in the following multisystemic diseases: myotonic dystrophy, limb-girdle muscular dystrophy, Charcot-Marie-Tooth and juvenile spinal muscular atrophy; in myotonia congenita, which is not a multisystemic disease, and in healthy controls. The Hill coefficient in F inhibition in controls was different from that in multisystemic diseases patients but not from that in myotonia congenita patients. Changes in the cooperative type kinetics would suggest that the interaction membrane-enzyme in controls and in patients with neuromuscular disorders is only different for multisystemic diseases.

Erythrocyte membrane-bound acetylcholinesterase in vitamin E deficient rabbits.

1. The specific activities of erythrocyte membrane-bound acetylcholinesterase (EC 3.1.1.7.) and soluble hexokinase (EC 2.7.1.1.) in vitamin E deficient and vitamin E sufficient rabbits were investigated. 2. Acetylcholinesterase specific activities values of 43.4 in deficient and 57.4 in sufficient vitamin E rabbits were obtained. Hexokinase specific activity was not modified, and values of 3.31 in deficient and 3.6 in controls were found. 3. No peroxidation process was detected by us on vitamin E deficient diets. 4. These observations would suggest that the membrane stabilizing effect of vitamin E may be accomplished by a mode of action not necessarily related to its ability to prevent lipid peroxidation.

Effect of chronic administration of verapamil in Duchenne muscular dystrophy.

1. In DMD patients the effect of chronic treatment with verapamil was investigated in the p-nitrophenylphosphatase from erythrocytes, the CK and LDH in serum and the functional activity of the muscle. 2. A different behaviour in the p-nitrophenylphosphatase from untreated compared to treated DMD patients and controls is supported by the following findings: (a) values of "n" altered in F- inhibition of the enzyme with Hill coefficients -1.43, -2.18 and -2.19; (b) Arrhenius plots between 16 and 40 degrees C with inflection points for the enzyme from treated DMD patients and controls and not from untreated DMD patients. 3. Although CK and LDH in serum and the muscular evaluation showed no statistical difference between both groups, evidence is presented that in treated DMD patients the interaction membrane-enzyme is different from untreated DMD patients.

Fish muscle cytoskeletal network: its spatial organization and its degradation by an endogenous serine proteinase.

The extraction of white croaker skeletal myofibrils with KI rendered a residue in which a network of longitudinal and transverse filaments could be observed by scanning electron microscopy. A trypsin-like serine proteinase isolated from the same muscle was able to produce a complete and rapid disruption of the network, while major myofibrillar proteins were only slightly modified. This fact suggests that the disassembly of the cytoskeletal network may be an early event in the proteolysis of myofibrils. Desmin was not attacked by the proteinase under the assayed conditions, which indicates that some other unidentified component of the network would be the primary target of the action of the enzyme on myofibrils.

Allosteric transition of erythrocyte alkaline phosphatase from Duchenne muscular dystrophy (DMD) patients and Duchenne muscular dystrophy carriers (Homo sapiens).

1. The kinetic properties of the p-nitrophenylphosphatase (EC 3.1.3.1) from erythrocytes was investigated in DMD-patients and DMD-carriers. 2. A different allosteric behaviour in the p-nitrophenylphosphatase from DMD-patients and DMD-carriers compared to controls is supported by the following findings: (a) values of n altered in F- inhibition of (K+)-activated p-nitrophenylphosphatase with Hill coefficients -1.5, -2.2 and -3.1; (b) heterotropic effect of increased concentration of Mg2+ on F- inhibition which is reverted by K+ in DMD-carriers and in control, but not in DMD-patients. 3. Evidence is presented showing that in DMD-patients and in DMD-carriers the interaction membrane-enzyme is different from the corresponding controls.

Activation of an alkaline proteinase from fish skeletal muscle by fatty acids and sodium dodecyl sulphate.

1. Fish skeletal muscle contains an alkaline thiol proteinase with a temperature optimum of 60 degrees C and undetectable activity below 50 degrees C. 2. The present study shows that fatty acids and sodium dodecyl sulphate (SDS) shifted the temperature-activity curve of the enzyme toward the lower temperature side. 3. All unsaturated fatty acids tested strongly stimulated proteolytic activity at 37 degrees C, whereas myristic acid was the only saturated fatty acid that produced an important degree of activation. 4. These effects could be observed at millimolar concentrations of the reagents.

4-Nitrophenylalkaline phosphatase inhibition in muscular dystrophy.

The allosteric behaviour of 4-nitrophenylphosphatase from membrane erythrocytes was investigated in Duchenne muscular dystrophy (DMD) patients, in female carriers and in healthy controls. Cooperative type kinetics with a Hill coefficient of -2.19, -1.71 and -1.54 has been obtained from the inhibition by fluoride in controls, female carriers and Duchenne patients, respectively. Our observation supports the previously described membrane abnormalities in DMD erythrocytes and may extend then to female carriers.

Action of a serine proteinase from fish skeletal muscle on myofibrils.

The action of a serine proteinase from fish skeletal muscle on myofibrils was studied. The enzyme was able to destroy the structural integrity of myofibrils, and to degrade both their major contractile and cytoskeletal constituent proteins. Proteolysis could be completely prevented by the addition of a trypsin inhibitor isolated from the same muscle.

Isolation and characterization of Pediococcus halophilus from salted anchovies (Engraulis anchoita).

The presence of bacteria in salted anchovies during and at the end of the curing process was investigated. Attempts to isolate bacteria under aerobic or anaerobic conditions led to the isolation of only bacteria of the genus Pediococcus which were identified as Pediococcus halophilus. The isolates correspond to a rather heterogeneous group in which some of the members differ in some biochemical tests from the types described in the literature.