Monoclonal antibodies to leucine enkephalin

Monoclonal antibodies to leucine enkephalin have been produced after fusion of mouse myeloma cells with spleen cells from hyper-immune mice. Hybrid clones 2D1 and SL1 were characterised using radioimmunoassay and an enzyme-linked immunosorbent assay. The antibody 2D1 was of low affinity and showed a maximum sensitivity of 0.1ng. The antibody binds equally well to the sulphated leucine enkephalin and to methionine enkephalin. It does not cross-react with dynorphin, methionine enkephalin-arg-phe or oxidised methionine enkephalin. The hybrid clone SL1 appears to be specific for leucine enkephalin. Preliminary immunocytochemical studies have shown that both antibodies bind specifically to leucine enkephalin in defined areas of the central nervous system.     

Unusual domains of human alphoid satellite DNA with contiguous non-satellite sequences: sequence analysis of a junction region.

The sequence organization of cloned segments of Human DNA carrying unusual domains of alphoid satellite was studied by restriction mapping, electron microscopy and base sequence analysis. In some cases restriction mapping revealed the absence of the typical 340 bp EcoR 1 dimer, although blot hybridizations showed the extensive presence of alphoid satellite. A variant monomeric construction was demonstrated by DNA sequencing. Furthermore, inverted repeats within these domains were detected by electron microscopy. In one case these were shown to be the result of interruptions in the satellite sequence by members of a family of repetitive, conserved elements.     

Growth of Pure and Mixed Cultures of Micro-organisms Concerned in the Treatment of Carbonization Waste Liquors

S ummary : Three strains of bacteria responsible for the destruction of the major constituents of carbonization waste liquor were isolated from a laboratory scale, activated sludge plant successfully treating such a liquor. Of the 3 strains one was able to grow on thiocyanate; the other 2 strains grew well on phenol. Behaviour of these organisms in pure and mixed culture showed marked differences: in pure culture, growth of the thiocyanate-degrading strain was unaffected by the presence of 100 mg of phenol/l, but in mixed culture, active growth of another organism on the phenol completely inhibited growth on the thiocyanate. Batch and continuous culture experiments were made with 2 organisms competing for phenol. Both stimulation and inhibition of growth were found, dependent on the ratio between the concentrations of organisms present.     

Characterization of the protein from gas-vacuole membranes of the blue-green alga,Microcystis aeruginosa

Summary The purified protein which constitutes the membranes of the gas vacuoles of the the blue-green alga, Microcystis aeruginosa, was partially characterized. Gel electrophoresis and end-group analysis indicate that the protein is a single species. Strongly protic solvents such as formic acid are the only reagents causing appreciable solubilization of the membrane protein. Infrared spectroscopy shows that the membrane protein has both -helix or random-coil conformation, and -conformation.This work was supported by the U. S. Atomic Energy Commission under Contract AT-(11-1)-1338.     

AMINO ACID DISTRIBUTION AND INCORPORATION INTO PROTEINS IN ISOLATED, ELECTRICALLY-STIMULATED CEREBRAL TISSUES

—The uptake of radioactive amino acid by incubated cerebral cortex slices is found to be a first order process. Incorporation of the radioactive amino acid into tissue protein is from a precursor pool that has first equilibrated with the intracellular endogenous free amino acids. Ways of calculating the amino acid incorporation in molar quantities from the observed incorporation of radioactivity are discussed, and it is concluded that the specific radioactivity of the intracellular acid-soluble fraction is the best basis for such estimates. The in vitro incorporation of leucine into tissue protein is estimated to be approximately 1±2 mμnol/mg protein/h, and of valine 0±4 mμmol/mg protein/h. Addition of free amino acids to the media had little or no effect on the calculated rates of incorporation. On incubation for 1 h the total free valine in tissue and medium increased by 0±43 μmol/g and leucine increased by 0±55 μmol/g. Estimates of amino acid incorporation based on the specific radioactivity of the media amino acids can give misleading results if this considerable release of amino acids into the medium is not taken into account. Electrical stimulation of neocortical slices with a variety of types of pulses was either without effect or decreased incorporation into portein. The decrease could not be directly correlated with changes in tissue K⁺ nor with the utilization of ATP. Mild, local stimulation of the lateral olfactory tract of piriform cortex slices was without effect on tissue phosphocreatine, K⁺ or amino acid incorporation.     

Protein-bound phosphorylserine in acid hydrolysates of brain tissue. The determination of [32P]phosphorylserine by ion-exchange chromatography and electrophoresis

1. Partial acid hydrolysates of proteins derived from cortical slices of guinea-pig brain were divided into two parts and fractionated by ion-exchange chromatography and high-voltage electrophoresis. 2. The apparent yield of protein-bound phosphorylserine by the ion-exchange method was about three times that obtained by electrophoresis. 3. The specific radioactivity of phosphorylserine isolated from (32)P-labelled slices by electrophoresis was twice that isolated by chromatography. 4. The discrepancies were found to be due to the presence of unlabelled phosphates of unknown composition in the ;phosphorylserine' fraction obtained by the ion-exchange method. 5. Electrical stimulation of slices respiring in the presence of [(32)P]phosphate increased the specific radioactivity of the total phosphate in the chromatographic ;phosphorylserine' fraction by 53+/-11%, as compared with only 19+/-5% for the phosphorylserine isolated by electrophoresis.