We have isolated and characterized a cDNA of 1183 bp, pL6-411, from rat L6 muscle cells. This cDNA contains repetitive sequences - including two inverted copies of the previously described identifier sequence - as shown by sequence analysis. Repetitive sequences from pL6-411 characterize a family of RNAs which is specifically induced during L6 myotube formation. Another part of the pL6-411 sequence, existing at low-copy number per haploid rat genome, hybridized to two RNAs of 5 kb and 2 kb from L6 myoblasts as well as from L6 myotubes. A third pL6-411-related RNA of 150 bases was detected which hybridized with the repetitive sequence but did not hybridize with the low-copy number part of pL6-411. It appears that the 'identifier' sequence in this population of small RNAs is complementary to one of the 'identifier' copies in the pL6-411-related RNA. Finally, we identified on cDNA pL6-411 the recognition site for the TGGCA-binding protein and in both orientations a total of four putative promoters for RNA polymerase III.

Animals↗

PubMed1982

Isolation and partial characterization of the most immunologically reactive antigen from Mycobacterium tuberculosis H37Ra culture filtrate.

The culture filtrate of Mycobacterium tuberculosis H37Ra was fractionated by ammonium sulphate precipitation, diethyl aminoethyl (DEAE) cellulose-Sephadex A-50 column chromatography, preparative isoelectric focusing and polyacrylamide gel electrophoresis to isolate the most antigenic tuberculoprotein. One protein, designated P2, was isolated and determined by immunodiffusion to be the most immunologically reactive antigen present in H37Ra culture filtrate. This protein had a molecular weight of about 22 000, a sedimentation constant of 2.2S and was present in Seibert's A, B, and C proteins.

Antigens, Bacterial↗

PubMed1981

Thermodynamic and kinetic studies of the interaction between T5-phages and their receptor, isolated from Escherichia coli b, in the absence and presence of Triton X-100.

Particles with receptor activity for T5-phages were isolated from the outer membrane of Escherichia coli B. We describe the interaction of these particles with T5-phages as a two-step chemical reaction. The rate constants were estimated from the inactivation kinetics. The transition-state theory permits the calculation of the entropy, enthalpy, and Gibbs free energy of activation. In the absence of Triton X-100, the reaction can be described with one set of thermodynamic constants for the temperature range from 10 degrees to 40 degrees C. The addition of Triton, which results in the splitting of receptor particles and in the building of mixed micelles, causes a complicated dependence on temperature. In this case, a subdividing of the temperature range measured into two parts yields two sets of thermodynamic constants that permit a good description of experimental kinetics.

Detergents↗