Differential synthesis by cultured atrial and ventricular rat cardiac myocytes of myosin light chain isoforms.

Dissociated cells from neonatal rat atria and ventricles were cultured in monolayers for 3 days. Newly synthesized 35S-methionine labeled myosin light chain isoforms ALC-1, ALC-2 (atrial) and VLC-1, VLC-2 (ventricular) were identified on 2D gels, and their pattern of synthesis was compared to that of myocard fragments immediately after explanation. ALCs were synthesized in 5- to 10-fold excess over VLCs by atrial cultures, whereas the converse was true for ventricular cultures, with two exceptions: one third of the LC-1 synthesized by ventricular fragments was ALC-1, and dissociated atrial cells synthesized very little LC-2 of either isoform.

Serum parvalbumin, an indicator of muscle disease in murine dystrophy and myotonia.

The soluble Ca(++)-binding protein parvalbumin (PV) is highly concentrated in fast muscle fibers of the wild type mouse. Employing Sandwich ELISA, we have shown that PV is present in the serum of normal mice and that its level is indicative of the disease status of muscle. Elevated PV levels were found in mice with X-linked dystrophy (mdx) and reduced levels in myotonic (ADR) mice.

Reduction of myosin-light-chain phosphorylation and of parvalbumin content in myotonic mouse muscle and its reversal by tocainide.

In muscle of the myotonic mouse mutant, 'arrested development of righting response', ADR, a reduced level of fast-myosin-light-chain-2 (LC2f) phosphorylation was observed in addition to a lowered parvalbumin content. In fast muscles, average phosphorylation levels of LC2f (LC2-P/LC2 total) were 0.76 mol/mol for wild type and 0.

Possible plasmid involvement in turimycin production in Streptomyces hygroscopicus.

Streptomyces hygroscopicus JA 6599 is the producer of the macrolide antibiotic turimycin. Mapping analysis by conventional matings and protoplast fusion techniques were carried out. The sequence of auxotrophic markers determined by using the method of minimizing the frequency of quadruple crossover recombinants, could be shown to be in accordance with the related marker sequence of Streptomyces coelicolor after both conjugation and protoplast fusion.