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F Cobianchi

Publications and source records attributed to F Cobianchi.

44 records · Page 3Linked to original sources
PubMed1978

Properties of the high-molecular-weight deoxyribonuclease of Bacillus subtilis degrading single-stranded DNA.

We have studied the properties of the high-Mr DNAse degrading single-stranded DNA which is present in extracts of Bacillus subtilis. This enzyme is a heterogeneous aggregate of identical subunits with an Mr of 36 000, as measured in dodecylsulfate/polyacrylamide electrophoresis. The aggregate can be disassembled by the presence of Triton X-100, but reforms spontaneously following removal of the detergent. A mild proteolytic treatment of the aggregate causes the irreversible and nearly quantitative conversion into the free subunit. The modified subunit has identical properties (in terms of size, chromatographic adsorption and catalytic activity) as the small DNAse previously described by Ciarrocchi et al. [Eur. J. Biochem. 61, 487 (1976)], i.e. an endonuclease highly specific for single-stranded DNA and producing 5'-P and 3'-OH ends.

Bacillus subtilis↗
PubMed1977

Modulation of deoxyribonucleic acid polymerase III level during the life cycle of Bacillus subtilis.

Deoxyribonucleic acid (DNA) polymerase III is not detectable in Bacillus subtilis spores; the enzyme activity appears 20 to 30 min after spore activation and rapidly increases just before the onset of the first round of DNA replication (30 min later); the level of polymerase III further increases and reaches its maximum (on a per-genome basis) when the cells enter the vegetative phase of growth; this level is six- to eightfold higher than the one observed during germination. In the stationary phase, the polymerase III drops to levels comparable to those found in germinating spores at the first round of replication. On the contrary, DNA polymerase I is present at appreciable levels in the dormant spore; it increases during vegetative growth by a factor of three and, during the stationary phase, reaches its maximum level which is sixfold higher than that observed in the spores. The block of protein synthesis during vegetative growth does not cause an appreciable reduction of the two enzymes (in absolute terms), showing that the regulation of their levels is probably not due to a balance between synthesis and breakdown. These results indicate that polymerase III is probably one of the factors controlling the initiation of DNA synthesis during spore germination.

Bacillus subtilis↗
PubMed1976

An intracellular endonuclease of Bacillus subtilis specific for single-stranded DNA.

We have fractionated from extracts of Bacillus subtilis the DNase activity specific for single-stranded DNA; the activity separates in two main fractions on Sephadex G-200, a larger one (Mr greater than 400 000) and a smaller one (Mr approximately 30 000). We have purified the smaller, more abundant fraction nearly 3000-fold. The purified enzyme has a pH optimum close to 8, is activated by Ca2+, and is inhibited by EDTA; the enzyme hydrolyses single-stranded DNA at a rate approximately 40 times greater than double-stranded DNA. The mode of action is endonucleolytic on both substrates, but the possiblility that the two activities may reside on different molecules is not ruled out. The products have 5'-P and 3'-OH ends. The enzyme is different from those purified from the culture media of the same organism in several respects; the latter are all extracellular enzymes, they are not specific for single-stranded DNA (except one) and have all an exonucleolytic mode of action.

Bacillus subtilis↗
PubMedDate not supplied

Antibodies to hn-RNP protein A1 in systemic lupus erythematosus: clinical association with Raynaud's phenomenon and esophageal dysmotility.

Antibodies to recombinant hn-RNP protein A1 were found by ELISA in sera from 26 out of 67 unselected patients with systemic lupus erythematosus. A higher number of anti-A1 positive patients had Raynaud's phenomenon (50% vs 7%) and esophageal dysmotility (42% vs 5%) than the anti-A1 negative patients. All 8 patients with both Raynaud's phenomenon and esophageal dysmotility had a positive anti-A1 assay. No association was found with other clinical findings, nor with disease activity and treatment regimes. Anti-A1 antibodies did not correlate with anti-RNP and anti-Sm antibodies, which were present in 30% and 12% of the anti-A1 positive cases and in 22% and 7% of the anti-A1 negative cases, respectively. Our results indicate that antibodies to hn-RNP protein A1 may be associated with a subset of SLE patients with clinical features overlapping those of progressive systemic sclerosis and quite distinct from the group identified by anti-RNP antibodies.

Adolescent↗
PubMedDate not supplied

Effect of fedotozine on human distal colon.

Fedotozine was rested in colonic strips removed during surgery from patients suffering from different diseases of the colon; the effects were compared to those of morphine and of the selective opiate agonist U-69593. Fedotozine did not affect the spontaneous motility of human colonic strips, unless very high concentrations were used. Fedotozine (10(-6)-3 x 10(-4) M) induced a concentration-dependent reduction of the excitatory effect induced by field stimulation, an effect which was partially mimicked by compound U-69593 and by morphine but not inhibited by naloxone. The cumulative dose-response curve to exogenous acetylcholine was inhibited by fedotozine (3 x 10(-4) M), whereas morphine had no effect up to 3 x 10(-4) M. In colonic strips incubated with [3H]-choline, fedotozine (10(-5)-10(-4) M) induced an erratic decrease of acetylcholine-release induced by electric stimulation. In our experimental model, the inhibitory effect of fedotozine does not seem to be related to opioid receptor activation.

Acetylcholine↗