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Biomedical subjects

F Parenti

Publications and source records attributed to F Parenti.

At least 37 records · Page 2Linked to original sources
PubMed1978

Teichomycins, new antibiotics from Actinoplanes teichomyceticus Nov. Sp. I. Description of the producer strain, fermentation studies and biological properties.

A soil isolate of Actinoplanes that produces the chemically unrelated new antibiotics teichomycins A1 and A2 has been proposed as a new species named Actinoplanes teichomyceticus nov. sp. (ATCC 31121). Studies of medium and fermentation conditions indicated that the highest antibiotic titers, ca 900 u/ml, are obtained in a medium containing 1% (w/v) glucose, 1% cotton seed meal, 1% malt extract, and 0.4% yeast extract. Both teichomycin A1 and teichomycin A2 are highly active against gram-positive bacteria. Teichomycin A1 shows some activity against gram-negative bacteria. Both antibiotics cured mice experimentally infected with sensitive bacteria and showed low acute toxicity. Of the two antibiotics teichomycin A2 is the more active.

Actinomycetales↗
PubMed1977

Gardimycin, a new antibiotic inhibiting peptidoglycan synthesis.

Gardimycin, a new antibiotic, at 100 mug/ml, specifically inhibited cell wall synthesis and induced accumulation of uridine 5'-diphosphate-N-acetylmur-amylpentapeptide in whole cells of Bacillus subtilis. The antibiotic was active in a particulate enzyme preparation from Bacillus stearothermophilus: 60 mug/ml caused 50%, and 200mug/ml caused 100%, inhibition of peptidoglycan synthesis. Suppression of peptidoglycan synthesis was accompanied by parallel accumulation of the lipid intermediate. This mechanism of action is discussed in comparison with those of other antibiotics that are known to inhibit bacterial cell wall biosynthesis.

Anti-Bacterial Agents↗
PubMed1977

Synthesis and biological activity of some 2-aminoimidazoles.

A review of the literature showed that 2-amino-imidazoles have not benn taken into consideration as antimicrobial agents. Our preliminary data indicating that 2-amino-4(5)-phenylimidazole possessed a moderate in vitro activity prompted us to prepare a limited series of 2-amino-4(5)-arylimidazoles and of some related derivatives. In vitro atimicrobial screening gave evidence of a broad spectrum activity for some of them. Several compounds have been tested also against S. mutans. In particular, 2-amino-4(5)-(4-biphenylyl)-imidazole hydrochloride showed substantial activity in this test, confirmed also against defferent representative strains of S. mutans. When submitted to a plaque inhibition test, it strongly inhibited the plaque forming ability of a S. mutans strain.

Anti-Bacterial Agents↗
PubMed1976

Gardimycin, a new antibiotic from Actinoplanes. I. Description of the producer strain and fermentation studies.

Two strains of Actinoplanes have been isolated that produce a new peptide antibiotic named gardimycin. A detailed taxonomical study of such strains indicates that they differ between themselves and from all the described species of Actinoplanes. For this reason they are considered to be new species; for which the names A. garbadinensis nov. sp. and A. liguriae nov. sp. are proposed. The type strain of A. garbadinensis is A/10889(=ATCC 31049), the type strain of A. liguriae is A/6353 (=ATCC 31048). Studies on the medium and fermentation conditions are reported.

Actinomycetales↗
PubMed1975

Lipiarmycin, a new antibiotic from Actinoplanes. I. Description of the producer strain and fermentation studies.

The producer strain of the new antibiotic, lipiarmycin, is described. The colony morphology, the presence of globose sporangia bearing motile spores, the absence of aerial mycelium and the presence of meso-DAP in cell wall, ascribe this strain to the genus Actinoplanes. The pigmentation and morphological characteristics together with the cultural and physiological features distinguish this strain from all the described Actinoplanes species. It is considered to be a new species for which the name Actinoplanes deccanensis nov. sp. is proposed. Lipiarmycin is produced in an organic complex medium containing NaCl. Production occurs at the end of trophophase and continues, though at decreasing rate, during isophase.

Actinomycetales↗
PubMed1975

Lipiarmycin, a new antibiotic from Actinoplanes. II. Isolation, chemical, biological and biochemical characterization.

Lipiarmycin, a metabolite of Actinoplanes deccanensis nov. sp. (PARENTI et al.), has been isolated in pure form. It has a molecular formula C52 CONGRUENT TO 54H74 CONGRUENT TO 76Cl2O19, (M.W. = 1,073 CONGRUENT TO 1,099). From its chemical and physico-chemical characteristics, lipiarmycin can be considered a new antibiotic. Lipiarmycin is highly active against Gram-positive bacteria, including strains resistant to the medically important antibiotics and protects mice experimentally infected with Streptococcus haemolyticus. Liparmycin inhibits growth of susceptible bacteria by interfering with RNA synthesis.

Animals↗
PubMed1975

Lipiarmycin, a new antibiotic from Actinoplanes III. Mechanism of action.

In vivo, at low concentrations (less than or equal to 1 mug/ml), the antibiotic lipiarmycin specifically inhibits RNA synthesis in Bacillus subtilis. At a much higher concentration (100 mug/ml), syntheses of other macromolecules such as DNA and protein also appear to be suppressed. In vitro, the antibiotic caused 50% inhibition of DNA-dependent RNA-polymerase from B. subtilis at a concentration of 0.6 mug/ml and of that E. coli at 5 approximately 8 mug/ml. The activity of Escherichia coli DNA-polymerase I is inhibited 50% at 55 approximately 65 mug/ml. Lipiarmycin prevent ribonucleoside triphosphate polymerization only if added prior to the association between RNA-polymerase and DNA, and does not affect the elongation rate of RNA chains at concentrations up to 100 mug/ml. At that concentration, however, the antibiotic immediately blocks the polymerization of deoxyribonucleotide triphosphates catalyzed by DNA-polymerase I.

Actinomycetales↗