CC-1065 (NSC-298223), a new antitumor antibiotic. Production, in vitro biological activity, microbiological assays and taxonomy of the producing microorganism. (1/123)

A new antitumor antibiotic is produced in fermentation liquors of Streptomyces zelensis sp.n. The antibiotic is biologically active at extremely low concentrations. At 40 pg/ml, it inhibited 90% of the growth of L1210 cells in culture in tube dilution assays. The minimal inhibitory concentrations against Gram-positive bacteria is between 1 approximately 10 ng/ml, while these values for Gram-negative bacteria and fungi are mostly under 1 microgram/ml. A microbiological assay with Bacillus subtilis can detect concentrations of 1 approximately 2 ng/ml.  (+info)

Antibiotics and the Aberdeen typhoid outbreak in 1964. (2/123)

This paper gives an abbreviated account of part of a research programme which followed the Aberdeen typhoid outbreak in 1964. Chloramphenicol, the main antibiotic used in treatment, was shown to have a minimum inhibitory concentration (MIC) of between 5 and 2-5 mug./ml. for the S. typhi phage type 34 of the outbreak. The MIC for methacycline was between 5 and 2-5 and 2 mug./ml. Whereas the deep and shallow broth techniques used gave similar results with these antibiotics, the MIC for ampicillin, and also cephaloridine, was less in the deep than in the shallow broths. Serum assays in patients given ampicillin or cephaloridine yielded abnormally high concentrations of both antiboitics when S. typhi phage type 34 was the test organism whereas, with other test organisms, the concentrations were within expectation. These abnormally high values fell within expected values when the sera under investigation had first been heated to 56 degrees C. for 30 min. before assay against the S. typhi of the outbreak. The findings with ampicillin suggested that dosages given were satisfactory. With cephaloridine the concentrations found in patients' sera seemed to show that twice daily doses of 0-5 g. fell short of adequacy.  (+info)

Inhibition of microbial growth by fatty amine catalysts from polyurethane foam test tube plugs. (3/123)

When polyurethane foam test tube plugs are autoclaved, they release volatile fatty amines that inhibit the growth of some microorganisms. The chemical structures of these amines were determined by the use of a gas chromatograph-mass spectrometer. They are catalysts used to produce the foam. The problem of contaminating growth media with toxic substances released from polymeric materials is discussed.  (+info)

Microbial degradation of erythromycins A and B. (4/123)

Growing cultures, as well as broken and lyophilized cells of pseudomonas 56 were found to degrade erythromycin A, and lyophilized cells inactivated erythromycins A and B. The enzyme system involved in this degradation was constitutive and the enzyme level in the cells could be increased about 8-fold when oleandomycin or erythromycin B was added to the growth medium. The ability of whole or broken cells to inactivate erythromycin A was completely lost when these preparations were boiled, and the erythromycin A-inactivating activity was localized in the cell membrane fraction. The lyophilized cells did not degrade oleandomycin, methymycin, tylosin, a mixture of leucomycins, josamycin, or maridomycin III.  (+info)

Production of the Gram-positive Sarcina ventriculi pyruvate decarboxylase in Escherichia coli. (5/123)

Sarcina ventriculi grows in a remarkable range of mesophilic environments from pH 2 to pH 10. During growth in acidic environments, where acetate is toxic, expression of pyruvate decarboxylase (PDC) serves to direct the flow of pyruvate into ethanol during fermentation. PDC is rare in bacteria and absent in animals, although it is widely distributed in the plant kingdom. The pdc gene from S. ventriculi is the first to be cloned and characterized from a Gram-positive bacterium. In Escherichia coli, the recombinant pdc gene from S. ventriculi was poorly expressed due to differences in codon usage that are typical of low-G+C organisms. Expression was improved by the addition of supplemental codon genes and this facilitated the 136-fold purification of the recombinant enzyme as a homo-tetramer of 58 kDa subunits. Unlike Zymomonas mobilis PDC, which exhibits Michaelis-Menten kinetics, S. ventriculi PDC is activated by pyruvate and exhibits sigmoidal kinetics similar to fungal and higher plant PDCs. Amino acid residues involved in the allosteric site for pyruvate in fungal PDCs were conserved in S. ventriculi PDC, consistent with a conservation of mechanism. Cluster analysis of deduced amino acid sequences confirmed that S. ventriculi PDC is quite distant from Z. mobilis PDC and plant PDCs. S. ventriculi PDC appears to have diverged very early from a common ancestor which included most fungal PDCs and eubacterial indole-3-pyruvate decarboxylases. These results suggest that the S. ventriculi pdc gene is quite ancient in origin, in contrast to the Z. mobilis pdc, which may have originated by horizontal transfer from higher plants.  (+info)

Inhibitory effects of citrates in the determination of trace amounts of penicillin. (6/123)

In the microbiological assay for the determination of trace amounts of penicillin, it has been shown that sodium citrate and penicillin act synergistically against Sarcina lutea. The inhibitory action of citrate appears to involve a sequestering of divalent cations essential to the growth of the organism as shown by minimal inhibitory concentration and agar diffusion studies. The addition of calcium or magnesium to broth or agar at various concentrations overcomes this inhibition, and 0.02 M magnesium was found to be the most effective concentration. On agar supplemented with magnesium chloride, penicillin dose-response curves with and without citrate present were practically superimposable, and larger inhibition zones against a greater amount to total growth resulted in improved assay susceptibility and an interference-free method. Misleading results can be obtained when pharmaceutical products containing citrates are tested by conventional methods for penicillin cross-contamination.  (+info)

N-acetyl-L-phenylalanyl-L-phenylalaninol a metabolite of Emericellopsis salmosynnemata. (7/123)

A new metabolite N-acetyl-L-phenylalanyl-L-phenylalaninol was isolated from culture filtrates of Emericellopsis salmosynnemata which produces zervamicins I and II. The structure was assigned from spectral properties and degradative studies.  (+info)

The assay of penicillin in blood-serum using Sarcina lutea. (8/123)

When Sarcina lutea is used as test organism in a cup-plate assay, the dose-response curves for the assay of penicillin in sera of humans and rabbits are linear with the square of the zone diameter and log concentration of penicillin and parallel to the dose-response curve for penicillin in phosphate buffer. Suitable conditions for such assays are described, using either large square assay-plates and fish-spine beads or conventional Petri dishes and cylinders. The assay using large plates and fish-spine beads is much more accurate and economical of effort and serum. An assay method suitable for inclusion in the blood-level duration test for oily injection of procaine penicillin (International Pharmacopoeia) is described. The method makes it possible for fiducial limits to be readily computed for the potencies obtained.  (+info)

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