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At least 19 recordsLinked to original sources
PubMed1977

[Effects of polyene antibiotics and detergents on cell membranes of polyene-sensitive and polyene-resistant strains of Candida albicans].

Various detergents and EPR-probes of 4,4-dimethylspiro[5alpha-androstan-17beta-ol-3,2-(1,3-oxazolidin-3-oxyl)]2CH3OH; 2,2,6,6-tetramethylpalmitoyl-amidopiperidine-1-oxyl and 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinoxyl were used to establish structural differences in the membrane of polyene-sensitive and polyene-resistant strains of C. albicans. It was shown that the type of protein-lipid interactions is modified by the changes in the sterol component of the polyene-resistant strain membranes. This manifests itself in a decrease in sensitivity of membrane alkaline phosphatase for levorin and the detergents, as well as in the alteration of the lipid fluidity pattern of the polyene-resistant strain membranes as compared to the membranes of original culture of C. albicans. Treatment of polyene-sensitive strain membranes with amphotericine B causes more intensive protein-lipid interactions, which is not observed in case of the polyene-resistant strain. It is assumed that C. albicans resistance to polyenes is due to the existence of strong protein-lipid interactions in the membrane coupled with ergosterol substitution by other sterol components.

Alkaline Phosphatase↗
PubMed1978

Polyene macrolide antibiotic cytotoxicity and membrane permeability alterations. I. Comparative effects of four classes of polyene macrolides on mammalian cells.

The relationship between polyene macrolide-induced early membrane damage and cytotoxicity in B1 (hamster), B82 (mouse), and RAG (mouse) cells has been investigated. Filipin (FIL) induced the greatest immediate damage, as monitored by 51Cr release, followed by mediocidin (MED), amphotericin B-deoxycholate (Fungizone) (FZ) and pimaricin (PIM). For long term effect, PIM was the least toxic followed by MED, FZ, and FIL as indicated by 24-hour survival, 72-hour viability, and growth rate of cells. In evaluating polyene macrolide-induced permeability alterations and cytotoxicity two types of interactions with mammalian cells were found: (1) cell toxicity at polyene macrolide levels not eliciting immediate membrane permeability changes; and (2) immediate membrane damage without long range toxicity.

Antibiotics, Antineoplastic↗
PubMed1982

[Mechanism of polyene antibiotic inactivation. Changes in the physicochemical characteristics and the destruction of the polyene chromophore levorin during inactivation].

The results of studying free radicals of some polyenic antibiotics with the EPR method are presented. It is shown that the number of free radicals increased by 100 per cent with a 2-fold decrease in the biological activity. A qualitative change in the EPR spectrum due to the presence of a new radical type was also observed. The changes in the spectral characteristics of levorin allowed one to demonstrate that breaking of the links and formation of the polymer products during oxidative destruction of the polyenic chromophore resulted from attachment of the radicals through the antibiotic double bonds. The data correlate with the results of the quantum-chemical evaluation of the polyenic chromophore.

Anti-Bacterial Agents↗
PubMed1976

Polyene antibiotics. VII. Carbon-13 nuclear magnetic resonance evidence for cyclic hemiketals in the polyene antibiotics amphotericin B, nystatin A1, tetrin A, tetrin B, lucensomycin, and pimaricin1,2.

Carbon magnetic resonance establishes conclusively that six polyene macrolide antibiotics containing keto groups (the heptaene amphotericin B, the tetraene-diene nystatin A1, and the tetraenes tetrin A, tetrin B, pimaricin, and lucensomycin) exist in the hemiketal form in solution. Their spectra all contain a hemiketal carbon's absorption near 97 ppm but lack a keto carbon's absorption near 210 ppm. The non-polyenic macrolide erythromycin, on the other hand, exists in the keto form.

Amphotericin B↗
PubMed1977

Polyene antibiotics. IX. An improved method for the preparation of methyl esters of polyene antibiotics.

An improved general method for the preparation of methyl esters of polyene antibiotics is discussed. Using this method methyl esters of pimaricin, nystatin, eurocidin, hamycin, hamycins A and B, aureofungin, partricins A and B, candimycin, candicidin, and amphotericin B have been prepared and their physical properties are reported. The biological activities of hamycins A and B and their methyl esters are also described.

Anti-Bacterial Agents↗
PubMed1982

[Mechanism of polyene antibiotic inactivation. The effect of amino sugar oxidation on polyene chain destruction].

Changes in the acid-base characteristics of levorin during its inactivation are discussed. It is shown that with a decrease in the biological activity a change in the basic characteristics of the levorin amino sugar moiety takes place. The kinetic studies with model compounds, i. e. octaenic alcohol and glucosamine showed that the processes of their oxidation were interrelated. Oxidation of the amino sugar played the role of an inducing factor in oxidation of the polyenic chromophore and in addition impaired correlation between the extinction specific coefficient of levorin and its biological activity.

Amino Sugars↗
PubMed1984

[Yeast resistance to polyene antibiotics. III. Phenotypic analysis of polyene-resistant sterol mutants of Saccharomyces cerevisiae yeasts].

The pleiotropic effects of nystatin resistant mutations have been studied. It has been shown that resistance to nystatin is often accompanied by temperature-sensitivity and, in some cases, by osmotic remedial sensitivity. The dependence of the expression of the mutations on temperature is demonstrated. A new type of conditional nystatin-dependent mutants is found. All nys2 mutants have a defected membrane and are stained on a methylene blue containing media. At the same time, the mutations under investigation do not affect the respiratory competence and the exoenzyme activity of acid phosphatases.

Anti-Bacterial Agents↗
PubMed1984

Potentiation of antiviral activity of acyclovir by polyene macrolide antibiotics.

The potentiation of the antiviral activity of acyclovir [9-[(2-hydroxyethoxy)methyl]guanine] by polyene macrolide antibiotics has been studied as a function of the macrolide structure. The 12 polyenes chosen for this study represented the major structural groups of these antibiotics and induced in mammalian cells repairable membrane alterations or irreversible cell damage. The potentiating activity of the polyene macrolides was determined based on the differential decrease of in vitro production of infectious virions in the presence of acyclovir alone or in combination with the polyene. Pseudorabies virus, a representative herpesvirus susceptible to acyclovir, was replicated in BHK-21 cells grown in serum-free medium to avoid the interference of serum factors in the polyene macrolide-cell interaction. The potentiation activity of the polyene antibiotics was concentration dependent. The enhancement of the antiviral activity of acyclovir was observed at polyene concentrations which had no direct effect on pseudorabies virus replication in BHK-21 cells. The optimal potentiating concentrations of polyenes were 2 to 15 times lower than that inducing 50% of potassium efflux from BHK-21 cells. The highest potentiating activity was observed for the methyl ester of the trimethylammonium derivative of aureofacin B, which reduced the pseudorabies virus titer by two orders of magnitude. Potentiation by polyene macrolides appeared to coincide with the K+-dependent membrane repair process. The acyclovir potentiating activity was associated with polyene macrolide antibiotics having a large and rigid macrolide ring (amphotericin B and aureofacin). Polyene antibiotics with small and rigid (pimaricin and filipin) or large but flexible (nystatin A1 and lienomycin) macrolide rings showed no potentiation of the antiviral effect of acyclovir.

Acyclovir↗
PubMed2005

Isolation and partial characterization of a cryptic polyene gene cluster in Pseudonocardia autotrophica.

The polyene antibiotics, a category that includes nystatin, pimaricin, amphotericin, and candicidin, comprise a family of very promising antifungal polyketide compounds and are typically produced by soil actinomycetes. The biosynthetic gene clusters for these polyenes have been previously investigated, revealing the presence of highly similar cytochrome P450 hydroxylase (CYP) genes. Using polyene CYP-specific PCR screening with several actinomycete genomic DNAs, Pseudonocardia autotrophica was determined to contain a unique polyene-specific CYP gene. Genomic DNA library screening using the polyene-specific CYP gene probe identified a positive cosmid clone, which contained a DNA fragment of approximately 34.5 kb. The complete sequencing of this DNA fragment revealed a total of seven complete and two incomplete open reading frames, which were found to be highly similar, but still unique, when compared to previously known polyene biosynthetic genes. These results suggest that the polyene-specific screening approach may constitute an efficient method for the isolation of potentially valuable cryptic polyene biosynthetic gene clusters from various rare actinomycetes.

Actinomycetales↗