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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↗
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↗
PubMed1986

Effect of variation of retinal polyene side-chain length on formation and function of bacteriorhodopsin analogue pigments.

The effect of the length of the retinal polyene side chain on bacterioopsin pigment formation and function has been investigated with two series of synthetic retinal analogues. Cyclohexyl derivatives with polyene chains one carbon longer and one or more carbons shorter than retinal and linear polyenes with no ring have been synthesized and characterized. Compounds of six carbons or less in the polyene chain form pigments very poorly or not at all with bacterioopsin. Compounds containing at least seven carbons in the chain are found to form reasonably stable bacterioopsin pigments that show a small shift in absorbance on irradiation. However, photocycling and proton photorelease are not detected. The analogue with nine carbons in the polyene chain (one less than retinal) forms a stable pigment with an M-type intermediate but demonstrates reduced amounts of photocycling and light-activated proton release. The analogue with a polyene chain identical with that of retinal, but containing no ring, forms a pigment that shows both an efficient light-activated proton photocycle and release. The pigment containing the chromophore with the polyene chain one carbon longer than retinal is likewise fully active. We thus conclude that the length of the polyene chain must be at least 9 carbons for the formation of a stable pigment that photocycles and must be 10 carbons for both the photocycle and light-activated proton release to have a high quantum efficiency.

Bacteriorhodopsins↗
PubMed1992

Synthetic carotenoids, novel polyene polyketones and new capsorubin isomers as efficient quenchers of singlet molecular oxygen.

Novel synthetic polyene polyketones and new synthetic capsorubin isomers were examined for their ability to quench singlet molecular oxygen (1O2) generated by the thermodissociation of the endoperoxide of 3,3'-(1,4-naphthylene) dipropionate (NDPO2). C28-polyene-tetrone (1) exhibits the highest physical quenching rate constant with 1O2 (kq = 16 x 10(9) M-1 s-1). For comparison, the rate constant for the most efficient biological carotenoid, lycopene (3) is kq = 9 x 10(9) M-1 s-1 and that of beta-carotene (5) kq = 5 x 10(9) M-1 s-1. The presence of two oxalyl chromophores at the ends of the polyene chain seems to enhance the 1O2 quenching ability in the C28-polyene-tetrone (1). C28-polyene-tetrone-diacetal (2) (kq = 9 x 10(9) M-1 s-1) and C40-epiisocapsorubin (4) (kq = 8 x 10(9) M-1 s-1) also have high 1O2 quenching abilities. Two carotenoids from plants, phytoene and phytofluene, were much less efficient, kq values being below 10(7) M-1 s-1. Due to the very high singlet oxygen quenching abilities, C28-polyene-tetrone (1), C28-polyene-tetrone-diacetal (2) and C40-epiisocapsorubin (4) may have potential use in preventing 1O2-induced damage in biological and non-biological systems.

Carotenoids↗
PubMed1979

Polyene macrolide antibiotic cytotoxicity and membrane permeability alterations. II. Phenotypic expression in intraspecific and interspecific somatic cell hybrids.

Cytotoxicity and membrane permeability alterations induced by the polyene macrolide antibiotics filipin (FIL) and pimaricin (PIM) have been compared in parental intraspecific and interspecific somatic cell hybrids. B82 (mouse) and B1 (hamster) cells were found to be more resistant than RAG (mouse) parental cells to both polyene macrolides as indicated by 24-hour survival, 72-hour viability, and growth rate. Analysis of both intraspecific and interspecific somatic cell hybrids indicated that polyene macrolide resistance was being expressed even in the presence of the polyene macrolide-sensitive (RAG) genome. Where one of the two parental cell types is relatively polyene macrolide resistant, the use of specific polyene macrolides may prove efficacious as half-selective agents in cell hybridization.

Animals↗
PubMed1979

[Effect of polyene antibiotics and their perhydrovderivatives on intact cells and protoplasts of yeast Candida guilliermondii].

Perhydroderivatives of polyene antibiotics have a much lower activity against eukaryotic cells than the polyene antibiotics itself. Bacterial cells are normally resistant against most polyene antibiotics and their perhydroderivatives. In earlier experiments with wall less L-form cells of Escherichia coli we have shown that the bacterial cell wall may be responsible for the resistance of the intact bacterial cells against polyene antibiotics and their perhydroderivatives by masking internal target sites. In the present paper we studied the effect of polyene antibiotics and their perhydroderivatives on intact cells and protoplasts of Candida guilliermondii. Our experiments have shown that most of the perhydroderivatives studied had a lower activity against intact cells as well as protoplasts than the corresponding polyene antibiotics. This means that in the case of eukaryotic cells the cell wall as a penetration barrier cannot mainly be responsible for the low activity of perhydroderivatives. The results are compared with those obtained previously with intact cells and protoplast type L-form cells of E. coli.

Anti-Bacterial Agents↗
PubMed1986

How do the polyene macrolide antibiotics affect the cellular membrane properties?

In the 1970's great strides were made in understanding the mechanism of action of amphotericin B and nystatin: the formation of transmembrane pores was clearly demonstrated in planar lipid monolayers, in multilamellar phospholipid vesicles and in Acholeplasma laidlawii cells and the importance of the presence and of the nature of the membrane sterol was analyzed. For polyene antibiotics with shorter chains, a mechanism of membrane disruption was proposed. However, recently obtained data on unilamellar vesicles have complicated the situation. It has been shown that: membranes in the gel state (which is not common in cells), even if they do not contain sterols may be made permeable by polyene antibiotics, several mechanisms may operate, simultaneously or sequentially, depending on the antibiotic/lipid ratio, the time elapsed after mixing and the mode of addition of the antibiotic, there is a rapid exchange of the antibiotic molecules between the vesicles. Although pore formation is apparently involved in the toxicity of amphotericin B and nystatin, it is not the sole factor which contributes to cell death, since K+ leakage induced by these antibiotics is separate from their lethal action. The peroxidation of membrane lipids, which has been demonstrated for erythrocytes and Candida albicans cells in the presence of amphotericin B, may play a determining role in toxicity concurrently with colloid osmotic effect. On the other hand, it has been shown that the action of polyene antibiotics on cells is not always detrimental: at sub-lethal concentrations these drugs stimulate either the activity of some membrane enzymes or cellular metabolism. In particular, some cells of the immune system are stimulated. Furthermore, polyene antibiotics may act synergistically with other drugs, such as antitumor or antifungal compounds. This may occur either by an increased incorporation of the drug, under the influence of a polyene antibiotic-induced change of membrane potential, for example, or by a direct interaction of both drugs. That fungal membranes contain ergosterol while mammalian cell membranes contain cholesterol, has generally been considered the basis for the selective toxicity of amphotericin B and nystatin for fungi. Actually, in vitro studies have not always borne out this assumption, thereby casting doubt on the use of polyene antibiotics as antifungal agents in mammalian cell culture media.(ABSTRACT TRUNCATED AT 400 WORDS)

Amphotericin B↗
PubMed1975

[Possibility of the early identification of polyene antibiotic producers].

A method for identification of polyenic antibiotics at early stages of their screening was developed using the known fact of high affinity of polygens and steroids. It was found that addition of cholesterol or ergosterol to the nutrient medium in a concentration of 100 gamma/ml eliminated the inhibitory effect of the polyenic antibiotics. Screening of the antibiotic-producing actinomycetes simultaneously on 2 media, i.e. with and without cholesterol using the yeast test-organisms provided identification of actinomycetes producing polyenic antibiotics. The selective capacity of 3 yeast cultures, i.e. Sacch. cerevisiae, Cand. albicans and Tor. globosa 11-3 as test-organisms for screening polyenic antibiotics was compared. It was shown that mitochondrial mutant 11-3 of Tor. globosa was a highly sensitive model for identification of actinomycetes producing polyenic antibiotic, since 23% of the actinomycetes possessing an activity against that organism produced substances of the polyenic nature. All the strains of the actinomycetes screened with the help of Cand. albicans and Sacch. cerevisia were the same as those detected with the help of mutant 11-3 of Tor. globosa.

Anti-Bacterial Agents↗