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PubMedDate not supplied

Optimisation of nutritional requirements and process control parameters for the production of HA-2-91, a new tetraene polyene antibiotic.

HA-2-91, a new tetraene polyene antibiotic produced during submerged fermentation of Streptomyces arenae var ukrainiana. Optimisation of nutritional requirements and process control parameters were studied for higher productivity of HA-2-91 during fermentative production in shaken flasks using complex media. Experimental findings indicate that jowar starch (Sorghum vulgare) is the best carbon source while cornsteep liquor in combination with peanut meal are the best nitrogen sources. Exogenous addition of amino acids, divalent cations and fatty acids suppressed the productivity of HA-2-91. Incorporation of glucose into the production medium above 5% (w/v) results in inhibition of productivity of HA-2-91 which may be due to catabolite regulation. The concentration of phosphate ions above 10 ppm also showed similar suppression effect on the productivity of HA-2-91. However, ferrous ions at 100 ppm showed slight stimulatory effect on the production of HA-2-91. The optimum process control parameters for the production of HA-2-91 were found to be temperature, 28 degrees C; inoculum concentration from seed to production medium, 1% (v/v); pH and volume of production medium 6.5 and 100 ml respectively; and fermentation cycle time, 120 hours.

Antifungal Agents↗
PubMed1991

[Ionic channels formed in the lipid bilayer membranes by aureofuscin, a polyene antibiotics].

A chamber filled with salt solution and separated into two compartments by a Teflon partition with a pore of 700 microns diameter was used to investigate the action of aureofuscin, a polyene antibiotics, on a planar lipid bilayer. The pore was covered with a bilayer formed by a N-decane solution of lecithin and cholesterol (20 mg/ml and 5 mg/ml). The electrical property and ionic permeability of the bilayer were studied by using voltage clamp method. Decrease of the bilayer resistance and the channel-like activity could be observed 20 min after the addition of aureofuscin (10-20 micrograms/ml) to one compartment. The existence of a transmembrane voltage and ionic gradient were not necessary for the channel-forming activity of aureofuscin. Discrete current steps were recorded at a concentration of 1.4 micrograms/ml aureofuscin, with a predominant unit conductance of 4-6 pS in a symmetric KCl, solution of 100 mmol/L. By using Goldmann-Hodgkin-Katz voltage equation the ionic selectivity of the channel formed by aureofuscin was estimated by the reversal potential measured in the asymmetrical solution system. The results showed that aureofuscin channels were more permeable to potassium ion than to chloride ion (PK/PCl approximately 5.2). These data may be used to explain the action of aureofuscin on neurotransmitter release and muscle membrane potential in addition to providing some explanation on its curing effect in clinical use.

Chlorides↗
PubMed1991

[Study of components of standard samples of polyene macrolide antibiotics by the methods of high performance liquid chromatography and SIEAP mass spectrometry].

The component composition of reference samples of polyenic macrolide antibiotics such as nystatin, mycoheptin, amphotericin B and levorin was studied by HPLC and chromatographic mass spectrometry in comparison to the WHO standards. It was shown that the samples were close by their component composition to the analogous samples of the WHO standards.

Amphotericin B↗
PubMed1991

[Stability at different pH of polyene antibiotics derived from partricin].

The degradation of a new semisynthetic polyene antibiotic partricin A dimethylamino ethylamide diaspartate (SPA-S-717) at 37 degrees C in water at different pH is studied. It is found to be sensitive to acidic pH and much less sensitive near neutrality. Then a linear relation between pH and logarithm of reaction rate constant is detected. This fact therefore can give some directions as regards the drug somministration in view of pharmacological and clinical trials.

Anti-Bacterial Agents↗
PubMed1990

Stereoselective synthesis and the polyene macrolide antibiotics.

The stereochemical complexity of roflamycoin and other polyene macrolide antibiotics presents a formidable challenge to the synthetic chemist, and the lack of obvious disconnections makes the retrosynthetic analysis very complex. The alternating (1, 3, 5, ...) polyol chain in roflamycoin is difficult to synthesize in part because there is no simple method to assemble these chains from smaller subunits. We have addressed this problem and developed a simple, convergent method for assembling alternating polyol chains. It is designed around a new class of 1,3-diol synthons: 6-alkyl-4-thiophenyl-1,3-dioxanes. These 1,3-diol synthons are readily available from either homoallylic alcohols or beta-hydroxyesters, which are themselves readily prepared in optically pure form. Reduction of these synthons under the appropriate conditions gives configurationally stable alkyllithiums with either syn or anti stereochemistry. Reaction with electrophiles produces protected syn or anti-1,3-diols.

Anti-Bacterial Agents↗
PubMed1986

[Effect of filipin, a polyene antibiotic, on human tumor cell killing in vitro by peplomycin].

Four kinds of cultured human tumor cell lines sensitive or resistant to bleomycin (BLM) were examined for the effect of filipin, a polyene antibiotic, on peplomycin (PEP)-induced cell killing. Although PEP was more effective than BLM against BLM-resistant HeLa cells (HeLa-BLMr), neoplastic cells derived from salivary gland (HSG) and melanoma cells (MEC), these three cell lines were still at least ten times more resistant to PEP than epidermoid carcinoma cell lines including HeLa cells by comparison of IC50, and showed lower cellular accumulation of 3H-PEP as compared with HeLa cells. When these lines were pretreated with filipin, 3H-PEP accumulation by the cells was increased 1.33-, 2.34-, 1.91- and 1.14-fold in HeLa, HeLa-BLMr, HSG and MEC cells, respectively. Combination use of PEP and filipin resulted in a remarkable enhancement of cytocidal effect in HeLa-BLMr and HSG cells (100- and 25-fold decrease of IC50, respectively), and a slight enhancement in HeLa cells, but not in MEC cells. It is therefore suggested that there are differences among cell types in the potentiation of PEP-induced cell killing by filipin.

Bleomycin↗
PubMed1986

[Prostaglandin synthetase activity in the different layers of the kidneys of young rats exposed to polyene antibiotics].

Prostaglandin (PG)-synthestase activity was studied in the cortical, medullary and papillary kidney layers in young rats subjected to prolonged administration of polyene antibiotics (amphotericin B, levorin and nystatin). This activity was markedly increased during the first few hours after the administration of amphotericin B. At later terms a pronounced decline in the enzyme activity was observed. The changes were most prominent in the medullary and papillary layers. The other two antibiotics were less potent. The experimental results have shown that amphotericin B had maximal effect on renal PG-synthetase activity, while the sodium salt of nystatin was least effective.

Amphotericin B↗
PubMed1987

[The type of interaction of polyene antibiotics with antifungal and antibacterial agents].

The combined effect of various polyenic antibiotics and other antifungal and antibacterial drugs on Candida was studied. The efficacy of the combinations was estimated with the method of square titration followed by quantitative plating out of the samples. By the interaction type the combinations were divided into 3 groups. The character of the drug interaction in these groups might be considered as indifferent, additive or synergistic. No antagonistic effect was observed in any of the combinations. The findings may be useful in more successful treatment of candidiasis when monotherapy is not sufficiently efficient, as well as in optimization of schemes for treating mixed infections.

Anti-Bacterial Agents↗
PubMed1978

Mepartricin, a polyene active on both Trichomonas and Candida. Lack of mutagenic activity.

Mepartricin, the methyl ester of partricin, is a new polyene antibiotic with antifungal and antiprotozoal activity. The antitrichomonas activity in vitro is comparable to that of metronidazole, the widely used drug recently demonstrated to possess mutagenic activity and thus to be used with caution in therapy. Clinical investigations have shown that mepartricin can be successfully used in the topic treatment of vaginal trichomoniasis and candidiasis. The mutagenic activity of mepartricin has been evaluated using the Ames' test and compared to that of metronidazole. No mutagenic activity was detected for mepartricin. The drug can thus be proposed as a safer and efficient alternative to metronidazole.

Administration, Topical↗
PubMed1978

[Properties of a Candida albicans strain possessing an increased sensitivity to polyene antibiotics].

Characteristics of a mutant of the yeast-like fungus Candida albicans with increased sensitivity to amphotericin B, levorin and nystatin is presented. Increased sensitivity to the polyens in the isolate must be associated with changes in the cell wall and/or with decreased total viability of the strain. The following factors were in favour of this: presence of significant amounts of pseudomycelial cells with thinner cell walls as compared to the yeast cells in the population of the mutant strain; a higher rate of potassium liberation from the cells of the mutant strain in the presence of amphotericin B; a lower growth rate of the mutant strain on solid and liquid media; an increased death rate of the cells in the intact culture of the mutant strain as compared to the initial strain; absence of changes in the absorption spectrum of sterols isolated from the cells of the mutant strain as compared to the initial culture.

Amphotericin B↗
PubMedDate not supplied

[Effect of polyene antibiotics on the activity of prostaglandin metabolism enzymes in various layers of the kidney in young rats].

Effect of polyenic antibiotics amphotericin B, levorin, nystatin on activity of prostaglandin metabolizing enzymes was studied in cortex, medullar and papillary layers of young rat kidneys. Amphotericin B was shown to exhibit the maximal effect on the enzymatic activity. Distinct "impairing" action of the antibiotics, especially of amphotericin B, was found in medullar and papillary layers of kidney at the end of the experiment carried out within 8 days.

Animals↗
PubMed1986

[Formation of a new polyene antibiotic octamycin by a culture of Actinoplanes ianthinogenes subsp. octamycini].

A culture of Actinoplanes ianthinogenes subsp. octamycini producing a polyenic antibiotic with the UV spectrum characteristic of octaens was isolated. Optimal conditions for biosynthesis of the antibiotic were developed and an active variant 4041-6 producing 2 mg of octamycin per 100 ml of the medium was selected. A procedure for recovery of the antibiotic with the use of Sefadex LH-20 was used. Certain physicochemical characteristics of octamycin were defined. The data on the UV and IR spectra suggested the presence of an alkyl substituent in the octamycin chromophore. The antibiotic showed antitumor activity, sufficient activity against gram-positive bacteria and low activity against fungi and yeasts.

Actinomycetales↗
PubMed1979

[Effect of the polyene antibiotic, roseofungin, on the liberation of the intracellular components from Candida guilliermondii cells and from rat erythrocytes].

Liberation of inorganic ions (potassium and phosphorus), nucleotides and protein from the cells of Candida guilliermondii and rat erythrocytes was studied. It was found that leakage of these components depended on the incubation time, antibiotic dose and amount of the cell material. The potassium ions proved to be most sensitive to the antibiotic: even at low concentrations of roseofungin (2-4 microgram/ml) the amount of the intracellular potassium changed. A decrease in the dry mass and volume concentration in the cells of Candida guilliermondii and lysis in the red blood cells were observed in addition to the leakage of the above intracellular components. The cells of Candida guiliermondii at the beginning of the semilogarithmic growth phase were especially sensitive to roseofungin. The coefficient of roseofungin distribution in the cells of Candida guiliermondü was evaluated. The maximum distribution coefficient was observed at roseofungin concentrations of 40 and 80 microgram/ml for the 4- and 18-hour cultures respectively. Therefore, the effect of roseofungin is characteristic of polyens.

Animals↗
PubMed1979

[Photo-dependent conversions of cytochrome f in bean chloroplasts and leaves treated with polyene antibiotics].

The photo-dependent absorption changes of cytochrome f in bean chloroplasts and native leaves treated with the polyene antibiotics surgumycin and filipin were studied. Upon incubation of the chloroplasts or leaves with the antibiotics the value of the photo-induced signal of cytochrome f decreased considerably; however, the kinetics of the cytochrome oxidation under the effect of the exciting light and dark reduction remained unchanged. An addition of plastocyanin to the suspension of the antibiotic-treated chloroplasts, which contained no artificial donors and acceptors, only slightly increased the absolute value of the photo-induced signal of cytochrome f. An addition of plastocyanin to the chloroplasts containing the dichlorophenolindophenol-ascorbate-methylviologen system, sharply changed the kinetics of the cytochrome f photoconversions. A simultaneous registration of the photo-induced signal of cytochrome f and the photochemical activity of photosystem I of the antibiotic-treated chloroplasts revealed differences in the degree of inhibition of the photosystem I activity and decrease of the absolute value of the cytochrome f signal. The data obtained are discussed in terms of possible alternative pathways of electron transfer in the part of the electron transporting chain under study.

Anti-Bacterial Agents↗
PubMed1982

[Mechanism of polyene antibiotic inactivation. Possible ways for levorin stabilization].

Various means for levorin isolation were studied with the EPR method and approaches to stabilization of the antibiotic on storage under natural conditions were discussed. It was shown that formation of the radicals begins already at the first stage of the antibiotic isolation, i.e. during extraction from the mycelium. Treatment of the solvents with an inert gas or addition of antioxidants decreased the number of free radicals in a freshly isolated product. The antibiotic inactivation rate depended on the initial concentration of the free radicals and conditions of natural storage. The levorin stability increased when oxygen was thoroughly removed from the solvents at all isolation stages and the antibiotic was subsequently stored under conditions preventing any access of the air. The stabilizing effect was also observed when the oxidative effect of the amino sugar moiety on destruction of the polyenic chromophore during the antibiotic complex formation with respect to the amino group was decreased.

Anti-Bacterial Agents↗