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At least 541 records · Page 30Linked to original sources

Antibiotics from basidiomycetes. IX. Oudemansin, an antifungal antibiotic from Oudemansiella mucida (Schrader ex Fr.) Hoehnel (Agaricales).

From mycelial cultures of Oudemansiella mucida a crystalline optically active antibiotic, oudemansin (2), has been isolated; its structure is closely related to strobilurin A (1). The relative configuration of oudemansin have been determined by X-ray analysis. The antibiotic exhibits strong antifungal properties and inhibits respiration in fungi, cells of the ascitic form of EHRLICH carcinoma, and rat liver mitochondria.

Agaricales↗

Amauromine, a new vasodilator. Taxonomy, isolation and characterization.

Amauromine is a new alkaloid with vasodilating activity obtained from the culture broth of Amauroascus sp. No. 6237. Its molecular formula was determined to be C32H36N4O2 on the basis of elementary analysis and high resolution mass spectroscopic measurement. It has low toxicity in mice.

Alkaloids↗

Biosynthesis of fluorothreonine and fluoroacetic acid by the thienamycin producer, Streptomyces cattleya.

An antimetabolite, THX, was isolated from fermentation broths of the thienamycin producer, Streptomyces cattleya, when the organism was grown in the presence of a fluorine-containing substrate. THX was subsequently identified as one of the four possible stereoisomers of 4-fluorothreonine. Inorganic fluoride or any one of a number of organofluorine compounds can be used as precursors of 4-fluorothreonine. In addition, 19F NMR has provided evidence that the organism synthesizes fluoroacetate under the same fermentation conditions. The in vitro antibacterial spectrum of 4-fluorothreonine is also presented.

Animals↗

WS-9659 A and B, novel testosterone 5 alpha-reductase inhibitors isolated from a Streptomyces. I. Taxonomy, fermentation, isolation, physico-chemical characteristics.

WS-9659 A and B, produced by Streptomyces sp. No. 9659, were extracted from cultured broth, purified by solvent extraction followed by chromatography on silica gel and then isolated as prisms (C22H24N2O, mp 161 approximately 162 degrees C, C22H23N2OCl, mp 152 approximately 153 degrees C). WS-9659 A and B have testosterone 5 alpha-reductase inhibitory activity. The IC50 values of WS-9659 A and B for partially purified rat prostate testosterone 5 alpha-reductase were 5.0 x 10(-7) M and 1.0 x 10(-5) M, respectively.

5-alpha Reductase Inhibitors↗

Tirandalydigin, a novel tetramic acid of the tirandamycin-streptolydigin type. I. Taxonomy of the producing organism, fermentation and biological activity.

Tirandalydigin is a new tetramic acid antibiotic which was discovered in a screen designed to find compounds with activity against pathogenic anaerobic bacteria. It was named tirandalydigin because it possesses structural features that are common to both tirandamycin and streptolydigin. The producing culture, strain AB 1006A-9, is a Streptomyces and was compared to the streptomycetes that synthesize tirandamycin and streptolydigin. It is closely related to the former culture and was named Streptomyces tirandis subsp. umidus. Tirandalydigin has MICs in the range of 0.5 to 32 micrograms/ml against many pathogenic anaerobes, streptococci, enterococci and legionellae.

Aminoglycosides↗

Aselacins, novel compounds that inhibit binding of endothelin to its receptor. I. The producing organism, fermentation and biological activity.

A radioligand test to detect inhibitors of endothelin-1 binding to its receptors in bovine atrial and porcine cerebral membranes was used to screen fungal metabolites from stationary fermentations. Inhibitory activity, observed in culture extracts of two Acremonium species, led to the discovery of aselacins A, B and C. Aselacin A inhibits binding to both membrane fractions with IC50s of approximately 20 micrograms/ml.

Acremonium↗

New isochromophilones VII and VIII produced by Penicillium sp. FO-4164.

New isochromophilones VII and VIII were isolated from the culture broth of Penicillium sp. FO-4164. The structures were elucidated as 6H-2-benzopyran-6,8(7H)-dione, 5-chloro-3-(3',5'-dimethyl-1',3'-heptadienyl)-1,7,8a-trihydro-7, 8a-dihydroxy-7-methyl-7-acetate for isochromophilone VII and 6H-2-benzopyran-6-one,5-chloro-3-(3',5'-dimethyl-1', 3'-heptadienyl)-1,7,8,8a-tetrahydro-7,8-dihydroxy-7-methyl-8-acetate for isochromophilone VIII. Isochromophilones VII and VIII inhibited diacylglycerol acyltransferase activity with IC50 values of 20.0 and 127 microM and acyl-CoA: cholesterol acyltransferase activity with IC50 values of 24.5 and 47.0 microM, respectively.

Acyltransferases↗

BE-31405, a new antifungal antibiotic produced by Penicillium minioluteum. I. Description of producing organism, fermentation, isolation, physico-chemical and biological properties.

A new antifungal antibiotic, BE-31405, was isolated from the culture broth of a fungal strain, Penicillium minioluteum F31405. BE-31405 was isolated by adsorption on high porous polymer resin (Diaion HP-20), followed by solvent extraction, precipitation and crystallization. BE-31405 showed potent growth inhibitory activity against pathogenic fungal strains such as Candida albicans, Candida glabrata and Cryptococcus neoformans, but did not show cytotoxic activity against mammalian cells such as P388 mouse leukemia. The mechanism studies indicated that BE-31405 inhibited the protein synthesis of C. albicans but not of mammalian cells.

Animals↗

Beauveriolides, specific inhibitors of lipid droplet formation in mouse macrophages, produced by Beauveria sp. FO-6979.

Beauveria sp. FO-6979, a soil isolate, was found to produce inhibitors of lipid droplet formation in mouse peritoneal macrophages. A new compound beauveriolide III was isolated along with a known compound beauveriolide I from the fermentation broth of the producing strain by solvent extraction, ODS column chromatography, silica gel column chromatography and preparative HPLC. Beauveriolides I and III caused a reduction in the number and size of cytosolic lipid droplets in macrophages at 10 microM without any cytotoxic effect on macrophages.

Animals↗

(2R-trans)-2-butyl-5-heptylpyrrolidine as a potent sigma receptor ligand produced by Streptomyces longispororuber.

A potent sigma (sigma) receptor ligand was isolated from the culture broth of Streptomyces longispororuber #525. The active compound was identified to be (2R-trans)-2-butyl-5-heptylpyrrolidine by spectroscopic and chemical studies. The compound exhibited high affinity and selectivity for sigma receptors. The IC50 values toward sigma1, sigma2 and dopamine D2 receptors were 2.0, 22.7 and more than 40,000 nM, respectively. Its (2S-trans)- and (+/-)-cis-isomers, both synthesized, were also found to be high affinity sigma ligands.

Animals↗

Effect of nisin and monensin on rumen fermentation in the artificial rumen.

The objective of this study was to investigate the effect of nisin and monensin on rumen fermentation of diets containing hay and barley (80:20%) in artificial rumen (Rusitec system). The Rusitec system consisted of four fermentation vessels (V1, V2, V3, V4): V1 was without additives (control), V2 received daily 2 mg of nisin, V3 involved 5 mg of monensin and V4 combination of 2 mg of nisin with 5 mg of monensin. After an adaptation period (7 days), the fermentation parameters were determined for six consecutive days. Compared to control diet, the addition of nisin resulted in an increase (P < 0.05) of hemicellulose degradation, acetate, propionate (mmol.day-1) production and energetic efficiency of VFA (E), decrease of butyrate production. Nisin had no effect on dry matter (DM), organic matter (OM), cellulose and detergent fiber degradation, production of total gas, methane and efficiency of microbial synthesis. The addition of monensin resulted in an decrease of DM, OM (P < 0.05), cellulose, hemicellulose, detergent fiber degradation (P < 0.001), total gas, methane and ammonia nitrogen (NH3-N) production. Monensin also significantly decreased acetate, butyrate, L-lactate (mmol.day-1) production and it increased propionate production (P > 0.001) and efficiency of microbial synthesis. The combined effect of nisin and monensin in V4 was similar to the effect of monensin in V3 compared to control. Then, the effect of additive monensin was dominant over nisin. In conclusion, our results indicate that nisin was less effective than monensin on some fermentation parameters (important for the improvement of the efficiency of utilization of the diet by ruminants) in artificial rumen.

Animal Feed↗

Effect of Tween 80 and monensin on ruminal fermentation of the diet containing 70% wheat straw treated by white-rot fungus in artificial rumen.

The objective of this study was to investigate the effect of Tween 80 and monensin on rumen fermentation of the diet containing 70% wheat straw treated by white-rot fungus Pleurotus tuber-regium (TWS-PT) and 30% barley in artificial rumen (RUSITEC). The RUSITEC consisted of four fermentation vessels (V1, V2, V3, V4): V1 was without additives (control), V2 received daily 10 mg of monensin, V3 received daily 0.5% Tween 80 (vol.wt-1) and V4 involved the combination of 10 mg of monensin with 0.5% Tween 80 (vol.wt-1). After an adaptation period (6 days) the fermentation parameters were determined for six consecutive days. Tween 80 did not affect the rumen fermentation of the diet consisting 70% TWS-PT and 30% barley in RUSITEC. Monensin affected the rumen fermentation of the diet by the decreased degradability of DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, cellulose (p < 0.001), the decrease of methane production (p < 0.001) and the higher proportion of propionate within the volatile fatty acids (p < 0.001) in comparison to control. Tween 80 did not improve the potency of monensin. Only some indices of the increase mol% of propionate (about 3.4%) and the decrease of methane production (about 0.47 mmol.day-1) were found by using Tween 80 plus monensin in comparison to use of monensin alone.

Animal Feed↗

[Effect of monensin (USA, Czechoslovakia, Bulgaria) on fermentation of animal feed in an artificial rumen (Rusitec)].

An experiment was made with the Rumen Simulation Technique (Rusitec) in which the fermentation of a mixed ration of hay (12.8 g/d) and bruised barley (3.2 g/d) was compared with the fermentation of the same diet in the presence of 5 mg monensin/d from the USA, CSFR and Bulgaria. The fermentation of the mixed ration was significantly affected by all three kinds of monensin. The digestibility of dry matter (DM) in the rations declined in the presence of monensin from 48% to 40% (tab. I). The digestibility of detergent fibre, cellulose and hemicellulose also declined in the presence of monensin (tab. I). The production of methane decreased (-70%) and CO2 production dropped too, but this decrease could be accounted for by the changes in the production of volatile fatty acids and redistribution of metabolic hydrogen (tab. I). Monensin decreased the production of total volatile fatty acids (-21%), the production of acetic (-35%), n-butyric, n-valeric and isovaleric acids (tab. II) and increased the production of propionic acid (+60%). The production, utilization and recovery of metabolic hydrogen were significantly increased in the presence of all three kinds of monensin (tab. IV). The end products of fermentation were affected by an addition of monensin to the mixed ration. All three kinds of monensin increased energic efficiency of volatile fatty acids, decreased adenosinetriphosphate (ATP) production, the amounts of fermented hexose, organic matter fermented and utilization of glucose (tab. III).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

[The effect of monensin on the fermentation of feed with different proportions of hay and concentrate in an artificial rumen (rumen simulation technic)].

An experiment was conducted with rumen pouch (RUSITEC--Rumen Simulation Technique). In four fermentation vessels (V), percent proportions of hay and barley were as follows: V1--40:60, V2 - 60:40, V3--80:20 and V4--100:0. Every day 5 mg of monensin dissolved in 1 ml 96% ethanol were added to each fermentation vessel. All diets were isonitrogenous, and after an addition of urea the crude protein (CP) content made 13% in each diet. The experiment lasted 12 days: so called steady state period took the first six days when the fermentation conditions were stabilized. Monensin reduced dry matter digestibility, production of total volatile fatty acids, acetic acid, n-butyric and isovaleric acids and acetate: propionate proportion, and it increased the production of propionic and n-valeric acids. The production of methane and CO2 decreased. The higher proportion of hay in diets decreased dry matter digestibility, digestibility of detergent fibre, total and individual volatile fatty acids, CO2, methane energy yield of volatile fatty acids (E), glucose utilization, production of adenosine triphosphate and production of fermented hexoses. The production, utilization and recovery of metabolic hydrogen also decreased. The effectiveness of microbial matter synthesis (YATP = 11.3) was highest during the fermentation of feed containing 60% hay and 40% barley.

Animal Feed↗

[Correlations between lactose-fermenting capacity, sensitivity to antibiotics and bacteriophage types of Salmonella agona strains].

Correlation between the ability to ferment lactose, sensitivity to chemotherapeutic agents and phage type of lactose fermenting and nonfermenting S. agona strains was shown in this study. The difference in sensitivity of two S. agona variants toward gentamicin, tobramycin and chloramphenicol was shown. Lactose fermenting S. agona strains were resistant to the above listed antibiotics. The percentage of the resistant strains was 95.3%, 96.9% and 95.3%, respectively. S. agona strains typable by biochemical tests were more often sensitive to those antibiotics. The percentage of the resistant strains of S. agona with typical biochemical properties was for gentamicin 19.4%, tobramycin 3.7% and chloramphenicol 6.7%. Moreover, the percentage of lactose fermenting S. agona strains resistant to seven other out of seventeen tested antibiotics was 83.8% on average and it was 20% higher than percentage of biochemically typical S. agona strains resistant to the same antibiotics. Lactose fermenting S. agona strains belonged almost four times more frequently to subtype VB and also more often to phage type XI; on the other hand six times rare to phage type I in comparison to biochemically typical S. agona strains.

Anti-Bacterial Agents↗

[Study of the conditions for reproducing the processes of antibiotic biosynthesis. Calculating the process of sisomycin biosynthesis].

Conditions were experimentally studied for reproducing sisomicin biosynthesis by up-to-down scaling. It was shown that respiration intensity as a parameter of antibiotic biosynthesis scaling-down had certain limitations connected with multistage oxygen mass transfer. The parameter could be used only when the limiting stages of oxygen mass transfer coincided. It was confirmed experimentally that it was possible to apply the previously proposed theoretical method to estimation of the limiting stage of oxygen mass transfer.

Air↗