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PubMed2000

Degradation of pectins with different degrees of esterification by Bacteroides thetaiotaomicron isolated from human gut flora.

A complete human fecal flora and cultures of defined species obtained from fecal flora were investigated in vitro to determine their ability to ferment the dietary fiber pectin. Bacteroides thetaiotaomicron was tested as a pectin-degrading microorganism alone and in coculture with Escherichia coli. Macromolecular pectins with different degrees of esterification were used as substrates in microbial degradation studies. The levels of oligogalacturonic acids formed in batch cultures were estimated during a 24- or 48-h incubation period by using high-performance thin-layer chromatography and high-performance anion-exchange chromatography. The spectrum and the amount of unsaturated oligogalacturonic acids formed as intermediate products of pectin fermentation changed permanently in the culture media during incubation with the complete fecal flora. After 24 h, no oligogalacturonic acids were detected. The pectin-degrading activities of pure cultures of B. thetaiotaomicron were lower than the pectin-degrading activity of a complete fecal flora. Cocultures of B. thetaiotaomicron and E. coli exhibited intermediate levels of degradation activity. In pure cultures of E. coli no pectin-degrading activity was found. Additionally, the rate of pectin degradation was affected by the degree of esterification of the substrate. Saturated oligogalacturonic acids were not found during pectin fermentation. The disappearance of oligogalacturonic acids in the later stages of fermentation with both the complete fecal flora and B. thetaiotaomicron was accompanied by increased formation of short-chain fatty acids.

Bacteroides↗
PubMed1965

Fermentation studies with Streptomyces griseus. I. Carbohydrate sources for the production of protease and streptomycin.

The effects of four carbon sources and inorganic phosphate on the production of streptomycin and protease by a strain of Streptomyces griseus were studied. Protease production was increased in fermentations with comparatively rapid consumption of carbohydrate, and streptomycin was produced under conditions of moderately slow consumption. Starch was consumed more rapidly than glucose, and, in fermentations with starch as a carbon source, good yields of protease were associated with poor yields of streptomycin. The effect of the concentration of inorganic phosphate varied with the sugar source; the rate of consumption of glucose or fructose increased with the addition of inorganic phosphate, and the utilization of starch or maltose was not affected.

Carbohydrate Metabolism↗
PubMed1965

Production of 2,3-butylene glycol from citrus wastes. II. The Bacillus polymyxa fermentation.

The conditions required for production of levo 2,3-butylene glycol by Bacillus polymyxa from citrus molasses were studied. Starter cultures required acclimatization to the substrate prior to inoculation of the fermentation medium. Maximal production of butylene glycol with minimal residual sugar was obtained with a medium consisting of molasses, diluted to 20 degrees Brix, and 0.4% urea. Optimal environmental conditions included aeration at 0.11 volumes of air per volume of medium per minute, maintenance of pH at 6.0 to 6.2, a fermentation temperature of 30 C, and a stirring rate of 420 rev/min. The concentration of butylene glycol obtained in the fermentation beer ranged from 2.3 to 4.4%. The optical rotation of the glycol ranged from [alpha](D) (23 degrees ) = -1.01 degrees to -10.45 degrees . The variation in rotation was probably due to the presence of contaminating substances in the distillate.

Bacillus↗
PubMed1982

Genetic analysis of the pyruvate decarboxylase reaction in yeast glycolysis.

Six different pyruvate decarboxylase mutants of Saccharomyces cerevisiae were isolated. They belong to two unlinked complementation groups. Evidence is presented that one group is affected in a structural gene. The fact that five of the six mutants had residual pyruvate decarboxylase activity provided the opportunity for an intensive physiological characterization. It was shown that the loss of enzyme activity in vitro is reflected in a lower fermentation rate, an increased pyruvate secretion, and slower growth on a 2% glucose medium. The different effects of antimycin A on leaky mutants grown on ethanol versus the same mutants grown on glucose support the view that glucose induces some of the glycolytic enzymes, especially pyruvate decarboxylase.

Antimycin A↗
PubMed2000

Dietary fibre, physicochemical properties and their relationship to health.

Dietary carbohydrates that escape digestion and absorption in the small intestine include non-digestible oligosaccharides (carbohydrates with a degree of polymerisation between three and ten), resistant starch and non-starch polysaccharides. The physiological effects of this heterogeneous mixture of substrates are partly predictable on the basis of their physicochemical properties. Monosaccharide composition and chain conformation influence the rate and extent of fermentation. Water-holding capacity affects stool weight and intestinal transit time. Viscous polysaccharides can cause delayed gastric emptying and slower transit through the small bowel, resulting in the reduced rate of nutrient absorption. Polysaccharides with large hydrophobic surface areas have potentially important roles in the binding of bile acids, carcinogens and mutagens. Ispaghula is capable of binding bile acids through a large number of weak binding sites on the polysaccharide structure, and having greatest effect on the potentially more harmful secondary bile acids deoxycholic acid and lithocholic acid.

Adsorption↗
PubMedDate not supplied

14-epidihydrocochlioquinone B and 14-epicochlioquinone B, antibiotics from fermentations of the ascomycete Neobulgaria pura: structure elucidation and effects on platelet aggregation.

14-Epicochlioquinone B (1) and 14-epidihydrocochlioquinone B (2) were isolated from submerged cultures of Neobulgaria pura (Pers. ex Fr.) Petrak. 14-Epicochlioquinone B is a potent inhibitor of human and bovine platelet aggregation stimulated by different inducers. 14-Epidihydrocochlioquinone B does not inhibit the aggregation of platelets. In addition, both 1 and 2 exhibited cytotoxic and antimicrobial activities.

Animals↗
PubMedDate not supplied

Mariannaepyrone--a new inhibitor of thromboxane A2 induced platelet aggregation.

Mariannaeapyrone ((E)-2-(1,3,5,7-tetramethyl-5-nonenyl)-3,5-dimethyl-6-hydroxy-4H-pyran-4-one) is a new fungal metabolite isolated from fermentations of the common mycophilic deuteromycete Mariannaea elegans. The chemical structure of the 4-pyrone was determined by spectroscopic techniques. Mariannaeapyrone is a selective inhibitor of the thromboxane A2 induced aggregation of human platelets, whereas only weak cytotoxic and antimicrobial effects could be observed.

Blood Platelets↗
PubMed2001

Effect of ruminal microflora on the biotransformation of netobimin, albendazole, albendazole sulfoxide, and albendazole sulfoxide enantiomers in an artificial rumen.

The effect of ruminal flora on the disposition of benzimidazole anthelmintic drugs was studied in dual-flow continuous-culture fermenters (artificial rumens). Six 1,320-mL artificial rumens were inoculated with ruminal fluid and fermentation conditions were maintained constant at 39 degrees C, pH 6.4, solid dilution rate of 5%/h, and liquid dilution rate of 10%/h to simulate standard ruminal fermentation conditions. The study was repeated in two consecutive periods. Two hours after the inoculation of rumen fluid, the fermenters were fed 30 g of a 60:40 forage:concentrate ration. Within each period two fermenters per treatment were immediately dosed with 104 mg of netobimin, 52 mg of albendazole, or 39 mg of albendazole sulfoxide. Concentrations of netobimin, albendazole, albendazole sulfoxide and its enantiomers, and albendazole sulfone were analyzed by high performance liquid chromatography at 0.25, 0.5, 1, 2, 4, 6, and 8 h after dosage. Reductive metabolism by the ruminal bacteria was observed, favoring the production of albendazole, the most potent anthelmintic molecule. No differences in the production or consumption of albendazole sulfoxide enantiomers were observed, indicating that the ruminal bacteria metabolism was not enantioselective. Because benzimidazole anthelmintic drugs are generally administered orally, the ruminal flora play an important role in the bioavailability of these drugs. In our study, increased concentrations of albendazole in the three treatments, due to reductive ruminal biotransformation, suggests that ruminal biotransformation may improve the efficacy of orally administered netobimin, albendazole, and albendazole sulfoxide.

Albendazole↗
PubMed1992

Acaterin, a novel inhibitor of acyl-CoA: cholesterol acyltransferase produced by Pseudomonas sp. A92.

Acaterin, a novel inhibitor of acyl-CoA: cholesterol acyltransferase (ACAT), was isolated from a culture broth of Pseudomonas sp. A92 by Diaion HP-20 column chromatography, solvent extraction and reverse phase HPLC. Spectroscopic analyses of the compound yielded 3-(1-hydroxyoctyl)-5-methyl-2(5H)-furanone as the proposed structure. In the presence of oxidized low density lipoprotein, acaterin inhibited the synthesis of cholesteryl ester in macrophage J774 by 50% at a concentration of 45 microM. Acaterin also inhibited ACAT activity in the rat liver microsomes by 50% at a concentration of 120 microM. Kinetic studies suggested that inhibition of ACAT by acaterin was noncompetitive with respect to oleoyl-CoA.

Animals↗
PubMed1993

Tetrafibricin, a novel fibrinogen receptor antagonist. I. Taxonomy, fermentation, isolation, characterization and biological activities.

Tetrafibricin is a novel fibrinogen receptor antagonist produced by Streptomyces neyagawaensis NR0577. It was isolated from the culture broth by Diaion HP-21 adsorption, MeOH extraction, MCI GEL CHP-20P column chromatography, preparative HPLC and Toyopearl HW-40 SF column chromatography. The physico-chemical properties of tetrafibricin indicated that the structure of tetrafibricin is different from the known peptide fibrinogen receptor antagonists and closely related to the polyene macrolide antibiotics. Tetrafibricin strongly inhibited the binding of fibrinogen to its receptors with an IC50 of 46 nM. It also inhibited ADP-, collagen-, and thrombin-induced aggregation of human platelets with IC50s of 5.6, 11.0 and 7.6 microM, respectively.

Anti-Bacterial Agents↗
PubMed1993

R1128 substances, novel non-steroidal estrogen-receptor antagonists produced by a Streptomyces. I. Taxonomy, fermentation, isolation and biological properties.

New non-steroidal estrogen-receptor antagonists, R1128 A, B, C and D, were isolated from the cultured broth of Streptomyces sp. No. 1128 by solvent extraction, silica gel chromatography, reverse phase chromatography and preparative HPLC. These compounds inhibited estrogen binding to its receptor. The IC50 values of R1128 A, B, C and D for partially purified rat uterine cytosol receptor were 1.1 x 10(-7) M, 1.2 x 10(-7) M, 2.6 x 10(-7) M and 2.7 x 10(-7) M, respectively.

Animals↗
PubMed1993

SCH 45752--an inhibitor of calmodulin-sensitive cyclic nucleotide phosphodiesterase activity.

A highly potent inhibitor of calmodulin-sensitive phosphodiesterase (PDE) activity was isolated from the culture broth of an unidentified fungal isolate, SCF-125. A chemically defined medium was developed for production of this compound. The PDE inhibitor was isolated from the fermentation filtrate by adsorption on a macro-reticular resin and further purified by gel filtration chromatography and reverse-phase HPLC. The major PDE inhibitor was identified as cephalochromin, a bis-naphthopyrone, by spectral data analysis. The compound, SCH 45752, inhibited calmodulin-sensitive PDE activities with IC50 values of 40-47 nM. It inhibited the activities of calmodulin-independent PDE and various protein kinases with higher IC50 values (2-40 microM). SCH 45752 does not appear to be a calmodulin antagonist. Furthermore, SCH 45752 affects smooth muscle contraction at a concentration of 30 microM; it potentiated the relaxing effect of sodium nitroprusside on carotid artery media contracted by histamine. Thus SCH 45752 is one of the most potent inhibitors of calmodulin-sensitive PDE activity known, and it is capable of exerting a pharmacological effect in at least one intact tissue model.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1995

Stachybocins, novel endothelin receptor antagonists, produced by Stachybotrys sp. M6222. I. Taxonomy, fermentation, isolation and characterization.

Stachybocins A, B and C, novel endothelin (ET) receptor antagonists, were isolated from the culture filtrate of Stachybotrys sp. M6222. They were extracted with ethyl acetate and then purified by alumina and silica gel column chromatographies. The molecular formulae of stachybocins were determined to be C52H70N2O10 (stachybocin A) and C52H70N2O11 (stachybocins B and C). It was supposed that they consisted of spirobenzofuran and terpene units from NMR spectra. They showed the inhibitory activity of 125I-ET-1 binding to rate ETA, human ETA and human ETB receptors.

Animals↗