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PubMed1991

[Caries-inducing activity of soybean-oligosaccharide (SOR) in vitro and in experimental dental caries of rats].

The caries-inducing activity of soybean-oligosaccharide (SOR: stachyose- and raffinose-rich sugar mixture) was examined in in vitro and in vivo experiments. Streptococcus mutans MT 8148R fermented SOR and produced acids. However Streptococcus sobrinus 6715 did not ferment. SOR was not able to act as a substrate for crude glucosyltransferases (GTase) of these mutans streptococci to synthesize the water-insoluble glucan. However, SOR did not inhibit the synthesis of water-insoluble glucan from sucrose by crude GTase. SOR was proved to be of low cariogenicity in rats infected with S. sobrinus 6715.

Animals↗
PubMed1987

[Simulation of intestinal microbial overgrowth by continuous culture].

By the aid of continuous flow culture of microbial populations it is possible to answer specific micro_ecological questions even under anaerobic conditions. We present some findings from a continuous flow model of human duodenal juice with microbial overgrowth. Germ counts and species were reproducible in a steady state over several days. Metabolic activity was very high. For example, this model allows the in vitro study of therapeutic possibilities against overgrowth syndrome, microbial fermentation of food, metabolism of drugs and the growth of microorganisms on surfaces in gastrointestinal tract.

Bacteria↗
PubMedDate not supplied

Pharmacokinetic characteristics of the new veterinary antibiotic turimycin.

A macrolide antibiotic turimycin, is a fermentation product of Streptomyces hygroscopicus. It is active in vitro against a range of mycoplasma species and gram-positive bacteria. The antimicrobial activity of the agent was determined in serum, urine, feces and extracts of different organs. In rats, dogs and pigs the serum half life of turimycin ranged from 30 to 120 min. The absorption rate from the intestine was about 30%. After a single iv injection of turimycin into rats, the original substance and its metabolites were excreted preferably by the bile. After oral administration of turimycin to pigs (250 mg/kg daily for 14 days) and to flow (650 mg/kg daily for 10 days) antimicrobial activity was detected in fatty tissue and bile up to the 14th posttreatment day. The pharmacokinetic properties of turimycin are similar to those of corresponding macrolide antibiotics, including tylosin.

Animal Diseases↗
PubMed1983

Studies on a new nucleoside antibiotic, dapiramicin. I. Producing organism, assay method and fermentation.

A new antibiotic, dapiramicin, has been isolated from the fermentation broth of Micromonospora sp. SF-1917. Since the dapiramicin exhibited essentially no in vitro activity by usual bioassays, two assay methods for dapiramicin were developed, HPLC and a new bioassay by growth inhibition of fungal mycelia on a slide glass. Fermentation of dapiramicin is also described.

Antifungal Agents↗
PubMed2001

Effects of antecedent fermentative and respiratory growth on the detection of chloramine-stressed Escherichia coil and Salmonella typhimurium.

In vitro laboratory studies were performed to assess the effects of antecedent growth conditions on the recovery of Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028 following chloramine disinfection. Six- and 18-h cultures of each organism were grown under aerobic, fermentative, and nitrate-reducing conditions prior to disinfection. At predetermined time intervals during a 10-min exposure to chloramine, survivors were surface plated on nonselective recovery media to determine C(n)t values. It was observed that nitrate-reducing growth predisposed the test organisms towards an increased sensitivity to chloramine stress over cells grown under fermentation or aerobic conditions (p < 0.01).

Aerobiosis↗
PubMed1988

Lactulose detoxifies in vitro short-chain fatty acid production in colonic contents induced by blood: implications for hepatic coma.

Short-chain (C2-C6) fatty acids constitute the major anions of colonic contents. Acetate is nontoxic in contrast to C(3)4-C6 fatty acids, which induce coma in animals and have been reported to be of importance in the development of hepatic coma in humans. An in vitro fecal incubation system was used to demonstrate how blood, hemoglobin, albumin, lactulose, galactose, fructose, and glucose influence short-chain fatty acid production in the colon. Blood, hemoglobin, and albumin caused increased production of all C2-C6 fatty acids, with the most pronounced increase (fourfold) in C4-C6 fatty acids. Lactulose was converted to acetate only, as were its monosaccharide components, D-galactose and D-fructose. In assays incubated with blood, the production of C4-C6 fatty acids was completely inhibited by lactulose, D-galactose, D-fructose, and D-glucose, respectively, whereas the production of acetate was increased. Lactulose thus "detoxified" the profile of short-chain fatty acids produced in the presence of blood and proteins, indicating that colonic fermentative bacteria prefer lactulose to blood when both substrates are available. The effect of lactulose in the treatment of hepatic coma caused by episodes of gastrointestinal bleeding may therefore be due to a shift in bacterial metabolism from blood or proteins, or both, to lactulose in the colon, resulting in a simultaneous reduction in toxic nitrogenous and organic acid products.

Bacteria↗
PubMed1995

The effect of fibre source and fermentation on the apparent hydrophobic binding properties of wheat bran preparations for the mutagen 2-amino-3,8- dimethylimidazo[4,5-f]quinoxaline (MeIQx).

Preparations of dietary fibre have an ability to bind potentially toxic compounds in vitro, but it is unclear how the measured binding properties are a reflection of either the relative affinity of such compounds for fibre or the saturation binding capacity of the fibre. Cooking and processing of foods and fermentation activity in the colon can result in significant modification of the structure of the fibre matrix. Hence, binding properties measured in vitro may be significantly altered from those at the proposed site of fibre activity. Using cell wall material (CWM) prepared from three distinct wheat fibre sources, the effects of fermentation have been monitored and the consequences on the binding properties assessed. The CWM preparations were feremented for either 0, 6, 18 or 24 h in vitro, using a human faecal inoculum. The coarse bran CWM was also subjected to a simulated gastric treatment. Fermentation resulted in a loss of material from each CWM preparation, the loss being consistent with the bran source, and the maximum extent of fermentation was reached within 18 h. The in vitro binding of the mutagen 2-amino-3,8- dimethylimidazo[4,5-f]quinoxaline (MeIQx) to the unfermented and fermented fibre fractions showed fine bran CWM had a much higher affinity for MeIQx than coarse bran. A 6 h fermentation had little effect on the binding affinity to fine bran, but the affinity for coarse bran became similar to that of the fine bran. Further fermentation for 18 h or 24 h resulted in a further slight increase in the binding affinity for coarse and fine bran, but, more significantly, the binding capacity of each was increased. The binding properties of the beeswing bran were not significantly affected by fermentation. Wheat bran has the potential to bind hydrophobic mutagens in the diet and this potential can be enhanced after fermentation under colonic conditions.

Animals↗
PubMed1998

Bacterial and other biological systems for polyester production.

Poly(3-hydroxybutyric acid) and other structurally related aliphatic polyesters from bacteria, referred to as polyhydroxyalkanoic acids, form biodegradable thermoplastics and elastomers that are currently in use, or being considered for use, in industry, medicine, pharmacy and agriculture. At present, they are produced by microbial fermentations; in the future, production will also be possible by in vitro methods or by agriculture using transgenic plants. Representatives from this highly diverse class of polyesters might be produced as commodity chemicals for bulk applications, and others as fine chemicals for special applications.

Archaea↗
PubMed2006

Effect of chestnut tannin on fermentation quality, proteolysis, and protein rumen degradability of alfalfa silage.

Two experiments were conducted on alfalfa to investigate the effects of the addition of commercial chestnut hydrolyzable tannin at ensiling on 1) silage fermentation quality in lab-scale silos and protein degradation in the rumen, and 2) silage fermentation quality and proteolysis in bale silages. Wilted alfalfa was prepared with 4 tannin levels (0, 2, 4, and 6% on a dry matter (DM) basis; T0, T1, T2, T3, respectively) and ensiled in lab-scale silos. Silages (33% DM) were analyzed for fermentation quality, protein rumen degradability in situ, and organic matter digestibility in vitro through gas production after 120 d of conservation. Wilted alfalfa containing 0 and 4% tannin (T0 and T2) was harvested at 40% DM (wilting level I) and 53% DM (wilting level II) for bale (600 mm diameter) silage. Silages were analyzed for fermentation quality after 78 d of conservation. All the silages were well fermented with no butyric acid. Lab-scale silages showed reductions in ammonia, nonprotein nitrogen (NPN) and DM losses in T2 and T3 treatments, while the fermentation acid profiles were unaffected. In experiment 1, the untreated silage (T0) had the highest protein degradability after being incubated in the rumen. The addition of tannin reduced crude protein ruminal disappearance in a dose-dependent manner. However, the tannin reduced the organic matter digestibility by 5.1% for all of the tannin addition levels. The tannin positively affected the silage quality in the round bale silages, in particular reducing ammonia and NPN in the lowest wilting level. In both experiments, T2 treatment reduced proteolysis without any influence of DM on the binding reaction and reduced the NPN by 15% in comparison to the control.

Ammonia↗
PubMed1998

In vitro prebiotic effects of Acacia gums onto the human intestinal microbiota depends on both botanical origin and environmental pH.

Acacia gums are commonly used food additives. It is currently unclear how extensively these non-digestible polysaccharides are fermented in the human large intestine. However, they have been shown to support bifidobacterial growth in vitro and may represent useful candidate prebiotics. In these investigations, in vitro 24-h batch incubations and chemostat continuous-cultures of human faecal bacteria were conducted using two acacia gums (Fibregum standard and Fibregum AS). Our aim was to study the effects of these gums on bacterial ecology and fermentation in the large bowel. Fructooligosaccharides (Actilight-950P) were also investigated as a reference. Both Acacia gums were extensively fermented by intestinal flora although there were marked differences in fermentation product formation and ecological effects, probably due to their differing botanical origins and/or biochemical characteristics. In particular, fermentation of Fibregum AS led to significantly higher proportions of propionate both in batch and chemostat experiments. Both gums decreased Clostridium sp. levels but only Fibregum-standard induced higher Lactobacillus sp. counts compared to control. These bacterial modifications were highly dependent of the operating pH of the fermentation system with acidic conditions promoting both the prebiotic and the butyrogenic effects of fructooligosaccharides. In these studies, we have demonstrated that, similarly to fructooligosaccharides, Acacia gums can exert putatively beneficial effects on host health through both the improvement of the composition of the large intestine microflora and SCFA formation.

Journal Article↗
PubMed2003

The survival of silage inoculant lactic acid bacteria in rumen fluid.

AIMS: To determine whether lactic acid bacteria (LAB) used in inoculants for silage can survive in rumen fluid (RF), and to identify those that survive best. METHODS AND RESULTS: Twelve commercial silage inoculants were added at 107 CFU ml-1 to strained RF (SRF) taken from dairy cows, with and without 5 g l-1 glucose and incubated in vitro at 39 degrees C. Changes in pH, LAB numbers and fermentation products were monitored for 72 h. In the inoculated RF with glucose, the pH decreased and numbers of LAB increased. The inoculants varied with regard to their effect on pH change and growth. In the SRF, both with and without glucose, the pH values of the inoculated samples were generally higher than those of the uninoculated controls throughout most of the incubation period. This may suggest a positive effect on the rumen environment. CONCLUSIONS: LAB used in silage inoculants can survive in RF in vitro. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first step in studying the probiotic potential of silage LAB inoculants for dairy cattle. The survival of these LAB in RF may enable them to interact with rumen microorganisms and to affect rumen functionality.

Animals↗
PubMed2002

Cardiovascular effects of fermented milk containing angiotensin-converting enzyme inhibitors evaluated in permanently catheterized, spontaneously hypertensive rats.

In this study, two strains of Lactobacillus helveticus were used to produce fermented milk rich in angiotensin-converting enzyme (ACE) inhibitors. In vitro tests revealed that the two milks contained competitive inhibitors of ACE in amounts comparable to what has been obtained in previously reported studies. The two milks were administered by gavage to spontaneously hypertensive rats that had had a permanent aortic catheter inserted through the left arteria carotis, and mean arterial blood pressure and heart rate were monitored from 4 to 8 h after administration. Unfermented milk and milk fermented with a lactococcal strain that does not produce inhibitors were used as controls. Highly significant blood pressure effects were observed; i.e., milk fermented with the two strains of L. helveticus gave a more pronounced drop in blood pressure than the controls. Significant differences in heart rate effects were detected with one of the strains.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Effects of supplemental zinc and manganese on ruminal fermentation, forage intake, and digestion by cattle fed prairie hay and urea.

One in vitro and one in vivo metabolism experiment were conducted to examine the effects of supplemental Zn on ruminal parameters, digestion, and DMI by heifers fed low-quality prairie hay supplemented with urea. In Exp. 1, prairie hay was incubated in vitro for 24 h with five different concentrations of supplemental Zn (0, 5, 10, 15, and 20 ppm) and two concentrations of supplemental Mn (0 and 100 ppm), both provided as chloride salts. Added Mn increased (P < 0.02) IVDMD, but added Zn linearly decreased (P < 0.03) IVDMD. Added Zn tended to increase the amount of residual urea linearly (P < 0.06) at 120 min and quadratically (P < 0.02) at 180 min of incubation, although added Mn counteracted these effects of added Zn. Six 363-kg heifers in two simultaneous 3 x 3 Latin squares were fed prairie hay and dosed once daily via ruminal cannulas with urea (45 or 90 g/d) and with Zn chloride to provide the equivalent of an additional 30 (the dietary requirement), 250, or 470 ppm of dietary Zn. After a 7-d adaptation period, ruminal contents were sampled 2, 4, 6, 12, 18, 21, and 24 h after the supplement was dosed. Supplemental Zn did not alter prairie hay DMI (mean = 4.9 kg/d) or digestibility, although 470 ppm added Zn tended to decrease (P < 0.06) intake of digestible DM, primarily due to a trend for reduced digestibility with 470 ppm supplemental Zn. Zinc x time interactions were detected for both pH (P = 0.06) and NH3 (P = 0.06). At 2 h after dosing, ruminal pH and ruminal ammonia were linearly decreased (P < 0.05; P < 0.01) by added Zn. At 5 h after feeding, ruminal pH was linearly increased (P < 0.05) by added Zn, suggesting that added Zn delayed ammonia release from urea. The molar proportion of propionate in ruminal fluid was linearly and quadratically increased (P < 0.02; P < 0.01) whereas the acetate:propionate ratio was linearly and quadratically decreased (P = 0.02; P < 0.05) by added Zn. Through retarding ammonia release from urea and increasing the proportion of propionate in ruminal VFA, Zn supplementation at a concentration of 250 ppm may decrease the likelihood of urea toxicity and increase energetic efficiency of ruminal fermentation.

Animal Feed↗
PubMed1984

[Rumen fermentation with special reference to volatile fatty acid production during reproduction. 1. Methods and results of volatile fatty acid levels and production rates in vitro].

The target of the investigations was to register part of the synthesis performance in the rumen of ewes during the complete reproduction cycle. With the help of in-vitro experiments with artificial rumen the concentration and production rates of volatile fatty acids in the rumen fluid were measured. From the experiments the measured data of fertility-accentuated crossbreeding (experiment 1) and crossbreeding (experiment 2) ewes were contrasted. The average concentrations of volatile fatty acids in ewes are 95.4 m mol/l in experiment 1 and 109.2 m mol/l in experiment 2 during the early stage gestation, 121.4 m mol/l in experiment 1 and 99.8 m mol/l in experiment 2 in the last stage stage of gestation, 129.6 m mol/l in experiment 1 and 112.8 m mol/l in experiment 2 during lactation and 106.6 m mol/l in experiment 1 and 112.9 m mol/l in experiment 2 during the dry period. The production rates of volatile fatty acids calculated form their concentration amount to 4.8 m mol/l X h in experiment 1 and 2.6 m mol/l X h in experiment 2 in the early stage of gestation, 3.5 m mol/l X h in experiment 1 and 3.1 m mol/l X h in experiment 2 in the last stage of gestation, 3.2 m mol/l X h in experiment 1 and 2.7 m mol/l X h in experiment 2 during lactation and 3.7 m mol/l X h in experiment 1 and 2.9 m mol/l X h in experiment 2 in the dry period. The correlation between the concentration and the production rate of volatile fatty acids is not significantly negative in either of the ewe experiments. The scattering of the individual values is wide so that the individual influence of the test animals as well as the influence of the in-vitro method used permit the conclusion that a significant statement on the influence of the genotype and the stage of reproduction on the production rates cannot be made.

Animals↗
PubMed1990

In-vitro studies with ramoplanin (MDL 62,198): a novel lipoglycopeptide antimicrobial.

Ramoplanin is a novel lipoglycopeptide antimicrobial complex, isolated from the fermentation products of a strain of Actinoplanes sp. (ATCC 33076), which comprises three closely related polypeptides, each containing chlorinated phenyl moieties and D-mannose. The in-vitro activity of ramoplanin was compared with those of vancomycin and teicoplanin. Ramoplanin was very active against Staphylococcus spp., irrespective of methicillin susceptibility, with all isolates inhibited by 1 mg/l or less. Concentrations of vancomycin and teicoplanin required to inhibit the same population of bacteria were 4 and 16 mg/l, respectively. Ramoplanin was also very active against Streptococcus spp. (alpha- and beta-haemolytic species, Str. pneumoniae and Enterococcus faecalis, Corynebacterium spp. (including Cory. jeikeium), Listeria monocytogenes, Gardnerella vaginalis, Propionibacterium acnes and Gram-positive anaerobic bacteria, with all isolates inhibited by 2 mg/l, or less. In general, the activity of ramoplanin against these species was either equal to or only slightly less than teicoplanin and equal to or somewhat greater than vancomycin. With the exception of Bacteroides melaninogenicus and Bact. bivius, ramoplanin was not active against Gram-negative bacteria.

Anti-Bacterial Agents↗
PubMed1998

Unsaturated oligogalacturonic acids are generated by in vitro treatment of pectin with human faecal flora.

Pectins with a degree of esterification (DE) of 95, 66, 34 and 0%, respectively, were incubated in vitro with human faecal flora (pH 7.8). The concentration and composition of oligogalacturonic acids (oligoGalA) generated were determined using high-performance thin-layer chromatography (HPTLC) with UV and colorimetric detection. In the first period of the anaerobic degradation, the pectin macromolecules were fragmented into unsaturated oligoGalA as intermediate products by the action of bacterial pectate lyases. Depending on the incubation time and the DE of pectin, the amount of unsaturated oligoGalA having different degrees of polymerization changed continuously. These oligoGalA were present in the cultures for some hours. Mixtures of unsaturated di-, tri- and tetraGalA were the end products of a pectate lyase action. Later, the oligoGalA disappear as a result of their further fermentation by the gastrointestinal microflora under formation of short-chain fatty acids (SCFA). Low-esterified pectins were depolymerized and fermented faster than the highly esterified by the human faecal flora in vitro. Furthermore, a mixture of unsaturated oligoGalA prepared from pectic acid by the action of pectate lyase from Erwinia carotovora was completely fermented by human faecal flora.

Chromatography, Thin Layer↗
PubMed1995

Synthesis of (+)-dynemicin A and analogs of wide structural variability: establishment of the absolute configuration of natural dynemicin A.

BACKGROUND: Dynemicin A is an exceedingly potent antitumor antibiotic derived from microbial fermentation that cleaves double-stranded B-form DNA in vitro in the presence of activating factors such as NADPH or glutathione. Because of the structural complexity, high reactivity, and scarcity of natural dynemicin A, it has not been feasible to modify the structure to any significant extent. Previous studies have not determined the absolute configuration of the natural product. RESULTS: A multistep route for the preparation of enantiomerically pure, synthetic dynemicin A was developed. The absolute configuration of natural dynemicin was determined by comparing the synthetic drug with dynemicin A derived from fermentation. The route that was developed is highly convergent, as the result of a late-stage coupling reaction that combines two complex synthetic fragments, and has been shown to provide access to non-natural dynemicins of wide structural variability by modifications of these fragments. In this way, several nonnatural dynemicins, unavailable by any other means, were synthesized and shown to have DNA-cleaving activity in the presence of glutathione or NADPH. CONCLUSIONS: Enantiomerically pure dynemicin A is now available by laboratory synthesis. The natural, (+)-enantiomer of dynemicin A is shown to possess the 2S, 3S, 4S, 7R, 8R configuration. A wide variety of heretofore unavailable, active analogs of dynemicin A have been prepared and are found to produce subtle variations in sequence specificity of DNA cleavage compared to the natural product and, of potentially greater significance, display variations in the efficiency of DNA cleavage as a function of the activating agent.

Anthraquinones↗