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PubMed2000

In vivo measurement of colonic butyrate metabolism in patients with quiescent ulcerative colitis.

BACKGROUND: Butyrate, a short chain fatty acid produced by bacterial fermentation, is a major fuel source for the colonocyte. In vitro work has shown that ulcerative colitis may be characterised by a metabolic defect in colonocyte butyrate oxidation. AIMS: To investigate the rate of metabolism of rectally administered butyrate in patients with quiescent colitis. METHODS: [1-(13)C]-butyrate enemas were administered to 11 patients with long standing quiescent ulcerative colitis and to 10 control patients. The rate of production of (13)CO(2) in exhaled breath over four hours was measured by isotope ratio mass spectrometry combined with indirect calorimetry in order to measure CO(2) production. This allowed calculation of the patients' resting energy expenditure and respiratory quotient. RESULTS: Over a four hour period, 325 (SEM 21) micromol (13)CO(2) was recovered in breath samples from the colitis group compared with 322 (17) micromol from the control group (NS). The respiratory quotient of the colitic group was significantly lower than that of the control group. CONCLUSION: There was no difference in the rate of metabolism of butyrate between the two groups. It is unlikely that there is a primary metabolic defect of butyrate metabolism in patients with quiescent ulcerative colitis.

Adult↗
PubMedDate not supplied

Effects of deoxycholic acid and butyrate on mucosal prostaglandin E2 release and cell proliferation in the human sigmoid colon.

BACKGROUND: A high-fat, low-fiber diet resulting in increased excretion of fecal secondary bile acids is regarded as a major risk factor for colon cancer. Incubation of human colonic biopsies with the secondary bile acid deoxycholic acid (DCA) leads to hyperproliferation with expansion of the proliferative zone, ie, a biomarker of increased cancer risk. Antiproliferative effects on various colon cancer cell lines, however, were reported for butyrate (BUT), a fermentation product of dietary fiber. METHODS: In the following in vitro study we incubated biopsies from the normal sigmoid colon of 12 patients (age 55.8 +/- 3.6 years) with 5 microM DCA or a combination of 5 microM DCA plus 10 mM BUT (DCA/BUT) and determined epithelial proliferation by bromodeoxyuridine immunohistochemistry. As a possible mediator for the DCA effects on colonic cell proliferation, mucosal prostaglandin E2 (PGE2) release into the incubation medium was measured by 125I-PGE2 radioimmunoassay. RESULTS: Incubation with DCA alone revealed a significantly higher labeling index for the whole crypt (.17 vs .11, p < .01) and for the upper 40% of the crypt (.05 vs .01, p < .01) compared with DCA/BUT. Mucosal PGE2 release during DCA/BUT incubation showed a trend toward lower values compared with DCA incubation (357.07 vs 434.29 pg/mg per hour; p = .07). CONCLUSION: The results indicate a normalization of DCA-induced hyperproliferation of colonic epithelium by butyrate that is not clearly mediated by PGE2. Considering that nutrition affects the luminal concentrations of DCA and butyrate, our findings may have implications for colonic carcinogenesis.

Bromodeoxyuridine↗
PubMed1999

New potent antioxidative o-dihydroxyisoflavones in fermented Japanese soybean products.

A potent antioxidative 6-hydroxydaidzein (6-OHD) was newly isolated from soybean koji fermented with Aspergillus oryzae. 6-OHD, in addition to 8-hydroxydaidzein and 8-hydroxygenistein, were found to be present in various fermented soybean products, including their koji. Considering that these o-dihydroxyisoflavones had strong antioxidative activities, they may contribute to protecting from oxidative deterioration during the processing of fermented soybean products.

Antioxidants↗
PubMed1991

Bifidobacterium from fermented milks: survival during gastric transit.

Two Bifidobacterium strains contained in two different fermented milks behave very differently when exposed to an in vitro simulated gastric environment. One strain survives very well during at least 90 min (greater than 10(7)/g), but the second strain studied is much less resistant. These in vitro results, with slight differences, were confirmed by an in vivo study in humans. The assessment of the gastric emptying rate of these products allows an estimation of the amount of Bifidobacterium that may pass into the small intestine.

Adult↗
PubMed1992

Pharmacological probes of Ras function.

Numerous approaches toward anti-ras drugs are being explored. Efforts range from cell-based assays which screen fermentation products to more structural or mechanism-based in vitro screening and design. For the mechanism-based approaches, extensive research efforts on the function and regulation of the ras oncogene protein have identified potential points of intervention, including protein expression, membrane localization, guanine nucleotide activation, and interaction with effector systems.

Genes, ras↗
PubMed2004

Modulation of Kupffer cell activity: physio-pathological consequences on hepatic metabolism.

Classically, the maintenance and control of liver homeostasis are assigned to the metabolic activity of parenchymal cells. However, recent evidence highlights complex and tightly regulated interactions between hepatocytes and other intra-hepatic cells. Kupffer cells--the resident macrophages of the liver--are able to release a tremendous array of mediators upon inflammatory conditions, such as infection, and their role in innate immunity is well described in the literature. However, the impact of these Kupffer cell-derived mediators on liver homeostasis is unknown. In this study, we investigated the physiological involvement of Kupffer cells in the regulation of hepatic metabolism. It was first necessary to validate the use of a compound able to selectively deplete Kupffer cells. We confirmed that gadolinium chloride (GdCl3) injection to rats eliminated ED2-positive Kupffer cells and strongly decreased both their phagocytic and peroxidase activities. Moreover, we demonstrated that precision-cut liver slices (PCLS)--an original in vitro model allowing to maintain intact hepatic architecture and cellular heterogeneity--obtained from GdCl3-treated rats released lower amounts of inflammatory mediators. Therefore, we proposed to use GdCl3 prior to PCLS preparation in order to investigate the role of Kupffer cells in the control of hepatic metabolism. Among various metabolic functions of the liver, we focused, in particular, on paracetamol and lipid metabolism as example of drug and intermediary metabolism, respectively. Our results suggest that the presence of Kupffer cells in liver tissue can affect the viability of PCLS in culture and are involved in the regulation of paracetamol metabolism, in particular the glucuronidation pathway. Furthermore, inhibition of Kupffer cells leads to a metabolic shift of fatty acids towards their esterification (at least, in fasted rats) and accumulation in the liver tissue, supporting a key role of Kupffer cells in the regulation of intra-hepatic lipid metabolism. Results obtained from in vitro studies suggest that Kupffer cell-derived prostaglandin E2 might be involved in the higher capacity of lipid synthesis observed in PCLS obtained from GdCl3-treated rats. Final objectives of this work were devoted to highlight the impact of the diet on Kupffer cell activity, offering possibilities to modulate Kupffer cell functions by nutrients under various physio-pathological conditions, such as inflammation. Our results demonstrate that a supplementation of glycine, a simple amino acid, in the diet could influence lipid metabolism, namely in the liver. A direct relationship between those metabolic effects and Kupffer cell activity has not been demonstrated. Nevertheless, we have shown that the use of glycine in vitro offers the possibility to elucidate complex interactions between Kupffer cells and hepatocytes, by using PCLS in culture, and could constitute an alternative tool to inhibit in vitro Kupffer cell-derived mediators. Furthermore, dietary oligofructose, a fermentable and nondigestible carbohydrate known as prebiotic, was able to increase phagocytic activity of the liver and the production of Kupffer cell-derived mediators by PCLS. Our results indicate that improvement of Kupffer cell activities might be involved in the hepatoprotection against septic challenge observed after a diet enriched with oligofructose.

Animals↗
PubMed1995

Bio-Catalyzer alpha . rho No. 11 (Bio-Normalizer) supplementation: effect on oxidative stress to isolated rat hearts.

Bio-Catalyzer alpha . rho No. 11 (Bio-Normalizer), a natural health food product prepared by yeast fermentation of medicinal plants, has been recently reported to possess antioxidant properties. To better define its antioxidant action, we investigated the effects of orally supplemented Bio-Normalizer on oxidative damage in the rat heart. Hearts were isolated from control or Bio-Normalizer supplemented animals and 1) exposed to ischemia-reperfusion using the Langendorff technique, or 2) homogenized and exposed to peroxyl radicals generated from (2,2'-azobis (2,4'-dimethylvaleronitrile) (AMVN). During reperfusion following 40 minutes of ischemia, leakage of lactate dehydrogenase from hearts isolated from Bio-Normalizer supplemented rats was significantly lower than from hearts of control animals. Furthermore, lower levels of AMVN-induced accumulation of thiobarbituric acid reactive substances and of protein carbonyl derivatives were measured in homogenates prepared from hearts isolated from Bio-Normalizer supplemented rats than in samples from control animals. Our findings confirm an antioxidant action of Bio-Normalizer and show that it protects the heart against ischemia-reperfusion induced damage.

Analysis of Variance↗
PubMed1996

[The level of alcohol and titre of A and B group substances of the ABO system in blood samples infected by some strains of Escherichia coli].

Evaluating the results of sectional blood examinations for ethyl alcohol content is difficult due to the proceeding putrid and fermentative processes, in consequence of which endogenic ethyl alcohol is produced. Some difficulties also arise from estimating the results of serological investigations concerning the biological traces having been changed by putrefaction, where the presence of heterogenic antigens may be suspected. The putrid-fermentative processes are linked with the activity of microorganisms, particularly bacteria and yeast-like fungi. The first part of the paper deals with the bacterial flora in 50 sectional blood samples taken for routine determinations of ethyl alcohol content, thus with added sodium fluoride as bacteriostatic agent. The identification of the microorganisms cultured on differentiating and selectively differentiating media was carried out on the basis of the culture appearance, specimens stained by Gram's method, as well as biochemical examinations. From 16 studied samples of the sectional blood no strain of bacteria was cultured, mixed bacterial flora was isolated from the remaining ones (Tab. 1). Most numerous were Gram-negative bacteria (71%) among which E.coli appeared most frequently. Gram-positive claimed 28% of the cultured microflora, while anaerobes hardly 4%. In the second part of the paper, the selected strains of E. coli pertaining to serological groups: 02, 04, 06, 08, 09, 022, 025 were studied with regard to their possibility to produce ethanol as well as antigens A and B of AB0 system. E.coli strains were grown on broth medium containing glucose in concentration of from 0.00 to 27.75 mmol/l and human blood of 0 group collected from blood-donors on sodium citrate and CPD preservative with glucose in its content. Ethanol concentration in cultures was determined after 24 and 72 hours of incubation, by gas chromatography method, and glucose by enzymatic method. In serological investigations the material consisted of linen pieces being covered with 72-hour cultures of E.coli on broth and human blood of group 0. The study for the presence of the group substances A and B of AB0 system was performed by absorption method according to Holzer, and by absorption and elution method. In consequence of the studies it has been ascertained that sodium fluoride added as a bacteriostatic agent does not entirely inhibit the growth of bacteria, and especially bacteria Gram-negative appeared to be least sensitive to its action (Tab. 1). Selected strains of E.coli have differed with regard to the efficiency of ethanol production (Tab. 2). The level of produced ethanol depended on glucose concentration in the medium, temperature and the incubation time (Tab. 2, 3, 4 and Fig. 1). Under almost similar conditions the same strains produce more alcohol than on blood, which may give rise to supposition that the blood modifies the metabolism of bacteria (Tab. 4 and 5). The cultures of selected strains studied failed to reveal the presence of heteroantigens with properties of antigen A and B of AB0 system.

ABO Blood-Group System↗
PubMed1989

Effect of FK973, a new antitumor antibiotic, on the cell cycle of L1210 cells in vitro.

Our previous study showed that FK973 (11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1,11- diazatetracyclo[7.4.1.0(2,7)0(10,12)]tetradeca-2,4,6-trien-6 ,9-diyl diacetate), a novel substituted dihydrobenzoxazine, which is a derivative of the fermentation product of Streptomyces sandaensis No. 6897, had strong antitumor effects on experimental tumors in vitro and in vivo. In this report, we investigated its effect on the cell cycle of murine leukemia L1210 cells in vitro by means of DNA/5-bromo-2'-deoxyuridine double staining and compared these effects with those of other antitumor drugs. Both FK973 and mitomycin C arrested the cells in the G2 phase. Vinblastine arrested the cells in the M phase and cytosine arabinoside, in the G1 phase. Although FK973 and mitomycin C were shown to act on the cell cycle in a similar way, FK973 was slower in producing its effect. From the results, FK973 arrests the cells in the G2 phase, and it appears that FK973 must be converted into the activated form in the cells for the development of its antitumor effects.

Animals↗
PubMed1988

Degradation of amino acids to short-chain fatty acids in humans. An in vitro study.

Short-chain fatty acids (SCFA) originate mainly in the colon through bacterial fermentation of polysaccharides. To test the hypothesis that SCFA may originate from polypeptides as well, the production of these acids from albumin and specific amino acids was examined in a faecal incubation system. Albumin was converted to all C2-C5-fatty acids, whereas amino acids generally were converted to specific SCFA, most often through the combination of a deamination and decarboxylation of the amino acids, although more complex processes also took place. This study indicates that a part of the intestinal SCFA may originate from polypeptides, which apparently are the major source of those SCFA (isobutyrate, valerate, and isovalerate) only found in small amounts in the healthy colon. Moreover, gastrointestinal disease resulting in increased proteinous material in the colon (exudation, mucosal desquamation, bleeding, and so forth) may hypothetically influence SCFA production.

Adult↗
PubMed1983

Role of DL-lactic acid as an intermediate in rumen metabolism of dairy cows.

The role of DL-lactic acid as an intermediate in the rumen of a Friesian X Holstein dairy cow adapted to a diet of hay ad libitum plus 12 kg of a concentrate mixture was studied in vitro and in vivo. Concentrations of soluble sugars in the rumen fluid became maximal at 30 min postfeeding, but at 90 min no sugars were detectable. The DL-lactate concentration increased very rapidly to about 30 mm at 30 min after feeding, whereas the maximum total VFA concentration was reached 15 min later. More than 80% of the DL-lactate fermented to VFA was converted by Megasphaera elsdenii. Whereas only 16% of L-lactate was fermented to propionate, 75% of the D-lactate was converted to propionic acid. When all soluble sugars had been fermented, the participation of M. elsdenii to lactate fermentation declined and fermentation patterns for D- and L-lactate became similar yielding mostly acetate. Except for a brief period immediately after feeding, DL-lactate did not appear to be an important precursor of VFA in the rumen of a cow adapted to concentrate feeding. DL-lactate may become a more important intermediate in rumen fermentation temporarily when dairy cows are gradually changed from a hay diet to a diet including concentrates. The first 30 d after parturition, when the changeover takes place, is an unstable period, during which the microbial population is changing to fit the new environment.

Animals↗
PubMed2002

An in vitro study of manure composition on the biochemical origins, composition, and accumulation of odorous compounds in cattle feedlots.

Very little is known about the biochemical origin of cattle feedlot odors and the environmental factors controlling their production. The tie between diet and manure composition is well established, but the effect of different manure compositions on odorous chemical production is unknown. This study describes the effect of starch, casein, and cellulose substrate additions to slurries of fresh (< 24 h) and aged cattle manure (> 1 d) on the anaerobic production of fermentation products and the consumption of substrates relative to no addition treatments. Aged cattle manure accumulated more VFA (245 to 290 mM) than the fresh manure (91 to 181 mM) irrespective of substrate additions (P < 0.001). In fresh manures, VFA concentrations were increased (P < 0.01) over no addition treatments when carbohydrate (starch or cellulose) was added, whereas starch and protein treatments to aged manure increased VFA content relative to no addition treatments (P < 0.001). Branched-chain VFA and aromatic compounds accumulated only in the aged manure (no addition and protein treatments), indicating that some protein fermentation occurred in those treatments. Based upon substrate loss, starch fermentation was the dominant process in both manures and all treatments with losses exceeding 18.6 g/L. Protein fermentation occurred only in the aged manure, specifically the no addition and protein treatments, when starch was no longer available. The production of odorous compounds from manure was controlled by substrate availability and pH, with pH related to lactate accumulation. We believe that calcareous soil and lactate-consuming microorganisms in the aged manure slurries minimized slurry acidification and resulted in greater accumulations of odorous products. Substrate additions had little effect on the overall accumulation of odor compounds in manure but had profound effects on odor compound composition. We propose that modifying cattle diets to limit starch and protein excretion would profoundly affect the production and accumulation of odor compounds in feedlots.

Animals↗
PubMed2004

Inhibition of ruminal microbial methane production by beta-cyclodextrin iodopropane, malate and their combination in vitro.

The objective of this study was to evaluate the effects of different concentrations of l-malate (0, 5, 10 and 20 mm), 2-iodopropane-beta-cyclodextrin complex (CD-IP) (0, 0.1, 0.2 and 0.4 mm) and a combination of malate (10 and 20 mm) plus CD-IP (0.2 and 0.4 mm) on methane production from corn starch. Ruminal fluid was collected from dairy cows, mixed with phosphate buffer (1 : 2) and incubated (30 ml) anaerobically at 38 degrees C for 6 h with or without additives. Fermentation of corn starch in the presence of malate resulted in an increase (p < 0.05) in pH of the medium, total volatile fatty acid (VFA), total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were unchanged. Methane production was decreased (p < 0.05) (15.5 to 20.4%). Addition of CD-IP in corn starch resulted in an increase (p < 0.05) in total VFA and molar proportion of propionate. Acetate, pH and ammonia-N concentration of the medium were decreased (p < 0.05). Total gas production was unchanged. Methane production was decreased (p < 0.05) (25.2 to 97.1%) and hydrogen production was increased (p < 0.05). Addition of l-malate to CD-IP resulted in an increase (p < 0.05) in total VFA, total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were decreased (p < 0.05). No effects were observed on medium pH. Methane production was decreased (p < 0.05) (49.5 to 97.1%). Hydrogen production was also decreased (p < 0.05) (54.5 to 64.1%) compared with those of CD-IP alone. Therefore, these additives may be used as supplements to inhibit methane production as well as to improve rumen fermentation and animal performance.

Animals↗
PubMed1998

Effect of specific growth rate on fermentative capacity of baker's yeast.

The specific growth rate is a key control parameter in the industrial production of baker's yeast. Nevertheless, quantitative data describing its effect on fermentative capacity are not available from the literature. In this study, the effect of the specific growth rate on the physiology and fermentative capacity of an industrial Saccharomyces cerevisiae strain in aerobic, glucose-limited chemostat cultures was investigated. At specific growth rates (dilution rates, D) below 0.28 h-1, glucose metabolism was fully respiratory. Above this dilution rate, respirofermentative metabolism set in, with ethanol production rates of up to 14 mmol of ethanol . g of biomass-1 . h-1 at D = 0.40 h-1. A substantial fermentative capacity (assayed offline as ethanol production rate under anaerobic conditions) was found in cultures in which no ethanol was detectable (D < 0.28 h-1). This fermentative capacity increased with increasing dilution rates, from 10.0 mmol of ethanol . g of dry yeast biomass-1 . h-1 at D = 0.025 h-1 to 20.5 mmol of ethanol . g of dry yeast biomass-1 . h-1 at D = 0.28 h-1. At even higher dilution rates, the fermentative capacity showed only a small further increase, up to 22.0 mmol of ethanol . g of dry yeast biomass-1 . h-1 at D = 0.40 h-1. The activities of all glycolytic enzymes, pyruvate decarboxylase, and alcohol dehydrogenase were determined in cell extracts. Only the in vitro activities of pyruvate decarboxylase and phosphofructokinase showed a clear positive correlation with fermentative capacity. These enzymes are interesting targets for overexpression in attempts to improve the fermentative capacity of aerobic cultures grown at low specific growth rates.

Acetates↗
PubMed2005

Tumor necrosis factor alpha reduces butyrate oxidation in vitro in human colonic mucosa: a link from inflammatory process to mucosal damage?

BACKGROUND: Butyrate produced by colonic bacterial fermentation is the main fuel for colonocytes, glucose being an alternative fuel. During inflammatory bowel disease, butyrate oxidation by colonocytes is impaired, and increased production of proinflammatory cytokines is detected in the colonic mucosa. We hypothesized that proinflammatory cytokines might reduce butyrate oxidation, and we assessed the in vitro effects of 3 proinflammatory cytokines on butyrate and glucose oxidation in colonic mucosa. METHODS: Colonic biopsies were obtained from normal mucosa in 42 patients who underwent a colonoscopy. Biopsies were incubated in RPMI 1640 with [1-14C]-butyrate or [U-14C]-glucose with or without 1 of the 3 following proinflammatory cytokines: tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta, and IL-6. For each cytokine, 4 different concentrations were tested in 8 subjects. Concentrations overlapped those commonly found in inflamed mucosa and had no cytotoxicity as assessed in preliminary experiments using both the trypan blue exclusion test and lactate dehydrogenase release. Production of 14CO2 (picomoles per microgram dry weight per hour) was measured after a 2-hour incubation and expressed as a percentage of the control [14C]-substrate oxidation without cytokines. RESULTS: Whereas glucose oxidation was not affected, butyrate oxidation was reduced significantly (P < 0.05) by TNFalpha at concentrations of 100 (-26 +/- 6%), 1000 (-32 +/- 7%), and 5000 pg/mL (-34 +/- 5%). IL-1beta (0, 500, 5000, and 25,000 pg/mL) and IL-6 (0, 100, 1000, and 5000 pg/mL) did not affect either substrate oxidation. CONCLUSIONS: TNFalpha at concentrations found in inflamed mucosa reduces butyrate oxidation in vitro in mucosa from healthy controls. This result is not caused by a cytotoxic effect of TNFalpha and is not balanced by an increased oxidation of glucose. Reduced butyrate oxidation results in a decreased energy supply to colonocytes and may explain, in part, mucosal damage occurring during attacks of inflammatory bowel disease.

Aged↗