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PubMed2006

Rapid determination of short-chain fatty acids in colonic contents and faeces of humans and rats by acidified water-extraction and direct-injection gas chromatography.

Short-chain fatty acids (SCFAs) have attracted much attention recently because of their positive physiological effects. In this work, a rapid and reliable gas chromatographic method for determination of eight SCFAs, in colonic and faecal samples from rats and humans has been developed and validated. The methodology involves extraction of the SCFAs in water before a direct injection procedure on a FFAP capillary column. A stock standard solution containing acetic acid, propionic acid, n-butyric acid, i-butyric acid, n-valeric acid, i-valeric acid, n-caproic acid and n-heptanoic acid was prepared and used. A high linearity (r2 > 0.9990), low quantification limit (2.38-30.14 microm) and high recovery for most acids were obtained. Acidification of faecal samples was found to be crucial for quantitative determination of the SCFAs, and adjustment of pH to 2-3 was regarded as necessary. Glass wool inserted in the glass liner of the injection port proved effective in preventing the contamination of the column by non-volatiles, and 12% formic acid reduced the ghost peak that appeared gradually after several injections. After validation, the methodology was applied on two faecal samples from rats fed diets containing different amount of dietary fibre and one faecal sample from human fed a normal diet to test the accuracy of the developed method.

Adult↗

PubMed2006

Determination of short-chain fatty acids in serum by hollow fiber supported liquid membrane extraction coupled with gas chromatography.

A method based on hollow fiber supported liquid membrane extraction coupled with a gas chromatograph equipped with flame ionization detector (GC-FID) was developed for the determination of six short-chain fatty acids including acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid and n-valeric acid in serum. Hollow fiber supported liquid membrane extraction was employed for preconcentration and clean-up of the samples. The fatty acids were extracted from the acidic donor (diluted serum) into a liquid membrane formed in the wall of the hollow fiber with 10% tri-n-octylphoshphine oxide (TOPO) in di-n-hexyl ether, and then extracted back into a basic acceptor solution filled in the lumen of the hollow fiber. After being acidified with HCl, the acceptor was directly analyzed by GC-FID. The acceptor concentration, donor pH, membrane liquid and extracting time were optimized giving an enrichment factor up to 155 times. The good linearity (r(2)>0.980), reasonable recovery (87.2-121%), and satisfactory intra-assay (8.2-11.5%) and inter-assay (6.1-11.6%) precision illustrated the good performance of the present method. Limits of detection (LOD) ranged from 0.04 to 0.24 microM and limits of quantification (LOQ) varied from 0.13 to 0.80 microM.

Chromatography, Gas↗

PubMed1994

The effect of condensed tannins in Lotus corniculatus on plasma metabolism of methionine, cystine and inorganic sulphate by sheep.

Fresh Lotus corniculatus containing 27 g extractable condensed tannin (CT)/kg dry matter (DM) and 8 g bound CT/kg DM was fed at hourly intervals to sheep held in metabolism cages to study the effects of CT on nutrient digestion and on metabolism of methionine, cystine and inorganic sulphate in plasma. Polyethylene glycol (PEG) was continuously infused into the rumen of half the sheep to remove the effects of CT. Principal measurements in the two groups were plasma irreversible loss (IRL) rate and interconversions of methionine, cystine and inorganic sulphate using 35S labelling. CT in Lotus corniculatus had no effects on the apparent digestion of cellulose and minerals, slightly depressed DM, organic matter and hemicellulose digestion and markedly reduced the apparent digestion of N (P < 0.01). The concentration of NH3 and molar proportions of iso-butyric acid, iso-valeric acid and n-valeric acid in rumen fluid were markedly increased by the PEG infusion (P < 0.01), whereas total volatile fatty acid concentration and molar proportions of acetic acid, propionic acid and n-butyric acid were not affected. PEG infusion temporarily increased rumen protozoa numbers. CT greatly increased the IRL of plasma cystine (13.1 v. 7.0 mumol/min; P < 0.05) and reduced IRL of plasma inorganic sulphate (36.8 v. 48.1 mumol/min; P < 0.01) but had no effect on methionine IRL. CT increased transulphuration of methionine to cystine (4.37 v. 1.24 mumol/min; P < 0.05), increased cystine entering the plasma from whole-body protein turnover plus absorption from the small intestine (9.34 v. 5.75 mumol/min; P < 0.05) and increased cystine flux to body synthetic reactions (11.89 v. 5.41 mumol/min; P < 0.05). CT had no effect on the proportion of methionine total flux transferred to sulphate (0.05 v. 0.06; P < 0.05), reduced the proportion of methionine flux transferred to body synthetic reactions (0.68 v. 0.86) and markedly reduced the proportion of cystine flux transferred to sulphate (0.09 v. 0.27; P < 0.01). It was concluded that CT in Lotus corniculatus reduced rumen protein degradation and markedly increased utilization of plasma cystine for body synthetic reactions.

Animal Feed↗

PubMed1993

Characterization of trace amounts of odorants (sulfur compounds, oxygenates, hydrocarbons, phenols and lower fatty acids) in air in an ICU room.

Characterization of trace amounts of odorants in air in an ICU room (ca.257m2) was carried out by gas chromatography and atmospheric pressure ionization-mass spectrometry (API-MS). The concentrations and odor recognition threshold values of the detected odorants, acetaldehyde, ethanol, n-butyric acid, iso-valeric acid and n-valeric acid are as follows: 44.7 ppb and 15 ppb; 19710 ppb and 6100 ppb; 0.50 ppb and 0.4 ppb; 0.45 ppb and 0.4 ppb; 0.67 ppb and 0.5 ppb, respectively. The detected concentrations of these odorants were significantly higher than the odor recognition threshold values. The compounds may, therefore, be responsible for perception of such odors as mixed odors, body odor, and faint or recognizable alcoholic odor, disinfectant odor, and sour, pungent, and goat odors.

Chromatography, Gas↗

PubMed2004

Isolation of Lactobacillus sakei strain KJ-2008 and its removal of characteristic malodorous gases under anaerobic culture conditions.

A number of different sources, such as composts, leachates, and pig feces samples were collected from different pig farms in Korea. Several microorganisms were screened for their ability to deodorize the malodorous gases. As a result, a novel malodorous gas-deodorizing bacterial strain KJ-2008 was isolated due to the most abundant of nitrate-supplemented minimal media under anaerobic conditions. Crimp-sealed serum bottles containing nitrate-supplemented minimal medium (MM-NO(3)(-)) in airtight conditions were inoculated with KJ-2008. Nitrate concentration decreased rapidly after 20 h incubation and nitrite production reached almost zero during the time the experimental was carried out. Taxonomic identification including 16S rDNA base sequencing and phylogenetic analysis indicated that the isolate KJ-2008 had a 99.8% homology in its 16S rDNA base sequence with Lactobacillus sakei. Among the volatile fatty acids, acetic acid contained in large amounts in fresh piggery slurry decreased about 40% after 50 h incubation of the strain KJ-2008. n-Butyric acid, n-valeric acid, and iso-valeric acid gradually decreased, and iso-butyric acid and capronic acid dramatically eliminated at initial time with the treatment. Moreover, NH(3) removal efficiency reached a maximum of 98.5% after 50 h of incubation. The concentration of H(2)S did not change.

Anaerobiosis↗

PubMed2000

Development of an attractant for the scarab pest Macrodactylus subspinosus (Coleoptera: Scarabaeidae).

Field trials were conducted over several seasons to determine the attractant most successful in luring adult rose chafers, Macrodactylus subspinosus (F.), to traps. During the first season, 20 compounds were compared with the standard lure, valeric acid + hexanoic acid + octyl butyrate (1:1:1). The two new standards establishedthat season were: valeric acid + 1-nonanol (1:1); and valeric acid + hexanoic acid + octyl butyrate + 1-nonanol (1:1:1:1). The following season, 36 compounds were evaluated, comparing them to the new standards. The performance of the standard binary lure valeric acid + 1-nonanol was improved when the alcohol 1-nonanol was replaced by its analog trans-2-nonenol and this was confirmed during the third season. At the same time, a second test was conducted with 29 new candidates, which were combined with valeric acid and compared with the standard: valeric acid + hexanoic acid + octyl butyrate + 1-nonanol (1:1:1:1). A control and the single compound alpha-ionone were included, resulting in the discovery of a new more powerful attractant, alpha-ionone. Testing of alpha-ionone continued the following season, at which time the initial leading candidate and new ones containing trans-2-nonenol were tested against the single attractant alpha-ionone and various combinations of it. A new five-component mixture of valeric acid, hexanoic acid, octyl butyrate, trans-2-nonenol, and alpha-ionone out performed all other lure combinations.

Animals↗

PubMed1976

The encephalopathic action of five-carbon-atom fatty acids in the rabbit.

1. Five-carbon-atom organic acids (C-5 acids) have been administered intravenously to rabbits with ventriculocisternal perfusion and continuous electroencephalographic recording (EEG). The concentration of the acids in the cerebrospinal fluid (CSF) perfusate have been compared with changes in integrated low-frequency activity in the EEG. 2. The C-5 acids investigated were those accumulating in inborn errors of metabolism, i.e. isovaleric acid, beta-methylcrotonic acid, tiglic acid and alpha-keto- and alpha-hydroxy-isovaleric acid. There activity was compared with that of valeric acid. 3. Valeric acid and isovaleric acid produced coma and pronounced increase in slow-wave electrical activity and these changes paralleled the increase in concentration of the acids in the CSF perfusate. 4. The concentration of beta-methylcrotonic acid and tiglic acid in the CSF perfusate reached values comparable with valeric acid and isovaleric acid but showed less encephalopathic activity. An interaction between beta-methylcrotonic acid and isovaleric acid was observed. 5. Although the concentrations of alpha-ketoisovaleric acid and alpha-hydroxyisovaleric acid rose to the lesser extent in the CSF perfusate, changes in rousability of the animal and in the EEG recording were demonstrated. 6. It is concluded that all the C-5 acids tested have encephalopathic activity although this is lessened by the presence of either a double bond or an oxygenated functional group.

Animals↗

PubMed1995

Relationships between microflora and caecal fermentation in rabbits before and after weaning.

Some microbiological and biochemical parameters of caecal content were studied in 15- to 49-d-old rabbits that were slaughtered sequentially. The ammonia level did not differ before weaning (11.5 mmol/L on average) (P = 0.41) or after weaning (7.4 mmol/L on average) (P = 0.19) but decreased by 40% (P < 0.001) between days 29 and 32. The level of pH decreased linearly (P < 0.001) throughout the period studied. The Escherichia coli counts decreased up to weaning (P < 0.001) and was then not significantly affected by age (P = 0.12). The total volatile fatty acid (VFA) concentration increased between days 15 (8.2 mmol/L) and 25 (33.9 mmol/L) (P < 0.05) and then levelled off below 40 mmol/L. Molar proportions in propionate and in branched-chain fatty acid (BCFA) and valeric acid were high at day 15 but decreased when the animals began to eat solid feed. The C3/C4 ratio reversed at weaning (3.8 on day 15 and 0.5 on day 49) whereas the acetic acid proportion was not affected by age (P = 0.19). High counts of anaerobic microflora were found between 15 and 22 d of age (10(11) bacteria/g of caecal content, on average) and did not change significantly according to the age (at about 10(10) bacteria/g), from day 29 until the end of the experiment (P = 0.29). Amylolytic flora had a similar evolution at a slightly lower level. In contrast, under our breeding conditions cellulolytic microflora slowly colonized the caecum and remained at a low level. The discriminant analysis revealed relationships between ages, intestinal microflora and fermentation parameter; the colibacilli flora was associated with mother-fed animals and amylolytic flora which was linked to BCFA and valeric acid, while the cellulolytic flora was associated with animals older than 4 weeks and linked to the production of C2, C3, C4 and ammonia.

Aging↗

PubMed1975

Metabolism of liquid whey fed to sheep.

Digestion was studied with three groups of four sheep each fed alfalfa hay. Treatments were whey only, whey plus water, and water only. Digestibilities of dry matter for the three rations were 71.3, 69.7, and 62.9%. Digestibilities of whey solids calculated by difference was 86.9% for whey only and 81.6% for whey plus water. Twelve sheep were in three trials to determine the intake of whey, water, and hay consumption. They were assigned to whey only, whey plus water, and water only. Hay, whey, and water consumption was 1.89, 8.73, and 0; 1.88, 7.62, and 1.21; and 2.05, 0, and 6.07 kg per animal daily. Three mature fistulated wether sheep were fed 6 liters of liquid whey daily. Three mature fistulated wether sheep uere fed 6 liters of liquid whey daily, and three similar sheep were fed water only. Rumen liquor samples were taken for analysis of volatile fatty acids at 0, 3, and 6 h after whey feeding on each of three alternate days. Alfalfa hay (1.2 kg/animal daily) was fed after the 6-h sampling. Molar percentage of acetic and valeric acids were lower and for butyric acid was higher for sheep fed whey. Propionic acid, acetate:propionate ratio, and total concentration were not affected significantly by whey feeding. Acetic acid decreased from 0 to 3 h, then partly returned to the prefeeding level at 6 h. The reverse was true for butyric acid. Valeric acid and total concentration of volatile fatty acids decreased from 0 to 6 h. Effects of day were unexplained.

Animal Feed↗

PubMed1982

Immunosuppressive properties of polar organic compounds that induce cellular differentiation in Friend erythroleukemia cells.

We studied the effect of several polar organic compounds, known to induce erythroid differentiation in Friend leukemia (FL) cells, on in vitro human lymphocyte responses and on skin graft survival in mice. The short chain fatty acids, butyric acid (BA), propionic acid (PA), valeric acid, and the polar organic solvents, dimethyl sulfoxide, dimethylformamide, and dimethylacetamide, all mediated significant inhibition of alloantigen-induced proliferation and generation of cytotoxic T lymphocytes (CTLs) in human primary and secondary mixed lymphocyte culture (MLC) reactions. Hexamethylenebisacetemide, another potent inducer of differentiation in FL cells, also mediated significant suppression. Inhibition of MLC with polar organic compounds was accomplished at concentrations known to induce differentiation in FL cells and that are not cytotoxic to peripheral blood mononuclear cells. In distinct contrast, agents that are structurally related to BA, but that do not induce differentiation in FL cells, such as caproic acid, beta-OHBA, gamma-amino BA, and isobutyric acid, did not exhibit immunosuppressive properties. Pokeweed mitogen-driven polyclonal B cell activation was also suppressed by agents that induce erythroid differentiation in FL cells. In addition to potent in vitro immunosuppressive properties, supplementation of drinking water with BA or PA resulted in prolongation of full-thickness skin grafts in DBA/2 (H-2d) to C57BL/6 (H-2b) donor-recipient combinations. Our findings indicate that polar organic compounds that induce differentiation in FL cells are potent immunosuppressive agents.

3-Hydroxybutyric Acid↗

PubMedDate not supplied

Production of poly(3-hydroxybutyrate) and its copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Erwinia sp. USMI-20.

A locally isolated soil microorganism identified as Erwinia sp. USMI-20 has been found to produce poly(3-hydroxybutyrate), P(3HB), from either palm oil or glucose and its copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), from a combination of palm oil and a second carbon source of either one of the following compounds: propionic acid, n-propanol, valeric acid and n-pentanol. It was found that Erwinia sp. USMI-20 could produce P(3HB) up to 69 wt.% polymer content with a dry cell weight of 4.4 g/l from an initial amount of 14.5 g/l of glucose followed by a feeding rate of glucose at 0.48 g/h glucose. On the other hand, the bacteria can achieve 46 wt.% of P(3HB) and a dry cell weight of 3.6 g/l from a batch fermentation in a 10-l fermentor from an initial concentration of 4.6 g/l of palm oil. Further characterisation of the polymer production was also carried out by using different types of palm oil. Among the different palm oils that were used, crude palm oil was the best lipid source for P(3HB) production as compared to palm olein and palm kernel oil. In the production of the copolymer, P(3HB-co-3HV), the highest mole fraction of 3-HV units could be as high as 47 mol% from a single feeding of valeric acid upon initial growth on palm oil.

Culture Media↗

PubMed1979

Propionyl-CoA carboxylase deficiency with overflow of metabolites of isoleucine catabolism at all levels.

An 11-year old girl with spastic paraplegia and mental retardation has suffered from attacks of metabolic acidosis since the age of 18 months. "Ketotic hyperglycinemia" was diagnosed when she was 3 years old. Reinvestigation at 9 1/2 years included a two-day load with L-isoleucine, and propionyl-CoA carboxylase assay in cultured fibroblasts. The following compounds increased following the load: 3-hydroxypropionic acid, 2-methyl-3-hydroxybutyric acid, 2-ethylhydracrylic acid, 3-hydroxy-n-valeric acid, 3-oxo-n-valeric acid, 2-methyl-3-oxobutyric acid, 2-oxo-3-methylvaleric acid, 2-methyl-3-oxovaleric acid, N-tiglylglycine, methylcitric acid and butanone. Small amounts of alloisoleucine appeared in plasma. Propionyl-CoA carboxylase deficiency was suggested by this metabolite pattern and demonstrated in cultured fibroblasts.

Acidosis↗

PubMed1990

Biosynthesis and composition of bacterial poly(hydroxyalkanoates).

It is well established that Alcaligenes eutrophus can accumulate a copolymer containing 3-hydroxybutyrate and 3-hydroxyvalerate, but longer 3-hydroxyacid monomers have not been reported to occur in this organism. The properties of the enzymes of poly(hydroxyalkanoate) (PHA) biosynthesis are discussed and it is proposed that the substrate specificity of the polymerizing enzyme restricts the range of monomer units incorporated into PHA. Various other bacteria produce similar copolymers from propionic acid and/or valeric acid. A number of Pseudomonas species accumulate PHAs containing longer-chain monomer units from linear alkanoic acids, alkanes and alcohols.

Alcaligenes↗

PubMed2003

H2 production with anaerobic sludge using activated-carbon supported packed-bed bioreactors.

Packed-bed bioreactors containing activated carbon as support carrier were used to produce H2 anaerobically from a sucrose-limiting medium while acclimated sewage sludge was used as the H2 producer. The effects of bed porosity (epsilon(b)) and substrate loading rate on H2 fermentation were examined using packed beds with epsilon(b) of 70-90% being operated at hydraulic retention times (HRT) of 0.5-4 h. Higher epsilon(b) and lower HRT favored H2 production. With 20 g COD l(-1) of sucrose in the feed, the optimal H2 production rate (7.4 l h(-1) l(-1)) was obtained when the bed with epsilon(b) = 90% was operated at HRT = 0.5 h. Flocculation of cells enhanced the retention of sludge for stable operations of the bioreactor at low HRTs. The gas products resulting from fermentative H2 production consisted of 30-40% H2 and 60-70% CO2. Butyric acid was the primary soluble product, followed by propionic acid and valeric acid.

Bacteria, Anaerobic↗

PubMedDate not supplied

Caecal microflora and fermentation pattern in exclusively milk-fed young rabbits.

Thirty-two SPF New Zealand White rabbits of both sexes were used in this experiment. They were sequentially slaughtered at 22, 29, 35 and 42 days of age. The rabbits were only milked by their mother and by foster mothers (no access to solid food) throughout the experiment. They exhibited a caecal fermentation pattern that turned towards a proteolytic metabolic activity (high levels in NH3 and in branched-chain fatty acids and valeric acid: 17 mmol.L-1 and 1 mmol.L-1, on average, respectively). The absence of caecal cellulolytic microflora and the low concentration of the total volatile fatty acids (tVFA) could be explained by the lack of substrate that would have been brought by a solid feed. From day 29 onwards, the low tVFA (12.5 mmol.L-1) and high NH3 concentrations (16.5 mmol.L-1) explained the high pH value (6.8 on average). This could be considered as a pathological value in weaned rabbits, but in our case no clinical signs of diarrhoea were observed. The evolution of the colibacilli flora according to age was similar to that usually described and thus was not correlated with pH, tVFA or cellulolytic flora. The evolution of the colibacilli population (from 10(7) bact/g on day 22 to 10(3) on day 42) seemed dependent on ontogenic factors rather than on the composition of the caecal media (pH, etc.).

Aging↗

PubMed2005

Transport of prostaglandin E1 across the blood-brain barrier in rats.

The transport of prostaglandin E(1) (PGE(1)) across the blood-brain barrier (BBB) was characterized using an in-situ rat brain perfusion technique. The uptake of [(3)H]PGE(1) was not affected by shortchain monocarboxylic acids (butyric acid and valeric acid). On the other hand, uptake of [(3)H]PGE(1) was significantly inhibited by medium-chain monocarboxylic acids such as hexanoic acid, enanthic acid and octanoic acid. These medium-chain monocarboxylic acids showed a more potent inhibitory effect on [(3)H]PGE(1) uptake with increasing number of carbon atoms. In contrast, there was no decrease in [(3)H]PGE(1) transport by any dicarboxylic acids with 5-8 carbon atoms. Valproic acid decreased [(3)H]PGE(1) uptake, whereas p-aminohippuric acid, a substrate for the organic anion transporter family, did not inhibit [(3)H]PGE(1) transport. Bromocresol green, an inhibitor of prostaglandin transporter (PGT), strongly decreased [(3)H]PGE(1) transport across the BBB. In addition, digoxin and taurocholate, substrates for organic anion transporting polypeptide subtype 2 (Oatp2), significantly inhibited [(3)H]PGE(1) uptake. RT-PCR analysis revealed that PGT mRNA and Oatp2 mRNA are expressed in a capillary-rich fraction from rat brain. Thus, it is suggested that PGE(1) transport across the BBB is mediated by some specific transport systems, possibly by the members of the Oatp family.

Alkaline Phosphatase↗

PubMed1993

Pharmacokinetic analysis of phenytoin and its derivatives in plasma and brain in rats.

The derivatives of phenytoin (DPH) were synthesized by the reaction at 3 position of hydantoin ring with valproic acid and valeric acid, producing valproyl DPH (VPDPH) and valeroyl DPH (VADPH), respectively. These derivatives showed much higher lipid solubilities than that of DPH. Their distribution and elimination were compared to those of DPH. Additionally, the concentration profiles of the drugs in brain and plasma were analyzed with a modified 2-compartment model. DPH and its derivatives, without hydrolysis to DPH in blood, were found rapidly distributed into brain, although the distribution of derivatives was much less, probably due to the high protein binding capacities. The distribution of DPH and its derivatives into brain regions was similar to that into the cortex cerebri. VPDPH and VADPH were more rapidly eliminated from plasma and brain than DPH, giving smaller mean residence time (MRT) values (0.92 and 0.85 h) and much smaller cortex/plasma concentration ratio than those of DPH. The VPDPH and VADPH concentrations in the cerebrospinal fluid (CSF) were also much lower than that of DPH. The time course of plasma and brain concentrations of DPH and its derivatives after i.v. administration was successfully described by the modified 2-compartment models presented.

Animals↗

PubMed1993

Effects of transgalactosylated disaccharides on the human intestinal microflora and their metabolism.

The effects of transgalactosylated disaccharide (TD) intake on human fecal microflora and their metabolism were investigated in 12 Japanese males. TD is a mixture of sugars, galactosyl galactose, and galactosyl glucose, synthesized from lactose through the transgalactosylation reaction of Streptococcus thermophilus beta-galactosidase. Volunteers took 15 g of the test sugar daily for 6 days. The TD ingestion increased the number of bifidobacteria and lactobacilli, but decreased the number of Bacteroidaceae and Candida spp. in the feces. The ratio of bifidobacteria to total bacteria increased from 0.28 to 0.51. TD decreased the fecal concentrations of propionic acid, isobutyric acid, isovaleric acid, and valeric acid. This sugar also lowered the fecal pH, and the concentrations of fecal ammonia, p-cresol, and indole. Moreover, a positive correlation was found between the concentration of ammonia, and that of branched-chain fatty acids (isobutyric acid and isovaleric acid), p-cresol, and indole. All of these compounds are produced from amino acids through deamination by the intestinal bacteria. The depression of amino acid fermentation by intestinal bacteria may be involved in the reduction of fecal ammonia. These results suggest that a part of the transgalactosylated disaccharides passes into the colon, inducing changes in the colonic microflora composition, hastening carbohydrate fermentation, and depressing amino acid fermentation in the human gut.

Adult↗