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PubMed2004

Anaerobic degradability of alcohol ethoxylates and related non-ionic surfactants.

The anaerobic degradability of alcohol ethoxylates with various degrees of branching and several related substances was studied. Different inocula were employed in order to increase the probability of obtaining capable bacteria, and the degradation assays were fed with several small doses of the test substances in order to avoid inhibition by too high initial concentrations. Mineralization was quantified by monitoring the biogas production and inorganic carbon concentration in the liquid phase. Almost complete mineralization was achieved in the assays with linear alcohol ethoxylate, poly(ethylene glycol), dodecanol, 2-ethyl-hexanoic acid and 3-methyl-valeric acid. No significant degradation was detected in the assays with highly branched alcohol ethoxylate, 2-butyl-branched alcohol ethoxylate, alcohol alkoxylate, poly(propylene glycol) and iso-tridecanol. A 2-ethyl-branched alcohol ethoxylate was transformed to (2-ethyl-hexyloxy)-acetate, which was not further degraded. Apparently already the first step of anaerobic degradation of alcohol ethoxylates, the ethoxylate chain shortening, is sterically hindered by the alkyl branching. Alkyl branching in alcohol ethoxylates and the inclusion of propylene oxide units in alcohol alkoxylates seem to have a clearly more detrimental effect on anaerobic degradability than on aerobic degradability.

Alcohols↗

PubMed1996

Conversion of L-lactate oxidase to a long chain alpha-hydroxyacid oxidase by site-directed mutagenesis of alanine 95 to glycine.

A mutant form of L-lactate oxidase (LOX) from Aerococcus viridans in which alanine 95 was replaced by glycine was constructed as a mimic of L-lactate monooxygenase but proved instead to be a mimic of the long chain alpha-hydroxyacid oxidase from rat kidney. A95G-LOX keeps oxidase activity with L-lactate at the same level as wild type LOX but has much enhanced oxidase activity with longer chain L-alpha-hydroxyacids, alpha-hydroxy-n-butyric acid, alpha-hydroxy-n-valeric acid, etc., and also the aromatic alpha-hydroxyacid, L-mandelic acid. Kinetic analysis of the activity with these substrates indicates that the reduction of the enzyme bound flavin by substrates is the rate-limiting step in A95G-LOX. The affinity of pyruvate for the reduced enzyme is increased, and sulfite binding to the oxidized enzyme is weaker in A95G-LOX than in native enzyme. Wild type LOX stabilizes both the neutral and anionic flavin semiquinones with a pKa of 6.1, but A95G LOX stabilizes only the anionic semiquinone form. These results strongly suggest that the environment around the N5-C4a region of the flavin isoalloxazine ring is changed by this mutation.

Alanine↗

PubMed1994

Butyrate enhances the in vitro anti-SRBC (sheep red blood cell) antibody responses in murine splenocytes.

Butyrate at concentrations of 200-600 microM markedly enhanced the in vitro antibody productions against sheep red blood cells (SRBC) in murine splenocytes. However, other saturated short-chain fatty acids, including acetate, propionate and valeric acid, and 4-carbon compounds such as butanol, acetoacetate and beta- and gamma-hydroxybutyrate had no such effects. The presence of butyrate in the early phase of the cell culture was crucial for enhancement of the response. Butyrate also augmented the antibody production in T-cell-depleted splenocytes supplemented with the culture supernatant of concanavalin A (Con A)-stimulated lymphocytes. Interleukin (IL)-2 secreted from splenocytes in response to SRBC was increased by adding butyrate to the culture, but IL-1 secretion was not affected. On the other hand, Con A or lipopolysaccharide-stimulated proliferation of splenocytes was partly depressed by the addition of butyrate, while Con A-induced IL-2 production was not effected. These findings suggest that butyrate may act on T and B cells to promote their differentiation during the process of antibody production.

Animals↗

PubMed1993

Sequencing analysis of mutation points in the biotin operon of biotin-overproducing Escherichia coli mutants.

We analyzed mutation points of the biotin operon from biotin-overproducing mutants of Escherichia coli resistant to two biotin analogs, actithiazic acid and 5-(2-thienyl)-valeric acid, by DNA sequencing. The biotin operons cloned from these mutants were classified into three groups. One point mutation, which was a GC-->AT change within the operator overlapping the -10 region of the rightward (bioB) promoter, was considered to result in disruption of operator structure and enhancement of promoter activity. Two other point mutations, which were both GC-->AT changes just before and after the initiation codon of the bioB gene, were considered to activate the translation efficiency. These mutations significantly accelerated the biotin-forming activity from dethiobiotin in cell-free extracts.

Base Sequence↗

PubMed1985

[Measurement of the appearance of volatile fatty acids in the portal vein during digestion in conscious pigs].

A method used to measure the nutrient exchanges between the intestinal lumen and the portal blood was applied to 3 pigs receiving 800 g of a diet containing 6% of cellulose. During a postprandial period of 24 hrs., the mixture of volatile fatty acids (90 mM/h) appearing in the portal vein was composed of acetic acid (57%), propionic acid (30%), butyric acid (9%), isovaleric (2.5%) and valeric acid (1.5%). The composition of this mixture differed from that of the colic contents because of its acetic acid enrichment at the expense of butyric acid. The resulting energy supply to the animal represented about 600 to 700 kcal/24 hrs.

Animals↗

PubMed1984

Stimulation of phosphate transport in the proximal tubule by metabolic substrates.

Studies of phosphate transport in the proximal tubule have recently focused on interactions with cellular metabolism. The present studies demonstrate that two fatty acids, valerate and butyrate, and two tricarboxylic acid cycle intermediates, succinate and malate, stimulate net phosphate transport in the rabbit proximal tubule by 34-117%. Valerate had no effect on the total uptake of inorganic [32P]phosphate into suspensions of proximal tubules but did enhance the initial rate of influx. Net fluid transport was unaffected by these substrates although glucose absorption increased by 10-15% following the addition of either valerate or succinate. Since valerate, butyrate, and succinate are known to stimulate gluconeogenesis and respiration, we evaluated the role of gluconeogenesis in the stimulation of phosphate transport. The addition of 3-mercaptopicolinate (1 mM), an inhibitor of gluconeogenesis, did not alter phosphate transport, nor did it prevent the valerate-induced stimulation of phosphate transport. We conclude that valerate, butyrate, succinate, and malate enhance phosphate transport by the proximal convoluted tubule. This action appears to be unrelated to effects on gluconeogenesis and may be related to close links between phosphate transport and oxidative metabolism.

Animals↗

PubMed1980

Uptake of piperidine and pipecolic acid by synaptosomes from mouse brain.

Piperidine is actively transported into the synaptosomal fraction of adult mouse brain. The transport mechanism appears to be Na+ independent but is temperature dependent and sensitive to ouabain. Analysis of kinetic experiments indicates only a "low-affinity" transport system to be present. By contrast the uptake of D,L-[(3)H]pipecolic acid at a concentration of 4 X 10(-7)M was temperature and Na+ dependent, ouabain sensitive, and revealed a two-component system with a Km = 3.9 plus or minus 0.17 X 10(-6)M, Vmax = 129 plus or minus 6 pmol/mg protein/3 min for the "high-affinity" system and a Km = 90.2 plus or minus 4.3 X 10 (-6)M, Vmax = 2.45 plus or minus 0.19 nmol/mg protein/3 min for the "low-affinity" system. Compounds structurally related to pipecolic acid such as glycine, L-proline, 4-amino-n-butyric acid, and 5-amino-n-valeric acid showed an inhibitory effect on uptake at a concentration of 10(-4)M. The demonstration of biosynthesis of pipecolic acid in mouse brain and the presence of a "high-affinity" sodium-dependent uptake system suggest a physiological role of this substance in the central nervous system.

Animals↗

PubMed2003

Branched chain amino acids as source of specific branched chain volatile fatty acids during the fermentation process of fish sauce.

The source of the formation of branched chain volatile fatty acids (VFA) in fish sauce was investigated. Certain branched VFA were derived from the degradation of specific amino acids as iso-butyric acid from valine and iso-valeric acid from leucine. Short and long straight chain VFA were significantly higher in the linoleic acid added sample than in the control but did not significantly bring changes to the branched chain VFA. It is suggested that straight chain VFA developed from fish fats. Alanine and isoleucine did not have a clear influence on the production of volatile fatty acids.

Amino Acids, Branched-Chain↗

PubMed2006

Metabolic phenotyping of nude and normal (Alpk:ApfCD, C57BL10J) mice.

Mice provide a range of important models of human disease. As part of a broad program of metabolic phenotyping (metabotyping) the effects of gender and strain upon urinary metabolite composition and variation have been investigated using 1H NMR spectroscopy and chemometrics in the Alpk:ApfCD, C57BL10J and the "Nude mouse". By using Principal Components Analysis (PCA) and Soft Independent Modeling by Class Analogy (SIMCA), characteristic metabotypes for each strain were produced for both male and female animals. In all three strains, female urinary metabolic profiles were characterized by higher lactate, trimethylamine-N-oxide and lower trimethylamine concentrations relative to males. Both male and female Nude mice were phenotypically distinct from the Alpk:ApfCD and C57BL10J strains-the Nude mouse phenotypes being characterized by higher urinary creatinine, guanadinoacetic acid, dimethylamine, alpha-hydroxy-N-valeric acid and taurine levels and lower hippurate, citrate, creatine and succinate concentrations relative to those excreted by the two phenotypically normal mouse strains. These data show that Nude mice exhibit a wide variety of metabolic differences across a much wider range of pathways than has previously been thought, with potentially important considerations for studies that use the Nude mouse as a mouse model.

Alanine↗

PubMed1985

Cytotoxic effects of culture supernatants of oral bacteria and various organic acids on Vero cells.

Dilute culture filtrates of the three asaccharolytic black-pigmented Bacteroides species as well as B. macacae, Fusobacterium nucleatum, and animal strains resembling B. gingivalis were cytotoxic for the African green monkey kidney cell line (Vero cells). Butyric or propionic acid, major metabolic products of these bacteria, seem to be responsible for the characteristic morphological changes observed. Among the organic acids studied, only butyric, propionic, and valeric acids exhibited cytotoxic effects. Finally, cumulative effects (as opposed to synergistic) were observed when mixtures of two organic acids were tested.

Animals↗

PubMed2005

Specificity of the fluorescein transport process in Malpighian tubules of the cricket Acheta domesticus.

We demonstrate the presence of an efficient, multispecific transport system for excretion of organic anions in the Malpighian tubules of the cricket Acheta domesticus using fluorescein (FL) as a model substrate. Malpighian tubules rapidly accumulated FL via a high affinity process (Km = 7.75 micromol l(-1)); uptake was completely eliminated by the prototypical organic anion transport inhibitor probenecid (1 mmol l(-1)), but not by p-aminohippuric acid (3 mmol l(-1)). FL uptake was inhibited by monocarboxylic acids at a high concentration (3 mmol l(-1)), and inhibition was more effective with an increase in the carbon chain of the monocarboxylic acid (37% inhibition by 5-carbon valeric acid, and 89% inhibition by 7-carbon caprylic acid). Likewise, tests using a series of aliphatic glutathione conjugates indicated that only the compound with the longest side-chain (decyl-glutathione) significantly inhibited FL uptake (81% inhibition). FL uptake was inhibited by a number of xenobiotics, including a plant alkaloid (quinine), herbicides (2,4-dichlorophenoxyacetic acid and 4-(2,4-dichlorophenoxy)-butyric acid), and the insecticide metabolites malathion monocarboxylic acid (MMA) and 3-phenoxybenzoic acid (PBA), suggesting that this transport system plays an active role in excretion of xenobiotics from Acheta by Malpighian tubules. HPLC quantification of MMA and PBA accumulation into Malpighian tubules verified that MMA accumulation was via a mediated transport process, but suggested that PBA accumulation was by nonspecific binding. The presence of a transport system in Malpighian tubules that handles at least one pesticide metabolite (MMA) suggests that transport processes could be a mechanism conferring resistance to xenobiotic exposure in insects.

Animals↗

PubMed1985

Short-chain fatty acids in the small-bowel bacterial overgrowth syndrome.

The short-chain fatty acids (SCFAs) have been measured by gas chromatography in fasting jejunal secretions, saliva, and feces from 8 patients with the small-bowel bacterial overgrowth syndrome (BO) and 9 control patients; in jejunal secretions and saliva from 6 healthy subjects; and in feces from 20 healthy subjects. The concentrations of SCFAs (median (range), mumol/l) in jejunal secretions of BO patients were as follows: total, 990 (210-12,370); acetic acid, 650 (170-6770); propionic acid, 110 (16-3070); isobutyric acid, 26 (1-310); n-butyric acid, 90 (12-1340); isovaleric acid, 35 (2-680); n-valeric acid, 7 (3-200). In BO patients the total concentration of SCFAs in jejunal secretions was approximately four times higher than in control patients (p less than 0.01) and in healthy subjects (p less than 0.025). The relative distribution of the acids resembled the distribution found in feces more than that of saliva or the normal jejunal secretions. These findings indicate that patients with BO have a colon-like flora in the small intestine and that the main part of the SCFAs in the jejunal secretions of these patients is produced by the altered microbial flora in the jejunum. Combined with other tests, analyses of intestinal SCFAs may prove to be valuable in the diagnosis of small-bowel bacterial overgrowth.

Adult↗

PubMed2003

Characterisation of aerobic bio treatment of meat plant effluent.

Primary treated meat processing plant effluent was characterised for the calibration of the ASM 2 model. The total COD of the wastewater was 500-2,000 mg L(-1). The wastewater contained 15-18% of RBCOD. RBCOD of the meat processing wastewater was from short chain fatty acids (SCFA). Acetic and iso-valeric acids contributed 50% of the total SCFA COD. The inert soluble and particulate COD fractions were each 4%. The COD exerted by carbohydrate was 5% of the total COD. Fat and protein contributed 51% and 44% of the total COD of the wastewater respectively. The average concentrations of ammonia, total phosphorus, total suspended solids and alkalinity were 75 mg L(-1), 34 mg L(-1), 450 mg L(-1) and 275 mg L(-1) CaCO3 respectively. Maximum specific growth rates of heterotrophs and autotrophs were between 1.2-2.5 day(-1) and 0.65-0.8 day(-1). The heterotrophs yield coefficient was 0.63 on a COD basis.

Bacteria, Aerobic↗

PubMed1989

[Direct gas chromatography analysis of volatile fatty acids and lactic acids in microbiological diagnosis].

The gas chromatographic analysis of short-chain fatty acids is of great significance in the rapid diagnosis of anaerobic infections and bacterial meningitis. A new analytical method is presented detecting lactic acid without prior derivatisation in addition to volatile fatty acids in the aqueous phase directly. Lactic acid levels greater than 30 mg/dl are measured in cerebrospinal fluids of patients with acute bacterial meningitis. The sole detection of acetic acid in concentrations higher than 20 mg/dl indicates aerobes in clinical materials. A high correlation exists between the determination of n-butyric acid as well as iso-valeric acid and the occurrence of anaerobic bacteria.

Bacteria, Anaerobic↗

PubMed1983

[Volatile fatty acids in the rumen of sheep fed a synthetic diet].

A trial was conducted with wethers to study the effect of the administration of a synthetic diet (composition: 30.125% starch, 30.125% sucrose, 25% cellulose, 5.25% urea, 8.125% mineral supplement, 1.25% maize oil and 0.125% cholinechloride) upon rumen fermentation. The adaptation to the synthetic diet lasted three months, the proportion of the synthetic diet increasing every week (by 10%) to the detriment of a traditional diet (composition: 0.5 kg meadow hay, 0.3 kg barley, 0.2 kg wheat bran, salt and straw ad libitum). In the 10th week the animals consumed 0.5 kg granular synthetic diet, 0.2 kg cellulose flakes and 0.01 kg polystyrene. After three weeks of the administration of the fully synthetic diet, the rumen fluid was sampled after morning feeding in intervals of 0, 1, 3, 5 and 7 hours. In the dynamics of fermentation, statistically significant differences were found only in isobutyric and isovaleric acid between the 0th and 1st and between the 5th and 7th hours (P less than 0.05--P less than 0.001). The data for all the time intervals were recalculated to average values. These were as follows: total volatile fatty acids 63.03 mmol/l, acetic acid 51.00 mol%, propionic acid 26.75 mol%, butyric acid 19.43 mol%, isobutyric acid 0.91 mol%, isovaleric 1.27 mol%, valeric acid 0.62 mol%, energy efficiency of VFA production 78.23%. The obtained data are confronted with literary data on synthetic diets which contained urea and various energy sources.

Animal Feed↗

PubMed1979

An analysis of [3H]gamma-aminobutyric acid (GABA) binding in the human brain.

The binding of [3H]GABA to membranes prepared from human brains obtained post morten was examined. This binding was independent of patient sex, age (16--80 years), postmortem interval (4--33 h) or storage time when frozen (0-64 months). In preparations from cerebellar cortex various compounds displaced [3H]GABA binding with the following order of potency: muscimol greater than 3-aminopropanesulfonic acid greater than GABA greater than imidazoleacet acid greater than delta-amino-n-valeric acid greater than 3-hydroxyGABA greater than bicuculline. Other compounds active 'in vitro' included strychnine, homocarnosine and some (e.g. clozapine, thioridazine, pimozide) but not all (chlorpromazine, haloperiodol) neuroleptics. Compounds inactive 'in vitro' included aminooxyacetic acid, baclofen, picrotoxin, anticholinergics, metrazole, anticonvulsants and naloxone. Triton X-100 augmented the [3H]GABA binding (25 nM) by about 10--20-fold in most brain regions. [3H]GABA binding (IC50) was altered in Huntington's chorea and Reye's syndrome, but not in schizophrenics (4-neuroleptic-treated patients) or sudden infant death syndrome. The data presented strongly support the proposal that the measurement of [3H]GABA binding in postmortem human brain offers a reflection of the state of the physiologically relevant GABA receptor.

Adolescent↗

PubMed1985

Serum branched chain amino and keto acid response to fasting in humans.

Eight healthy individuals were fasted for 72 hours. The concentrations of the branched chain keto acids (BCKA), branched chain amino acids (BCAA), C peptide, and glucagon were determined in peripheral venous blood. alpha-ketoisocaproic acid, alpha-keto-beta-methyl-n-valeric acid, and alpha-ketoisovaleric acid increased significantly within 36 hours along with the corresponding amino acids. After 60 hours of starvation, the concentrations of BCKA and BCAA declined despite the fact that the subjects were still in the fasting state. These changes were accompanied by a decrease in the concentrations of C peptide and an increase in glucagon levels. It is suggested that in starving man insulinopenia may contribute to the rise in BCKA concentrations and that the increase in BCKA may be a mechanism to reduce proteolysis.

3-Hydroxybutyric Acid↗

PubMed1987

The effects of excitatory amino acids and their antagonists on the generation of motor activity in the isolated chick spinal cord.

We have investigated the action of excitatory amino acids and their antagonists on spontaneous motor activity produced by an isolated preparation of the chick lumbosacral cord. Bath application of N-methyl-DL-aspartic acid (NMDA) or D-glutamate increased the occurrence and duration of spontaneous episodes of motor activity. Both NMDA-induced and spontaneous activity were reversibly inhibited by several excitatory amino acid antagonists including 2-amino-5-phosphono valeric acid and gamma-D-glutamyl glycine in a dose-dependent manner. These results suggest that motor activity in the chick spinal cord may be regulated by the release of endogenous excitatory amino acids from spinal interneurons.

2-Amino-5-phosphonovalerate↗