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PubMed1986

Characteristics of methanogens isolated from bovine rumen.

Six strains of methanogens were isolated from 10(-8) and 10(-9) ml of bovine rumen contents. All strains had the morphologic and physiologic characteristics of Methanobrevibacter spp. Four strains required coenzyme M; two did not. Growth of all strains either depended on or was stimulated by a mixture of isobutyric, isovaleric, 2-methylbutyric, and valeric acids. None of the strains reacted with antiserum against the type strain of Methanobrevibacter ruminantium.

Animals↗

PubMed1986

Structure and dynamics of anaerobic bacterial aggregates in a gas-lift reactor.

Anaerobic mixed-culture aggregates, which converted glucose to acetic, propionic, butyric, and valeric acids, were formed under controlled conditions of substrate feed (carbon limitation) and hydraulic regimen. The continuous-flow system used (anaerobic gas-lift reactor) was designed to retain bacterial aggregates in a well-mixed reactor. Carrier availability (i.e., liquid-suspended sand grains) proved necessary for bacterial aggregate formation from individual cells during reactor start-up. Electron microscopic examination revealed that incipient colonization of sand grains by bacteria from the bulk liquid occurred in surface irregularities, conceivably reflecting local quiescence. Subsequent confluent biofilm formation on sand grains proved to be unstable, however. Substrate depletion in the bulk liquid is assumed to weaken deeper parts of the biofilm due to cellular lysis, after which production of gas bubbles and liquid shearing forces cause sloughing. The resulting fragments, although sand free, were nevertheless large enough to be retained in the reactor and gradually grew larger through bacterial growth and by clumping together with other fragments. In the final steady state, high cell densities were maintained in the form of aggregates, while sand had virtually disappeared due to sampling losses and wash-out. Numerical cell densities within aggregates ranged from 10/ml at the periphery to very low values in the center. The cells were enmeshed in a polymer matrix containing polysaccharides; nevertheless, carbon sufficiency was not a prerequisite to sustain high hold-up ratios.

Journal Article↗

PubMed1986

Factors responsible for increased susceptibility of mice to intestinal colonization after treatment with streptomycin.

Streptomycin sulfate (5 mg/ml) was added to the drinking water of Swiss white mice. After treatment for 1 week, the mice were challenged orogastrically with 10(8) Pseudomonas aeruginosa cells. The organism failed to multiply in the intestinal tract of either treated or untreated animals, but could be recovered from contents and tissues after 48 h. In a previous study, Salmonella typhimurium was shown to multiply in the intestines of streptomycin-treated but not untreated mice when 10(3) organisms were used as inoculum. Streptomycin administration had little effect on Eh, protein or carbohydrate concentrations of cecal contents, or intestinal motility. However, it caused a statistically significant increase in water content and pH of contents and a decrease in the concentrations of acetic, propionic, butyric, and valeric acids. S. typhimurium multiplied in pooled cecal contents obtained from both streptomycin-treated and untreated animals, but its multiplication rate and total populations were significantly greater in contents from treated animals. P. aeruginosa did not multiply in contents from either treated or untreated mice. Similar results were obtained when the organisms were inoculated into nutrient broth adjusted to simulate the pH levels and volatile fatty acid (VFA) concentrations in cecal contents of treated and untreated mice. The addition of brain heart infusion broth to cecal contents from untreated animals, in concentrations that support multiplication of S. typhimurium and P. aeruginosa, did not reverse inhibition. The addition of VFA to cecal contents from treated animals to equal the concentration in cecal contents from untreated animals caused inhibition of a magnitude observed in cecal contents from untreated animals. The results indicate that VFA operating at the pH level of cecal contents of conventional mice inhibit the multiplication of both S. typhimurium and P. aeruginosa and restrict colonization of the intestine by these organisms. The decrease in VFA concentrations that occurs as a result of streptomycin administration adequately explains the increased susceptibility of treated mice to colonization with S. typhimurium. It does not explain the increased susceptibility of treated mice to P. aeruginosa colonization, however.

Animals↗

PubMed1964

PHYSIOLOGY OF THE SPORULATION PROCESS IN CLOSTRIDIUM BOTULINUM. II. MATURATION OF FORESPORES.

Day, Lawrence E., (Michigan State University, East Lansing) and Ralph N. Costilow. Physiology of the sporulation process in Clostridium botulinum. II. Maturation of forespores. J. Bacteriol. 88:695-701. 1964.-Clostridium botulinum, strain 62-A, did not sporulate endotrophically, but forespores matured to refractile, heat-resistant spores when replaced in solutions containing l-alanine and l-proline, l-isoleucine and l-proline, or l-alanine and l-arginine. Solutions of l-arginine or l-citrulline would not support the maturation process. Acetate, CO(2), and delta-amino valeric acid were produced during sporulation in a replacement solution of l-alanine and l-proline, indicating the operation of the Stickland reaction. There was no large uptake of either exogenous l-alanine or acetate during this process. Similarly, there was no apparent protein or nucleic acid synthesis, since high levels of chloramphenicol, 8-azaguanine, or mitomycin C failed to inhibit, and no significant amount of P(32) was incorporated into the spore nucleic acids. Dipicolinic acid (DPA) was synthesized during forespore maturation. It is believed that these final steps in sporulation of C. botulinum require only an exogenous source of energy which can be obtained via the Stickland reaction system, and that the synthesis of DPA and other unknown materials relies primarily on endogenous substrates.

Acetates↗

PubMed1996

Modulation of spinal visceral nociceptive transmission by NMDA receptor activation in the rat.

1. Thirty-three neurons in the L6-Sl spinal cord of 30 adult male Sprague-Dawley rats were characterized for responses to colorectal distention (CRD, 20-80 mmHg, 20 s) and convergent cutaneous receptive fields in the presence and absence of N-methyl-D-aspartate (NMDA; 1 microM) or D-serine (1 microM) administered locally by pressure ejection. 2. NMDA ejected locally increased the resting (spontaneous) activity, responses to CRD, postdistention afterdischarges, encoding of visceral nociception, and the size of convergent cutaneous receptive fields of some neurons. Facilitation of responses to noxious intensities of CRD (> or = 40 mmHg) was apparent between 30 s and 4 min after drug ejection. The slope of stimulus-response functions to graded intensities of CRD was increased significantly by NMDA, although mean response threshold was not significantly altered after NMDA ejection. 3. Facilitatory effects of NMDA on responses to CRD and increases in size of convergent cutaneous receptive fields were blocked or reversed by administration of the NMDA receptor antagonist, 5-amino-2-phosphono-valeric acid. 4. D-serine, an agonist at the glycine modulatory site on the NMDA receptor complex, generally mimicked the effects of NMDA on neurons responsive to CRD. The effects of D-serine were blocked by the glycine site antagonist 7-chloro-kynurenic acid (7-CK). 7-CK also blocked NMDA-produced effects on responses to CRD and increases in size of cutaneous receptive fields. 5. No differences were found between spinal neurons with and without documented long ascending projections with respect to effects of NMDA or D-serine. 6. These findings demonstrate involvement of spinal NMDA receptors in mediating hyperexcitability of spinal neurons to visceral nociceptive input and suggest an important contribution of spinal NMDA receptors in visceral hyperalgesic syndromes.

2-Amino-5-phosphonovalerate↗

PubMed1990

Guanidino compound analysis as a complementary diagnostic parameter for hyperargininemia: follow-up of guanidino compound levels during therapy.

The aim of this collaborative study was to investigate whether guanidino compound analyses in the biologic fluids can be used as a complementary diagnostic parameter for hyperargininemia. Guanidino compounds were determined in the biologic fluids of all known living hyperargininemic patients using a cation exchange chromatographic system with a fluorescence detection method. The serum arginine, homoarginine, alpha-keto-delta-guanidino-valeric acid, argininic acid, and N-alpha-acetylarginine levels of all the hyperargininemic patients are higher than the normal range. Similar increases were seen for the urinary excretion of alpha-keto-delta-guanidinovaleric acid and argininic acid. Untreated hyperargininemic patients have the highest guanidino compound levels in cerebrospinal fluid. However, even under therapy, the arginine, homoarginine, alpha-keto-delta-guanidinovaleric acid, and argininic acid levels in cerebrospinal fluid are still increased. Protein restriction alone is not sufficient to normalize the hyperargininemia, but protein restriction together with supplementation of essential amino acids with or without sodium benzoate decreases further the arginine levels. However, whereas the argininemia can be normalized, the catabolites of arginine are still increased. We conclude that the urinary amino acid levels may remain normal in hyperargininemia, whereas consistent increases of the guanidino compounds are observed. Thus, guanidino compound analyses can be used as a complementary biochemical diagnostic parameter for hyperargininemia. Although the argininemia can be normalized by therapy, the levels of the catabolites of arginine are still elevated.

Adolescent↗

PubMed1990

A role for N-methyl-D-aspartate (NMDA) receptors in the control of LH secretion and initiation of female puberty.

The physiological role of N-methyl-D-aspartate (NMDA) receptors in controlling LH secretion and the initiation of puberty was investigated using two specific antagonists, MK-801 and DL-2-amino-5-phosphono valeric acid (AP-5). Single daily sc injections of MK-801 (0.1-0.2 mg/kg BW), a noncompetitive NMDA receptor antagonist, given to prepubertal rats significantly delayed but did not prevent the timing of puberty, as determined by the age at vaginal opening and first ovulation. Infusion of MK-801 (5 micrograms/h) via osmotic minipumps for 4 days inhibited the postovariectomy rise of LH secretion in prepubertal rats. Both MK-801 (0.2 mg/kg BW, sc) and AP-5 (4 x 30 mg, iv), a competitive NMDA receptor antagonist, blocked the estradiol-induced LH surge in prepubertal ovariectomized rats. These results demonstrate that blockade of NMDA receptors can prevent the development of enhanced LH secretion in female rats undergoing sexual maturation. Moreover, they support the view that activation of NMDA receptors significantly contributes to the physiological initiation of the pubertal process.

2-Amino-5-phosphonovalerate↗

PubMed2003

Improvement of (+)-catechin inhibitory activity on human PMN respiratory burst by (+)-3-O-propionyl and (-)-3-O-valeryl substitution.

Catechins and their derivatives are abundant flavanols in the plant kingdom. Usually, catechin activity correlates with chemical structure. We hypothesized that by adding hydrophobic groups to the native catechin, we could ameliorate penetration of the cell and make the derivatives more active than native molecule in inhibiting polymorphonuclear leucocyte (PMN) oxidative burst. This study was designed to compare the antioxidant activity of native catechin with that of (+)-3-propionylcatechin and (-)-3-Ovalerylcatechin esters by two cell-free colorimetric methods and by their effects on whole blood leucocytes as well as on isolated PMN chemiluminescence activity. The results showed that the colorimetric methods did not detect differences between catechins. On the contrary, cellular chemiluminescence studies showed that light emission by resting, as well as by phorbol myristate acetate (PMA)-stimulated PMNs and whole blood leucocytes was inhibited by catechin esters more intensively than native catechin. The compartmental chemiluminescence evaluation showed that the extracellular activity was similar with all catechins, while the intracellular activity was higher with esters. PMN pre-incubation, with catechins at various times before stimulation with PMA, enhanced the inhibitory activity of all compounds. Since the esterification with propionic or valeric acid increased the lipophilicity of (+)-catechin, we hypothesized that native and esterified catechins have different intracellular availability and therefore differ in effectiveness. An ancillary result obtained is that a single approach, chemical or cellular, is not sufficient to evaluate overall antioxidant activity in biological sytems. The results indicate that modified catechins may be very intriguing as possible future leucocyte modulating drugs, with possible applications in vascular and inflammatory diseases.

Antioxidants↗

PubMed2002

The study on a PVC membrane electrode for gemfibrozil.

In this paper, a poly(vinyl chloride) (PVC) membrane electrode is prepared for gemfibrozil, 2, 2-dimethyl-5-(2,5-xylyloxy) valeric acid, based on its ion pair complexes with hexadecyltrioctyl ammonium iodide (HTOA). The membrane composition of the electrode was optimized by using the sequential level elimination method for orthogonal experimental design. The electrode has a Nernstian response range from 2.5 x 10(-5) to 0.1 mol/l with an average slope of 55.3 mV/decade. The limit of detection is 7.1 x 10(-6) mol/l. The electrode responses were not affected by pH in the range 10.0-12.3. A Na2B4O7-Na2CO3 buffer of pH = 11.0 was selected as the background electrolyte solution for potentiometric measurements. The electrode was used for determining gemfibrozil in pharmaceutical preparations with satisfactory results.

Electrodes↗

PubMed2000

Anaerobic digestion from residue of industrial cassava industrialization with acidogenic and methanogenic physical separation phases.

A trial was carried out in a continuous regimen, using a completely stirred tank reactor, at acidogenic phase, and a hybrid reactor (upflow anaerobic sludge blanket + fixed bed) at methanogenic phase at room temperature. The residue to be treated came from a flour and cassava meal industry, and the reactors operated for 300 d with affluent chemical oxygen demand (COD) concentrations of 7500, 9000, 11,000, and 14,000 mg/L. The final results showed a biogas production with a content of 80% methane and an average reduction of COD and free cyanide of nearly 96 and 98%, respectively. The separation of phases selected bacterial groups. At acidogenic phase, a predominance of propionic, n-butyric, and n-valeric acids, as well as a biomass composed of 95% fermentative bacilli, which were responsible for a 90% reduction in free cyanide concentration, was observed. At methanogenic phase, a predominance of methanogenic bacteria that came only from the Methanothrix genus was observed. The bacteria were responsible for high levels of organic matter removal and methane production.

Anaerobiosis↗

PubMed2002

Sphaerotilus natans isolated from activated sludge and its production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate).

Sphaerotilus natans is a sheathed bacterium existing in the activated sludge of wastewater treatment plants. It is one of the filamentous bacteria causing the bulking and foaming difficulties of activated sludge. Isolating the strain and culturing it in an axenic environment could not only provide the metabolic knowledge of the strains that would be useful in the development of wastewater treatment methods, but also could enable us to gain an understanding of the mechanism by which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (poly[3-HB-co-3-HV]) is produced by this strain. This article reports the screening and isolation of the strain from the activated sludge using the Nile blue staining method together with Fourier transform infrared analysis. We investigated the ability of the selected strain to produce poly(3-HB-co-3-HV) copolymer using glucose and peptone, or by adding valeric acid or sodium propionate as precursor. Proper precursor feeding could dramatically enhance its 3HV content in the copolymer P(3HB-co-3HV). By controlling the different feeding times in fed-batch fermentation, different desired copolymers were obtained with 15, 40, and 70% 3HV mole fraction of the copolymer. Polymer properties were analyzed by gas chromatography, differential scanning calorimetry, thermo-gravimetry, and nuclear magnetic resonance analysis.

3-Hydroxybutyric Acid↗

PubMed2004

Multiple forms of long-term potentiation and long-term depression converge on a single interneuron in the leech CNS.

Long-term potentiation (LTP) of synaptic transmission was observed in two types of synapses that converge on the same postsynaptic neuron in the leech CNS. These synapses were made by identifiable sensory neurons, the mechanosensory touch (T-) and pressure (P-) cells, onto the S-cell, an interneuron critical for certain forms of learning. Changes in both the T-S and P-S synapses appear to be activity dependent because LTP was restricted to inputs that had undergone tetanization; however, properties of synaptic plasticity at the T-S and P-S connections differ considerably. At the P-S synapse, LTP was induced in the tetanized synapse but not in the nontetanized synapse tested in parallel. P-S LTP was blocked by the NMDA receptor antagonist dl-2-amino-5-phosphono-valeric acid (AP-5) or by lowering the extracellular concentration of glycine, an NMDA receptor (NMDAR) co-agonist. P-S LTP was strongly affected by the initial amplitude of the synaptic potential at the time LTP was induced. Smaller amplitude synapses (<3.5 mV) underwent robust potentiation, whereas the less common, larger amplitude synapse (>3.5 mV) depressed after tetanization. At the T-S synapse, tetanization simultaneously induced homosynaptic LTP in the tetanized input and heterosynaptic long-term depression (LTD) in the input made by a nontetanized T-cell onto the same S-cell. Interestingly, AP-5 failed to block homosynaptic LTP at the T-S synapse but did prevent heterosynaptic LTD. T-S LTP was not affected by the initial EPSP amplitude. Thus, leech neurons exhibit synaptic plasticity with properties similar to LTP and LTD found in the vertebrate nervous system.

Animals↗

PubMed1981

[Occupational impairment of the olfactory sense of chromate producing workers (author's transl)].

Using T & T Olfactometer which had been developed and standardized for clinical use in Japan recently, measurements of olfactory thresholds of odor detection and of odor recognition were carried out on 33 subjects (26 males and 7 females), who had worked in a chromate producing factory. The subjects had left the factory before 7 years or more. Five kinds of test odors were used; beta-phenyl ethyl alcohol, methyl cyclopentenolone, iso-valeric acid, gamma-undecalactone, and scatol. The degree of olfaction loss was expressed with the number of powers of 10 in series of multiple concentrations by 10 of each test odor with reference to the concentration of the detection threshold of young normal people. Seventeen of 33 subjects (51.4%) had a perforation of the nasal septum. Middle and high grade decrease of odor recognition faculty were found in 18 (54.5%) including 2 anosmia, one of whom complained also of the disorder of taste. Any specific pattern of olfactogram characterizing them were not found, namely, chromates impair olfactory sense for all kinds of odors, which means the impairment of olfactory epithelium itself. The degree of olfaction loss was related to the duration of employment in the chromate producing factory. The existence of septal perforation had no direct relation to the degree of olfaction loss.

Adult↗

PubMed2006

Optimised anaerobic treatment of house-sorted biodegradable waste and slaughterhouse waste in a high loaded half technical scale digester.

Anaerobic co-digestion of organic wastes from households, slaughterhouses and meat processing industries was optimised in a half technical scale plant. The plant was operated for 130 days using two different substrates under organic loading rates of 10 and 12 kgCOD.m(-3).d(-1). Since the substrates were rich in fat and protein components (TKN: 12 g.kg(-1) the treatment was challenging. The process was monitored on-line and in the laboratory. It was demonstrated that an intensive and stable co-digestion of partly hydrolysed organic waste and protein rich slaughterhouse waste can be achieved in the balance of inconsistent pH and buffering NH4-N. In the first experimental period the reduction of the substrate COD was almost complete in an overall stable process (COD reduction >82%). In the second period methane productivity increased, but certain intermediate products accumulated constantly. Process design options for a second digestion phase for advanced degradation were investigated. Potential causes for slow and reduced propionic and valeric acid degradation were assessed. Recommendations for full-scale process implementation can be made from the experimental results reported. The highly loaded and stable codigestion of these substrates may be a good technical and economic treatment alternative.

Abattoirs↗

PubMed2004

Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet.

Four Duroc x White composite crossbred (21.8 +/- 1.0 kg BW) and four 12-wk-old Meishan purebred (20.7 +/- 1.6 kg BW) growing barrows were used to determine the relative breed differences in metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume 700 g of a diet containing 35% (as-fed basis) dehydrated alfalfa meal once daily. The pigs' daily intakes of DM, N, GE, NDF, and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery, a 3-d total urine and feces collection was conducted. On d 24 after surgery, each pig was placed in an open-circuit calorimeter, and its catheters were connected to a system for simultaneous measurements of oxygen consumption by portal-drained viscera and by whole body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 after surgery. There were no differences (P = 0.13) between the first and second collections in apparent total-tract digestibility coefficients for nutrients and N retention of pigs. Compared with Duroc x White composite crossbred pigs, Meishan pigs had lower (P = 0.05) apparent digestibility coefficients for DM, N, NDF, hemicellulose, and N retention, but their portal-drained viscera used a greater (P = 0.05) fraction of whole-body oxygen consumption. No differences (P = 0.12) were found between Duroc x White composite crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting the energy needs for whole-body heat production. These results indicate that, in contrast to previous beliefs, the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.

Animal Feed↗

PubMed1984

Species differences in the in vitro metabolism of phencyclidine.

The metabolism of 1-(1-phenylcyclohexyl)-piperidine (phencyclidine or PCP) by liver preparations from cat, monkey, rabbit and rat has been studied. 4-Phenyl-4-piperidinocyclohexanol (I), 1-1-phenylcyclohexyl-4-hydroxy-piperidine (II), N-(5-hydroxypentyl)-1-phenylcyclohexylamine (IX) and 5-(1-phenylcyclohexylamino)-valeric acid (X) were found in all species, but liver preparations of rat and rabbit were much more active than those of cat or monkey in metabolizing PCP. Only rabbit produced 4-(4'-hydroxypiperidino)-4-phenylcyclohexanol (III) in amounts detectable by g.l.c. Mass balance calculations of PCP, I, II, III, IX and X in the cat, monkey and rat indicate that other metabolic pathways not measured in this study are operative.

Animals↗

PubMed1989

Effect of the combination of monensin and isoacids on rumen fermentation in vitro.

Effects of isoacids, monensin, or a combination of them on fermentation by mixed rumen bacteria were investigated using a continuous culture technique. The culture was allowed to stabilize for 4 d before treatments were imposed. Comparisons between treatments were made on d 11 and 12 of the culture. Isoacids (equal proportions of isobutyric, 2-M-butyric, isovaleric, and valeric acids) at 15 mg/dl of culture media increased acetate (6.17 vs. 5.48 meq/dl) and total VFA production (8.93 vs. 7.87 meq/dl) compared with that of controls. Monensin at 150 micrograms/dl reduced acetate (3.74 vs. 6.02 meq/dl) and VFA (6.84 vs. 8.54 meq/dl) but increased propionate (2.28 vs. 1.74 meq/dl) relative to control. The combination of isoacids and monensin increased acetate relative to monensin alone (5.24 vs. 3.74 meq/dl) but did not alter the effect of monensin on propionate concentration (2.32 vs. 2.28 meq/dl). It is concluded that monensin decreases acetate production by 35% and when isoacids are added to the cultures containing monensin, acetate production is restored.

Animals↗

PubMed1976

[Biotransformation of diflucortolone valerate in the skin of rat, guinea pig and man (author's transl)].

The biotransformation of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolone valerate, DFV, Nerisona) was examined in vitro in the skin of rat and man and in vivo in the skin of guinea pigs. In the investigations with rat skin DFV in ethanolic solution (0.1 mumol) was added and the ester hydrolysis in buffer monitored in relation to the incubation time. In the experiments with guinea pigs and with human skin DFV was applied topically in the form of a 0.1% W/O emusion employing a dose of 6 mg/cm2 skin. After the substance which had not penetrated had been recovered by means of cotton wool and adhesive film at the end of the period of exposure the portions of skin were homogenized, extracted and the extracts separated by thin-layer chromatography. DFV is hydrolysed in the skin of rats and guinea pigs with a half-life of about 30-60 min to diflucortolone 6alpha,9-difluoro-11bets,21-dihydroxy-16alpha-methyl-1,4-pregnadiene-3,20-dione) and valeric acid. In excised human skin degradation of the ester proceeds much more slowly. Even 7 h p. appl. about 80-90% DFV and only 5-15% DF were identifiable in the skin extract. Despite the estremely low absorption rate the slow hydrolysis of DFV in human skin guarantees an adequate level of active ingredient in the skin over a long period.

Administration, Topical↗