The contribution of water soluble and water insoluble organic fractions to oxygen uptake rate during high rate composting

This study aims to establish the contribution of the water soluble and water insoluble organic fractions to total oxygen uptake rate during high rate composting process of a mixture of organic fraction of municipal solid waste and lignocellulosic material. This mixture was composted using a 20 l self-heating pilot scale composter for 250 h. The composter was fully equipped to record both the biomass-temperature and oxygen uptake rate. Representative compost samples were taken at 0, 70, 100, 110, 160, and 250 h from starting time. Compost samples were fractionated in water soluble and water insoluble fractions. The water soluble fraction was then fractionated in hydrophilic, hydrophobic, and neutral hydrophobic fractions. Each fraction was then studied using quantitative (total organic carbon) and qualitative analysis (diffuse reflectance infrared spectroscopy and biodegradability test). Oxygen uptake rates were high during the initial stages of the process due to rapid degradation of the soluble degradable organic fraction (hydrophilic plus hydrophobic fractions). Once this fraction was depleted, polymer hydrolysis accounted for most of the oxygen uptake rate. Finally, oxygen uptake rate could be modeled using a two term kinetic. The first term provides the oxygen uptake rate resulting from the microbial growth kinetic type on easily available, no-limiting substrate (soluble fraction), while the second term considers the oxygen uptake rate caused by the degradation of substrate produced by polymer hydrolysis.     

Reaction System of Haemophilus,Superhelical DNA-relaxing Enzyme is Useful for Screening of DNA-binding Substance

Several substances with antioxidant activity were isolated from the mixture of dehydroascorbic acid and tryptophan when reacted together in ethanol. One of the main antioxidant products was obtained in crystalline form from an n-butanol extract of the reaction mixture by means of Sephadex column chromatography followed by HPLC with a reversed phase column. ¹H- and ¹³C-NMR of the product and its acetate showed its structure as a condensate of dehydroascorbic acid and tryptophan with each single molecule involving a C-spiro structure. By a POV test the activity of this substance was about two-thirds of that of BHA on a molar basis, and the activity of the reaction mixture is greatly attributable to this substance.     

Effect of palmitoylcarnitine on mitochondrial activities

Mitochondria from pea (Pisum sativum L.) cotyledons and potato (Solanum tuberosum L.) tubers exhibited a palmitoyl carnitine-dependent, KCN-sensitive stimulation of the oxygen uptake measured in the presence of 0.2mmol·^–1 malate (sparker malate), provided a certain concentration range of palmitoylcarnitine was observed. Above this concentration range, which was dependent on the bovine serum albumin (BSA) concentration of the reaction mixture, the mitochondrial oxygen uptake was inhibited by palmitoylcarnitine. Palmitoylcarnitine (racemate) and palmitoyl-l-carnitine were equally effective in stimulating/inhibiting mitochondrial oxygen uptake in the presence of sparker malate. The mitochondrial membrane potential generated in the presence of sparker malate was partially dissipated by palmitoyl-lcarnitine concentrations stimulating the mitochondrial oxygen uptake. The formation of acid-soluble radioactivity in reaction mixtures provided with [1-¹⁴C]palmitoyll-carnitine was considerably lower than that expected minimally if the palmitoyl-l-carnitine-stimulated oxygen uptake resulted from palmitoyl-l-carnitine oxidation sparked by malate. Palmitoylcarnitine concentrations resulting in stimulation of the mitochondrial oxygen uptake in the presence of sparker malate also led to a stimulation of succinate-cytochrome c reductase activity, as well as to an increase in the measurable activities of mitochondrial matrix enzymes, indicating loss of both mitochondrial integrity and mitochondrial enzyme latency in the presence of palmitoylcarnitine. Correspondingly, malate-dependent NADH formation was stimulated by palmitoylcarnitine. Neither NAD reduction nor oxygen uptake were observed when the mitochondria were provided with palmitoylcarnitine only. The oxygen uptake due to glycine oxidation by mitochondria from green sunflower (Helianthus annuus L.) cotyledons was affected by palmitoylcarnitine in a similar manner to the oxygen uptake of pea cotyledon and potato tuber mitochondria in the presence of sparker malate. The results lead to the conclusion that the palmitoylcarnitine-dependent stimulation of mitochondrial oxygen uptake observed in the presence of sparker malate results substantially from an enhanced malate oxidation due to the detergent effect of palmitoylcarnitine on the mitochondrial membranes, rather than from palmitoylcarnitine -oxidation.Abbreviations BSA bovine serum albumin - CCCP carbonylcyanide m-chlorophyenylhydrazone The work was supported by the Deutsche Forschungsgemeinschaft.     

The chemistry of flavins and flavoproteins. Aerobic photochemistry

1. When a mixture of FMN and a reducing substrate (e.g. unprotonated amine) is illuminated oxygen is consumed. 2. The rate of oxygen uptake increases as oxygen concentration falls with some substrates (type I reaction), but with other substrates (typically aromatic compounds) the rate falls as the oxygen concentration falls (type II reaction). 3. The kinetics of type I reactions with EDTA, dl-alpha-phenylglycine and diethanolamine are all consistent with a mechanism in which the rate-determining step, hydrogen abstraction by the FMN triplet, is followed by rapid reoxidation of reduced FMN by oxygen. The reaction is faster at low oxygen concentrations because oxygen quenches the triplet. 4. The sensitivity of reaction rates to substituents in dl-alpha-phenylglycine can be described by a Hammett rho value of -0.6. 5. Individual rate constants for quenching and reaction of the FMN triplet with substrate were calculated (2.4x10(8) and 2.1x10(7)m(-1)s(-1) respectively for EDTA) on the assumption that oxygen quenches the triplet in a diffusion-controlled reaction. 6. The pH-dependences of oxygen uptake rates with six natural amino acids as substrates were measured. 7. Photoinactivations of l-glutamate dehydrogenase and d-amino acid oxidase by FMN were demonstrated.     

Keto fatty acids not containing doubly allylic methylenes are lipoxygenase substrates

The soybean lipoxygenase I oxygenates the unusual substrate 12-keto-(9Z)-octadecenoic acid methyl ester as indicated by oxygen uptake and spectral changes of the incubation mixture. The main oxygenation products have been isolated by HPLC and identified as 9,12-diketo-(10E)-octadecenoic acid methyl ester and 12-keto-(10E)-dodecenoic acid methyl ester by UV and IR spectroscopy, cochromatography with an authentic standard, gas chromatography/mass spectroscopy, and 1H NMR. In the formation of both compounds the oxygenase and hydroperoxidase activities of the enzyme appear to be involved. These data and the earlier results on the oxygenation of furanoic fatty acids (Boyer et al., 1979) indicate that the lipoxygenase reaction is not restricted to substrates containing a 1,4-pentadiene structure.     

The expression of catechol oxidase activity during the hydroxylation of p-coumaric acid by spinach-beet phenolase

1. The conditions under which oxygen consumption in excess of that required for the hydroxylation of p-coumaric acid to caffeic acid, catalysed by spinach-beet phenolase, can be suppressed, have been examined. 2. With dimethyltetrahydropteridine as electron donor, oxygen uptake was exactly equivalent to the caffeic acid produced, provided that p-coumaric acid was in excess, but with excess of reductant, oxygen uptake caused by the further oxidation of caffeic acid was also observed. 3. With equal concentrations of ascorbate and p-coumaric acid, equivalent oxygen uptake and caffeic acid production was found only in the first stages of the reaction, whereas with NADH substituted for ascorbate, oxygen uptake was in excess throughout. 4. When ascorbate was used, the period of the reaction over which this equivalence was found was decreased at high reaction rates and not observed at all with aged enzyme preparations; equivalence was restored by adding bovine serum albumin to these aged preparations. 5. Equivalence between oxygen consumption and caffeic acid production was observed with NADH, if small quantities of dimethyltetrahydropteridine were also added. 6. It is concluded that hydroxylation proceeds without the concomitant production of caffeic acid only if the enzyme is stabilized for hydroxylation by p-coumaric acid and the reductant, and is protected from attack by o-quinones.     

Chronic effect of erythromycin on substrate biodegradation kinetics of activated sludge

This study evaluated the chronic impact of erythromycin, a macrolide antibiotic, on microbial activities, mainly focusing on changes in process kinetics induced on substrate biodegradation and all related biochemical processes of microbial metabolism. Experiments involved two fill/draw reactors sustained at steady state at two different sludge ages of 10 and 2.0 days, fed with peptone mixture and continuous erythromycin dosing of 50 mg/L. Oxygen uptake rate profiles were generated in a series of parallel batch reactors seeded with biomass from fill/draw systems at selected periods of steady-state operation. Experimental data were evaluated by model calibration reflecting inhibitory effect on process kinetics: continuous erythromycin dosing inhibited microbial growth, reduced the rate of hydrolysis, blocked substrate storage and accelerated endogenous respiration. Adverse impact was mainly due to changes inflicted on the composition of microbial community. Interruption of erythromycin feeding resulted in partial recovery of microbial response. Sludge age affected the nature of inhibition, indicating different process kinetics for faster growing microbial community. Kinetic evaluation additionally revealed the toxic effect of erythromycin, which inactivated a fraction of biomass. Mass balance using oxygen uptake rate data also identified a stoichiometric impact, where a fraction of available substrate, although completely removed, could not be utilized in metabolic activities.     

Bacteriology of Manganese Nodules: II. Manganese Oxidation by Cell-free Extract from a Manganese Nodule Bacterium

A cell-free extract from Arthrobacter 37, isolated from a manganese nodule from the Atlantic Ocean, exhibited enzymatic activity which accelerated manganese accretion to synthetic Mn-Fe oxide as well as to crushed manganese nodule. The reaction required oxygen and was inhibited by HgCl₂ and p-chloromercuribenzoate but not by Atebrine dihydrochloride. The rate of enzymatic action depended on the concentration of cell-free extract used. The enzymatic activity had a temperature optimum around 17.5 C and was destroyed by heating at 100 C. The amount of heat required for inactivation depended on the amount of nucleic acid in the preparation. In the cell-free extract, unlike the whole-cell preparation, peptone could not substitute for NaHCO₃ in the reaction mixture. An enzyme-containing protein fraction and a nucleic acid fraction could be separated from cell extract by gel filtration, when prepared in 3% NaCl but not in seawater. The nucleic acid fraction was not required for enzymatic activity.     

Inhibitory mechanisms of Maillard reaction products

In order to determine the inhibitory mechanism of antibacterial Maillard reaction products (MRP), heated mixtures containing arginine and xylose (AX) or histidine and glucose (HG) were studied for their mutagenic effect, using the Salmonella mutagenic test system ('Ames test'), with regard to their effect on the uptake of serine, glucose and oxygen and for their effect on iron solubility. It was found that the MRPs tested had little or no mutagenic effect, while an inhibitory effect on the uptake of serine, glucose and oxygen was observed. The MRPs also had an effect on the solubility of iron in nutrient broth and in phosphate buffer. While the AX mixture reduced the solubility of iron it was increased by the HG mixture. The reduction of iron solubility in the presence of the AX mixture was much greater at pH 8 than at pH 5. The present data suggest that the antibacterial effect of the MRPs tested is primarily due to the interaction between MRPs and iron, resulting in reduced oxygen uptake.     

Some properties of thyroidal membrane adenosinetriphosphatase and iodide uptake: effects of basic polyamino acids.

Poly L-lysine, poly L-ornithine, and histone significantly inhibited the iodide uptake by the thyroid slices, as previously reported. These basic polymers diminshed Na, K-ATPase and concomitantly markedly elevated Mg-ATPase activity in the NaI-treated microsomal preparation and the plasma membrane fraction obtained from thyroid. Poly L-glutamic acid, which was noneffetive to the iodide uptake in vitro, did not show such phenomenon. K-dependent p-nitrophenylphosphatase activity which is considered to reflect the terminal step of the reaction sequence of Na, K-ATPase was also inhibited by poly L-lysine. The effects mentioned above of poly L-lysine and other basic polyamino acids on membrane ATPase system were only found in the preparations from thyroid. The inhibitory effect of these reagents on thyroidal iodide uptake was discussed in terms of the change in membrane ATPase activities.     

Molecular characterization of fatty acid alpha-hydroperoxide-forming enzyme (alpha-oxygenase) in rice plants

Genes encoding an alpha-oxygenase, in Nicotiana tabacum and Arabidopsis thaliana, have been recently isolated. However, the reaction mechanism of the enzyme has not so far been elucidated. In this study, a cDNA encoding the fatty acid alpha-oxygenase gene in rice plants was isolated. The deduced amino acid sequence showed high similarity (63.6%) to that of N. tabacum. The gene was cloned into an expression vector system, pQE-30, and expressed in Escherichia coli as a host cell. Palmitic acid as a substrate was incubated with the lysate of the cells, and the products were analysed by HPLC. A compound formed predominantly by the recombinant enzyme was shown to be n-pentadecanal. By incubating the mixture at 0 degrees C, 2-hydroperoxypalmitic acid was detected as a primary product and little formation of n-pentadecanal was detected. Furthermore, uptake of molecular oxygen was observed with an oxygen electrode. This indicated that the gene in rice plants encodes the alpha-oxygenase.     

PROPERTIES OF THE UPTAKE AND RELEASE OF GLUTAMIC ACID BY SYNAPTOSOMES FROM RAT CEREBRAL CORTEX

Abstract– (1) The uptake and release of glutamic acid by guinea-pig cerebral cortex slices and rat synaptosomal fractions were studied, comparing the naturally occurring l - and non-natural d -isomers. Negligible metabolism of d -glutamic acid was observed in the slices. (2) Whereas in the cerebral slices the accumulation of glutamic acid was almost the same for the two isomers, d -glutamic acid was accumulated into the synaptosomal fraction at a markedly lower rate than was the L-isomer. (3) The uptake systems for d -isomer into the slices and synaptosomal fraction were found to be of single component, in contrast with the two component systems, high and low affinity components, for the uptake of l -glutamic acid. The apparent K_m values for the uptake of d -glutamic acid into the slices and synaptosomal fraction were comparable with those reported for the low affinity components for l -isomer. The uptake systems for d -glutamic acid were dependent on the presence of Na⁺ ions in the medium, like those for l -glutamic acid and GABA. (4) The evoked release of radioactive preloaded d -glutamic acid was observed both from the slices and synaptosomal fraction following stimulation by high K⁺ ions in the medium. From these observations, it is evident that the evoked release of an amino acid by depolarization in vitro is not necessarily accompanied by a high affinity uptake process. (5) The uptake of l -glutamic acid, expecially into the synaptosomal fraction, was highly resistant to ouabain. On the other hand, the uptake rate of d -glutamic acid and GABA into the synaptosomal fraction was inhibited by varying concentrations of ouabain in accordance with the inhibition for brain Na-K ATPase. (6) The uptake of l -glutamic acid into subfractions of the P₂ fraction was studied in relation to the distribution of the ‘synaptosomal marker enzymes’. An attempt to correlate the activities of enzymes of glutamic acid metabolism with the uptake of l -glutamic acid into the synaptosomal fraction from various parts of brain was unsuccessful. The high affinity uptake of l -glutamic acid was found to be very active in the synaptosomal fraction from any part of brain examined.     

Biodegradation of Maya crude oil fractions by bacterial strains and a defined mixed culture isolated from Cyperus laxus rhizosphere soil in a contaminated site

Ten bacterial strains were isolated by enrichment culture, using as carbon sources either aliphatics or an aromatic-polar mixture. Oxygen uptake rate was used as a criterion to determine culture transfer timing at each enrichment stage. Biodegradation of aliphatics (10,000 mg L(-1)) and an aromatic-polar mixture (5000 mg L(-1), 2:1) was evaluated for each of the bacterial strains and for a defined culture made up with a standardized mixture of the isolated strains. Degradation of total hydrocarbons (10,000 mg L(-1)) was also determined for the defined mixed culture. Five bacterial strains were able to degrade more than 50% of the aliphatic fraction. The most extensive biodegradation (74%) was obtained with strain Bs 9A, while strains Ps 2AP and UAM 10AP were able to degrade up to 15% of the aromatic-polar mixture. The defined mixed culture degraded 47% of the aliphatics and 6% of the aromatic-polar mixture. The defined mixed culture was able to degrade about 40% of the aliphatic fraction and 26% of the aromatic fraction when grown in the presence of total hydrocarbons, while these microorganisms did not consume the polar hydrocarbons fraction. The proposed strategy that combines enrichment culture together with oxygen uptake rate allowed the isolation of bacterial strains that are able to degrade specific hydrocarbons fractions at high consumption rates.     

Cyanide-insensitive oxidation of ascorbate + NNN''N''-tetramethyl-p-phenylenediamine mixture by mung-bean (Phaseolus aureus) mitochondria. An energy-linked function.

Freshly prepared washed or purified mung-bean (Phaseolus aureus) mitochondria utilize oxygen with ascorbate/tetramethyl-p-phenylenediamine mixture as electron donor in the presence of KCN. ATP control of the oxygen uptake can be observed with very fresh mitochondria. The electron flow, which is inhibited by antimycin A, salicylhydroxamic acid or octylguanidine, takes place by reversed electron transport through phosphorylation site II and thence to oxygen through the cyanide-insensitive pathway. Oligomycin and low concentrations of uncoupler partially inhibit the oxygen uptake in a manner similar to that observed for other energy-linked functions of plant mitochondria. An antimycin A-insensitive oxygen uptake occurs if high concentrations of uncoupler are used, indicating that the pathway of electron flow has been altered. The process of cyanide-insensitive ascorbate oxidation is self-starting, and, since it occurs in the presence of oligomycin, it is concluded that the reaction can be energized by a single energy-conservation site associated with the cyanide-insensitive oxidase pathway.     

Photosynthesis by isolated chloroplasts, simultaneous measurement of carbon assimilation and oxygen evolution

Photosynthetic carbon assimilation by isolated chloroplasts and its associated oxygen evolution were measured simultaneously in a single simplified reaction mixture. Each showed an initial lag prior to the attainment of the maximal rate and the photosynthetic quotient was unity during the period of illumination. Following illumination an oxygen uptake was observed in the dark which was not accompanied by any net release of newly fixed carbon dioxide.     

Studies on the relationship between the oxygen uptake and the release of amylase and sialic acid

The relationship between the oxygen uptake and the release of amylase and sialic acid induced by pilocarpine was investigated in dog submandibular glands. Pilocarpine dose-dependently stimulated the oxygen uptake. The dose required for the maximal response was 10 microM. The release of amylase and sialic acid induced by pilocarpine was inhibited by the addition of iodoacetic acid, malonic acid, 2, 4-dinitrophenol, antimycin A or sodium azide. The oxygen uptake induced by pilocarpine was significantly inhibited by iodoacetic acid, malonic acid, antimycin A or sodium azide. On the other hand, 2, 4-dinitrophenol further stimulated the oxygen uptake by pilocarpine. The increase in the oxygen uptake or the release of amylase and sialic acid induced by pilocarpine was significantly inhibited by ouabain. The Na+, K+-ATPase activity ratio in the microsomal fraction of dog submandibular glands was dose-dependently increased by pilocarpine. The Na+, K+-ATPase activity ratio induced by pilocarpine was significantly inhibited by ouabain, antimycin A, oligomycin or 2, 4-dinitrophenol. The pilocarpine-induced Na+, K+-ATPase activity ratio was significantly inhibited by the removal Ca2+ from the medium or the addition of 2 mM EGTA. These results suggest that the increase in the oxygen uptake by pilocarpine is profoundly involved in the energy supply for the process of amylase and sialic acid release. In particular, the energy supply demanded for the activation of Na+ pump may play a role in the mechanism by which pilocarpine induces the oxygen uptake.     

Induction of Stomatal Closure by Helminthosporium maydis Pathotoxin

Helminthosporium maydis pathotoxin caused a rapid inhibition of photosynthesis in whole leaves of maize having Texas male-sterile cytoplasm but not in leaves having normal cytoplasm. Electron transport, phosphorylation, and proton uptake activities of isolated chloroplast lamellae, from either normal or Texas male-sterile cytoplasm leaves, were unaffected by addition of toxin to the reaction mixture. The toxin was found to have a direct effect on stomatal functioning. Rates of transpiration were inhibited in treated leaves at times slightly preceding the observed effects on photosynthesis. In studies with isolated epidermal peels from Texas male-sterile cytoplasm maize leaves, the toxin inhibited light-induced K⁺ uptake by guard cells. All effects of the toxin on Texas male-sterile cytoplasm maize tissues were found to be similar to the mode of action of abscisic acid.     

Studies on the Metabolism of Aspergilli

Studies were made on the endogenous respiration of Aspergillus sojae K.S. Observing the changes of Kjeldahl-nitrogen in each fraction of the mycelial components, the author concluded that pool amino acids, bound amino acids, protein, nucleic acids and nucleotides covered whole of the nitrogenous reserves available for endogenous respiration in the mycelia. A study was carried out on the effect of preincubation with glucose or amino acids on endogenous respiration. Stimulation of either oxygen uptake, protein breakdown or ammonia formation was observed during respiration of the mycelia incubated with a suitable concentration of azide, 2,4-dinitrophenol, potossium fluoride, monoiodoacetic acid or ethylenediaminetetraacetic acid. Ammonia formation accompanied with endogenous respiration seemed to proceed inversely by the influence of energy yielding reaction.     

NATURE OF THE INHIBITION OF PROTEIN SYNTHESIS BY ETHIONINE AND AMINO ACID UPTAKE IN EARLY SEA URCHIN EMBRYOS

The inhibition of protein synthesis by ethionine reported previously was found to be apparent, and ethionine inhibited only amino acid uptake like other usual amino acids. Even under such strong inhibition of the uptake, the syntheses of protein and DNA remained almost undiminished. The uptake of amino acid mixture by sea urchin embryos in the early cleavage stage was found to be carried out by active transport, since it was temperature-sensitive and was inhibited by 2,4-dinitrophenol. The uptake of an amino acid mixture or of single amino acids, e.g., valine, leucine and phenylalanine, was inhibited nonspecifically by an excess amount of other single amino acids added exogenously. Reflecting the inhibition of amino acid uptake, in vivo incorporation of amino acids into the protein fraction was apparently inhibited by excess amounts of other amino acids. As far as tested, the inhibition seems to be nonspecific and competitive for all amino acid species. The uptakes of leucine and phenylalanine were inhibited mutually by competition, with almost the same Km and Ki.