Oxygen Bubbling Research Articles

Kinetic study on the formation of platinum-blue complexes with oxygen.

A kinetic study of Pt-blue complex formation was carried out in a solution containing [Pt (NH3)2 (H2O)2]2+ and uracil under oxygen bubbling, with monitoring by means of an oxygen analyzer and visible spectrometer. The rate of oxygen consumption was first-order with respect to concentration of [Pt (NH3)2 (H2O)2]2+, uracil, or oxygen. A correlation was found between the decrease of oxygen consumption in the solution and the increase of the absorbance at 640 nm, namely formation of the blue complex. The formation mechanism of the blue complex is considered to be 1) first the equilibrium reaction of the coordination of uracil to Pt, 2) next the oxidation of the Pt-uracil complex with oxygen, and 3) finally a follow-up reaction presumably via formation of polynuclear complexes. Eight other blue complexes were formed by the use of N-aromatic base ligands possessing an amide linkage. The oxygen consumption rates of these complexes were found to be large in the case of the ligands which form many structurally isomeric complexes.

Photolysis of poly(3‐buten‐2‐one), poly(4,4‐dimethyl‐1‐penten‐3‐one), and poly(3‐methyl‐3‐buten‐2‐one) in the presence of oxygen

AbstractPhotolysis of poly(3‐buten‐2‐one) (PMVK), poly(4,4‐dimethyl‐1‐penten‐3‐one) (PBVK), and poly(3‐methyl‐3‐buten‐2‐one) (PMIK) were carried out in dioxane under oxygen or nitrogen bubbling. The main chain degradations of PBVK and PMIK were quenched and polymeric peroxides were produced. The heat treatment of the polymer irradiated in the presence of oxygen promoted the degradation. The photodegradation of PMVK was enhanced in the presence of oxygen.

The electron transfer reactivity of cytochrome P-450-CAM. Molecular oxygen dependent multiple turnovers using chemical reductants

Cytochrome P-450, unlike most other cytochrome,s does not function merely as an electron carrier but is also an enzyme capable of catalyzing oxygenation reactions. This heme-containing monooxygenase activates molecular oxygen for insertion of one oxygen atom into organic substrates with concomitant reduction of the other oxygen atom to water. Bacterial P-450, isolated from camphor-grown Pseudomonas putida (P-450-CAM)†, utilizes molecular oxygen and NADH to hydroxylate camphor at the exo-5 position and initiate camphor degradation [1]. Because the hemoprotein itself cannot react directly with NADH, electrons are transferred from NADH to P-450-CAM via first a FAD-containing flavoprotein (putidaredoxin reductase, fp) and then an iron-sulfur protein (putidaredoxin. Pd). t001 Product Formation. a A. As a function of P-450-CAM Concentration P-450-CAM Conc. (μ M) Exo-5-hydroxycamphor formed c (nmol) With Putidaredoxin (3 μ M) 0 0.1 ± 0.01(2) 0.5 23.6 ± 1.0(2) 1.0 49.8 ± 1.5(6) 2.0 97.0 ± 2.5(2) Without Putidaredoxin 0 0.02 ± 0.01(2) 0.5 1.3 ± 0.1(2) 1.0 2.7 ± 0.2(3) 2.0 5.1 ± 0.2(3) B. As a Function of Time Incubation (min) Exo-5-hydroxycamphor formed c (Mol/Mol of P-450-CAM) With Putidaredoxin (3 μ M) 1 28.8(1) 2 49.8 ± 1.5(6) 5 101.7(1) 10 188.7 ± 5.0(2) Without Putidaredoxin 1 1.5 ± 0.1(2) 2 2.7 ± 0.2(3) 5 5.8 ± 0.1(2) 10 9.8 ± 0.3(2) C. Control Experiments Exo-5-hydroxycamphor formed c (nmol) Without Pd d With 5 μ M Pd e 1. No P-450 0.02 ± 0.01(2) 0.01 ± 0.01(2) 2. No NADH 0.01 ± 0.01(2) 0.01 ± 0.01(2) No PMS 0.02 ± 0.01(3) 0.01 ± 0.01(3) 4. Boiled P-450 f 0.03 ± 0.02(2) - 5. Myoglobin (no P-450) g None - bTwo minute incubations. a Incubations were done using optimized conditions unless otherwise indicated. Optimized conditions; 1 μ M P-450-CAM, 600 μ M d-camphor, 3 m M NADH, and 50 μ M PMS, in 20 m M phosphate buffer (pH 7.40, and 100 m M KCI), 2 ml total volume, with gentle oxygen bubbling. In the presence of Pd (3–5 μ M), 5 m M NADH was used. c The number in parentheses is the number of trials of a particular experiment. d Ten minute incubations without oxygen bubbling using optimized conditions except as follows: 1.6 m M NADH, 250 μ M PMS. e Same conditions as described in footnote d, plus oxygen bubbling. f P-450-CAM was boiled for 10 minutes prior to use. g 1 μ M myoglobin. of the inhibition and oxygen bubbling studies support the hypothesis that hydroxylation by the NADH/PMS/P-450-CAM system occurs by an oxygen-dependent enzymatic pathway. The role of the PMS in the system appears to be as a mediator of electrons from NADH to P-450. This system provides the first protocol for achieving molecular oxygen dependent multiple turnovers of P-450 in the absence of the fully reconstituted three protein system.

Respiration of carp under anesthesia induced by mixed bubbling of carbon dioxide and oxygen.

Anesthetization of fish by mixed bubbling into the ambient water of carbon dioxide and oxygen is being tried as a method of live transport. To get fundamental information on fish under anesthesia, respiratory parameters were measured with carp before, during and after anesthesia induced by 1:1 mixed bubbling of carbon dioxide and oxygen. During the anesthesia, oxygen content and oxygen saturation of the arterial blood was maintained at levels higher than or equal to the pre-anesthetic ones owing to very high PO2 accompanied with elevated Ht and Hb in the blood, in spite of enormously high PCO2 which ought to reduce the oxygen affinity of the blood. Gill ventilation was also maintained at the pre-anesthetic level due to increased frequency of respiration, notwithstanding its reduced stroke volume. Oxygen consumption was reduced to one-half its pre-anesthetic level, accompanied with a sharp drop of oxygen utilization at the gills.

Thin-layer flow cell system for ascorbate enzyme electrode.

A thin-layer flow cell system for the determination of l-ascorbic acid by an ascorbate electrode was constructed and several components of this system were investigated. The most preferable conditions for optimum operation of the system were as follows: injection volume 150 μ1, delay coil length 60 cm, flow rate 1 ml/min, temperature 20°C, cell spacer thickness 0.2 mm. The linear response region was 0.2-3.0 mm and 0.02-0.5 mm (original l-ascorbic acid concentration) in the cases of pure oxygen and atmospheric oxygen bubbling, respectively. The relative standard variation at 1.5 mm l-ascorbic acid was 3.1 % for 20 successive assays. The measuring time was 2–3 min for each of these assays.

Influence of crystallographic properties on antimony electrode potential—III. Oriented monocrystalline material

Crystallographically oriented monocrystalline antimony electrodes representing close-packed crystallographic planes have been studied in HClSbOCl solutions at pH 1.9. The electrode potentials were found to stabilize in less than 1 min. They then remained stable at that level to within 1 mV for more than 100 h of continuous use unless a surface defect existed or developed. The potentials of the different electrodes were reproducible to within 1 mV and repeatable to within 0.2mV. The typical short-term potential variations were 0.1 mV for long periods of time and no stirring effect was noted during the first 100h of use. All electrodes responded reproducibly to oxygen and nitrogen bubbling and to temperature changes in the solution. The maximum long-term potential drift encountered after the first 100 h period of relative potential stability was − 0.8mV/day during a total of 800 h use. Sem studies of the surfaces of used electrodes showed only minor corrosion and no signs of a covering surface (oxide) structure. The surfaces also appeared less corroded for electrodes with more close-packed surfaces. These electrodes also possessed the most negative potentials.

Decoloration and degradation of an anthraquinone dye aqueous solution in flow system using an electron accelerator

A study on the decoloration and degradation of a commercial anthraquinone dye (Acid Blue 40) was carried out by electron-beam irradiation. Experiments were done in a flow system using a five-stage, dual-tube bubbling column reactor. The oxygen contents of the gas bubbled into the inner tubes of the columns were varied from 0 to 100%. The inlet dye concentration, the solution feed rate and the dose rate were also varied from 50 to 100 ppm, 1.5 to 101/min and 0.1 to 0.15 Mrad/s, respectively. The degree of decoloration and degradation of aromatic rings increased with the oxygen content and became close to those for pure oxygen bubbling system at about 25% of oxygen content. The amount of degraded aromatic rings was proportional to that of consumed oxygen. The rate expression of the decoloration and degradation of the dye and the oxygen consumption were derived according to a reaction scheme.

Purification and characterization of a sulfhydryl-dependent protease from Rhodnius prolixus midgut

The characterization and partial purification of one protease from Rhodnius prolixus midgut are described. Enzyme preparations show a high degree of instability under several conditions, such as handling, freezing, and thawing, and at 4°C. This spontaneous inactivation of either crude or purified enzyme is completely protected by 10 mM tetrathionate. Sulfhydryl compounds such as β-mercaptoethanol, dithiothreitol, cysteine, thioglycolic acid, and reduced glutathione are able to activate the enzyme, whereas iodoacetate, mercuric chloride, p -aminophenylmercuric chloride, tetrathionate, and 5,5-dithiobis(2-nitrobenzoic acid) inhibit the enzyme. Partial inhibition was obtained by hydrogen perioxide, oxygen bubbling, and performic acid. Besides casein, the enzyme hydrolyzed benzoyl- l -tyrosine ethyl ester (BTEE), but showed no esterolytic activity upon p -tosyl- l -arginine methyl ester and benzoyl- l -arginine ethyl ester. Purifications of 210- and 187-fold with yields of 80 and 71% respectively, were obtained for the caseinolytic and esterolytic activities by using a Sepharose-mercurial column as a thiol-group affinity adsorbent. The molecular weight was estimated as 21,500 by gel filtration. α-Chymotrypsin and the midgut enzyme show similar abilities to hydrolyze casein, however, the midgut protease hydrolyzes casein 2.7-fold faster than trypsin and about 3-fold slower than pepsin. Soybean trypsin inhibitor, black-eyed pea chymotrypsin inhibitor, tosyl- l -lysine chloromethyl ketone, and tosyl-amide-phenylethyl chloromethyl ketone do not inhibit the protease activity, whereas, pepstatin showed a 100% inhibitory effect at an inhibitor/enzyme molar ratio of 0.36. Midgut protease and α-chymotrypsin showed similar K m values for BTEE (1.06 and 1.15 m ×10 −4 , respectively), however, the former showed a 9-fold lower catalytic efficiency ( K cat / K m ). Dialysis did not affect the enzyme, whereas Cu 2+ , Pb 2+ , and Hg 2+ showed an inhibitory effect; a slight activation was obtained in the presence of Ca 2+ .

ＳＣＰ廃液 Ｖ 紫外線処理における照射効率の向上

In the previous reports, it was found that the color of pulping spent liquor of various kinds could be removed by the aid of irradiation with high pressure UV-lamp, though the exposure time was rather long. In continuing this work, an attempt was made to shorten the irradiation time onto NSSCP spent liquor containing 250 ppm of organic materials, because color removal of the liquor has been known for a difficult problem remained unsolved. Several factors such as oxygen- or air-bubbling, pH and temperature that would improve the photochemical efficiency were examined. Among these, oxygen bubbling was found to be most effective. On irradiation, the rate of color removal was accelerated in both alkaline and acidic media, and increased with increasing of temperature. As a result, the fastest color removal of 90 per cent and COD decrease of 40 per cent were accomplished under the irradiation condition at pH 12 and 60°C with oxygen bubbling for about 2 hr as shown in Fig. 6. In another experiments, various additives were also examined to find better efficiency under the irradiation condition at room temperature for 1.5 hr in alkaline media and for 2.5 hr in acidic media. Addition of 25 ppm of rose bengal and periodate at both pH 12 and 5, and acetyl acetone and hydrogen peroxide at pH 5 could achieve color removal of about 90 per cent as shown in Table 1. Remarkable efficiencies were also recorded in case of less amount addition of rose bengal at pH 12.

Mechanism of Inactivation of Bacteriophage J1 by Glutathione

Mechanism of inactivation of a double-stranded DNA phage, phage Jl of Lactobacillus casei, by reduced form of glutathione (GSH) was studied. Air (oxygen) bubbling, oxidizing agents and transition metal ions enhanced the rate of inactivation of the phage by GSH. Partial oxidation of GSH resulted in a more rapid rate of inactivation. In contrast, nitrogen bubbling, reducing agents, chelating agents and radical scavengers prevented the inactivation. Fully oxidized GSH had no phagocidal effect. These results indicate that the inactivating effect of GSH requires the presence of molecular oxygen and is caused by free radical involved in the mechanism of GSH oxidation. The target of GSH in the phage particle was not the tail protein but DNA. GSH reacted with phage DNA and caused single-strand scissions in the DNA, as exhibited by alkaline sucrose gradient centrifugation; thus inactivating phage.

Mechanism of Inactivation of Bacteriophage J1 by Glutathione

Mechanism of inactivation of a double-stranded DNA phage, phage Jl of Lactobacillus casei, by reduced form of glutathione (GSH) was studied.Air (oxygen) bubbling, oxidizing agents and transition metal ions enhanced the rate of inactivation of the phage by GSH. Partial oxidation of GSH resulted in a more rapid rate of inactivation. In contrast, nitrogen bubbling, reducing agents, chelating agents and radical scavengers prevented the inactivation. Fully oxidized GSH had no phagocidal effect. These results indicate that the inactivating effect of GSH requires the presence of molecular oxygen and is caused by free radical involved in the mechanism of GSH oxidation.The target of GSH in the phage particle was not the tail protein but DNA. GSH reacted with phage DNA and caused single-strand scissions in the DNA, as exhibited by alkaline sucrose gradient centrifugation; thus inactivating phage.

Identification of Trihydroxy-Octadecenoates Derived from UV Irradiated or Autoxidized Sesame Oil and Methyl Linoleate and Mechanism of Their Formation

Four trihy droxy-octadecenoates (T) were separated from sesame oil (SO) and methyl linoleate (ML) subjected to UV irradiation or oxygen bubbling by column and thin-layer chromatography. From the results of IR, NMR, MS and elemental analysis, two out of the four were identified as methyl 9, 10, 13-trihydroxy-11 (trans) -octadecenoates. The remainder methyl 9, 12, 13-trihydroxy-14 (trans) -octadecenoates (in the case of SO, after methylation), and the two compounds in each group were estimated to be stereoisomeric one another. In addition, the mechanism of their formation was clarified using ML and it proved that T were produced from ML through such intermediates as methyl linoleate hydroperoxides (H) and methyl hydroperoxy-epoxy-octadecenoates (E). T was quite stable against UV light and prolonged autoxidation.

Studies on the Oxidation Mechanism of Vitamin E

α-Tocopherol model compound, 2,2,5,7,8-pentamethyl-6-hydroxychroman was oxidized under oxygen bubbling. Four oxidation products of 2-(γ,γ-dimethylallyl)-3,5,6-trimethyl-1,4-benzoquinone (B), 2,2,7,8-tetramethyl-5-formyl-6-hydroxychroman (C), trimer (D) and tocopherylethane (G) were identified, and spirodimer (E) was tentatively identified by TLC. Two of them, (B) and (C) have not been obtained in the oxidation of α-tocopherol model compound with p-quinone, alkaline ferricyanide and other compounds as oxidizing agent. A scheme of oxidation mechanism of α-tocopherol model compound was also proposed.

Correlation of Alteration in Chromosome Replication Sequence with Cell Lethality

This study is a comparison of two methods of analyzing DNA replication in bacteria. Oxygen sensitization of DNA replication to X-irradiation was studied by (1) analysis of the replication sequence (qualitative measurement) and (2) assay of the amount of incorporation of radioactive precursor into the DNA fraction (quantitative analysis). An alteration in the sequential replication of the bacterial chromosome was observed within 10 minutes of postirradiation incubation at a colony survival of 65 to 75%. A 7500-R dose of X-rays with nitrogen bubbling induced the same extent of alteration in replication sequence as a 2000-R dose with oxygen bubbling, resulting in a dose-reduction factor of 3.75. As a result of radiation doses allowing 70% survival, a clear and immediate alteration of the replication sequence was evident. In contrast, only a slight delayed effect on DNA synthesis was reflected when the rate of radioactive thymine uptake was measured. These results indicate that analysis of sequential DNA repl...

STUDIES ON BACILLUS WELCHII WITH SPECIAL REFERENCE TO GAS GANGRENE

1. Spores of the Bacillus welchii group of bacteria were found on 100 per cent of the uniforms of Belgian soldiers who had come directly from the trenches, and in the meshes of all the samples examined of the new cloth from which the uniforms were made. 2. In fifteen out of twenty fresh war wounds members of this group of bacteria were found. Of the fifteen patients, only three later developed gas gangrene. Once the spores of Bacillus welchii have been carried into a wound the deep-lying lacerated muscle tissue appears to be the most important factor in the onset of gas gangrene. 3. Bacillus welchii is able to grow and produce gas in broth containing up to 40 per cent saccharose. Some strains were able to multiply and produce gas in 50 per cent saccharose broth; but none of those examined were able to grow when the concentration of the sugar reached 60 per cent. 4. The bubbling of pure oxygen through milk or dextrose broth cultures of Bacillus welchii has a definite depressor action on the production of gas. This does not appear to be-due to a reduced number of organisms in the culture.