Factors Affecting Triamineoxidease: I. Inhibition of the Enzyme

1945 ◽  
Vol 6d (5) ◽  
pp. 368-379 ◽  
Author(s):  
J. B. Neilands
Keyword(s):  
Hydrogen Sulphide ◽  
Ammonium Hydroxide ◽  
Factors Affecting ◽  
Partial Inhibition ◽  
Trimethylamine Oxide ◽  
Hydrogen Carrier

Ammonium hydroxide and glycogen have little effect on the formation of trimethylamine from trimethylamine oxide by washed cells of bacteria isolated from fish. Indole, skatole and hydrogen sulphide partially inhibit the enzyme. Partial inhibition can also be effected with cyanide and azide. The necessity in this system of a hydrogen carrier other than the dehydrogenase activating the oxidizable substrate is suggested.

scholarly journals Pt-Ni Nanoalloys for H2 Generation from Hydrous Hydrazine

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 930
Author(s):  
Liu Zhou ◽  
Xianjin Luo ◽  
Lixin Xu ◽  
Chao Wan ◽  
Mingfu Ye
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Design Principle ◽  
Chemical Characteristics ◽  
High Hydrogen ◽  
Factors Affecting ◽  
Dehydrogenation Reaction ◽  
High Hydrogen Content ◽  
H2 Generation ◽  
Hydrogen Carrier

Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been welcomed by researchers for the dehydrogenation of hydrous hydrazine recently. Therefore, in this review, we give a summary of Pt nanoalloy catalysts for the dehydrogenation of hydrous hydrazine and briefly introduce the decomposition mechanism of hydrous hydrazine to prove the design principle of the catalyst. The chemical characteristics of hydrous hydrazine and the mechanism of dehydrogenation reaction are briefly introduced. The catalytic activity of hydrous hydrazine on different supports and the factors affecting the selectivity of hydrogen catalyzed by Ni-Pt are analyzed. It is expected to provide a new way for the development of high-activity catalysts for the dehydrogenation of hydrous hydrazine to produce hydrogen.

Relationship between H2S-producing strains of wine yeast and different fermentation conditions

1999 ◽  
Vol 45 (4) ◽  
pp. 343-346 ◽  
Author(s):  
C Tamayo ◽  
J Ubeda ◽  
A Briones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stainless Steel ◽  
Hydrogen Sulphide ◽  
Yeast Strain ◽  
Alcoholic Fermentation ◽  
Wine Yeast ◽  
Fermentation Conditions ◽  
Factors Affecting ◽  
Different Strains ◽  
The Relationship

Hydrogen sulphide formation is a problem in winemaking. One of the factors affecting formation of this unwanted metabolite is the yeast strain responsible for the process. In this experiment wines were made on a laboratory scale with different strains of H2S-producing Saccharomyces cerevisiae. The relationship between H2S production and various fermentation conditions was examined (SO2, methionine, (NH4)2SO4, (NH4)3PO4, steel, and steel-lees). The results show that in fermentations in the presence of stainless steel and lees, H2S formation is high but declines when (NH4)3PO4is added to the must.Key words: H2S formation, wine-yeast, steel-lees, wine-making, alcoholic fermentation.

The Effect of Certain Antibiotics on the Production of Trimethylamine and Hydrogen Sulphide by Bacterial Enzymes

1957 ◽  
Vol 14 (5) ◽  
pp. 771-774 ◽  
Author(s):  
C. H. Castell ◽  
Maxine F. Greenough
Keyword(s):  
Hydrogen Sulphide ◽  
Bacterial Reduction ◽  
Bacterial Enzymes ◽  
Washed Cell ◽  
Trimethylamine Oxide

By the use of the washed cell technique it has been shown that the antibiotics chlortetracycline, oxytetracycline, polycycline and nisin in concentrations from 1 to 50 p.p.m. do not retard the bacterial reduction of trimethylamine oxide to trimethylamine. It has also been shown that chlortetracycline and oxytetracycline do not inhibit the reduction of cysteine to hydrogen sulphide by bacterial enzymes.

MICROBIAL PENTOSANASES: III. SOME FACTORS AFFECTING THE PRODUCTION OF PENTOSANASES BY ASPERGILLUS NIGER AND TRICHODERMA VIRIDE

1959 ◽  
Vol 5 (1) ◽  
pp. 99-107 ◽  
Author(s):  
F. J. Simpson
Keyword(s):  
Aspergillus Niger ◽  
Corn Steep Liquor ◽  
Synthetic Medium ◽  
Trichoderma Viride ◽  
Maximum Yield ◽  
Ammonium Hydroxide ◽  
Water Soluble ◽  
Factors Affecting ◽  
Steep Liquor ◽  
Mesh Sieve

Of a number of carbohydrates tested, holocellulose from wheat straw and L-arabinose were the better substrates for production of pentosanase by Trichoderma viride. D-Xylose did not induce synthesis of the enzyme by the fungus. Production in a synthetic medium was increased by the addition of malt sprouts, distillers' dried solubles, or glutamic acid.Under the same conditions the production of pentosanase by Aspergillus niger was favored by the water-soluble pentosan of wheat flour, holocellulose, and wheat bran. Both D-xylose and L-arabinose induced synthesis of enzyme. In the synthetic medium the addition of yeast extract, corn steep liquor, malt sprouts, or a number of other nitrogenous adjuncts increased the yield of pentosanase. A medium containing 3% bran ground to pass a 20-mesh sieve, 3% corn steep liquor neutralized with ammonium hydroxide, and 1% calcium carbonate was developed for the production of pentosanase by A. niger. Maximum yield was obtained in 60 hours. The pentosanase had an optimum pH of 5.0 and was stable for 30 minutes at 30 °C between pH 4.0 and 5.8. The pentosanase could be precipitated from the culture filtrates with 76% ethanol and when stored as a dry powder at 2 °C was stable for at least 1 year.

The reactions of blowflies to organic sulphur compounds and other materials used in traps

Parasitology ◽  
1950 ◽  
Vol 40 (1-2) ◽  
pp. 187-194 ◽  
Author(s):  
J. B. Cragg ◽  
Beryl A. Thurston
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulphide ◽  
Ammonium Carbonate ◽  
Ammonium Hydroxide ◽  
Field Trapping ◽  
Climatic Conditions ◽  
Sulphur Compounds ◽  
Ethyl Mercaptan ◽  
Organic Sulphur ◽  
Materials Used

1. Seven organic sulphur compounds likely to be produced in the breakdown of cystine have been tested under field conditions as blowfly attractants. Two of them, ethyl mercaptan and dimethyl di-sulphide, when mixed with hydrogen sulphide or carbon dioxide formed powerful attractants for females of the blowflies Lucilia caesar (and L. illustris) and L. sericata.2. In the majority of trials 10 ml. 0·2% ethyl mercaptan mixed with 10 ml. freshly saturated hydrogen sulphide solution was used as the control attractant. As a standard in field-trapping studies this material overcomes many of the disadvantages of meat baits.3. Sodium carbonate, sodium bicarbonate, ammonium hydroxide, ammonium carbonate and indole, at various concentrations, did not activate the organic compounds. Furthermore, when added to the ethyl mercaptan-hydrogen sulphide preparation they did not increase its activity.4. In the present experiments oviposition was rarely induced. When it did occur it was associated with the presence of indole.5. L. caesar responded to attractants placed 2 ft. from the ground as well as to the same materials placed on the ground. Height alone, therefore, was not responsible for the fact that L. caesar did not respond to the attractants when they were placed on sheep.6. The responses of blowflies to chemical attractants was linked with climatic conditions. Thus, under certain conditions Calliphora spp., particularly C. vomitoria, responded to these attractants.7. The results obtained in the present investigation emphasize the attractive nature of sulphur-containing compounds and the possible importance of hydrogen sulphide and carbon dioxide as sensitizing agents of such compounds on sheep.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting
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