THIORHODACEAE: I. THE EFFECTS OF SODIUM THIOGLYCOLATE ON THE PHOTOSYNTHETIC AND DARK METABOLISM OF PURPLE SULPHUR BACTERIA

1958 ◽  
Vol 4 (5) ◽  
pp. 425-433 ◽  
Author(s):  
John J. Taylor
Keyword(s):  
Carbon Dioxide ◽  
Resting Cells ◽  
Sulphur Compounds ◽  
Experimental Conditions ◽  
Organic Sulphur ◽  
Hydrogen Donors ◽  
Sulphur Bacteria ◽  
Pure Cultures ◽  
Dark Metabolism ◽  
Fixation Of Carbon Dioxide

Twenty-two pure cultures of purple sulphur bacteria were investigated for their ability to utilize organic sulphur compounds as hydrogen donors during photosynthesis. Of the 12 compounds tested, only sodium thioglycolate sustained growth of the organisms in the light.Carbon dioxide fixation by illuminated resting cells in the presence of endogenous sulphur or exogenous thiosulphate was inhibited by thioglycolate in proportion to its concentration. The fixation of carbon dioxide by illuminated sulphur-free resting cells harvested from thioglycolate media increased with the thioglycolate concentration to about 0.04 M, but was proportionally inhibited by higher concentrations.Non-illuminated suspensions of resting cells in the presence of endogenous sulphur or exogenous thiosulphate also assimilated carbon dioxide when thioglycolate was added. Inhibition of fixation appeared similar to that occurring in the light. Thioglycolate disappeared from the suspensions in proportion to the amount of bicarbonate assimilated. Thioglycolate-grown cells did not fix significant amounts of carbon dioxide under similar experimental conditions. Growth of the organisms was never demonstrated in non-illuminated thioglycolate media.

The sulphur bacteria: concluding remarks

1982 ◽  
Vol 298 (1093) ◽  
pp. 601-602 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Transport Systems ◽  
Current Status ◽  
Oxidation Reactions ◽  
Sulphur Compounds ◽  
Human Environment ◽  
Anoxic Environments ◽  
Key Points ◽  
Oxidation Of Organic Compounds ◽  
Sulphur Bacteria

The superb collection of papers presented to this symposium has taken us on a remarkably comprehensive tour of the microbiology, biochemistry, biogeochemistry and environmental role of the sulphur bacteria. I think the contributors have brought us up to date with the current status of knowledge and understanding of these bacteria, their importance in the sulphur cycle, and their impact on the human environment. I do not wish to recapitulate the information presented, other than to single out some key points. Prodigious advances have been made in the microbiological elucidation of sulphate reduction. Organisms are now known (thanks largely to the recent work of Norbert Pfennig and his colleagues and the biochemical studies of Rudolph Thauer’s group) that can couple the reduction of sulphate to the oxidation of organic compounds from the level of hexose sugar completely to carbon dioxide. It has also be shown that diverse oxidized sulphur compounds (sulphite, thiosulphate, polythionates and elemental sulphur) can all be reduced to sulphide. Thus organisms in anoxic environments can convert carbon and sulphur completely to carbon dioxide and sulphide: acetate and sulphur can no longer be regarded as ‘end-products’ of metabolism in anaerobic environments. Similarly the oxidative mechanisms of the chemolithotrophs and photolithotrophs seem at last to be close to complete understanding in terms of enzymes catalysing oxidation reactions and the electron transport systems linked to them.

The reactions of Lucilia sericata (Mg.) to various substances placed on sheep

Parasitology ◽  
1950 ◽  
Vol 40 (1-2) ◽  
pp. 179-186 ◽  
Author(s):  
J. B. Cragg
Keyword(s):  
Carbon Dioxide ◽  
Ammonium Carbonate ◽  
Lucilia Sericata ◽  
Sulphur Compounds ◽  
Negative Results ◽  
Dimethyl Disulphide ◽  
Organic Sulphur ◽  
Cysteine Hydrochloride ◽  
Bacterial Decomposition ◽  
Ammonium Compounds

1. The reactions, under field conditions, of Lucilia sericata (Mg.) to various substances placed on sheep are described.2. Attempts to produce either attraction or oviposition by placing cystine or cysteine hydrochloride in the living fleece gave negative results.3. Several organic sulphur compounds (see Table 1) of a type which might arise from the breakdown of cystine have been tested. All showed some power of attraction for L. sericata. Ethyl mercaptan and dimethyl disulphide were the most powerful as attractants, but none of these substances was able to induce oviposition.4. Tests with ammonium compounds and carbon dioxide have shown that, at the concentrations used, ammonia acted as an attractant. For oviposition to occur carbon dioxide had to be present.5. Hydrogen sulphide was detected as a constituent of the fleece atmosphere of certain sheep. This substance, whilst having no attractive powers when used alone on sheep, increased the attractiveness of organic sulphur compounds.6. Comparative tests with.ammonium carbonate-indole and ammonium carbonate-ethyl mer-captan mixtures have shown marked variations in the relative powers of these preparations to induce oviposition.7. A distinction is drawn between stimuli which attract L. sericata to sheep and those which induce oviposition. Ammonia and various organic sulphur compounds enhanced attraction, but both ammonia and carbon dioxide were necessary for oviposition. It is suggested that some of these materials may be produced under natural conditions from the break-down of fleece keratin or by the bacterial decomposition of sweat and similar products in the fleece.

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.

Microbial efficiency in a meromictic reservoir

2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Grażyna Mazurkiewicz-Boroń ◽  
Teresa Bednarz ◽  
Elżbieta Wilk-Woźniak
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Release Rate ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Metabolic Efficiency ◽  
Sulphur Compounds ◽  
Carbon Dioxide Release ◽  
Microbial Efficiency ◽  
Ion Contents

Microbial efficiency in a meromictic reservoirIndices of microbial efficiency (expressed as oxygen consumption and carbon dioxide release) were determined in the water column of the meromictic Piaseczno Reservoir (in an opencast sulphur mine), which is rich in sulphur compounds. Phytoplankton abundances were low in both the mixolimnion (up to 15 m depth) and monimolimnion (below 15 m depth). In summer and winter, carbon dioxide release was 3-fold and 5-fold higher, respectively, in the monimolimnion than in the mixolimnion. Laboratory enrichments of the sulphur substrate of the water resulted in a decrease in oxygen consumption rate of by about 42% in mixolimnion samples, and in the carbon dioxide release rate by about 69% in monimolimnion samples. Water temperature, pH and bivalent ion contents were of major importance in shaping the microbial metabolic efficiency in the mixolimnion, whilst in the monimolimnion these relationships were not evident.

Atom Condensed Fukui Function for Condensed Phases and Biological Systems and Its Application to Enzymatic Fixation of Carbon Dioxide

2019 ◽  
Author(s):  
Javier Oller ◽  
David A. Sáez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Molecular System ◽  
Chemical Reactivity ◽  
Nucleophilic Attack ◽  
Stable Conformation ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Dynamics Simulations ◽  
Fixation Of Carbon Dioxide

<div><div><div><p>Local reactivity descriptors such as atom condensed Fukui functions are promising computational tools to study chemical reactivity at specific sites within a molecule. Their applications have been mainly focused on isolated molecules in their most stable conformation without considering the effects of the surroundings. Here, we propose to combine QM/MM Born-Oppenheimer molecular dynamics simulations to obtain the microstates (configurations) of a molecular system using different representations of the molecular environment and calculate Boltzmann weighted atom condensed local reac- tivity descriptors based on conceptual DFT. Our approach takes the conformational fluctuations of the molecular system and the polarization of its electron density by the environment into account allowing us to analyze the effect of changes in the molecular environment on reactivity. In this contribution, we apply the method mentioned above to the catalytic fixation of carbon dioxide by crotonyl-CoA carboxylase/reductase and study if the enzyme alters the reactivity of its substrate compared to an aqueous solution. Our main result is that the protein en- vironment activates the substrate by the elimination of solute-solvent hydrogen bonds from aqueous solution in the two elementary steps of the reaction mechanism: the nucleophilic attack of a hydride anion from NADPH on the α, β unsaturated thioester and the electrophilic attack of carbon dioxide on the formed enolate species.</p></div></div></div>

scholarly journals MECHANISM OF FIXATION OF CARBON DIOXIDE IN THE KREBS CYCLE

1941 ◽  
Vol 139 (1) ◽  
pp. 483-484
Author(s):  
H.G. Wood ◽  
C.H. Werkman ◽  
Allan Hemingway ◽  
A.O. Nier
Keyword(s):  
Carbon Dioxide ◽  
Krebs Cycle ◽  
Fixation Of Carbon Dioxide

scholarly journals THE FIXATION OF CARBON DIOXIDE IN A PLANT TRICARBOXYLIC ACID SYSTEM

1947 ◽  
Vol 171 (1) ◽  
pp. 445-446 ◽  
Author(s):  
Birgit Vennesland ◽  
Joseph Ceithaml ◽  
Miriam C. Gollub
Keyword(s):  
Carbon Dioxide ◽  
Tricarboxylic Acid ◽  
Acid System ◽  
Fixation Of Carbon Dioxide
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