scholarly journals Isolation of an Obligate Mixotrophic Methanogen That Represents the Major Population in Thermophilic Fixed-Bed Anaerobic Digesters

2020 ◽  
Vol 8 (2) ◽  
pp. 217
Author(s):  
Misa Nagoya ◽  
Atsushi Kouzuma ◽  
Yoshiyuki Ueno ◽  
Kazuya Watanabe
Keyword(s):  
Carbon Dioxide ◽  
Colony Formation ◽  
Culture Media ◽  
Fixed Bed ◽  
Nitrogen Atmosphere ◽  
Anaerobic Digesters ◽  
Solid Media ◽  
Partial Pressures ◽  
Limiting Dilution

Methanothermobacter Met2 is a metagenome-assembled genome (MAG) that encodes a putative mixotrophic methanogen constituting the major populations in thermophilic fixed-bed anaerobic digesters. In order to characterize its physiology, the present work isolated an archaeon (strain Met2-1) that represents Met2-type methanogens by using a combination of enrichments under a nitrogen atmosphere, colony formation on solid media and limiting dilution under high partial pressures of hydrogen. Strain Met2-1 utilizes hydrogen and carbon dioxide for methanogenesis, while the growth is observed only when culture media are additionally supplemented with acetate. It does not grow on acetate in the absence of hydrogen. The results demonstrate that Methanothermobacter sp. strain Met2-1 is a novel methanogen that exhibits obligate mixotrophy.

scholarly journals STUDIES ON THE MODE OF SPREAD OF B. ENTERITIDIS MOUSE TYPHOID INFECTION

1927 ◽  
Vol 46 (6) ◽  
pp. 855-870 ◽  
Author(s):  
Leslie T. Webster ◽  
Caspar Burn
Keyword(s):  
Colony Formation ◽  
Culture Media ◽  
Transformation Process ◽  
Natural Conditions ◽  
The Past ◽  
Working Hypothesis ◽  
Solid Media ◽  
Fluid Media ◽  
At Will

The experiments described in this paper are part of a larger number which we have been carrying out for the past 2 years. Although they have not entirely fulfilled their purpose, which was to explain the so called "mutation," "dissociation," "Umwandlung," "transformation" process, they have served to formulate a helpful working hypothesis. Certain difficulties inherent in this kind of study must be recognized. One is that colony formation is a property associated with growth on solid media and any procedure involving the use of fluid media introduces a change which is relatively uncontrolled. Another is that mucoid and rough colony forms are not the only variant types encountered; at best, they may be considered as being the most frequent. Finally, it is apparent to us that the findings reported in this paper with respect to enteritidis organisms do not correspond with those of other species of organisms, especially of the respiratory group which we have studied (1, b). Possibly, however, they apply generally to the typhoid, paratyphoid-enteritidis species. To summarize, it may be stated that the transformation process in the mouse typhoid enteritidis group is an easily reversible one, controlled in part, at least, by three factors, any of which may conceivably operate under natural conditions: (1) temperature, which, influences the appearance of mucoid forms; (2) fluidity of culture media, which tends to favor rough variants; and (3) bacteriophage, which stimulates the appearance of both variants. Since by manipulating these factors the transformation process may be incited at will in either direction, it is probably not genetic in nature.

Effects of the Gas Phase Composition and Genesis of the Active Sodium Carbonate on Its Reactivity Towards Gaseous Mixture SO2 + NOx

1997 ◽  
Vol 62 (3) ◽  
pp. 387-391
Author(s):  
Květoslava Stejskalová ◽  
Pavel Bach ◽  
Erich Lippert ◽  
Karel Mocek
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Sodium Carbonate ◽  
Flow Reactor ◽  
Fixed Bed ◽  
Gaseous Mixture ◽  
Solid Substance ◽  
Integral Conditions ◽  
Active Sodium ◽  
Partial Pressures

The reactivity of the solid active sodium carbonate towards gaseous mixture SO2 + NOx has been measured in the dependence on oxygen and carbon dioxide contents and on genesis of the solid substance. The fixed bed flow reactor working under integral conditions has been used. It was found that the reactivity of the active sodium carbonate of the 1st generation towards gaseous mixture SO2 + NOx is higher than the reactivity of the active sodium carbonate of the 2nd generation. In the temperature range of 130-180 °C the partial pressures of oxygen and carbon dioxide have no decisive influence on the reactivity of the active sodium carbonate of the 1st generation.

Inspiratory Speech as a Management Option for Spastic Dysphonia

1992 ◽  
Vol 101 (5) ◽  
pp. 375-382 ◽  
Author(s):  
Gordon A. Harrison ◽  
Richard H. Troughear ◽  
Pamela J. Davis ◽  
Alison L. Winkworth
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Voice Quality ◽  
Management Option ◽  
Communication Problems ◽  
Partial Pressures ◽  
The Subject ◽  
And Control ◽  
Laryngeal Resistance

A case study is reported of a subject who has used inspiratory speech (IS) for 6 years as a means of overcoming the communication problems of long-standing adductor spastic dysphonia (ASD). The subject was studied to confirm his use of IS, determine the mechanisms of its production, investigate its effects on ventilatory gas exchange, and confirm that it was perceptually preferable to ASD expiratory speech (ES). Results showed that the production and control of a high laryngeal resistance to airflow were necessary for usable IS. Voice quality was quantitatively and perceptually poor; however, the improved fluency and absence of phonatory spasm made IS the preferred speaking mode for both the listener and the speaker. Transcutaneous measurements of the partial pressures of oxygen and carbon dioxide in the subject's blood were made during extended speaking periods. These measurements indicated that ventilation was unchanged during IS, and that ventilation during ES was similar to the “hyperventilation” state of normal speakers. The reasons for the absence of phonatory spasm during IS are discussed, and the possibility of its use as a noninvasive management option for other ASD sufferers is addressed.

scholarly journals The Active Transport of Oxygen and Carbon Dioxide into the Swim-Bladder of Fish

1966 ◽  
Vol 49 (6) ◽  
pp. 1209-1220 ◽  
Author(s):  
H.J. KUHN ◽  
E. MARTI
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Active Transport ◽  
Bladder Pressure ◽  
Swim Bladder ◽  
Rete Mirabile ◽  
Partial Pressures ◽  
Gas Gland ◽  
Counter Current ◽  
Good Agreement

The active transport of oxygen and carbon dioxide into the swim-bladder of fish is discussed. The rete mirabile is a capillary network which is involved in the gas secretion into the bladder. The rete is regarded as a counter-current multiplier. Lactic acid which is produced in the gas gland generates in the rete single concentrating effects for oxygen and carbon dioxide; i.e., for equal partial pressures the concentrations of the gases in the afferent rete capillaries are higher than those in the efferent ones. The single concentrating effects were calculated from measurements of sea robin blood (Root, 1931). The multiplication of these effects within the rete for different rete lengths and different transport rates was numerically evaluated. The calculated O2 and CO2 pressures in the bladder are in good agreement with the experimental results of Scholander and van Dam (1953). The descent velocities at equilibrium between bladder pressure and hydrostatic pressure are discussed for fishes with different rete lengths.

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