Respiratory Regulation in Ephemera Simulans Walker and Hexagenia Limbata (Serville) (Ephemeroptera)

1963 ◽  
Vol 40 (3) ◽  
pp. 455-468
Author(s):  
CLYDE H. ERIKSEN
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
The Body ◽  
Respiratory Regulation ◽  
Wide Range ◽  
Lower Oxygen ◽  
Hexagenia Limbata ◽  
Lower Oxygen Concentration ◽  
Oxygen Concentrations

1. This study shows that Ephemera simulans and Hexagenia limbata are respiratory regulators and how it is that regulation is attained and maintained. 2. Nymphs, 17-24 mm. in length, were acclimated in the laboratory at 13.o° C. for 24 hr. Oxygen consumption experiments employed the ‘closed-bottle’ technique and several modifications. 3. When studied in bottles containing no substrate, both species appeared to be respiratory adjustors. 4. Using ‘optimal substrates’ and a wide range of oxygen concentrations, both species proved to be respiratory regulators. 5. As the oxygen concentration decreased, respiratory regulation was attained by initiating and increasing a flow of water past the body surfaces by the bailer action of beating gills. The volume passed was proportional to the number of gill beats which, in turn, was influenced by the size of the gills. The larger gills of Hexagenia beat at a slower rate to produce the same current as Ephemera and potentially they were capable of producing a significantly greater current and, hence, could regulate to a lower oxygen concentration.

scholarly journals The Function of the Gills of Mayfly Nymphs from Different Habitats

1939 ◽  
Vol 16 (3) ◽  
pp. 363-373 ◽  
Author(s):  
C. A. WINGFIELD
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Content ◽  
The Body ◽  
Gaseous Exchange ◽  
Low Oxygen ◽  
Respiratory Mechanism ◽  
Tracheal Gills ◽  
Cloeon Dipterum ◽  
Gill Function ◽  
Oxygen Concentrations

1. The oxygen consumption of normal and gill-less nymphs of the mayflies Baetis sp., Cloeon dipterum and Ephemera vulgata has been measured at various oxygen concentrations. 2. It has been found that over the complete range of oxygen concentrations studied, the tracheal gills do not aid oxygen consumption in Baetis sp. In Cloeon dipterum, at all oxygen concentrations tested, no gaseous exchange takes place through the gills; at low oxygen concentrations, however, the gills function as an accessory respiratory mechanism in ventilating the respiratory surface of the body and so aid oxygen consumption. In Ephemera Vulgata the gills aid oxygen consumption even at high oxygen concentrations. In this species the gills may function both as true respiratory organs and as a ventilating mechanism. 3. It is shown that the differences in gill function can be related to the oxygen content of the habitat of each species.

Influence of some factors on oxygen uptake of canine cardiac Purkinje fibers

1963 ◽  
Vol 204 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Kalman Greenspan ◽  
Paul F. Cranefield
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Diffusion Limitation ◽  
Purkinje Fibers ◽  
Ambient Oxygen ◽  
Cardiac Purkinje Fibers ◽  
Lower Oxygen ◽  
Wet Weight ◽  
Oxygen Tensions ◽  
Oxygen Concentrations

The rate of oxygen uptake of quiescent Purkinje fibers of the dog's heart was determined using a flow respirometer and oxygen polarography. At ambient oxygen concentrations of 60% or higher the rate of uptake was 0.739 mm3/mg wet weight per hr at 35 C. The temperature coefficient over the range 25–35° was 2.3. The uptake was independent of the ambient oxygen concentration at oxygen concentrations equal to or greater than 60% of an atmosphere. In lower oxygen concentrations the rate of uptake was found to be depressed. The depression of uptake in the lower oxygen tensions is probably the result of diffusion limitation; it may, however, reflect dependence of resting uptake on oxygen concentration.

Morphology controlled deposition of ZnO single micro-nanorods

2019 ◽  
Vol 9 (5) ◽  
pp. 524-528
Author(s):  
Lina Wang ◽  
Ailing Zou ◽  
Jitong Liu ◽  
Jing Wang ◽  
Dan Zhou ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Chemical Vapor ◽  
Hexagonal Wurtzite Structure ◽  
Chemical Vapor Deposition Method ◽  
Oxygen Defect ◽  
Simple Chemical ◽  
Lower Oxygen ◽  
Controlled Deposition ◽  
Extrinsic Feature ◽  
Lower Oxygen Concentration

The ZnO micro-nanorods are controlledly synthesized by a simple chemical vapor deposition method. With different oxygen concentrations the micro-nanorods exhibit different extrinsic feature and length. Under lower oxygen concentration, the micro-nanorods are up to 1670 μm in length which can be easily operated in singlecrystalline. When the oxygen concentration up to 30 sccm, the surface of the sample is smoother. The Raman spectra reveal that ZnO micro-nanorods have an excellent hexagonal wurtzite structure. However, the micronanorods synthesized during lower oxygen concentration exhibit more oxygen defect. The morphology controlling deposition of ZnO mircro-nanorods were realized by adjust the concentration of oxygen, which has great significance for further gas sensor application.

A nitric oxide-sensitive electrode: Requirement of lower oxygen concentration for detecting nitric oxide from the tissue

1996 ◽  
Vol 35 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Yukisato Ishida ◽  
Michio Hashimoto ◽  
Shoju Fukushima ◽  
Sumio Masumura ◽  
Tetsuya Sasaki ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Oxygen Concentration ◽  
Lower Oxygen ◽  
Sensitive Electrode ◽  
Lower Oxygen Concentration

Oxygen consumption of nymphs of Phasganophora capitata (Pictet) (Plecoptera) with respect to body weight and oxygen concentrations

1975 ◽  
Vol 53 (8) ◽  
pp. 1089-1092 ◽  
Author(s):  
N. N. Kapoor ◽  
W. Griffiths
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Dissolved Oxygen ◽  
Metabolic Rate ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
The Body ◽  
Oxygen Concentrations

A closed respirometer was used for the measurement of respiratory rates [Formula: see text] of nymphs of Phasganophora capitata (Pictet). Nymphs were found to be conformers since they reduced their oxygen consumption rate when the level of dissolved oxygen in the water was reduced.No significant correlation (P > 0.05) was observed between oxygen consumption and body weight. The metabolic rate [Formula: see text] of nymphs increased less than the body weight or mass.

Respiratory metabolism of Azotobacter vinelandii cells at oxygen concentrations that initially range from suboptimal to supraoptimal for nitrogenase activity

1991 ◽  
Vol 37 (4) ◽  
pp. 321-325 ◽  
Author(s):  
Jay B. Peterson
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Apparent Affinity ◽  
Lower Oxygen ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

The effects of three low oxygen concentrations on nitrogenase activity, total oxygen uptake, and respiratory parameters (Vmax and Ks(O2) of N2-grown Azotobacter vinelandii were studied in acetylene reduction assays during a 2-h incubation. The cell suspensions were taken from cultures grown at low aeration. Total oxygen uptake was higher with each increment in oxygen concentration. The highest oxygen concentration was initially supraoptimal for nitrogenase activity. The Ks(O2) values, representing the apparent affinity of the respiration system for oxygen, increased during the incubation of cells at the highest oxygen concentration. The Ks(O2) values at the two lower oxygen concentrations decreased and were very similar. A small effect of oxygen on the Vmax was observed. These results show that the metabolism determining the apparent affinity of the system for oxygen responds to the oxygen concentrations. Furthermore, this metabolism did not substantially increase the Ks(O2) unless the oxygen concentration was high enough to inhibit nitrogenase activity, indicating that the two processes may be linked. Key words: Azotobacter, oxygen regulation, nitrogen fixation.

scholarly journals A Fermentor System for Regulating Oxygen at Low Concentrations in Cultures of Saccharomyces cerevisiae

1998 ◽  
Vol 64 (3) ◽  
pp. 1040-1044 ◽  
Author(s):  
Patricia V. Burke ◽  
Kurt E. Kwast ◽  
Frank Everts ◽  
Robert O. Poyton
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Gas Flow ◽  
Cell Mass ◽  
Yeast Cells ◽  
Cellular Respiration ◽  
Low Oxygen ◽  
Expression Of Genes ◽  
Low Concentrations ◽  
Oxygen Concentrations

ABSTRACT The growth of yeast cells to high densities at low, but constant, oxygen concentrations is difficult because the cells themselves respire oxygen; hence, as cell mass increases, so does oxygen consumption. To circumvent this problem, we have designed a system consisting of a computer-controlled gas flow train that adjusts oxygen concentration in the gas flow to match cellular demand. It does this by using a proportional-integral-differential algorithm in conjunction with a three-way valve to mix two gases, adjusting their proportions to maintain the desired oxygen concentration. By modeling yeast cell yields at intermediate to low oxygen concentrations, we have found that cellular respiration declines with oxygen concentration, most likely because of a decrease in the expression of genes for respiratory proteins. These lowered rates of oxygen consumption, together with the gas flow system described here, allow the growth of yeast cells to high densities at low oxygen concentrations. This system can also be used to grow cells at any desired oxygen concentration and for regulated shifts between oxygen concentrations.

scholarly journals On the Function of Haemoglobin in Chironomus

1942 ◽  
Vol 18 (3) ◽  
pp. 197-205
Author(s):  
R. F. EWER
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Oxygen Transport ◽  
Oxygen Concentrations

1. At 17°C. the oxygen consumption of Chironomus larvae shows little diminution when the oxygen concentration in the water decreases from 7.5 c.c. per litre (air saturation) to about 3 c.c. per litre. Below 3 c.c. per litre a further decrease in oxygen concentration causes a falling off in oxygen consumption. 2. At 17°C. the oxygen consumption of Chironomus larvae whose haemoglobin has been converted to carboxyhaemoglobin is as great as that of normal animals from air saturation down to 3 c.c. per litre. Below this point the oxygen consumption is less than that of normal animals. 3. It follows that at 17°C. the haemoglobin of Chironomus larvae from well aerated water does not function in oxygen transport at air saturation, but only at oxygen pressures below 3 c.c. per litre. 4. Some observations of the habitat of the larvae show that they can live in situations where oxygen concentrations of less than 2 c.c. per litre persist for periods of at least 16 consecutive hours. The larvae are also to be found in situations where the oxygen concentration is high.

scholarly journals A Study of the Oxygen Consumption of Five Species of Leech

1956 ◽  
Vol 33 (3) ◽  
pp. 615-626
Author(s):  
K. H. MANN
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Body Surface ◽  
The Body ◽  
The Other ◽  
High Rate ◽  
Eutrophic Lakes ◽  
Stagnant Water ◽  
Low Concentrations

1. The oxygen consumption of five species of leech has been investigated and considered in relation to their ecology. 2. Glossiphonia complanata and Erpobdella octoculata which are most common in, but not confined to, hard and soft water streams respectively, have their oxygen consumption dependent on the concentration of dissolved oxygen, at least in spring and summer. Their oxygen uptake is not affected by acclimatization overnight to a low level of oxygen, but the uptake of Glossiphonia at the higher oxygen concentrations is depressed in winter. 3. Erpobdella testacea has an oxygen consumption which is independent of the oxygen concentration between 6.0 and 3.0 ml./l., provided that the leeches have been acclimatized overnight to the oxygen concentration at which their uptake is measured. Ventilation of the body surface by dorso-ventral undulations appears to be an important factor in the maintenance of a high rate of oxygen uptake at low concentrations. This species is found in reed swamps. 4. Helobdella stagnalis, which is most abundant in stagnant eutrophic lakes, maintains a level of oxygen consumption which is independent of the oxygen concentration between 2.0 and 4.0 ml./l., even without previous acclimatization. 5. Piscicola geometra, which is virtually absent from stagnant water, has a higher rate of oxygen uptake than any of the other species under conditions of air-saturation, and its rate is strictly dependent on the concentration of oxygen in the water.

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