The Function of Haemoglobin in Chironomus Plumosus Under Natural Conditions

1950 ◽  
Vol 27 (1) ◽  
pp. 73-95
Author(s):  
BARBARA M. WALSHE
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Transport ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Filter Feeding ◽  
Chironomus Plumosus ◽  
Show Evidence ◽  
Water Drops ◽  
Rate Of Recovery ◽  
Oxygen Concentrations

1. The behaviour of final-instar larvae of Chironomus plumosus housed in U-shaped glass tubes was observed at various concentrations of dissolved oxygen and carbon dioxide. 2. Respiratory behaviour, consisting of intermittent irrigation of the tube, alternates with periods of filter-feeding or complete immobility. In well-aerated water about 50% of the time is occupied by respiratory behaviour, 35% by filter-feeding and the remainder by periods of rest. As the oxygen concentration in the water drops, progressively less time is occupied by filter-feeding and immobility and more by respiratory irrigation. Below 10% air saturation of the water larvae no longer feed. When placed in completely anaerobic conditions larvae at first irrigate intermittently but subsequently relapse into immobility. 3. During respiratory behaviour the amount of irrigation and the length of pauses between periods of irrigation change at different oxygen and carbon dioxide contents of the water in such a way as to suggest that the respiratory irrigation is controlled by internal pH changes in the larvae. 4. A spectroscopic examination of the haemoglobin in living larvae showed that the blood pigment holds an approximately 9-min. store of oxygen for the resting animal. In addition to this it acts in the transport of oxygen from the tube water to the larval tissues when the larva pauses between periods of irrigation. It thus decreases the amount of anaerobiosis to be endured during short periods of inactivity. Nevertheless, larvae without a functional haemoglobin (i.e. with carboxyhaemoglobin) still continue to pause during their respiratory behaviour, and the pauses are not strikingly curtailed in length. 5. At very low oxygen concentrations (7.5-9.0% air saturation), when the larva irrigates the tube almost unceasingly, the haemoglobin remains in a state of partial oxygenation, during which time it is functioning continuously in oxygen transport. At these oxygen concentrations larvae with carboxyhaemoglobin do not show respiratory activity but assume the immobility characteristic of anaerobic conditions. 6. Larvae with carboxyhaemoglobin tend to be less active than normal animals, except in well-aerated water, the decreased activity being largely due to a reduction in the amount of filter-feeding. Such larvae have not been observed to filter-feed at oxygen concentrations below 26% air saturation, whereas the limiting concentration for normal larvae is 10%. 7. After a prolonged period of anaerobiosis larvae show evidence of the repayment of an oxygen debt by prolonged irrigation of the tube when oxygen is once more available. A return to a normal irrigation rate is rapid and is usually followed by a period of filter-feeding The rate of recovery is proportional to the oxygen content of the incoming water, but normal larvae can recover even in water only 7 % air saturated. Larvae with carboxyhaemoglobin, on the other hand, show a considerably retarded rate of recovery from anaerobic conditions, and cannot recover in water less than 15% air saturated. 8. The main significance of haemoglobin in the life of a full-grown Chironomus larva would thus seem to be threefold: (a) haemoglobin enables the larva to maintain the active process of filter-feeding when relatively little oxygen is present; (b) it acts in oxygen transport at very low oxygen concentrations, thereby enabling continued respiratory irrigation; and (c) it greatly increases the rate of recovery from periods of oxygen lack, making such recovery possible even under adverse respiratory conditions.

scholarly journals Studies of Dormancy in the Seeds of Subterranean Clover (Trifolium Subterraneum L.)

1969 ◽  
Vol 22 (2) ◽  
pp. 279 ◽  
Author(s):  
LAT Ballard ◽  
AE Grant Lipp
Keyword(s):  
Carbon Dioxide ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Second Phase ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Breaking Dormancy ◽  
Low Concentrations ◽  
Stimulation Of ◽  
Oxygen Concentrations

When imbibed dormant subterranean clover seeds were exposed to low concentrations of oxygen for up to 6 days, and then transferred to either air or 100% oxygen atmospheres, germination was markedly increased above that of seeds held only in air. Stimulation of germination was similar whether the atmosphere of the second phase was air or 100% oxygen; it was maximal when that of the first phase contained no oxygen, and became insignificant above concentrations in the region of 5% oxygen. The additional germination was roughly proportional to the duration of exposure to low oxygen concentrations, and the effects of two separated exposures to low oxygen were additive. These effects could be produced only in those dormant samples whose seeds or embryos could also be made germinable by exposure to 2�5% carbon dioxide. At higher temperatures, anaerobic conditions were less effective in breaking dormancy, paralleling the reduced efficacy of carbon dioxide at these temperatures.

scholarly journals Thermodynamic modeling of solid fuel gasification in mixtures of oxygen and carbon dioxide

2021 ◽  
Vol 2119 (1) ◽  
pp. 012101
Author(s):  
I G Donskoy
Keyword(s):  
Carbon Dioxide ◽  
Thermodynamic Modeling ◽  
Solid Fuel ◽  
Carbon Capture ◽  
Power Plants ◽  
Thermal Power ◽  
Carbon Capture And Storage ◽  
Low Oxygen ◽  
Fuel Conversion ◽  
Oxygen Concentrations

Abstract One of the main problems in the use of solid fuels is inevitable formation of significant amounts of carbon dioxide. The prospects for reducing CO2 emissions (carbon capture and storage, CCS) are opening up with the use of new coal technologies, such as thermal power plants with integrated gasification (IGCC) and transition to oxygen-enriched combustion (oxyfuel). In order to study the efficiency of solid fuel conversion processes using carbon dioxide, thermodynamic modeling was carried out. Results show that difference between efficiency of fuel conversion in O2/N2 and O2/CO2 mixtures increases with an increase in the volatile content and a decrease in the carbon content. The effect of using CO2 as a gasification agent depends on the oxygen concentration: at low oxygen concentrations, the process temperature turns out to be low due to dilution; at high oxygen concentrations, the CO2 concentration is not high enough for efficient carbon conversion.

Constriction of Human Umbilical Vein Under Aerobic and Anaerobic Conditions

1972 ◽  
Vol 50 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Xina Nair ◽  
Donald C. Dyer
Keyword(s):  
Carbon Dioxide ◽  
Umbilical Vein ◽  
Sodium Cyanide ◽  
Metabolic Inhibitors ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Human Umbilical Vein ◽  
Carbon Dioxide Atmosphere ◽  
Average Maximum ◽  
Aerobic And Anaerobic

In the presence of metabolic inhibitors, the responses to serotonin of helically cut strips of human umbilical vein in Krebs–Henseleit solution at 37 °C were recorded isotonically. The tissues contracted to serotonin in a 95% nitrogen – 5% carbon dioxide atmosphere and in the presence of sodium cyanide (NaCN, 10−3M) and 2,4-dinitrophenol (DNP, 10−3M). The results indicate that human umbilical vein is capable of responding quite well to serotonin at very low oxygen levels and in the presence of sodium cyanide. The average maximum contractions to serotonin in the presence of NaCN and in the 95% nitrogen – 5% carbon dioxide atmosphere were, respectively, 91% and 88% of control. The contractile responses to serotonin were quite inhibited in the presence of 2,4-dinitrophenol. The combination of NaCN plus DNP did not inhibit the contractions to serotonin over that inhibited by DNP alone.

scholarly journals Effect of. Oxygen and Carbon Dioxide on the Mitochondria of Sclerotium Rolfsh

1969 ◽  
Vol 22 (4) ◽  
pp. 1061
Author(s):  
NG Nair ◽  
NH White ◽  
DM Griffin ◽  
Suzanne Blair§
Keyword(s):  
Carbon Dioxide ◽  
Sclerotium Rolfsii ◽  
Yeast Cells ◽  
Low Oxygen ◽  
High Carbon ◽  
Anaerobic Conditions ◽  
External Stresses ◽  
Carbon Dioxide Levels ◽  
Effect Of Oxygen ◽  
High Carbon Dioxide

The number of mitochondria apparently vary with the energy requirements of the cell (see Rouiller 1960). Although swelling and multiplication of mitochondria have been observed to occur in cells, a quantitative analysis of these changes has not been recorded. Matile and Bahr (1968) have recently provided electron micro-scopic evidence of the heterogeneity of density, mass, and volume of the mitochon-drial population in respiring baker's yeast. There are reports in the literature of the complete absence of mitochondria in yeast cells growing under anaerobic conditions (see Marchant and Smith 1968). Griffin and Nair (1968) demonstrated that the growth of Sclerotium rolfsii was inhibited by concentrations of oxygen below 4% and by concentrations of carbon dioxide above 0�03 %. It was, therefore, thought worthwhile to study the changes in mitochondria of this fungus when the cells are subjected to external stresses of low oxygen and high carbon dioxide levels.

Negative arterial-mixed expired PC02 gradient during acute and chronic hypercapnia

1975 ◽  
Vol 38 (3) ◽  
pp. 382-388 ◽  
Author(s):  
D. B. Jennings ◽  
C. C. Chen
Keyword(s):  
Carbon Dioxide ◽  
Dead Space ◽  
Carbon Dioxide Tension ◽  
Passive Diffusion ◽  
Conscious Dogs ◽  
Low Oxygen ◽  
Physiological Dead Space ◽  
Oxygen Concentrations

In resting conscious dogs physiological dead space was calculated using the Bohr equation and measurements of arterial and mixed expired carbon dioxide tension. Whenever dogs inhaled carbon dioxide mixtures (5–10%) that had normal or low oxygen concentrations, the calculated dead space became negative. This paradox was based on the fact that the mixed expired carbon dioxide tension in resting hypercapnic dogs. Under these circumstances carbon dioxide was produced from the lung as measured by gas analyses and blood analyses. By the lung as measured by gas analyses and blood analyses. By reasoning this implies that “alveolar” carbon dioxide tension was higher than pulmonary venous carbon dioxide tension. The negative carbon dioxide gradient persisted at 14 days of chronic hypercapnia and reverted to normal within 10 min of breathing air after chronic hypercapnia. These findings suggest that the exchange of carbon dioxide in the lung cannot be explained solely on the basis of passive diffusion.

scholarly journals Oxygen and Carbon Dioxide Regulation of Toxic Shock Syndrome Toxin 1 Production by Staphylococcus aureus MN8

2000 ◽  
Vol 38 (5) ◽  
pp. 1797-1803 ◽  
Author(s):  
Jeremy M. Yarwood ◽  
Patrick M. Schlievert
Keyword(s):  
Thin Film ◽  
Carbon Dioxide ◽  
Staphylococcus Aureus ◽  
Toxic Shock Syndrome ◽  
Toxin Production ◽  
Toxic Shock ◽  
Anaerobic Conditions ◽  
Batch Cultures ◽  
Toxic Shock Syndrome Toxin ◽  
Oxygen Concentrations

The production of toxic shock syndrome toxin 1 (TSST-1) byStaphylococcus aureus MN8 exposed to a range of oxygen concentrations (0 to 21% [vol/vol]) was examined in batch and thin-film cultures. The response of S. aureus to this range of oxygen concentrations was studied in the absence and in the presence of 7% (vol/vol) carbon dioxide. In the absence of carbon dioxide, TSST-1 production in batch cultures increased from negligible levels in the presence of oxygen concentrations of 1% or less to 500 ng/ml in the presence of 2% oxygen and then decreased to 70 ng/ml or less in the presence of oxygen concentrations of 6% and higher. In the presence of carbon dioxide, however, toxin production increased from negligible levels in the presence of 1% oxygen to 1,900 ng/ml in the presence of 21% oxygen. In thin-film cultures, TSST-1 production increased from nearly undetectable levels under anaerobic conditions to 1 and 10 μg/ml under 21% oxygen in the absence and presence of carbon dioxide, respectively. This study demonstrates the controlling effects of both oxygen and carbon dioxide on TSST-1 production.

scholarly journals The Function of Haemoglobin in Relation to Filter Feeding in Leaf-Mining Chironomid Larvae

1951 ◽  
Vol 28 (1) ◽  
pp. 57-61
Author(s):  
BARBARA M. WALSHE
Keyword(s):  
Potassium Cyanide ◽  
The Other ◽  
Low Oxygen ◽  
Filter Feeding ◽  
Chironomid Larvae ◽  
Enzyme Systems ◽  
Leaf Mining ◽  
Cyanide Solutions ◽  
Blood Pigment ◽  
Oxygen Concentrations

1. The filter feeding of four species of leaf-mining chironomid larvae with and without functional haemoglobin was studied at different oxygen concentrations. 2. Two red species, Glyptotendipes pallens and Endochironomus dispar, showed at low oxygen concentrations a reduced amount of filter feeding after treatment with carbon monoxide (to render the haemoglobin functionless). The blood pigment is therefore of significance to these larvae in increasing the amount of feeding possible at low oxygen concentrations. 3. Two pale species, Endochironomus tendens and E. albipennis, however, despite their having little haemoglobin, were nevertheless capable of filter feeding in water poor in oxygen. 4. The capacity to live anaerobically was greatest in the red species. 5. In potassium cyanide solutions, on the other hand, the red Glyptotendipes pallens larvae were more rapidly affected than the pale Endochironomus tendens larvae. It is tentatively suggested, therefore, that the ability of the larvae poor in haemoglobin to filter feed at low oxygen concentrations may be due to their possession of respiratory enzyme systems, alternative to the cyanide-sensitive type, which are efficient at low oxygen pressures.

Effects of oxygen concentration on the metabolism of

1989 ◽  
Vol 1 (2) ◽  
pp. 99 ◽  
Author(s):  
NK Khurana ◽  
RG Wales
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Concentration ◽  
Glycogen Content ◽  
Carbon Dioxide Production ◽  
Morphological Development ◽  
Low Oxygen ◽  
Beneficial Effects ◽  
Low Oxygen Concentration ◽  
Oxygen Concentrations

The utilization of the acid-soluble glycogen pool in pulse-labelled embryos was significantly enhanced during 24- and 48-h chase culture under low oxygen concentrations of 5, 2.5 and 1%. The lower the oxygen tension the greater was the turnover in the pool. The morphological development of embryos was equally as good at very low oxygen concentrations as when embryos were cultured in 5-20% oxygen. Reduction in oxygen concentration enhanced the oxidative utilization of substrate, as measured by rate of carbon dioxide production. The present study could provide an explanation for the discrepancy in glycogen content between mouse blastocysts developing in utero and in vitro and for the reported beneficial effects of low oxygen concentration during development of embryos in culture.

scholarly journals Identification and Functional Analysis of ThADH1 and ThADH4 Genes Involved in Tolerance to Waterlogging Stress in Taxodium hybrid ‘Zhongshanshan 406’

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 225
Author(s):  
Lei Xuan ◽  
Jianfeng Hua ◽  
Fan Zhang ◽  
Zhiquan Wang ◽  
Xiaoxiao Pei ◽  
...  
Keyword(s):  
Ethanol Metabolism ◽  
Flooding Tolerance ◽  
Transcriptome Data ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Waterlogging Tolerance ◽  
Waterlogging Stress ◽  
Adh Genes ◽  
Oxygen Conditions ◽  
Stems And Leaves

The Taxodium hybrid ‘Zhongshanshan 406’ (T. hybrid ‘Zhongshanshan 406’) [Taxodium mucronatum Tenore × Taxodium distichum (L.). Rich] has an outstanding advantage in flooding tolerance and thus has been widely used in wetland afforestation in China. Alcohol dehydrogenase genes (ADHs) played key roles in ethanol metabolism to maintain energy supply for plants in low-oxygen conditions. Two ADH genes were isolated and characterized—ThADH1 and ThADH4 (GenBank ID: AWL83216 and AWL83217—basing on the transcriptome data of T. hybrid ‘Zhongshanshan 406’ grown under waterlogging stress. Then the functions of these two genes were investigated through transient expression and overexpression. The results showed that the ThADH1 and ThADH4 proteins both fall under ADH III subfamily. ThADH1 was localized in the cytoplasm and nucleus, whereas ThADH4 was only localized in the cytoplasm. The expression of the two genes was stimulated by waterlogging and the expression level in roots was significantly higher than those in stems and leaves. The respective overexpression of ThADH1 and ThADH4 in Populus caused the opposite phenotype, while waterlogging tolerance of the two transgenic Populus significantly improved. Collectively, these results indicated that genes ThADH1 and ThADH4 were involved in the tolerance and adaptation to anaerobic conditions in T. hybrid ‘Zhongshanshan 406’.

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