Gill Ventilation Volumes, Oxygen Consumption and Respiratory Rhythms in Carcinus Maenas (L.)

1964 ◽  
Vol 41 (2) ◽  
pp. 309-321
Author(s):  
K. D. ARUDPRAGASAM ◽  
E. NAYLOR

1. An apparatus is described for continuously measuring gill ventilation volumes in crabs. 2. Large Carcinus pump about 1 c.c./g./min. and consume oxygen at the rate of about 0.03 c.c./g./hr. whilst smaller specimens pump up to 1.5 c.c./g./min. and consume up to 0.1 c.c./g./hr. Freshly collected crabs show persistent tidal and 24 hr. rhythms of pumping activity and oxygen consumption. 3. In response to oxygen depletion Carcinus shows increased rates of gill ventilation and increased percentage utilization. Prolonged exposure to increased carbon dioxide results in a short-lived inhibition followed by over-compensation and then progressive inhibition of respiratory activity. 4. The results are discussed in relation to previous work on respiration in other decapod Crustacea.

1964 ◽  
Vol 41 (2) ◽  
pp. 299-307
Author(s):  
K. D. ARUDPRAGASAM ◽  
E. NAYLOR

1. A method is described for obtaining continuous records of the direction of flow of the respiratory current of Carcinus by recording changes of pressure in the gill chamber. 2. Frequent and rhythmic reversals of the normally forward-flowing respiratory current appear to irrigate the upper surfaces of the posterior gills and do not serve primarily to clean the gills. 3. The rate of reversal of this respiratory current increases spontaneously at times of high tide. It decreases under conditions of carbon-dioxide accumulation and increases under conditions of oxygen depletion in the absence of excess carbon dioxide. 4. The pattern of gill ventilation varies according to whether crabs are totally in water, partially buried in sand, or in very shallow water.


Author(s):  
Grażyna Mazurkiewicz-Boroń ◽  
Teresa Bednarz ◽  
Elżbieta Wilk-Woźniak

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.


1992 ◽  
Vol 70 (3) ◽  
pp. 408-411 ◽  
Author(s):  
Peter B. Frappell ◽  
Andrea Dotta ◽  
Jacopo P. Mortola

Aerobic metabolism (oxygen consumption, [Formula: see text], and carbon dioxide production, [Formula: see text]) has been measured in newborn rats at 2 days of age during normoxia, 30 min of hyperoxia (100% O2) and an additional 30 min of recovery in normoxia at ambient temperatures of 35 °C (thermoneutrality) or 30 °C. In normoxia, at 30 °C [Formula: see text] was higher than at 35 °C. With hyperoxia, [Formula: see text] increased in all cases, but more so at 30 °C (+20%) than at 35 °C (+9%). Upon return to normoxia, metabolism readily returned to the prehyperoxic value. The results support the concept that the normoxic metabolic rate of the newborn can be limited by the availability of oxygen. At temperatures below thermoneutrality the higher metabolic needs aggravate the limitation in oxygen availability, and the positive effects of hyperoxia on [Formula: see text] are therefore more apparent.Key words: neonatal respiration, oxygen consumption, thermoregulation.


1978 ◽  
Vol 86 (3) ◽  
pp. 1149-1151
Author(s):  
P. M. Gramenitskii ◽  
V. A. Galichii ◽  
N. V. Petrova ◽  
N. Yu. Leont'eva

1995 ◽  
Vol 41 (4-5) ◽  
pp. 372-377 ◽  
Author(s):  
João P. S. Cabral

Pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. The number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. The results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. Starvation also resulted in a decrease in the rate of oxygen consumption with acetate, glycerol, and succinate, but at different levels. Whereas the respiration of acetate and glycerol decreased concomitantly with culturability, the respiration of succinate decreased to levels similar to the concentration of intact cells, suggesting that all intact particles respired the succinate, but only the culturable cells respired the acetate and glycerol. The results suggest that measuring the activity of the electron-transport system can overestimate the viability of starved bacterial cells, and that complex metabolic activities such as the respiration of acetate and glycerol are probably better suited for the evaluation of this parameter.Key words: Pseudomonas syringae, starvation, culturability, viability, respiration.


PEDIATRICS ◽  
1964 ◽  
Vol 33 (1) ◽  
pp. 75-82
Author(s):  
Forrest H. Adams ◽  
Tetsuro Fujiwara ◽  
Robert Spears ◽  
Joan Hodgman

Thirty-four measurements of oxygen consumption, carbon dioxide production, respiratory quotient, and rectal temperature were made on 22 premature infants with ages ranging from 2½ hours to 18 days. The studies were conducted at 32-34°C utilizing an open circuit apparatus and a specially designed climatized chamber. Oxygen consumption and carbon dioxide production were lowest in the first 12 hours and increased thereafter. The rate of increase in O2 consumption was greater than that of CO2 production, with a consequent fall in respiratory quotient during the first 76 hours of life. A reverse relation of O2 consumption and CO2 production was found following the 4th day of life with a consequent rise in respiratory quotient. There was a close correlation between O2 consumption and rectal temperature regardless of age. A respiratory quotient below the value of 0.707 for fat metabolism was observed in 7 premature infants with ages ranging from 24 to 76 hours.


1958 ◽  
Vol 193 (3) ◽  
pp. 495-498 ◽  
Author(s):  
Ruth McClintock ◽  
Nathan Lifson

Measurements of oxygen consumption and carbon dioxide production were made by the Haldane open circuit method on hereditarily obese mice and littermate controls, and the energy expenditures were estimated. Studies were made on mice for short periods under ‘basal’ conditions, and for periods of approximately a day with the mice fasted and confined, fasted and relatively unconfined, and fed and unconfined. The total energy expenditures of fed and unconfined obese mice were found to be higher than those of nonobese littermate controls by virtue of a) increased ‘basal metabolism’, b) greater energy expenditure associated with feeding, and possibly c) larger energy output for activity despite reduced voluntary movement. The values obtained for total metabolism confirm those previously determined by an isotope method for measuring CO2 output.


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