Postfusion incompatibility in Physarum polycephalum: involvement of membranes

1985 ◽  
Vol 31 (9) ◽  
pp. 782-785 ◽  
Author(s):  
J. A. M. Schrauwen
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
Physarum Polycephalum ◽  
Membrane Composition ◽  
Lethal Reaction

Fusion of sensitive and killer plasmodia of Physarum polycephalum caused a change in membrane composition which did not occur after fusion of two sensitive plasmodia. This change, which was mainly the result of an increase in the synthesis of phosphatidylethanolamine, began 1.5 h after fusion. Heat production and oxygen consumption declined during the processes which underlie the lethal reaction which destroys the fused plasmodia of sensitive and killer strains.

scholarly journals No major thermogenic role for (Na+ + K+)-dependent adenosine triphosphatase apparent in hepatocytes from hyperthyroid rats

1982 ◽  
Vol 202 (3) ◽  
pp. 661-665 ◽  
Author(s):  
D G Clark ◽  
M Brinkman ◽  
O H Filsell ◽  
S J Lewis ◽  
M N Berry
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Atpase Activity ◽  
Heat Production ◽  
Adenosine Triphosphatase ◽  
Heat Output ◽  
Liver Parenchymal ◽  
Dependent Atpase ◽  
Parenchymal Cells ◽  
Isolated Liver

(Na+ + K+)-dependent ATPase activity, heat production and oxygen consumption were increased by 59%, 62% and 75% respectively in hepatocytes from tri-iodothyronine-treated rats. Ouabain at concentrations of 1 and 10 mM decreased oxygen uptake by 2-8% in hepatocytes from euthyroid rats and by 5-15% in hepatocytes from hyperthyroid animals. Heat output was decreased by 4-9% with the glycoside in isolated liver parenchymal cells from the control animals and by 11% in the cells from the tri-iodothyronine-treated animals. These results do not support the hypothesis that hepatic (Na+ + K+)-ATPase plays a major role in increased heat production in hepatocytes from hyperthyroid rats.

Metabolic Factors in the Development of Homeothermy in Dogs

1958 ◽  
Vol 194 (2) ◽  
pp. 293-296 ◽  
Author(s):  
Donald G. McIntyre ◽  
H. E. Ederstrom
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Rectal Temperature ◽  
Heat Production ◽  
Cold Exposure ◽  
Metabolic Factors ◽  
Air Temperatures ◽  
Heat Conservation

Dogs from 1 to 25 days of age were exposed to air temperatures of 5, 23 and 30°C and their oxygen consumption measured in a closed calorimeter. Animals 1–5 days old had a rise of 20–25% in metabolic rate, but rectal temperature fell, when they were exposed to 5 or 23°C. At 11–21 days of age dogs exposed to 5°C had a rise of about 75% in metabolic rate, but rectal temperature fell several degrees in 1 hour. In dogs 21–25 days of age metabolic rate increased about 75% at air temperatures of 5°C and rectal temperature fell only about 1°C. Under the same conditions a trained adult dog had a rise of 80% in metabolic rate, and no fall in rectal temperature. Since heat production in 2- to 3-week-old dogs was increased to about the same extent as in the adult on cold exposure, it was assumed that heat conservation lagged behind heat production in the development of homeothermy.

Effects of substrate and hypoxia on smooth muscle metabolism and contraction

1989 ◽  
Vol 256 (4) ◽  
pp. C719-C727 ◽  
Author(s):  
I. R. Wendt
Keyword(s):  
Smooth Muscle ◽  
Oxygen Consumption ◽  
Urinary Bladder ◽  
Heat Production ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Sufficient Energy ◽  
Rabbit Urinary Bladder

Suprabasal heat production, oxygen consumption, and lactate production were measured, together with force, in 30-s isometric contractions of longitudinal smooth muscle from rabbit urinary bladder at 27 degrees C. Either glucose or pyruvate was provided as exogenous substrate. Under aerobic conditions with glucose as substrate, force averaged 95 mN/mm2 and heat production 121 mJ/g. Oxygen consumption (0.18 mumol/g) could account for only two-thirds of the total energy expenditure represented as heat production. The remaining one-third was accounted for by aerobic lactate production (0.36 mumol/g). When pyruvate replaced glucose as substrate, both the force developed and the total heat liberated were unchanged. Oxygen consumption, however, increased by approximately 40% (to 0.25 mumol/g) and was able to fully account for the measured heat production. The frequency of spontaneous contractions under aerobic conditions was always reduced in the presence of pyruvate. Under anaerobic conditions force was essentially unaltered, and heat production was only slightly reduced (101 mJ/g) with glucose present. Lactate production increased threefold over that under aerobic conditions. With pyruvate as substrate both force and heat production declined markedly (to less than 5% of the aerobic values). The results indicate that under aerobic conditions and with glucose as substrate, smooth muscle of rabbit urinary bladder generates about one-third of its suprabasal energy requirements through glycolysis and that glycolysis can be further accelerated under anaerobic conditions to provide sufficient energy to sustain contraction. If pyruvate replaces glucose as substrate, the metabolism shifts to being virtually all oxidative, and contraction can no longer be sustained in the absence of oxygen.

Heat loss from feet of herring gulls at rest and during flight

1976 ◽  
Vol 230 (4) ◽  
pp. 920-924 ◽  
Author(s):  
RV Baudinette ◽  
JP Loveridge ◽  
KJ Wilson ◽  
CD Mills ◽  
K Schmidt-Nielsen
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Wind Tunnel ◽  
Heat Loss ◽  
Heat Production ◽  
Heat Dissipation ◽  
Larus Argentatus ◽  
Herring Gull ◽  
Herring Gulls

The role of the feet of herring gulls (Larus argentatus) in heat dissipation was estimated during rest and wind-tunnel flight. We determined the blood flow to the feet and the arteriovenous temperature difference and thus estimated heat loss from the feet. Determinations of oxygen consumption and respiratory water loss at rest gave a heat production of about 8 W; 37-56% of this heat was lost from the feet (air temp = 10-35 degrees C). During flight heat production was estimated to be about 57 W and heat loss from the feet was 46 W, about 80% of the heat production in flight. Thus the webbed feet are an important avenue of heat loss in the herring gull.

Postfusion incompatibility in Physarum polycephalum: changes in protein pattern of a heterokaryon

1985 ◽  
Vol 31 (9) ◽  
pp. 778-781 ◽  
Author(s):  
J. A. M. Schrauwen
Keyword(s):  
Protein Synthesis ◽  
Physarum Polycephalum ◽  
Protein Pattern ◽  
Two Dimensional ◽  
Polypeptide Patterns ◽  
Lethal Reaction ◽  
Different Strains

The polypeptide patterns of two different strains of Physarum polycephalum, sensitive and killer, showed only minor differences on two-dimensional electrophoretograms. After heterologous fusion of the sensitive and killer plasmodia, newly formed proteins could be demonstrated which were not detectable in homologous fused plasmodia. The lethal reaction did not occur until after the aforementioned protein synthesis.

A note on the effect of oxygen-compared with nitrogen-ventilated hay on energy retention of steers

1971 ◽  
Vol 13 (3) ◽  
pp. 557-560
Author(s):  
K. H. Menke ◽  
W. Schneider
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Heat Production ◽  
Energy Retention ◽  
Effect Of Oxygen

SUMMARYVentilation of hay with oxygen increased oxygen consumption (P< 0·001) and carbon dioxide formation (P<0·01) of two steers, when compared with nitrogen-ventilated hay. Heat production was about 5% higher in the oxygen-hay period than in the nitrogen-hay period (P< 0·001). No difference in digestibility of nutrients was observed between these treatments.

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