Temperature acclimation influences temperature-related behaviour as well as oxygen-transport physiology and biochemistry in the water flea Daphnia magna

2003 ◽  
Vol 81 (2) ◽  
pp. 237-249 ◽  
Author(s):  
Tobias Lamkemeyer ◽  
Bettina Zeis ◽  
Rüdiger J Paul
Keyword(s):  
Oxygen Consumption ◽  
Daphnia Magna ◽  
Oxygen Concentration ◽  
Oxygen Transport ◽  
Oxygen Affinity ◽  
Low Oxygen ◽  
High Concentration ◽  
Water Flea ◽  
Two Dimensional Gel Electrophoresis ◽  
Physiology And Biochemistry

To evaluate the role of temperature in oxygen transport in the water flea Daphnia magna, temperature-related behaviour as well as oxygen-transport physiology and biochemistry were investigated in animals long-term acclimated to moderate temperatures: 10, 20, or 30°C (normoxia) or 20°C (hypoxia). Study of the behaviour of animal groups within a normoxic thermal gradient showed their preferred temperatures and distribution patterns to be connected with acclimation conditions; for example, cold-acclimated individuals, with their relatively high metabolic rates and low oxygen-transport capacities, crowded at low temperatures where the oxygen concentration was high. One key to explaining these data is to assume a strategy of avoiding oxygen shortage. Both temperature and hypoxia acclimation also modified oxygen-transport variables such as oxygen consumption, ventilation and circulation rates, or the concentration and oxygen affinity of haemoglobin. Characteristic features of cold-acclimated D. magna were relatively high oxygen-consumption and heart rates and a low concentration and oxygen affinity of haemoglobin. Hypoxia-acclimated D. magna showed relatively low convective rates (frequency of thoracic-limb movements, heart rate) but a high concentration and oxygen affinity of haemoglobin. Additional experiments showed that independently of each other, temperature and ambient oxygen concentration modify haemoglobin quantity and quality, the former possibly acting via a temperature-induced hypoxia. The varying oxygen affinity is probably due to alterations of haemoglobin subunit composition, with the particular participation of subunits A, E, and G as revealed by two-dimensional gel electrophoresis.

scholarly journals Zooplankton fluctuations in Jurumirim Reservoir (São Paulo, Brazil): a three-year study

2009 ◽  
Vol 69 (1) ◽  
pp. 1-18 ◽  
Author(s):  
LP. Sartori ◽  
MG. Nogueira ◽  
R. Henry ◽  
EM. Moretto
Keyword(s):  
Water Column ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Sao Paulo ◽  
Seasonal Effect ◽  
São Paulo ◽  
Low Oxygen ◽  
High Concentration ◽  
Heterogeneous Distribution ◽  
Low Oxygen Concentration

During three consecutive years, monthly samples of zooplankton were taken in the lacustrine (dam) zone of Jurumirim (São Paulo, Brazil). The seasonal effect on basic limnological features (thermal regime, oxygen distribution, phytoplankton biomass, etc.) was also examined. The influence of the seasonality on the fluctuation of the zooplankton composition and abundance was not clearly detected (low degree of recurrent patterns). Rotifers (32 taxa) were the most abundant organisms during almost the entire study period with some seasonal alternations in the maximum abundance peaks of the main taxa (Conochilus unicornis, Keratella americana, K. cochlearis and Hexarthra spp.), except for Polyarthra (mainly P. vulgaris). Only occasionally copepods were numerically dominant. Higher copepod abundance was positively associated to periods of increase in the water retention time. Among the Copepoda (10 taxa) the calanoids (mainly Notodiaptomus iheringi) were more abundant, especially in warmer periods. Conversely, cyclopoids had higher abundance in autumn and winter. The species Thermocyclops minutus and T. decipiens co-occurred, but the first attained higher abundance. Some evidence of co-existence strategies between both species are considered. Cladocera (17 taxa) was never numerically dominant and the main taxa (Bosmina spp., Ceriodaphnia spp. and Diaphanosoma spp.) occurred almost the whole study period and did not present a seasonal pattern of fluctuation. Diaphanosoma (mainly D. birgei) attained the highest abundance among cladocerans. Most organisms were always found at the surface, but they also occupy the whole water column, even in periods of stratified conditions and low oxygen concentration in the bottom layers. Among the main zooplanktonic taxa, only Hexarthra avoids deep layers. An exceptionally high concentration of Copepoda nauplii on the surface was influenced by low transparency, high concentration of phytoplankton at this layer and low oxygen concentration at the bottom. In periods of higher retention timevariability there was a more heterogeneous distribution of the zooplankton in the water column. The increase in the retention time seems also to favor the copepod development. Finally, some inter-decade changes are considered on the basis of zooplankton assemblage structure observations.

Circulatory oxygen transport in the water flea Daphnia magna

2002 ◽  
Vol 172 (4) ◽  
pp. 275-285 ◽  
Author(s):  
Bäumer C. ◽  
Pirow R. ◽  
Paul R.
Keyword(s):  
Daphnia Magna ◽  
Oxygen Transport ◽  
Water Flea

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.

Blood oxygen transport and organ weights of two shrew species (S. etruscus and C. russula)

1979 ◽  
Vol 236 (3) ◽  
pp. R221-R224 ◽  
Author(s):  
H. Bartels ◽  
R. Bartels ◽  
R. Baumann ◽  
R. Fons ◽  
K. D. Jurgens ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Oxygen Transport ◽  
Blood Cells ◽  
Saturation Pressure ◽  
Oxygen Affinity ◽  
Hemoglobin Concentration ◽  
Mean Corpuscular Hemoglobin ◽  
Blood Oxygen ◽  
Low Oxygen ◽  
Organ Weights

Blood parameters concerning oxygen transport and relative organ weights of 11 Suncus etruscus and 13 Crocidura russula under light halothane anesthesia were investigated. Mean body weight of S. etruscus was 2.5 g and for C. russula was 9 g, hemoglobin concentration was 17.4 and 15.6 g/100 ml blood, hematocrit was 50 and 44%, red blood cells were 18 and 11 X 10(6)/microliter, respectively. Mean corpuscular volume was calculated to be 26 and 41 micron3, mean diameter 5.5 and 7 micron, and mean thickness 1.2 and 1.1 micron, respectively. Mean corpuscular hemoglobin concentration was in the normal range of mammalian red blood cells. A blood oxygen half-saturation pressure of 35 and 34 Torr at pH 7.4, 37 degrees C and a Bohr factor deltalog P50/deltapH of -0.61 and -0.66 was measured. Experiments with stripped hemoglobin showed that 2,3-diphosphoglycerate is the main oxygen affinity reducing allosteric factor. Relative weights of heart, kidney, and liver are remarkably high in S. etruscus. The maximal oxygen transport of 400 ml . kg-1 . min-1 of S. etruscus is feasible by an enormous heart rate, a large relative stroke volume, a high hemoglobin concentration combined with a low oxygen affinity, and a large Bohr effect.

scholarly journals Anaesthesia-Specifi c Oxygen Transport Assessment in Robot-Assisted Pelvic Surgery: a Clinical Trial

2021 ◽  
Vol 11 (4) ◽  
pp. 307-315
Author(s):  
I. I. Lutfarakhmanov ◽  
S. T. Lazarev ◽  
N. A. Zdorik ◽  
A. D. Lifanova ◽  
A. A. Grazhdankin ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Adverse Events ◽  
Oxygen Transport ◽  
Oxygen Delivery ◽  
Functional Class ◽  
Adverse Outcomes ◽  
Pelvic Surgery ◽  
Low Oxygen ◽  
Robot Assisted ◽  
Trendelenburg Position

Background. Robot-assisted pelvic surgery rapidly becomes a choice in surgeries for gynaecological oncology and urology. These interventions require special settings (pneumoperitonaeum and Trendelenburg position), which inevitably and systemically impact oxygen transport. Low oxygen delivery during surgery associates with manifold adverse outcomes. A single universal oxygen delivery threshold is impractical, as oxygen consumption must be taken into account. This study examines the effects of pneumoperitonaeum and Trendelenburg position on oxygen transport in patients of ASA functional class I–III (as per American Society of Anaesthesiologists).Materials and methods. Delivery, consumption, oxygen extraction, perioperative adverse events and type of general anaesthesia were prospectively studied in 126 adult patients.Results and discussion. Mean oxygen consumption was 242 mL/min/m2 , mean oxygen delivery — 612 mL/min/m2 . Oxygen delivery was below median 529 mL/min/m2 in 54 (43  %) patients. Perioperative adverse events developed in 36 (29 %) patients. A strong correlation (r > 0.500; p<0.001) between oxygen delivery and consumption was observed in 54 patients. Blood lactate level of 2.7 mmol/L at surgery end was indicative of inadequate oxygen delivery.Conclusion. No relationship was revealed between oxygen delivery and adverse perioperative events, and neither — between oxygen delivery and consumption relative to a particular anaesthetic.

Characterisation of production of organic rich topsoil from sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 195-201 ◽  
Author(s):  
P. Andreasen ◽  
P. B. Mortensen ◽  
A. Stubsgaard ◽  
B. Langdahl
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Mineral Soil ◽  
Climatic Conditions ◽  
Growth Media ◽  
Soil Mixture ◽  
Water Suspension ◽  
Aerobic Process ◽  
Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

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