Respiration in the African Lungfish Protopterus Aethiopicus

1968 ◽  
Vol 49 (2) ◽  
pp. 437-452 ◽  
Author(s):  
CLAUDE LENFANT ◽  
KJELL JOHANSEN
Keyword(s):  
Gas Exchange ◽  
Haemoglobin Concentration ◽  
Temperature Shift ◽  
Mean Value ◽  
Gas Analysis ◽  
Air Exposure ◽  
Air Breathing ◽  
African Lungfish ◽  
High Degree ◽  
Protopterus Aethiopicus

1. Respiratory properties of blood and pattern of aerial and aquatic breathing and gas exchange have been studied in the African lungfish, Protopterus aethiopicus. 2. The mean value for haematocrit was 25%. Haemoglobin concentration was 6.2 g% and O2 capacity 6.8 vol. %. 3. The affinity of haemoglobin for O2 was high. P50 was 10 mm. Hg at PCOCO2, 6 mm. Hg and 25 °C. The Bohr effect was smaller than for the Australian lungfish, Neoceratodus, but exceeded that for the South American lungfish, Lepidosiren. The O2 affinity showed a larger temperature shift in Protopterus than Neoceratodus. 4. The CO2 combining power and the over-all buffering capacity of the blood exceeded values for the other lungfishes. 5. Both aerial and aquatic breathing showed a labile frequency. Air exposure elicited a marked increase in the rate of air breathing. 6. When resting in aerated water, air breathing accounted for about 90% of the O2 absorption. Aquatic gas exchange with gills and skin was 2.5 times more effective than pulmonary gas exchange in removing CO2. The low gas-exchange ratio for the lung diminished further in the interval between breaths. 7. Protopterus showed respiratory independence and a maintained O2 uptake until the ambient O2 and CO2 tensions were 85 and 35 mm. Hg respectively. A further reduction in O2 tension caused an abrupt fall in the oxygen uptake. 8. Gas analysis of blood samples drawn from unanaesthetized, free-swimming fishes attested to the important role of the lung in gas exchange and the high degree of functional separation in the circulation of oxygenated and deoxygenated blood.

Respiration in the African Lungfish Protopterus Aethiopicus

1968 ◽  
Vol 49 (2) ◽  
pp. 453-468
Author(s):  
KJELL JOHANSEN ◽  
CLAUDE LENFANT
Keyword(s):  
Regional Blood Flow ◽  
Air Exposure ◽  
Lung Inflation ◽  
Air Breathing ◽  
Pulmonary Flow ◽  
Hypoxic Water ◽  
African Lungfish ◽  
Systemic Arteries ◽  
Arterial Po2 ◽  
Protopterus Aethiopicus

1. Factors controlling aerial and aquatic breathing have been studied in the intact, free-swimming African lungfish, Protopterus aethiopicus. Frequencies of aerial and branchial breathing were correlated with gas tensions in the lung and in blood from pulmonary and systemic arteries and veins. 2. Studies were made, on fish resting in aerated water, during exposure to air and during hypoxic and hypercarbic conditions in the environment. 3. Both branchial and pulmonary breathing were irregular during rest in aerated water. The rate of branchial breathing normally exceeded that of air breathing. An increased rate and vigour of branchial breathing commonly preceded an air breath. There was no indication that a new air breath was related to the values of arterial Po2 and pH. 4. Air exposure elicited a marked and immediate increase in the rate of air breathing. Hypoxic water never evoked any compensatory breathing responses while breathing from a hypoxic gas mixture quickly increased the rate of air breathing. Bubbling 5% CO2 in air into the aquarium caused a reduction in branchial breathing while the rate of air breathing increased. 5. Nicotine injected intravenously or in the water close to the gills elicited an increase in both aerial and branchial breathing. 6. Respiratory and circulatory events were correlated during undisturbed breathing and during artificial lung inflation. Increased cardiac output and a shift in regional blood flow to a higher pulmonary flow occurred with air breaths.

Oxygen uptake in air and water in the air-breathing reedfish Calamoichthys calabaricus: role of skin, gills and lungs

1982 ◽  
Vol 97 (1) ◽  
pp. 179-186
Author(s):  
R. Sacca ◽  
W. Burggren
Keyword(s):  
Gas Exchange ◽  
Oxygen Uptake ◽  
Natural Environment ◽  
Average Duration ◽  
O2 Uptake ◽  
Total Oxygen ◽  
Air Exposure ◽  
Air Breathing

The reedfish Calamoichthys calabaricus (Smith) is amphibious, making voluntary excursions on to land (in a simulated natural environment) an average of 6 +/− 4 times/day for an average duration of 2.3 +/− 1.3 min. Oxygen uptake is achieved by the gills, skin and large, paired lungs. In water at 27 degrees C, total oxygen uptake is 0.088 ml O2/g.h. The lungs account for 40%, the gills 28%, and the skin 32% of total VO2. Total oxygen uptake during 2 h of air exposure increases from 0.117 ml O2/g.h to 0.286 ml O2/g.h, due largely to an enhanced lung VO2 and a small increase in skin VO2. Calamoichthys is both capable of aerial gas exchange and adapted to maintain O2 uptake during brief terrestrial excursions.

Aerial CO2 Excretion in the Obligate Air Breathing Fish Trichogaster Trichopterus: A Role for Carbonic Anhydrase

1979 ◽  
Vol 82 (1) ◽  
pp. 215-225
Author(s):  
WARREN BURGGREN ◽  
STEVE HASWELL
Keyword(s):  
Gas Exchange ◽  
Carbonic Anhydrase ◽  
Potent Inhibitor ◽  
Total Oxygen ◽  
Air Exposure ◽  
Vitro Assay ◽  
Air Breathing ◽  
Highly Effective ◽  
Co2 Excretion

Total oxygen uptake and carbon dioxide excretion and their partitioning between gills and aerial exchange organs have been measured in an obligate air breathing fish, the blue gourami (Trichogaster trichopterus). Measurements were made during normal bimodal breathing and in air-exposed fish. MO2 increased during air exposure, but the aerial exchange organs or ‘labyrinth’ of Trichogaster could assume a highly effective CO2 excretion in the absence of branchial gas exchange. Hence, aerial MCO2 was greatly increased during air exposure, and the labyrinth gas exchange ratio increased to 0.8 from the value of 0.1 evident during bimodal gas exchange. The large aerial CO2 excretion in Trichogaster, unobtainable in many air breathing fish, was unaffected by the injection of carbonic anhydrase, but was seriously disrupted in the presence of this enzyme's potent inhibitor, acetazolamide. In vitro assay for carbonic anhydrase demonstrated the labyrinth epithelium of the gourami to be rich in this enzyme. It is concluded that highly effective CO2 excretion from the labyrinth organs during air exposure in Trichogaster results from dehydration of plasma bicarbonate to molecular CO2 at the catalysed rate; carbonic anhydrase for this purpose being present in the labyrinth epithelium. The distribution of carbonic anyhdrase in the tissues of other air breathing fishes is determined, and its implications to aerial CO2 excretion discussed.

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

scholarly journals Bark Characteristics of Scots Pine Logs

2020 ◽  
Vol 3 (1) ◽  
pp. 66
Author(s):  
Ferréol Berendt ◽  
Erik Pegel ◽  
Lubomir Blasko ◽  
Tobias Cremer
Keyword(s):  
Scots Pine ◽  
Tree Species ◽  
Waste Product ◽  
Mean Value ◽  
Bark Thickness ◽  
Water Displacement ◽  
Federal States ◽  
Bark Damage ◽  
Great Relevance ◽  
High Degree

The wood of Scots pine (Pinus sylvestris L.) shows good properties as building and construction timber but also as furniture or pulp and paper, and thus, is one of the most commercially important European tree species. Scots pine are mostly harvested and processed with a high degree of mechanization. In Northeast Germany (federal states of Brandenburg and Berlin), 36% of harvested Scots pine have a diameter at breast height (DBH) between 7 and 19.9 cm. As a typical industrial wood assortment, a large proportion of the resulting small-sized logs are used in the wood industry to produce boards. Although bark is considered a by-product or waste product of the industry, no actual study has quantified the bark thickness, bark volume, bark mass and bark damage of such Scots pine logs. Therefore, the bark characteristics from 50 logs from 10 different piles were analyzed. Bark volume was quantified using the water displacement method, bark mass by weighing, bark thickness with a precision caliper and bark damage by tape measurements. The diameters of the analyzed 150 log discs were normally distributed and the mean value was 12.9 cm. The results showed average bark damages from 12.0%, which were mostly caused during the felling and processing of logs with the harvester. No significant correlation was found between double bark thickness (mean: 3.0 mm) and the diameter; whereas fresh bark volume (mean: 5.6%) and dry bark mass (mean: 3.3%) were significantly affected by the diameter. As shown for spruce by other authors, bark characteristics may change over time and therefore, should be measured regularly. Moreover, it was shown that bark parameters are site dependent. Thus, quantifying bark characteristics for economically important tree species at both the local and national scale is of great relevance. More detailed analyzes are described by Berendt et al. (2021) [1].

Effect of short-term exposure to high ambient temperatures on gas exchange and heat production in boars of different breeds

1998 ◽  
Vol 66 (2) ◽  
pp. 431-440 ◽  
Author(s):  
A.-H. Tauson ◽  
A. Chwalibog ◽  
J. Ludvigsen ◽  
K. Jakobsen ◽  
G. Thorbek
Keyword(s):  
Heat Stress ◽  
Gas Exchange ◽  
Heat Production ◽  
Live Weight ◽  
Mean Value ◽  
Short Term ◽  
Ambient Temperatures ◽  
Cooling Period ◽  
Basal Period ◽  
Short Term Exposure

AbstractThe effects of short-term exposure to high ambient temperatures on gas exchange, heat production (HE), respiration rate (RR) and rectal temperature were evaluated individually with boars of approximately 100 kg live weight. The boars were of different breeds with four of Yorkshire (YS), eight of Danish Landrace (DL), out of which three were found stress susceptible by the halothane test (DLH+), eight of Duroc (DR) and eight of Hampshire (HS) breeds. After 1 h rest in the respiration chamber at 17·0°C the gas exchange measurements started with al-h basal period at 17 °C, followed by 2h of heating during which temperature increased to 35·0 °C (period I) and then further to 39·7X1 (period II). Then cooling of the chamber started, and after 1 h (period III) temperature had decreased to 21·8°C, and after the 2nd h of cooling (period IV) temperature was 18·2 °C. The gas exchange was measured for each hour from 09.00 h (basal period) until 14.00 h (period IV). RR was recorded every 15 min. Rectal temperatures were measured when the animals were removed from the chamber. The gas exchange and HE increased slowly during period I but rapidly in period II, followed by decreasing values in the cooling periods. HS and DLH+ had considerably higher gas exchange and HE than other breeds in these two periods and the values remained high during period III. In period IV all breeds had gas exchange rates and HE below those of the basal period. RR increased slightly in period I and then a sharp increase followed during period II. Maximum RR was recorded in period III with an average of 183 breaths per min for all breeds. RR increased earlier and more steeply in HS and reached the highest mean value of 236 breaths per min. Four HS boars salivated heavily during heat stress and rectal temperatures of these animals were 39·7 °C when removed from the chamber compared with close to 39·0 °C for all other breeds. It was concluded that there were considerable breed differences in response to heat stress and that DLH+ and HS were more severely stressed than boars ofYS, DL and DR.

Vasculature of the Gas-Exchange Organs in Air-Breathing Brachyurans

1990 ◽  
Vol 63 (1) ◽  
pp. 117-139 ◽  
Author(s):  
Peter Greenaway ◽  
Caroline Farrelly
Keyword(s):  
Gas Exchange ◽  
Air Breathing

scholarly journals Examination of Haematotoxicity of Fixed-Dose Highly Active Antiretroviral Drug in Albino Wistar Rats

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Thomas Nubila ◽  
Ernest O. Ukaejiofo ◽  
Nkoyo I. Nubila ◽  
Godfrey I. Okorie
Keyword(s):  
Highly Active Antiretroviral Therapy ◽  
Wistar Rats ◽  
Venous Blood ◽  
Haemoglobin Concentration ◽  
Test Group ◽  
Mean Value ◽  
Fixed Dose ◽  
Control Group ◽  
Highly Active ◽  
Significant Difference

Highly active antiretroviral therapy (HAART) is considered toxic and has other life-threatening side effects. Our aim was to evaluate the haematotoxic effects of lamivudine, zidovudine, and nevirapine fixed-dose combinations in Albino Wistar rats. Fifty (50) three (3) months old male Albino Wistar rats weighing between 200 and 250 g were randomly assigned to five (5) groups (A, B, C, D, and E). Group A served as control. Two (2 mLs) of venous blood was aseptically collected on Days 5, 10, 15, 20, and 25 of treatment. Red blood cell (RBC) mean value recorded statistically significant increase () in groups B and C when compared with the control group on Day 5. However, there was a statistically significant decrease () in RBC, haemoglobin concentration (Hb), packed cell volume (PCV), and some red cell indices on Day 10. In addition there was no statistically significant difference () in all the parameters evaluated when the test group was compared with the control on Day 25. Furthermore, there was a time-related statistically significant increase () in the two major blood cells—RBC and platelet counts. From the result of this present study, it can be concluded that HAART when administered in fixed-dose combinations have no subacute haematotoxic effects.

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