scholarly journals A Study of the Oxygen Consumption of Five Species of Leech

1956 ◽  
Vol 33 (3) ◽  
pp. 615-626
Author(s):  
K. H. MANN
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Body Surface ◽  
The Body ◽  
The Other ◽  
High Rate ◽  
Eutrophic Lakes ◽  
Stagnant Water ◽  
Low Concentrations

1. The oxygen consumption of five species of leech has been investigated and considered in relation to their ecology. 2. Glossiphonia complanata and Erpobdella octoculata which are most common in, but not confined to, hard and soft water streams respectively, have their oxygen consumption dependent on the concentration of dissolved oxygen, at least in spring and summer. Their oxygen uptake is not affected by acclimatization overnight to a low level of oxygen, but the uptake of Glossiphonia at the higher oxygen concentrations is depressed in winter. 3. Erpobdella testacea has an oxygen consumption which is independent of the oxygen concentration between 6.0 and 3.0 ml./l., provided that the leeches have been acclimatized overnight to the oxygen concentration at which their uptake is measured. Ventilation of the body surface by dorso-ventral undulations appears to be an important factor in the maintenance of a high rate of oxygen uptake at low concentrations. This species is found in reed swamps. 4. Helobdella stagnalis, which is most abundant in stagnant eutrophic lakes, maintains a level of oxygen consumption which is independent of the oxygen concentration between 2.0 and 4.0 ml./l., even without previous acclimatization. 5. Piscicola geometra, which is virtually absent from stagnant water, has a higher rate of oxygen uptake than any of the other species under conditions of air-saturation, and its rate is strictly dependent on the concentration of oxygen in the water.

Transepithelial movement of calcium in crustaceans

1993 ◽  
Vol 184 (1) ◽  
pp. 1-16 ◽  
Author(s):  
D. S. Neufeld ◽  
J. N. Cameron
Keyword(s):  
Active Transport ◽  
Calcium Concentration ◽  
Cellular Mechanism ◽  
The Body ◽  
High Rate ◽  
Calcium Flux ◽  
Moult Cycle ◽  
Electrochemical Gradient ◽  
Low Concentration ◽  
Low Concentrations

The regulation of calcium in most crustaceans is especially challenging owing to the highly mineralized cuticle that must be recalcified after each moult, a process that often occurs in environments with low concentrations of calcium. The gill and carapace epithelia separate the major calcium-containing compartments of the body and therefore see large changes in the rate of calcium flux through the moult cycle. Large changes in the ultrastructure of these cells do not, however, correlate well with the periods of calcium movement and probably reflect other physiological events. Despite the challenges to regulating calcium levels at various acclimation salinities and moult stages, the calcium concentration in the blood is maintained relatively constant. There is a rapid increase to a high rate of calcium flux across both the gill and carapace epithelium shortly after the moult; on an area-specific basis these fluxes are among the highest reported for calcium-transporting epithelia. When in water with a very low concentration of calcium, the electrochemical gradient for calcium is directed outwards and net influx must occur by active transport. Evidence suggests that changes in the electrochemical gradient, permeability and active transport are all important in the ability of crustaceans to take up calcium from water with a low concentration of this ion. Although an enzyme transporter is presumably involved in the active transport of calcium across epithelia, very little is known about the cellular mechanism of the transepithelial movement of calcium in crustaceans.

Tick Defense Strategies in Bison: The Role of Grooming and Hair Coat

Behaviour ◽  
1998 ◽  
Vol 135 (6) ◽  
pp. 693-718 ◽  
Author(s):  
Michael Mooring ◽  
William Samuel
Keyword(s):  
Body Surface ◽  
Cervus Elaphus ◽  
Attachment Site ◽  
The Body ◽  
Bison Bison ◽  
High Rate ◽  
Larval Feeding ◽  
Physical Barrier ◽  
Hair Coat ◽  
Winter Tick

AbstractGrooming behaviour, and its effectiveness in controlling infestation by the winter tick (Dermacentor albipictus), was studied for plains bison (Bison bison bison) in Elk Island National Park, Alberta, Canada from October 1995 through June 1996. Bison had few ticks (mean, 133 ticks per animal; 0.009 ticks per cm2), particularly in comparison with smaller sympatric cervids (moose, Alees alees; elk, Cervus elaphus; and white-tailed deer, Odocoileus virginianus), suggesting that tick defense in bison is highly effective. Bison performed grooming or grooming-like behaviours (oral grooming, scratching, rubbing, and wallowing) at a high rate during October, when winter tick larvae were blood feeding, but groomed very little from November to April, when nymphal and adult ticks predominated. Grooming in October probably removed many larval ticks while they were still unattached and traversing the body surface in search of an attachment site. Because bison groomed at the highest rate during the larval feeding period, when they were subjected to the lowest intensity of tick stimulation, grooming in bison appears to be centrally programmed rather than stimulus driven. This might be the only time ticks are vulnerable to grooming activity because bison have an extremely thick hair coat (a morphological adaptation to extreme cold), which probably serves as a physical barrier to infestation by ticks. The tightly packed mat of primary hairs at the skin surface (the highest density of primary hairs among bovids) likely forced larval ticks to traverse much of the body surface on top of the hair coat, making them vulnerable to being removed through licking and other grooming activity. Little grooming throughout late autumn and winter (November-March) corresponded to the period of coldest temperatures and snow on the ground, and was probably due to the bison's 'thermal inertia' strategy of energy conservation in which physical activity is minimized during the times of greatest cold stress, when forage is least available and of poorest quality. Newly born bison calves, 2 months old or younger, delivered 15-20 times more oral grooming per hour and 6 times more episodes per bout than did adult cows. This result is in accordance with the prediction of the body size principle of the programmed grooming hypothesis, which maintains that smaller animals should groom more frequently in order to maintain fewer ticks. Programmed grooming, which removes most larval ticks before they can attach, and the physical barrier of the dense hair coat, are proposed as the major reasons that bison host few D. albipictus.

The relationship between cirral activity and oxygen uptake in Balanus balanoides

1965 ◽  
Vol 45 (2) ◽  
pp. 387-403 ◽  
Author(s):  
R. C. Newell ◽  
H. R. Northcroft
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Mantle Cavity ◽  
The Body ◽  
Effect Of Temperature ◽  
Zero Rate ◽  
Rate Of Oxygen Consumption ◽  
The Relationship ◽  
Balanus Balanoides

The rate of cirral beat of Balanus balanoides is related to the logarithm of the body weight as an exponential function. In any one animal, there is little effect of temperature on cirral activity between 7·5° and 10° C. Between 10° and 20° C, however, there is a rapid increase in cirral beat with temperature followed by a fall at temperatures above 20° C.Balanus balanoides exhibits a fast, medium and zero rate of oxygen consumption. These rates of oxygen consumption correspond with (a) normal cirral beating, (b) ‘testing’ activity with no cirral movement, and (c) with the closure of the mantle cavity. Both of the possible levels of oxygen uptake are related to the logarithm of the body weight in a logarithmic fashion over the temperature range 7·5°–22·5° C. Temperature affects the two rates of oxygen consumption differently. In the slower rate (rate B) there is an increase in the rate of oxygen consumption between 7·5° and 14° C but there is no significant increase in the rate of oxygen consumption between 14° and 22·5 C°.

scholarly journals A redescription of deep-channel ghost knifefish, Sternarchogiton preto (Gymnotiformes: Apteronotidae), with assignment to a new genus

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Maxwell J. Bernt ◽  
Aaron H. Fronk ◽  
Kory M. Evans ◽  
James S. Albert
Keyword(s):  
Sexual Dimorphism ◽  
Body Surface ◽  
Type Species ◽  
New Genus ◽  
Phylogenetic Analyses ◽  
The Body ◽  
The Other ◽  
Valid Species ◽  
Deep Channel ◽  
Secondary Sexual Dimorphism

ABSTRACT From a study of morphological and molecular datasets we determine that a species originally described as Sternarchogiton preto does not form a monophyletic group with the other valid species of Sternarchogiton including the type species, S. nattereri. Previously-published phylogenetic analyses indicate that this species is sister to a diverse clade comprised of six described apteronotid genera. We therefore place it into a new genus diagnosed by the presence of three cranial fontanels, first and second infraorbital bones independent (not fused), the absence of an ascending process on the endopterygoid, and dark brown to black pigments over the body surface and fins membranes. We additionally provide a redescription of this enigmatic species with an emphasis on its osteology, and provide the first documentation of secondary sexual dimorphism in this species.

The Relative Losses of Sodium in the Urine and Across the Body surface in the Amphipod, Gammarus Duebeni

1965 ◽  
Vol 42 (1) ◽  
pp. 59-69
Author(s):  
A. P. M. LOCKWOOD
Keyword(s):  
Body Surface ◽  
Sea Water ◽  
Average Rate ◽  
The Body ◽  
High Rate ◽  
Water Turnover ◽  
Urine Production ◽  
Sodium Loss ◽  
And Diffusion ◽  
Total Sodium

1. The relative contributions of urine production and diffusion across the body surface to the loss of sodium from the body of the amphipod Gammarus duebeni have been investigated. 2. When the urine is isotonic to the blood some 80% of the total sodium loss is via the urine. 3. As the gradient between blood and medium is increased in dilute media production of urine hypotonic to the blood counteracts the tendency for sodium loss to increase. 4. In consequence, the average rate of sodium uptake at the body surface by animals acclimatized to 2% sea water needs to be only about twice that of animals acclimatized to 50% sea water. 5. It is suggested that the conservation of ions within the body by the production of hypotonic urine is likely to be found to be a common feature of the smaller brackish water crustacea, especially those with a high rate of water turnover.

Evolution of the Chondrophora: Evidence from Behavioural Studies on Velella

1971 ◽  
Vol 28 (10) ◽  
pp. 1595-1602 ◽  
Author(s):  
W. Gordon Fields ◽  
G. O. Mackie
Keyword(s):  
Body Surface ◽  
The Body ◽  
The Other ◽  
Large Individual

The chondrophore Velella shows concert behaviour closely resembling and presumably homologous to that described for Porpita, Pelagohydra, and for the sessile tubularian hydroids Tubularia and Corymorpha. The movements consist of orally directed tentacular flexions, accompanied by retraction of the blastostyles, along with muscular contractions in the mantle and in the crest surmounting the sail. Concerts may consist of single contractions or sequences of contractions, the latter sometimes summing to produce a sustained declination of the tentacles or contraction in the other parts. Concerts are repeated periodically at intervals of between 1 and 3 min.Electrical potentials (concert pulses) are recorded from all parts of the body surface at each concert contraction. The potentials are through-conducted at 30–35 cm/sec in parts of the aboral surface. Feeding changes the concert pattern, introducing a type of event called a feeding pulse. Peristalsis in the proboscis, as in Tubularia, is exhibited without electrical concomitants.The observations support the view of Velella as a large individual hydroid in no way comparable to a siphonophore. It is regarded as a floating tubularian hydranth with inverted stem. Velella and Porpita (family Velellidae) are assigned to the superfamily Tubularoidea. The freshwater hydra shows a type of behaviour resembling modified tubularian concerts, and its possible affinity with the tubularoid group is discussed.

Whole body and splanchnic oxygen consumption and blood flow after oral ingestion of fructose or glucose

1993 ◽  
Vol 264 (4) ◽  
pp. E504-E513 ◽  
Author(s):  
T. Brundin ◽  
J. Wahren
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
The Body ◽  
Splanchnic Blood Flow ◽  
Whole Body ◽  
Co2 Production ◽  
Arterial Blood ◽  
Splanchnic Oxygen

The contribution of the splanchnic tissues to the initial 2-h rise in whole body energy expenditure after ingestion of glucose or fructose was examined in healthy subjects. Indirect calorimetry and catheter techniques were employed to determine pulmonary gas exchange, cardiac output, splanchnic blood flow, splanchnic oxygen uptake, and blood temperatures before and for 2 h after ingestion of 75 g of either fructose or glucose in water solution or of water only. Fructose ingestion was found to increase total oxygen uptake by an average of 9.5% above basal levels; the corresponding increase for glucose was 8.8% and for water only 2.5%. The respiratory exchange ratio increased from 0.84 in the basal state to 0.97 at 45 min after fructose ingestion and rose gradually after glucose to 0.86 after 120 min. The average 2-h thermic effect, expressed as percent of ingested energy, was 5.0% for fructose and 3.7% for glucose (not significant). Splanchnic oxygen consumption did not increase measurably after ingestion of either fructose or glucose. The arterial concentration of lactate rose, arterial pH fell, and PCO2 remained essentially unchanged after fructose ingestion. Glucose, but not fructose, elicited increases in cardiac output (28%) and splanchnic blood flow (56%). Fructose, but not glucose, increased arterial blood temperature significantly. It is concluded that both fructose and glucose-induced thermogenesis occurs exclusively in extrasplanchnic tissues. Compared with glucose, fructose ingestion is accompanied by a more marked rise in CO2 production, possibly reflecting an increased extrasplanchnic oxidation of lactate and an accumulation of heat in the body.

scholarly journals STUDIES ON THE INTERACTION BETWEEN PHAGOCYTES AND TUBERCLE BACILLI

1956 ◽  
Vol 104 (1) ◽  
pp. 137-150 ◽  
Author(s):  
Hartmann Stähelin ◽  
Manfred L. Karnovsky ◽  
Emanuel Suter
Keyword(s):  
Carbon Dioxide ◽  
Bacillus Subtilis ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Guinea Pigs ◽  
Significant Degree ◽  
The Other ◽  
Polymorphonuclear Leucocytes ◽  
Mycobacterium Phlei

Tubercle bacilli labelled with C14 were prepared by growth on radioactive substrates such as glycerol, CO2, and acetate. These organisms were exposed in vitro to leucocytes (mostly polymorphonuclear leucocytes) from peritoneal exudates of guinea pigs. The respiration of the leucocytes and of the bacilli, alone and together, was followed by determining oxygen uptake and C14O2 production. When heat-killed labelled tubercle bacilli were exposed to leucocytes there was little or no degradation of bacillary material to C14O2 by leucocytic enzymes. On the other hand, conversion of components of sonically disrupted bacilli to C14O2 by leucocytes was significant. It was possible to determine the oxygen uptake and C14O2 production of phagocytized living tubercle bacilli, and it was found that after phagocytosis the bacilli maintained their rates of oxygen consumption and C14O2 production. This finding was in contrast to observations made with Mycobacterium phlei, a saprophytic acid-fast organism, and with Bacillus subtilis. In these cases oxygen consumption and C14O2 production declined after phagocytosis, and bacterial components were converted to carbon dioxide to a significant degree by leucocytic enzymes.

scholarly journals EFFECT OF ENZYME INHIBITORS AND ACTIVATORS ON THE MULTIPLICATION OF TYPHUS RICKETTSIAE

1948 ◽  
Vol 87 (3) ◽  
pp. 175-197 ◽  
Author(s):  
Donald Greiff ◽  
Henry Pinkerton
Keyword(s):  
Oxygen Consumption ◽  
Folic Acid ◽  
Oxygen Uptake ◽  
Enzyme Inhibitors ◽  
Potassium Cyanide ◽  
Host Cells ◽  
Cellular Respiration ◽  
Low Concentrations ◽  
Rate Of Oxygen Consumption ◽  
Respiratory Mechanism

A technique is described for measuring the oxygen uptake of embryonate eggs. Statistical analysis has shown that the method is reliable and accurate. Determinations were made on groups of 15 to 20 eggs, in order to average out individual biological variations. Reduction of the CO2 tension and relative humidity to approximately zero previous to analysis has been found to be desirable. The oxygen consumption of normal and typhus-infected eggs, untreated and treated with agents previously found to inhibit or enhance rickettsial growth has been studied. Rickettsial infection caused a slight but significant increase in the rate of oxygen consumption on the 4th day after inoculation, followed by a rapid drop in the rate as the infection developed. The evidence suggests that low concentrations of rickettsial toxins may stimulate respiration, while higher concentrations depress respiration and lead eventually to embryonic death. PABA, which is rickettsiostatic, markedly increased the oxygen uptake of normal eggs, the effect appearing 4 days after injection and lasting for about 4 days. Thereafter, the rate fell below that of the untreated eggs. In typhus-infected eggs, PABA had similar effects, but the oxygen consumption reached much higher levels. A possible explanation of this fact is suggested. MABA and OABA, which are not rickettsiostatic, did not increase oxygen uptake; in fact they depressed cellular respiration moderately, OABA being more active in this way than MABA. These two compounds may compete with PABA for a position in some respiratory enzyme system. Potassium cyanide, which enhances rickettsial growth, caused, in concentrations not lethal to the embryos, a moderate drop in the oxygen consumption of normal eggs, the effect starting almost immediately after injection and lasting usually for 9 days. In infected eggs, its effect was more striking. It is probable that rickettsial toxins and KCN act synergistically to depress cellular respiration. When PABA and KCN were injected simultaneously, the stimulating effect of PABA on respiration predominated. The resulting level of oxygen consumption, though lower than that resulting from PABA alone, was still high enough to inhibit rickettsial growth. As far as our results go, they support the hypothesis that, within certain limits, rickettsial growth is inversely proportional to the respiratory rate of the host cells, regardless of the factors which determine that rate. It is not yet clear that PABA owes its rickettsiostatic action to its ability to increase cellular respiration, but this assumption seems reasonable as a working hypothesis. The respiratory mechanism in which PABA participates is not as yet known. Although PABA forms part of the folic acid molecule, folic acid itself, in concentrations corresponding to effective doses of PABA, did not increase cellular respiration or show rickettsiostatic action.

Is Oxygen Consumption of Surviving Tissues Determined by the Oxygen Tension of the Suspension Medium?

1978 ◽  
Vol 33 (7-8) ◽  
pp. 511-516
Author(s):  
Josef Peter Pichotka ◽  
Hans Josef Schmidt
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Gas Phase ◽  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Fluid Phase ◽  
Tissue Samples ◽  
Suspension Medium ◽  
Measuring Period ◽  
Oxygen Tensions

Abstract Oxygen tension in the suspension medium and oxygen uptake of the isolated diaphragm of the mouse have been determined simultaneously with systematic variation of shaking frequency and oxygen concentration of the gas phase. Oxygen tension in the suspension medium readies its final value during the usual equilibration period of 10 minutes and remains constant for the whole measuring period. Each combination of shaking frequency and oxygen concentration of the gas phase results in a reproducible value of oxygen tension in the medium. Equal oxygen tension in the fluid phase can be attained by different combinations of shaking frequency and oxygen concentration of the gas phase. Oxygen uptake at the same oxygen tension of the suspension medium can be very different; it is the higher the higher the shaking rate in the combination. On the other hand the same oxygen consumption of the tissue samples can be observed with highly different oxygen tensions in the medium. It must be concluded from the data in this paper, that the influence of shaking rate per se on the oxygen uptake of isolated tissue can be of the same order as the influence of oxygen tension.

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