... wherein fish from normoxia ( N =24) were exercised in swim tunnels in both hypoxia (40%, n =12) and normoxia (100%, n =12) conditions, and likewise for hypoxia-exposed fish ( n =10 in each group). Oxygen consumption, critical swim speed ( U crit ), critical oxygen threshold ( P crit ) and mitochondrial...

... to adult form. In holometabolous insects this transition is ostensibly initiated at the attainment of a critical weight in the final larval instar. It has been hypothesized that the size-sensing mechanism used to determine attainment of critical weight exploits oxygen limitation as a larvae grows beyond...

... of Hb–O 2 affinity, changing the overall oxygenation enthalpy (Δ H ′) values of opah (10–20°C) and swordfish (10–25°C) Hbs at pH 7.4 from −15 and −42 kJ mol −1 O 2 , respectively, to +84 and −9 kJ mol −1 O 2 . Swordfish blood–O 2 affinity was high compared with that of other large, pelagic, marine...

... ever before. Aquatic respirometry measures the rate of oxygen uptake as a proxy for metabolic rate, and the intermittent-flow technique has numerous strengths for use with aquatic animals, allowing metabolic rate to be repeatedly estimated on individual animals over several hours or days and during...

... dioxide governs the oxygen affinity of crocodile blood . Nature 269 , 825 - 827 . 10.1038/269825a0 Bauer , C. and Schröder , E. ( 1972 ). Carbamino compounds of haemoglobin in human adult and foetal blood . J. Physiol. 227 , 457 - 471 . 10.1113/jphysiol.1972.sp010042...

... , and aimed to determine whether individual oxygen demand influenced the behaviour of entire groups. Groups of seven fish were observed in an arena to measure air-breathing frequency of individuals and consequent group air-breathing behaviour, under three oxygen concentrations (100%, 60% and 20% air...

...Gigi Y. Lau; Sabine Arndt; Michael P. Murphy; Jeffrey G. Richards ABSTRACT Animals that inhabit environments that fluctuate in oxygen must not only contend with disruptions to aerobic metabolism, but also the potential effects of reactive oxygen species (ROS). The goal of this study was to compare...

... of reactive oxygen species (ROS) after prolonged anoxia, but the mechanisms are unclear. Here, we investigated whether this mitochondrial suppression originates from downregulation of mitochondrial content or intrinsic activity by comparing heart mitochondria from (1) warm (25°C) normoxic, (2) cold-acclimated...

...Jules B. L. Devaux; Anthony J. R. Hickey; Gillian M. C. Renshaw ABSTRACT Exposure to anoxia leads to rapid ATP depletion, alters metabolic pathways and exacerbates succinate accumulation. Upon re-oxygenation, the preferential oxidation of accumulated succinate most often impairs mitochondrial...

...Matthew A. Birk; Agnieszka K. Dymowska; Brad A. Seibel ABSTRACT Squid are thought to obtain a large portion of their oxygen via simple diffusion across the skin in addition to uptake at the gills. Although this hypothesis has support from indirect evidence and is widely accepted, no empirical...

... examined alternative paths of gas exchange in sea spiders: (1) oxygen diffuses across pores in the cuticle, a common mechanism in terrestrial eggshells, (2) oxygen diffuses directly across the cuticle, a common mechanism in small aquatic insects, or (3) oxygen diffuses across both pores and cuticle. We...

... of dissolved oxygen (20%, 100% and 150% saturation), dissolved carbon dioxide (9.5 and 19.1 µmol l −1 ) and water flow (1–1.6 versus 4–13 cm s −1 ) in a repeated measures design. Dark respiration was enhanced by increased flow and increased oxygen saturation in an interactive way, which relates to improved...

... a morphometric model of the canal system, we also show that filter feeding may be more energetically costly than previously thought. Measurements of volumetric flow rates and oxygen removal in five species of demosponge show that pumping rates are variable within and between species, with the more oxygen...

...H. Arthur Woods; Steven J. Lane ABSTRACT Many terrestrial insects live in environments that flood intermittently, and some life stages may spend days underwater without access to oxygen. We tested the hypothesis that terrestrial insects with underground pupae show respiratory adaptations...

... that DGCs are terminated as a result of inadequate oxygen supply to the tissues. * Authors for correspondence ( [email protected] ; [email protected] ) Competing interests The authors declare no competing or financial interests. 8 6 2015 2 10 2015 © 2015...

... Optode Oxygen Respiration Spiracle Tracheal system Insects rely primarily on their tracheal system to exchange respiratory gases with the atmosphere ( Wigglesworth, 1931 ). The system consists of air-filled tubes that open to the air through spiracles on the surface of the thorax and abdomen...

...Lutz T. Wasserthal Respiration in insects is thought to be independent of the circulatory system because insects typically lack respiratory pigments and because oxygen transport occurs in the gaseous phase through a ramified tracheal system by diffusion and convection directly to the tissues...

...D. J. Randall; J. L. Rummer; J. M. Wilson; S. Wang; C. J. Brauner Teleost fishes constitute 95% of extant aquatic vertebrates, and we suggest that this is related in part to their unique mode of tissue oxygenation. We propose the following sequence of events in the evolution of their oxygen...

...) the physiology of marine invertebrates. Hypoxia occurs in marine systems when substantial biological O 2 demand and restricted water movement co-occur. It is a natural feature of enclosed (e.g. rock pools, sediments), semi-enclosed (e.g. poorly mixed fjords) or seemingly open (e.g. the oxygen minimum zone...

...Viviane Callier; Alexander W. Shingleton; Colin S. Brent; Shampa M. Ghosh; Jinkyu Kim; Jon F. Harrison SUMMARY Rearing oxygen level is known to affect final body size in a variety of insects, but the physiological mechanisms by which oxygen affects size are incompletely understood. In Manduca sexta...