bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction Between Abdominal Ganglia During the Performance of Hormonally Triggered Behavioural Programmes In Moths
Authors: Truman James W. 
Published: April 2021

ABSTRACT
The isolated chain of four abdominal ganglia of Hyalophora cecropia has previously been shown to respond to the eclosion hormone by generating a pre-eclosion motor programme followed by the eclosion programme. Abdominal nervous systems reduced at any two ganglia could still generate both programmes. Selective addition of hormone to individual ganglia of the intact abdominal CNS resulted in the coordinated performance of both programmes by the entire CNS. In the eclosion programme, burst frequency was little influenced by which ganglion was exposed to hormone but in many cases the eclosion waves were initiated by the neurones in the treated ganglion rather than at the normal site in the terminal ganglion. When ganglia were removed from hormone-treated preparations during eclosion, the remainder of the chain showed a transient disruption in the bursting frequency but the frequency often eventually returned to pre-cut levels. Removal of anterior ganglia had no effect on the patterning of posterior bursts but removal of posterior ganglia resulted in a permanent reduction in the length of eclosion bursts in anterior ganglia. It was concluded that the information for both the pre-eclosion and eclosion programmes is patterned into each ganglion of the abdominal chain. For the pre-eclosion behaviour, the endogenous programme becomes pro-gressively longer in more posterior ganglia and each ganglion appears to have mutually exciting interactions with the other ganglia in the chain. In the intact animal the most anterior ganglion appears to drive the behaviour. By contrast, the eclosion behaviour also has segmental burst generators but they appear very similar in their properties. Each burst generator has an excitatory input on to the next anterior ganglion and inhibitory influences on posterior ganglia. Normally, the most posterior ganglion serves as driver for the eclo-sion behaviour.
Electrophysiology of Acanthocephalan Body Wall Muscles
Authors: Wong B. S. , Miller Donald M. , Dunagan T. T. 
Published: April 2021

ABSTRACT
Body wall muscles of an acanthocephalan Macracanthorhynchus hirudi- naceus were studied by means of scanning and light microscopy and intracellular recording of potentials. Three types of spontaneous potential changes were found: larger (L) potentials which usually exhibited overshoot and were as large as 65 mV; smaller symmetric (A) potentials approximately 15 mV in amplitude; and even smaller asymmetric (S) potentials which sometimes reached 10 mV. The potentials recorded depended upon the Position of the electrode in the anterior-posterior, as well as the medialateral, axis. Tetrodotoxin eliminated L but not S potentials. Ouabain lengthened the time for depolarization of L potentials and depolarized the membrane potentials. It is suggested that the rete system activates the body wall muscles in Acanthocephala.
Intrasegmental Proprioceptive Influences on the Period of the Swimmeret Rhythm in Crayfish
Authors: West Lani , Jacobs Gwen , Mulloney Brian 
Published: April 2021

ABSTRACT
When the swimmerets of decapods beat, they do so because the muscles of each swimmeret are driven by a series of periodic bursts of impulses in its motor neurones. We investigated the effects of proprioceptive feedback on the period of this motor pattern by interfering with the movement of particular swimmerets. In different experiments, we observed three different kinds of results during interference with a swimmeret. Either the period decreased, or it did not change, or bursting was inhibited altogether. These different results are discussed in terms of the connectivity of different command fibres.
Metabolic Sources of Heat and Power in Tuna Muscles
Authors: Hulbert W. C. , Guppy M. , Murphy B. , Hochachka P. W. 
Published: April 2021

ABSTRACT
As part of an investigation into the generation of muscle heat in the tuna, the histochemistry and ultrastructure of the myotomal muscles were studied. Both red and white fibres are differentiated into two forms. The two forms of red muscle are very similar except for differential electron absorbance and different kinds of glycogen granules stored. In both forms, capillarity, mitochondrial numbers, and intracellular lipid droplets are abundant, implying the potential for a vigorous aerobic metabolism. During bursts of swimming, glycogen granules and intracellular lipid droplets are both largely depleted. The two types of white fibre differ in electron absorbance, pinocyotic activity, glycogen abundance, and insertion pattern, all of which are more pronounced in the ‘dense’ fibre form. Several features of tuna white muscle are unique or unusually developed. Thus, tuna muscle contains more glycogen than does red muscle. Glycogen granules may be randomly dispersed in myofibrillar or peripheral regions or may be sequestered in membrane-bound structures termed glycogen bodies. During short bursts of swimming, glycogen granules from all storage sites are mobilized. The white muscle has an ample capillary supply, small, but significant, amounts of intracellular lipid, and unusual numbers of mitochondria.
Metabolic Sources of Heat and Power in Tuna Muscles
Authors: Guppy M. , Hulbert W. C. , Hochachka P. W. 
Published: April 2021

ABSTRACT
Tuna appear able to maintain their muscles at 5–10°C above ambient by balancing heat produced in situ and conserved by a counter-current heat exchanger with heat lost to the sea. Metabolite profiles under three different activity states (rest, burst swimming, and steady state swimming during feeding frenzies at sea) were used to identify which metabolic processes in white and red muscles could account for observed excess temperatures.
During burst swimming, transient changes in metabolite levels indicate that the metabolism of both red and white muscle contributes to powering burst swimming; red muscle work is sustained mainly by oxidative metabolism while white muscle work depends upon an intense anaerobic glycolysis. The rate of metabolism in red muscle is easily high enough to account for the measured (10 °C) increase in temperature at this time. However, in white muscle, anaerobic glycolysis can account for only about a 2 °C maximum rise in temperature.
The highest sustained swimming speeds and the highest muscle temperatures in skipjack are found during feeding frenzies at sea. As in burst swimming, during steady-state swimming red muscle temperatures can be accounted for by oxidative metabolism. In the case of white muscle, the lactate measurements indicate that anaerobic glycolysis could only lead to a 0·3 °C temperature rise. However, if the fraction of utilized glycogen that is not fermented (about 60 %) is assumed to be fully oxidized, enough heat is generated to raise white muscle temperatures by over 10 °C. The observed excess temperature at this time is about 8–10 °C, showing that areobic carbohydrate metabolism in white muscle is probably the major heat source during feeding frenzies.
These interpretations are fully consistent with enzyme profiles of red and white muscles in tuna. They do not, however, explain why tuna have warm muscles. The latter problem is briefly discussed.
Acid-Base Relationships in the Blood of the Toad, Bufo Marinus
Authors: Boutilier R. G. , Randall D. J. , Shelton G. , Toews D. P. 
Published: April 2021

ABSTRACT
Cutaneous CO2 excretion is reduced as the skin dries during dehydration but an increase in breath frequency acts to regulate the arterial blood and thus pHa. Moreover, the toad does not urinate and water is reabsorbed from the bladder to replace that lost by evaporation at the skin and lung surfaces. The animal does, however, produce a very acid bladder urine to conserve circulating levels of plasma [HCO3−] and this together with an increased ventilation effectively maintains the blood acid-base status for up to 48 h of dehydration in air. Water loss and acid production are presumably also reduced by the animal’s behaviour; animals remain still, in a crouched position or in a pile if left in groups.
Dehydrated toads are less able than hydrated toads to regulate blood pH during hypercapnia: they hyperventilate and mobilize body bicarbonate stores in much the same fashion as hydrated animals but due to the restrictions on cutaneous CO2 excretion and renal output, there is comparatively little reduction in the difference between arterial blood and inspired gas thereby resulting in a more severe respiratory acidosis. These factors further contribute to the persistent acidosis which continues even when the animals are returned to air.
Cation Accessibility of the Peripheral Nervous System in Limulus Polyphemus-An Electrophysiological Study
Authors: Willmer P. G. , Harrison J. Barrie 
Published: April 2021

ABSTRACT
The nervous systems of many vertebrates, and of some invertebrate phyla, are known to possess a ‘blood-brain barrier’ conferring a selective impermeability to certain ionic and molecular constituents of the body fluids and thus protecting the excitable membranes within a relatively constant micro-environment; this subject has been recently reviewed by Abbott & Treherne(1977). In vertebrates the barrier may be a property of the tight junctions between capillary endothelial cells (Brightman & Reese, 1969). Similarly in insects, at least to the level of the large peripheral nerves, electrophysiological evidence (Treherne et al. 1970; Treherne, 1974) and fine- structural studies (Lane & Treherne, 1972; Lane, 1972) indicate the existence of a barrier preventing free diffusion, residing in the tight junction complexes of the perineurium. However, investigations of crustacean nervous systems (Abbott, 1970; Abbott, Moreton & Pichon, 1975) show rapid access of ions to the peripheral nerves, but a delayed entry to the central nervous tissue that may be related to gap junctions and/or to maculae occludentes between the perineurial sheath cells (Lane & Abbott, 1975). An analogous situation may occur in some gastropod molluscs, where a partial ‘neurone-haemolymph barrier’ has been described (Reinecke, 1976), though in many members of this phylum the nervous tissue is freely accessible to ions (Sattelle & Lane, 1972; Willmer, 1978).
A Differential Volumetric Micro-Respirometer For Use With Small Aquatic Organisms
Authors: Dixon D. R. 
Published: April 2021

ABSTRACT
A micro-respirometer is described for use with small aquatic organisms whose rates of oxygen consumption fall within the range 0·1–5 μ l O2 h−1. The major design improvement which this apparatus has over existing models (e.g. Fenn, 1927) is a relatively large capillary bore. Kok, Veltkamp & Gelderman (1953) having shown a proportional decrease in the sensitivity of volumetric respirometers with capillaries smaller than 1 mm diameter. The most recent treatment of the theoretical aspects of differential respirometry is by Umbreit, Burris & Stauffer (1972).
Ionic Permeability of the Blood-Brain Barrier System of An Insect Carausius Morosus
Authors: Schofield P. K. 
Published: April 2021

ABSTRACT
Large ionic gradients must be maintained across the blood-brain barrier system of Carausius morosus, for the neurones are apparently conventional in their ionic requirements (Treherne & Maddrell, 1967; Weidler & Diecke, 1969) while the haemolymph has been found to contain ionic concentrations as adverse as 9 mm-Na, 28 mm-K and 73 mm-Mg (Duchateau, Florkin & Leclerq, 1953). The ionic permeability of the system is here examined in the manner of Pichon, Moreton & Treherne (1971), by observing changes in extraneuronal potential produced by an alteration in the ionic composition of the saline bathing the first pair of thoracic connectives (from adults) from which the fat-body sheath had been removed. (The fat body has been shown to be a relatively leaky structure: Lane & Treherne, 1971; Treherne, 1972.)
Optomotor Control of Speed and Height by Free-Flying Drosophila
Authors: David C. T. 
Published: April 2021

ABSTRACT
The optomotor reactions of Drosophila have been studied intensively, with the conclusion that in flight there are two main types of response. One of these controls the course of the animal by adjusting the relative amplitudes of the wingbeats on the two sides of the body. The other controls the total thrust produced by the wings (Gotz, 1968). Drosophila do not change the direction of the thrust produced relative to the body axis (Gotz, 1968; Vogel, 1966; David, 1978) but do change the distribution of their total power output between lift and thrust by changing the inclination of the body axis (David, 1978). This could not, however, be observed in tethered fliers on which previous work had been done. Nevertheless, it has been implied that free fliers alter only their lift, so that the control of power output is used only to control height (Gotz, 1972; Buchner, Gotz & Straub, 1978). Here I report some experiments on free-flying Drosophila hydei Sturtevant showing that speed (and hence thrust) as well as height (and hence lift) are controlled by optomotor reactions to features of the surroundings.
Permeability and Active Transport in Malpighian Tubules
Authors: Fletcher C. R. 
Published: April 2021

ABSTRACT
In a paper on regional specialization in the lower Malpighian tubule of Rhodnius prolixus, Maddrell (1978) reported that active recovery of potassium chloride from the tubular fluid is confined to the lowest region of the tubule, and is inducible by 5-HT. He also reported that the gross influx of potassium, measured by movement of K42 from the bathing solution into the lumen, shows a 200-fold stimulation by 5-HT in this part of the tubule, but not in the non-transporting region. He could not explain the effect.
The Refractive Index Gradient in the Crystalline Cones of the Eyes of A Euphausiid Crustacean
Authors: Land M. F. , Burton F. A. 
Published: April 2021

ABSTRACT
The eyes of the euphausiids, a group of malacostracan Crustacea, show a remarkable similarity to the superposition (Exner, 1891) eyes of moths. In both groups the eye has an outer layer of crystalline cones, a wide clear zone, and a layer of rhabdomes beneath it, whose radius of curvature is about half that of the eye itself (Fig. 2 a). We demonstrated recently that image formation in these eyes is indeed performed by a refracting superposition mechanism (Land, Burton & Meyer-Rochow, 1979), as supposed by Chun (1896). That is to say, light is bent by the crystalline cones in such a way that a ray reaching the outer surface of a cone, and making an angle α with the cone axis, is bent in the cone through an angle 2α (Fig. 1). This is the condition necessary if all parallel rays are to be brought to a focus in the rhabdome layer, where an erect image is produced (see Horridge, 1975). This mechanism, shared by moths, fireflies and some other beetles, is not the same as that of the decapod shrimps and prawns, where essentially the same trick is performed not by refracting cones, but by mirrors (Vogt, 1977; Land, 1978). Kampa (1965) proposed that the euphausiid eye was basically of the apposition type, with the cones funnelling light down light guides into the rhabdomes. However, the cones send light, as noted above, and the light-guides are not present (Meyer-Rochow & Walsh, 1979).
Phase Co-Ordination in the Cardiac and Ventilatory Rhythms of the Lobster Homarus Americanus
Authors: Young Ronald E. , Coyer P. E. 
Published: April 2021

ABSTRACT
Relative co-ordination is demonstrated between the rhythms of the right and left scaphognathites (SG) and between the heart and either right or left SG or both simultaneously. The co-ordination between these rhythms results from mutual phasedependent alteration of the period lengths as demonstrated by the phaseresponse curves for the interactions. The standard deviation of the SG period lengths is an inverse linear function of the percentage coupling between the two SGs (r = 0·76; P &lt; 0·01). The right SG motor output may show relative co-ordination with respect to a sinusoidal, dorso-ventral movement applied along the radial axis of that appendage. This is taken to indicate that sensory reafference resulting from the interplay between the applied and intended movements can alter the SG rhythm depending upon the relative phasing of the two movements. The effects of sensory reafference are therefore not merely tonic as has been believed until now. Cautery of the right oval organ, a major phasic mechanoreceptor of the SG, has no significant influence on any of the above relationships. The significance of this and of the widespread occurrence of relative co-ordination between rhythmic activities is discussed.
Calcium Regulation in Intermoult Gammarus Pulex
Authors: Wright D. A. 
Published: April 2021

ABSTRACT
The compartmentation of calcium was studied in adult intermoult Gammarus pulex. The total body calcium concentration was 547 µmol g. wet wt.−1, which is weight for weight approximately one half of the calcium concentration found in decapod crustaceans. Over 96% of whole body calcium in G. pulex was found in the exoskeleton.
45Ca exchange curves for haemolymph and hepatopancreas had similar time constants indicative of a comparatively large pool of freely exchangeable calcium. The parallel exchange of calcium between the haemolymph and other soft tissue compartments confounded the satisfactory use of an algebraic model for indirect calcium influx measurement using haemolymph specific activity. All calcium influx was subsequently measured on a whole-body basis.
Passive absorption of calcium on to the cuticle was eliminated as a significant factor as the metabolic inhibitor 2:4-DNP almost completely inhibited any form of calcium uptake. The active nature of the calcium regulatory mechanism was further illustrated by potential difference measurements indicating that calcium is accumulated against an electrochemical gradient from media having a calcium activity less than 1 mmol 1−1.
When placed in calcium-free media, intermoult Gammarus pulex are able to achieve at least a tenuous calcium balance between 12 and 50 µmol Ca l−1 at a density of 1 animal per 10 ml medium. Some specimens show a slow calcium loss. The calcium regulatory mechanism is saturated at an external calcium concentration of 2 mmol l−1, which is the normal field calcium concentration for this population, and has a half saturation value of 0·3 mmol l−1.
Electrical Recording from the Contractile Ciliate Zoothamnium Geniculatum Ayrton
Authors: Moreton R. B. , Amos W. B. 
Published: April 2021

ABSTRACT
The spherical body (200 μm in diameter) of this ciliate protozoan was easily immobilized on a suction pipette and penetrated with glass microelectrodes. No recordings could be made from the contractile stalk, but in the body a negative potential of 30· 3 ± 12· 5 mV was observed. Approximately 9 ms after the onset of a mechanical stimulus, a rapid depolarization was observed. This was apparently simultaneous throughout the body surface. The amplitude was 38· 9 ±13· 7 mV. Recordings with a photomultiplier showed that contraction of the stalk began 10 ms later. A slower depolarization of complex form was observed during systole of the contractile vacuole.
Ionic Regulation in Rainbow Trout (Salmo Gairdneri) Adapted to Fresh Water and Dilute Sea Water
Authors: Eddy F. B. , Bath R. N. 
Published: April 2021

ABSTRACT
Small rainbow trout (5-20 g) adapt to salinities of up to at least 22%o but not to full strength sea water. In adapted fish plasma ions are regulated near the fresh water values, but there is an ionic invasion of the tissues, particularly by Cl− in muscle cells. Analysis of ionic regulation in adapted fish indicates that balance is maintained mainly by expending energy on Cl− regulation. Fish in full strength sea water can no longer regulate Na+ or Cl− in plasma or tissues, which results in high tissue concentrations of these ions and eventual death.
Swimming Energetics of Striped Bass (Morone Saxatilis) and Bluefish (Pomatomus Saltatrix): Gill Ventilation and Swimming Metabolism
Authors: Freadman M. A. 
Published: April 2021

ABSTRACT
Striped bass and bluefish use cyclic ventilatory movements to accomplish gas exchange at rest and slow swimming speeds, whereas at intermediate and high velocities, both species routinely shift to ram gill ventilation. Metabolic characteristics of the shift in respiratory behaviour indicate that as an animal adopts the ram mode, energy expenditure departs from an exponential relationship and increases at a shallow rate over the next 15 cm. s−1 range in speed. At higher, ram-supporting velocities, oxygen uptake increases once again at an exponential rate. Similar determinations of oxygen uptake at imposed swimming velocities in hatchery-raised rainbow trout reveal an exponential relationship over the entire swimming range. Trout actively ventilate their gills over this velocity range as well. In striped bass, the requisite trans-gill pressure for ram ventilation, as developed between the mouth and opercular door margins, is about 0·5 cm H2O. Critical swimming velocities for striped bass are 2·9–3·3 bl.s−1 while bluefish can maintain station at 4·0–4·6 bl.s−1. The adoption of ram gill ventilation is a velocity-dependent phenomenon over the size-range tested. Transfer of the work load of ventilation from the branchial to the swimming musculature results in substantial metabolic savings well within the cruising ranges of striped bass and bluefish. The savings probably accrue from cessation of rhythmic pumping by the branchial musculature and a change in overall body drag at ram-supporting swimming speeds.
Mechanism of Inhibition of Active Potassium Transport in Isolated Midgut of Manduca Sexta by Bacillus Thuringiensis Endotoxin
Authors: Harvey William R. , Wolfersberger Michael G. 
Published: April 2021

ABSTRACT
After incubation at pH 10 or higher, Bacillus thuringiensis spores and endotoxin, at concentrations above 0·1 lU/ml, affected transport parameters in the isolated midgut of Manduca sexta larvae. (Toxic activity was lost during roughly 1 week at pH 11.) About 60% of the short-circuit current was inhibited, and the remainder was reversibly inhibited by anoxia. Electrical resistance was reduced by about 55% and oxygen uptake stimulated by about 30%. Influx of potassium from blood-side to lumen-side (‘active’ flux) was unaffected but flux in the reverse direction was nearly tripled. These results suggest that hydrolysis of the toxin yields an inhibitor of potassium transport, presumably a polypeptide. It is argued that inhibition is not primarily by uncoupling of oxidative phosporylation, but instead by interference with an active depression of the efflux of potassium from lumen-side to blood-side.
The Effects of Oxygen Supply, Epinephrine, and Acetylcholine On the Distribution of Blood Flow in Trout Gills
Authors: Booth John H. 
Published: April 2021

ABSTRACT
Injecting vitally stained blood cells into the ventral aorta of unrestrained, cannulated fish, and rapid freezing in liquid nitrogen, permitted the examination of the effects of oxygen supply, epinephrine and acetylcholine on branchial lamellar perfusion. Compared to the conditions in resting fish in air-saturated water, hypoxia and injection of epinephrine significantly increased the proportion of secondary lamellae receiving stained cells, and acetylcholine caused a significant reduction, but hyperoxia did not significantly affect the proportion of lamellae containing stained cells. Perfusion of the filamental central compartment was not affected by the treatments. It is concluded that trout can respond to changes in oxygen supply by varying the number of secondary lamellae perfused with blood, and that the distribution of blood flow is regulated by cholinergic and adrenergic receptors. It is suggested, however, that lamellar recruitment would not be useful in minimizing the costs of osmo- and iono-regulation.