bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactions of Daphnia to Simultaneous Light and Electrical Stimuli
Authors: Robertson J. A. 
Published: April 2021

ABSTRACT
Experiments were carried out with Daphnia to see whether the phototropism and galvanotropism which they exhibit would, when the animals were exposed simultaneously to light and to electric current at right angles to each other, induce a resultant reaction such as occurs in many phototropic animals when exposed to two sources of light simultaneously.
Considering the rather difficult nature of the material (consequent on the number of small specimens present, the prevalence of quiescence or inhibition, and the all too frequent modifiability and variability of behaviour among some individuals in the cultures), the following results may, I think, be seen sufficiently clearly: A resultant reaction in the large specimens, doubtfully in the small ones; positivation, by the current, of the photonegative large specimens, but not of the small animals ; kathodic galvanotropism in the large, but not in the small individuals. The threshold value of the current, for galvanotropic reaction alone, and for resultant reaction and positivation, has been found; and finally the latter threshold value has been shown to be independent of the light intensity. The current threshold for resultant reaction, with the light intensities tried, is seen to be the same as that for kathodic galvanotropism alone.
Gonad Grafts in the Fowl
Authors: Greenwood A. W. 
Published: April 2021

ABSTRACT
A histological examination has been made of material from 19 cases of gonad grafts in fowls, from the series of transplantation experiments performed by G. F. Finlay. While some of the ovary grafts remain typically ovarian in structure, many show extensive changes due to a secondary proliferation of the sex cords and their further differentiation into tubules of a definitely spermatic type. Most of the testis grafts are either in active spermatogenesis or are composed of an intimate mixture of active and atrophic tubules ; in 2 cases they consist of atrophic tubules only. It is suggested that the formation of atrophic tubules may be due, apart from environmental conditions, to mechanical pressure. Islets of typical “luteal” cells are present in the interstices between the inactive tubules in the testis grafts, and are not associated with a henny type of plumage. In ovarian grafts “luteal” tissue is found in the thecæ of the follicles, as in the normal ovary, and also in the region of undifferentiated sex cord tissue and tubules. It has not been possible exactly to determine the origin of the new proliferation of the sex cords in the ovarian grafts. It would appear that they may be derived from the germinal epithelium and also from the intra-ovarian epithelial elements represented by the degenerating medullary cords. There appears to be some time relation involved in the formation of the secondary proliferation of the sex cords in the ovarian grafts, since (with one exception) none are found in grafts made later than the fourth day after hatching. Two cases of an activated right gonad in the ovariot-omised female are described, of which one shows typical ovarian structure. The hypothesis is put forward that the right gonad is female fundamentally in constitution, and if it differentiated under a specific stimulus (normally characteristic of the female chick at an early stage of incubation but exceptionally reproduced at a later stage in development) an ovary would be formed.
The Respiration of Tyroglyphus Farinae
Authors: Hughes T. E. 
Published: April 2021

ABSTRACT
This investigation into the reactions of Tyroglyphus farinae to varying concentrations of carbon dioxide and oxygen and to the presence of small quantities of hydrocyanic acid, was carried out in order to obtain some insight into the respiratory activities of the mite, very little being known of its physiological reactions. As a necessary preliminary, its reactions to humidity were determined. T. farinae belongs to the family Tyro-glyphidae and respires by direct diffusion through the body surface, since no tracheae are present. These mites infest stored food material, being found on grain, flour and meal. They are associated with the micro-organisms of decay and it might be expected that the gaseous conditions under which they live differ considerably from those of ordinary air. It was decided, therefore, to isolate cultures and to investigate the gaseous changes produced by the organisms in the culture and the effect of such changes on the mites present. The respiratory quotient in normal air was also determined, together with the quotient obtained in the presence of an M/1000 solution of potassium cyanide. The reactions of the mite to varying concentrations of carbon dioxide, oxygen and water vapour in the atmosphere were also determined.
The Absorption of Sodium Ortho-Iodo-Hippurate from the Rumen of Lambs
Authors: Barcroft J. , Mcanally R. A. , Phillipson A. T. 
Published: April 2021

ABSTRACT
Previous work (Phillipson & McAnally, 1942) indicates that absorption from the rumen is not only possible, as was shown by Trautmann (1933), but is rapid enough to prevent passage to the abomasum of volatile acid present in the rumen, although these acids are present in the rumen in a high concentration. This evidence is remarkable, as the epithelium lining the rumen is stratified and squamous qualities not usually associated with membranes through which there is active absorption.
The Biology and Behaviour of Ptinus Tectus Boie (Coleoptera, Ptinidae), A Pest of Stored Products
Authors: Bentley E. W. 
Published: April 2021

ABSTRACT
Ptinus tectus adults react to a humidity gradient by collecting in the drier region. The reaction to a given difference of humidity is most intense at low humidities; it declines to nothing at about 75-90% R.H. and increases again at 90-100% R.H. No such variation has previously been found. A kinetic mechanism of reaction is involved. The higher the humidity the higher the locomotory activity over a period of a week. Desiccated animals are more active than normal ones. At low humidities they show a much weakened reaction towards drier air; at high humidities the normal reaction is reversed and the animals collect in the wetter region. Desiccated animals given water to drink immediately begin to behave like normal ones. Some of the humidity receptors appear to be located on the antennae. Removal of the distal joint increases the intensity of reaction in high humidities, but the interpretation of this is questionable. The reaction remains strong when up to five joints are amputated and then it declines. When only one or more of the last three joints remain, a reversed reaction occurs, similar to that shown by desiccated individuals. This suggests that there are two kinds of humidity receptors, the first kind being mainly located distally on the antennae and some of the second kind being either on the basal joint or not on the antennae at all. Attempts to identify humidity receptors were not successful.
The Water Relations of Snails and Slugs
Authors: Wells G. P. 
Published: April 2021

ABSTRACT
If H. pomatia are kept under conditions of constant temperature, humidity, illumination, food supply and water supply, their daily weight curves show great spontaneous fluctuations of an irregularly cyclical character, with a period of several days. Snails kept without food, but under otherwise identical conditions, show similar fluctuations of smaller amplitude (Fig. 1). A number of measurements of the oxygen consumption of H. pomatia were made at different points on the weight cycle. In fed animals, oxygen consumption tends to rise with weight. In fasting animals, the relationship between the two variables is less marked, and the oxygen consumption is always low (Figs. 2, 3). Aestivation tends to occur, even if environmental conditions are favourable, whenever the weight is low (Fig. 4). Feeding and digestion are apparently confined to the weight peaks, and incompatible with aestivation. The interrelations of internal and external factors in determining the activity level of H. pomatia are discussed. In drought, the activity outbursts are inhibited and the snail remains withdrawn, with low weight and oxygen consumption. Rain, after drought, releases the cycles again; the immediate mechanism of activation is not hydration of the tissues, but a stimulation effect.
Quantitative Analysis of Jaw and Hyolingual Muscle Activity During Feeding in the Lizard Agama Stellio
Authors: Herrel Anthony , Cleuren Johan , Vree Frits De 
Published: April 2021

ABSTRACT
The activity of jaw and hyolingual muscles during the entire feeding sequence is examined in the lizard Agama stellio, with special focus on the intraoral transport and swallowing stages. Correlation of electromyography (EMG) data with kinematics shows that the kinematic phases (slow opening, SO; fast opening, FO; fast closing, FC; slow closing/power stroke, SC/PS) are characterised by distinct activities in the jaw and hyolingual muscles. The SO phase is clearly the result of tongue protraction (upon protraction, the tongue is pulled against the prey and consequently the lower jaw is pushed down), whereas the FO phase is caused by activity in the jaw opener and dorsal cervical muscles. Both the FC and SC/PS phases are characterised by pronounced activity in the jaw adductor muscles. Tongue retraction is produced by activity in the hyoid and tongue retractor muscles. A quantitative analysis of time-related EMG data shows that, in accordance with the kinematic analyses, three different stages can be recognised as components of the feeding cycle: prey capture, intraoral transport and swallowing. However, analysis of intensity-related data allowed a fourth stage, crushing, to be detected. Whereas there are indications that prey capture, intraoral transport and swallowing are controlled by different motor patterns, the differences between crushing and transport are likely to be caused by feedback mechanisms. Our results show the importance of including intensity-related data in quantitative analyses of EMG recordings in order to discriminate between feeding stages. Additionally, it is shown that both the jaw and the hyolingual muscles play crucial roles during feeding. During all stages, movements of the hyolingual apparatus are an essential part of the feeding cycle. Thus, when examining lizard feeding mechanisms, the activity patterns of the hyolingual muscles should not be neglected.
Correlation Between Changes in Host Behaviour and Octopamine Levels in the Tobacco Hornworm Manduca Sexta Parasitized by the Gregarious Braconid Parasitoid Wasp Cotesia Congregata
Authors: Adamo Shelley A. , Linn Charles E. , Beckage Nancy E. 
Published: April 2021

ABSTRACT
The parasitoid wasp Cotesia congregata lays its eggs within the body of its host, the larval form of the tobacco hornworm Manduca sexta. Host behaviour appeared normal until approximately 8 h prior to the emergence of the parasitoids from their host at which time M. sexta feeding and locomotion declined irreversibly. This change in host behaviour may be to the advantage of the wasp since unparasitized M. sexta presented with wasp pupae ate them. Despite the decline in feeding and locomotion, hosts with emerged parasitoids had normal reflexes and showed no other signs of debilitation. Concomitant with the change in host behaviour, octopamine concentration measured using high-performance liquid chromatography with electrochemical detection (HPLC-ED) increased from 22.2±2.1 pg μl−1 to 143.7±7.8 pg μl−1 in the haemolymph of the host. In unparasitized M. sexta, however, increased octopamine levels were correlated with increased activity. We discuss possible explanations for the co-occurrence of high haemolymph octopamine levels and low behavioural arousal in parasitized M. sexta.
K+ REABSORPTION BY THE LOWER MALPIGHIAN TUBULE OF RHODNIUS PROLIXUS: INHIBITION BY Ba2+ AND BLOCKERS OF H+/K+-ATPases
Authors: Haley Charlene A. , O’Donnell Michael J. 
Published: April 2021

ABSTRACT
Active K+ reabsorption by the lower Malpighian tubule of the blood-feeding hemipteran Rhodnius prolixus does not involve the amiloride-sensitive K+/H+ exchangers or V-type H+-ATPases implicated in secretion of ions from haemolymph to lumen in the upper tubule. Amiloride, N-ethylmaleimide, 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol and bafilomycin A1 inhibit haemolymph-to-lumen secretion of Na+ and K+ by the upper Malpighian tubule, but have little or no effect on lumen-to-haemolymph reabsorption of K+ by the lower tubule. The effects of inhibitors of H+/K+-ATPases, including omeprazole and SCH 28080, suggest that a pump similar to the H+/K+-ATPase of the gastric mucosa is involved in KCl reabsorption. The presence of K+ channels in the basolateral membrane in the lower Malpighian tubule is suggested by inhibition of KCl reabsorption by basolateral but not apical application of the K+ channel blocker Ba2+, and by blockade of K+-dependent changes in membrane potential by Ba2+. It is proposed, therefore, that K+ is pumped from lumen to cell by an ATP-dependent pump resembling the H+/K+-ATPase of the gastric mucosa, and that K+ leaks from cell to bathing saline (haemolymph) via an electrodiffusive pathway (i.e. K+ channels).
Prey Ingestion Revealed By Oesophagus And Stomach Temperature Recordings In Cormorants
Authors: Ancel A. , Horning M. , Kooyman G. L. 
Published: April 2021

ABSTRACT
We examined the accuracy of both stomach and oesophagus temperature sensors – deployed on captive Brandt’s cormorants – for determination of the mass of food ingested and the number of prey items swallowed. The oesophageal temperature sensor was a better detector of all feeding events, including that of small prey which were missed by the stomach sensor. Adapted to free-ranging animals (and coupled to data loggers for recording seawater temperature), oesophagus temperature recorders, in conjunction with both recordings of energy expenditure (e.g. doubly labelled water, heart rate) and determination of position (e.g. Argos transmitter, time/depth recorder), should provide further important insights into the foraging success of marine endotherms.
Extracellular Carbonic Anhydrase and an Acid–Base Disequilibrium in the Blood of the Dogfish Squalus Acanthias
Authors: Gilmour K. M. , Henry R. P. , Wood C. M. , Perry S. F. 
Published: April 2021

ABSTRACT
The electrometric ΔpH method and an in vitro radioisotopic HCO3− dehydration assay were used to demonstrate the presence of true extracellular carbonic anhydrase (CA) activity in the blood of the Pacific spiny dogfish Squalus acanthias.
An extracorporeal circulation and stopflow technique were then used to characterise the acid–base disequilibrium in the arterial (postbranchial) blood. During the stopflow period, arterial pH (pHa) decreased by 0.028±0.003 units (mean ± S.E.M., N=27), in contrast to the increase in pHa of 0.029±0.006 units (mean ± S.E.M., N=6) observed in seawater-acclimated rainbow trout Oncorhynchus mykiss under similar conditions. The negative disequilibrium in dogfish blood was abolished by the addition of bovine CA to the circulation, while inhibition by benzolamide of extracellular and gill membrane-bound CA activities reversed the direction of the acid–base disequilibrium such that pHa increased by 0.059±0.016 units (mean ± S.E.M., N=6) during the stopflow period. When the CA activity of red blood cells (rbcs) was additionally inhibited using acetazolamide, the magnitude of the negative disequilibrium was increased significantly to −0.045±0.007 units (mean ± S.E.M., N=6). Blockage of the rbc Cl−/HCO3− exchanger using 4,4′-diisothiocyanostilbene-2,2′-disulphonic acid (DIDS) also increased the magnitude of the negative disequilibrium, in this case to −0.089±0.008 units (mean ± S.E.M., N=6). Exposure of dogfish to hypercapnia had no effect on the disequilibrium, whereas the disequilibrium was significantly larger under hypoxic conditions, at −0.049±0.008 units (mean ± S.E.M., N=6).
The results are interpreted within a framework in which the absence of a positive CO2 excretion disequilibrium in the arterial blood of the spiny dogfish is attributed to the membrane-bound and extracellular CA activities. The negative disequilibrium may arise from the continuation of Cl−/HCO3− exchange in the postbranchial blood and/or the hydration of CO2 added to the plasma postbranchially. Two possible sources of this CO2 are discussed; rbc CO2 production or the admixture of blood having ‘low’ and ‘high’ CO2 tensions, i.e. the mixing of postbranchial blood with blood which has bypassed the respiratory exchange surface.
cDNA Cloning of Myosin Heavy Chain Isoforms From Carp Fast Skeletal Muscle and Their Gene Expression Associated With Temperature Acclimation
Authors: Imai Jun-Ichi , Hirayama Yasushi , Kikuchi Kiyoshi , Kakinuma Makoto , Watabe Shugo 
Published: April 2021

ABSTRACT
We have isolated cDNA clones encoding fast skeletal muscle myosin heavy chains of carp acclimated to 10, 20 and 30 °C for over 5 weeks. All clones covered at least the full length of L-meromyosin, the C-terminal part of the myosin molecule. Nucleotide sequence analysis on cDNA clones showed three types of 3′ untranslated sequences, demonstrating that carp expresses at least three myosin heavy chain isoforms in fast skeletal muscle in an acclimation-temperature-dependent manner. cDNAs were identified which were the predominant types expressed in 10 °C-and 30 °C-acclimated fish, as well as an intermediate type present at all acclimation temperatures. Northern blot analysis using probes of three kinds of DNA fragments from the 3′ untranslated region of carp acclimated to 10, 20 and 30 °C further confirmed the presence of acclimation-temperature-specific isoforms. In addition, it was found that mRNA levels of three isoforms were altered in an acclimation-temperature-dependent manner. When the deduced amino acid sequences of three types of carp L-meromyosin were compared with those of homoiotherms, the 30 °C-acclimated type was more similar to those of homoiotherms than was the 10 °C-acclimated type.
A Kinematic Analysis of Tentacle Extension in the Squid Loligo Pealei
Authors: Kier William M. , Leeuwen Johan L. Van 
Published: April 2021

ABSTRACT
High-speed ciné recordings of prey capture by the squid Loligo pealei were used to analyze the kinematics of the rapid tentacular strike. The proximal portion of the tentacle, the stalk, elongates during the strike. The non-extensible distal portion of the tentacle, the club, contacts the prey and attaches using suckers. Seven sequences of prey capture filmed at 750 frames s−1 were analyzed frame by frame. The positions of the head, the tentacles and the prey were digitized, and the data were smoothed using quintic natural B-splines and the generalized cross-validation (GCV) criterion. During the strike, the animal swims forward at velocities ranging from 0.7–1.2 m s−1, and as the eight arms are flared, the tentacular stalks elongate. Tentacular extension occurred in approximately 20–40 ms with peak strains in the tentacular stalk ranging from 0.43–0.8. Peak longitudinal strain rates varied from 23–45 s−1. Maximum extension velocities of the stalk were calculated to be over 2 m s−1 with peak accelerations of approximately 250 m s−2. Once the tentacular clubs have contacted the prey, the tentacular stalks are frequently observed to buckle.
D-Glucose-Sensitive Neurosecretory Cells of the Crab Cancer Borealis and Negative Feedback Regulation of Blood Glucose Level
Authors: Glowik Regina M. , Golowasch Jorge , Keller Rainer , Marder Eve 
Published: April 2021

ABSTRACT
We studied the effects of glucose on cultured X-organ neurons of the crab Cancer borealis using single-electrode current- and voltage-clamp techniques. A subpopulation of the cells responded to D-glucose with a hyperpolarization. These cells, but not glucose-insensitive cells, showed immunoreactivity to crustacean hyperglycemic hormone (CHH), the hormone responsible for the elevation of blood glucose levels in crustaceans. Glucose-sensitive cells were also inhibited by serotonin and γ-aminobutyric acid but were not affected by dopamine and Leu-enkephalin. The response was specific for D-glucose, with an EC50 of 0.25 mmol l−1. No response was seen to L-glucose, sucrose, galactose, mannose or fructose. The glucose response persisted in the absence of extracellular Na+ and in low-Ca2+/Mn2+ saline. In voltage-clamp experiments, D-glucose evoked a small current with a reversal potential close to that of voltage-dependent K+ currents. We conclude that D-glucose activates a K+ current in CHH-immunoreactive cells that, in normal saline, induces a hyperpolarization. We propose that this enables glucose to regulate directly the release of CHH into the hemolymph, thus constituting a negative feedback mechanism regulating hemolymph glucose concentration.
Vestibular Compensation in Lampreys: Impairment and Recovery of Equilibrium Control During Locomotion
Authors: Deliagina T. G. 
Published: April 2021

ABSTRACT
Removal of a vestibular organ (unilateral labyrinthectomy, UL) in the lamprey (Lampetra fluviatilis) results in a loss of equilibrium, so that the animal rolls (rotates around its longitudinal axis) almost continuously when swimming. This paper describes (i) UL-evoked disturbances of the pattern of locomotory movements responsible for rolling, (ii) recovery of equilibrium control after UL (vestibular compensation), and (iii) the role of vision in the recovery of equilibrium control.
It was found that rolling is caused by an asymmetry in the undulatory locomotory movements, with larger deviations of the head towards the side with an intact labyrinth. The rolling appeared to be synchronized with the undulatory locomotory rhythm: during one complete roll turn (360 °), two cycles of locomotion were performed. A characteristic feature of the UL-induced motor deficit in the lamprey is the alternation of episodes of impaired swimming (with a distortion of the body shape and of the locomotor pattern and with a loss of equilibrium) with episodes of normal swimming (without any marked distortion of the locomotor pattern or loss of equilibrium). In the course of recovery after UL, the duration and frequency of the appearance of episodes of normal swimming increased, whereas episodes of impaired swimming became less frequent and shorter.
The recovery of equilibrium control and the role of vision in recovery were investigated in lampreys with different combinations of lesions to the vestibular and visual sensory organs. In group 1 (UL only) animals, the time required for 80 % recovery was, on average, 33 days. In group 2 (UL and removal of both eyes) and in group 3 (UL and removal of the contralateral eye) animals, vestibular compensation was considerably retarded, and normal functioning of the roll control system was not regained even 3 months after UL. In contrast, in group 4 (UL and removal of the ipsilateral eye) animals, no impairment of the equilibrium control was observed, and the animals swam without rolling immediately after surgery. These findings indicate (i) that the visual system is important for the process of vestibular compensation, and (ii) that the deficiency in equilibrium control caused by UL can be abolished by means of unilateral (contralateral to UL) visual input.
The hypothesis is advanced that the main UL-evoked motor deficit in the lamprey (loss of equilibrium) is primarily caused not by a persistent static distortion of the body shape, but by a loss of function of the roll control system responsible for stabilization of the dorsal-side-up orientation during swimming. A conceptual model of the roll control system of the lamprey, formulated in our previous studies, is used here to present arguments in favour of this hypothesis.