bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acoustic Orientation in the Cricket Teleogryllus Oceanicus (Le Guillou)
Authors: Bailey Winston J. , Thomson Peter 
Published: April 2021

ABSTRACT
New information is presented on acoustic orientation in crickets following a comparison between a species with a discontinuous song pattern, Scap-sepidus maginatus (Murphey & Zaretsky, 1972) and one with a continuous song pattern, Teleogryllus oceanicus. The females acuity for side discrimination is ±10° from the body axis whereas the total phonokinetic response shows a greater degree of error. Females can scan their turn angle to target angles beneath 6o°. Error is expressed in terms of information loss through the total behavioural sequence. The cricket does not orient while moving, requires no fixed leg position during the stop for effective orientation and can establish source direction on the basis of at least two syllables. Evidence of differential anterior and posterior tympanic membrane function is suggested.
Mechanisms for Directional Hearing in the Sea Catfish (Arius Felis)
Authors: Tavolga William N. 
Published: April 2021

ABSTRACT
The marine catfish (Arius felis) uses directional hearing for the acoustical detection of obstacles, and is primarily dependent on the vector components of near-field acoustics. Directional sound, detected as lateral line action potentials, produces the strongest response on the side toward the stimulus. Responses are maximal in the 50–150 Hz range. The swim bladder is asymmetrical as a sound generator (7 dB front-to-back ratio). As a sound receiver, the swim bladder is even more directional (24 dB front-to-back ratio at 100 Hz). It is concluded that directional response to sound in fishes can involve the interaction of at least two mechanisms, in this case the lateral line and the swim bladder.
Miniature Potentials, Light Adaptation and Afterpotentials in Locust Retinula Cells
Authors: Tsukahara Y. , Horridge G. A. 
Published: April 2021

ABSTRACT
In dark-adapted retinula cells of the locust, the miniature potentials or bumps have amplitudes of 3–7 mV when recorded in the dark-adapted state with bevelled electrodes at very low light levels. For a sample of N × 378 they had a mean amplitude of 4·55 mV and s.d. 1·59 mV. These are called dark-adapted bumps, and their distribution of amplitudes is presumably a component of the noise of the visual signal in addition to the irregularity of occurrence of bumps.
The afterpotential which follows an intense flash is caused by the summation of bumps which become individually visible as they decline in frequency over a period of many minutes after the stimulus. When recorded over a period from 17 to 23 min after the stimulus, the amplitude of these light-induced dark bumps in a sample of N = 231 had a mean of 2·89 mV and s.d. of 0·92 mV. They also have a shorter duration than dark-adapted bumps.
Light-adapted bumps, which are defined as bumps which arise when light of low intensity falls on light-adapted cells, are statistically indistinguishable in amplitude or duration from light-induced dark bumps. The reduction in size, as compared to dark-adapted bumps, cannot be attributed to a change in membrane potential or to an increase in membrane conductance, which actually decreases during the period of decline of the after-depolarization. Therefore in the light-adapted state, each bump is caused by the opening of fewer sodium channels, or of less effective sodium channels than in the dark-adapted state.
A Respiratory Rhythm in Sea Anemones
Authors: Jones W. C. , Pickthall Veronica J. , Nesbitt S. P. 
Published: April 2021

ABSTRACT
Continuous recording of the O2 content of sea water containing an Actinia equina or a Metridium senile has revealed the occurrence of periodic deflexions on most of the records obtained. The deflexions are probably caused by the release of coelenteric fluid via the mouth. The average period of the rhythm varied from 24 to 43 min (14−15 °C). The period increased in darkness, but was unaffected by feeding, brief mechanical or electrical stimulation, longitudinal bisection of the column and excess KCl or MgCl2; 1·6 mm-KCN abolished the rhythm. The O2 depletion rate did not increase when the anemone contracted in response to stimulation, but it did after feeding, exposure to darkness, or the application of MgCl2. It decreased in the presence of excess KCl. These changes may result from alterations in shape of the anemone. The mechanism for the release of coelenteric fluid has yet to be elucidated. Calculations indicate that from to of the total O2 requirement may enter the tissues from the coelenteron, the remainder being taken up via the ectoderm.
The Effect of Progressive Hypoxia on Respiration in the Toad Bufo Marinus
Authors: Boutilier Robert G. , Toews Daniel P. 
Published: April 2021

ABSTRACT
As Bufo marinus became progressively hypoxic over a period of 90 min, there was a rise in arterial pH, presumably brought about by hyperventilation. The alkalosis gradually disappeared when oxygen levels became very low. It is suggested that this is the result of a respiratory or a metabolic pH adjustment, or both. Hypoxic animals developed a characteristic breathing pattern in which discrete periods of lung ventilations alternated with buccal oscillations or respiratory pauses. A pronounced bradycardia was associated with the concomitant decline of inspired and arterial . Although respiratory rates were greater than normal resting values in the initial stages of post-hypoxia, the pre-exposure breathing pattern was quickly restored. Following recovery from bradycardia (60 min), the breathing rates, arterial blood gases and pHa returned to normal within 30 min.
AN ANALYSIS OF CHANGES IN BLOOD pH FOLLOWING EXHAUSTING ACTIVITY IN THE STARRY FLOUNDER, PLATICHTHYS STELLATUS
Authors: Wood Chris M. , Mcmahon B. R. , Mcdonald D. G. 
Published: April 2021

ABSTRACT
Exhausting activity results in a marked and immediate drop in blood pH which gradually returns to normal over the following 6 h. The acidosis is caused largely by elevated levels, which vary inversely with pH. Blood lactate concentration increases slowly, reaching a maximum at 2−4 h post-exercise, and contributes significantly to the acidosis only late in the recovery period. The slow time course of lactic acid release into the blood permits temporal separation of the peak metabolic acidosis from the peak respiratory acidosis. Evidence is presented that a metabolic acid other than lactic also makes a modest contribution to the pH depression during the recovery period.
Further Studies On the Peripheral Auditory System of ‘CF-FM’ Bats Specialized for Fine Frequency Analysis of Doppler-Shifted Echoes
Authors: Suga Nobuo , Jen Philip H.-S. 
Published: April 2021

ABSTRACT
In the mustache bat (Pteronotus parnellii rubiginosus), the cochlear microphonie (CM) recorded from the round window is sharply tuned at 61 kHz and shows a prominent transient response to a tone burst at about 61 kHz (i.e. its amplitude increases exponentially at the onset of the stimulus and decreases at its cessation). In terms of the time constant (1·1± 0·3 ms) and the resonance frequency (61·1±0·43 kHz) of this transient response, the Q of this system, assumed to correspond to a second-order filter, is 204 + 57. Peripheral neurones sensitive to 61 kHz have a very sharp excitatory area (or tuning curve). The Q of a tuning curve markedly increases with the rise in best frequency up to 61 kHz and decreases beyond 61 kHz. The Q value of a single neurone with best frequencies between 60·76 and 61·75 kHz is 210±189. If the assumption that the CM is directly related to the mechanical motion of the basilar membrane is correct, the very sharp tuning curves of single neurones at about 61 kHz could be simply due to the mechanical timing of the basilar membrane. Since this animal predominantly uses a 61 kHz sound for echolocation and peripheral auditory neurones show a low threshold and extremely sharp tuning at about 61 kHz, its peripheral auditory system is specialized for the reception and fine-frequency analysis of the principle component of orientation sounds and echoes. Sharply tuned neurones can code a frequency modulation as small as 0·01%, so that the wing beat of an insect would be easily coded by them. Unlike the CM, N1 is tuned at 64 kHz. This difference in best frequency is simply due to the properties of a sharply tuned resonator and N1, and not due to a mechanism comparable to lateral inhibition.
The Effect of Sectioning Cranial Nerves V, VII, IX and X On the Cardiac Response of the Dogfish Scyliorhinus Canicula to Environmental Hypoxia
Authors: Butler P. J. , Taylor E. W. , Short S. 
Published: April 2021

ABSTRACT
Exposure of the dogfish to rapidly induced hypoxia caused an initial, large reduction in heart rate to 32 % of its initial normoxic value. When of inspired water reached its lowest level, heart rate increased to 65 % of its normoxic value and this rate was maintained until was returned to normal. Bilateral section of the branchial and pharyngeal branches of either cranial nerve IX or cranial nerve X had no significant effect on the cardiac response to rapidly induced hypoxia. Bilateral section of the pharyngeal and branchial branches of both of these cranial nerves abolished the initial large reduction in heart rate in response to rapidly induced hypoxia; heart rate fell steadily to 40 % of its initial normoxic value after 3 min. Bilateral section of cranial nerves V and VII had a similar effect, with heart rate reaching 62 % of its normoxic value, 3 min after exposure to rapidly induced hypoxia. When the four cranial nerves were bilaterally sectioned together, there was no significant change in heart rate after 3 min exposure to rapidly induced hypoxia. It is concluded that the oxygen receptors responsible for the brady-cardia elicited in dogfish by environmental hypoxia are innervated by cranial nerves, V, VII, IX and X and that if receptors in the C.N.s. are involved in the response, their role is minimal.
A Note on the Effects of Different Doses of Thyroid on The Fowl
Authors: Hutt F. B. 
Published: April 2021

ABSTRACT
Reports of the effects of thyroid feeding on fowls published to date by various investigators show some lack of uniformity. Giacomini (1924) and B. Zavadovsky (1925) have noted depigmentation of plumage when fresh thyroid gland was given orally in doses which, though not stated exactly, were relatively large. The latter writer also obtained the same result with dried preparations.
Nitrogen-Excretion in Selachian Ontogeny
Authors: Needham Joseph , Needham Dorothy Moyle 
Published: April 2021

ABSTRACT
The investigations to be described in this paper were originally undertaken in order to throw light on the utilisation of protein as a source of energy by the developing selachian embryo. It has been shown that in the case of the chick (Needham (24), Fiske and Boyden (14)) and of the frog (Bialascewicz and Mincovna (4)) there exists a peak in the intensity of protein breakdown during embryonic life, on each side of which the catabolism of these substances is much diminished. In the case of the mammal (cow and sheep, Lindsay (23) and others) the descending limb of the curve has alone been observed. Our intention was to extend these investigations to a selachian egg, and we obtained several interesting results, although special difficulties were encountered, e.g. (a) the lack of any good series of weighings of selachian embryos, and (b) the remarkably high concentration of urea in elasmobranch tissues, which makes it difficult to regard it wholly as a waste-product.
Temperature and Heart Rate in Chick Embryos
Authors: Parpart E. R. , Glaser Otto 
Published: April 2021

ABSTRACT
In accordance with expectation, the embryonic chick heart exposes recurrently temperature characteristics of the orders 8,200, 14,200, 16,400, 18,300, 20,500 and 25,200. These are found in both myogenic and neurogenic hearts but not with the same frequencies. These two periods of development also differ in the localisation of critical points. So far μ. = 8,200, 14,200 and 18,300 have been exposed in embryos only by Fundulus’, the remaining three orders however are recurrent also in the embryogeny of Limulus. Two orders not included in this list (5000 and 11,000) are rare, yet, even so, not restricted to any one of the three forms. These facts, together with their implications, suggest for heart rhythm in Limulus, Fundulus and the Chick, an underlying physical-chemical mechanism in structure identical for all three types of heart at all stages of development, and differing in neurogenic stages only by a revision of the myogenic time relations.
On Genital Maturity in an Immature Soma
Authors: Mirskaya L. , Crew F. A. E. 
Published: April 2021

ABSTRACT
In the urine from a pregnant woman there are to be found certain physiologically active factors, regarded by Zondek and Aschheim as an elaborated product of the anterior lobe of the pituitary, profoundly influencing the activity of the ovary of rat and mouse, and thus indirectly invoking oestrus. The effect of the injection of urine from a pregnant woman upon the immature female mouse is a maturation of the genital system.
On Phosphorus Metabolism in Embryonic Life
Authors: Needham Joseph , Needham Dorothy Moyle 
Published: April 2021

ABSTRACT
An investigation was made of the phosphorus metabolism of several marine invertebrate eggs (two echinoderms, one gephyrean annelid, and two Crustacea). The distribution of phosphorus-containing compounds was measured before and after development had taken, place. Data are given for the total and lipoid phosphorus, the total water-soluble and stable organic water-soluble phosphorus, the inorganic ortho-and pyro-phosphate, the phosphoprotein and the nucleoprotein. During the development of the sand-crab (Emerita analoga) water is absorbed from the environment, as in the well-known cases of the frog, the trout, and various cladocerans. The egg shell of the brine-shrimp (Artemia salina) contain both calcium and haematin, offering thus a parallel with the shell of avian eggs. During the development of the sanddollar egg (Dendraster excentricus) there is an increase in total phosphorus per unit weight of dry solid. It is pointed out that this absorption of an element from the sea water by the embryo must be taken into account in considering the penetration of marine organisms into fresh water, if, as seems probable, the phosphorus concentration in an aqueous environment may act as a limiting factor. The spicules of the sanddollar pluteus probably contain inorganic phosphate, in quantity roughly corresponding to the amount taken in by the developing egg from the sea water. In all cases so far studied the extent to which lipoid phosphorus is transformed into other forms of phosphorus during embryonic life is proportional to the amount of lipoid phosphorus present at the time of fertilisation. Included in the large stores found in certain eggs there is a fundamental quota which no egg can do without, though this may be, reckoned in absolute values, very small. A computation shows that the contribution of one echinoderm spermatozoon to one egg is of the order of a ten-thousandth part of the phosphorus which is there already. The analyses reported in this paper indicate that, in spite of the large increase of visible nuclear matter during echinoderm development, there is no corresponding synthesis of nuclein. The formation of the chromatin of the nuclei must therefore consist in an organisation of preformed nucleic acids into structural arrangement and not in a manufacture of these compounds by chemical means from other raw materials. Nuclein synthesis, however, certainly occurs in some eggs, and study of the relevant investigations of other workers leads to the conclusion that it is associated with uricotelic metabolism, terrestrial development, and the properties of cleidoic embryos. Wherever the purine ring is synthesised by embryonic cells for nitrogen excretion, there a notable synthesis of the purine ring for cell-nuclei is also found : whatever this is not so, there the eggs are provided by the parent organism with sufficient nuclein for the needs of the embryos.
The Effect of Carbon Dioxide On the Occurrence of Non-Disjunction In Drosophila
Authors: Mottram J. C. 
Published: April 2021

ABSTRACT
The fact that X-rays and radium produce permanent changes in the mechanism of heredity (originally observed by Mavor (1) for non-disjunction and by Muller(2) for mutations) has been widely confirmed by many workers(3). Apart from these radiations no other agent has been found to effect heredity similarly, except for the claim made by Harrison and Garrett (4) that feeding the larval of several species of Lepidoptera on metallic salts results in melanotic mutations.
Changes in Calcium Transport Across Calliphora Salivary Glands Induced by 5-Hydroxytryptamine and Cyclic Nucleotides
Authors: Berridge Michael J. , Lipke Herbert 
Published: April 2021

ABSTRACT
The efflux of 45Ca from prelabelled salivary glands was studied under a variety of conditions. 5-Hydroxytryptamine (5-HT) or cyclic AMP caused a large release of label most of which entered the saliva. The ionophore A23187 caused a similar release of calcium but EGTA had no effect.
The presence of an active calcium pump on the lumenal surface was investigated further by studying calcium transport across the gland. This transport of calcium, which provides a measure of calcium entry into the cell, was very sensitive to 5-HT concentration but little affected by cyclic AMP. The small cyclic AMP-dependent transport was depressed by 8-bromo cyclic GMP with a parallel fall in the rate of fluid secretion.
These studies provide more direct evidence that 5-HT acts to stimulate the entry of external calcium in addition to mobilizing internal calcium.
Respiratory Gas Exchange in the Resting Starry Flounder, Platichthys Stellatus: A Comparison With Other Teleosts
Authors: Wood Chris M. , McMahon B. R. , McDonald D. G. 
Published: April 2021

ABSTRACT
A wide range of respiratory, ventilatory, and cardiovascular parameters have been recorded under completely resting conditions in the starry flounder (Platichthys stellatus), a generally inactive benthic teleost. The results differ in a number of important respects from those of a previous study on the same species. The present data have also been compared with those reported for the active pelagic rainbow trout (Salmo gairdneri) and for other teleost species. Of particular note in the flounder, relative to the trout, are low arterial and venous ’s, a low arterial-venous O2 content difference, a low transfer factor and nigh diffusion gradient for O2 across the gills, a high in vivo blood O2 affinity, a high cardiac output and stroke volume accompanied by a low peripheral vascular resistance, a low ventilation volume, a low ventilation-perfusion ratio, and a low capacity-rate ratio for O2 exchange at the gills. Parameters of CO2 transport and acidbase regulation appear conventional, though blood CO2 contents and lactate concentrations are low. The respiratory strategies of inactive versus active, and benthic versus pelagic teleosts are discussed.
The Feeding Response ofRhodnius Prolixusto Blood Fractions, and the Role of Atp
Authors: Smith J. J. B. 
Published: April 2021

ABSTRACTSecond-instar larvae of Rhodnius prolixus will gorge on washed human erythrocytes suspended in Ringer, but not on plasma, either with or without platelets. The ED 50 of erythrocytes is 4·5 vol of packed cells per 1000 vol of Ringer. Erythrocyte ‘ghosts’ are non-stimulatory, whereas the haemolysate induces gorging. Phagostimulation by ‘ghosts’ is restored by resealing them in 1 mm adenosine triphosphate. Evidence is presented that Rhodnius responds to blood via a release of ATP from a few erythrocytes close to the epipharyngeal sense organs.
Electrogenic Na+ Transport in A Crustacean Coxal Receptor
Authors: Mirolli Maurizio 
Published: April 2021

ABSTRACT
The response of the coxal receptors of the crab Scylla serrata to step stretches consisted of a partial action potential, Va, followed by a steady-state depolarization, Vs. The input resistance of the fibre was reduced during Vs. In the absence of stimulation, the dendrites of the receptors depolarized when external Na+ was substituted with choline or Li+, and when the external K+ concentration was increased or decreased. The dendrites also depolarized when ouabain was added to the saline. The amplitude of both Va and Vs was dependent on external Na+. In cells which were depolarized by ouabain, the amplitude of Vs increased when the K+ concentration of the saline was reduced. V s , was followed by a small, but long-lasting, after-potential which was depolarizing when the membrane potential was between −70 and −60 mV. In cells depolarized by ouabain or by low K+ saline, the after-potential became hyperpolarizing. When trains of brief stretches (each 5 ms in duration) were used as stimuli, the cells responded with trains of Va responses. During this tetanic stimulation the cells hyperpolarized; cessation of the stimulus train was followed by a long-lasting hyperpolarization (PTH). PTH was abolished in Li+ saline, in low K+ saline, and in the presence of ouabain. In control or in low K+ saline, PTH was not accompanied by a decrease in the input resistance of the fibres. It is concluded that an electrogenic Na+ pump (or equivalent process) contributes a substantial fraction of the membrane potential of the unstimulated coxal receptors. Pump activity could be increased by Na+-loading the distal part of the cells with trains of Va responses. By contrast, during the steady-state response to stretch, the pump was not activated.
Neurobiology of the Gorgonian Coelenterates, Muricea Californica and Lophogorgia Chilensis
Authors: Satterlie Richard A. , Case James F. 
Published: April 2021

ABSTRACT
Electrical or mechanical stimulation of Muricea californica or Lopho- gorgia chilensis colonies resulted in withdrawal of polyps in the immediate vicinity of the stimulation point. Additional stimulation did not result in further spread of polyp retraction. Electrical activity was recorded from a colonial conduction system not restricted to the area of polyp withdrawal. Conduction velocity in this conduction system decreased with increasing stimulus number and distance from the stimulation point. Polyp withdrawal in Muricea occurred concomitantly with a burst of facilitating electrical impulses. The withdrawal burst was always preceded by impulses of the colonial conduction system. The pattern of colonial behaviour in gorgonians depends upon the conduction properties of the colonial conduction system, the conduction system(s) of each individual polyp, and the pathways connecting the two. Polyp tentacles bend to the oral disk when presented with liver extract. A burst of electrical impulses was recorded from Muricea polyps during chemical stimulation. These bursts exhibited apparent adaptation and presumably represent muscle potentials resulting from chemoreceptor activation.