bluuebunny/crossref_metadata_2025_split huggingface dataset:
The metabolism of acetylcholine in the intact central nervous system of an insect (Periplaneta Americana L.)
Authors: Treherne J. E. , Smith D. S. 
Published: April 2021

ABSTRACT
A very rapid metabolism of 3H-labelled acetylcholine has been demonstrated in the intact abdominal nerve cord. It has been shown that the cholinesterase system is effective in drastically reducing the concentration of acetylcholine in the extracellular fluid of the terminal abdominal ganglion with bathing solutions of up to 10−2 M acetylcholine. Evidence has been obtained which indicates that an appreciable hydrolysis of acetylcholine occurs at the periphery of the nerve cord. This effect is correlated with the electronmicroscopic demonstration of regions of eserine-sensitive cholinesterase located on glial membranes in the periphery of ganglia and connectives. It is suggested that some hydrolysis of extraneous acetylcholine may occur in the fibrous layer of the nerve sheath as a result of an accumulation of diffusible acetylcholinesterase in this region. The results are discussed in relation to the possible involvement of the conven­tional cholinergic system in synaptic transmission in the central nervous system of this insect.
The Physiology of Excretion in the Cotton Stainer, Dysdercus Fasciatus Signoret: III. Nitrogen Excretion and Excretory Metabolism
Authors: Berridge M. J. 
Published: April 2021

ABSTRACT
The nitrogenous components of the urine are: allantoin, urea, amino acids, kynurenine, and a mucopolysaccharide. The main nitrogenous excretory product is not uric acid, as in other terrestrial insects, but allantoin. The excretion of total nitrogen, allantoin nitrogen, urea nitrogen and amino acid nitrogen have been followed throughout the excretory phase. The concentration of allantoin in the urine is always less than that in the haemolymph, and is a result of the low permeability of the Malpighian tubules to this substance. When isolated Malpighian tubules were used the average U/P ratio was 0·45. Waste nitrogen is also excreted by storage excretion of uric acid in the epidermal cells ; the rate of deposition is most rapid during the excretory phase. Low allantoin excretion and a low rate of uric acid deposition in the epidermis during the post-excretory phase suggest that uric acid synthesis is markedly reduced during this phase. Uricase is concentrated in the Malpighian tubules, where it accounts not only for the absence of uric acid in the urine but also for the high concentration of allantoin in the haemolymph. Calculations based on allantoin excretion show that only 28% of the primary tubule fluid is reabsorbed from the rectum. Since allantoin is more soluble than uric acid, it is better suited as a nitrogenous waste substance in such an excretory system, which recycles little water. The method of excreting waste nitrogen is compared with that of other insects.
Split-Brain Preparations and Touch Learning in the Octopus
Authors: Wells M. J. , Young J. Z. 
Published: April 2021

ABSTRACT
A vertical longitudinal cut through the supraoesophageal part of the brain does not prevent discrimination between rough and smooth cylinders. It does, however, prevent correct response by the opposite side after training on one side of the animal. Octopuses with intact supraoesophageal lobes, trained on one side, discriminate when tested with the same objects on the other side; split-brain animals do not. In this situation, the performance of one side of the octopus can be used as a control for the effect of a brain lesion in the other. Removal of large parts from the supraoesophageal brain does not prevent touch-learning. Discrimination continues until the lesion includes the whole of the subfrontal lobe on the side concerned. Some of the small amacrine cells of the subfrontal/posterior buccal region must remain if learning is to occur. There are normally about 2·5 × 106 of these in each side of the subfrontal lobe ; animals continued to discriminate between rough and smooth cylinders with as few as 10,000 of these cells remaining, but failed when none were left. Octopuses with the brain intact or with the vertical lobes removed do not show marked rough/smooth preferences. In animals with large lesions to the inferior frontal system, however, there is a preference for rough, so that rough +/smooth — is an easier discrimination than vice versa.
The Nervous Pathways for Poisoning, Eating and Learning in Octopus
Authors: Young J. Z. 
Published: April 2021

ABSTRACT
Octopuses after removal of the lip kill and eat crabs apparently normally. They learn to attack a strange figure moving in the visual field. The pair of nerves that originates from cells at the back of the superior buccal lobe is shown to be responsible for the discharge of secretion from the posterior salivary glands. If this pair of nerves is interrupted the octopus does not poison a crab after catching it. It still eats, however, and learns to attack a strange figure. If both interbuccal connectives have been severed the octopus does not remove the flesh properly from crabs. It does not learn to attack a strange figure. Any operation on the central nervous system that interrupts the pathway from the interbuccal connectives to the lateral superior frontal and optic lobes prevents learning to attack a figure that has been seen. If such cuts pass through the middle of the superior buccal lobe the animal does not poison crabs or completely remove the flesh from their exoskeletons. If the cut is through the back of the superior buccal lobe the octopus does not poison crabs but may tear them open and then clean and eat them. With cuts still farther back the animal poisons, cleans and eats crabs, but still does not learn to attack.
Sensory Modalities and Receptive Fields in the Abdominal Nervous System of the Hermit Crab, Pagurus Granosimanus (Stimpson)
Authors: Chapple William D. 
Published: April 2021

ABSTRACT
The way in which adaptation to a particular environment takes place within the central nervous system of vertebrates has been the subject of research for over a hundred years. The development of specific reflexes from generalized action patterns, the precedence of changes in motor systems over changes in sensory systems, and the metamorphosis of sensory relay nuclei and centres of primary integration into areas subserving more complex functions (Herrick, 1948) are some of the ways in which adaptation is reported to have occurred. Furthermore, Bishop (1961) has suggested that the emphasis upon functional criteria alone as a key to the function of a specific nervous system neglects those features of the system which owe their presence to its evolution from a nervous system adapted to perform other tasks. During their evolution, the newer centres of integration which have developed as a result of new requirements have not abolished the older centres, which may retain many of their old properties. It is clearly of interest to determine whether nervous systems of groups other than vertebrates exhibit the same regularities in their adaptation, and if possible to examine the alterations in response to different selective forces at the single-unit level.
Surface Characters of Dividing Cells
Authors: Ishizaka Shozo 
Published: April 2021

ABSTRACT
Surface movement of the dividing spermatocyte of the grasshopper, Acrida lata, was followed by a marking method. Throughout the division process of the spermatocytes, incipient daughter cells maintain spherical contours. By direct observation of markers and calculation using the condition given in item 2, the following points are established. (a) As in the sea-urchin egg, there are a pair of circular zones on a grasshopper spermatocyte surface which retain their respective radii unchanged while the cell undergoes a division.(b) In the grasshopper spermatocyte, unlike the sea-urchin egg, the surfaces of these circular zones do change their positions and move towards the poles during division.(c) As a spherical cell goes through a constricted form to become two daughter cells, not only is the radius of curvature of the surface everywhere uniform (item 2), but both axial length and surface area increase uniformly everywhere except in the region of the furrow. From the findings of item 3 it is inferred that the prevailing surface stress is uniform and isotropic, like surface tension, and that the force causing division must be derived from some other parts of the cell such as the furrow cortex or the endoplasm. Basically, the nature of the surface of sea-urchin eggs is similar to that of the spermatocyte. That the circular zones of the former are stationary while those of the latter move steadily during cleavage is tentatively explained in terms of the speed of advance of the furrow in relation to the relaxation time of the cortex.
Adaptation and Other Phenomena in the Optokinetic Response of the Crab, Carcinus
Authors: Horridge G. A. 
Published: April 2021

ABSTRACT
During the course of the experiments which have contributed to the previous papers there appeared a number of new observations which did not fit readily into those topics. Although each is a qualitative new finding which seems at first sight to refer to only one aspect of the optokinetic response, taken together they shed further light on the type of system we are dealing with. All of these new observations could be quantified in detail, but it appears that a highly accurate set of measurements which are intended to measure the parameters of one simple system are out of place until a wide variety of qualitative experiments, with suitable controls, have narrowed down the choice of alternative models.
Some Factors Affecting Flight Activity in Individual Milkweed Bugs (Oncopeltus)
Authors: Dingle Hugh 
Published: April 2021

ABSTRACT
Individual adults of Oncopeltus were tested repeatedly at 2- or 3-day intervals, using tethered flight, to determine the amount of flight activity as measured by flight duration. The peak period of activity occurred 8 days after the final moult with later flights scattered and showing no concentration at a particular age. Deposition of cuticular growth rings ceased at about 7 days ; the peak activity was thus post-teneral and probably represents migration. Only 23·8 % of bugs tested showed flights of over 30 min. Those bugs which flew for long periods at 8 days were more likely to show long flights at a later age than were bugs which did not fly at day 8. There thus seems to be a behavioural polymorphism with distinct ‘flyers’ and ‘non-flyers’. More females, 30·7%, than males, 18·1 %, exhibited flights of over 30 minutes. Males which did have such long flights were, however, more likely than females to have them repeatedly. In both sexes virgins seemed to be more active in respect of long flights than bugs allowed continuous contact with the opposite sex. Calculations based on estimates of flight speed and total duration of flight indicate that an individual migrant Oncopeltus is capable of covering a considerable distance, 100 kilometres or more, during its lifetime.
The Effect of Ouabain on the Efflux of Sodium Ions in the Nerve Cords of Two Insect Species (Periplaneta Americana and Carausius Morosus)
Authors: Treherne J. E. 
Published: April 2021

ABSTRACT
The intracellular efflux of 22Na from the nerve cord is reduced by the presence of ouabain in the bathing medium. With Periplaneta 10−6M ouabain caused a reduction in the rate constant for sodium efflux from 3·94 × 10−3 sec.−1 to 1·80 × 10−3 sec.−1 and in Carausius from 1·14 × 10−3 sec.−1 to 6·18 × 10−1 sec.−1. Uncoupling of the energy supply to the sodium pump, by the addition of cyanide, did not further reduce the sodium efflux from ouabain-treated axons, suggesting that the greater part of the active extrusion of this cation is effected by a single ouabain-sensitive carrier mechanism. The relative insensitivity to ouabain of the insect axons, as compared with squid giant axons, is shown to result from the presence of a rather leaky axon membrane in which the carrier-mediated component forms a much smaller part of the total flux. The concentration gradient of sodium across the insect axon membrane is related to the combined effects of the activity of the sodium pump and the passive permeability of the membrane.
Effects of Increased Viscosity on the Movements of Some Invertebrate Spermatozoa*
Authors: Brokaw C. J. 
Published: April 2021

ABSTRACT
Two distinctly different patterns of sperm movement in response to increased viscosity have been found, which appear to be variations in the behaviour of a common mechanism for generating and controlling flagellar bending waves. One type of pattern is found with the normal movements of spermatozoa of Ciona and Lytechinus, and with glycerinated Lytechinus spermatozoa when their movements are reactivated at high (2 mM) ATP concentrations. The radius of curvature of the bends on the flagellum, and the viscous bending moment, remain relatively constant, while the propagation velocity, wave amplitude, and energy expenditure decrease with increasing viscosity. The second pattern of response is found with the normal movements of spermatozoa of Chaetopterus, with Lytechinus spermatozoa when the beat frequency is reduced by the presence of an inhibitor, thiourea, and with glycerinated Lytechinus spermatozoa when their movements are reactivated at low (0·2 mM) ATP concentrations. The decrease in propagation velocity with increasing viscosity is accompanied by substantial reductions in the radius of curvature, and the wave amplitude is not greatly decreased. This response involves an increase in viscous bending moment and energy expenditure as the rate of bending decreases, and may resemble the increased force and work outputs obtainable from muscle at reduced shortening velocities. This type of response is obtained under conditions where the initial beat frequency and energy expenditure are relatively low, and may not be possible when the initial level of energy expenditure is higher. Although each species shows a unique pattern of changes in frequency and wavelength with increasing viscosity, the relationship between bend propagation velocity and viscosity has nearly the same form in each case, indicating that the velocity of bend propagation is relatively independent of the magnitude of the bend. This result is consistent with at least one proposed mechanism for bend propagation. On the basis of this mechanism, the results suggest that the rate of bending is independent of the magnitude of the bend and inversely proportional to the square root of the viscosity. In some cases, the wavelength and other wave parameters are adjusted so that a constant proportionality between viscous and elastic bending moments will be maintained as the viscosity is increased. This proportionality will also be maintained during the passive propagation of bending waves along an inert flagellum, and for an active flagellum it implies that the wave parameters are adjusted so that energy stored in elastic bending of the flagellum could be efficiently used to effect unbending, without indicating how this adjustment is accomplished. Other cases, in which the proportionality between viscous and elastic bending moments is not maintained, may represent cases where the flagellum is not operating efficiently. Under certain conditions the normal nearly planar bending waves of Ciona spermatozoa are replaced by helical bending waves.
Circulation in A Giant Earthworm, Glossoscolex Giganteus
Authors: Johansen Kjell , Martin A. W. 
Published: April 2021

ABSTRACT
Oxyhaemoglobin dissociation curves have been obtained for Glossoscolex giganteus. The t50 value was 7 mm. Hg. at 20° C. and pH 7.58. There was no significant Bohr effect. Oxygen capacity averaged 14.0 vol. % for fifteen animals. The corresponding value for haemoglobin expressed as iron content was 30 mg. %. Blood was sampled anaerobically from the dorsal vessel on non-anaesthetized freely moving specimens and analysed for O2 and CO2 content. Blood-gas levels were studied in animals placed on moist surfaces or buried in shallow moist soil. The effects of drug injections and changes in the composition of the external gases were measured. Patterns of gas exchange and the role of haemoglobin in gas transport in the earthworm are discussed.
The Dimensions of Fish Gills in Relation to Their Function
Authors: Hughes G. M. 
Published: April 2021

ABSTRACTMeasurements have been made of the gill areas of fourteen species of British fish, all marine except for the tench and trout. In addition the gill area of the Antarctic icefish, Chaenocephalus (lacking haemoglobin) has been measured. The different parameters of the gill sieve have been considered quantitatively in relation to the size of the gill area, resistance to the passage of water, and the diffusion conditions at the gills. From calculations of the expected flow through a sieve of the measured dimensions it has been concluded that a sufficient volume would pass in the inter-lamellar spaces despite their fine dimensions. Differences in the nature of the sieve relative to the theoretical one and changes during the respiratory cycle account for the ventilation volumes measured being less than those calculated. The theoretical analysis of the operation of the gill sieve are discussed in relation to measurements of Gray (1954) and to the developmental studies of Price (1931). It is concluded that more active fish not only have larger gill areas but that the conditions for gaseous exchange are better than for more sluggish forms and that the area is increased in such a way as to keep the resistance to flow to a low value. This is mainly achieved by having an increased total filament length and a large number of secondary folds. More sluggish fish have more widely spaced and higher lamellae and their total filament length is reduced. The resistance to flow relative to the area is less in these forms than in the more active species. Consideration is given to the different pathways along which water can infiltrate past the respiratory epithelium and analogies are drawn with the alveolar air, and the physiological and anatomical dead-spaces of the mammalian lung.
The Metabolic Effects of the Corpus Allatum Hormone in the Male Desert Locust
Authors: Odhiambo Thomas R. 
Published: April 2021

ABSTRACTAn account is given of the normal pattern of total lipid content of male desert locusts from the time of adult emergence to the time the locusts are approaching senescence (18—25 days). Up to the seventh adult day, there is a rapid increase in the amount of body lipids ; thereafter, there is a progressive depletion of lipid reserves. Allatectomy of the locusts soon after adult emergence leads to considerable accumulation of lipids which becomes apparent when the locusts attain sexual maturity and persists thereafter. Gonadectomy or mere wounding has no such effects. Implantation of active corpora allata in previously allatectomized locusts reverses the tendency to lipid accumulation.
Asymmetry of the Motor System in the Hermit CrabPagurus GranosimanusStimpson
Authors: Chapple William D. 
Published: April 2021

ABSTRACTThe decalcification of the abdomen and the asymmetry of the central flexors is a ‘hydrostatic’ mechanism by which the abdomen is expanded to fit the shell tightly. The single pair of giant fibres is homologous to the medial giants of the crayfish except that no contralateral activation of the flexor muscles was observed. Two kinds of asymmetry in the motor system were observed; (a) loss of motor fibres in the first ganglionic roots of the right side; (5) greater frequency of ‘spontaneous activity’ in the slow flexor branch of the third roots on the left side. Sensory stimulation evoked different sets of fibres in these third root branches; one set fired spontaneously even after total ganglionic isolation, the other, when reflexly activated, reciprocally inhibited the first group. Antidromic and synaptic inputs failed to re-set the spontaneous activity; two kinds of reflex activation, phasic and tonic suggest two different sites for inputs, one to the motoneurons, the other to a pre-synaptic pacemaker. Alternations of the two reflex groups occurred in the totally isolated ganglion; addition of picrotoxin to the saline abolished reciprocal inhibition but variations in the frequency of spontaneous activity persisted. A possible mechanism for this system is proposed.
Changes of Internal Hydrostatic Pressure and Body Shape in Acanthocephalus Ranae
Authors: Hammond R. A. 
Published: April 2021

ABSTRACT
Two hydraulic systems are primarily concerned in the movements of Acanthocephalus ranae (Schrank, 1788; Lühe, 1911), that of the proboscis apparatus and that of the trunk (Hammond, 1966a). The muscles associated with each system operate about a fluid skeleton of constant volume. Muscular activity in either system, and therefore change of body shape, is accompanied by a change of hydrostatic pressure within the skeletal fluid.
The Balance Between Antagonistic Induction and Depression of Flight Activity in Aphis Fabae Scopoli
Authors: Kennedy J. S. 
Published: April 2021

ABSTRACT
A bout of settling activity on a leaf or other surface has both excitatory and inhibitory effects upon subsequent flight activity (antagonistic induction and depression of flight by settling); flight has similar after-effects upon settling; and the changing balance between these reciprocal after-effects determines the general course of behaviour. The strength and duration of settling responses made on landing by free-flying aphids were regulated by jolting them off the surface into flight again prematurely. This treatment diminished but did not otherwise appear to distort the after-effects of a landing on flight and was used to establish the following points. The balance between the excitatory and inhibitory after-effects of any one landing on flight depends (i) on the excitatory states of both flight and settling before the landing occurs, and (ii) on the strength of the settling stimuli received from the surface after landing. The after-effects of settling on flight are predominantly excitatory when flight is already strong relative to settling but predominantly inhibitory when flight is relatively weak; the after-effects of strong settling are consistently greater, both ways, than those of weak settling. Landings on different surfaces known to provide weak and strong settling stimuli still produce their typically different after-effects on flight when the settling responses actually performed on the two surfaces are kept equal. The after-effects of settling on flight evidently do not require any peripheral feed-back (although this can add to the after-effects), and result from central cross-inhibition of flight when settling is centrally excited by external stimuli.