bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tracheal Gases, Respiratory Gas Exchange, Body Temperature and Flight in Some Tropical Cicadas
Authors: Bartholomew George A. , Barnhart M. Christopher 
Published: April 2021

ABSTRACT
Fidicina mannifera Fab. (mass 3 g) can fly at a body temperature of 22 °C, but take-off is usually preceded by an endothermic warm-up that elevates Tth to 28 °C or higher. Warm-up is accompanied by slow, almost imperceptible, wing movements, gentle abdominal pumping and an increase in V·O2 to about 16 times the resting level. During wing-flapping in fixed flight, V·O2 increases explosively to about 70 times the resting level, and thoracic temperature rises to about 33 °C. Wing-beat frequency increases with Tth. Between 25 and 34 °C the mean wing-beat frequency is about 37 Hz. F. mannifera does not maintain free flight, or wing flapping in fixed flight, for more than about 100 s. Flight is supported aerobically, and we infer that exhaustion is related to depletion of substrate in the flight muscles.
The volume of the tracheal system of F. mannifera is about 45 % of total body volume. At rest, FO2 in the thoracic air sacs remains near 17 % and FCO2, near 3 %. During non-flapping warm-up, FO2 falls to as low as 1 % and FCO2 rises to as high as 21 %. Thus, gas exchange may limit the rate of warm-up. When wing-flapping commences, FO2 and FCO2 quickly return to near resting levels, presumably as a result of auto ventilation.
The interspecific regression of V·O2 on mass for three species of cicadas at 23-24°C has a slope of 0·89 and a 1-g intercept of 0·63 ml h−1.
A Movement Generated in the Peripheral Nervous System: Rhythmic Flexion by Autotomized Legs of the Stick Insect Cuniculina Impigra
Authors: Bässler U. 
Published: April 2021

ABSTRACT
Autotomized legs of the stick insect Cuniculina impigra bend rapidly and rhythmically at the femur-tibia joint. These flexions occur at a frequency of 1–6 Hz immediately after autotomy and decrease in frequency and amplitude with time. Each flexion is produced by a burst of 1–14 action potentials in a single motor axon of the flexor tibiae muscle (bursting axon). These rhythmic discharges are generated in a very restricted part of the crural nerve, which contains the bursting axon, close to the autotomy point and appear whenever the nerve is cut in the immediate vicinity of this generator region. Rhythmic flexion can also be elicited by electrical stimulation of the crural nerve.
The bursting axon is of small diameter. It innervates all or most of the flexor tibiae muscle in which it produces relatively large EPSPs. Each EPSP elicits one muscle twitch. These fuse into a brief tetanus, whose amplitude is proportional to the number of spikes in a burst. Each tetanus produces one flexion.
This behaviour does not occur in the autotomized legs of several related species.
KCl Transport Across an Insect Epithelium: Characterization of K-Stimulated Cl Absorption and Active K Transport
Authors: Hanrahan J. W. , Phillips J. E. 
Published: April 2021

ABSTRACT
The kinetics of 36C1 fluxes across cAMP-stimulated, short-circuited locust rectum were studied. Raising external K+ from 0 to 100 mM increased both Kt and Vmax for net Cl transport by four- to six-fold. Hill plots of indicated non-cooperative Cl interactions. The sequence for cation stimulation of was K &gt; Rb &gt; Cs &gt; Na &gt; NH4. Low levels of K were stimulatory only when added to the mucosal side. Cyclic AMP (cAMP) caused a small active absorption of K, although this was minor compared to the fourfold increase in transepithelial K diffusion (PK ). Neither cAMP stimulation of nor of PK was sensitive to Cl removal, suggesting that K-stimulated Cl absorption and K transport are not mediated by the same co-transport mechanism. Potassium is the counter-ion for electrogenic Cl transport because was less than 10% of the during cAMP exposure under Isc conditions, but equalled at open-circuit.
Electrolyte composition of parotid saliva from sodium-replete red kangaroos (Macropus rufus)
Authors: Beal A. M. 
Published: April 2021

ABSTRACT
Saliva was collected from the parotid salivary gland of anaesthetized sodium-replete red kangaroos (Macropus rufus) by catheterization of the parotid duct through its opening in the mouth. Salivary secretion was stimulated by ipsilateral intracarotid infusion of acetylcholine at varying rates to produce salivary flow rates ranging from 0·056 ± 0·0042 (S.E. of mean) to 4·509 ± 0·1136 ml min−1. The concentrations of sodium (142·2± 1·93 to 157·0± l·17mmoll−1), calcium (40·1±7·08 to 72·8± 80μmoll−1) and bicarbonate (68·6±3·48 to 143·3 ± 0·67 mmol l−1) and the osmolality (270·1 ± 2·98 to 291·7 ± 2·10 mosmol kg−1) were positively correlated with salivary flow rate, whereas the concentrations of potassium (11·4±0·57 to 6·92± 0·19 mmol l−1), magnesium (206·0±34·1 to 9·3 ± 0·78μmol l−1), hydrogen ion (17·0± 1·89 to 6·82± 0·49 nmol l−1), chloride (30·7 ± 2·41 to 4·11± 0·23 mmol l−1) and phosphate (47·61± 2·65 to 14·9 ± 0·81 mmol l−1) were negatively correlated with flow rate. The relationships between flow rate and concentration were curvilinear for all the inorganic solutes. The rates of secretion for each ion and for total solute were positively correlated with salivary flow rate. These regressions for sodium, potassium, calcium, hydrogen ion, bicarbonate and osmolality were always linear, with highly significant correlation coefficients and variance ratios, which indicated that the changes in concentration of these ions were related solely to flow rate and were not due to any other factor modifying glandular function. Spontaneous secretion was’not observed during anaesthesia.
Stimulation of chemosensory pathways and intracellular alkalinization mimic cAMP activation of endogenous bursting in feeding command neurones
Authors: Gillette ML 
Published: April 2021

ABSTRACT
Cyclic nucleotides modulate the activity of diverse types of excitable cells (Twarog & Muneoka, 1973; Berridge, 1975; Triestman & Levitan, 1976; Greengard, 1980; Bernier, Castellucci, Kandel & Schwartz, 1982; Gillette, Gillette & Davis, 1982b; Evans, 1984). In the carnivorous gastropod Pleurobranchaea, it would appear that cAMP modulation of a single pair of neurones effects the expression of a complex coordinated rhythmic behaviour. These neurones, the ventral white cells (VWCs), command vigorous motor output from the neuronal feeding oscillator through an intrinsic capacity to generate minutes-long high intensity bursts of action potentials (Gillette, Gillette & Davis, 1980). This high frequency firing causes the action potentials to increase in duration (broaden). The increase in action potential duration is a specific antecedent to enhanced motor output through a Ca2+-dependent mechanism (Gillette, Gillette & Davis, 1982a). Elevated intraneuronal cAMP is a specific activator of prolonged VWC bursting in both the isolated nervous system and the isolated VWC soma (Gillette et al. 1982b). The relationship between this endogenous effector (cAMP) and extrinsic activators of the motor programme has not been established.
Lithium attenuates the active transport of calcium in the larva of Aëdes aegypti
Authors: Barkai AI , Williams RW 
Published: April 2021

ABSTRACT
Larvae of the freshwater mosquito Aëdes aegypti (L.) are able to maintain their principal electrolytes against a steep concentration gradient between the haemolymph and the external medium. The concentration of monovalent ions such as Na+, K+ and Cl- is kept far above that in the external medium by processes of active transport which are located in the anal papillae, the rectum and the Malpighian tubules (Koch, 1938; Ramsay, 1953; Treherne, 1954; Stobbart, 1959, 1960, 1965, 1967). Ithasbeen demonstrated that over 90 % of the exchange of monovalent ions occurs through the anal papillae (Treherne, 1954), but these organs are not permeable to bivalent ions (Wigglesworth, 1933). The processes which regulate the exchange of bivalent ions between the larva and the external medium have not yet been elucidated. Recently, we have demonstrated that larvae of Aëdes aegypti maintain a saturable transport system for the uptake of calcium ions from dilute calcium solutions (Barkai & Williams, 1983). This system obeyed Michaelis-Menten kinetics and its activity was susceptible to ruthenium-red which selectively inhibits Ca2+-activated ATPase (Watson, Vincenzi & Davis, 1971).
Effects of in vivo and in vitro changes in on the deformability of red blood cells of rainbow trout (Salmo gairdneri R.)
Authors: Hughes G. M. , Kikuchi Y. 
Published: April 2021

ABSTRACT
Changes in haematocrit value are known to occur during hypoxia of rainbow trout and this has sometimes been interpreted as a result of an increase in red cell volume which is observed in vitro following equilibration with gas mixtures of low P02 (Black & Irving, 1938; Soivio, Westman & Nyholm, 1974). The possibility that there is also an increase in red cell number is still under discussion (Thomas & Hughes, 1982). The rise in blood haemoglobin content associated with such an increase would have physiological advantages for oxygen transport. However, an increase in haematocrit may increase resistance to blood flow and could impair the supply of oxygen at the tissue level. It is of interest, therefore, to know what are the effects of hypoxia both environmentally induced and under in vitro conditions on the flow properties of fish blood, for such effects have received little attention. This paper summarizes measurements of red cell deformability following changes from normoxic to hypoxic conditions, both in vivo and in vitro. A technique of filtration through a Nuclepore membrane has been used to provide an index of red cell deformability. During studies on yellowtail blood (Hughes, Kikuchi & Watari, 1982) variability in red cell deformability appeared to depend upon conditions of sampling and differences were observed in the filtration time of blood samples from normoxic and asphyxic fish. This effect has now been studied under more controlled conditions in rainbow trout.
A Cellular Mechanism of Classical Conditioning in Aplysia
Authors: Hawkins R. D. 
Published: April 2021

ABSTRACT
The defensive siphon and gill withdrawal of Aplysia is a simple reflex, mediated by a well-defined neural circuit, that exhibits sensitization in response to strong stimulation of the tail. The siphon withdrawal reflex also exhibits classical conditioning when a weak stimulus to the siphon or mantle shelf (the conditioned stimulus or CS) is paired with a shock to the tail (the unconditioned stimulus or US). Cellular studies indicate that the mechanism of this conditioning shares aspects of the mechanism of sensitization of the reflex : presynaptic facilitation due to a cAMP-mediated decrease in K+ current and consequent broadening of action potentials in the sensory neurones. Thus, tail shock (the US) produces greater facilitation of the monosynaptic EPSP from a sensory to a motor neurone if the shock is immediately preceded by spike activity in the sensory neurone than if it occurs without spike activity (sensitization), or if the shock and spike activity are presented in a specifically unpaired pattern. This activity-dependent amplification of facilitation involves a greater broadening of action potentials in paired than in unpaired sensory neurones and appears to be due to a greater depression of the same serotonin- and cAMP-sensitive K+ current involved in sensitization.
These results indicate that a mechanism of classical conditioning of the withdrawal reflex is an elaboration of the mechanism underlying sensitization. By analogy, the mechanisms of higher-order features of learning, such as the effect of contingency, may be built from combinations of the molecular mechanisms of these simple forms of learning.
The Structural Basis of an Innate Behavioural Pattern
Authors: Wine Jeffrey J. 
Published: April 2021

ABSTRACT
The abdominal nervous system of the crayfish contains six serially homologous ganglia, each containing approximately 650 neurones. No two ganglia are identical, and the ganglia interact extensively. Studies confined to intraganglionic interactions thus yield limited and sometimes misleading information. Each ganglion contains intrinsic (local) interneurones, motor neurones and projecting interneurones in roughly equal numbers, except in the specialized terminal ganglion where the ratio of these cells is approximately 3:2: 1. Although the number of nerve cell bodies in a ganglion is small enough to be tractable, integration occurs in the neuropile, which contains terminals from interneurones and afferents that outnumber the neurones originating in the ganglion by at least ten to one. The abdominal nervous system responds almost exclusively to a variety of mechanosensory stimuli. It has very limited light sensitivity. Other modalities, notably chemosensitivity, are undescribed and may be lacking. The effectors of the abdomen consist of fast axial muscles (used for tailflip-powered escape), slow axial muscles (for setting abdominal posture), appendage muscles (for swimmeret beating), and slow muscles of the intestine and rectum (that control gut emptying). The fast and slow muscles of the tailfan are specialized homologues of the axial and appendage muscles.
The abdominal nervous system represents only 3–4% of the 100000 neurones within the crayfish central nervous system (CNS). Most sensory information gathered in the abdomen is transmitted to the rostral CNS for processing, and many abdominal motor programmes are activated by descending commands. Nevertheless, a surprising degree of autonomy is present, and at least some motor programmes of every motor system can be activated in isolated abdomens.
Tailflip escape behaviour illustrates the integrative properties of the crayfish nervous system. Ninety pairs of efferents and eighteen pairs of interneurones have been identified within the abdominal portion of the escape circuit. A cell-by-cell analysis has so far provided neurophysiological explanations, in varying states of completeness, for ethological concepts such as innate releasing mechanisms, spatial patterning of movement, serial order in behaviour, and alterations in responsiveness to a constant stimulus.
From Embryonic Fascicles to Adult Tracts: Organization of Neuropile From a Developmental Perspective
Authors: Bastiani Michael , Pearson Keir G. , Goodman Corey S. 
Published: April 2021

ABSTRACT
We discuss ideas emerging from our studies on selective axonal fasciculation in the grasshopper embryo that have implications for the organization of the adult neuropile in insects and perhaps other animals. While one of our laboratories has been studying the embryonic development of the G neurone (in the mesothoracic segment) and its lineal homologues (in other segments), the other has been studying the morphology and physiology of this same neurone and its segmental homologues in the adult nervous system. Our embryonic studies show that the growth cone of the G neurone selectively fasciculates with the A/P fascicle in preference to all other longitudinal axon fascicles as it turns anteriorly. The homologues of G in other thoracic and abdominal segments fasciculate in this same bundle. However, early in their morphological differentiation, they reveal interesting segmental differences. Our studies on the adult nervous system show that the segmental homologues of the G neurone share many properties in common (e.g. axons in the LDT : lateral dorsal tract) while other features are quite different. The notion emerging from these studies is that a basic segmentally-repeated pattern arises during embryogenesis: a stereotyped axonal scaffold upon which growth cones faithfully fasciculate. Evolutionary plasticity allows the specialization of lineally equivalent neurones in different segments within the context of the neuropilar neighbourhood that they find themselves in as a consequence of their selective fasciculation.
Neurogenetics and Behaviour in Insects
Authors: Fischbach K. F. , Heisenberg M. 
Published: April 2021

ABSTRACT
The importance of the genome for behaviour has been amply demonstrated by the tools of population genetics. A deeper understanding of the relationship between genes and behaviour requires an investigation of how they influence brain development and neuronal function. This is the objective of neurogenetics.
Rigid genetic control of brain structure in insects is indicated by bilateral symmetry and by the similarity of isogenic brains (in locust). In large parts of the brain (e.g. optic lobes) the role of developmental variability seems to be as limited as in nematodes, but at closer inspection, the growth of at least some brain structures (e.g. mushroom bodies) is influenced by experience, similar to the growth of some vertebrate systems.
The role of individual genes for brain development and brain function is being studied in Drosophila melanogaster. Here, many single gene mutations affecting the brain and behaviour have been isolated. They either alter the development of neural circuits or modify cellular functions of neurones. Mutations of both categories are often remarkably specific (i.e. they influence only certain functional subsystems, leaving others unaffected). Therefore, functional subsystems are to some degree ontogenetic units under independent genetic control. Telling examples are sexual dimorphisms of behaviour and brain structure. The already peripheral separation of functional pathways in the brain seems to be partially due to the selective advantage of independent genetic modifiability of functions.
The Effects of Temperature on the Characteristics of the Dogfish Oculomotor System
Authors: Montgomery J. C. , Paulin M. G. 
Published: April 2021

Abstract
The dogfish oculomotor system can be modelled as a first order linear system (Montgomery, 1983) and hence can be specified by its characteristic frequency and gain. This paper describes the effect of temperature on these two parameters. The characteristic frequency is directly related to temperature, and decreases from 0·31 Hz at 20°C to 0·15 Hz at 10°C. The gain is inversely related to temperature, increasing approximately 2·5 times over a temperature drop from 20 °C to 10 °C. It is argued that the increase in gain with falling temperature can be attributed to an increase in relaxation time of the muscle, and that it is likely to be of biological significance in maintaining reflex performance in a poikilothermic animal.
Temporal and Spatial Spread of an Intersegmental Reflex in Crayfish
Authors: Page Charles H. , Gadaleta Dominick , Iacopino Anthony 
Published: April 2021

Abstract
An intersegmental reflex initiated by flexing a crayfish leg at the mero-carpal joint was examined by recording reflex response latencies of cephalic, thoracic and abdominal muscles. The first response was an intrasegmental resistance reflex in the extensor muscle of the stimulated leg. Spread of the intersegmental reflex occurred in both cephalic and caudal directions. Activation of the cephalic appendages occurred first (antennal levators, with latencies of 14–18 ms) while the abdominal musculature was activated last (superficial extensors, with latencies of 51–62ms). Shift of the stimulus site from the second to the fifth leg resulted in shorter latencies of the fifth leg and abdominal muscle responses while the latency for second leg extensor muscle discharge increased.
Low correlation coefficients between the response latencies of pairs of cephalic and abdominal muscles, and thoracic and abdominal muscles, indicate that reflex pathways which initiate the abdominal responses are different from those that evoke the cephalic and thoracic responses. High correlation coefficients indicate common reflex pathways for activating either ipsilateral or contralateral pairs of extensors or flexors in the second and fifth legs. High correlations suggesting common reflex pathways or cross-coupling were also obtained for bilateral pairs of abdominal extensors. Low correlation coefficients for the response latencies of paired muscles indicate separate reflex pathways for (1) bilaterally homologous leg muscles and (2) first–fifth segment abdominal extensors.
Surgical isolation of the supraoesophageal ganglion from the ventral nerve cord eliminated the responses of the antennal levators while producing a substantial increase in the response latencies of both maxilliped extensors and the contralateral second leg extensor and flexor, as well as a small but significant decrease in the contralateral first abdominal extensor. The synaptic input zones of the interneurones that mediate the thoracic and abdominal responses are located in the ventral nerve cord and not in the supraoesophageal ganglion.
Thermal Dependence of Contractile Properties of Red and White Fibres Isolated From the Iliofibularis Muscle of the Desert Iguana (Dipsosaurus Dorsalis)
Authors: Johnston Ian A. , Gleeson Todd T. 
Published: April 2021

Abstract
Single fibres were isolated from the ‘red’ and ‘white’ portions of the iliofibularis muscle from the desert iguana (Dipsosaurus dorsalis). Muscle fibres were chemically skinned with the non-ionic detergent Brij. 58.
Maximal Ca2+-activated tensions at 40°C were 32·3 ± 1·5 N cm-2 for red and 33·0 ± 24 N cm-2 for white muscle fibres (mean ± S.E. mean). Unloaded contraction velocities (Vmax) were determined by the ‘slack-test’ method. Average values for Vmax at 40°C were 7·1 ±0·4 and 164 ± 14 muscle length s-1 (Lo s-1) for red and white fibres respectively. The red portion of the iliofibularis contained fibres with Vmax values between 14 and 12·9 Los-1. Around 18% of the red fibre population had maximum contraction velocities less than 4·0Los-1. These slower fibres were principally located in the region closest to the femur in situ. They probably correspond to the multiply-innervated ‘tonic type’ fibres that can be identified histochemically.
Q10 values for Vmax over the range 5·15 °C were higher for red (4·2) than white (2·3) muscle fibres. Above 25·30 °C Q10 values for Vmax were in the range 1·3−1·9 for both fibre types. Maximum Ca2+-activated tensions were largely independent of temperature between 20 and 45 °C. Dipsosaurus is maximally active in the field at 35·42 °C, which corresponds to a 2one of relative thermal independence of muscle contractile properties and locomotory performance.
Oxygen Consumption and Swimming Performance in Hypoxia-Acclimated Rainbow Trout Salmo Gairdneri
Authors: Bushnell P. G. , Steffensen J. F. , Johansen K. 
Published: April 2021

ABSTRACT
Swimming performance and oxygen consumption of normoxic (control) and hypoxia-acclimated rainbow trout, Salmo gairdneri Richardson, were monitored at &gt;145, 60 and 40mmHg. Maximum swimming velocity at 40 mmHg was reduced from &gt;54·8cms−1 to 41·4cms−1 in controls and to 40·6cms−1 in hypoxia-acclimated fish. Normoxic oxygen consumption of control fish ranged from 97·5mg O2 kg−1 h−1 (5·5cms’1) to 318-5mg O2 kg−1 h−1 (54·8cms−1) and did not differ significantly from that of hypoxia-acclimated fish in normoxia. Reduction of ambient from normoxia to 60 mmHg or 40 mmHg did not significantly change oxygen consumption in control animals, although no fish (control or hypoxia acclimated) completed swimming trials at 54·8 cms−1 in 40mmHg. Oxygen consumption of hypoxia-acclimated fish at 5·5cms−1 and 40 mmHg was significantly higher than oxygen uptake in normoxia at the same speed. This relative increase was not maintained, however, as oxygen consumption at higher swimming speeds was similar to that in normoxia. Blood studies showed that hypoxia-acclimated fish had lower ATP concentrations and P50 values. While these factors may increase the blood oxygen loading capacity, the change is apparently not enough markedly to improve swimming performance or oxygen consumption in hypoxia and/or exercise.