bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic Stimulation of the Ear of the Goldfish (Carassius Auratus)
Authors: Fay Richard R. , Popper Arthur N.
Published: April 2021

Microphonic potentials were recorded from the ears of the goldfish during acoustic stimulation in a situation where sound pressure and particle displacement could be varied. Microphonic potentials from fishes with the swim bladder intact were proportional to sound pressure. After removal of the swim bladder, sound pressure sensitivity declined by 20-35 dB and the response was generated in proportion to particle displacement. The ear’s sensitivity to direct vibration of the head increases at between −3 and −6 dB/octave between 70 and 1500 Hz and is not affected by the removal of the swim bladder. It is concluded that the peripheral auditory system of the goldfish may function as a pressure detector or as a displacement detector, depending upon the impedance of the applied signal.
The George Bidder Lecture 1973: Brains and Worlds: the Cerebral Cosmologies
Authors: Young J. Z.
Published: April 2021

I hope it may not be too ambitious to spend our time asking again the old question ‘What is the world really like?’ I shall bring you a little evidence of how Dr George Bidder himself regarded this question, and I like to think that with his strong and freely ranging mind he would have approved our attempt to tackle even these very difficult matters.
Increased RBC Count and Pulmonary Respiration in Cold-Adapted Frogs
Authors: Krishnamoorthy R. V. , Shakunthala N.
Published: April 2021

Haematological and respiratory parameters (including RBC count, CO2 content and percentage oxygen saturation) were studied in cold-acclimated (12 ± 1 °C) and normal frogs (23 ± 2 °C). Seasonal variation in RBC count was found, the count being higher in January than in September. Females showed higher counts than males. Cold-acclimation resulted in the elevation of counts in all seasons and in both sexes, and was accompanied by a rise in haemoglobin content. Cold-acclimated frogs retained a higher oxygen saturation in the truncus arteriosus than in the cutaneous vein, the carbon dioxide content of the truncus being also reduced in acclimated frogs. The O2/CO2 ratios were thus higher in the truncus than in the cutaneous vein. Cold-acclimated frogs released more 14CO2 through the lungs. It is suggested that a change in the mode of respiration occurs when the frogs are acclimated to cold.
Interrelationships Between Water and Metabolism in Artemia Salina Cysts: Hydration-Dehydration from the Liquid and Vapour Phases
Authors: Clegg James S.
Published: April 2021

Average weights of individual CaSO4-dried cysts (3·64 μg), shells (0·74 μg) and embryos (2·90 μg) of the brine shrimp, Artemia salina, were determined.’Residual water’ contents of these preparations were estimated to be 1·58 (cysts), 0·79 (shells), and 1·78 (embryos) in units of g H2O/100 g dried weight. Cysts hydrated to a similar degree in the liquid or vapour phase of NaCl solutions at o °C. Sorption isotherms revealed marked hysteresis for isolated shells, but not for entire cysts or the embryonic component. Adsorption data were plotted according to the Brunauer-Emmett-Teller equation and BET parameters were calculated and discussed. Cyst populations incubated at relative vapour pressures of water of 0·96 and above underwent a loss of dried weight, emerged in the hygrostats, and showed a decrease in viability. The foregoing did not occur at relative vapour pressures of 0·925 and below. The water content required for initiation of these events was estimated to be somewhere in the range of 46 to 72 g H2O/100 g dried cysts.
Eco-Physiological Studies of an Intertidal Crustacean, Pollicipes Polymerus (Cirripedia, Lepadomorpha): Aquatic and Aerial Respiration
Authors: Petersen J. A. , Fyhn H. J. , Johansen K.
Published: April 2021

Gas exchange in water and in air of the intertidal cirriped Pollicipes polymerus has been studied by combined field and laboratory experiments. Haemolymph gas tensions and pH are correlated with the tidal cycle in the field. Air exposure is accompanied by increasing oxygen and carbon dioxide tensions, and by decreasing haemolymph pH. During resubmersion the respiratory parameters are restored to values typical of the submerged state. There is no accumulation of lactic acid during air exposure. The oxygen uptake of Pollicipes is higher for air exposed than for submerged animals at each tested temperature. In air exposed animals the oxygen uptake shows a decreasing Q10 with increasing temperature between 2 and 27°C. Pollicipes exhibits oxygen conformity under varying ambient oxygen tensions and no oxygen debt is found after exposure to hypoxic water. The peduncle cuticle is permeable to oxygen and cutaneous respiration at this level may contribute significantly to the overall oxygen uptake. Pollicipes is well adapted to respiratory gas exchange both in water and in air making it a successful species in the intertidal community.
The Effect of Metabolic Inhibitors On the Cockroach Nerve-Muscle Synapse
Authors: Rees D.
Published: April 2021

The application of metabolic inhibitors to nerve-muscle synapses on ‘white’ and ‘red’ fibres in the retractor unguis muscles of P. americana and B. giganteus resulted in a dramatic increase in the spontaneous miniature potential discharge and was accompanied by a summation of the miniature potentials to form ‘composite’ potentials. Axon terminals associated with ‘white’ muscle fibres responded faster to metabolic inhibitors than those axon terminals associated with ‘red’ muscle fibres. Correlated ultrastructural and electrophysiological studies inferred that a tentative relationship existed between the miniature potential activities and synaptic vesicle distributions of the nerve-muscle synapses during the phases of metabolic inhibition.
The Possible Involvement of Brain Microtubules in Memory Fixation
Authors: Cronly-Dillon John , Carden David , Birks Carole
Published: April 2021

Goldfish were trained to discriminate between two coloured lights. When colchicine was administered intracranially immediately after training it produced complete retrograde amnesia 2 days later, but the fish displayed considerable retention if instead the injection was given 1·25 h after training. If colchicine was administered 1·25 h before training the fish were able to learn as readily as control fish but then showed retrograde amnesia when tested 2 days later. It is suggested that colchicine may affect memory fixation by interfering with the fast transport of material needed to bring about a structural modification at certain synapses.
Thermoacclimatory Variation in the Haemoglobin Systems of Goldfish (Carassius Auratus) and Rainbow Trout (Salmo Gairdneri)
Authors: Houston A. H. , Cyr D.
Published: April 2021

Significant increases in total haemoglobin concentrations, and microhaematocrit values were associated with acclimation of rainbow trout and goldfish to increased temperature. Goldfish held at 2°C were characterized by two haemoglobin components, whereas those acclimated to 20° and 35°C exhibited three. Nine haemoglobin variants were observed in trout at 2°, 10 ° and 18°C. The data provide evidence that both species selectively alter the concentrations of specific haemoglobin fractions during the thermoacclimatory process.
The Effect of Haemolymph Osmotic Pressure On the Meal Size of Nymphs of Locusta Migratoria L
Authors: Bernays E. A. , Chapman R. F.
Published: April 2021

Injection of trehalose into the haemolymph of Locusta nymphs reduced the amount of grass eaten in one meal. Greater effects were produced by higher concentrations and most reduction occurred when meals began 20 min after injection.

Sodium chloride, glycine, proline, sorbose, inulin or a mixture of solutes had similar effects.

The similarity of effects is explicable in terms of the increase in haemolymph osmotic pressure.

The increase in the osmotic pressure normally occurring during feeding is not great enough to affect the current meal.
Function of the Anuran Conus Arteriosus
Authors: Morris R. W.
Published: April 2021

The anuran conus arteriosus was studied by direct observation of its structure and function and by observing the effects of artificially induced contraction on the pressure pulse in the arterial arches. The beat of the anuran conus was found to close the outlet to the pulmocutaneous arches. The timing of the beat of the conus in the ventricular cycle is variable; early in the cycle the conus admits less blood to the pulmocutaneous circuit, more blood being admitted when it beats late. The timing of the beat of the conus appears to be adaptively related to beat frequency and to pH of the system. Elementary calculations suggest that these characteristics constitute an important measure of survival value of the anuran conus. The findings of this work are compatible with the theory of selective passage of two streams through the heart, supplementing such passage with additional control of blood volumes entering the pulmocutaneous circuit.
Some Auditory Discrimination Experiments On Marine Fish
Authors: Chapman C. J. , Johnstone A. D. F.
Published: April 2021

The ability of cod, Gadus morhua (L.), and haddock, Melanogrammus aeglefinus (L.), to discriminate changes in sound direction and amplitude was studied using a cardiac conditioning technique. In one experiment it was found that the masking effect of noise transmitted from one sound projector on the ability of the fish to detect a tone (60–380 Hz) transmitted from another projector was reduced by 7 dB when the angle between the projectors was 45° or greater. It was also shown that the fish could be conditioned to a change in the direction of a pulsed tone switched between two projectors. The fish were able to discriminate changes in sound amplitude of 1·3–9·5 dB at frequencies between 50 and 380 Hz. The results are discussed in relation to sound localization in fish.
Nitrogen Metabolism in the American Cockroach: An Examination of Whole Body Ammonium and Other Cations Excreted in Relation to Water Requirements
Authors: Mullins Donald E.
Published: April 2021

The effects of dietary nitrogen levels in relation to ammonotelism, cation excretion and water requirements were examined in the American cockroach, Periplaneta americana (L.). Very little ammonia is released from the respiratory surfaces; rather it appears to be eliminated in the faeces, presumably as ammonium ions. Microflora present in the hindgut may contribute significantly to the production of excreted ammonia under certain dietary conditions. Injections of buffers containing either NH4+, K+ or Na+ resulted in normal (NH4+ and K+), or less than normal (Na+) levels of ammonia excretion. Faeces collected from cockroaches maintained on twelve different diets containing various levels and sources of nitrogen were examined for NH4+, K+, Na+, Ca2+ and Mg2+. Ammonium ions were found to be the major cations contained in the faeces and were excreted in increasing amounts as the dietary nitrogen levels increased. The ad libitum water requirements were closely correlated with dietary nitrogen levels, and subsequently with ammonia excretion. Certain aspects concerning the possible factors involved, and the significance of ammonia excretion, are discussed.
Neuronal Homologies and the Control of Branchial Tuft Movements in Two Species of Tritonia
Authors: Dorsett D. A.
Published: April 2021

Comparative morphological and physiological studies of the branchial tuft retractor system of Tritonia hombergi and T. diomedia show a number of similarities and differences. In both species two homologous neurones in each pedal ganglion produce complete and partial contractions of the ipsilateral pinnae respectively.

Three pleural neurones cause bilateral contractions in T. hombergi: L Pl 6 and R Pl 5 inducing complete, and R Pl 6 partial, withdrawal of the tips. This differs from T. diomedia, where principal control is vested in the pleural giant cells.

The latency of tuft withdrawal declines and the rate of contraction increases with increasing impulse frequency in the retractor neurones, the musculature apparently responding to the second impulse of a series. After due allowance for conduction delays, only a small interval remains unaccounted for. Until electrical activity can be recorded from the musculature, the suggestion of the relay of central excitation through the peripheral plexus must be regarded as uncertain.
Kinetic Characteristics of Glycine Transport by the Isolated Midgut of the Marine Shrimp, Penaeus Marginatus
Authors: Ahearn Gregory A.
Published: April 2021

Mucosal glycine influx occurred via a single carrier-mediated, active transport entry process (Kt= 0·36 mm; Vmax = 0·42 μmoles/g. min) with an absolute Na+ requirement. Glycine transport inhibition by N2 gas, NaCN, NaN3, iodoacetate, 2,4-DNP, and ouabain was more extensive at 0·1 mm than at 1·0 mm glycine, suggesting a greater proportion of energy-dependent transport at lower amino acid concentrations. Aliphatic neutral amino acids and histidine were more potent inhibitors of mucosal glycine influx than were aromatic neutral, and anionic amino acids. Alanine was a fully non-competitive inhibitor of mucosal glycine entry, whereas proline appeared to be a fully competitive inhibitor of luminal glycine transfer. D-Fructose added to the incubation medium restored normal glycine transport in the presence of alanine, indicating that the two amino acids most likely utilized separate, energy-consuming, mucosal transport processes. A tentative model of glycine transport in the penaeid shrimp intestine is presented.
The effect of external sodium concentration upon sodium fluxes in Chironomus dorsalis (Meig.) and Camptochironomus tentans (Fabr.), and the effect of other ions on sodium influx in C. tentans
Authors: Wright D.A.
Published: April 2021

In comparison with other freshwater animals, the sodium uptake mechanism in fourth instar larvae of both C. tentans and C. dorsalis has a moderate affinity for sodium. In both species half maximum influx (Km) occurs at about 0·57 mm-Na+ and is unaltered by salt depletion. Maximum influx is achieved in steady-state C. tentans at 1·9 mm-Na+, and in steadystate C. dorsalis at 3·0 mm-Na+. Both of these values increase on depletion. Efflux also appears to be saturable at higher external sodium concentrations.

In C. tentans, sodium may be transported independently of chloride, although it seems likely that sodium movement is enhanced by chloride. Sulphate strongly inhibits sodium influx. Nitrate apparently inhibits sodium influx at low concentrations, but this inhibition is progressively overcome at external sodium concentrations approaching 4 mm.

A number of cations interfere with sodium influx in depleted C. tentans, notably H+, Li+ and, to a lesser extent NH4+. It is suggested that these ions compete with sodium for carrier sites. Potassium is apparently transported independently of sodium.
Sodium and lithium movements and axonal function in cockroach nerve cords
Authors: Bennett R.R. , Buchan P.B. , Treherne J.E.
Published: April 2021

Exposure to sodium-deficient (tris) saline caused an appreciable decline in the sodium content of intact connectives in the absence of equivalent reduction in the amplitude of the recorded action potentials. Return of sodium-depleted connectives to normal saline resulted in a rapid recovery of axonal function despite only a partial ( < 70%) recovery in sodium content. Replacement of sodium ions by those of lithium in the bathing medium resulted in a substantial accumulation of this cation. Lithium movements exhibited a marked asymetry, no significant decline in concentration being observed upon return to normal saline. These results are tentatively interpreted in terms of an exchangeable glial sodium fraction and are discussed in relation to extra-axonal sodium regulation.
Transport of Exogenous D-glucose by the Integument of a Polychaete Worm (Nereis Diversicolor Müller)
Authors: Ahearn Gregory A. , Gomme Jørgen
Published: April 2021

Integumentary exchange of radio-labelled D-glucose in the brackish-water polychaete worm Nereis diversicolor (Annelida; Polychaeta) was investigated. In animals acclimated to 50% sea water, the influx of D-glucose was measured, and shown to occur largely across the outward-facing membranes of the epidermal cells. Transfer of exogenous D-glucose across the outer membranes occurs by facilitated transfer, involving two different transport systems. One of these has a Kt (transport constant) of ≃ 5 μM, i.e. of the order of magnitude of environmental D-glucose concentrations. The Kt for the other system is at least ten times higher. The D-glucose is rapidly metabolized by the epidermal cells. Small amounts of unmetabolized D-glucose are released to the extracellular fluid, and probably to the medium. The maximal D-glucose outflux through the apical border of the epidermal cells is at least 4 times smaller than the outflux through the baso-lateral border. A maximum value is given for the diffusion permeability of D-glucose through the intercellular spaces of the integument. Applying this figure, the loss by intercellular diffusion was found not to exceed the D-glucose influx into the epidermal cells.
Transport of amino acids by isolated gills of the mussel Mytilus californianus Conrad
Authors: Wright S. H. , Johnson T. L. , Crowe J. H.
Published: April 2021

The unidirectional influx of cycloleucine into in vitro preparations of gill tissue of the mussel, Mytilus califomianus, was determined. Influx was found to be linear for at least an hour, and the kinetics of cycloleucine influx conformed to Michaelis-Menten type kinetics. The transport mechanism(s) for cycloleucine is relatively specific for the L-enantiomorph of neutral amino acids, and is capable of accumulating cycloleucine to intracellular concentrations much higher than those of the surrounding medium. Evidence is presented that the transport of amino acids by gill tissue plays a significant role in whole animal nutrition.
Factors affecting the heart activity and blood pressure of the swan mussel Anodonta cygnea
Authors: Sommerville B. A.
Published: April 2021

The rate of heart beat increased with temperature and was three times as high in the active as in the inactive animal. The rate of shell valve movement rose and the rate of heart beat fell when the foot was extended. The rates of heart beat and shell valve movement decreased when the water was saturated with carbon dioxide. This heart response remained when the visceral ganglion was destroyed. Ventricular contraction occurred simultaneously over the whole chamber. The passage of blood into the posterior aorta could be restricted by the protuberances on its wall. Pericardial cavity pressure rose by about 5 cm H2O at shell valve adduction and 0·25–0·6 cm H2O at ventricular diastole. Pulse pressure changes of 0·25–0·6 cm H2O occurred in the auricle and 1–3 cm H2O in the ventricle and anterior aorta.
Modes of stimulation of the teleost ear
Authors: Fay R. R. , Popper A. N.
Published: April 2021

Microphonic potentials were recorded from the inner ears of a catfish (Ictalurus punctatus) and an African mouthbreeder (Tilapia macrocephala) in response to underwater sound stimulation and direct vibration of the head. The shape of the vibratory isopotential functions of frequency was similar in both species up to 600 Hz. Above 600 Hz, the sensitivity of Ictalurus continued to increase to 4000 Hz while the sensitivity of Tilapia declined.

Deflation of the swim bladder did not affect the response to vibration in either species, the response of Tilapia to the underwater sound stimulus being minimal and unaffected by removal of the swim bladder.

Ictalurus was pressure-sensitive to above 4000 Hz, there being a significant decline in the response with deflation of the swimbladder.
The transmission of impulses in the ectodermal slow conduction system of the sea anemone Calliactis parasitica (Couch)
Authors: Shelton G. A. B.
Published: April 2021

The SS 1 fatigues in response to repetitive electrical stimulation. This fatigue is manifested by an increased conduction delay and a decreased SS 1 pulse amplitude. Continued repetitive stimulation leads to the failure of the system. Recovery may take many seconds. Narrow strips of column fail more rapidly than wide strips. The increased conduction delay is explained in terms of a decrease in the population of spiking cells. A computer model is described and analysed. It suggests that conduction between electrically coupled ectoderm cells could be the basis for the SS 1. The SS 1 may have properties not so far experimentally demonstrated; for example, under certain conditions it could behave as a local system.
An in vitro bioassay for a molluscan gonadotropin
Authors: Wells M. J. , O’Dor R. K. , Buckley S. K. L.
Published: April 2021

Protein synthesis occurs at a high rate in the ovaries of maturing Octopus vulgaris and can be measured from the incorporation of [14C] leucine in vivo and in isolated groups of eggs in vitro. Removal of the optic glands in vivo 1–3 days prior to testing markedly reduces amino acid incorporation in vivo or in vitro. After 5 days in vivo incorporation stops. The rate of incorporation in vitro is increased by the addition of optic gland extract. Analysis of the kinetics of leucine uptake and incorporation in vitro indicates that the hormone has an effect on the inward transport of leucine which is independent of its action on protein synthesis. Electron-microscope studies of the follicle cells and ova show that the former are the site of protein synthesis. Changes in either uptake or incorporation into protein by the follicle cells can be used as a qualitative biological assay for the optic gland hormone. Uptake is very easy to measure but incorporation is the more sensitive parameter. Either is potentially suitable as a quantitative assay for this and perhaps also for other molluscan gonadotropins.
Corpus allatum activity in vitro during ovarian maturation in the desert locust, Schistocerca gregaria
Authors: Tobe S. S. , Pratt G. E.
Published: April 2021

Radiochemical in vitro assays show that there are large and rapid changes in the spontaneous rate of juvenile hormone synthesis and release during the course of sexual maturation in the locust. Parallel observations on glands incubated with farnesenic acid show that the rate-limiting step is always prior to the stage of esterification of farnesenic acid to the final intermediate, methyl farnesoate. Corresponding changes in oocyte morphometrics do not reveal any clear correlation between endocrine activity of the corpus allatum and either the induction or maintenance of rapid vitellogenesis. Peaks of synthetic activity in the corpus allatum correspond well with the onset of previtellogenic growth in the oocytes. The data do not provide any evidence that ‘corpus allatum insufficiency’ is responsible for resorption of growing oocytes. It is concluded that short-term in vitro radio-assays provide a valid method for estimating quantitatively the physiological activity of the corpus allatum.
The Mechanism of Statocyst Operation in the Mysid Shrimp Praunus Flexuosus
Authors: Neil D. M.
Published: April 2021

Analysis of the compensatory eyestalk responses of mysid shrimps before and after the removal of one statocyst has revealed, in the light of statocyst anatomy, that the two statocysts co-operate in their action at all angles of body tilt.Many features of statocyst operation in mysids are shared by decapod crustaceans, but an important difference exists between the geometries of the two statocyst systems. The consequences of this difference highlight the structural constraints on systems of statolithic gravity receptors for which shear magnitude is the adequate stimulus.
Problems associated with the use of tetraethylammonium to test for monosynaptic connexions
Authors: Berry M. S. , Pentreath V. W.
Published: April 2021

Several investigators of the molluscan nervous system have used TEA, injected into presynaptic neurones, to determine whether the connexions made by these neurones are monosynaptic. The increase in spike duration produced by the TEA causes an increase in transmitter release, and hence an increase in the amplitude of the postsynaptic potential if the connexion is direct. If the connexion is indirect, the spike in an intercalated neurone will not be affected by the TEA, and the postsynaptic response will remain constant. Experiments described here show that TEA can cross electrotonic junctions in the gastropod mollusc Planorbis comeus. They also show that each TEA-prolonged presynaptic impulse may produce more than one postsynaptic impulse. A larger postsynaptic potential could therefore be produced by presynaptic injection of TEA in the case of an indirect connexion. This indicates that care must be taken when interpreting the results of experiments using TEA to test for monosynaptic connexions.
The control of diuresis in the tsetse fly Glossina austeni: a preliminary investigation of the diuretic hormone
Authors: Gee J. D.
Published: April 2021

The rate of secretion of the Malpighian tubules of Glossina austeni is controlled by a diuretic hormone. This hormone is present in the nervous tissue of the fly together with a degradative enzyme that can be inactivated by boiling. It is demonstrated that the Malpighian tubules are able to destroy the diuretic hormone; they may therefore participate in the control of diuresis. The diuretic hormone appears to be a heat-stable, non-dialysable, alcohol-soluble molecule, containing amino acid, glucose and sialic acid residues.
Localization and electrical activity of the distance chemoreceptors that mediate predator avoidance behaviour in Acmaea limatula and Acmaea scutum (gastropoda, prosobranchia)
Authors: Phillips David W.
Published: April 2021

The marine gastropods Acmaea (Collisella) limatula and Acmaea (Noto-acmea) scutum respond to distant predatory starfish (i.e. to starfish scent) by moving up a vertical surface. The distance chemoreceptors that mediate this avoidance behaviour are located on the mantle margin. Heat cauterization of the limpets’ mantle margin eliminates their responsiveness to Pisaster ochraceus scent, while a similar cauterization of the ctenidium and the osphradia does not diminish the avoidance behaviour. Primary afferent electrical activity can be recorded from the chemo-receptors on the mantle margin that are responsive to starfish scent and also from other physiologically distinct receptors that are responsive to contact with starfish tube feet.
The innervation of the salivary gland of the moth, Manduca sexta: evidence that dopamine is the transmitter
Authors: Robertson H. A.
Published: April 2021

Using the Falck-Hillarp histochemical technique for monoamines, evidence was found for the presence of a catecholamine in the salivary gland nerves of the moth, Manduca sexta. The innervation was studied with the electron microscope. Only the fluid-secreting region of the gland is innervated and the nerve endings are characteristic of monoamine-containing terminals. Using a sensitive enzymatic-isotopic assay for catecholamines, it was found that whole salivary glands contain 0·33 μ g/g dopamine but no nor-adrenaline. It seems likely that dopamine mediates fluid-secretion in the salivary gland of Manduca as it does in a number of other arthropods.
Regeneration of peripheral nerves to supernumerary legs in cockroaches
Authors: Westin J. , Camhi J. M.
Published: April 2021

Clusters of legs were grown from metathoracic coxae of the cockroach. Legs of a cluster had different segmental origins, sizes, and orientations. Regenerating metathoracic nerves tended to enter the nearest leg, and to a lesser extent of the largest leg, but showed no significant tendency to penetrate metathoracic rather than prothoracic legs, or normally oriented rather than abnormally oriented legs. Movements of legs were evoked by nerve stimulation significantly more often in nearest, largest, and normally oriented legs, but were equally frequent in prothoracic and metathoracic legs. Close proximity of peripheral nerves is not required for the differentiation of the legs, since nerves were visible in the legs only at the later stages of their development, and many of the legs were apparently never innervated.
Motor innervation within supernumerary legs of cockroaches
Authors: Westin J. , Camhi J. M.
Published: April 2021

Clusters of legs having prothoracic and metathoracic origins were grown from the metathoracic coxa of the cockroach. Of these legs, those which were innervated contained only one, or occasionally two, of the three major nerves innervating the cockroach leg. Stimulation of a particular leg nerve (no. 3, 5 or 6) evoked movement at the same joints and in the same directions in a leg having only one nerve as in a normal leg. Stimulation of a particular metathoracic nerve generally produced the same movements in a prothoracic leg transplanted to the metathoracic site as it did in a regenerated or intact metathoracic leg.
The branchial chloride pump in the goldfish Carassius auratus: relationship between Cl-/HCO3- and Cl-/Cl- exchanges and the effect of thiocyanate
Authors: de Renzis G.
Published: April 2021

The effect of thiocyanate on chloride and sodium fluxes across the gill was studied in the goldfish Carassius auratus. At low external chloride concentrations, addition of SCN− to the bathing solution markedly inhibited chloride influx and efflux, the net flux being reversed. SCN− injection was without effect. SCN− had no effect on sodium fluxes when injected or added to the external medium. The inhibition of chloride influx by SCN− was of a mixed type involving simultaneous modifications of the affinity constant of the carrier for Cl− and of the maximal Cl− influx. The affinity constant of the carrier for SCN− was 10 times lower than that for Cl−. The gill of the goldfish was found to be practically impermeable to SCN−. In the presence of external SCN−, the C1−/HCO3− exchange was reversed : Cl− was lost against HCO3− which is absorbed. This suggests an obligatory exchange. Exchange diffusion for chloride was also demonstrated. A kinetic model is proposed to explain chloride and bicarbonate transport across the gill of Carassius auratus.
An automatic respirometer for determining oxygen uptake in crayfish (Austropotamobius pallipes (Lereboullet)) over periods of 3-4 days
Authors: Sutcliffe D. W. , Carrick T. R. , Moore W. H.
Published: April 2021

An automatic respirometer has been developed for continuous measurements over 3–4 days on 1–15 g crayfish. The sensor is a modified Mack-ereth oxygen electrode. Respiration is recorded on a millivolt potentiometric pen recorder during closed periods when the O2 concentration in the medium falls to a predetermined level. A solenoid-operated valve is then opened via a relay circuit energized by a reed switch mounted on the recorder. Medium flows through the respirometer until the O2 concentration is raised back to another predetermined level. Artificial media containing little or no nutrient salts are used to restrict the growth of microbes. Respiration was determined chiefly on crayfish (Austropotamobius pallipes) with body wet weights of 7·0–12·5 g at 10·0°C. In unrestrained but relatively quiescent animals, standard metabolism is described by the regression equation, In O2 uptake = 3 ·3037 +1 ·002 In body wt. In restless crayfish active metabolism is described by the equation, In O2 uptake = 4 ·4412 + 0 ·861 In body wt.
Co-ordinating interneurones of the locust which convey two patterns of motor commands: their connexions with ventilatory motoneurones
Authors: Burrows M.
Published: April 2021

The interneurones which make widespread connexions with flight motoneurones also synapse upon ventilatory motoneurones so that in all 50 motoneurones receive synapses. They influence three aspects of ventilation; (a) the closing and opening movements of the thoracic spiracles, (b) some aspects of abdominal pumping movements and (c) the recruitment of some motoneurones controlling head pumping. The two closer motoneurones of a particular thoracic spiracle receive the same excitatory synaptic inputs (EPSPs) during expiration. The EPSPs match those in appropriate flight motoneurones. The closer motoneurones of each thoracic spiracle whose somata are in the pro-, meso-or metathoracic ganglia all receive the same excitatory synaptic inputs. These inputs are an adequate explanation of the pattern of spikes in the closer motoneurones. Both the slow ventilatory and fast rhythms of synaptic potentials are expressed as spikes; the slow as the overall expiratory burst of spikes and the fast as the groups of spikes within that burst. This establishes a ventilatory function for the interneurones. All thoracic closer motoneurones therefore receive the same excitatory commands which will tend to synchronize the movements of each spiracle. Spiracular opener motoneurones are inhibited during expiration, their IPSPs matching the EPSPs in flight or closer motoneurones. Therefore the interneurones have reciprocal effects on the antagonistic motoneurones of the spiracles. The interneurones synapse upon some motoneurones which control the pumping movements of the abdomen and which have their somata in the metathoracic or first unfused abdominal ganglion. Motoneurones in four separate ganglia therefore receive inputs from these interneurones. The interneurones also synapse upon motoneurones which control an auxiliary form of ventilation, head pumping.
The action of the excretory apparatus of Calliphora vomitoria in handling injected sugar solution
Authors: Knowles G.
Published: April 2021

Recent evidence suggests that the isolated Malpighian tubules of Calliphora possess mechanisms which restrict the loss of glucose and trehalose from the insect. This report establishes that the intact, diuresing fly does not excrete glucose or trehalose when solutions of these sugars are injected. When solutions of non-metabolized sugars such as sorbose and xylose are injected into the fly, these sugars are rapidly excreted. High concentrations of sorbose and xylose are found in the urine, suggesting that rapid reabsorption of fluid occurs in the excretory apparatus even during the diuresis which the injections provoke. However, injected sucrose is apparently not excreted in large amounts and it is possible that the Malpighian tubules when functioning in vivo are impermeable to disaccharides.
The receptive fields of Daphnia ommatidia
Authors: Young S. , Downing A. C.
Published: April 2021

The focal length and positions of the principal planes of an isolated Daphnia lens were determined, and the refractive index of the rhabdom was measured. The lens can form an image, but this always lies well behind the rhabdom. This was confirmed by direct observation of images inside a clear-eye mutant Daphnia eye. The rhabdom was shown to be unlikely to function as a waveguide, and a ray optics model is proposed to enable the prediction of ommatidial receptive fields from the lens data. The predicted receptive fields have wide plateaus and steep sides, and there are virtually no totally blind gaps between neighbouring ommatidia.
Properties of the trochanteral hair plate and its function in the control of walking in the cockroach
Authors: Wong R. K. , Pearson K. G.
Published: April 2021

The physiological properties of the group of long hair sensilla of the trochanteral hair plate in the cockroach metathoracic leg were studied. The sensilla were divided into type I and type II according to their responses to imposed displacements. Type I hair sensilla responded to dynamic displacements whereas type II hair sensilla responded to both dynamic and static displacements. The hair sensilla are normally excited by phasic flexion movements of the femur near the end of leg protraction. Activity in the trochanteral hair plate afferents had a short latency excitatory effect on the motoneurone producing slow extension movements of the femur and an inhibitory effect on the femur flexor motoneurones. Removal of the trochanteral hair plate in one leg caused overstepping of that leg in a walking animal due to exaggerated flexion of the femur. This change in leg movement can be explained by the removal of the inhibitory influence from the hair plate afferents to the femur flexor motoneurones. We conclude that one function of the trochanteral hair plate is to limit femur flexion during a step cycle.
Printed circuit microelectrodes and their application to honeybee brain
Authors: Pickard R. S. , Welberry T. R.
Published: April 2021

The application of printed circuit technology to the production of a new type of multi-channel microelectrode is described. Recordings have been obtained from the protocerebrum of the honey bee Apis mellifera L. using printed circuit microelectrodes in both restrained and free-moving preparations. These recordings are compared with those previously obtained from conventional probe microelectrodes and are found to have similar characteristics of transient voltage changes superimposed on an undifferentiated high frequency background. A wide range of development possibilities for the printed circuit microelectrode are discussed.
Horomonal control of larval diapause and metamorphosis of the southwestern corn borer Diatraea grandiosella
Authors: Yin C. M. , Chippendale G. M.
Published: April 2021

Changes in haemolymph juvenile hormone (JH) concentrations of larvae of the southwestern corn borer, Diatraea grandiosella, were used to estimate the activity of the corpora allata. The haemolymph of penultimate nondiapause instars contained a maximum JH titre of 3000 Galleria units (GU)/ ml, whereas the titre in the final instar had dropped to 140 GU/ml within 6 h of the ecdysis and continued to remain low. Corpora allata of last-stage nondiapause larvae therefore remain inactive. Some signal other than a rapidly declining JH titre in mid-instar triggers the release of ecdysiotropin because the pupal moulting cycle did not become independent of the brain and ecdysial glands until 4·25 and 4 ·75 days after the final larval ecdysis, respectively. Newly diapaused immaculate larvae had a haemolymph JH titre of ca. 1500 GU/ml. Three JH mimics applied to early last stage non-diapause larvae induced the formation of the immaculate diapause morph. The mimics did not activate the recipient’s corpora allata, but elevated the functional JH concentration, each having a different intrinsic hormonal activity. Threshold JH concentrations which control larval ecdyses, diapause maintenance, and metamorphosis are presented.
Studies on the mechanism of fluid secretion by isolated salivary glands of Calliphora
Authors: Berridge M. J. , Lindley B. D. , Prince W. T.
Published: April 2021

Previous studies on isolated salivary glands of Calliphora have concentrated on the role of cyclic AMP and calcium in mediating the action of 5-hydroxytryptamine (5-HT) (Berridge, 1970; Berridge & Prince, 1972a, b; Prince & Berridge, 1972, 1973; Prince, Berridge & Rasmussen, 1972). Electrophysiological studies suggested that cyclic AMP stimulated a cation pump whereas calcium increased anion permeability. The role of calcium in altering membrane permeability has been confirmed by measuring the resistance of both the apical and basal membranes during the action of 5-HT (Berridge, Lindley & Prince, 1975 a). These resistance measurements have been used to develop a model which adequately accounts for all the potential changes normally observed during the action of 5-HT. The basis of this model depends on having an active pump on the apical membrane which transports potassium from the cell into the lumen. Chloride follows passively. Potassium and chloride transported from the cell into the lumen is replaced by a passive influx of these ions across the basal plasma membrane into the cell.
A method for recording the respiratory and hatching movements of the chick embryo
Authors: Dawes C. M.
Published: April 2021

An artificial air space was made in the narrow end of the pipped egg by separating the shell membranes from the shell. The respiratory and hatching movements of the embryo set up pressure changes within the artificial air space and these were recorded up until the moment when the chick emerged from the shell. Random movements appeared to be inhibited during the period of hatching. The ways in which the presence of the artificial air space might affect the embryo have been discussed.
Some Advanced Flight Manoeuvres of Bats
Authors: Norberg Ulla M.
Published: April 2021

Two manoeuvres in bats are described: rolls through 180°, in Nyctalus noctula, and a series of sideslips in Otomops martiensseni. These manoeuvres cause a rapid loss of height. They are initiated by pronation of one wing and supination of the other. After the roll, when the bat is in an upside down position, the lift force of the wings is directed downwards, causing a tight turn downwards (apparently for insect catching). During sideslip the body drag of the bat is increased. This reduces the total lift/drag ratio, thus steepening the equilibrium gliding angle.
Responses of trout gill ion transport systems to acute acidosis
Authors: Kerstetter T. H. , Mize R.
Published: April 2021

The response of rainbow trout Na+ and Cl− uptake systems to acute acidosis was tested by slow infusion of lactic acid into anaesthetized animals. Depression of blood pH by 0·4 pH unit had no effect on influx rates for either ion, and we conclude that gill ion uptake systems do not respond rapidly to blood pH changes.
Polarization variations induced by high hydrostatic pressures in the isolated frog skin as related to the effects on passive ionic permeability and active Na+ transport
Authors: Pequeux A.
Published: April 2021

The effects of a wide range of hydrostatic pressures (from 50 to 1000 kg/cm2) have been investigated on the spontaneous potential difference (PD), the short-circuit current (SCC) and the activity of the membrane ATPases of the isolated abdominal skin from the frog Rana temporaria L. Two types of variations in PD are induced by pressure changes: short and transient potential variations which appear to be related to the pressure change (compression and decompression) and lasting variations which persist as long as pressure is applied and whose nature appears to be related to the pressure magnitude.

Long-lasting potential changes have particularly been investigated. At pressures lower than 500 kg/cm2, the skin potential increases while a pressure over 500–600 kg/cm2 induces a depolarization. Both variations consecutively occur at 500 + 100 kg/cm2. These effects of pressure have been shown to be reversible up to about 800 kg/cm2.

The question of the origin of the potential changes is discussed and it is proposed that the lasting hyperpolarization results from an effect on the passive permeabilities to Na+, K+ and Cl- ions inducing in turm a secondary readjustment (stimulation) of the Na+ active transport while the depolarization at high pressures reflects a direct inhibition of the Na+ pump.

These interpretations are supported by experimental data on the effects of pressure on the short-circuit current and on the activity of the skin (Na+ + K+) ATPase.
Ultrasonic Clicks Produced by the Peacock Butterfly: A Possible Bat-Repellent Mechanism
Authors: Møhl Bertel , Miller Lee A.
Published: April 2021

Torpid peacock butterflies (Inachis io) produce intense ultrasonic clicks that startle captive vespertilionid bats (Plecotus auritus and Pipistrellus pipistrellus). The clicks occur as the wings are opened and are generated by a stiff portion of wing membrane between the costal and subcostal veins near the base of the forewing. The power spectrum of a click matches the most sensitive area of a bat’s audiogram. Clicks may serve as acoustic equivalents of the attack-retarding eyespot display in the same species.
Elastic energy storage in primary feather shafts
Authors: Pennycuick C. J. , Lock A.
Published: April 2021

It is proposed that the kinetic energy of a pigeon’s wing, in hovering or slow forward flight, is transferred to the air at the end of the downstroke by a mechanism involving temporary storage of additional energy in bent primary feather shafts. Estimates of the amounts of energy which can be stored and recovered in this way are compared with the requirements of the theory. The hypothesis is not rejected, as far as present evidence goes. If it is correct, high-velocity pulses of calculable magnitude should be detectable in the wake.
The influence of various factors on fluid secretion by in vitro salivary glands of ixodid Ticks
Authors: Kaufman W.
Published: April 2021

Salivary glands of the female ixodid tick, Dermacentor andersoni, secrete fluid in vitro when bathed in a slightly modified version of the mammalian tissue culture medium ‘TC 199’. Rate of salivation in vitro increases with progression of feeding, but there is no comparable increase in dry weight of the salivary glands during the early phase of engorgement. Engorged ticks secreted at only 25 % the rate of 90−250 mg ticks, indicating that salivary gland degeneration has already begun in the very early post-engorgement stage. A salivary gland stimulating factor can be detected in the nervous system but not in other tissues. Male salivary glands secrete at only 1/20th the rate of female glands. Thus males probably do not use their salivary glands as osmoregulatory organs. From the uniform lack of response to ACh and uniform response to DA in 7 ixodid tick species, it is suggested that the control of salivation is similar throughout the ixodid family.
Anatomy and development of the somatic musculature of the nematode Ascaris
Authors: Stretton A. O.
Published: April 2021

The musculature of the nematode Ascaris has been studied by the examination of serial sections by light and electron microscopy. The muscle cells of nematodes are unusual in that they send branches to the neurones in contrast to the more usual situation in other animals where neurones send processes to the muscles. The neuromuscular synapses are made at the ends of the arms. Muscle cells receive multiple innervations and perform integration of the combined inputs. The action potentials are initiated near the ends of the arms so each arm acts as an integrative centre. It is shown that it is common for a muscle cell to have several arms, raising the possibility that each arm may integrate different combinations of neuronal inputs.

In the second larval stage the total number of muscle cells is 83. The adult has approximately 5 × 104 muscle cells. The very striking increase in cell numbers of the musculature is not matched by a corresponding increase in the number of cells in the nervous system. A model for the way in which a small number of neurones can co-ordinate the activity of an increasing population of muscle cells is presented.
The Coordinate Roles of Branchial Nerve Activity and Potassium in the Stimulation of Ciliary Activity in Mytilus Edulis: Observations with Phenoxybenzamine, Bromolysergic Acid and Fluorescence Histochemistry
Authors: Paparo Anthony A.
Published: April 2021

Potassium concentrations in excess of 30 mm increase the rate of beating of lateral cilia on the gill of Mytilus edulis. Cilioexcitation produced by low frequency (5 beats/s) electrical stimulation was potentiated with potassium but blocked with bromolysergic acid (a serotonergic inhibitor). Cilio-inhibition produced by high frequency (50 beats/s) stimulation was decreased with potassium and phenoxybenzamine (a dopaminergic inhibitor). Phenoxy-benzamine enhanced the cilioexcitation produced by potassium. Potassium doses incapable of maintaining a basal rate of beating (< 30 mm) could increase ciliary activity if phenoxybenzamine was also added. After transection of the branchial nerve, the yellow-fluorophore (serotonergic storage) and cilioexcitatory effect of potassium gradually decrease.

This study shows that the potassium effect on ciliary activity (a) increases with low frequency nerve stimulation, presumably through the release of serotonin and (b) decreases with high frequency nerve stimulation, presumably through the release of dopamine.