bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Chemical Composition of Muscle Tissue
Authors: Robertson James D. 
Published: April 2021

ABSTRACT
Mantle muscle from Sepia officinalis, Loligo forbesi and Eledone cirrhosa has been analysed for all the major constituents contributing to its osmotic concentration, including inorganic ions, organic phosphates, amino acids and nitrogenous bases. Intracellular concentrations have been calculated for Sepia and Eledone muscle after appropriate corrections for extracellular fluid as measured by inulin space. From analyses of the juice pressed from muscle it has been concluded that the whole of the cell calcium, much of the magnesium and sodium, and a lesser proportion of potassium is bound to cell constituents ; the chloride ion is completely free. Direct measurements of the osmotic concentration of muscle-juice and plasma of Eledone show that the juice is slightly hyperosmotic (+ 3·2% on plasma value), probably owing to some breakdown of labile compounds. The ions and compounds studied make up 94% of the osmotic concentration of the muscle cells in Sepia, and 86 % in Eledone. Over half of the osmotic concentration of the cells is made up by free amino acids, trimethylamine oxide and betaine.
Ion and Water Transport in Isolated Intestine of the Marine Teleost, Cottus Scorpius
Authors: House C. R. , Green K. 
Published: April 2021

ABSTRACT
The unidirectional sodium fluxes from mucosa to serosa and from serosa to mucosa have been studied in the isolated small intestine of Cottus scorpius, bathed in Ringer and sulphate Ringer, by use of the isotope 22Na. In addition the unidirectional chloride fluxes have been studied in Ringer and choline Ringer using the isotope 36Cl. In Ringer the mean ± S.E. values of these fluxes have been found to be: for sodium, 8·4+ 0·6 (serosa to mucosa) and 23·9+0·7 (mucosa to serosa) /μequiv. cm. -2 hr. -1 and for chloride, 10-5 ± 0-9 (serosa to mucosa) and 21·9 ± 0·9 (mucosa to serosa) μequiv. cm. -2 hr. -1. In sulphate Ringer the mean ± s.E. values for sodium were 4‘5 ± 0·3 (serosa to mucosa) and 6·8 ± 0·6 (mucosa to serosa) /μequiv. cm. -2 hr. -1 and in choline Ringer the mean ±S.E. values for chloride were 5·1 ± 1·0 (serosa to mucosa) and 5·94 + 0·9 (mucosa to serosa) /μequiv. cm. -2 hr. -1. The respiration rates of pieces of intestine placed in Ringer, sulphate Ringer, choline Ringer and artificial sea water have been measured in a Warburg apparatus. The mean ±S.E. values of oxygen consumption in these media have been found to be 0·4 ± 0·2 (Ringer), 0·3 ± 0·2 (sulphate Ringer), 0·3 ± 0·2 (choline Ringer) and 0·1 ±0·2 (artificial sea water) μ1. O 2/mg. dry weight.hr. The electric potential differences between identical serosal and mucosal media bathing isolated intestines have been measured. The mean + s.E. values of the potential difference in Ringer, sulphate Ringer, choline Ringer and artificial sea water have been found to be +0·6 ± 0·3, +2·2 ± 0·2, + 0·8 ±0·3 and +1·3+ 0·2 mV., respectively (mucosal medium taken as reference). The hydraulic conductivity of the isolated intestine has been found by measuring the change in net water flux arising from the creation of an osmotic gradient across this tissue. Net water flux was measured by the change in weight of normal filled sacs. The mean + s.E. value for this parameter has been found to be 0·22 ± 0·05 μ1/cm. 2 mosmolar. hr. (or 2·4+0·6 cm. sec. -1 atm. -1). It has been found that, when artificial sea water is placed in the lumen of the intestine bathed in Ringer, a net flow of water into the lumen occurs. This net water flux falls to zero at a time dependent on the luminal volume (to be diluted) and, thereafter, a net water flux (mucosa to serosa) is established. The net water movement across isolated intestines bathed on both sides by identical media has been studied. The mean ± s.E. values for net water flux (mucosa to serosa) have been found to be: in Ringer, 8·1±0·8, in sulphate Ringer, 3·6±0·5 and in choline Ringer, 6·7 ± 0·6 µ. cm. -2 hr. -1. The results are interpreted as showing that the net transfer of sodium and chloride ions between identical Ringer solutions is achieved by some process whereby these ions are ‘pumped’ in the form of electrically neutral sodium chloride. It is considered that there is some evidence for the existence of a frictional interaction between sodium chloride and water as they pass across the intestine.
Respiratory Movements in Holothuria Forskali Delle Chiaje
Authors: Newell R. C. , Courtney W. A. M. 
Published: April 2021

ABSTRACT
The respiratory rate of Holothuria forskali has been found to be between 0·0162 and 0·0465 ml. O2/g. dry wt./hr. at 17° C. By separating the water pumped by the cloaca from that in contact with the general body surface it is found that cloacal gas exchange accounts for approximately 60% of the total uptake of oxygen by the animal. Uptake of oxygen through the cloaca occurs only when the pumped water is more than 60−70% saturated with air. At lower concentrations there is no exchange through the respiratory trees and no corresponding increase in absorption through the general body surface. Pumping rhythms in intact H. forskali are described. It is shown that there are three main types. In all types the rate of pumping increases as the oxygen in the pumped water becomes depleted. At concentrations corresponding to 60-70% air-saturation, however, pumping ceases and this coincides with the observed reduction in cloacal gas exchange. It is shown that a period of reduced gas exchange through the cloaca is followed by increased uptake of oxygen when pumping is resumed. Measurements of the coelomic oxygen concentration shows that cessation of pumping is followed by a rise in the oxygen concentration in the coelomic fluid. The function of the coelomic oxygen reservoir is discussed.
The Relative Losses of Sodium in the Urine and Across the Body Surface in the Amphipod, Gammarus Duebeni
Authors: Lockwood A. P. M. 
Published: April 2021

ABSTRACT
The suggestion has previously been made (Lockwood, 1961) that the rapid change from isotonic to hypotonic urine production which occurs when Gammarus duebeni is transferred from a high concentration (100−175 % sea water) to fresh water may subserve the function of slowing the loss of ions from the body. Any such slowing would decrease the rate of fall of the blood concentration and hence allow additional time for the necessary concomitant changes in cellular osmotic pressure to be brought about. The ability to slow the rate of ion loss for this purpose might be of functional significance to this species as it is often found in environments such as salt-marsh pools which may be subject to sudden and extensive variations of salinity.
Urine Formation in A Pulmonate Land Snail, Achatina Fulica
Authors: Martin A. W. , Stewart D. M. , Harrison F. M. 
Published: April 2021

ABSTRACT
Inulin is filtered into the urine of Achatina fulica. The process is not subject to poisoning but water reabsorption may raise the U/B ratio to 2·8. The U/B ratios of substances actively reabsorbed or secreted reaches 1 when transport is poisoned thus verifying filtration as a first step in urine formation. Exogenous urea is excreted by filtration. Glucose is filtered and actively reabsorbed. Reabsorption can be poisoned with phlorizin. Chloride is actively reabsorbed. Phenol red and PAH are actively secreted. The secretory process may be poisoned with dinitrophenol. The clearance of phenol red may be taken as an estimate of blood flow through the kidney, which may reach 5·6 ml./min./kg. in Achatina fulica. The PAH clearance is depressed by simultaneous excretion of phenol red and the quantitative measurements of transport give evidence that the same secretory mechanism is used for both phenol red and PAH.
Muscular Activity During Preparation For Flight in A Beetle
Authors: Leston Dennis , Pringle J. W. S. , White D. C. S. 
Published: April 2021

ABSTRACT
The sound produced during the pre-flight activity of the water beetle Acilius sulcatus (L.) consists of a train of pulses, implying that there is a click mechanism present in the thorax when the wings are folded. The pulse frequency rises as the temperature rises. Analysis of the sound oscillograms reveals some differences from the analogous system in cicadas which can be correlated with differences in anatomy. The sinusoidal (inertial) and pulsed modes of operation of insect fibrillar muscle are alternative ways in which oscillatory activity can be generated. They result from a single property of this type of muscle and occur when it is coupled, respectively, to an inertial or to a clicking load.
The Activity of Single Motor Fibres in Arthropods: I. The Dragonfly Nymph
Authors: Knights Ann 
Published: April 2021

ABSTRACT
Responses to mechanical and electrical stimulation have been investigated in single motor fibres dissected in the segmental nerves of the dragonfly nymph. A large proportion of fibres possessed a background discharge which was often accelerated or inhibited on stimulation. Examples of central inhibition were common. Efferent responses varied in type, delay and regularity, both with the input under stimulation and with the frequency and intensity of the volley. The majority of fibres responded to stimulation of more than one nerve root. In many motor fibres changes in the parameters of stimulation demonstrated a reciprocal relationship between intensity and frequency. An enhanced responsive-ness occurred with frequency increases in the range of 10 −100/sec. indicating a considerable importance of temporal summation/facilitation. The characteristic frequency-sensitivity of motor fibres and the variability of their response patterns are discussed in relation to the control of insect muscle.
Cardiac Output in the Large Cephalopod Octopus Dofleini*
Authors: Johansen Kjell 
Published: April 2021

ABSTRACT
The high level of structural organization displayed by the cardiovascular system of cephalopods promises a similar complexity in its functional organization. In spite of an extensive literature on this subject most of the work is old and inadequate in techniques and experimental procedures (Fuchs, 1895; Fredericq, 1914). The only physiological parameters hitherto recorded of any value for the evaluation of cardiovascular dynamics have been arterial and venous blood pressures (Johansen & Martin, 1962).
Larval Diapause of Maternal Origin: Induction of Diapause in Nasonia Vitripennis (Walk.) (Hymenoptera: Pteromalidae)
Authors: Saunders D. S. 
Published: April 2021

ABSTRACT
The environmental factors responsible for the induction of larval diapause in Nasonia vitripennis are photoperiod, temperature and host deprivation. They are effective during the life of the female parent and not during larval development. Short daylength and low temperature induce females to produce diapause larvae early in reproductive life and long daylength and high temperature avert diapause. Conditions of darkness are ‘intermediate ‘in this respect. The effects of daylength are reversible during the life of the female. Females switch from the production of developing to diapause larvae during their reproductive life, so that a distinct age pattern is apparent. The two strains of Nasonia used in this investigation showed different patterns of diapause production. Although this difference is shown to be under ultimate genetic control, the mechanism of in duction is purely maternal and the males play no part in determining the diapause characteristics of their immediate progeny. Unlike other cases of photoperiodic induction of larval diapause, the mechanism cannot operate solely through the central nervous system and a chemical ‘factor’ (a hormone?) passed from the parent female through the egg to the larva is postulated.
Haemodynamics in Tresus Nuttallii and Certain Other Bivalves
Authors: Smith L. S. , Davis J. C. 
Published: April 2021

ABSTRACT
Blood pressures were measured in the hearts and aortas of several bivalves. Systolic pressures in the ventricles were commonly O-5-2-O mm. Hg, while diastolic pressure was zero. The aortic bulb produced pressures similar to those produced by the ventricle, but beat less frequently and not in synchrony with the ventricle, except in the isolated heart. Pericardial and auricular pressures were normally undetectable, except that small pressure pulses were recorded in the auricle during experimentally produced increases in venous return. Aortic pressure sometimes exceeded ventricular pressure, although unusually strong contractions of the body muscles raised aortic pressures far above that in the ventricle. The heart does not provide pressure for extension of siphons or foot. Sea water pumped by isolated Tresus ventricles demonstrated that neither pericardium nor auricles are needed for ventricular filling, as had been hypothesized earlier. The morphology of the heart walls supports the concept of bivalve hearts as being a site of filtration, with the ventricle thought to play a larger role than the auricles. Valves in the heart and aortas which control direction of blood flow are described.
Automatic Activity of the Locomotor Centres of the Lumbar Cord in Lizards
Authors: Ten Cate J. 
Published: April 2021

ABSTRACT
My previous experiments with salamanders (Triton cristatus;ten Cate, 1927) and tortoises (Testudo graeca;ten Cate, 1937) have shown that, after transection of the spinal cord in the thoracic region, locomotor movements of the hind limbs can be observed under favourable conditions while the front limbs remain motionless. These alternating movements are well co-ordinated but last only a short time; the front limbs then also begin to move.
The Function of A Heteromorph Antennule in A Spiny Lobster, Panulirus Argus*
Authors: Maynard D. M. , Cohen M. J. 
Published: April 2021

ABSTRACT
The effects of electrical and mechanical stimulation upon a ‘naturally occurring ‘heteromorph appendage growing in place of one eyestalk in Panulirus argus were examined. The heteromorph resembled the outer flagellum of the antennule in form. Heteromorph stimulation elicited both a generalized withdrawal response, and a specific depression of the third segment and flagellum of the ipsilateral antennule. Such a depression response was also elicited upon stimulation of the ipsilateral outer flagellum of the normal antennule and by no other input investigated. The basic similarity of the two responses was confirmed by electromyography and by intracellular recordings from motor neurons and interneurons within the lobster brain. It was concluded that at least one afferent fibre component from the heteromorph and normal flagellum terminated upon the same interneuron pools, while avoiding others, and that consequently these observations provide evidence for the formation of functional inter-neuronal connexions according to type specificity.
Reflex Control of Abdominal Flexor Muscles in the Crayfish: I. The Twitch System
Authors: Kennedy Donald , Takeda Kimihisa 
Published: April 2021

ABSTRACT
The polyneuronal innervation of crustacean muscles has been well explored in decapod limbs, both comparatively at the level of entire muscles (Wiersma & Ripley, 1952) and, by means of single motor axon stimulation and microelectrode recording, at the level of single muscle fibres (Fatt & Katz, 1953 a, b; Furshpan, 1955; Hoyle & Wiersma, 1958). Experiments of the latter sort have shown that motor axons produce excitatory junctional potentials (e.j.p.s) that may or may not give rise to active electrogenic events (spikes). The e.j.p.s evoked by different motor axons may differ in amplitude, rate of rise or fall, and tendency to facilitate upon repetitive stimulation; axons that evoke more sharply rising e.j.p.s exhibiting little facilitation have been termed ‘fast’, and others ‘slow.’
Electrical Activity in the Radial Nerve Cord and Ampullae of Sea Urchins*
Authors: Sandeman D. C. 
Published: April 2021

ABSTRACT
A single shock applied through wick electrodes to the isolated radial nerve cord of a sea urchin produces a recordable potential in the cord. The potential is conducted along the cord at a velocity of between 14 and 20 cm./sec. The potential is complex and graded. Two components of the potential can be identified and have different thresholds to stimulation, conduction velocities and amplitudes. They are believed to represent two classes of fibres. The potential is conducted decrementally along the cord and normally cannot be recorded at distances greater than 60 mm. from the stimulus. The amplitude of the potential decays logarithmically falling to half after 7 mm. spread. There is no facilitation of amplitude or distance of spread. Potentials initiated simultaneously at either end of the isolated nerve cord collide and partially occlude each other. Stimulation of a side branch of the nerve cord evokes potentials recordable from only ipsilateral neighbouring side branches and the whole cord. However, contractions of the contralateral ampullae following stimulation of lateral branches reveal spread of the excitation beyond the region of recordable potentials. A single shock to a cord still attached to the test causes contraction of the associated ampullae. One ampulla will contract several times after a single shock, a period of relaxation following each contraction. Electrical activity recorded from the ampullae, and lasting many seconds after the single shock, corresponds with their contractions. The activity is believed to be muscle action potentials. Evidence of a feedback from damaged tube feet to the cord, suppressing ampulla response to cord stimulation, was found.
Studies on the Mode of Action of the Diapause Hormone in the Silkworm, Bombyx Mori L
Authors: Hasegawa Kinsaku , Yamashita Okitsugu 
Published: April 2021

ABSTRACT
Glycogen synthesis in the ovary of Bombyx mori is accelerated by the diapause hormone. Such glycogen is derived, by way of the trehalose of the haemolymph, from carbohydrate in the fat body. Extirpation of the suboesophageal ganglion has the converse effect: a fall in glycogen in the ovary and an increase in blood trehalose and fat-body glycogen. Mobilization of fat-body glycogen is dependent on the presence of the ovaries, and of the suboesophageal ganglion. The same results can be obtained in male pupae after the implantation of ovaries. These observations on carbohydrate metabolism confirm the belief that the ‘target organ ‘of the diapause hormone is the ovary itself. The changes in other tissues are due to feedback.
Circulation in A Giant Earthworm,Glossoscolex Giganteus
Authors: Johansen Kjell , Martin Arthur W. 
Published: April 2021

ABSTRACTThe annelid worms stand out among most other invertebrate forms by having a closed vascular system. Their blood usually contains haemoglobin in simple solution as a respiratory pigment. Some of the earthworms as a subdivision of this phylum may attain considerable size weighing more than 500–600 g., and may be as long as 120 cm. with a maximum diameter of 2–3 cm. It is surprising to find that the earthworm Glossoscolex giganteas of such great size has no special organs of respiration, the skin being the only surface available for gas exchange. Such a structural arrangement may depend upon specialized adaptations in the pattern of blood flow or in the respiratory characteristics of the blood, or both.
The Site and Permeability of the Filtration Locus in the Crayfish Antennal Gland*
Authors: Kirschner Leonard B. , Wagner Stanley 
Published: April 2021

ABSTRACTInulin (MW 5000) and two dextrans (MW 15,000–20,000 and 60,000–90,000) appear in the urine of crayfish after injection into the blood. All three compounds are more concentrated in the urine than in blood, indicating that water is reabsorbed from a filtrate formed within the antennal gland. Inulin and the low molecular weight dextran seem to be handled in the same fashion since their urine/blood concentration ratios are about the same. However, the high-molecular-weight dextran is excreted only about 70% as effectively as the other pair. This suggests that filtration of polymers in the MW range 50,000-100,000 is restrained. Excretion of human serum albumin occurs but it is even more severely restricted than the large dextran. Mammalian globulin (MW about 180,000) and crayfish blood protein are not excreted in the urine. Blood protein becomes concentrated in the coelomosac. Localization of fluoescein-labelled mammalian globulin shows that the peritubular cells in the coelomosac are the main sites of protein accumulation. Concentration of blood protein in the coelomosac suggests that filtration occurs in this region, but the intracellular location suggests that the filtration mechanism differs from that in the vertebrate nephron.
The Effect of Photoperiod on the Developmental Rate of Drosophila Pupae
Authors: Harker Janet E. 
Published: April 2021

ABSTRACT
The time taken for Drosophila melanogaster to complete three stages of pupal development has been measured for pupae entering each stage at each particular hour of the day in cycles of 12 hr. light: 12 hr. darkness, 4 hr. light:20 hr. darkness, 18 hr. light:6 hr. darkness. Similar measurements have been made for insects in which the larvae were subjected to the light cycles but the pupae remained in constant darkness. The duration of each stage is affected by the time of day, relative to the light cycle, at which the stage is entered. When pupae are in constant darkness the developmental rate of each stage is affected by the time of day at which the stage is entered relative to the particular light cycle to which the larval stage had been exposed. The eclosion rhythm, which arises as a summation effect of rhythms of development at earlier stages, may become bimodal in light cycles with suitable photofractions. The rate of development of a pupa entering a stage during the light period is related to the time-interval since the light-on signal ; the preceding dark period has no effect. The developmental rate of pupa entering a stage during the dark period is affected by the time-interval since the light-off signal, but may also be affected by the previous light-on signal although there is no simple relationship between them. As the developmental rates are maintained in constant darkness it is concluded that the rate of development is affected by factors following a diurnal rhythm. The form of the rhythm is determined by both light-on and light off signals, but the timing of the rhythm is determined by the two signals acting independently of each other.
Observations on the Absorption of Water, Diapause and Embryogenesis in the Eggs of the Cricket Teleogryllus Commodus (Walker)*
Authors: Browning T. O. 
Published: April 2021

ABSTRACT
The eggs of Teleogryllus commodus absorb water only when the embryo has reached a particular stage of development. Water is absorbed just before the development of the embryo reaches the stage at which diapause occurs. Preventing the absorption of water prevents the further development of the embryo. These results are discussed in relation to other information on water absorption and diapause in the eggs of insects.
Pressure and Volume Relationships in the Ventricle, Conus and Arterial Arches of the Frog Heart
Authors: Shelton G. , Jones D. R. 
Published: April 2021

ABSTRACT
Peak systolic pressures in the ventricle, conus and arterial arches differ by 1 or 2 mm. Hg only, and are reached at the same time. Pulse pressures are largest in the ventricle and smallest in the arterial arches, though their relationship to one another is variable and depends partly on heart rate. The conus continues to contract after relaxation of the ventricle. Blood flow from the heart occurs during four-fifths of the cardiac cycle and stops with the closure of the valves at the top of the conus. Volume changes in the conus are 5–10% of those seen in the ventricle. The conus is filled early in ventricular systole before the peak pressure is reached. The ventricle does 20 to 40 times more work than the conus in ejecting blood from the heart. The conus does not serve a depulsating function or make a major contribution to blood outflow from the heart in anurans.