bluuebunny/crossref_metadata_2025_split huggingface dataset:
Auditory Interneurones in the Metathoracic Ganglion of the Grasshopper Chorthippus Biguttulus: I. Morphological and Physiological Characterization
Authors: Stumpner Andreas , Ronacher Bernhard 
Published: April 2021

ABSTRACT
Auditory interneurones originating in the metathoracic ganglion of females of the grasshopper Chorthippus biguttulus can be classified as local (SN), bisegmental (BSN), T-shaped (TN) and ascending neurones (AN). A comparison of branching patterns and physiological properties indicates that auditory interneurones of C. biguttulus are homologous with those described for the locust. Eighteen types of auditory neurones are morphologically characterized on the basis of Lucifer Yellow staining. All of them branch bilaterally in the metathoracic ganglion. Smooth dendrites, from which postsynaptic potentials (PSPs) can be recorded, predominate on the side ipsilateral to the soma. If ‘beaded’ branches exist, they predominate contralaterally. The ascending axon runs contralaterally to the soma, except in T-fibres. Auditory receptors respond tonically. The dynamic range of their intensityresponse curve covers 20–25 dB. Local, bisegmental and T-shaped neurones are most sensitive to stimulation ipsilateral to the soma. The responses of SN1 and TNI to white-noise stimuli are similar to those of receptors, while phasic-tonic responses are found in SN4, SN5, SN7 and BSN1. The bisegmental neurones receive side-dependent inhibition that corresponds to a 20-30dB attenuation. One local element (SN6) is predominantly inhibited by acoustic stimuli. Ascending neurones are more sensitive to contralateral stimulation (i.e. on their axon side). Only one of them (AN6) responds tonically to white-noise stimuli at all intensities; others exhibit a tonic discharge only at low or at high intensities. One neurone (AN12) responds with a phasic burst over a wide intensity range. The most directional neurones (AN1, AN2) are excited by contralateral stimuli and (predominantly) inhibited by ipsilateral stimuli. Three ascending neurones (AN13–AN15) are spontaneously active and are inhibited by acoustic stimuli. All auditory interneurones, except SN5, are more sensitive to pure tones below 10 kHz than to ultrasound.
The Function of Spider Coxal Organs: Effects of Feeding and Salt-Loading on Porrhothele Antipodiana (Mygalomorpha: Dipluridae)
Authors: Butt A. G. , Taylor H. H. 
Published: April 2021

ABSTRACT
The contributions to ionic regulation of two putative excretory systems, the gut-derived anal system and the coelomoduct-derived coxal organs, were investigated in Porrhothele antipodiana. Coxal fluid was produced continuously during feeding. The fluid was transported anteriorly from the openings of the coxal organs on the coxae of walking legs 1 and 3, via a cuticular groove on the ventral surface of the cephalothorax, to the pre-oral region. The rate of production (70 μlg−1h−1) and normal composition of the fluid (Na+ 125, K+ 36mmoll−1) could account for the observed loss of Na+ into the prey remains during feeding and their final enrichment with Na+ relative to K+. In normally feeding spiders, coxal fluid was hypo-osmotic to the haemolymph. Salt-loading of the prey induced compensatory changes in both systems. Elevation of the Na+ or K+ content of the prey increased anal fluid excretion, the concentration of the corresponding ion in the stercoral fluid and thus the anal output of that ion. Likewise, dietary Na+-loading increased coxal fluid production and the [Na+] of the coxal fluid. K+-loading of the prey did not induce a regulatory response by the coxal organs. Spiders normally released coxal fluid only during feeding. Spiders that had been fed Na+-loaded prey produced coxal fluid intermittently for several days after the meal. Elevation of haemolymph [Na+] by injection of Na+ into the haemocoel also induced coxal excretion in non-feeding spiders, while having little effect on the volume and composition of the anal urine.
Clearance of inulin by the coxal organs was consistent with fluid production by ultrafiltration. It is concluded that in P. antipodiana both systems contribute importantly to ion and water balance and both contribute to the regulatory response to ion loading.
It is postulated that the coxal organs of P. antipodiana have an additional (perhaps primary) role in the mechanics of prey ingestion. Delivery of coxal fluid to the pre-oral region may facilitate the supply of predigested prey to the sucking stomach and prevent a rise in viscosity of the food by evaporative concentration. An auxiliary role for the anal urine is as a vehicle for nitrogenous excretion.
Arginine Kinase and Creatine Kinase Appear to be Present in the Same Cells of an Echinoderm Muscle
Authors: Ellington W. Ross 
Published: April 2021

ABSTRACT
Phosphagens are phosphorylated guanidine compounds which, via the catalytic action of corresponding phosphagen kinases, function as temporal and possibly spatial ATP buffers (Meyer et al. 1985) in cells capable of dramatic metabolic transitions such as muscle, neurons and spermatozoa. At least eight different phosphagen kinases have been identified and these enzymes are widely distributed throughout the animal kingdom (see excellent reviews by Van Thoai, 1968; Watts, 1968).
Reflex Pathways Responsive to Depression of the Locust Coxotrochanteral Joint
Authors: Skorupski Peter , Hustert Reinhold 
Published: April 2021

ABSTRACT
Resistance reflexes in arthropods are negative feedback reflexes broadly analogous to the vertebrate stretch reflex (Bush, 1962). Such reflexes may well be concerned with the maintenance of stable posture as a prerequisite for motor behaviour. Proprioceptors in the arthropod limb monitoring position and movement include muscle receptor organs and the chordotonal organs (see Mill, 1976, for reviews). In insects, an additional class of joint receptor has been described: the strand receptors (Bräunig and Hustert, 1980; Bräunig et al. 1981; Bräunig, 1982). The cell bodies of strand receptor primary afferent neurones are located within the segmental ganglia rather than at the peripheral sense organ.
The Whole-Body Withdrawal Response of Lymnaea Stagnalis II. Activation of Central Motoneurones and Muscles by Sensory Input
Authors: Ferguson Graham P. , Benjamin Paul R. 
Published: April 2021

ABSTRACT
The role of centrally located motoneurones in producing the whole-body withdrawal response of Lymnaea stagnalis (L.) was investigated. The motoneurones innervating the muscles used during whole-body withdrawal, the columellar muscle (CM) and the dorsal longitudinal muscle (DLM) were cells with a high resting potential (–60 to –70 mV) and thus a high threshold for spike initiation. In both semi-intact and isolated brain preparations these motoneurones showed very little spontaneous spike activity. When spontaneous firing was seen it could be correlated with the occurrence of two types of spontaneous excitatory postsynaptic potential (EPSP). One was a unitary EPSP that occasionally caused the initiation of single action potentials. The second was a larger-amplitude, long-duration (presumably compound) EPSP that caused the motoneurones to fire a burst of high-frequency action potentials. This second type of EPSP activity was associated with spontaneous longitudinal contractions of the body in semi-intact preparations. Tactile stimulation of the skin of Lymnaea evoked EPSPs in the CM and DLM motoneurones and in some other identified cells. These EPSPs summated and usually caused the motoneurone to fire action potentials, thus activating the withdrawal response muscles and causing longitudinal contraction of the semi-intact animal. Stimulating different areas of the body wall demonstrated that there was considerable sensory convergence on the side of the body ipsilateral to stimulation, but less on the contralateral side. Photic (light off) stimulation of the skin of Lymnaea also initiated EPSPs in CM and DLM motoneurones and in some other identified cells in the central nervous system (CNS). Cutting central nerves demonstrated that the reception of this sensory input was mediated by dermal photoreceptors distributed throughout the epidermis. The activation of the CM and DLM motoneurones by sensory input of the modalities that normally cause the whole-body withdrawal of the intact animal demonstrates that these motoneurones have the appropriate electrophysiological properties for the role of mediating whole-body withdrawal.
The Mechanism of Tongue Protraction During Prey Capture in the Frog Discoglossus Pictus
Authors: NISHIKAWA KIISA C. , ROTH GERHARD 
Published: April 2021

The mechanism of tongue protraction in the archaeobatrachian frog Discoglossus pictus was studied using high-speed video motion analysis before and after denervation of the submentalis and genioglossus muscles. The kinematics of prey capture were compared (1) between successful and unsuccessful feeding attempts before surgery; (2) before and after denervation of the m. submentalis; and (3) before and after denervation of the m. genioglossus. Prey capture by D. pictus is similar to that of Ascaphus truei, hypothesized to be the sister group of all other living frogs. These archaeobatrachians have tongues of limited protrusibility (maximum tongue reach=0.21-0.27cm) and lunge forward with the whole body to catch prey. In Discoglossus, unsuccessful attempts to capture prey differ from successful captures in having a longer duration of most kinematic variables. These results suggest that kinematic events are postponed in unsuccessful attempts at prey capture, owing to the absence of the somatosensory feedback that results from successful prey contact. Denervation of the m. submentalis prevents mandibular bending, but does not affect tongue protraction. Denervation of the m. genioglossus significantly decreases maximum tongue reach and maximum tongue height, but does not affect mandibular bending. The m. submentalis is necessary for mandibular bending, but neither mandibular bending nor m. submentalis activity are necessary or sufficient for tongue protraction. The m. genioglossus is necessary for normal tongue protraction. It does more than stiffen and support the tongue. These results are not consistent with the current model of tongue protraction developed for the neobatrachian toad Bufo marinus. If this model withstands the denervation test in Bufo marinus, then archaeobatrachians and neobatrachians must differ in their mechanisms of tongue protraction.
Note:
Present address: Brain Research Institute FB2, University of Bremen, D-2800 Bremen, Federal Republic of Germany.
Force-Velocity Relationships of a Locust Flight Muscle at Different Times During a Twitch Contraction
Authors: MALAMUD JEAN G. , JOSEPHSON ROBERT K. 
Published: April 2021

The force-velocity relationships during isotonic shortening were determined for the metathoracic second tergocoxal muscle of the locust Schistocerca americana (Drury). This muscle is a synchronous flight muscle. During the plateau of a tetanic contraction, the maximum shortening velocity (Vmax) determined from the force-velocity curve was 5.2 muscle lengths s−1 (25°C) and the curvature (a/Po) was 0.62. The maximum isometric force (P0) was 36.3 N cm−2.
Early in a twitch (at times shorter than the isometric twitch rise time) the values for Vmax and curvature were similar to those during the tetanic plateau, but the curves at different times during the twitch intercepted the force axis at values less than P0. Later in the twitch, Vmax declined.
A variable termed degree of activation (DA) is developed as a measure of the force-generating capacity of a muscle when this may be time-varying, as throughout most of a twitch. DA is determined from the shortening velocity at an intermediate load and is the predicted intercept of the force-velocity curve with the force axis relative to the tetanic intercept. In the locust muscle, DA rose to a maximum in 2–3 ms after the end of the latent period. DA reached 80° of the tetanic value during a single twitch; during the second twitch of a pair, the peak DA reached approximately the tetanic value. After a brief plateau, DA declined approximately exponentially. The time constant of DA decay was about 14 ms.
Note:
Present address: Department of Physiology, Emory University, Atlanta, GA30322, USA.
The Seasonal Variation in Biological Composition of Certain Plankton Samples from the North Sea in Relation to Their Content of Vitamin A, Carotenoids, Chlorophyll, and Total Fatty Matter
Authors: Gillam A. E. , El Ridi M. S. , Wimpenny R. S. 
Published: April 2021

ABSTRACTThe occurrence of relatively large stores of vitamin A in the liver oils of many fish has naturally aroused considerable interest in the ultimate origin of this source of the vitamin. From the results obtained by a number of workers, there is no doubt that many constituent organisms of the plankton exhibit the biological activity associated with vitamin A (Jameson et al. 1922; Hjort, 1922; Ahmad, 1930; Drummond & Gunther, 1930), but, whilst it is probable that the carotenoids produced (presumably photochemically) by certain phytoplanktonic organisms are converted into vitamin A itself in vivo in some of the organisms constituting the zooplankton, precise information as to the exact locale of this conversion is lacking. Thus, whilst shrimps (Hjort, 1922) and molluscs (Jameson et al. 1922) have been shown to exhibit the biological activity of vitamin A, some samples of zooplankton have been found to possess no activity of this nature at all (Drummond & Gunther, 1930, 1934).
The Maintenance of Reproductive Activity in Xenopus Laevis for Pregnancy Diagnosis
Authors: Landgrebe F. W. 
Published: April 2021

ABSTRACT
In 279 cases 97 % agreement was obtained between Zondek-Aschheim and Xenopus laevis pregnancy tests. Feeding once a week with either beef or liver is sufficient to maintain ovarian growth in Xenopus laevis but a diet of liver is more propitious if the frequency of feeding is less. The superiority of a liver diet is not due to its greater manganese or vitamin content. The effect of overcrowding upon the reproductive activity of Xenopus laevis is not due to pollution alone but also to some form of interaction between the animals themselves. The maximum density level compatible with ovarian growth is higher if the water is kept running than if it is only changed after feeding. Ovulation in Xenopus laevis as a response to injection of tissue extracts in doses up to 5 g. of tissue is specific to water extracts of the anterior lobe of the pituitary. Instructions for the technique of the Xenopus pregnancy test are outlined.
The Function of the Quintuple Innervation of A Crustacean Muscle
Authors: van Harreveld A. , Wiersma C. A. G. 
Published: April 2021

ABSTRACT
The functions of the five fibres innervating the flexor muscle of the carpopodite was investigated in Panulirus interruptus. The four thicker fibres were found to be motor axons, each eliciting a contraction with different characteristics. These four contractions were accompanied by four different types of action currents.
The thinnest fibre when stimulated simultaneously with any of the four motor fibres caused inhibition of the contraction.
It is concluded that all four contractions take place in all the muscle fibres and that the conception of the mechanism of crustacean nerve muscle system developed before is enlarged to include the new results. The possible biological significance of the quintuple innervation is discussed.
The Action of Drugs, Especially Acetylcholine, on the Annelid Body Wall (Lumbricus, Arenicola)
Authors: Wu K. S. 
Published: April 2021

ABSTRACT
In the course of a recently published investigation (Wu, 1939) it was found that the gut of the earthworm differed from the well-known preparation of the dorsal musculature of the leech (Fühner, 1918; Minz, 1932), as regards its reactions to acetylcholine, in the following respects: (1) in the absence of eserine the body wall of the leech is very much less sensitive to acetylcholine than is the gut (crop and gizzard) of the earthworm, the lowest effective concentration of the drug being 10−4 to 10−5 for the former and 10−5 to 10−10 for the latter; (2) treatment with eserine increases the sensitivity to acetylcholine of the leech dorsum enormously and that of the earthworm gut only slightly, so that the former (lowest effective concentration 10−8 to 10−10) is now nearly as sensitive as the latter (10−10 to 10−10); (3) adopting the classification of Dale (1914), the action of acetylcholine on the leech is a “nicotine-action” (abolished by large doses of nicotine) while that on the earthworm gut is a “muscarine-action’’ (abolished by small doses of atropine). The question therefore arises, are these differences due to the fact that we are dealing with two species, earthworm and leech, or with two organs, body wall and gut? To answer this question, the writer has studied the action of acetylcholine and certain other relevant drugs on the body wall of the earthworm (Lumbricus terrestris) and of the lugworm (Arenicola marina). By putting these results beside those already established for the leech, a comparison can be drawn between the reactions of the body wall in representatives of all of the three great divisions of the annelid phylum. As regards the gut, the data of Wu (1939) on the earthworm and of Wells (1937) on the lugworm are also available for comparison.
Studies on Living Protoplasm
Authors: Harris J. E. 
Published: April 2021

ABSTRACT
A study has been made of the rate of fall of the nucleolus through the nuclear fluid of echinoderm oocytes. Analysis of the results obtained on the oocytes of Echinus esculentus leads to the following conclusions :
The absence of sudden velocity changes during the fall indicates the absence of gross heterogeneities in the nuclear fluid. The nuclear fluid is thixotropic. Complete reconstitution of its elastic structure takes place within 10 min. of its disruption by the moving nucleolus. In addition to the gravitational force producing the fall, there is acting on the nucleolus a much weaker force, constant in magnitude and direction for any one oocyte. The presence of this additional force is indicated by a constantly reproducible difference in the rate of nucleolar fall in two opposing directions, and also by horizontal motion of the nucleolus during its fall. The force does not arise from viscosity differences in different regions of the nucleus ; the nuclear fluid is apparently homogeneous and has an absolute viscosity of approximately 0·1, i.e. 10 times that of water. Neither nucleolar asymmetry nor streaming of the nuclear protoplasm can account for the phenomenon. The electrical nature of the force on the nucleolus is suggested by the elimination of these possible mechanical explanations and by the presence of a surface charge on the nucleolus. The order of magnitude of the potential field required by this hypothesis is consistent with the energy output of the respiring oocyte. The polarized force on the nucleolus is abolished in M/500 potassium cyanide, and also by heating above 30° C. The bearing of these results on the structure of the nucleus and on the origin of polarity in the unfertilized egg is discussed.
The Significance of the Relationship between Actinians and Zooxanthellae
Authors: Smith H. G. 
Published: April 2021

ABSTRACT
Unicellular algae (zooxanthellae) occur in certain Actiniaria. The first important experimental work on the nature of the association was that of Brandt (1883 a, b), who starved anemones in Light and in darkness. From the results of these experi-ments he concluded that the animals obtained nutriment from the zooxanthellae when deprived of animal food. Later work by Boschma (1926) on Cribina xantho-grammica supports Brandt’s view. Brandt was unable to observe the digestion of the zooxanthellae and assumed that food material was passed in soluble form from algae to animal. By studying the mesenterial filaments of C. xanthogrammica Boschma brought forward evidence in favour of the view that zooxanthellae are actually digested by the anemone. In his opinion such actinians live partly on animal matter and partly on the zooxanthellae. During starvation they depend chiefly on the algae.
Response Properties and Adaptation of Neurones Sensitive to Image Motion in the Butterfly Papilio Aegeus
Authors: Maddess T. , Dubois R. A. , Ibbotson M. R. 
Published: April 2021

ABSTRACT
Wide-field direction-selective neurones from the optic lobes of the butterfly Papilio aegeus show some properties similar to those displayed by the large neurones of the fly lobula plate. Temporal and spatial frequency threshold tuning curves show that butterfly optic lobe neurones sensitive to different directions of image motion are fed by presynaptic subunits similar to those of the fly. However, unlike fly lobula plate neurones, the butterfly optic lobe neurones show a steep low-spatial-frequency roll-off which persists even at high temporal frequencies. Also exceptional is the temporal resolution of rapid changes in image speed by the butterfly neurones. When the cells are adapted to continuous motion their responses indicate a further increase in temporal resolution. Evidence is provided that in any one state of adaptation the neurones may be thought of as piece-wise linear and, thus, their responses can be predicted by convolution with a velocity kernel measured for that adaptation state. Adaptation to continuous motion results in the cells responding to motion in proportion to the mean motion signal. Motion in the non-preferred direction also appears to adapt the cells. Velocity impulse responses of both butterfly and blowfly neurones were determined with one-dimensional gratings and two-dimensional textured patterns and the results for the two stimuli are shown to be very similar.
Architecture of Cerebral Neurosecretory Cell Systems in the Silkworm Bombyx Mori
Authors: Ichikawa Toshio 
Published: April 2021

ABSTRACT
Anatomical and physiological characteristics of putative neurosecretory cells (NSCs) in the medial and lateral areas of the larval brain of Bombyx mori, identifiable by the opalescent appearance of their somata, were examined by means of intracellular recording and staining. Intracellular injection of Lucifer Yellow revealed that the medial cell group consisted of at least six subgroups of cells distinguishable by the geometry of their dendritic branches. Five subgroups of cells project axons to the contralateral corpus allatum (CA) or to the corpus cardiacum (CC). The remaining subgroup sends an axon to the ipsilateral ventral nerve cord. Three subgroups of cells were identified in the lateral group, projecting axons to the ipsilateral CC, to the CA or to the contralateral CA. Large and prolonged action potentials, similar to those recorded in some neurosecretory systems, were recorded from these medial and lateral cells. However, two pairs of medial cells containing paraldehyde-fuchsin-positive (neurosecretory) material and with axons extending to the contralateral nerve cord had action potentials of a short duration, more typical of non-NSCs such as tritocerebral cells innervating the stomodeal dilator muscles via the CC.