bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tail Muscle Activity Patterns in Walking and Flying Pigeons (Columba Livia)
Authors: Gatesy Stephen M. , Dial Kenneth P. 
Published: April 2021

ABSTRACT
The electrical activity of major caudal muscles of the pigeon (Columba livia) was recorded during five modes of aerial and terrestrial locomotion. Tail muscle electromyograms were correlated with movement using high-speed cinematography and compared to activity in selected muscles of the wings, legs and trunk. During walking, the pectoralis and most tail muscles are normally inactive, but levator muscle activity alternates with the striding legs. In flight, caudal muscles are phasically active with each wingbeat and undergo distinct changes in electromyographic pattern between liftoff, takeoff, slow level flapping and landing modes. The temporal flexibility of tail muscle activity differs significantly from the stereotypic timing of wing muscles in pigeons performing the same flight modes. These neural programs may represent different solutions to the control of flight surfaces in the rapidly oscillating wing and the relatively stationary caudal skeleton. Birds exhibit a novel alliance of tail and forelimb use during aerial locomotion. We suggest that there is evidence of anatomical and functional decoupling of the tail from adjacent hindlimb and trunk muscles during avian evolution to facilitate its specialization for rectricial control in flight.
Giant Fiber Activation of an Intrinsic Muscle in the Mesothoracic Leg of Drosophila Melanogaster
Authors: Trimarchi James R. , Schneiderman Anne M. 
Published: April 2021

ABSTRACT
Cinematographic analysis reveals that an important component of the light-elicited escape response of Drosophila melanogaster is the extension of the femur–tibia joint of the mesothoracic leg. During the jumping phase of the response, this extension works synergistically with extension of the femur. Femur extension is generated by contraction of the tergotrochanteral muscle (TTM), one of four previously described escape response muscles.
Femur–tibia joint extension in the mesothoracic leg has been thought to be controlled by contraction of the tibial levator (TLM), an intrinsic leg muscle. We investigated the activation of the TLM during the escape response. Electrical stimulation of the giant fiber interneuron that mediates the escape response results in activation of the TLM with a latency of 1.46±0.02ms. The TLM is innervated by a motor neuron (TLMn) with a large cell body in the mesothoracic ganglion. The TLMn has extensive arborizations in the lateral mesothoracic leg neuromere and has a prominent medially directed neurite. To investigate possible presynaptic inputs activating the TLMn during the escape response, we analyzed the muscle responses of two mutants, giant fiber A1 and bendless. Our analysis suggests that the TLMn is activated by a novel pathway.
Discontinuous Carbon Dioxide Release in the Eastern Lubber Grasshopper Romalea Guttata and its Effect on Respiratory Transpiration
Authors: Hadley Neil F. , Quinlan Michael C. 
Published: April 2021

ABSTRACT
Ventilatory patterns were examined in the Eastern lubber grasshopper Romalea guttata and correlated with respiratory transpiration. Discontinuous release of CO2 was only observed in quiescent individuals during their scotophase. Interburst periods (spiracles closed) alternated with bouts of CO2 emission and O2 consumption (burst phase); no true ‘flutter’ phase was observed. Cycle duration decreased with increasing temperature in both hydrated and dehydrated individuals. Metabolic rates for this large, sluggish species are lower than those reported for smaller and/or more active grasshoppers. Water loss rates fell within an expected range of values for arthropods from mesic environments. Respiratory transpiration accounted for only 1.9–3.9% of the total water loss between 15 and 30 °C and for only 7% of the water loss during the burst phase of the cycle. These data indicate that the cyclic release of CO2 in this adult insect does not result in substantial savings of water.
Identification of β-Like Adrenoceptors Associated With Bioluminescence in the Sea Pansy Renilla Koellikeri
Authors: Awad Edward W. , Anctil Michel 
Published: April 2021

ABSTRACT
Previous studies have reported pharmacological and biochemical evidence for the involvement of adrenergic substances in the regulation of neuroeffector activities in the bioluminescent cnidarian Renilla koellikeri (Cnidaria, Anthozoa). Therefore, direct radiobinding assays were developed to identify and characterize β-adrenergic binding in membrane preparations from this species, using the two β-antagonists [3H]dihydroalprenolol and [3H]CGP12177 as tracers. In addition, the effect of various β-adrenergic agents on luminescence was examined. Binding of the radioligands at 25°C was rapid, reversible, saturable and specific. Saturation studies revealed the presence of two different and independent classes of binding site, site1 and site2, in the body of the colony (rachis). In contrast, homogeneous populations of binding sites corresponding to site1 were detected in autozooid polyps and to site2 in the peduncle. The pharmacological profile of β-adrenergic binding in R. koellikeri membrane preparations displayed properties consistent with the presence of two sites and followed a pattern similar to β2-and β1-adrenergic receptor subtypes for site1 and site2, respectively. Bioluminescence in polyps was induced by β-agonists as well as by one β1-selective antagonist, atenolol, and was blocked by several β-blockers including (±)CGP12177. The specificity pattern of the physiological effect of β-adrenergic drugs on luminescence mirrors that of the radioligand interaction with site1. This suggests that radioligand binding to site1 represents binding to the receptor that mediates luminescence excitation in R. koellikeri. Blockade of the luminescent responses to site1 agonists by isotonic MgCl2 indicates that this β-adrenergic mechanism must rely on interneuronal transmission. Collectively, these results suggest the evolutionary conservation of β-adrenoceptors and of their dual character from coelenterates to higher vertebrates.
Akh Biosynthesis: Transcriptional and Translational Control of Two Co-Localised Prohormones
Authors: Fischer-Lougheed Jacqueline , O’Shea Michael , Cornish Ian , Losberger Christophe , Roulet Emmanuelle , Schulz-Aellen Marie-Francoise 
Published: April 2021

ABSTRACT
The neurosecretory cells of the locust corpora cardiaca (CC) express two co-localised transcripts which are translated into the two preprohormones required in adipokinetic hormone I (AKH I) and AKH II biosynthesis. At different stages of postembryonic development, the relative amounts of the two transcripts (AKH I mRNA and AKH II mRNA) change in parallel with the relative rates of synthesis of proAKH I and proAKH II. Differential regulation of transcript expression, however, cannot account for the changes in neuropeptide ratios seen during postembryonic development. Comparison of in vivo and in vitro translation shows that protein synthesis in vivo is biased towards the translation of AKH I mRNA by a factor of about 2.6. This factor appears to be constant during postembryonic development and is required to produce the observed developmental changes in neuropeptide ratios. Both transcriptional and translational mechanisms are therefore necessary to alter neuropeptide ratios in the CC. The mechanisms we describe can account for the developmentally changing pattern of peptide expression. We suggest that regulation of neuropeptide ratios indicates that signalling functions can be attributed to the precise configuration of peptide cocktails.
Escape Trajectories in Angelfish (Pterophyllum Eimekei)
Authors: Domenici Paolo , Blake Robert W. 
Published: April 2021

ABSTRACT
Although fish escape trajectories are linearly related to stimulus direction, they vary considerably after the initial turn away from the stimulus. Past studies of escape trajectories in fish and other animals have been analysed by employing linear plots of stimulus angle versus body turning angle. Here, we define escape trajectories as a circular variable, with 0° as stimulus direction.
Angelfish (Pterophyllum eimekei) escape in non-random trajectories when the stimulus is presented laterally, within an angular zone of approximately 30–120° (discriminating zone). The circular plot of escape trajectories shows a bimodal pattern that cannot be revealed by linear analysis. Angelfish escape preferentially at 180° and 130° away from the stimulus, maximizing the distance covered from the stimulus and escaping at the limit of their discriminating zone, respectively. Angelfish correct their responses when turning towards the stimulus, suggesting that escape trajectories are modulated by sensory feedback.
Re-analysis of published work on other animals, by employing circular histograms of escape trajectories, reveals multimodal patterns which are also not apparent from the linear plots. We suggest that the presence of multiple preferred trajectories may be adaptive in preventing predators from learning any single fixed pattern of response and compensating for it.
The relationship between intracellular pH and seasonal temperature in the brown trout Salmo trutta
Authors: Butler P. J. , Day N. 
Published: April 2021

ABSTRACT
Early studies on reptiles demonstrated that plasma pH increases as body temperature falls (Robin, 1962). Rahn (1967) proposed that plasma pH in all poikilothermic vertebrates is regulated as body temperature changes so as to maintain a constant relative alkalinity, i.e. a constant [OH−]/[H+] ratio, and Reeves (1972) suggested a way in which this could be achieved. Known as the ‘imidazole alphastat hypothesis’, it postulates that is regulated (by way of ventilation) so that the fractional dissociation (α) of the imidazole moiety of histidine is kept constant. As the pK′−of imidazole changes with temperature in about the same manner as the neutral pH of water (Heisler, 1986), the alphastat hypothesis is consistent with that of constant relative alkalinity.
Epinephrine Stimulation of Glucose Release From Perfused Trout Liver: Effects of Assay and Acclimation Temperature
Authors: McKinley Susan J. , Hazel Jeffrey R. 
Published: April 2021

ABSTRACT
Since fish are poikilothermic, changes in temperature may perturb hormonal activation of cell function. To test this hypothesis, and determine the extent to which hormonal responses are thermally compensated, the effect of temperature on epinephrine-stimulated glucose release in perfused trout liver was studied. Thermally acclimated (5 and 20°C) rainbow trout (Oncorhynchus mykiss) were responsive to epinephrine (0.5×10−6 mol l−1) at both 5 and 20°C. Metoprolol (β2 antagonist) and propranolol (α1and2) decreased the response significantly (to 1.4% and 8.4% of stimulated values, respectively) while phentolamine (α1and2) was without effect, implying the response is β2-mediated. Both basal (86 and 19μ,mol g−1 liver h−1 in 5 and 20°C trout, respectively) and epinephrine-stimulated (210 and 168 μ,molg−1 h−1) rates of glucose release were higher (2.4-fold higher for epinephrine-stimulated and 8.8-fold for basal) in 5°C-than in 20°C-acclimated fish, regardless of perfusion temperature. Although the dose–response curve for epinephrine was markedly temperature-dependent, cold-and warm-acclimated fish were affected in different ways. Cold-acclimated fish (5°C) were less responsive to epinephrine when perfused at 5°C (ED50 6.8×10−9 mol l−1) than when perfused at 20°C (ED50 8.2×10−10 mol l−1); in contrast, warm-acclimated fish (20°C) were less responsive to epinephrine when perfused at 20°C (ED50 4.6×10−7 mol l−1) than at 5°C (ED50 6.6×10−9 mol l−1). These results are interpreted as being indicative of adaptations to maintain the capacity for hepatic glucose mobilization at low temperature.
Ontogenetic Scaling of Jump Performance in the African Desert Locust (Schistocerca Gregaria)
Authors: Katz Stephen L. , Gosline John M. 
Published: April 2021

ABSTRACT
Ontogenetic growth was used as a model for the effect of body size on jumping performance of the African desert locust (Schistocerca gregaria). Using models that generated relationships between morphology and body size proposed by McMahon and the relationships between morphology and performance described by Hill, we generated testable predictions of how jumping performance measures may change as a function of body mass. Data were collected over an ontogenetic sequence that ranged from 1-day-old first instars to 45-day-old adults. Performance was quantified using a high-sensitivity, three-dimensional force plate. Performance parameters quantified included the force, acceleration, take-off velocity, kinetic energy and power output. With the exception of power output, each measure of performance scaled to body mass in a manner consistent with the predictions of the elastic similarity model. Power output scaled to body mass in a manner consistent with the predictions of the constant stress similarity model. As we noted previously for the scaling of flexural stiffness of the metathoracic tibiae, the elastic similarity model is approximated by the performance of the locust in spite of the morphological design that deviates from that model’s predictions.
These results indicate that the jump has separate functions in the flightless juvenile instars and in the flying adult stage of the life history. Juvenile locusts produce take-off velocities of between 0.9 and 1.2 ms−1 that are relatively scale-independent. The take-off velocity in juveniles produces a distance of ballistic travel that averages between 20 and 30cm. In adults, the take-off velocity is also relatively scale-independent at a level approximately twice as high as in juveniles (i.e. 2.5 ms−1). This velocity is coincident with the minimum flight speed reported by Weis-Fogh and a minimum flight speed that we have estimated using actuator disc theory. We suggest that, in juveniles, the jump is designed to achieve a characteristic distance travelled and in adults the jump is designed to achieve a minimum velocity necessary to fly.
Neuronal Feedback In Egg-Laying Behaviour of the Pond Snail Lymnaea Stagnalis
Authors: Ferguson Graham P. , Pieneman Anton W. , Jansen Rene F. , Maat Andries Ter 
Published: April 2021

ABSTRACT
The egg-laying behaviour of gastropod molluscs is controlled by peptidergic neuroendocrine cells and has provided an important experimental system for behavioural neurobiology. The genes that code for multiple peptides have been sequenced and the peptides themselves have been identified, thus enabling us to investigate how they act on the nervous system to produce the overt behavioural pattern (reviewed by Geraerts et al. 1988). The two animals that have been studied most extensively are the opisthobranch Aplysia californica and the pulmonate Lymnaea stagnalis. In both cases, the peptidergic neurones controlling egg laying are normally electrically silent (both in vivo and in vitro; Kupfermann, 1967; Pinsker and Dudek, 1977; Kits, 1980; Ter Maat et al. 1986) and produce multiple peptides (Rothman et al. 1983; Geraerts et al. 1985; Sigvardt et al. 1986), which are cleaved from a common protein precursor (Scheller et al. 1983; Vreugdenhil et al. 1988). Before egg laying, the cells produce a long-lasting discharge of action potentials (Pinsker and Dudek, 1977; Ter Maat et al. 1986). This electrical discharge initiates egg-laying behaviour, and during it the peptides (one of which initiates ovulation) are released into the blood. The demonstration, in Aplysia californica, that these peptides could have various effects on the activity of central neurones (reviewed by Mayeri and Rothman, 1985) led to the hypothesis that egg-laying behaviour is a neuroendocrine fixed action pattern controlled and coordinated by the concerted actions of the released peptides (Scheller and Axel, 1984). This hypothesis is also thought to apply to Lymnaea stagnalis (Vreugdenhil et al. 1988) because of the structural similarities between precursors of Aplysia californica and Lymnaea stagnalis egg-laying hormones. In this paper we investigate how the sequence of the various components of the egg-laying behaviour pattern is achieved.
Isolation of Epidermal Cell Pairs from an Insect, Tenebrio Molitor, For Dual Whole-Cell Recording of Large-Conductance Gap-Junctional Channels
Authors: Churchill Dennis , Caveney Stanley 
Published: April 2021

ABSTRACT
The segmented insect integument, composed of an epidermal monolayer and its cuticular secretion, is a paradigm for the study of pattern formation during development (Lawrence, 1992). Epidermal activity during development may be coordinated by the transfer of cytoplasmic molecules through cell–cell gap-junctional channels (reviewed in Caveney, 1985). Gap junctions within intact epidermal segments exhibit dynamic changes in their permeability properties during the moult cycle in vivo (Caveney, 1978) and with exposure to the developmental hormone 20-hydroxyecdysone in vitro (Caveney and Blennerhassett, 1980). In addition, the row of epidermal cells at segment borders has distinct permeability properties creating developmental and communication compartments (Warner and Lawrence, 1982; Blennerhassett and Caveney, 1984). This paper documents a method for isolating epidermal cells that are suitable for dual whole-cell voltage-clamp studies of gap-junctional currents. We have identified a large-conductance gap-junctional channel in cell pairs with octanol-reduced junctional currents. This cell model may be useful for examining mechanisms of gap-junctional channel gating during development.
Use of Tc-99m-pertechnetate to follow liquid water uptake by Porcellio scaber
Authors: Drobne D. , Fajgelj A. 
Published: April 2021

ABSTRACT
Terrestrial isopods are, apart from the amphipods, the only group of crustaceans living on land. They have evolved some functional and anatomical adaptations to manage water and ion exchange between themselves and their environment, and these are different from those in all other crustaceans. In higher terrestrial isopods, liquid water is taken in by mouth (Hoese, 1981) and water vapour is absorbed in the pleoventral space (Wright and Machin, 1990; Wright and O’Donnell, 1992). Spencer and Edney (1954) also showed that water from wet filter paper can be taken up by the animals’ rear appendages (uropods).
Retinals and Retinols Induced By Estrogen in the Blood Plasma of Xenopus Laevis
Authors: Azuma Masami , Irie Toshiaki , Seki Takaharu 
Published: April 2021

ABSTRACT
Injection of estrogen into male Xenopus laevis induced the appearance of retinals (retinal and 3-dehydroretinal) and a considerable increase in the amount of retinols (retinol and 3-dehydroretinol) in the blood plasma. These retinoids were mainly in the all-trans form. Without estrogen injection, retinols were normally found in the blood plasma of both males and females, but only trace amounts of retinals were detected and these were restricted to the plasma of females.
The proteins in the blood plasma of estrogen-injected males were separated into two fractions. One fraction included vitellogenin, the precursor of egg yolk proteins, and the other contained some plasma proteins other than vitellogenin. Retinals were detected in the former and retinols in the latter. It is suggested that retinals are bound to vitellogenin and are taken up into oocytes in the process of vitellogenesis.
Ovulation and Oviposition in Anura
Authors: Waring H. , Landgrebe F. W. , Neill R. M. 
Published: April 2021

ABSTRACT
The normal rhythm of sexual activity of both Xenopus and Rana is controlled by secretions of the anterior lobe pituitary. Progesterone and testosterone, as well as extracts of A.L.P., evoke ovulation in normal and hypophysectomized Xenopus. Injection of pregnancy urine into hypophysectomized Xenopus evokes enlargement of the reduced ovary and ovulation. Serial injections of pituitary extracts and oestrin were without effect on the amount of egg jelly secreted. Ovulation in Xenopus is immediately followed by oviposition. The eggs are carried by continuous ciliary tracts from the body cavity via the oviduct to the exterior. In Rana ovulation is not immediately followed by oviposition. The eggs accumulate in the lower third of the oviduct and are expelled en masse. Experiments on extirpation of endocrines and the injection of appropriate extracts, together with the responses to pithing and electrical stimulation, lead to the conclusion that oviposition in Rana is probably under nervous not humoral control. The muscular and skeletal mechanism involved in the retention and extrusion of eggs in Rana is described.
On Chromatic Effector Speed in Xenopus and Anguilla and the Level of Melanophore Expanding Hormone in Eel Blood
Authors: Waring H. , Landgrebe F. W. 
Published: April 2021

ABSTRACT
Hogben and his co-workers (Hogben & Slome, 1931, 1936; Neill, 1940) have drawn conclusions from the time relations of the responses of intact Xenopus and eels which presuppose that the limiting factor in the slow responses is the equilibration of the co-ordinating pituitary hormones in the blood and is not due to the inertia of the melanophores. The present investigation has shown that this supposition is justified. The chromatic effector speed of the two species has been measured by perfusing fully dark animals with saline until they were fully pale and then introducing B hormone into the perfusate to observe the reverse change. It was found that:(a) Complete expansion of the melanophores of Xenopus takes too min. Complete contraction of the melanophores of Xenopus takes 70 min.(b) Complete expansion of the melanophores of the eel takes 30 min. Complete contraction of the melanophores of the eel takes 20 min.Adrenalin exercises a potent contracting effect on the melanophores of the eel even in the presence of excess B. It has no direct effect on the melanophores of Xenopus.Increased concentration of B hormone in the perfusate above the threshold dose does not increase the speed of melanophore expansion in either animal. This implies something approaching an all or nothing reaction on the part of the melanophore itself. The usual interpretation of the “all or nothing” behaviour of effectors is that it is in large measure due to the well-known “all or nothing” action of their efferent nerves.Using eels of approximately the same weight estimations of:(a) concentration of B hormone in the circulation of a dark fish,(b) concentration of B hormone in the pituitary of a dark fish,(c) total blood volume, indicate that the distribution of B between pituitary and circulation in a dark animal is of the order pituitary 1, circulation 10.Caustic soda treated extracts of posterior lobe pituitary which evoke the same rise of melanophore index as untreated extracts do not maintain the expanded condition of the melanophores for the same period. The factors involved are discussed.
The Mechanisms of Humidity Reactions of Terrestrial Isopods
Authors: Waloff Nadejda 
Published: April 2021

ABSTRACT
The humidity reactions of Oniscus asellus, Porcellio scaber and Armadillidium vulgare have been analysed and compared. The mechanism whereby the three species collect in moist air is twofold, Consisting of (a) hygrokinesis, or decrease in activity and speed in moist air, and (b) of more frequent turnings in space, retaining them in the areas of greater humidity. These mechanisms are most clearly expressed in Oniscus asellus and least in Armadillidium vulgare. This sequence may be correlated with the resistance to desiccation of the three species, which is greatest in Armadillidium vulgare, and greater in Porcellio scaber than in Oniscus asellus. It is suggested that the humidity reactions of isopods are controlled by water loss by evaporation from the whole body. A correlation between hygrokinesis and thigmokinesis was observed in Porcellio scaber. There appears to be a reversal from negative to positive phototaxis in Oniscus asellus, correlated with the water loss by evaporation. The humidity reactions, low thigmokinesis and negative phototaxis combine to retain the isopods in damp, dark habitats.