bluuebunny/crossref_metadata_2025 huggingface dataset:
The Chemical Composition of Lipid Globules in the Neurones of Helix aspersa
Authors: Chou J. T. Y.
Published: April 2021

1. The three kinds of globules that can be recognized in the living neurone of Helix aspersa are sharply distinguishable from one another by histochemical tests.

2. One kind of globule contains phospholipid; another appears to consist of triglyceride ; the third is complex chemically, containing mixed lipids with some protein and carbohydrate.

3. When osmium techniques for the ‘Golgi apparatus’ are applied to this particular cell, phospholipid is blackened.
Cytoplasmic Inclusions of the Neurones of Gastropods
Authors: Malhotra S. K.
Published: April 2021

The neurones of the sub-oesophageal ganglionic mass of the Simla slug, Anadenus altivagus, and the Bharwain snail, Euaustenia cassida, have been investigated by phasecontrast microscopy of the living cells and in fixed preparations. The mitochondria are seen as granules and filaments in both living and fixed material. Alignment of granules into filamentous mitochondria has also been observed in the fixed preparations. The lipid spheroids (corresponding to the ‘binary spheroids’ of Thomas and the ‘lipo-chondria’ of Roque) are sudanophil, osmiophil, and argentophil. The bigger spheroids show a duplex structure, consisting of a cortical, chromophil, lipid component, which may be in the form of a complete ring (Anadenus) or in the form of one or two granules or a crescent (Anadenus and Euaustenia), and a chromophobe medulla (neutral red vacuome of Parat), in which lipochrome develops to form the ‘mulberry spheroids’ of Thomas. The small homogeneous lipid spheroids also contribute to the formation of ‘mulberry spheroids’.
A Note on the Opacity to X-Rays of Tissues fixed with Mercuric Chloride
Authors: Foxon G. E. H.
Published: April 2021

The radiography of ‘soft’ tissues normally requires special X-ray apparatus which generates soft X-rays. Fixation with mercuric chloride, either alone or in mixture, has been found to render such ‘soft’ tissues opaque to those harder X-rays generated by normal clinical X-ray apparatus. Radiographs made by the use of such standard apparatus may be useful in several fields of biological research such as anatomical investigation and illustration, or in the study of the penetration and behaviour of the fixatives themselves.
The Growth of Mixed Populations of Chilomonas paramecium and Tetrahymena patula
Authors: Mučibabić Smilja
Published: April 2021

In mixed cultures, where Tetrahymena patula preys on Chilomonas paramecium, the growth of the Chilomonas population does not initially differ significantly from that in single cultures. Later, however, the decrease in numbers of Chilomonas is more rapid in mixed cultures, where it dies out after two months.

The composition of the polymorphic Tetrahymena patula population depends on age and on the presence or absence of Chilomonas. Slitmouthed forms are absent at the beginning of growth in both mixed and single cultures, and only appear subsequently in mixed cultures. The percentage of these forms increases in older cultures. The percentage of microstomatous forms is larger, however, at the beginning of population growth, both in mixed and single cultures. The percentage of macrosto-matous forms increases from the beginning, reaches a maximum, and then decreases. Cannibalism has been observed in old mixed cultures.

Significant differences in the size of individual organisms of Chilomonas between single and mixed cultures appeared from the beginning of the logarithmic phase of growth, and were pronounced up to the end of observations. Significant differences in the size of Tetrahymena patula between single and mixed cultures appeared somewhat later, from the sixth day onwards.

The differences in size and shape between organisms in cultures of the same kind but of different ages were also significant. Variation in size and shape of both species was greater in mixed than in single cultures.
Histochemical Studies of Lipids in Oocytes
Authors: GURAYA SARDUL SINGH
Published: April 2021

Judging from their sizes and histochemical reactions, three types of lipid bodies in the form of granules and spheres have been observed in the early stages of oogenesis. The minute granules (L1), belonging to the first type appear to consist of phospholipids, triglycerides, and fatty acids, but the presence of proteins cannot be ruled out. They correspond to the so-called granular mitochondria of other authors of papers on the oogenesis of birds. The second type of lipids (L2) are of medium size and they contain phospholipids and a certain amount of triglycerides. They resemble the socalled ‘Golgi bodies’ of earlier authors in appearance and react like them with osmium tetroxide and silver nitrate. They seem to originate from the granules of the first category (L1). The third type of lipids (L3) are the AH-negative spheres consisting of triglycerides and cholesterol and its esters. They correspond to the ‘fatty yolk’ of earlier authors. Their origin appears to be from the second type of lipid bodies (L2), as intermediate bodies (int) of varying chemical composition between the L2 and L3 have been observed. The ‘peripheral lipid bodies’ (pl) found in association with vacuoles are larger than the second type of AH-positive bodies (L2), but they seem to contain different types of phospholipids, triglycerides, and some other substances also. Besides these lipid bodies, a mass of lipoprotein bodies has also been observed. At the time of their origin, the yolk globules of the advanced oocytes do not contain lipids but later on they develop triglycerides and phospholipids. The lipid bodies of the follicular cells correspond very closely to the first two categories of sudanophil AH-positive bodies (L1 and L2) of the oocyte proper.
A Bleaching Method for Melanin and two Staining Methods
Authors: Chesterman W. , Leach E. H.
Published: April 2021

An acidified permanganate method can be used for bleaching melanin in mammalian skin and eyes. It allows good staining to be performed later.

Microfilariae in nitrocellulose sections can be stained by a modified phloxine tartrazine method.

Elastic fibres can be selectively stained by using a diluted solution of synthetic orcein.
The Vascular System of Crustacean Compound Eyes, especially those of the Euphausid, Meganyctiphanes norvegica
Authors: Mauchline J.
Published: April 2021

When the compound eyes of Meganyctiphanes and a number of decapods were examined a constant general pattern of blood-vessels was found.

The optic artery produced a branch to each of the following: the medulla terminalis, medulla interna, medulla externa, lamina ganglionaris, and the subretinal region. It then terminated in the dorsal region of the eye, passing the remaining blood into the ommatidial sinus.

The blood from the ommatidial sinus and from the systems of fine vessels in the nerve ganglia and subretinal region flows into the eye-stalk sinuses, whence it reaches the cephalothoracic sinuses.
The Utilization of I131 by Certain Lamellibranchs, with Particular Reference to Shell Secretion
Authors: Beedham G. E. , Trueman E. R.
Published: April 2021

A study of the utilization of I131 by the lamellibranchs Anodonta cygnea, Sphaerium comeum, and Mytilus edulis has been made with particular reference to the secretion of the valves and ligament.

While autoradiographs show that I131 is localized in the alimentary canal and digestive gland, the main distribution of the isotope is on the surfaces of the shell and body exposed to the radioactive medium. The iodine associated with the shell occurs principally on the periostracum. There is, however, no positive evidence to show that I131 is actively incorporated into the shell by the secretory activity of the mantle. The results are discussed in relation to the ability of other invertebrates to accumulate protein-bound iodine.
The Action of Colchicine on the Intestinal Epithelium of the Cat and Dog
Authors: Mcminn R. M. H.
Published: April 2021

Varying doses of colchicine have been administered intraperitoneally to cats and dogs in order to study histologically the reactions in the epithelium of the small intestine. In normal animals of both species, approximately 1 % of the total number of epithelial cells in the ileum are in mitosis at a given time. After exposure to colchicine for 5 h, the maximum number of arrested mitoses in the cat was found to be 3—77%; in the dog the maximum number rose to 17—12%. The results indicate that in the epithelial cells of the dog’s small intestine, colchicine not only arrests mitosis in meta-phase, but also stimulates the cells to enter mitosis.
A Study of the Muscular Anatomy and Swimming Behaviour of the Sea Anemone, Stomphia coccinea
Authors: Sund Paul N.
Published: April 2021

The sea anemone Stomphia coccinea, when touched by certain starfishes, frees itself from the substratum, and by a series of waving motions propels itself through the water. This locomotion has been studied by means of direct observation and by analysis of time-lapse, and normal-speed motion-picture films.

Ecological observations and stimulation tests made in the natural environment of the anemone are described and discussed.

The musculature of the anemone is described, and the function of the various muscles is discussed with regard to their participation in swimming. The muscles that play the most important part in the animal’s movement through the water are the parieto-basilar and the circular muscle-sheet. The other muscles are involved in the overall reaction, but act only as aids in maintenance of the form of the anemone during actual swimming.

Experiments involving the ability of several species of starfish to elicit swimming are described. It has been established that, of those asteroids tested, only Dermasterias imbricata and Hippasteria spinosa are consistently effective in causing Stomphia to swim.

The possibility that swimming serves as a means of escape from starfish predators is considered. Observations and simple experiments indicate that predation may not be a factor in this relationship between starfishes and the anemone.

Observations of the anemones in their natural environment suggested that swimming might be a means to remove debris settling on the oral disk and eventually burying the animal. Experimentally, this could not be substantiated; silt is removed by the cilia of the oral end of the anemone.

That the starfish release some chemical which serves as a stimulant to the anemone is considered; but experiments indicate that if such a substance is present it probably is not water-soluble.

It was discovered that swimming could be brought about by electrical stimulation. The response is facilitated and can be controlled, to a certain degree, by giving stimuli of proper intensity and frequency for varying periods of time (e.g. 6 volts at 1-sec intervals over a period of 2 to 8 sec).

Possible uses for the swimming reaction in nature are considered, but this question still remains open to further speculation and experimentation.
Unmasking of Sudanophil Lipid in the Testis of the House-cricket, Acheta domesticus
Authors: Clayton Blanche-P.
Published: April 2021

1. When the testis of Acheta domesticus is fixed in Flemming’s fluid and embedded in gelatine, Sudan black reveals scarcely any lipid in the externum of the acroblast.

2. It can be shown that the externum of the acroblast contains much lipid in a masked (bound) form.

3. Experiments were performed to find what substances were effective, after Flemming fixation, in unmasking the lipid of the externum and thus making it colourable by Sudan black.

4. The following substances were found to act as unmasking agents: ethanol, dioxane, phenol, resorcinol, hydroquinone, pyrogallol, tannic acid.

5. Under the conditions of the experiment, the most effective unmasking agents were 90% ethanol and 5% hydroquinone.
Histochemical and Morphological Studies of Lipids in the Oogenesis of Pheretima posthuma
Authors: Nath Vishwa , Gupta Brij L. , Manocha S. L.
Published: April 2021

A study of the oocytes of the earthworm, Pheretima posthuma, examined fresh under the phase-contrast and interference microscopes as well as by histochemical techniques, has revealed that there are two types of lipid bodies in the cytoplasm. The lipid bodies of the first type (L1) are smaller, appear as homogeneous, dark granules under the phase-contrast microscope, and have a protein-phospholipid core surrounded by a thick sheath of phospholipids only. The lipid bodies of the second category (L2), which arise as a result of growth and chemical change in L1 bodies, have a pure phospholipid core surrounded by a thick triglyceride sheath. They give a ringed appearance under the phase-contrast microscope. The study under the interference microscope shows that this ringed appearance is an optical artifact. The lipid spheres present in the follicular epithelium contain phospholipids only.

The mitochondria are in the form of minute granules. They remain unchanged throughout oogenesis.

Some vacuoles devoid of any lipids, proteins, or carbohydrates have been observed. They also remain unchanged.

Pure triglyceride spheres, yolk globules, nucleolar extrusions, as well as cholesterols and cholesteryl esters are absent.
The Fine Structure of the Mesenteries of the Sea-Anemone Metridium senile
Authors: Grimstone A. V. , Horne R. W. , Pantin C. F. A. , Robson Elaine A.
Published: April 2021

Sections of the retractor and radial face of mesenteries of Metridium senile (L.) fixed withosmic, osmic-phosphotungstic, or formol-phosphotungstic fixatives were examined by electron microscopy. Each muscle-fibre forms the basal part of a musculo-epithelial cell and is in contact through the cell membrane with a differentiated surface layer of the underlying mesogloea. The muscle-fibres bear crests of cytoplasm containing mitochondria. Each crest is continuous with a cytoplasmic stem which passes through the intercellular space into the epithelial part of the musculo-epithelial cell. The musclefibre consists of densely packed longitudinal filaments 40-80 Å across. The musclefibres present a similar appearance over a great range of extension of the muscle. The filaments show no gross periodic structure like that of striated muscle; nor has any fine regular structure like that described in some other ‘plain’ muscle-fibres yet been detected. There is, however, an irregular beading on the filaments at about 240 Å. Though much smaller, the muscle-fibres of the very slowly contracting radial muscle sheet have the same fine structure as those of the very rapidly contracting retractor muscle. The epithelial part of the cell bears a flagellum arising from a cytoplasmic ‘crater’. The flagellum contains vesicles as well as the typical fibrils. It passes continuously into a complex basal corpuscle which continues into a striated fibrous root. Near the epithelial surface there are conspicuous cross-connexions between adjacent cells. Mucus cells and amoebocytes are described. The mesogloeal lattice of Chapman, which permits free extension of the actinian body, is composed of fibres which seem to be built up of tubular fibrils of about 100 Å diameter. The fibrils show well-developed banding at 260 Å. Where fibrils adhere together their banding is congruent. The criteria of correspondence between the electron micrographs and the living structure are discussed, and the value of information from artifacts and varied methods of fixation is noted.
Studies in Animal Locomotion
Authors: Gray J.
Published: April 2021

The two previous papers in this series have dealt almost exclusively with the movements of fish, such as the eel or the butterfish (Centrono tus gunnellus) whose bodies are long and flexible and which exhibit very well-defined waves of muscular contraction when the fish are travelling through the water. The present paper deals primarily with pelagic fish which differ from the eel in two important respects; they possess well-developed caudal fins and the ratio of body lengthbody width is much smaller.
The Cuticular Stress Detector (Csd2) of the Crayfish I. Physiological Properties
Authors: Klärner Diemut , Barth Friedrich G.
Published: April 2021

The cuticular stress detector (CSD2) is coupled to a patch of compliant cuticle in the ischiopodite. It is excited when the compliant cuticle is deformed directly or by deformation of the surrounding stiffer cuticle. Sinusoidal force (1Hz) directly applied to the compliant cuticle revealed sensory units with thresholds as low as 0·03 mN. The thresholds of most units are higher by up to 40 dB. The stimulus-response curves of the CSD2 units in all preparations have an activity peak between 10 and 30 Hz. In some units (on-units) the spike frequency is high while the force on the cuticle increases. The activity of other units (off-units) declines with rising force. The phase relationship between stimulus and response and the magnitude of the response depend on the exact site of force application. The sensory units of CSD2 can supply the CNS with detailed information about the forces acting on the surrounding cuticle.
The Morphology and Physiological Properties of the Small White Neurones in the Buccal Ganglia of Tritonia Hombergi
Authors: Dorsett D. A.
Published: April 2021

The two small white (W) cells in the buccal ganglia of Tritonia hombergi can initiate and modulate cyclic activity in the pattern generating neurones which drive feeding activity in the buccal mass.

They also make extensive monosynaptic connections with the buccal moto-neurones, generating EPSPs on protractor (P) cells, IPSPs on retractor (R) cells, and EIPSPs on the small radula flattener (F) cells. Two F motoneurones receive a chemically mediated, facilitating EPSP from the W cells.

Inactive W cells receive weak excitatory feedback from the pattern generating network interneurones (FPG) in phase I of the feeding cycle and also from some F cells. Prolonged depolarization of one W cell recruits the other. When both are active they adopt a patterned burst mode with a common inhibitory input in phase I.
Synaptic Basis of Swim Initiation in the Leech: III. Synaptic Effects of Serotonin-Containing Interneurones (Cells 21 and 61) on Swim Cpg Neurones (Cells 18 and 208)
Authors: Nusbaum Michael P.
Published: April 2021

Serotonin-containing cells 21 and 61 strongly excite a swim central pattern generator (CPG) neurone, cell 208, in nearby segmental ganglia in the leech Macrobdella decora. This excitatory effect is apparently independent of activity in the swim-initiating neurone cell 204, which monosynaptically excites cell 208 (Weeks, 1982b). Cell 208 excites cell 21, apparently directly. This is the first identified direct pathway for feedback from the swim central pattern generator to a swim initiator neurone. Focally applied serotonin has no effect on the soma of cell 208, but causes both excitatory and inhibitory responses in cell 208 when applied to different places within the neuropile. Cell 61 polysynaptically excites distant, posterior cells 208. This excitation is mediated at least in part by the activation of nearby cells 208, which polysynaptically excite posterior cells 208. Cell 208 is dye-coupled intraganglionically to a newly identified pair of neurones, designated cells 18. Cell 208 also excites posterior cells 18, apparently directly. This interaction may be the pathway whereby cell 61 polysynaptically excites posterior cells 208. During swimming, cell 18’s membrane potential oscillates in phase with cell 208. Intracellular current injection into cell 18 during swimming perturbs the swim motor pattern. Therefore, cell 18 qualifies as a candidate swim CPG neurone.
Recovery From Anaerobiosis in the Intertidal Worm Sipunculus Nudus II. Gas Exchange And Changes in the Intra- And Extracellular Acid-Base Status
Authors: Pörtner H. O. , Vogeler S. , Grieshaber M. K.
Published: April 2021

Intra- and extracellular acid-base status and changes of coelomic were investigated during recovery following 24 h of anaerobiosis in Sipunculus nudus L. Metabolism, gas exchange and acid-base status were compared in animals collected during March and October.

Anaerobiosis led to an uncompensated metabolic acidosis, the degree of the acidosis depending on the metabolic rate of the animals. During initial recovery in March animals, the acidosis was transiently aggravated in the extracellular, but not in the intracellular, compartment, indicating an efficient regulation of intracellular pH as soon as oxygen was available in the coelomic fluid. The extracellular acidosis was predominantly of non-respiratory origin.

The non-respiratory part of the acidosis is attributed to the repletion of the phospho-L-arginine pool. The proton yield calculated from phosphagen resynthesis was highly correlated in time and in quantity to the observed negative base excess in the extracellular compartment. In October animals, strombine accumulation may have contributed to the acidosis that develops during recovery. The amount of succinate, propionate, and acetate in the coelomic plasma had already decreased when the acidosis developed. This discrepancy supports the conclusion that protons move between the body compartments independent of the distribution of anionic metabolites.

The respiratory part of the acidosis is attributed to the repayment of an oxygen debt. The increase of is higher in October than in March animals, probably because of differences in metabolic rate.

The time course of acid-base disturbances and their compensation is discussed in relation to the time course of metabolic events during recovery and to the priorities of the different processes observed.
The Role of a Zinc-Based, Serum-Borne Sulphide-Binding Component in the Uptake and Transport of Dissolved Sulphide by the Chemoautotrophic Symbiont-Containing Clam Calyptogena Elongata
Authors: Childress J. J. , Fisher C. R. , Favuzzi J. A. , Arp A. J. , Oros D. R.
Published: April 2021

Calyptogena elongata is a small (about 7cm maximum length) species of vesicomyid clam which lives at depths of 494–503m, near the sill depth, in the Santa Barbara Channel in mildly reducing muds at low ambient oxygen concentrations. This species has abundant autotrophic sulphur-oxidizing bacteria in bacteriocytes in its gills. The stable carbon isotope composition values of its gills and other tissues range from −36 to −38‰, supporting the suggestion that the primary carbon source for this symbiosis is inorganic carbon fixed by the endosymbionts. This species of clam concentrates sulphide into its blood serum by using a sulphide-binding component and into the gills by using an unknown sulphide-binding activity. In both tissues, total H2S concentrations within the clam can greatly exceed those outside. This apparently enables the clam to concentrate sufficient sulphide from the mildly reducing muds to support the needs of its endosymbionts. Both of these binding activities are reversible in vivo as shown by the rapid declines in blood and gill sulphide levels when the clams are deprived of sulphide and the rapid concentration of sulphide into the blood and gills when it is provided. For example, within minutes of exposure to 65 μmol l−1 H2S, gill and blood total H2S concentrations in individual C. elongata exceed the external concentration; within 2 h they reach maximum concentrations of about 2mmol l−1. When such experiments are carried out under anoxic conditions, the blood and gill total H2S concentrations approach saturation (10–20mmol l−1), indicating that under oxic conditions the oxidation of sulphide by the clam and its endosymbionts holds the binding components below saturation and enables them to protect the animal tissues and endosymbionts from toxic concentrations of sulphide. In contrast to these results for C. elongata, our experiments show that the host of another chemoautotrophic symbiosis, Solemya reidi, does not concentrate sulphide from the medium into either its blood or its gills. Data are presented which indicate that the serum sulphide-binding component is a large molecular mass molecule with Zn2+ at the active site. This study strongly supports the model of vesicomyid functioning in which the blood-borne sulphide-binding component concentrates sulphide from the reducing environment around the clam’s foot and transports this sulphide to the symbionts in the gills. Data are also presented which indicate that the clam oxidizes some sulphide to thiosulphate and transports this to the gills as well. Thus, individual C. elongata, like the previously studied C. magnifica, appear to bridge the reducing and oxidizing zones of their habitats to provide needed substrates to their endosymbionts. Examination of these two species and the anatomy of other vesicomyid species suggest that vesicomyid clams are functionally quite conservative.
An Analysis of Control of the Ventricle of the Mollusc Mercenaria Mercenaria: I. The Ionic Basis of Autorhythmicity
Authors: Devlin C. Leah
Published: April 2021

During spontaneous beating (autorhythmicity) in the bivalve ventricle, the cardiac action potential (AP) was generated by calcium (Ca2+) and sodium (Na+) influx. The initial fast rising phase (the ‘spike’) of the cardiac AP was dependent on extracellular Ca2+ concentration, whereas the slow plateau phase was Na+-dependent.

The initial fast rising phase of the cardiac AP was abolished by treatment with a Ca2+-free saline or inorganic Ca2+ entry blockers, such as lanthanum chloride or cobalt. Conversely, this fast rising phase of the AP was potentiated by treatment with barium ions, the dihydropyridine-sensitive Ca2+ channel agonist Bay K 8644 or, unexpectedly, by the organic Ca2+ entry blocker diltiazem.

The force of systolic beating was directly proportional to the amplitude of the fast rising phase of the cardiac AP. The Ca2+-dependent, fast rising phase of the AP was modulated by the level of extracellular Na+. Both the amplitude of the fast rising phase of the AP and coupled systolic force were increased by progressive reduction of extracellular Na+ concentration.

The slow plateau phase was abolished by treatment with a Na+-free saline and potentiated by the Na+ ionophore monensin. The size of the Na+-dependent plateau was modulated by the level of extracellular Ca2+. When extracellular Ca2+ was removed from the bathing saline, both the amplitude and duration of the plateau phase were increased. Conversely, restoring extracellular Ca2+ to physiological levels decreased the size of the Na+-dependent plateau.

Autorhythmicity was dependent on the level of extracellular potassium. In the absence of K+, neither a Ca2+-dependent fast rising phase nor a Na+-dependent plateau phase was recorded.
Animal Flight Mechanics in Physically Variable Gas Mixtures
Authors: Dudley Robert , Chai Peng
Published: April 2021

Empirical studies of animal flight performance have generally been implemented within the contemporary atmosphere. Experimental alteration of the physical composition of gas mixtures, however, permits construction of novel flight media and the non-invasive manipulation of flight biomechanics. For example, replacement of atmospheric nitrogen with various noble gases results in a tenfold variation in air density at a constant oxygen concentration. Such variation in air density correspondingly elicits extraordinary biomechanical effort from flying animals; hummingbirds and euglossine orchid bees hovering in such low-density but normoxic mixtures have demonstrated exceptionally high values for the mechanical power output of aerobic flight muscle. As with mechanical power, lift coefficients during hovering increase at low air densities in spite of a concomitant decline in the Reynolds number of the wings. The physical effects of variable gas density may also be manifest in morphological and physiological adaptations of animals to flight across altitudinal gradients. Global variation in atmospheric composition during the late Paleozoic may also have influenced the initial evolution and subsequent diversification of ancestral pterygotes. For the present-day experimenter, the use of physically variable flight media represents a versatile opportunity to explore the range of kinematic and aerodynamic modulation available to flying animals.
Three Neural Groups in the Femoral Chordotonal Organ of the Cricket Gryllus Bimaculatus: Central Projections and Soma Arrangement and Displacement During Joint Flexion
Authors: Nishino Hiroshi , Sakai Masaki
Published: April 2021

The arrangement of neuronal somata and their displacement during joint flexion together with the central projection of the pro- and metathoracic femoral chordotonal organs (FCOs) in the cricket were investigated. The FCO consists of the partially fused ventral and dorsal scoloparia in the proximal femur. The ventrally located neurones (the ventral group) form chain-like rows in which somata became sequentially smaller distally and project their axons ipsilaterally to the dorso-lateral regions, giving off abundant branches and terminating in the region between the dorsal intermediate tract and the ventral intermediate tract in the thoracic hemiganglion. The dorsal scoloparium, composed of small, simply aggregated neurones, projects exclusively to the medioventral association centre (mVAC), which is known to be an auditory neuropile. In addition, another neural cluster (the dorsal group) was found in the proximo-dorsal region of the ventral scoloparium. This was composed of simply aggregated neurones with axons giving off sparse branches dorso-laterally and terminating in the peripheral region inside the mVAC. The somata of these three groups were displaced distally by flexion of the femoro-tibial joint: the ventral group showed the greatest displacement, with the degree of movement depending upon soma location, while the dorsal group and dorsal scoloparium neurones were hardly displaced, possibly because of their strong connection with the cuticle. These properties were similar in both the prothoracic FCO and the metathoracic FCO. Taken together, the above points suggest that there is greater functional differentiation of the FCO than was previously thought.
Cyclic Amp Induces A Relaxation Response In The Bullfrog Rana Catesbeiana, But Nitric Oxide Does Not
Authors: Kline L. W. , Zhang M. L. , Pang P. K. T.
Published: April 2021

Cholecystokinin octapeptide (CCK), acetylcholine (ACh) and ceruletide have been shown to produce contraction in bullfrog (Rana catesbeiana) gallbladder strips. Agents capable of relaxing the bullfrog gallbladder are less numerous. Calcitonin gene-related peptide reduced the amount of both CCK- and ACh-induced tension in bullfrog gallbladder strips. The purpose of this study was to determine whether vasoactive intestinal peptide (VIP), nitric oxide (NO) and the second messengers cyclic GMP or cyclic AMP had any effect on gallbladder motility in the bullfrog. In vitro tension studies using L-NG-nitro-arginine methyl ester, Methylene Blue, sodium nitroprusside and N2,2′-O-dibutyryl guanosine 3′,5′-cyclic monophosphate suggested that nitric oxide did not modulate gallbladder motility in the bullfrog gallbladder. Histochemical staining for NADPH diaphorase (nitric oxide synthase) failed to demonstrate nerve fibers containing nitric oxide synthase in the bullfrog gallbladder. In vitro studies demonstrated that VIP had no effect on CCK-induced tension. However, in vitro studies using either 8-bromoadenosine 3′,5′-cyclic monophosphate or forskolin demonstrated that both agents relaxed strips precontracted with CCK. The results of this study suggested that, while neither NO nor VIP had a role in modulating bullfrog gallbladder motility, cyclic AMP was capable of modulating bullfrog gallbladder motility.
Is muscle involved in the mechanical adaptability of echinoderm mutable collagenous tissue?
Authors: Wilkie I. C.
Published: April 2021

The mutable collagenous tissue (MCT) of echinoderms has the capacity to change its mechanical properties in a time scale of less than 1 s to a few minutes under the influence of the nervous system. Although accumulating evidence indicates that the mechanical adaptability of MCT is due primarily to the modulation of interactions between components of the extracellular matrix, the presence of muscle in a few mutable collagenous structures has led some workers to suggest that contractile cells may play an important role in the phenomenon of variable tensility and to call for a re-evaluation of the whole MCT concept. This contribution summarises present information on MCT and appraises the argument implicating muscle in its unique mechanical behaviour. It is concluded that there is no evidence that the variability of the passive mechanical properties of any mutable collagenous structure is due to muscle.
The effect of stimulus features on the visual orienting behaviour of the salamanderPlethodon jordani
Authors: Schülert Niklas , Dicke Ursula
Published: April 2021

The effects of the visual features of prey-like objects on the orienting behaviour of the salamander Plethodon jordani were studied. Two stimuli (cricket dummies, rectangles), moving in opposite directions, were presented simultaneously on a computer screen. They differed in size, contrast, velocity and movement pattern of the entire body or the body appendages. Size and velocity appeared to be the dominant features; shape was of lesser importance. Contrast and movement pattern were of intermediate importance and local motion of little importance. This rank order was the same when the probability of a response to the different stimuli was estimated by means of the maximum-likelihood method. Cluster analysis revealed that in all animals stimuli could be grouped into five clusters. Among individuals, the rank order of stimuli was similar for high- and low-ranking stimuli and varied for those of intermediate rank; stimuli could be grouped into 3–5 clusters. Our findings favour the view that, in amphibians, prey recognition is guided by a number of visual features acting either alone or in combination and depending on internal motivational or attentional states and individual experience.

Movie available on-line: http://www.biologists.com/JEB/movies/jeb3864.html.
Whole-body hyperthermia-induced thermotolerance is associated with the induction of Heat Shock Protein 70 in mice
Authors: King Yueh-Tsu , Lin Chih-Sheng , Lin Jyh-Hung , Lee Wen-Chuan
Published: April 2021

Molecular mechanisms of whole-body thermotolerance (WBT) in mammals have not been investigated thoroughly. The purpose of this study was to assess the induction of the 70 kDa heat shock protein (HSP70) and antioxidant enzyme activity in animal WBT, which was induced by whole-body hyperthermia (WBH) in mice. As a preconditioning treatment, WBH was applied to mice to induce WBT. Synthesis of inducible HSP70 (HSP70i) and quantification of its increased level in liver were investigated by one- and two-dimensional polyacrylamide gel electrophoresis and immunoblotting. HSP70i synthesis in mice liver was induced by non-lethal WBH (41°C, 30 min). When compared to control animals, the level of liver HSP70i increased substantially (by 3.6-fold; P<0.0001). When exposed to 30 min of hyperthermia preconditioning, and after recovery for 48 h, the survival rate was 88.2 %, which was significantly higher than that of the control group (37.5 %; P<0.01). Moreover, the survival rate of animals subjected to preconditioning for 15 min was 72.2 %, which was also significantly higher than that of the control group (P<0.05). In contrast, the survival rate of animals subjected to preconditioning for 45 min was 63.5 %, which was not different from the control group. Nonetheless, the protection index of the group subjected to 15 min and 30 min of preconditioning was 1.93 and 2.37, respectively. Furthermore, to assess their contributions to WBT, the activities of antioxidant enzymes were also measured. After 48 h of recovery in preconditioned animals, hepatic antioxidant enzyme activities, including superoxide dismutase, catalase and glutathione peroxidase, had not changed significantly. To study the molecular mechanism of WBT, we successfully developed a mouse model and suggest that, rather than the activities of antioxidant enzymes, it is HSP70i that has a role to help animals survive during severe heat stress.
Osmoregulation in Some Freshwater Prawns
Authors: Parry Gwyneth
Published: April 2021

A freshwater prawn, Palaemonetes antennarius, from Italy, is shown to have a different level of salt concentration in the blood and urine compared with that of the brackish water P. varians and Palaemon longirostris in Britain. Although this prawn lives in fresh water the urine is isosmotic with the blood and is produced at a rate of about 2 % body weight/hr. An uptake of salts from a very dilute medium has been demonstrated in salt-depleted animals.
Motoneuron Responses to Visual Stimuli in Oncopeltus Fasciatus Dallas
Authors: Chapple William D.
Published: April 2021

Tonic discharges of homologous units in the left and right metathoracic leg nerves in response to increases and decreases in light intensity were observed. Periodic variations in the frequencies of these units was shown to be related to leg movement and at a frequency appropriate for walking. The intensity and duration of discharge of these units was related to the change in light intensity and the frequency of stimulation. The unit of one side normally fired at a higher frequency than that of the other. This was separate from the asymmetry produced by placing the animal in a rotating drum with a single 55° stripe. In this case, clockwise movement of the stripe produced a higher frequency discharge on the left side, while a counterclockwise movement reversed the frequency ratio. Units in the connectives appeared to trigger this discharge.
Motor Patterns During Flight and Warm-Up in Lepidoptera
Authors: Kammer Ann E.
Published: April 2021

The patterns of muscle activity during warm-up were compared to those of flight. In the skipper Hylephila phylaeus and in the hawk moths Celerio lineata and Mimas tiliae the intervals between bursts of muscle potentials are the same as the wingbeat periods of flight at the same thoracic temperature, and the burst length is the same as in flight. In saturniids the period and burst length are both shorter during wing-vibrating than during flight. During wing-vibrating the amplitude of the wing movement is small, and some of the muscles which are antagonists in flight are active simultaneously. In Hylephila phylaeus and Celerio lineata there is a phase change between some synergistic muscles, while some antagonistic pairs retain the phase relationships of flight. During wing-vibrating in Mimas tiliae and in saturniids all the motor units sampled were active at the same time. In M. tiliae a variety of phase relationships intermediate between those of wing-vibrating and flight were observed, including a case of ‘relative co-ordination’ between motor units in the mesothorax. The results exclude the possibility that a single pace-making centre drives the motor neurons in the flight pattern. A model of the central nervous interactions which generate the observed motor patterns is proposed. It is postulated that a small group of positively coupled neurons produces bursts of impulses at the wingbeat frequency and that these groups interact to generate the phase relationships seen during warm-up and flight.
Sodium regulation in the larvae ofChironomus dorsalis(Meig.) andCamptochironomus tentans(Fabr.): the effect of salt depletion and some observations on temperature changes
Authors: Wright D.A.
Published: April 2021

Sodium regulation was studied in fourth instar larvae of Chironomus dorsalis and Camptochironomus tentans. Both maintain a body sodium level well above that of the surrounding medium. The haemolymph contains approximately 90 % of total body sodium and approximates to a single compartment freely exchanging sodium with the external medium. The anal papillae play a primary role in sodium regulation, the gut being of secondary importance.

Sodium regulation in both species is comparatively insensitive to alterations in acclimatization temperature.

C. dorsalis and C. tentans are capable of maintaining sodium balance in media containing 10 μmole Na and 25 μmole Na respectively.

When exposed to several changes of distilled water, C. tentans is capable of reducing sodium loss by elaboration of a more dilute urine. This is apparently, supplemented by a reduction in the permeability of the body surface. Activation of sodium uptake in both species is comparatively sluggish, with influx reaching a maximum only after the loss of > 30 % body sodium.
Orientation of Demagnetized Bees
Authors: Gould James L. , Kirschvink J. L. , Deffeyes K. S. , Brines M. L.
Published: April 2021

The orientation of honey bee dances is affected by the earth’s magnetic field. Honey bees possess localized, well-oriented, stable and superparamagnetic domains of magnetite. Four lines of evidence suggest that the superparamagnetic domains of bees are more likely to be involved in magnetic field detectors than the stable domains. (1) Although the stable domains vary widely in size and number between bees, approximately 2× 108 superparamagnetic domains are found reliably in all bees, and are restricted to the relatively narrow size range of 300– 350 Å. This suggests that the superparamagnetic domains are more likely to have a biological function. (2) Behavioural observations of dances in null fields are difficult to reconcile with a stable-domain detector but are clearly predicted by many superparamagnetic detector models. (3) When honey bees are demagnetized, their ability to orient to the earth’s field is unaffected. This suggests that the detector either utilizes the superparamagnetic domains or depends on aligned anisotropic stable domains processed without regard to magnetic polarity. (4) Bees that have only superparamagnetic domains are able nevertheless to orient to the earth’s magnetic field, a phenomenon which indicates that permanent domains may not be required for detection.
Neural Control of Radular Retractor Muscles of the Pulmonate Snail, Planorbarius Corneus (L.): Functional Anatomy and Properties of Neuromuscular Units
Authors: Brace R. C. , Quicke D. L. J.
Published: April 2021

The paired supralateral radular retractor muscles of Planorbarius are innervated by eight (four pairs) of buccal motoneurones. Each motoneurone supplies both muscles, the ipsi- and contralateral motor responses being similar, and identical to those produced by its contralateral partner. This arrangement apparently secures equivalence of motor output to the two muscles, irrespective of discrepancies in spiking between homologous motoneurones across the midline, and relates to the strong mechanical linkage between the muscles exerted by the radula. The neuromuscular units are essentially non-overlapping, have properties which range from tonic to phasic, and may act independently providing the flexibility in control required of bifunctional muscles participating in both tensing and retraction of the radula during each feeding cycle.
Coordinated Excitation of Flexor Inhibitors in the Crayfish
Authors: Uyama Chikao , Matsuyama Takashi
Published: April 2021

In isolated abdominal nerve cords of crayfish, the medial or lateral giant axons were stimulated at a position just rostral to the first abdominal ganglion. Recordings of the impulse sequences of the flexor inhibitor (FI) were made from the anterior five ganglia, three ganglia at a time.

In 20% of our preparations, one giant axon impulse caused one to four FI impulses in every abdominal third root. An equal number of FI impulses were usually produced by each abdominal ganglion for any given stimulation.

The earliest FI impulse was observed at the third root of the fourth ganglion. FI impulses occurred with increasing latencies rostrally and caudally from the fourth ganglion.

The FI responses to medial and lateral giant axons stimulation were essentially equivalent.

FI impulses were recorded from the rostral three abdominal ganglia, while the caudal ganglia were cut off one after another from the sixth to the third ganglion. Little change was noted until after the removal of the fourth ganglion, which usually caused all FI impulses to disappear.

From these experimental results, we propose a model of central mechanisms for FI excitation.
Pharmacological Analysis of A Monosynaptic Reflex in the Cockroach, Periplaneta Americana
Authors: Carr Catherine E. , Fourtner Charles R.
Published: April 2021

The monosynaptic connexion between the trochanteral hairplate afferents and the motoneurone Dg was investigated pharmacologically. Electrical stimulation of the hairplate produced a 1:1 reflex activation of Ds which was blocked by saline containing 50 mM-Mg2+. Changes in the hairplate-to-DS reflex and in the tonic activity of DS were monitored during perfusion of drugs known to affect cholinergic transmission. The reflex response was blocked by cholinergic antagonists (atropine, j-tubocurarine, a-bungarotoxin, hexamethonium, decamethonium and TMA); and by an inhibitor of ACh synthesis (hemicholinium-3) ;it was blocked and desensitized by agonists (carbachol and nicotine) and depolarized and blocked by an AChE inhibitor (eserine). These results are consistent with the hypothesis that ACh is a sensory transmitter in the insect CNS.
Connexions Between A Movement-Detecting Visual Interneurone and Flight Motoneurones of A Locust
Authors: Simmons Peter
Published: April 2021

Both of the descending contralateral movement detector (DCMD) neurones of Schistocerca americana gregaria, which respond to stimulation of the contralateral eye or to loud noises, mediate excitatory postsynaptic potentials in most ipsilateral flight motoneurones.
Asymmetric Transfer Hydrogenation of (E)-2-[1,2,6,7-Tetrahydro-8H-indeno[5,4-b]furan-8-ylidene]acetaldehyde Using Polymer-Supported Chiral Pyrrolidine Catalyst
Authors: Haraguchi Naoki , Watanabe Rina , Itsuno Shinichi , Ochiai Hidenori , Nishiyama Akira
Published: April 2021

The asymmetric transfer hydrogenation of α,β-unsaturated aldehyde with Hantzsch ester catalyzed by polymer-supported chiral pyrrolidine organocatalyst was achieved. The effects of the pyrrolidine substituents and linkage configuration on the catalytic performance were examined in detail. We found that the polymer-supported cis-type chiral pyrrolidine organocatalysts showed high enantioselectivities (up to 99.9%) compared with the corresponding trans analogs and monomers in the reaction. The recovered catalyst was reused without any loss of the catalytic activity.