bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hearing with the mouthparts: behavioural responses and the structural basis of ultrasound perception in acherontiine hawkmoths
Authors: Göpfert Martin C. , Wasserthal Lutz T. 
Published: April 2021

ABSTRACT
In contrast to previous assumptions, mouthparts form hearing organs not only in choerocampine hawkmoths but also in some distantly related acherontiine hawkmoth species. Four of the six acherontiine species studied revealed responses to ultrasonic sounds when stimulated during tethered flight. The responses included changes in flight speed and non-directional turns. Individuals from two species also responded by emitting sound. The minimum thresholds of the flight pattern changes were approximately 70 dB in all species studied, with species-specific best frequencies between 30 and 70 kHz. Some acherontiine species also move their tongue in a stereotyped way when stimulated acoustically. The activity of the muscles involved in this tongue reflex was characterized in the present study and used in combination with ablation experiments to localize the hearing organ. These experiments revealed auditory functions of the labial palps and the labral pilifers similar to those found in Choerocampina. The palp contributes a 20–25 dB rise in sensitivity, whereas the pilifer appears to contain the sensory organ. Structural differences suggest a convergent evolution of hearing in hawkmoths: in the place of the swollen palps of Choerocampina, acherontiine species capable of hearing possess a scale-plate of the palps that interacts with an articulating pilifer, while this modification is absent in closely related non-hearing species.
Lack of glomerular intermittency in the river lamprey Lampetra fluviatilis acclimated to sea water and following acute transfer to iso-osmotic brackish water
Authors: Brown J. Anne , Rankin J. Clifford 
Published: April 2021

ABSTRACT
Previous studies have suggested that in the lamprey Lampetra fluviatilis, in contrast to teleost fish, all glomeruli are actively filtering. In the present study, we have applied the ferrocyanide technique to obtain more definitive values for the population of filtering nephrons in the lamprey under conditions of high (in fresh water) and low (in sea water) glomerular filtration rate (GFR) and when the branchial osmotic gradient was eliminated by acute transfer of freshwater lampreys to iso-osmotic brackish water. These studies demonstrated that the renal antidiuresis in lampreys acclimated to full-strength sea water does not involve any reduction in the filtering population of glomeruli. Transfer to brackish water significantly reduced GFR and thereby urine flow rate (287±23 ml kg−1 24 h−1 in fresh water; 6.9±2.5 ml kg−1 24 h−1 in brackish water). In four of the eight fish examined, 100 % of glomeruli remained filtering; in the other four fish, non-filtering glomeruli occurred in patches along the kidney, always associated with an absence of vascular perfusion, which implies possible endocrine/neural control of vascular tone. The numbers of non-filtering glomeruli were always small, and these glomeruli do not appear to make a major contribution to the overall decline in urine output. The results provide firm evidence that although lampreys, like teleosts, show considerable variations in urine output, the renal mechanisms by which lampreys and the teleosts achieve this differ fundamentally, with glomerular intermittency playing little or no part in the lamprey.
Venom of a parasitoid wasp induces prolonged grooming in the cockroach
Authors: Weisel-Eichler Aviva , Haspel Gal , Libersat Frederic 
Published: April 2021

ABSTRACT
The parasitoid wasp Ampulex compressa hunts cockroaches Periplaneta americana, stinging them first in the thorax and then in the head, the sting penetrating towards the subesophageal ganglion. After being stung the cockroach grooms almost continuously for approximately 30 min, performing all the normal components of grooming behavior. This excessive grooming is only seen after the head sting and cannot be attributed to stress, to contamination of the body surface or to systemic or peripheral effects. This suggests that the venom is activating a neural network for grooming.
We suggest that the venom induces prolonged grooming by stimulating dopamine receptors in the cockroach, for the following reasons. (1) Reserpine, which causes massive release of monoamines, induces excessive grooming. (2) Dopamine injected into the hemocoel also induces excessive grooming and is significantly more effective than octopamine or serotonin. In addition, the dopamine agonist SKF 82958 induces excessive grooming when injected directly into the subesophageal ganglion. (3) Injection of the dopamine antagonist flupenthixol greatly reduces venom-induced grooming. (4) Dopamine, or a dopamine-like substance, is present in the venom.
Ionic mechanisms of phototransduction in photoreceptor cells from the epistellar body of the octopus Eledone cirrhosa
Authors: Cobb Christopher S. , Williamson Roddy 
Published: April 2021

ABSTRACT
Intracellular recordings were made from extraocular photoreceptor cells within isolated epistellar bodies of the lesser or northern octopus Eledone cirrhosa. The cells had resting potentials around −41±5 mV (mean ± S.D., N=60) and showed light-flash-induced membrane depolarisation. The evoked response to a brief light flash consisted of a transient peak depolarisation, followed by a plateau component. The magnitude of the light-induced peak depolarisation response was decreased by bathing the epistellar body in artificial sea water (ASW) low in Na+, where choline+ replaced Na+, or by passing steady depolarising current. Replacement of external Na+ by Li+ had no effect on the light-stimulated response. The external application of the Na+ channel blocker tetrodotoxin (3 μmol l−1) increased the light-evoked response, but this was accompanied by a loss of action potential activity. The amplitude and duration of the response to a light flash was increased by bathing the epistellar body in ASW low in Ca2+, or in ASW containing 10 mmol l−1 Co2+, and after intracellular microinjection of the Ca2+ buffer EGTA. Intracellular microinjection of Ca2+ or inositol 1,4,5-trisphosphate, or external application of the phospholipase C inhibitor U-73122, had no apparent effect on the light-evoked response. These results are consistent with the interpretation that (1) the majority of the light-induced inward current is carried by Na+, probably via a non-selective cation channel, and (2) an increase in the intracellular free Ca2+ concentration, mediated by the phototransduction process, is involved in regulating the light-induced inward photocurrent and thus, in effect, determines the amplitude, time course and sensitivity of the receptor potential.
Responsiveness of gill Na+/K+-ATPase to cortisol is related to gill corticosteroid receptor concentration in juvenile rainbow trout
Authors: Shrimpton J. Mark , McCormick Stephen D. 
Published: April 2021

ABSTRACT
A positive relationship between receptor concentration and tissue responsiveness is an often-assumed and rarely tested principle in endocrinology. In salmonids, seasonal changes in levels of plasma cortisol and gill corticosteroid receptors (CRs) during the spring indicate a potential role for this hormone in the parr–smolt transformation. It is not known whether these seasonal changes result in alterations in gill responsiveness to cortisol. The relationship between CR concentration and tissue responsiveness was, therefore, examined in the gills of juvenile rainbow trout (Oncorhynchus mykiss). Gill CR concentration (Bmax) and affinity (Kd) were assessed using a radioligand binding assay with the synthetic glucocorticoid triamcinolone acetonide. Gill responsiveness to cortisol was quantified by measuring in vitro Na+/K+-ATPase activity. Gill CR concentration was manipulated by stress or hormonal treatments. Repeated handling stresses resulted in a significant reduction in CR numbers. The decrease in CR Bmax corresponded to a reduction in gill responsiveness to cortisol. Triiodothyronine, but not growth hormone, treatment was found to increase CR Bmax significantly. The increase in CR numbers was correlated with a marked increase in gill responsiveness to cortisol. A significant positive linear relationship exists between the in vitro gill Na+/K+-ATPase activity response to cortisol and CR Bmax (r2=0.614, P&lt;0.001). We have demonstrated that binding sites for cortisol in the gills of rainbow trout have high affinity, high specificity and saturable binding and that the number of binding sites is correlated with the tissue response to cortisol.
Inhibitory and excitatory responses of olfactory receptor neurons of Xenopus laevis tadpoles to stimulation with amino acids
Authors: Vogler Christina , Schild Detlev 
Published: April 2021

ABSTRACT
Recordings were made from olfactory receptor neurons of Xenopus laevis tadpoles using the patch-clamp technique to investigate the responses of these cells to odorants. Four amino acids (glutamate, methionine, arginine and alanine) both individually and as a mixture were used as stimuli. Of the 156 olfactory neurons tested, 43 showed a response to at least one of the stimuli. Of the cells tested, 19 % responded to glutamate, 16 % to methionine, 12 % to arginine and 10 % to alanine. Each amino acid was able to induce both excitatory and inhibitory responses, although these occurred in different cells. Each amino acid produced approximately equal numbers of inhibitory and excitatory responses. Inhibitory responses could best be observed in the perforated-patch configuration using gramicidin as an ionophore and a recording configuration that is a current-clamp for fast signals and a voltage-clamp for slow signals. The diversity of the odorant responses, in particular the existence of excitatory and inhibitory responses, is not consistent with a single transduction pathway in olfactory neurons of Xenopus laevis tadpoles.
Behaviour of migrating birds exposed to X-band radar and a bright light beam
Authors: Bruderer Bruno , Peter Dieter , Steuri Thomas 
Published: April 2021

ABSTRACT
Radar studies on bird migration assume that the transmitted electromagnetic pulses do not alter the behaviour of the birds, in spite of some worrying reports of observed disturbance. This paper shows that, in the case of the X-band radar ‘Superfledermaus’, no relevant changes in flight behaviour occurred, while a strong light beam provoked important changes.
Large sets of routine recordings of nocturnal bird migrants obtained using an X-band tracking radar provided no indication of differing flight behaviour between birds flying at low levels towards the radar, away from it or passing it sideways. Switching the radar transmission on and off, while continuing to track selected bird targets using a passive infrared camera during the switch-off phases of the radar, showed no difference in the birds’ behaviour with and without incident radar waves.
Tracking single nocturnal migrants while switching on and off a strong searchlight mounted parallel to the radar antenna, however, induced pronounced reactions by the birds: (1) a wide variation of directional shifts averaging 8 ° in the first and 15 ° in the third 10 s interval after switch-on; (2) a mean reduction in flight speed of 2–3 m s−1 (15–30 % of normal air speed); and (3) a slight increase in climbing rate. A calculated index of change declined with distance from the source, suggesting zero reaction beyond approximately 1 km. These results revive existing ideas of using light beams on aircraft to prevent bird strikes and provide arguments against the increasing use of light beams for advertising purposes.
Comparative three-dimensional kinematics of the hindlimb for high-speed bipedal and quadrupedal locomotion of lizards
Authors: Irschick Duncan J. , Jayne Bruce C. 
Published: April 2021

ABSTRACT
Although lizards have been model organisms for testing locomotor performance and in ecomorphological studies, the limb movements of lizards during high-speed locomotion are poorly understood. Thus, we quantified the three-dimensional kinematics of the hindlimb, body and tail for five morphologically distinct species of lizard during steady-speed locomotion near maximum sprinting speed (2–5 m s−1 ). The kinematics of different species had little multivariate overlap. More than half of the strides of all species had digitigrade foot posture, but the frequency of using digitigrade foot posture varied among species. The combination of digitigrade foot posture and large foot size of the lizards contributed substantially to the high values of hip height. For each species, different suites of kinematic variables distinguished bipedal from quadrupedal strides. Interspecific morphological variation did not correspond globally to variation in kinematics, although lizard species with elongated hindlimbs took longer strides than species with shorter hindlimbs. The Froude numbers and relative stride lengths of all lizards running near maximal speeds were large compared with those reported previously for other vertebrates.
Monoamines and the isolated auricle of Sepia officinalis: are there β-like receptors in the heart of a cephalopod?
Authors: Versen B. , Gokorsch S. , Fiedler A. , Schipp R. 
Published: April 2021

ABSTRACT
Pharmacological examinations of isolated auricles from Sepia officinalis were carried out to analyze the putative role of the monoaminergic transmitter/receptor system in the control of auricle function. In conjunction with histofluorescence studies and HPLC analyses, evidence of a double excitatory serotonergic and noradrenergic innervation of the auricles was obtained. Serotonin-induced positive chronotropic and inotropic effects were blocked by mianserin (5-HT1 and 5-HT2) but not by cyproheptadine (5-HT2). It is assumed that the auricular serotonin (5-HT) receptor represents a 5-HT1-like subtype and is not identical to the ventricular 5-HT receptor. Noradrenaline, adrenaline and dopamine evoked mainly positive chronotropic reactions and less prominent positive inotropic reactions. The potency range (pD2 frequency: noradrenaline 6.65 ⪢ adrenaline 5.69 &gt; dopamine 5.34; pD2 amplitude: noradrenaline 6.09 ⩾ adrenaline 5.91 &gt; dopamine 5.33) indicates out that noradrenaline might be the effective neurotransmitter in vivo. The α-mimetics clonidine (α2) and phenylephrine (α1) induced positive chronotropic and inotropic effects, while the β-mimetics albuterol (β2&gt;β1) and dobutamine (β1) revealed only positive inotropic reactions. The β-agonist isoprenaline mimicked the positive chronotropic effects of noradrenaline and induced the strongest positive inotropic effects of all the agonists tested. Urapidil (α1) or phentolamine (α1 and α2) blocked only the positive chronotropic effects of noradrenaline and isoprenaline. The positive inotropic effects of isoprenaline could be blocked by the adenylate cyclase inhibitors MDL-12,330A or SQ-22,536, which had no effect on the chronotropic effects of isoprenaline. These results suggest that two catecholaminergic receptors are present in the auricles of Sepia officinalis: an α-like adrenoreceptor mediating mainly chronotropic effects, and a β-like receptor which appears to mediate inotropic effects by activating the cyclic AMP pathway. These results suggest that the auricles exert a regulatory effect on ventricular performance.
Identification and expression analysis of two developmentally regulated myosin heavy chain gene transcripts in carp (Cyprinus carpio)
Authors: Ennion Steven , Wilkes David , Gauvry Laurent , Alami-Durante Hélene , Goldspink Geoffrey 
Published: April 2021

ABSTRACT
Whilst developmentally regulated genes for the myosin heavy chain (MyoHC) have been characterised in mammalian, avian and amphibian species, no developmental MyoHC gene has previously been characterised in a species of fish. In this study, we identify two developmentally regulated MyoHC gene transcripts (named Eggs22 and Eggs24) in carp (Cyprinus carpio) and characterise their expression patterns during embryonic and larval development. The transcripts showed an identical temporal pattern of expression commencing 22 h post-fertilisation (18 °C incubation temperature), coincident with the switch from exclusive expression of genes for β-actin to expression of genes for both β- and α-actin, and continuing for 2 weeks post-hatching. No expression of these myosin transcripts was detected in juvenile or adult carp. Wholemount in situ hybridisation showed that both transcripts are expressed initially in the rostral region of the developing trunk and progress caudally. Both are expressed in the developing pectoral fin and protractor hyoideus muscles. However, the muscles of the lower jaw express only the Eggs22 transcript. No expression of either transcript was detected in cardiac or smooth muscle. A distinct chevron pattern of expression was observed in the myotomal muscle. This was shown to be caused by localisation of the mRNAs to the myoseptal regions of the fibres, the sites of new sarcomere addition during muscle growth, suggesting transport of MyoHC mRNA transcripts. The 3′ untranslated region of the Eggs24 transcript contains a 10 base pair motif (AAAATGTGAA) which is shown to be also present in the 3′ untranslated regions of MyoHC genes from a wide range of species. Possible reasons for the need for developmental isoforms of myosin heavy chain isoforms are discussed.
Convective oxygen transport and tissue oxygen consumption in Weddell seals during aerobic dives
Authors: Davis Randall W. , Kanatous Shane B. 
Published: April 2021

ABSTRACT
Unlike their terrestrial counterparts, marine mammals stop breathing and reduce their convective oxygen transport while performing activities (e.g. foraging, courtship, aggressive interactions, predator avoidance and migration) that require sustained power output during submergence. Since most voluntary dives are believed to remain aerobic, the goal of this study was to examine the potential importance of the dive response in optimizing the use of blood and muscle oxygen stores during dives involving different levels of muscular exertion. To accomplish this, we designed a numerical model based. on Fick’s principle that integrated cardiac output , regional blood flow, convective oxygen transport , muscle oxymyoglobin d. esaturation and regional rates of oxygen consumption . The model quantified how the optimal matching or mismatching of to affected the aerobic dive limit (ADL). We chose an adult Weddell seal Leptonycotes weddellii on which to base our model because of available data on the diving physiology and metabolism of this species. The results show that the use of blood and muscle oxygen stores must be completed at the same time to maximize the ADL for each level of . This is achieved by adjusting (range 19–94 % of resting levels) and muscle according to the rate of muscle oxygen consumption . At higher values of and muscle perfusion must increase to maintain an appropriate ratio so that available blood and muscle oxygen stores are depleted at the same time. Although the dive response does not sequester blood oxygen exclusively for brain and heart metabolism during aerobic dives, as it does during forced submersion, a reduction in and muscle perfusion below resting levels is necessary to maximize the ADL over the range of diving (approximately 2–9 ml O2 min−1 kg−1). Despite the reduction in , convective oxygen transport is adequate to maintain aerobic metabolism and normal function in the splanchnic organs, kidneys and other peripheral tissues. As a result, physiological homeostasis is maintained throughout the dive. The model shows that the cardiovascular adjustments known as the dive response enable the diving seal to balance the conflicting metabolic demands of (1) optimizing the distribution and use of blood and muscle oxygen stores to maximize the ADL over the normal range of diving and (2) ensuring that active muscle receives adequate oxygen as increases.
Rotation of F1-ATPase and the hinge residues of the β subunit
Authors: Masaike Tomoko , Mitome Noriyo , Noji Hiroyuki , Muneyuki Eiro , Yasuda Ryohei , Kinosita Kazuhiko , Yoshida Masasuke 
Published: April 2021

ABSTRACT
Rotation of a motor protein, F1 -ATPase, was demonstrated using a unique single-molecule observation system. This paper reviews what has been clarified by this system and then focuses on the role of residues at the hinge region of the β subunit. We have visualised rotation of a single molecule of F1 -ATPase by attaching a fluorescent actin filament to the top of the γ subunit in the immobilised F1 -ATPase, thus settling a major controversy regarding the rotary catalysis. The rotation of the γ subunit was exclusively in one direction, as could be predicted by the crystal structure of bovine heart F1 -ATPase. Rotation at low ATP concentrations revealed that one revolution consists of three 120 ° steps, each fuelled by the binding of an ATP to the β subunit. The mean work done by a 120 ° step was approximately 80 pN nm, a value close to the free energy liberated by hydrolysis of one ATP molecule, implying nearly 100 % efficiency of energy conversion. The torque is probably generated by the β subunit, which undergoes large opening–closing domain motion upon binding of AT(D)P. We identified three hinge residues, βHis179, βGly180 and βGly181, whose peptide bond dihedral angles are drastically changed during domain motion. Simultaneous substitution of these residues with alanine resulted in nearly complete loss (99 %) of ATPase activity. Single or double substitution of the two Gly residues did not abolish the ATPase activity. However, reflecting the shift of the equilibrium between the open and closed forms of the β subunit, single substitution caused changes in the propensity to generate the kinetically trapped Mg-ADP inhibited form: Gly180Ala enhanced the propensity and Gly181Ala abolished the propensity. In spite of these changes, the mean rotational torque was not changed significantly for any of the mutants.
Synaptic-Like Microvesicles, Synaptic Vesicle Counterparts in Endocrine Cells, are Involved in a Novel Regulatory Mechanism for the Synthesis and Secretion of Hormones
Authors: Moriyama Yoshinori , Hayashi Mitsuko , Yamada Hiroshi , Yatsushiro Shouki , Ishio Shougo , Yamamoto Akitsugu 
Published: April 2021

ABSTRACT
Microvesicles in endocrine cells are the morphological and functional equivalent of neuronal synaptic vesicles. Microvesicles accumulate various neurotransmitters through a transmitter-specific vesicular transporter energized by vacuolar H+ -ATPase. We found that mammalian pinealocytes, endocrine cells that synthesize and secrete melatonin, accumulate L-glutamate in their microvesicles and secrete it through exocytosis. Pinealocytes use L-glutamate as either a paracrine- or autocrine-like chemical transmitter in a receptor-mediated manner, resulting in inhibition of melatonin synthesis. In this article, we briefly describe the overall features of the microvesicle-mediated signal-transduction mechanism in the pineal gland and discuss the important role of acidic organelles in a novel regulatory mechanism for hormonal synthesis and secretion.