nils-herrmann/clean_scirepeval huggingface dataset:
Transplacental nutrient transfer during gestation in the Andean lizard Mabuya sp. (Squamata, Scincidae)
Venue: Journal of Comparative Physiology B

Mabuya skinks have the most specialized allantoplacenta and the greatest degree of placentotrophy known among the Reptilia. Their recently ovulated eggs are microlecithal (1–2 mm) and lack fatty yolk platelets; thus, virtually all of the nutrients for embryonic development must pass across the placenta. We quantified the net uptake of nutrients during gestation in an Andean population of Mabuya and compared these results with other matrotrophic skinks and eutherian mammals. Total dry and wet masses, ash and organic content, ions (calcium, potassium, sodium, magnesium, iron), lipids (cholesterol, vitamin E and fatty acids in the major lipid classes—triacylglycerol, phospholipids, cholesteryl ester, free fatty acids), nitrogen (an index of protein) were measured during the different developmental stages throughout gestation, and in neonates. A significant net uptake of inorganic and organic matter was found. This uptake begins slowly during early gestation but accelerates during the last third of gestation when the growth of the embryo is maximal and the allantoplacenta has developed its greatest complexity. The drastic reduction of egg size in this clade is related to the great reduction in the contribution of lecithotrophic nutrients to the embryo, an obligatory placentotrophy from early developmental stages, and the highest placental complexity known in the Reptilia. All of these features converge with features found in eutherian mammals.
Sustained swimming improves muscle growth and cellularity in gilthead sea bream
Venue: Journal of Comparative Physiology B

Two groups of juvenile gilthead sea bream were kept on two different swimming regimes (Exercise, E: 1.5 body length s−1 or Control, C: voluntary activity) for 1 month. All fish were first adapted to an experimental diet low in protein and rich in digestible carbohydrates (37.2% protein, 40.4% carbohydrates, 12.5% lipid). The cellularity and capillarisation of white muscle from two selected areas (cranial (Cr), below the dorsal fin, and caudal (Ca), behind the anal fin) were compared. The body weight and specific growth rate (SGR) of group E rose significantly without an increment in feed intake, pointing to higher nutrient-use efficiency. The white muscle fibre cross-sectional area and the perimeter of cranial samples increased after sustained activity, evidencing that sustained exercise enhances hypertrophic muscle development. However, we cannot conclude or rule out the possibility of fibre recruitment because the experimental period was too short. In the control group, capillarisation, which is extremely low in gilthead sea bream white muscle, showed a significantly higher number of fibres with no surrounding capillaries (F0) in the cranial area than in the caudal area, unlike the exercise group. Sustained swimming improved muscle machinery even in tissue normally associated with short bouts of very rapid anaerobic activity. So, through its effect on the use of tissue reserves and nutrients, exercise contributes to improvements in fish growth what can contribute to reducing nitrogen losses.
Organization of the primary somatosensory cortex and wing representation in the Big Brown Bat, Eptesicus fuscus
Venue: Journal of Comparative Physiology A

Bats are the only mammals capable of true powered flight. The bat wing exhibits specializations, allowing these animals to perform complicated flight maneuvers like landing upside-down, and hovering. The wing membrane contains various tactile receptors, including hair-associated Merkel receptors that might be involved in stabilizing bat flight. Here, we studied the neuronal representation of the wing membrane in the primary somatosensory cortex (S1) of the anesthetized Big Brown Bat, Eptesicus fuscus, using tactile stimulation with calibrated monofilaments (von Frey hairs) while recording from multi-neuron clusters. We also measured cortical response thresholds to tactile stimulation of the wings.The body surface is mapped topographically across the surface of S1, with the head, foot, and wing being overrepresented. The orientation of the wing representation is rotated compared to the hand representaion of terrestrial mammals, confirming results from other bat species. Although different wing membrane parts derive embryologically from different body parts, including the flank (plagiopatagium), the tactile sensitivity of the entire flight membrane (0.2–1.2 mN) is remarkably close or even higher (dactylopatagium) than the average tactile sensitivity of the human fingertip.
Fat stores in a migratory bird: a reservoir of carotenoid pigments for times of need?
Venue: Journal of Comparative Physiology B

Carotenoids are well known for their immune-stimulant function in birds and other vertebrates. Moreover, they have potential antioxidant capacity, scavenging free radicals and protecting cell compartments from oxidation. Most essential carotenoids are fat soluble and could be stored for times of need especially in adipose tissues, built up by migratory birds as the main source of energy on long-distance flights. In an exclusive diet experiment, garden warblers (Sylvia borin) were fed ad libitum with an experimental diet, enriched with two different dose rates of carotenoids, or with control food, during the period of their first autumn migration. Plasma carotenoid content was measured via HPLC and chroma of plasma and fat examined with a spectrophotometer. Birds were infected with Isospora spp. and intensity of infection determined by oocyst counts 3 days post infection. Plasma lutein levels and chroma of subcutaneous fat stores were positively correlated and chroma values of these fat stores increased in the birds that got the higher dose rate, whereas they decreased significantly in the control group after infection with Isospora spp. Chroma of subcutaneous fat deposits in vivo and intensity of Isospora infection were negatively correlated. By measuring the chroma of fat deposits in vivo, we show that fat can be a reservoir for carotenoids. These colorful antioxidants are stored in the fat and taken from there in times of a higher demand, e.g. when mounting an immune response to parasites.
Mechanisms of age-specific regulation of dopamine metabolism by juvenile hormone and 20-hydroxyecdysone in Drosophila females
Venue: Journal of Comparative Physiology B

Abstract20-hydroxyecdysone (20E) and the juvenile hormone (JH) have an age-specific effect on total dopamine (DA) content in Drosophila (Gruntenko and Rauschenbach 2008). Earlier we studied the mechanism of influence of 20E and JH on DA metabolism in young females (Rauschenbach et al.  2008a; Gruntenko et al.  2009). Here we investigate the effects of 20E and JH on the activities of the alkaline phosphatase (ALP), tyrosine hydroxylase (TH) and DA-dependent arylalkylamine N-acetyltransferase (AANAT) in mature females of wild type D. virilis under normal conditions and under heat stress (38°C). 20E feeding of the flies led to a substantial decrease in ALP and TH activities and to an increase in AANAT activity in mature females. JH application resulted in an increasing of ALP and TH activities, but did not influence AANAT activity in mature females. A rise in JH and 20E levels was found to change ALP and TH stress reactivities. Mechanisms of age-specific regulation of DA level by 20E and JH in Drosophila females are discussed.
The cranial arterio-venous temperature difference is related to respiratory evaporative heat loss in a panting species, the sheep (Ovis aries)
Venue: Journal of Comparative Physiology B

Panting is a mechanism that increases respiratory evaporative heat loss (REHL) under heat load. Because REHL uses body water, it is physiologically and ecologically relevant to know under what conditions free-ranging animals use panting. We investigated whether the cranial arterio-venous temperature difference could provide information about REHL. We exposed sheep to environments varying in ambient dry bulb temperatures (Env 1: ~15°C, Env 2: ~25°C, Env 3: ~40°C, Env 4: ~40°C + infrared radiation) and measured REHL simultaneously with carotid arterial (Tcar) and jugular venous (Tjug) blood temperatures, as well as brain (Tbrain) and rectal (Trec) temperatures. REHL increased significantly with ambient temperature, from 18.4 ± 4.5 W at Env 1 to 79.5 ± 12.6 W at Env 4 (P < 10−6). While there was no effect of environment on Tcar (P = 0.7) or Tjug (P = 0.09), the difference between them (Ta-v = Tcar − Tjug) increased from Env 1 to Env 2 (P = 0.04) and from Env 3 to Env 4 (P = 0.008). Ta-v reached a maximum of 0.7 ± 0.2°C at Env 4 and was positively correlated with REHL across environments (r2 = 0.78, F = 34.7, P < 10−3). Calculated cranial blood flow changed only from Env 2 to Env 3 (P = 0.002). The increase in REHL maintained homeothermy when dry heat loss decreased. While REHL could increase without generating an increase in Ta-v, any increase in Ta-v was always associated with an increase in REHL. We conclude that the cranial Ta-v provides useful information about REHL in panting animals.
Erythrocyte permeability to urea and water: comparative study in rodents, ruminants, carnivores, humans, and birds
Venue: Journal of Comparative Physiology B

Mammalian erythrocytes exhibit high urea permeability (Purea) due to UT-B expression in their cytoplasmic membrane. This high Purea allows fast equilibration of urea in erythrocytes during their transit in the hyperosmotic renal medulla. It also allows more urea (in addition to that in plasma) to participate in counter-current exchange between ascending and descending vasa recta, thus improving the trapping of urea in the medulla and improving urine concentrating ability. To determine if Purea in erythrocytes is related to diet and urine concentrating ability, we measured Purea in erythrocytes from 11 different mammals and 5 birds using stopped-flow light scattering. Carnivores (dog, fox, cat) exhibited high Purea (in ×10−5 cm/s, 5.3 ± 0.6, 3.8 ± 0.5 and 2.8 ± 0.7, respectively). In contrast, herbivores (cow, donkey, sheep) showed much lower Purea (0.8 ± 0.2, 0.7 ± 0.2, 1.0 ± 0.1, respectively). Erythrocyte Purea in human (1.1 ± 0.2), and pig (1.5 ± 0.1), the two omnivores, was intermediate. Rodents and lagomorphs (mouse, rat, rabbit) had Purea intermediate between carnivores and omnivores (3.3 ± 0.4, 2.5 ± 0.3 and 2.4 ± 0.3, respectively). Birds that do not excrete urea and do not express UT-B in their erythrocytes had very low values (<0.1 × 10−5 cm/s). In contrast to Purea, water permeability, measured simultaneously, was relatively similar in all mammals. The species differences in erythrocytes Purea most probably reflect adaptation to the different types of diet and resulting different needs for concentrating urea in the urine.
Fast and reliable decisions for a dynamic song parameter in field crickets
Venue: Journal of Comparative Physiology A

We investigated the choice of female crickets for a dynamic song parameter (chirp rate) on a walking compensator, and the underlying neuronal basis for the choice in the form of discharge differences in the pair of AN1-neurons driving the phonotactic steering behaviour. Our analysis reveals that decisions about chirp rate in a choice situation are made fast and reliably by female crickets. They steered towards the higher chirp rate after a delay of only 2.2–6 s, depending on the rate difference between the song alternatives. In this time period, the female experienced only one to two additional chirps in the song model with the higher rate. There was a strong correlation between the accumulated AN1 discharge difference and the amount of steering towards the side with the stronger response.
Encoding of amplitude modulations by auditory neurons of the locust: influence of modulation frequency, rise time, and modulation depth
Venue: Journal of Comparative Physiology A

Using modulation transfer functions (MTF), we investigated how sound patterns are processed within the auditory pathway of grasshoppers. Spike rates of auditory receptors and primary-like local neurons did not depend on modulation frequencies while other local and ascending neurons had lowpass, bandpass or bandstop properties. Local neurons exhibited broader dynamic ranges of their rate MTF that extended to higher modulation frequencies than those of most ascending neurons. We found no indication that a filter bank for modulation frequencies may exist in grasshoppers as has been proposed for the auditory system of mammals. The filter properties of half of the neurons changed to an allpass type with a 50% reduction of modulation depths. Contrasting to reports for mammals, the sensitivity to small modulation depths was not enhanced at higher processing stages. In ascending neurons, a focus on the range of low modulation frequencies was visible in the temporal MTFs, which describe the temporal locking of spikes to the signal envelope. To investigate the influence of stimulus rise time, we used rectangularly modulated stimuli instead of sinusoidally modulated ones. Unexpectedly, steep stimulus onsets had only small influence on the shape of MTF curves of 70% of neurons in our sample.
Auditory fovea and Doppler shift compensation: adaptations for flutter detection in echolocating bats using CF-FM signals
Venue: Journal of Comparative Physiology A

Rhythmical modulations in insect echoes caused by the moving wings of fluttering insects are behaviourally relevant information for bats emitting CF-FM signals with a high duty cycle. Transmitter and receiver of the echolocation system in flutter detecting foragers are especially adapted for the processing of flutter information. The adaptations of the transmitter are indicated by a flutter induced increase in duty cycle, and by Doppler shift compensation (DSC) that keeps the carrier frequency of the insect echoes near a reference frequency. An adaptation of the receiver is the auditory fovea on the basilar membrane, a highly expanded frequency representation centred to the reference frequency. The afferent projections from the fovea lead to foveal areas with an overrepresentation of sharply tuned neurons with best frequencies near the reference frequency throughout the entire auditory pathway. These foveal neurons are very sensitive to stimuli with natural and simulated flutter information. The frequency range of the foveal areas with their flutter processing neurons overlaps exactly with the frequency range where DS compensating bats most likely receive echoes from fluttering insects. This tight match indicates that auditory fovea and DSC are adaptations for the detection and evaluation of insects flying in clutter.
Mechanisms of song production in the Australian magpie
Venue: Journal of Comparative Physiology A

Australian magpies (Gymnorhina tibicen) are notable for their vocal prowess. We investigated the syringeal and respiratory dynamics of vocalization by two 6-month-old males, whose songs had a number of adult features. There was no strong lateral syringeal dominance and unilateral phonation was most often achieved by closing the syringeal valve on the contralateral side of the syrinx. Unlike other songbirds studied, magpies sometimes used an alternative syringeal motor pattern during unilateral phonation in which both sides of the syrinx are partially adducted and open to airflow. Also, in contrast to most other songbirds, the higher fundamental frequency during two-voice syllables was usually generated on the left side of the syrinx. Amplitude modulation, a prominent feature of magpie song, was produced by linear or nonlinear interactions between different frequencies which may originate either on opposite sides of the syrinx or on the same side. Pulse tones, similar to vocal fry in human speech, were present in some calls. Unlike small songbirds, the fundamental of the modal frequency can be as low as that of the pulse tone, suggesting that large birds may have evolved pulse tones to increase acoustic diversity, rather than decrease the fundamental frequency.
Complex echo classification by echo-locating bats: a review
Venue: Journal of Comparative Physiology A

Echo-locating bats constantly emit ultrasonic pulses and analyze the returning echoes to detect, localize, and classify objects in their surroundings. Echo classification is essential for bats’ everyday life; for instance, it enables bats to use acoustical landmarks for navigation and to recognize food sources from other objects. Most of the research of echo based object classification in echo-locating bats was done in the context of simple artificial objects. These objects might represent prey, flower, or fruit and are characterized by simple echoes with a single up to several reflectors. Bats, however, must also be able to use echoes that return from complex structures such as plants or other types of background. Such echoes are characterized by superpositions of many reflections that can only be described using a stochastic statistical approach. Scientists have only lately started to address the issue of complex echo classification by echo-locating bats. Some behavioral evidence showing that bats can classify complex echoes has been accumulated and several hypotheses have been suggested as to how they do so. Here, we present a first review of this data. We raise some hypotheses regarding possible interpretations of the data and point out necessary future directions that should be pursued.
A pair of motion-sensitive neurons in the locust encode approaches of a looming object
Venue: Journal of Comparative Physiology A

Neurons in the locust visual system encode approaches of looming stimuli and are implicated in production of escape behaviours. The lobula giant movement detector (LGMD) and its postsynaptic partner, the descending contralateral movement detector (DCMD) compute characteristics of expanding edges across the locust eye during a loom and DCMD synapses onto motor elements associated with behaviour. We identified another descending interneuron within the locust ventral nerve cord. We named this neuron the late DCMD (LDCMD) as it responds later during an approach, with the firing rate peaking at about the time of collision. LDCMD produced lower amplitude, broader action potentials that were associated with an afterhyperpolarization, whereas DCMD action potentials showed a brief afterhyperpolarization often followed by an afterdepolarization. Within the mesothoracic ganglion, the primary LDCMD axon located adjacent to the DCMD axon, was thinner and lacked collateral projections to the lateral region of the neuropil. When compared with DCMD, LDCMD fired with fewer spikes during a loom and showed weaker habituation to repeated approaches. Coincidence of LDCMD and DCMD firing increased during object approach. Our findings indicate the presence of an additional motion-sensitive descending neuron in the locust that encodes temporally distinct properties of an approaching object.
Acoustic-induced motion of the bushcricket (Mecopoda elongata, Tettigoniidae) tympanum
Venue: Journal of Comparative Physiology A

Bushcrickets have a tonotopically organised hearing organ, the so-called crista acustica, in the tibia of the forelegs. This organ responds to a frequency range of about 5–80 kHz and lies behind the anterior tympanum on top of a trachea branch. We analyzed the sound-induced vibration pattern of the anterior tympanum, using a Laser-Doppler-Vibrometer Scanning microscope system, in order to identify frequency-dependent amplitude and phase of displacement. The vibration pattern evoked by a frequency sweep (4–79 kHz) showed an amplitude maximum which would correspond to the resonance frequency of an open tube system. At higher frequencies of about 30 kHz a difference in the amplitude and phase response between the distal and the proximal part of the tympanum was detected. The inner plate of the tympanum starts to wobble at this frequency. This higher mode in the motion pattern is not explained by purely acoustic characteristics of the tracheal space below the tympanum but may depend on the mechanical impedance of the tympanum plate. In accordance with a previous hypothesis, the tympanum moves over the whole tested frequency range in the dorso-ventral direction like a hinged flap with the largest displacement in its ventral part and no higher modes of vibration.
Serotonergic cerebral cells control activity of cilia in the foregut of the pteropod mollusk Clione limacina
Venue: Journal of Comparative Physiology A

Bilaterally symmetrical pair of serotonergic cells, named C1 in Clione, has been described in the cerebral ganglia of all gastropod species. Here we describe a new role of C1 cells in gastropod mollusks: control of activity of ciliated epithelium in the foregut. Detailed morphological investigation of C1 neurons in the pteropod mollusk Clionelimacina revealed that these cells among other destinations send their neurites into foregut where they produce intense arborization with large varicosities along the processes. Intracellular stimulation of a single C1 induced pronounced activation (often followed by inhibition) of cilia lining the foregut. This activation was substantially reduced by serotonin antagonist mianserin. Bath application of serotonin also induced transient increase in ciliary transport rate, followed by inhibition of ciliary activity up to its full cessation in some areas of isolated foregut. These data suggest that C1 in Clione may use serotonin to influence cilia in the foregut. Taking into account high homology of serotonergic cerebral cells across studied species we can speculate that these cells may be involved in the neural control of cilia in the foregut in other gastropod mollusks.
Differential effects of testosterone, dihydrotestosterone and estradiol on carotenoid deposition in an avian sexually selected signal
Venue: Journal of Comparative Physiology A

Recent studies have demonstrated that carotenoid-based traits are under the control of testosterone (T) by up-regulation of carotenoid carriers (lipoproteins) and/or tissue-specific uptake of carotenoids. T can be converted to dihydrotestosterone (DHT) and estradiol (E2), and variation in conversion rate may partly explain some contradictory findings in the literature. Moreover, most studies on the effect of T on sexual signals have focused on the male sex only, while in many species females show the same signal, albeit to a lesser extent. We studied the effects of T, DHT, and E2 treatment in male and female diamond doves Geopelia cuneata in which both sexes have an enlarged red eye ring, which is more pronounced in males. We first showed that this periorbital ring contains very high concentration of carotenoids, of which most are lutein esters. Both T and DHT were effective in enhancing hue, UV-chroma and size in both sexes, while E2 was ineffective. However, E2 dramatically increased the concentration of circulating lipoproteins. We conclude that in both sexes both color and size of the secondary sexual trait are androgen dependent. The action of androgens is independent of lipoproteins regulation. Potential mechanisms and their consequences for trade-off are discussed.