nils-herrmann/clean_scirepeval huggingface dataset:
GH–IGF system regulation of attenuated muscle growth and lipolysis in Atlantic salmon reared at elevated sea temperatures
Venue: Journal of Comparative Physiology B

Growth regulation in adult Atlantic salmon (1.6 kg) was investigated during 45 days in seawater at 13, 15, 17, and 19 °C. We focused on feed intake, nutrient uptake, nutrient utilization, and endocrine regulation through growth hormone (GH), insulin-like growth factors (IGF), and IGF-binding proteins (IGFBP). During prolonged thermal exposure, salmon reduced feed intake and growth. Feed utilization was reduced at 19 °C after 45 days compared with fish at lower temperatures, and body lipid storage was depleted with increasing water temperature. Although plasma IGF-1 concentrations did not change, 32-Da and 43-kDa IGFBP increased in fish reared at ≤17 °C, and dropped in fish reared at 19 °C. Muscle igf1 mRNA levels were reduced at 15 and 45 days in fish reared at 15, 17, and 19 °C. Muscle igf2 mRNA levels did not change after 15 days in response to increasing temperature, but were reduced after 45 days. Although liver igf2 mRNA levels were reduced with increasing temperatures after 15 and 45 days, temperature had no effect on igf1 mRNA levels. The liver igfbp2b mRNA level, which corresponds to circulating 43-kDa IGFBP, exhibited similar responses after 45 days. IGFBP of 23 kDa was only detected in plasma in fish reared at 17 °C, and up-regulation of the corresponding igfbp1b gene indicated a time-dependent catabolic response, which was not observed in fish reared at 19 °C. However, higher muscle ghr mRNA levels were detected in fish at 17 and 19 °C than in fish at lower temperatures, indicating lipolytic regulation in muscle. These results show that the reduction of muscle growth in large salmon is mediated by decreased igf1 and igf2 mRNA levels in addition to GH-associated lipolytic action to cope with prolonged thermal exposure. Accordingly, 13 °C appears to be a more optimal temperature for the growth of adult Atlantic salmon at sea.
Encephalopsin (OPN3) protein abundance in the adult mouse brain
Venue: Journal of Comparative Physiology A

Encephalopsin belongs to the family of extraretinal opsins having a putative role in CNS tissue photosensitivity. Encephalopsin mRNA has earlier been localized in rodent brains, but expression and localization of the protein has not yet been reported. In this study, we aimed to define encephalopsin protein abundance and localization in the rodent brain. The distribution and localization of encephalopsin protein in a mouse brain and selected peripheral tissues were analysed in ten mice, using Western blotting and immunohistochemistry. The specificity of immunoreaction was validated by primary antibody omitting and immunizing peptide blocking experiment. We found encephalopsin protein abundant in the mouse brain, but not in the periphery. Encephalopsin protein was present in neurons of the mouse cerebral cortex, paraventricular area, and cerebellar cells. Our results show that encephalopsin is expressed at the protein level in different brain areas of the mouse. Therefore, the suggested idea that encephalopsin plays a role in non-visual photic processes seems to be applicable. Evidently, further investigations are needed to find out the signalling mechanisms, and the potential physiological role of encephalopsin in phototransduction due to the changes in ambient light.
Distributions of active spinal cord neurons during swimming and scratching motor patterns
Venue: Journal of Comparative Physiology A

The spinal cord can generate motor patterns underlying several kinds of limb movements. Many spinal interneurons are multifunctional, contributing to multiple limb movements, but others are specialized. It is unclear whether anatomical distributions of activated neurons differ for different limb movements. We examined distributions of activated neurons for locomotion and scratching using an activity-dependent dye. Adult turtles were stimulated to generate repeatedly forward swimming, rostral scratching, pocket scratching, or caudal scratching motor patterns, while sulforhodamine 101 was applied to the spinal cord. Sulforhodamine-labeled neurons were widely distributed rostrocaudally, dorsoventrally, and mediolaterally after each motor pattern, concentrated bilaterally in the deep dorsal horn, the lateral intermediate zone, and the dorsal to middle ventral horn. Labeled neurons were common in all hindlimb enlargement segments and the pre-enlargement segment following swimming and scratching, but a significantly higher percentage were in the rostral segments following swimming than rostral scratching. These findings suggest that largely the same spinal regions are activated during swimming and scratching, but there are some differences that may indicate locations of behaviorally specialized neurons. Finally, the substantial inter-animal variability following a single kind of motor pattern may indicate that essentially the same motor output is generated by anatomically variable networks.
Hibernation patterns of Turkish hamsters: influence of sex and ambient temperature
Venue: Journal of Comparative Physiology B

Turkish hamsters (Mesocricetus brandti) are a model organism for studies of hibernation, yet a detailed account of their torpor characteristics has not been undertaken. This study employed continuous telemetric monitoring of body temperature (Tb) in hibernating male and female Turkish hamsters at ambient temperatures (Tas) of 5 and 13 °C to precisely characterize torpor bout depth, duration, and frequency, as well as rates of entry into and arousal from torpor. Hamsters generated brief intervals of short (<12 h), shallow test bouts (Tb > 20 °C), followed by deep torpor bouts lasting 4–6 days at Ta = 5 °C and 2–3 days at Ta = 13 °C. Females at Ta = 5 °C had longer bouts than males, but maintained higher torpor Tb; there were no sex differences at Ta = 13 °C. Neither body mass loss nor food intake differed between the two Tas. Hamsters entered torpor primarily during the scotophase (subjective night), but timing of arousals was highly variable. Hamsters at both Tas generated short, shallow torpor bouts between deep bouts, suggesting that this species may be capable of both hibernation and daily torpor.
Visual flight control in naturalistic and artificial environments
Venue: Journal of Comparative Physiology A

Although the visual flight control strategies of flying insects have evolved to cope with the complexity of the natural world, studies investigating this behaviour have typically been performed indoors using simplified two-dimensional artificial visual stimuli. How well do the results from these studies reflect the natural behaviour of flying insects considering the radical differences in contrast, spatial composition, colour and dimensionality between these visual environments? Here, we aim to answer this question by investigating the effect of three- and two-dimensional naturalistic and artificial scenes on bumblebee flight control in an outdoor setting and compare the results with those of similar experiments performed in an indoor setting. In particular, we focus on investigating the effect of axial (front-to-back) visual motion cues on ground speed and centring behaviour. Our results suggest that, in general, ground speed control and centring behaviour in bumblebees is not affected by whether the visual scene is two- or three dimensional, naturalistic or artificial, or whether the experiment is conducted indoors or outdoors. The only effect that we observe between naturalistic and artificial scenes on flight control is that when the visual scene is three-dimensional and the visual information on the floor is minimised, bumblebees fly further from the midline of the tunnel. The findings presented here have implications not only for understanding the mechanisms of visual flight control in bumblebees, but also for the results of past and future investigations into visually guided flight control in other insects.
Corneal microprojections in coleoid cephalopods
Venue: Journal of Comparative Physiology A

The cornea is the first optical element in the path of light entering the eye, playing a role in image formation and protection. Corneas of vertebrate simple camera-type eyes possess microprojections on the outer surface in the form of microridges, microvilli, and microplicae. Corneas of invertebrates, which have simple or compound eyes, or both, may be featureless or may possess microprojections in the form of nipples. It was previously unknown whether cephalopods (invertebrates with camera-type eyes like vertebrates) possess corneal microprojections and, if so, of what form. Using scanning electron microscopy, we examined corneas of a range of cephalopods and discovered nipple-like microprojections in all species. In some species, nipples were like those described on arthropod compound eyes, with a regular hexagonal arrangement and sizes ranging from 75 to 103 nm in diameter. In others, nipples were nodule shaped and irregularly distributed. Although terrestrial invertebrate nipples create an antireflective surface that may play a role in camouflage, no such optical function can be assigned to cephalopod nipples due to refractive index similarities of corneas and water. Their function may be to increase surface-area-to-volume ratio of corneal epithelial cells to increase nutrient, gas, and metabolite exchange, and/or stabilize the corneal mucous layer, as proposed for corneal microprojections of vertebrates.
Central representation of spatial and temporal surface wave parameters in the African clawed frog
Venue: Journal of Comparative Physiology A

Xenopus laevis employs mechano-sensory lateral lines to, for instance, capture arthropods on the surface of turbid waters with poor visibility based on incoming wave signals. To characterise central representations of surface waves emitted from different locations, responses to several wave parameters were extracellularly recorded across brainstem, midbrain and thalamic areas. Overall, 339 of 411 statistically analysed responses showed significantly altered spike rates during the presentation of surface waves. Of these units, 45.1 % were obtained in the torus semicircularis including its laminar subnucleus (23.3 %) that is known to process auditory cues. Wave parameters contributing to central object representations were indicated by response rates that systematically varied with amplitude (76.3 % of 160 tested units), frequency (74.4 % of 270 tested units), source angle (93.7 % of 79 tested units), or source distance (63.8 % of 218 tested units). Map-like parameter representations were rather diffuse, yet an increased fraction of units tuned to frontal source angles was observed at deeper tissue layers (>180 μm), and an increased fraction of best neuronal responses to low wave frequencies (≤25 Hz) at rostral midbrain sections. Responses to wave frequencies remained largely robust across tested unit samples independent of source angles, and distances (N = 62). In comparison, spatial response characteristics seemed fragile across different wave frequencies in 68.3 % of 41 recordings.
Expression of genes involved in energy mobilization and osmoprotectant synthesis during thermal and dehydration stress in the Antarctic midge, Belgica antarctica
Venue: Journal of Comparative Physiology B

The Antarctic midge, Belgica antarctica, experiences sub-zero temperatures and desiccating conditions for much of the year, and in response to these environmental insults, larvae undergo rapid shifts in metabolism, mobilizing carbohydrate energy reserves to promote synthesis of low-molecular-mass osmoprotectants. In this study, we measured the expression of 11 metabolic genes in response to thermal and dehydration stress. During both heat and cold stress, we observed upregulation of phosphoenolpyruvate carboxykinase (pepck) and glycogen phosphorylase (gp) to support rapid glucose mobilization. In contrast, there was a general downregulation of pathways related to polyol, trehalose, and proline synthesis during both high- and low-temperature stress. Pepck was likewise upregulated in response to different types of dehydration stress; however, for many of the other genes, expression patterns depended on the nature of dehydration stress. Following fast dehydration, expression patterns were similar to those observed during thermal stress, i.e., upregulation of gp accompanied by downregulation of trehalose and proline synthetic genes. In contrast, gradual, prolonged dehydration (both at a constant temperature and in conjunction with chilling) promoted marked upregulation of genes responsible for trehalose and proline synthesis. On the whole, our data agree with known metabolic adaptations to stress in B. antarctica, although a few discrepancies between gene expression patterns and downstream metabolite contents point to fluxes that are not controlled at the level of transcription.
The tradeoff between torpor use and reproduction in little brown bats (Myotis lucifugus)
Venue: Journal of Comparative Physiology B

In mammals, reproduction, especially for females is energetically demanding. Therefore, during the reproductive period females could potentially adjust patterns of thermoregulation and foraging in concert to minimise the energetic constraints associated with pregnancy and lactation. We assessed the influence of pregnancy, lactation, and post-lactation on torpor use and foraging behaviour by female little brown bats, Myotis lucifugus. We measured thermoregulation by recording skin temperature and foraging by tracking bats which carried temperature-sensitive radio-tags. We found that individuals, regardless of reproductive condition, used torpor, but the patterns of torpor use varied significantly between reproductive (pregnant and lactating) females and post-lactating females. As we predicted, reproductive females entered torpor for shorter bouts than post-lactating females. Although all females used torpor frequently, pregnant females spent less time in torpor, and maintained higher skin temperatures than either lactating or post-lactating females. This result suggests that delayed offspring development which has been associated with torpor use during pregnancy, may pose a higher risk to an individual’s reproductive success than reduced milk production during lactation. Conversely, foraging behaviour of radio-tagged bats did not vary with reproductive condition, suggesting that even short, shallow bouts of torpor produce substantial energy savings, likely obviating the need to spend more time foraging. Our data clearly show that torpor use and reproduction are not mutually exclusive and that torpor use (no matter how short or shallow) is an important means of balancing the costs of reproduction for M. lucifugus.
Coexpression of three middle wavelength-absorbing visual pigments in sexually dimorphic photoreceptors of the butterfly Colias erate
Venue: Journal of Comparative Physiology A

The tiered ommatidia of the Eastern Pale Clouded yellow butterfly, Colias erate, contain nine photoreceptor cells, four of which contribute their rhabdomeral microvilli to the distal tier of the rhabdom. We analyzed the visual pigments and spectral sensitivities of these distal photoreceptors in both sexes of Colias erate. A subset of photoreceptor cells expresses a newly discovered middle wavelength-absorbing opsin, ColiaserateBlue (CeB), in addition to two previously described middle wavelength-absorbing opsins, CeV1 and CeV2. The other photoreceptors either coexpress CeV1 and CeV2, or exclusively express a short wavelength-absorbing opsin, CeUV, or a long wavelength-absorbing opsin, CeL. Males and females have the same visual pigment expression patterns, but the photoreceptor spectral sensitivities are sexually dimorphic. The photoreceptors coexpressing three middle wavelength-absorbing opsins are broad-blue receptors in males, but in females they are narrow-blue receptors. Those with CeV1 and CeV2 are violet receptors in females, while they are shouldered-blue receptors in males. The sexual dimorphism in spectral sensitivity is caused by a sex-specific distribution of fluorescent pigment that functions as a spectral filter.
Neuropeptide Y-induced feeding is dependent on GABAA receptors in neonatal chicks
Venue: Journal of Comparative Physiology A

In mammals and birds, neuropeptide Y (NPY) and gamma-aminobutyric acid (GABA) are found in brain areas known to be involved in the control of ingestive behavior and act to increase voluntary food intake. In rats, significant evidence suggest a functional and behavioral interaction between NPY and GABA mediated transmission in various brain regions, including the arcuate and paraventricular nuclei of the hypothalamus which can be important in the regulation of feeding behavior. In the present study, the effect of intracerebroventricular (ICV) administration of NPY and GABA receptor antagonists on food intake was examined in neonatal chicks. The ICV injection of NPY strongly stimulated food intake while co-administration of NPY and picrotoxin, a GABAA antagonist, (but not CGP54626, a GABAB antagonist) weakened food intake induced by NPY. These results suggest that central NPY stimulates food intake in neonatal chicks by interaction with the GABAergic system via GABAA receptors.
Sink or swim: a test of tadpole behavioral responses to predator cues and potential alarm pheromones from skin secretions
Venue: Journal of Comparative Physiology A

Chemical signaling is a vital mode of communication for most organisms, including larval amphibians. However, few studies have determined the identity or source of chemical compounds signaling amphibian defensive behaviors, in particular, whether alarm pheromones can be actively secreted from tadpoles signaling danger to conspecifics. Here we exposed tadpoles of the common toad Bufo bufo and common frog Rana temporaria to known cues signaling predation risk and to potential alarm pheromones. In both species, an immediate reduction in swimming activity extending over an hour was caused by chemical cues from the predator Aeshna cyanea (dragonfly larvae) that had been feeding on conspecific tadpoles. However, B. bufo tadpoles did not detectably alter their behavior upon exposure to potential alarm pheromones, neither to their own skin secretions, nor to the abundant predator-defense peptide bradykinin. Thus, chemicals signaling active predation had a stronger effect than general alarm secretions of other common toad tadpoles. This species may invest in a defensive strategy alternative to communication by alarm pheromones, given that Bufonidae are toxic to some predators and not known to produce defensive skin peptides. Comparative behavioral physiology of amphibian alarm responses may elucidate functional trade-offs in pheromone production and the evolution of chemical communication.
Calling song signals and temporal preference functions in the cricket Teleogryllus leo
Venue: Journal of Comparative Physiology A

The acoustic display of many cricket species consists of trains of pulses (chirps) with intermittent pauses. Here, we investigated the temporal cues that females of the cricket Teleogryllus leo used to detect a pulse and a chirp pattern on two different time scales. For both patterns, females accepted a wide range of combinations that covered the respective pulse and chirp parameters in the songs of males. In tests with a continuous series of pulses at different modulation frequencies, the transfer function of pattern discrimination was also determined. Females exhibited two ranges of high response scores indicating two temporal filters with an inhibitory interaction. For the modulation frequency of the pulse pattern, the peak of the preference function was rather sharply tuned and at a lower pulse rate than produced by males. These results show that the combined output of both filters did not increase selectivity, but rather enlarged the accepted range of signals.
Age- and behaviour-related changes in the expression of biogenic amine receptor genes in the antennae of honey bees (Apis mellifera)
Venue: Journal of Comparative Physiology A

We recently identified changes in amine-receptor gene expression in the antennae of the honey bee that correlate with shifts in the behavioural responsiveness of worker bees towards queen mandibular pheromone. Here we examine whether variations in expression of amine-receptor genes are related to age and/or to behavioural state. Colonies with a normal age structure were used to collect bees of different ages, as well as pollen foragers of unknown age. Single- and double-cohort colonies were established also to generate nurses and pollen foragers of the same age. Amdop1 was the only gene examined that showed no significant change in expression levels across the age groups tested. However, expression of this gene was significantly higher in 6-day-old nurses than in pollen foragers of the same age. Levels of expression of Amdop2 were very variable, particularly during the first week of adult life, and showed no correlation with nursing or foraging behaviour. Amdop3 and Amtyr1 expression levels changed dramatically with age. Interestingly, Amtyr1 expression was significantly higher in 15-day-old pollen foragers than in same-age nurses, whereas the opposite was true for Amoa1. While Amoa1 expression in the antennae was lower in 6- and 15-day-old pollen foragers than in nurses of the same age, differences in gene expression levels between nurses and pollen foragers could not be detected in 22-day-old bees. Our data show dynamic modulation of gene expression in the antennae of worker bees and suggest a peripheral role for biogenic amines in regulating behavioural plasticity in the honey bee.
Paternal deprivation alters play-fighting, serum corticosterone and the expression of hypothalamic vasopressin and oxytocin in juvenile male mandarin voles
Venue: Journal of Comparative Physiology A

Although early paternal deprivation significantly affects offspring behavioral and neuroendocrine development, the link between paternal deprivation and social play behavior remains unclear. Mandarin voles (Microtus mandarinus) are socially monogamous and display bi-paternal care. The present study examined the development of social play in juvenile male mandarin voles and the paternal influence on play-fighting, vasopressin- and oxytocin-immunoreactive neurons and serum corticosterone and testosterone levels. The results show that social play was more pronounced during postnatal days 28–35, differing from the ontogenetic pattern of other forms of social behavior. On postnatal day 35, the peak in play-fighting activity, paternal deprivation reduced boxing/wrestling levels and vasopressin-immunoreactive neurons in the anterior hypothalamus and oxytocin-immunoreactive neurons in the paraventricular nucleus, but increased vasopressin-immunoreactive neurons in the paraventricular nucleus and corticosterone levels. These results suggest that mandarin voles engage in social play according to an inverted U-shaped curve in ontogeny, and paternal deprivation influences the development of offspring play-fighting; hypothalamic vasopressin, oxytocin and serum corticosterone may play a modulatory role in the alteration of play-fighting elicited by paternal deprivation; decreased play-fighting may correlate with depressed vasopressin levels in the anterior hypothalamus.