bluuebunny/crossref_metadata_2025 huggingface dataset:
N-Acetylneuraminic Acid (NANA) Stimulates in situ cyclic AMP Production in Tentacles of Sea Anemone (Aiptasia pallida): Possible Role in Chemosensitization of Nematocyst Discharge
Authors: Ozacmak V. Haktan , Thorington Glyne U. , Fletcher William H. , Hessinger David A.
Published: April 2021

Cnidocytes, the stinging cells of cnidarians, optimally discharge nematocysts in response to combined physical contact and stimulation of specific chemoreceptors. In the tentacles of certain sea anemones, the primary chemoreceptors bind N-acetylated sugars, such as N-acetylneuraminic acid (NANA). Sensitization with NANA predisposes contact-sensitive mechanoreceptors (CSMs) to trigger discharge in response to physical contact. In the ectoderm of sea anemone tentacles, cnidocyte/supporting cell complexes (CSCCs) control and trigger nematocyst discharge. Previous findings have implicated cyclic AMP (cAMP) as a second messenger in NANA-sensitized nematocyst discharge. However, no reports have directly demonstrated that the cAMP content of tentacles changes in response to NANA stimulation. We now show that NANA elevates in situ cAMP levels in a dose-dependent manner in the ectoderm of tentacles from the sea anemone Aiptasia pallida. However, the endoderm of tentacles shows no detectable cAMP response to NANA. The effect of NANA on the cAMP content of the ectoderm is biphasic. Micromolar NANA increases the in situ cAMP level, with a maximal response occurring at 1.8×10−5moll−1 NANA. At higher NANA concentrations, the cAMP content decreases to that of controls. Because the cAMP dose/response curve to NANA coincides precisely with the dose/response curves of NANA-sensitized nematocyst discharge and nematocyst-mediated adhesive force, a second-messenger role for cAMP in NANA-sensitized nematocyst discharge is strongly suggested. The addition of isobutyl-1-methylxanthine (IBMX) to the medium with sea anemones increases tissue cAMP levels both in the absence and in the presence of NANA. However, anesthetizing anemones in sea water containing high levels of Mg2+ blocks the NANA-stimulated cAMP response of the ectoderm. In addition, our results suggest that NANA-stimulated cAMP may activate endogenous cAMP-dependent protein kinase (PKA) in broken cell preparations of tentacles. Thus, NANA-stimulated cAMP may function as a second messenger in the NANA chemosensory signaling pathway controlling nematocyst discharge.
Homing in wood ants, Formica japonica: use of the skyline panorama
Authors: Fukushi Tsukasa
Published: April 2021

Homeward orientation was studied in wood ants Formica japonica that, while foraging, shuttled back and forth along a 7.9m route between the nest and a feeding site located on a wide terrace platform surrounded by a conspicuous landmark panorama. The return runs of the ants were amazingly straight, not only in the controls (starting at the feeding site) but also in ants displaced for various distances to the left and right of the feeding site. These courses, however, were oriented neither parallel to the predisplacement courses nor directly towards the nest. This result excludes the use of chemical cues and celestial compass cues. Furthermore, the nest itself, or some object close to it, could not have served as a beacon.

The extensions of the homeward paths taken by ants that had been displaced to various release sites up to 11m sideways from the training route intersected at a point far (approximately 13m) behind the nest. This result suggests that the ants used distant landmarks seen by them in their frontal fields of view.

To test this hypothesis, the distant landmark panorama was concealed by an opaque sheet mounted at right angles to the normal return route of the ants and extending up to different elevations. Shielding the lower part of the landmark panorama had no effect on the homeward paths. However, when the screen was mounted in such a way that the ants could only see the top skyline, represented by the upper edges of a line of trees, for part of their return run, it was only during these parts that their path was oriented in the homeward direction.

When, during the course of displacement experiments, the ants were deprived of their familiar skyline panorama, they moved in their home direction only for an extremely short distance (0.1–0.4m rather than the usual 7.9m) and then started a systematic search programme. Hence, in the present context, skylight information is not used, at least not extensively. Instead, ants use the distant skyline as a navigational guidemark.
Evolution of water balance in the genusDrosophila
Authors: Gibbs Allen G. , Matzkin Luciano M.
Published: April 2021

Fruit flies of the genus Drosophila have independently invaded deserts around the world on numerous occasions. To understand the physiological mechanisms allowing these small organisms to survive and thrive in arid environments, we performed a phylogenetic analysis of water balance in Drosophila species from different habitats. Desert (cactophilic) species were more resistant to desiccation than mesic ones. This resistance could be accomplished in three ways: by increasing the amount of water in the body, by reducing rates of water loss or by tolerating the loss of a greater percentage of body water (dehydration tolerance). Cactophilic Drosophila lost water less rapidly and appeared to be more tolerant of low water content, although males actually contained less water than their mesic congeners. However, when the phylogenetic relationships between the species were taken into account, greater dehydration tolerance was not correlated with increased desiccation resistance. Therefore, only one of the three expected adaptive mechanisms, lower rates of water loss, has actually evolved in desert Drosophila, and the other apparently adaptive difference between arid and mesic species (increased dehydration tolerance) instead reflects phylogenetic history.
Functional mapping of ultraviolet photosensitivity during metamorphic transitions in a salmonid fish,Oncorhynchus mykiss
Authors: Deutschlander Mark E. , Greaves Danielle K. , Haimberger Theodore J. , Hawryshyn Craig W.
Published: April 2021

Ultraviolet visual sensitivity appears to be reduced and, possibly, lost during smoltification in anadromous populations of salmonid fishes. Similar changes occur in non-anadromous salmonids over a mass range that is associated with smoltification in their anadromous conspecifics. However, in sexually mature adult salmonids, ultraviolet-sensitive cones are present in the dorso-temporal retina, suggesting that ultraviolet sensitivity (i) may be regained with sexual maturity or (ii) might never be completely lost. Both smoltification and the transition to sexual maturity are regulated, in part, by the hormone thyroxine. Thyroxine treatment of juvenile Oncorhynchus mykiss results in precocial developmental changes that mimic smoltification, including a reduction of ultraviolet sensitivity. However, whether loss of ultraviolet sensitivity in O. mykiss or in other species of salmonids is complete during normal development (or in response to thyroxine treatment) is unclear. In the present study, we have ‘mapped’ topographically ultraviolet photosensitivity during natural and hormone-induced smoltification. Thyroxine-treated O. mykiss juveniles and anadromous steelhead O. mykiss smolts were examined for ultraviolet visual sensitivity by recording compound action potentials from the optic nerve. By selectively illuminating either the dorsal or the ventral retina, we have shown that the reduction of ultraviolet sensitivity occurs primarily in the ventral retina in both groups of fish. Ultraviolet sensitivity remains intact in the dorsal retina.
Host-plant-derived variation in ultraviolet wing patterns influences mate selection by male butterflies
Authors: Knüttel Helge , Fiedler Konrad
Published: April 2021

We report on the first case in which sequestered secondary plant compounds determine an insect’s external appearance in the ultraviolet spectrum and thereby influence visually mediated mate choice. Larvae of the common blue butterfly Polyommatus icarus specifically sequester flavonoids in different amounts and types, depending on the part or species of food plant. During late pupal development the majority of ultraviolet-absorbing flavonoids are deposited in the wing scales. The flavonoid content of the larval diet thereby determines ultraviolet wing patterns. In laboratory and field experiments, male butterflies clearly preferred flavonoid-rich, ultraviolet-absorbing female dummies. This preference is mediated visually by the ultraviolet pattern of the wings. Food-plant parts and species vary in value as a food source, so ultraviolet wing patterns may signal mate quality and are not a species-specific characteristic.

We discuss the use of principal component analysis in analysing spectral data in the context of visual communication. We propose the alternative application of confidence intervals of averaged spectra as a novel straightforward statistical method for comparing groups of spectra in a manner that is independent of assumptions about the visual system of the receiver. In addition, they can be used to give confidence intervals to derived measures of colour such as quantum catch by photoreceptors.
Polarisation-dependent colour vision inPapiliobutterflies
Authors: Kelber Almut , Thunell Christel , Arikawa Kentaro
Published: April 2021

Butterflies of the genus Papilio have polarisation-sensitive photoreceptors in all regions of the eye, and different spectral types of receptor are sensitive to different e-vector orientations. We have studied the consequences of this eye design for colour vision in behavioural tests and find that Papilio spp. see false colours due to the polarisation of light. They discriminate between vertically and horizontally polarised light of the same colour in the contexts of oviposition and feeding. The discrimination depends on the spectral composition of the stimuli. In the blue and probably in the green range, discrimination does not depend on intensity. However, colour discrimination is influenced by polarisation. Thus, colour and polarisation processing are not separated in the visual system of Papilio spp. From these results, we propose hypotheses about which photoreceptors contribute to colour vision in Papilio spp. and what adaptational value such a system might have for the butterflies. Finally, we give examples for other eyes that have a similar structure.
The effects of the light environment on prey choice by zebra finches
Authors: Maddocks Sam A. , Church Stuart C. , Cuthill Innes C.
Published: April 2021

Recent research has highlighted the extent to which birds utilise ultraviolet vision in mate choice and foraging. However, neither the importance of the ultraviolet compared with other regions of the visual spectrum nor the use of wavelength cues in other visual tasks have been explored. We assessed the individual choices of zebra finches (Taeniopygia guttata) for different-coloured seeds (red and white millet) under lighting conditions in which filters selectively removed blocks of the avian-visible spectrum corresponding to the spectral sensitivity of the four retinal cone types that subserve colour vision in this species. The effects corresponded to those predicted from the calculated distances between seed types, and between each seed type and the background, in a simple model of tetrachromatic colour space. As predicted for this foraging task, the removal of long-wavelength information had a greater influence than the removal of shorter wavelengths, including ultraviolet wavelengths. These results have important implications for predator–prey interactions and suggest that future studies of natural foraging should consider variations in the light environment.
Expression of pineal ultraviolet- and green-like opsins in the pineal organ and retina of teleosts
Authors: Forsell Johan , Ekström Peter , Flamarique Iñigo Novales , Holmqvist Bo
Published: April 2021

In teleostean bony fishes, studies on the adults of various species have shown that pineal photoreceptors are maximally sensitive to short- and middle-wavelength light, possibly utilising both rod-like and pineal-specific opsins. Until recently, however, very little was known about the pineal opsins present in embryonic and larval teleosts and their relationships to opsins expressed by retinal photoreceptors. Our immunocytochemical studies have revealed that, in Atlantic halibut, herring and cod, pineal photoreceptors express principal phototransduction molecules during embryonic life before they appear in retinal photoreceptors. In cDNA from embryonic and adult halibut, we identified two partial opsin gene sequences, HPO1 and HPO4, with highest homology to teleost green and ultraviolet cone opsins (72–83% and 71–83% amino acid identity, respectively). In halibut, these opsins are expressed in the pineal organ of embryos and appear in the retina of larvae. Our recent in situ hybridisation studies with RNA probes for HPO1 and HPO4 demonstrate the presence of green-like opsin mRNAs in the pineal organ and the retina of herring, cod, turbot, haddock, Atlantic salmon, zebrafish and three species of cichlid, and of ultraviolet opsins in the retinas of zebrafish, Atlantic salmon, turbot and the three cichlid species. We conclude that the halibut pineal organ appears to have the potential for both ultraviolet and green photosensitivity from the embryonic stage and that the retina may acquire the same potential during the larval stages. In the other teleosts studied, although both pineal and retinal photoreceptors seem to utilise a green-like opsin from the larval stage, ultraviolet photoreception appears to be restricted to the retina.
The role of extraocular photoreceptors in newt magnetic compass orientation: parallels between light-dependent magnetoreception and polarized light detection in vertebrates
Authors: Phillips John B. , Deutschlander Mark E. , Freake Michael J. , Borland S. Chris
Published: April 2021

Theoretical models implicating specialized photoreceptors in the detection of the geomagnetic field have been the impetus for studying the effects of light on magnetic compass orientation. Magnetic orientation in flies, amphibians and birds has been found to be influenced by light, and in all these groups a shift of approximately 90° in the direction of magnetic compass orientation has been observed under certain wavelengths and/or intensities of light. In the eastern red-spotted newt Notophthalmus viridescens, wavelength-dependent effects of light on magnetic compass orientation appear to result from an antagonistic interaction between short-wavelength (≤450nm) and long-wavelength (≥500nm) photoreception mechanisms. We have demonstrated that at least the short-wavelength input to the newt’s magnetic compass is mediated by extraocular photoreceptors located in or near the pineal organ, and here we present new findings that indicate that the putative long-wavelength mechanism is also associated with pineal photoreceptors. Interestingly, the amphibian pineal organ mediates orientation to both the e-vector of plane-polarized light and the magnetic field. Although the wavelength-dependence of the polarized light orientation in amphibians has not been studied, polarization sensitivity in fishes appears to be mediated by two antagonistic photoreception mechanisms that have similar spectral characteristics to those of the newts’ magnetic compass response. These parallels, along with similarities in the types of receptors that are expected to be involved in light-dependent magnetoreception and polarized light detection, suggest that similar photoreception mechanisms may mediate the light-dependent magnetic and polarized light compasses.
The neuropeptide proctolin induces phosphorylation of a 30 kDa protein associated with the thin filament in crustacean muscle
Authors: Brüstle Berit , Kreissl Sabine , Mykles Donald L. , Rathmayer Werner
Published: April 2021

In the isopod Idotea emarginata, the neuropeptide proctolin is contained in a single pair of motoneurones located in pereion ganglion 4. The two neurones supply dorsal extensor muscle fibres of all segments. Proctolin (1μmoll−1) potentiates the amplitude of contractures of single extensor muscle fibres elicited by 10mmoll−1 caffeine. In western blots of myofibrillar proteins isolated from single muscle fibres and treated with an anti-phosphoserine antibody, a protein with an apparent molecular mass of 30kDa was consistently found. The phosphorylation of this protein was significantly increased by treating the fibres with proctolin. After separation of myofibrillar filaments, a 30kDa protein was found only in the thin filament fraction. This protein is phosphorylated and detected by an antiserum against crustacean troponin I.
Rainbow trout glucose transporter (OnmyGLUT1): functional assessment inXenopus laevisoocytes and expression in fish embryos
Authors: Teerijoki Heli , Krasnov Aleksei , Gorodilov Yuri , Krishna Sanjeev , Mölsä Hannu
Published: April 2021

Recently, we reported the cloning of a putative glucose transporter (OnmyGLUT1) from rainbow trout embryos. In this paper, we describe the functional characteristics of OnmyGLUT1 and its expression during embryonic development of rainbow trout. Transport of d-glucose was analysed in Xenopus laevis oocytes following microinjection of mRNA transcribed in vitro. These experiments confirmed that OnmyGLUT1 is a facilitative Na+-independent transporter. Assessment of substrate selectivity, sensitivity to cytochalasin B and phloretin and kinetic parameters showed that the rainbow trout glucose transporter was similar to a carp transporter and to mammalian GLUT1. Embryonic expression of OnmyGLUT1 was studied using whole-mount in situ hybridization. Ubiquitous distribution of transcripts was observed until the early phase of somitogenesis. During the course of organogenesis, somitic expression decreased along the rostro-caudal axis, finally ceasing in the mature somites. The OnmyGLUT1 transcripts were detected in the neural crest during the whole study period. Transcripts were also found in structures that are likely to originate from the neural crest cells (gill arches, pectoral fins, upper jaw, olfactory organs and primordia of mouth lips). Hexose transport activity was detected at all developmental stages after blastulation. Cytochalasin B blocked the accumulation of phosphorylated 2-deoxy-d-glucose by dissociated embryonic cells, suggesting an important role for transport in glucose metabolism.
Temperature interactions of the molecular chaperone Hsc70 from the eurythermal marine gobyGillichthys mirabilis
Authors: Place Sean P. , Hofmann Gretchen E.
Published: April 2021

Molecular chaperones participate in many aspects of protein biogenesis. Mechanistically, they recognize and bind to non-native proteins, prevent the aggregation of unfolded proteins and also, in some cases, facilitate refolding. Although a great deal is known about the cellular function of molecular chaperones in general, very little is known about the effect of temperature on molecular chaperones in non-model organisms, particularly in ectotherms that fold proteins under variable-temperature conditions in nature. To address this issue, we studied the temperature interactions of a major cytosolic molecular chaperone, Hsc70, from the eurythermal marine goby Gillichthys mirabilis. Using in vitro assays, we measured the intrinsic activity, unfolded-protein-stimulated activity, temperature sensitivity and heat stability of the ATPase activity of native Hsc70 purified from G. mirabilis white muscle. Similar to other chaperones in the 70kDa heat-shock protein family, G. mirabilis Hsc70 exhibited a low intrinsic ATPase activity that was stimulated in vitro by the addition of unfolded protein. Across the environmentally relevant temperature range (10–35°C), the ATPase activity of G. mirabilis Hsc70 displayed differential thermal sensitivity, with the greatest sensitivity occurring between 10 and 15°C and the least sensitivity between 15 and 25°C. In addition, the activity of Hsc70 was not significantly different between the unstimulated and unfolded-protein-stimulated treatments, suggesting that the ATPase activity and the peptide-binding domain of Hsc70 have similar thermal sensitivities in vitro. Finally, the thermal stability of Hsc70 ATPase activity greatly exceeded environmental temperatures for G. mirabilis, with activity up to 62.5°C. Overall, the biochemical characterization of the ATPase activity suggests that, although Hsc70 is not an extraordinarily thermally stable protein, it is capable of protein chaperoning cycles even at the extremes of environmental temperatures encountered by G. mirabilis in nature.
Effects of sublethal ammonia exposure on swimming performance in rainbow trout (Oncorhynchus mykiss)
Authors: Shingles A. , McKenzie D. J. , Taylor E. W. , Moretti A. , Butler P. J. , Ceradini S.
Published: April 2021

Adult trout Oncorhynchus mykiss fitted with a dorsal aortic catheter were exposed to 288±15μmoll−1 (mean ± s.e.m.) total ammonia for 24h in water at a pH of 8.39±0.02, while swimming at a speed equivalent to 0.75bodylengthss−1 (BLs−1) in a Brett-type tunnel respirometer. The fish were then exposed to stepwise increments in swimming speed (0.25BLs−1 every 30min) until exhaustion. Measurements of oxygen uptake (MO2) and plasma total ammonia levels and pH were made at each speed. Control trout were treated identically but without exposure to ammonia. Ammonia exposure caused an increase in plasma total ammonia level to 436±34μmoll−1, compared to 183±30μmoll−1in control animals (N=6). A significant reduction in total plasma ammonia level was found in both groups during exercise, despite a large negative concentration gradient in those exposed to an elevated concentration of ammonia in water, which may indicate an active excretory process. The overall increase in plasma ammonia levels in exposed trout was associated with a significant reduction in critical swimming speed (Ucrit) to 1.61±0.17BLs−1 from 2.23±0.15BLs−1 in control animals. Ammonia-exposed trout had a significantly higher maintenance metabolic rate (MMR) than control fish, when estimated as the y-intercept of the relationship between swimming speed and MO2. Active metabolic rate (AMR, maximum MO2 as measured at Ucrit) was significantly lower in ammonia-exposed animals, leading to a profound reduction in factorial aerobic scope (AMR/MMR). Reduced Ucrit was also linked to a reduction in maximum tailbeat frequency. Calculation of membrane potentials (EM) in the white muscle of fish swum to Ucrit revealed a significant partial depolarisation of white muscle in ammonia-exposed fish. This may have prevented white muscle recruitment and contributed to the reduced maximum tailbeat frequency and overall impairment of swimming performance in the ammonia-exposed fish.
How the clear-sky angle of polarization pattern continues underneath clouds: full-sky measurements and implications for animal orientation
Authors: Pomozi István , Horváth Gábor , Wehner Rüdiger
Published: April 2021

One of the biologically most important parameters of the cloudy sky is the proportion P of the celestial polarization pattern available for use in animal navigation. We evaluated this parameter by measuring the polarization patterns of clear and cloudy skies using 180° (full-sky) imaging polarimetry in the red (650nm), green (550nm) and blue (450nm) ranges of the spectrum under clear and partly cloudy conditions. The resulting data were compared with the corresponding celestial polarization patterns calculated using the single-scattering Rayleigh model. We show convincingly that the pattern of the angle of polarization (e-vectors) in a clear sky continues underneath clouds if regions of the clouds and parts of the airspace between the clouds and the earth surface (being shady at the position of the observer) are directly lit by the sun. The scattering and polarization of direct sunlight on the cloud particles and in the air columns underneath the clouds result in the same e-vector pattern as that present in clear sky. This phenomenon can be exploited for animal navigation if the degree of polarization is higher than the perceptual threshold of the visual system, because the angle rather than the degree of polarization is the most important optical cue used in the polarization compass. Hence, the clouds reduce the extent of sky polarization pattern that is useful for animal orientation much less than has hitherto been assumed. We further demonstrate quantitatively that the shorter the wavelength, the greater the proportion of celestial polarization that can be used by animals under cloudy-sky conditions. As has already been suggested by others, this phenomenon may solve the ultraviolet paradox of polarization vision in insects such as hymenopterans and dipterans. The present study extends previous findings by using the technique of 180° imaging polarimetry to measure and analyse celestial polarization patterns.
Glucagon-like peptide isolated from the eel intestine: effects on atrial beating
Authors: Uesaka Toshihiro , Yano Keiichi , Sugimoto Seiji , Ando Masaaki
Published: April 2021

A new glucagon-like peptide was isolated from the intestine of the eel Anguilla japonica. The primary structure was determined by sequence analysis after cleavage with lysyl endopeptidase, quantitative amino acid analysis and fast atom bombardment mass spectrometry as HSQGTFTNDY10SKYLETRRAQ20DFVQWLMNSK30RSGGPT. Since its structure is similar to that of oxyntomodulins (OXMs) reported in various vertebrates, we named this peptide eel oxyntomodulin (eOXM). We found that eOXM enhanced the contractile force and the beating rate of the eel atrium in a dose-dependent manner. These effects of eOXM were not inhibited by betaxolol, a β1-adrenoceptor antagonist, indicating that the actions of eOXM were independent of those of adrenaline. eOXM enhanced the intracellular Ca2+ concentration of the myocardium. The contractility of the eel atrium was greatly reduced after omitting Ca2+ from the bathing medium or after treatment with verapamil, a Ca2+ channel blocker. After inhibiting Ca2+ entry under these conditions, the inotropic effect of eOXM was markedly reduced, but the chronotropic effect was not altered significantly. These results indicate that the inotropic effect of eOXM is via a stimulation of Ca2+ influx but that the chronotropic effect may be independent of extracellular Ca2+.
Light-dependent magnetoreception in birds: the behaviour of European robins,Erithacus rubecula, under monochromatic light of various wavelengths and intensities
Authors: Wiltschko Wolfgang , Wiltschko Roswitha
Published: April 2021

To investigate how magnetoreception is affected by the wavelength and intensity of light, we tested European robins, Erithacus rubecula, under monochromatic lights of various wavelengths at two intensities using oriented behaviour as an indicator of whether the birds could derive directional information from the geomagnetic field. At a quantal flux of 7×1015 quanta s–1 m–2, the birds were well oriented in their migratory direction east of North under 424 nm blue, 510 nm turquoise and 565 nm green light, whereas they were disoriented under 590 nm yellow light. Increasing the intensity of light at the same wavelengths more than sixfold to 43×1015 quanta s–1 m–2 resulted in a change in behaviour: under bright blue and green light, the birds now showed a preference for the East–West axis, with the majority of headings at the western end; under bright turquoise light, they oriented unimodally towards a direction slightly west of North. Under bright yellow light, the birds continued to be disoriented.

These findings suggest a rather complex relationship between the receptors involved in magnetoreception. Magnetoreception appears to follow rules that are different from those of vision, suggesting that light-dependent magnetoreception may involve receptors and neuronal pathways of its own.
Water acquisition and partitioning inDrosophila melanogaster: effects of selection for desiccation-resistance
Authors: Folk Donna G. , Han Christine , Bradley Timothy J.
Published: April 2021

We examined physiological features related to water balance in five replicate populations of Drosophila melanogaster that have undergone selection for enhanced resistance to desiccation (D populations) and in five replicate control (C) populations. Adult D flies contain 34 % more water than the control flies. We examined two hypotheses for increased water acquisition in the D flies: (i) that they accumulate more water early in development and (ii) that they have a reduced post-eclosion diuretic water loss. We found no evidence of differential water or dry mass acquisition between the C and D populations prior to adulthood. We also found no evidence of differential post-eclosion diuresis, i.e. both C and D groups showed insignificant changes in water volume in the 4 h period immediately after eclosion. In addition, we quantified water content in the intra- and extracellular compartments of the C and D populations and were able to identify the hemolymph as the primary storage site of the ‘extra’ water carried by the desiccation-resistant flies. We estimated that 68 % of the increased water volume observed in the D flies was contained in the hemolymph. Desiccation-resistance was strongly correlated with hemolymph volume and only weakly with intracellular water volume. Survival during desiccation was also strongly related to the carbohydrate content of the D flies. It has been presumed that the D flies accumulate carbohydrate primarily as intracellular glycogen, which would result in a significant increase in intracellular water volume. We found that carbohydrate content was weakly correlated with intracellular water volume and more strongly with hemolymph volume. The carbohydrate pool in the D flies may, therefore, be contained in the extracellular compartment as well as in cells. These results are suggestive of the importance of modifications in hemolymph volume and hemolymph solute concentrations in the evolution of enhanced desiccation-tolerance in populations of Drosophila melanogaster.
Acoustic Detection by Sound-Producing Fishes (Mormyridae): the Role of Gas-Filled Tympanic Bladders
Authors: Fletcher Lindsay B. , Crawford John D.
Published: April 2021

Mormyrid electric fish use sounds for communication and have unusual ears. Each ear has a small gas-filled tympanic bladder coupled to the sacculus. Although it has long been thought that this gas-filled structure confers acoustic pressure sensitivity, this has never been evaluated experimentally. We examined tone detection thresholds by measuring behavioral responses to sounds in normal fish and in fish with manipulations to one or to both of the tympanic bladders. We found that the tympanic bladders increase auditory sensitivity by approximately 30 dB in the middle of the animal’s hearing range (200–1200 Hz). Normal fish had their best tone detection thresholds in the range 400–500 Hz, with thresholds of approximately 60 dB (re 1 μPa). When the gas was displaced from the bladders with physiological saline, the animals showed a dramatic loss of auditory sensitivity. In contrast, control animals in which only one bladder was manipulated or in which a sham operation had been performed on both sides had normal hearing.
Phototransduction in Drosophila melanogaster
Authors: Hardie Roger C.
Published: April 2021

As in most invertebrate microvillar photoreceptors, phototransduction in Drosophila melanogaster uses a G-protein-coupled phosphoinositide pathway, whereby hydrolysis of phosphatidyl inositol 4,5-bisphosphate (PIP2) by phospholipase C generates inositol 1,4,5-trisphosphate (InsP3) and diacyl glycerol (DAG), leading to activation of two classes of Ca2+-permeable light-sensitive channel, encoded by the trp and trpl genes. In some invertebrate photoreceptors, excitation is mediated by release of Ca2+ from intracellular stores by InsP3; however, in Drosophila melanogaster, recent evidence suggests instead that a lipid messenger, such as DAG, its metabolites and/or the reduction in PIP2 levels, may mediate excitation. Like vertebrate rods, Drosophila melanogaster photoreceptors generate quantum bumps in response to single photons, but their kinetics is approximately 10–100 times faster, and this reflects a fundamentally different strategy incorporating a threshold, positive and negative feedback by Ca2+ acting downstream of phospholipase C and a refractory period.
Temperature-dependence of mitochondrial function and production of reactive oxygen species in the intertidal mud clam Mya arenaria
Authors: Abele D. , Heise K. , Pörtner H. O. , Puntarulo S.
Published: April 2021

Mitochondrial respiration, energetic coupling to phosphorylation and the production of reactive oxygen species (ROS) were studied in mitochondria isolated from the eurythermal bivalve Mya arenaria (Myoidea) from a low-shore intertidal population of the German Wadden Sea. Measurements were conducted both within the range of the habitat temperatures (5-15 °C) and when subjected to heat exposure at 20 °C and 25 °C. Experimental warming resulted in an increase in the rate of state 3 and state 4 respiration in isolated mitochondria. The highest respiratory coupling ratios (RCR) were found at 15 °C; at higher temperatures mitochondrial coupling decreased,and release of ROS doubled between 15 and 25 °C. ROS production was 2-3%of total oxygen consumption in state 3 (0.3-0.5 nmol ROS mg-1protein min-1) at the habitat temperature, reaching a maximum of 4.3 % of state 3 respiration and 7 % of oligomycin-induced state 4+respiration under heat stress. Thus, state 4 respiration, previously interpreted exclusively as a measure of proton leakage, included a significant contribution from ROS formation in this animal, especially under conditions of heat stress. Oxygen radical formation was directly dependent on temperature-controlled respiration rates in states 3 and 4 and inversely related to mitochondrial coupling (RCR+) in state 4. Mitochondrial ROS formation is therefore involved in cellular heat stress in this eurythermal marine ectotherm.
Purification of Rhodamine B by Alcohol-Modified Air Bubble Flotation
Authors: Kodama Koki , Oiwa Mako , Saitoh Tohru
Published: April 2021

A simple and rapid method for the purification of a basic dye, Rhodamine B (RB) was developed. It was conducted by adding crude RB to an aqueous solution containing 0.2% (v/v) ethanol followed by air bubble flotation in a cylindrical glass vessel having a sintered glass filter at the bottom. By feeding air bubbles, RB was enriched into foam on the water surfaces within 3 min, while source materials (phthalic acid and N,N-diethyl-3-aminophenol), intermediate compound {2-(4-diethylamino-2-hydroxybenzoyl)}, and other organic impurities remained in the bulk aqueous solution. The foam containing enriched RB was taken up with suction and placed into another flotation vessel for repeated separation. An HPLC-grade RB was successfully obtained by 3-fold air bubble flotation.
The role of orographic barriers in the origin of extreme rainfalls as exemplified by the front of high Eastern Himalaya and the low northern slope of Carpathians
Authors: Cebulak Elżbieta , Gębica Piotr , Limanówka Danuta , Starkel Leszek , Pyrc Robert
Published: April 2021

The paper discusses the role of orographic barriers in generating torrential precipitation in mountainous regions in different climatic zones, the Eastern Himalayas (tropical zone with well-developed monsoon activity) and the northern slope of the Carpathians (temperate zone with transitional climate). Attention has been paid to the different altitudes and courses of the orographic ridges as well as their location relative to the prevailing directions of influx of moist air masses. The cases analysed included torrential rains with monsoon circulation from the S–SW direction at the 2–3 km high edge of the Himalayas, with special consideration to the distance from the margin of the mountains and the exposure of the slopes. They generate frequent flood waves, landslides, debris flows and upbuilding of the alluvial cones in the foreland of the mountain barriers. The impact of the orographic barrier is significantly less marked in the Polish Carpathians. In the western part, the compact edge of the Western Beskids with an altitude of 0.5–1 km and the WSW–NEE course, exposed to moist air masses inflowing from the northern sector, is fragmented eastward into smaller mountain groups, which facilitates the penetration of moist masses of air with occurrence of prolonged precipitation into the mountains. At times, the storm cloud moves along the mountain edge (the margin of the Western Bieszczady Mts.). The marginal scarp of the Foothills has a northern exposure and a height of 150–200 m, and promotes frequent convective precipitation causing local flash floods in small streams. The cases of downpours and high discharges selected for the analysis were those for which there was available a dense network of measuring stations. An insufficient number of stations in constructing precipitation maps based on interpolation would lead to distorting the spatial image. If this were the case, then the role of slope exposure, which has an essential impact on the distribution of precipitation in mountainous regions, would be completely neglected
A global perspective on denudation data, primarily specific sediment yield in mountainous regions
Authors: Slaymaker Olav
Published: April 2021

A brief review of the evolution of denudation research since the 1960s is followed by a review of specific sediment yield variability in mountainous regions of the world as a function of spatial scale, relief, glaciation, lithology and disturbance type and location within the basin. A general model of scalar relations of suspended sediment yield for Canadian regions warns against comparing data from basins with areas ranging over several orders of magnitude. A regional summary of specific sediment yield in mountainous British Columbia confirms that in basins <1 km2 and >30,000 km2 specific sediment yield decreases with basin size whereas in basins of intermediate size (between 1 km² and 30,000 km²) specific sediment yield increases with basin size. This effect is interpreted in terms of three distinct process zones in every mountain basin. These zones can be characterized as a) generally degrading hillslope zones, b) generally aggrading footslopes and valley sides, and c) channelized flows on valley floors demonstrating either net aggradation or degradation. These are identifiable repeating elements in such landscapes. Suspended sediment yield data from mountainous regions around the world are considered in light of the British Columbia model. Some support for the model is found where basins are stratified according to scale, relief, lithology, disturbance types, and location within each basin. Disturbance types include the presence of glaciers, land use activities of various kinds, such as increasing population pressure in the intertropical montane zone, changing population distribution and associated economic activities in the temperate montane zone, and potentially hydroclimate change.
New tools for an integrated vision of the territory: “LANDSCAPP”
Authors: Lugeri Francesca Romana , Farabollini Piero , Lugeri Nicola
Published: April 2021

Landscape is part of everyone’s cultural heritage, if recognized and understood; such consciousness fosters a more creative participation of society in a balanced management of the territory and sustainable development: an important resource in times of crisis. Cognitive tools now enjoy a wide use and offer us a means of immediate communicative diffusion of scientific knowledge relative to an area and an environment. LANDSCApp, a smartphone app, gives the public a chance to try an alternative approach to the knowledge of the natural and cultural territorial heritage, thanks to a set of information related to the geological, morphological, environmental settings of the Italian landscapes.
Conditions for soil erosion by water in the upper Parsęta catchment
Authors: Szpikowski Józef , Majewski Mikołaj , Madaj Wojciech
Published: April 2021

The paper presents potential soil erosion risk of the upper Parsęta catchment (Drawskie Lake District, NW Poland). The model considers following conditions affecting the size of soil erosion: slope gradient, LS factor, lithology, land use and land cover. Thematic maps have been reclassified into a 4-degree division. Potential soil erosion risk map was prepared on the basis of thematic maps. Areas with small and moderate susceptibility to soil erosion occupy 71.5% of the catchment area. The 4th class of erosiveness is represented by the river valley slopes, steep slopes of kame and moraine hills, covering 28.5% of the upper Parsęta catchment.
Debris-flow functioning and their contribution to sedimentary budgets: the Peynin subcatchment of the Guil River (Upper Queyras, Southern French Alps)
Authors: Viel Vincent , Fort Monique , Lissak Candide , Graff Kevin , Carlier Benoît , Arnaud-Fassetta Gilles , Cossart Etienne , Madelin Malika
Published: April 2021

The Peynin catchment (15 km2) is prone to catastrophic floods (June 1957 – Recurrence Interval R.I.>100 yr), June 2000 (R.I.-30 yr) with serious damages to infrastructure and buildings located at the outlet. In this paper, PIT tags tracers and Vensim modelling software are used to better assess the sediment delivery unsteadiness, and more specifically to evaluate the respective role of geomorphological processes on sediment supply during flood event. For the last 20 years, our results highlight a significant variability in sediment delivery from a tributary to another one. According to our studies, we suppose that two torrential tributaries of the Peynin river, the Peyronnelle and Three Arbres subcatchments (<2 km2, representing <15% of the Peynin catchment area) are responsible of 80% of the sediments observed at the outlet of the catchment. Several processes take a part of these sediment transfers, but the efficiency of the sediment cascade in this catchment can be explained by a strong connectivity between sediment erosion area and the main channel of the catchment. Debris and torrential flows triggered during high intensity meteorological event are actually effectively coupled in space and time and guarantee an important sediment supply able to reload the downstream part of the sediment cascade. Recent climate trends, marked by extremes, suggest consequently more damaging events to come, in a context of increasing vulnerable assets
The assessment of influence of soil erosion by water in the transformation of agricultural slopes of the Wiśnicz Foothills
Authors: Święchowicz Jolanta
Published: April 2021

The main aim of the paper is to assess influence of soil erosion by water in the transformation of agricultural slopes of the edge of Wiśnicz Foothills. Low hills are typical in the morphology of the area. Results presented come from measurements of soil erosion by water in 2007–2009. Soil erosion took place during short transformation periods and was caused by events of high magnitude and low frequency during which soil particles are transported from the slope to the channel, but its supply was only local and episodic. In the foothill area slope and channel are weakly linked.
Effectiveness of proprioceptive training and conventional physical therapy in treating adhesive capsulitis
Authors: Shabbir Rida , Arsh Aatik , Darain Haider , Aziz Sadaf
Published: April 2021

Objective: To determine effectiveness of proprioceptive training and conventional physical therapy in managing patients with adhesive capsulitis.

Methods: A pre-test post-test control group study was conducted at Rehman Medical Institute from June to December 2019. Thirty-eight patients, aged 30 to 60 years, with diagnosis of adhesive capsulitis for more than four months were divided into two groups. Subjects in Group-I (conventional group; n=19) received conventional physical therapy protocols for one month while subjects in Group-II (proprioceptive group; n=19) received proprioceptive training along with conventional physical therapy for one month. Disability of Arm Shoulder & Hand questionnaire, Shoulder Pain & Disability Index and goniometer were used at baseline and post-treatment to assess functional activity level, pain & disability and range of motion respectively. Data was analyzed using SPSS version 20.

Results: The mean age of the participants was 53.13 ± 9.12 years. Baseline characteristics were balanced between the two groups. After the treatment, all measures (functional activity level, pain, disability, ROM) improved in both groups. Post treatment, between group analysis showed that functional activity (DASH) and pain (SPADI pain) significantly (P-value <0.05) improved in proprioceptive group as compared to conventional group. However, there were no significant differences (P-value≥ 0.05) in post treatment SPADI disability, SPADI total and ROM (flexion, abduction, external rotation) scores of both groups.

Conclusion: Proprioceptive exercises along with conventional physical therapy are more effective in managing pain and improving functional activities in adhesive capsulitis patients as compared to conventional physical therapy alone.

doi: https://doi.org/10.12669/pjms.37.4.3874

How to cite this:Shabbir R, Arsh A, Darain H, Aziz S. Effectiveness of proprioceptive training and conventional physical therapy in treating adhesive capsulitis. Pak J Med Sci. 2021;37(4):1196-1200. doi: https://doi.org/10.12669/pjms.37.4.3874

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Objective Structured Clinical Examination? How students perceive their learning after OSCE
Authors: Yusuf Lamia
Published: April 2021

Objective: Assessment of skills is an important part of medical education. The objective was to find out how students perceive their learning after being assessed through OSCE.

Methods: It was a mixed convergent parallel study. The study was carried out in the gynaecology department of a private medical college in Lahore. Five groups of final year students posted for rotation in gynae wards were included in this study. Each group comprised of 18 students. They were exposed to OSCE once daily. After completion of one month, students were given a feedback questionnaire (developed and validated by medical educationists) and a focus group discussion was carried out. Eight participants were selected from each group randomly and interviews were recorded. Interviews were transcribed verbatim.

Results: Quantitative data calculated by SPSS 21 and results were calculated as frequencies. Qualitative analysis was based on word frequency count and thematic analysis was followed. Almost 65.2% of the student Shows agreement to the response that OSCE should be part of internal assessments. Whereas 15% shows disagreement and 9% remain neutral. The themes extracted after interviews were, better assessment tool, exam fear, knowledge, confidence and change learning style. thus, triangulating the data. The outcome measured was the result of the final professional of obstetrics and gynaecology year 2017-2018 batch. The success rate was 100% in gynae/obs and one student was able to get a distinction.

Conclusion: Students perceived OSCE as a better assessment tool that increased their knowledge and confidence level. Thus, they were an opinion that OSCE should be part of examinations held in college.

doi: https://doi.org/10.12669/pjms.37.4.4005

How to cite this:Yusuf L. Objective Structured Clinical Examination? How students perceive their learning after OSCE. Pak J Med Sci. 2021;37(4):1206-1210. doi: https://doi.org/10.12669/pjms.37.4.4005

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.