Molecular mechanisms for intestinal HCO3- secretion and its regulation by guanylin in seawater-acclimated eels [RESEARCH ARTICLE]
Yoshio Takei, Marty K. S. Wong, and Masaaki Ando The intestine of marine teleosts secretes HCO3– into the lumen and precipitates Ca2+ and Mg2+ in the imbibed seawater as carbonates to decrease luminal fluid osmolality and facilitate water absorption. However, the hormonal regulation of HCO3– secretion is largely unknown. Here, mucosally added guanylin (GN) increased HCO3– secretion, measured by pH-stat, across isolated seawater-acclimated eel intestine bathed in saline at pH 7.4 (5% CO2). The effect of GN on HCO3– secretion was slower than that on the short-circuit current, and the time course...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Takei, Y., Wong, M. K. S., Ando, M. Tags: RESEARCH ARTICLE Source Type: research

Developmental plasticity in metabolism but not in energy reserve accumulation in a seasonally polyphenic butterfly [RESEARCH ARTICLE]
Sami M. Kivelä, Karl Gotthard, and Philipp Lehmann The evolution of seasonal polyphenisms (discrete phenotypes in different annual generations) associated with alternative developmental pathways of diapause (overwintering) and direct development is favoured in temperate insects. Seasonal life history polyphenisms are common and include faster growth and development under direct development than in diapause. However, the physiological underpinnings of this difference remain poorly known despite its significance for understanding the evolution of polyphenisms. We measured respiration and metabolic rates through the penult...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Kivelä, S. M., Gotthard, K., Lehmann, P. Tags: RESEARCH ARTICLE Source Type: research

Characterization of an evolutionarily conserved calcitonin signalling system in a lophotrochozoan, the Pacific oyster (Crassostrea gigas) [RESEARCH ARTICLE]
Julie Schwartz, Emilie Realis-Doyelle, Marie-Pierre Dubos, Benjamin Lefranc, Jerome Leprince, and Pascal Favrel In Protostoma, the diuretic hormone 31 (DH31) signalling system was long considered as the orthologue of the chordate calcitonin (CT) signalling system. Using the Pacific oyster (Crassostrea gigas) transcriptomic database GigaTON, we characterized seven G-protein-coupled receptors (GPCRs) named Cragi-CTR1–7 and phylogenetically related to chordate CT receptors (CTRs) and to protostome DH31 receptors. Two CT precursors (Cragi-CTP1 and Cragi-CTP2) containing two CT-type peptides and encoded by two distinct g...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Schwartz, J., Realis-Doyelle, E., Dubos, M.-P., Lefranc, B., Leprince, J., Favrel, P. Tags: RESEARCH ARTICLE Source Type: research

Hornets possess long-lasting olfactory memories [RESEARCH ARTICLE]
Zhiwen Gong, Ken Tan, and James C. Nieh The ability of animals to learn and remember is an important adaptation for coping with environmental changes. The fitness benefits provided by these cognitive skills, in conjunction with social behaviours, contribute to the success of social insects. How these abilities are shared among the different castes and the long-term persistence of memory are now being elucidated in diverse systems, work that should shed light on general principles underlying cognitive evolution. Here, we provide the first evidence of olfactory learning and long-term olfactory memory in all three castes of ...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Gong, Z., Tan, K., Nieh, J. C. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

The role of lateral optic flow cues in hawkmoth flight control [RESEARCH ARTICLE]
Anna Stöckl, Rebecca Grittner, and Keram Pfeiffer Flying animals require sensory feedback on changes of their body position, as well as on their distance from nearby objects. The apparent image motion, or optic flow, which is generated as animals move through the air, can provide this information. Flight tunnel experiments have been crucial for our understanding of how insects use optic flow for flight control in confined spaces. However, previous work mainly focused on species from two insect orders: Hymenoptera and Diptera. We therefore set out to investigate whether the previously described control strategies to navi...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Stöckl, A., Grittner, R., Pfeiffer, K. Tags: RESEARCH ARTICLE Source Type: research

Salmonid gene expression biomarkers indicative of physiological responses to changes in salinity and temperature, but not dissolved oxygen [RESEARCH ARTICLE]
Aimee Lee S. Houde, Arash Akbarzadeh, Oliver P. Günther, Shaorong Li, David A. Patterson, Anthony P. Farrell, Scott G. Hinch, and Kristina M. Miller An organism's ability to respond effectively to environmental change is critical to its survival. Yet, life stage and overall condition can dictate tolerance thresholds to heightened environmental stressors, such that stress may not be equally felt across individuals and at all times. Also, the transcriptional responses induced by environmental changes can reflect both generalized responses as well as others that are highly specific to the type of change being experienced. ...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Houde, A. L. S., Akbarzadeh, A., Günther, O. P., Li, S., Patterson, D. A., Farrell, A. P., Hinch, S. G., Miller, K. M. Tags: RESEARCH ARTICLE Source Type: research

Short-term, but not long-term, increased day time workload leads to decreased night time energetics in a free living song bird [RESEARCH ARTICLE]
Marcel E. Visser, Coby van Dooremalen, Barbara M. Tomotani, Andrey Bushuev, Harro A. J. Meijer, Luc te Marvelde, and Phillip Gienapp Reproduction is energetically expensive and to obtain sufficient energy, animals can either alter their metabolic system over time to increase energy intake (increased-intake hypothesis), or reallocate energy from maintenance processes (compensation hypothesis). The first hypothesis predicts a positive relationship between basal metabolic rate (BMR) and energy expenditure (DEE) because of the higher energy demands of the metabolic system in rest. The second hypothesis predicts a trade-off bet...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Visser, M. E., van Dooremalen, C., Tomotani, B. M., Bushuev, A., Meijer, H. A. J., te Marvelde, L., Gienapp, P. Tags: RESEARCH ARTICLE Source Type: research

Contribution of the Achilles tendon to force potentiation in stretch-shortening cycle [RESEARCH ARTICLE]
Atsuki Fukutani, Andrew Sawatsky, Timothy Leonard, and Walter Herzog Muscle force during concentric contractions is potentiated by a preceding eccentric contraction; a phenomenon known as the stretch-shortening cycle (SSC) effect. Tendon elongation is often considered to be the primary factor for this force potentiation. However, direct examination of the influence of tendon elongation on the SSC effect has not been made. The aim of this study was to evaluate the contribution of tendon elongation to the SSC effect by comparing the magnitude of the SSC effect in the rat soleus with and without the Achilles tendon. The rat s...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Fukutani, A., Sawatsky, A., Leonard, T., Herzog, W. Tags: RESEARCH ARTICLE Source Type: research

Overexpression of PGE2 synthase by in vivo transient expression enhances immunocompetency along with fitness cost in a lepidopteran insect [RESEARCH ARTICLE]
This study used in vivo transient expression (IVTE) technique to induce overexpression and assessed subsequent physiological alteration in S. exigua. Se-PGES2 was cloned into a eukaryotic expression vector and transfected to Sf9 cells to monitor its heterologous expression. The Sf9 cells expressed the recombinant Se-PGES2 (rSe-PGES2) at an expected size (~47 kDa), which was localized in cytoplasm. The recombinant expression vector was then used to transfect larvae of S. exigua. Hemocytes collected from the larvae treated with IVTE expressed rSe-PGES2 gene for at least 48 h. The larvae treated with IVTE exhibited an enhance...
Source: Journal of Experimental Biology - July 5, 2019 Category: Biology Authors: Ahmed, S., Hasan, M. A., Kim, Y. Tags: RESEARCH ARTICLE Source Type: research

Upstroke-based acceleration and head stabilization are the norm for the wing-propelled swimming of alcid seabirds [RESEARCH ARTICLE]
Anthony B. Lapsansky and Bret W. Tobalske Alcids, a family of seabirds including murres, guillemots and puffins, exhibit the greatest mass-specific dive depths and durations of any birds or mammals. These impressive diving capabilities have motivated numerous studies on the biomechanics of alcid swimming and diving, with one objective being to compare stroke–acceleration patterns of swimming alcids with those of penguins, where upstroke and downstroke are used for horizontal acceleration. Studies of free-ranging, descending alcids have found that alcids accelerate in the direction of travel during both their upstrok...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Lapsansky, A. B., Tobalske, B. W. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Understanding diversity in oxidative status and oxidative stress: the opportunities and challenges ahead [COMMENTARY]
David Costantini Oxidative stress may be of profound biological relevance. In this Commentary, I discuss some key issues faced by the emerging field of oxidative stress ecology, and seek to provide interpretations and solutions. First, I show that the way in which we define oxidative stress has far-reaching implications for the interpretation of results, and that we need to distinguish between (1) a biochemical definition in terms of the molecular outcomes of oxidative stress (e.g. generation of oxidative damage) and (2) a biological definition in terms of the fitness consequences for the organism (e.g. effects on fertili...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Costantini, D. Tags: COMMENTARY Source Type: research

Evidence that dopamine is involved in neuroendocrine regulation, gill intracellular signaling pathways and ion regulation in Litopenaeus vannamei [RESEARCH ARTICLE]
Lingjun Si, Luqing Pan, Xin Zhang, Hongdan Wang, and Cun Wei The transport of ions and ammonia in the gills may be regulated by neuroendocrine factors, in order to explore the regulation mechanism of dopamine (DA), hemolymph neuroendocrine hormones, gill intracellular signaling pathways, ion and ammonia transporters, as well as hemolymph osmolality and ammonia concentration were investigated in Litopenaeus vannamei after 10–7 and 10–6 mol shrimp–1 DA injection. The data displayed a significant increase in crustacean hyperglycemic hormone (CHH) concentration at 1-12 h and a transient significant decrease i...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Si, L., Pan, L., Zhang, X., Wang, H., Wei, C. Tags: RESEARCH ARTICLE Source Type: research

Ground reaction forces intersect above the center of mass even when walking down visible and camouflaged curbs [RESEARCH ARTICLE]
In this study, eleven volunteers stepped down off a visible (0, 10, and 20 cm) and a camouflaged (0 or 10 cm) curb while walking at two different speeds (1.2±0.1 m s–1 and 1.7±0.1 m s–1). The results showed that in all conditions the GRF pointed predominantly above the COM. Vectors directed from the center of pressure (COP) to the intersection point (IP) closely fitted the measured GRF direction not only in visible conditions (R2>97.5%), but also in camouflaged curb negotiation (R2>89.8%). Additional analysis of variables included in the calculation of the IP location showed considerable dif...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Vielemeyer, J., Griessbach, E., Müller, R. Tags: RESEARCH ARTICLE Source Type: research

Diel cycling hypoxia enhances hypoxia-tolerance in rainbow trout (Oncorhynchus mykiss): evidence of physiological and metabolic plasticity [RESEARCH ARTICLE]
Kenneth J. Williams, Alicia A. Cassidy, Christine E. Verhille, Simon G. Lamarre, and Tyson J. MacCormack Many fish naturally encounter a daily cycle of hypoxia but it is unclear whether this exposure hardens hypoxia-intolerant fish to future hypoxia or leads to accumulated stress and death. Rainbow trout (Oncorhynchus mykiss) is a putatively hypoxia-sensitive species found in rivers and estuaries that may routinely experience hypoxic events. Trout were exposed to 1 of 4 135h treatments in a swim-tunnel respirometer: 1) air-saturated control (20.7 kPa PO2); 2) diel cycling O2 (20.7-4.2 kPa over 24h); 3) acute hypoxia (130h ...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Williams, K. J., Cassidy, A. A., Verhille, C. E., Lamarre, S. G., MacCormack, T. J. Tags: RESEARCH ARTICLE Source Type: research

Light avoidance by non-ocular photosensing system in the terrestrial slug Limax valentianus [RESEARCH ARTICLE]
Haruka Nishiyama, Akane Nagata, Yuko Matsuo, and Ryota Matsuo Although the eye is the best studied photoreceptive organ in animals, the presence of non-ocular photosensing systems has been reported in numerous animal species. However, most of the roles non-ocular photosensory systems play remain elusive. We found that the terrestrial slug Limax valentianus avoids light and escape into dark areas even if it is blinded by the removal of the bilateral superior tentacle. The escape behaviour was more evident for the short-wavelength light. Illumination with blue but not red light, to the head elicited avoidance behaviour in th...
Source: Journal of Experimental Biology - July 2, 2019 Category: Biology Authors: Nishiyama, H., Nagata, A., Matsuo, Y., Matsuo, R. Tags: RESEARCH ARTICLE Source Type: research

Section-specific H+ flux in renal tubules of fasted and fed goldfish [RESEARCH ARTICLE]
Sandra Fehsenfeld, Dennis Kolosov, Chris M. Wood, and Michael J. O'Donnell A recent study demonstrated that in response to a feeding-induced metabolic acidosis, goldfish (Carassius auratus) adjust epithelial protein and/or mRNA expression in their kidney tubules for multiple transporters known to be relevant for acid–base regulation. These include Na+/H+ exchanger (NHE), V-type H+-ATPase (V-ATPase), cytoplasmic carbonic anhydrase, HCO3– transporters and Rhesus proteins. Consequently, renal acid output in the form of protons and NH4+ increases. However, little is known about the mechanistic details of renal aci...
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Fehsenfeld, S., Kolosov, D., Wood, C. M., O'Donnell, M. J. Tags: RESEARCH ARTICLE Source Type: research

Deep breathing in tired trout [OUTSIDE JEB]
Andy Turko (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Turko, A. Tags: OUTSIDE JEB Source Type: research

A soaring success: repeated evolution of island flightlessness [OUTSIDE JEB]
Ilan Ruhr (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Ruhr, I. Tags: OUTSIDE JEB Source Type: research

Pesticides put the bumble back into bumblebees [OUTSIDE JEB]
Alex Evans (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Evans, A. Tags: OUTSIDE JEB Source Type: research

Sit tight: nest temperature affects infection resistance of chicks [OUTSIDE JEB]
Julia Nowack (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Nowack, J. Tags: OUTSIDE JEB Source Type: research

Electrophysiology and transcriptomics reveal two photoreceptor classes and complex visual integration in Hirudo verbana [RESEARCH ARTICLE]
Annette Stowasser, Aaron Stahl, Joshua B. Benoit, and Daniel A. Wagenaar Among animals with visual processing mechanisms, the leech Hirudo verbana is a rare example in which all neurons can be identified. However, little is known about its visual system, which is composed of several pigmented head eyes and photosensitive non-pigmented sensilla that are distributed across its entire body. Although several interneurons are known to respond to visual stimuli, their response properties are poorly understood. Among these, the S cell system is especially intriguing: It is multimodal, spans the entire body of the leech, and is th...
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Stowasser, A., Stahl, A., Benoit, J. B., Wagenaar, D. A. Tags: RESEARCH ARTICLE Source Type: research

What goes up must come down - biomechanical impact analysis of falling locusts [RESEARCH ARTICLE]
In this study we used high-speed recordings to investigate the falling and in particular impact behavior of Schistocerca gregaria locusts, a common model organism for studies on the biomechanics of jumping. Detailed impact analyses of free-falling locusts show that most insects typically crashed onto the substrate. Although free falling locusts tended to spread their legs, they mostly fell onto head and thorax first. The presence of wings did not significantly reduce impact speed, however affected the orientation of the body at impact and significantly reduced the time to recover. Our results also show that alive warm locu...
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: Reichel, S. V., Labisch, S., Dirks, J.-H. Tags: RESEARCH ARTICLE Source Type: research

What determines the basal rate of metabolism? [RESEARCH ARTICLE]
Brian K. McNab The basal rate of metabolism (BMR) is the most reported estimate of energy expenditure in endotherms. Its principal determinant is body mass, but it also correlates with a variety of behavioral not determine basal rate, they are byproducts of the mechanisms that are its determinate. In mammals, mass-independent basal rate increases with muscle mass when it is>40% of body mass. Then basal rates in mammals are≥100% of the values expected from mass. Mammals with muscle masses
Source: Journal of Experimental Biology - July 1, 2019 Category: Biology Authors: McNab, B. K. Tags: RESEARCH ARTICLE Source Type: research

SERCA boosted in chilly chicks flight muscle for warmth [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Influence of stretch magnitude on the stretch-shortening cycle in skinned muscle fibres [RESEARCH ARTICLE]
Atsuki Fukutani and Walter Herzog The mechanical work attained during muscle fibre shortening is increased by prior stretching. Recently, we suggested that residual force enhancement (RFE) may contribute to this enhanced work. RFE can be changed reliably by changing the stretch magnitude. Therefore, the purpose of this study was to examine the effect of stretch magnitude, and by association RFE, on the mechanics of the stretch–shortening cycle (SSC) in skinned skeletal muscle fibres. Three tests were performed using skinned rabbit soleus fibres (N=18). The first test was a pure shortening contraction in which fibres...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Fukutani, A., Herzog, W. Tags: RESEARCH ARTICLE Source Type: research

Sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity during the transition to endothermy in an altricial bird [RESEARCH ARTICLE]
Edwin R. Price, Tushar S. Sirsat, Sarah K. G. Sirsat, and Edward M. Dzialowski Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a transmembrane pump critical to muscle calcium cycling during contraction, and SERCA has also been proposed as the basis for a non-shivering thermogenesis mechanism in birds. Despite its potential importance to both shivering and non-shivering thermogenesis, the activity of this transporter has rarely been studied in altricial birds, and never during the developmental transition from ectothermy to endothermy. Here, we describe SERCA activity in the pectoralis muscle and heart ventricle of red...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Price, E. R., Sirsat, T. S., Sirsat, S. K. G., Dzialowski, E. M. Tags: RESEARCH ARTICLE Source Type: research

Chemically induced plasticity in early life history of Palaemon argentinus: are chemical alarm cues conserved within palaemonid shrimps? [RESEARCH ARTICLE]
Romina B. Ituarte, Maria G. Vazquez, and Claudia C. Bas Most aquatic animals use infochemicals from both conspecifics and heterospecifics to assess local predation risks and enhance predator detection. Released substances from injured conspecifics and other species (chemical alarm cues) are reliable cues to indicate an imminent danger in a specific habitat and often mediate the development of inducible defenses. Amphibian and fish embryos have been shown to acquire this information while at the embryonic stage of development, in relation to the developing nervous system and sensory development. With the exception of Daphn...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Ituarte, R. B., Vazquez, M. G., Bas, C. C. Tags: RESEARCH ARTICLE Source Type: research

Ocean acidification affects calcareous tube growth in adults and reared offspring of serpulid polychaetes [RESEARCH ARTICLE]
Victoria Diaz-Castaneda, T. Erin Cox, Frederic Gazeau, Susan Fitzer, Jeremy Delille, Samir Alliouane, and Jean-Pierre Gattuso The energetically costly transition from free-swimming larvae to a benthic life stage and maintenance of a calcareous structure can make calcifying marine invertebrates vulnerable to ocean acidification. The first goal of this study was to evaluate the impact of ocean acidification on calcified tube growth for two Serpulidae polychaete worms. Spirorbis sp. and Spirobranchus triqueter were collected at 11 m depth from the northwest Mediterranean Sea and maintained for 30 and 90 days at thr...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Diaz-Castaneda, V., Cox, T. E., Gazeau, F., Fitzer, S., Delille, J., Alliouane, S., Gattuso, J.-P. Tags: Ecophysiology: responses to environmental stressors and change RESEARCH ARTICLE Source Type: research

Assessment of fatigue-related biochemical alterations in a rat swimming model under hypoxia [RESEARCH ARTICLE]
Fabo Shan, Tao Yang, Junxia Li, and Qing-Yuan Huang It is well known that exercise-induced fatigue is exacerbated following hypoxia exposure and may arise from central and/or peripheral mechanisms. To assess the relative contribution of peripheral and central factors to exercise-induced fatigue under hypoxia, a rat model of fatigue by a bout of exhaustive swimming was established and fatigue-related biochemical changes in normoxic and severe hypoxic conditions were compared. Rats were randomly divided into four groups, normoxia resting (NR), exhaustive swimming (NE), hypoxia resting (HR) and exhaustive swimming (HE) groups...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Shan, F., Yang, T., Li, J., Huang, Q.-Y. Tags: RESEARCH ARTICLE Source Type: research

Locomotor patterns change over time when exposed to an uneven surface [RESEARCH ARTICLE]
Jenny A. Kent, Joel H. Sommerfeld, Mukul Mukherjee, Kota Z. Takahashi, and Nicholas Stergiou During walking, uneven surfaces impose new demands for controlling balance and forward progression at each step. It is unknown the extent to which walking may be refined given a level of stride-to-stride unpredictability at distal level. Here, we explored the effects of an uneven terrain surface on whole-body locomotor dynamics on immediate exposure and after a familiarization period.Eleven young, unimpaired adults walked for 12 minutes on flat and uneven terrain treadmills. The whole-body center of mass excursion range (COMEXC) an...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Kent, J. A., Sommerfeld, J. H., Mukherjee, M., Takahashi, K. Z., Stergiou, N. Tags: RESEARCH ARTICLE Source Type: research

Histone deacetylase activity is required for Botrylloides leachii whole body regeneration [RESEARCH ARTICLE]
Lisa Zondag, Rebecca Clarke, and Megan J. Wilson The colonial tunicate Botrylloides leachii is exceptional at regenerating from a piece of vascular tunic after loss of all adults from the colony. Previous transcriptome analyses indicate a brief period of healing before regeneration of a new adult (zooid) in as little as 8-10 days. However, there is little understanding of how the resulting changes to gene expression, required to drive regeneration, are initiated and how the overall process is regulated. Rapid changes to transcription often occur in response to chromatin changes, mediated by histone modifications such as hi...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Zondag, L., Clarke, R., Wilson, M. J. Tags: RESEARCH ARTICLE Source Type: research

Strain transformation: Enhancement of invertebrate memory in a new rearing environment [RESEARCH ARTICLE]
Cailin M. Rothwell and Ken Lukowiak Memory formation is influenced by a variety of factors, including the environmental conditions in which an organism is reared. Here, we studied the memory-forming ability of the lab-bred B-strain of Lymnaea following a change in their rearing environment from Brock University to the University of Calgary. We have previously demonstrated that this move enhances memory-forming ability and here we studied the magnitude of this phenotypic change. Once reared to adulthood at the University of Calgary, the B-strain animals were first tested to determine how many training sessions were required...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Rothwell, C. M., Lukowiak, K. Tags: RESEARCH ARTICLE Source Type: research

CB1 and CB2 receptors play differential roles in early zebrafish locomotor development [RESEARCH ARTICLE]
In this study we investigated the roles of the eCB system in zebrafish development by pharmacologically inhibiting the CB1R and CB2Rs (with AM251 and AM630 respectively) in either the first or second day of development. We examined the morphology of motor neurons and we determined neuromuscular outputs by quantifying the amount of swimming in 5 dpf larva. Blocking CB2R during the first day of development resulted in gross morphological deficits and reductions in heart rate that were greater than that following treatment with the CB1R blocker AM251. Blocking CB1Rs from 0 to 24 hpf resulted in an increase in the number of se...
Source: Journal of Experimental Biology - June 28, 2019 Category: Biology Authors: Sufian, M. S., Amin, M. R., Kanyo, R., Allison, W. T., Ali, D. W. Tags: RESEARCH ARTICLE Source Type: research

The photon menace: kleptoplast protection in the photosynthetic sea slug Elysia timida [SHORT COMMUNICATION]
Paulo Cartaxana, Luca Morelli, Bruno Jesus, Goncalo Calado, Ricardo Calado, and Sonia Cruz Absorption of excessive light by photosymbiotic organisms leads to the production of reactive oxygen species that can damage both symbiont and host. This is highly relevant in sacoglossan sea slugs that host functional chloroplasts ‘stolen’ from their algal foods (kleptoplasts), because of limited repair capacities resulting from the absence of algal nuclear genes. Here, we experimentally demonstrate (i) a host-mediated photoprotection mechanism in the photosynthetic sea slug Elysia timida, characterized by the closure o...
Source: Journal of Experimental Biology - June 27, 2019 Category: Biology Authors: Cartaxana, P., Morelli, L., Jesus, B., Calado, G., Calado, R., Cruz, S. Tags: SHORT COMMUNICATION Source Type: research

Comprehensive analysis of genes contributing to euryhalinity in the bull shark, Carcharhinus leucas; Na+-Cl- co-transporter is one of the key renal factors upregulated in acclimation to low-salinity environment [RESEARCH ARTICLE]
Itaru Imaseki, Midori Wakabayashi, Yuichiro Hara, Taro Watanabe, Souichirou Takabe, Keigo Kakumura, Yuki Honda, Keiichi Ueda, Kiyomi Murakumo, Rui Matsumoto, Yosuke Matsumoto, Masaru Nakamura, Wataru Takagi, Shigehiro Kuraku, and Susumu Hyodo Most cartilaginous fishes live principally in seawater (SW) environments, but a limited number of species including the bull shark, Carcharhinus leucas, inhabit both SW and freshwater (FW) environments during their life cycle. Euryhaline elasmobranchs maintain high internal urea and ion levels even in FW environments, but little is known about the osmoregulatory mechanisms that enabl...
Source: Journal of Experimental Biology - June 27, 2019 Category: Biology Authors: Imaseki, I., Wakabayashi, M., Hara, Y., Watanabe, T., Takabe, S., Kakumura, K., Honda, Y., Ueda, K., Murakumo, K., Matsumoto, R., Matsumoto, Y., Nakamura, M., Takagi, W., Kuraku, S., Hyodo, S. Tags: RESEARCH ARTICLE Source Type: research

Differences in ocular media transmittance in classical frog and toad model species and its impact on visual sensitivity [SHORT COMMUNICATION]
Carola A. M. Yovanovich, Taran Grant, and Almut Kelber The transmittance properties of the cornea, lens and humours of vertebrates determine how much light across the visible spectrum reaches the retina, influencing sensitivity to visual stimuli. Amphibians are the only vertebrate class in which the light transmittance of these ocular media has not been thoroughly characterised, preventing large-scale comparative studies and precise quantification of visual stimuli in physiological and behavioural experiments. We measured the ocular media transmittance in some commonly used species of amphibians (the bufonids Bufo bufo an...
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: Yovanovich, C. A. M., Grant, T., Kelber, A. Tags: SHORT COMMUNICATION Source Type: research

Muscular apoptosis but not oxidative stress increases with old age in a long-lived diver, the Weddell seal [RESEARCH ARTICLE]
Kaitlin N. Allen, Jose Pablo Vazquez-Medina, John M. Lawler, Jo-Ann E. Mellish, Markus Horning, and Allyson G. Hindle Seals experience repeated bouts of ischemia–reperfusion while diving, potentially exposing their tissues to increased oxidant generation and thus oxidative damage and accelerated aging. We contrasted markers of oxidative damage with antioxidant profiles across age and sex for propulsive (longissismus dorsi) and maneuvering (pectoralis) muscles of Weddell seals to determine whether previously observed morphological senescence is associated with oxidative stress. In longissismus dorsi, old (age 17&ndas...
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: Allen, K. N., Vazquez-Medina, J. P., Lawler, J. M., Mellish, J.-A. E., Horning, M., Hindle, A. G. Tags: RESEARCH ARTICLE Source Type: research

Finding the peak of dynamic oxygen uptake during fatiguing exercise in fish [METHODS AND TECHNIQUES]
Yangfan Zhang, Matthew J. H. Gilbert, and Anthony P. Farrell As fish approach fatigue at high water velocities in a critical swimming speed (Ucrit) test, their swimming mode and oxygen cascade typically move to an unsteady state because they adopt an unsteady, burst-and-glide swimming mode despite a constant, imposed workload. However, conventional rate of oxygen uptake (MO2) sampling intervals (5–20 min) tend to smooth any dynamic fluctuations in active MO2 (MO2active) and thus likely underestimate the peak MO2active. Here, we used rainbow trout (Oncorhynchus mykiss) to explore the dynamic nature of MO2ac...
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: Zhang, Y., Gilbert, M. J. H., Farrell, A. P. Tags: METHODS AND TECHNIQUES Source Type: research

Prior reproduction alters how mitochondria respond to an oxidative event [RESEARCH ARTICLE]
Wendy R. Hood, Yufeng Zhang, Halie A. Taylor, Noel R. Park, Abby E. Beatty, Ryan J. Weaver, Kang Nian Yap, and Andreas N. Kavazis An animal's pace of life is mediated by the physiological demands and stressors it experiences (e.g. reproduction) and one likely mechanism that underlies these effects is oxidative stress. Reproduction has been shown to increase or reduce oxidative stress under different conditions and to modify mitochondrial performance. We hypothesized that the changes associated with reproduction can alter how animals respond to future oxidative stressors. We tested this theory by comparing the organ-specif...
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: Hood, W. R., Zhang, Y., Taylor, H. A., Park, N. R., Beatty, A. E., Weaver, R. J., Yap, K. N., Kavazis, A. N. Tags: RESEARCH ARTICLE Source Type: research

PPAR expression, muscle size, and metabolic rates across the Gray catbird's annual cycle are greatest in preparation for fall migration [RESEARCH ARTICLE]
Kristen DeMoranville, Keely R. Corder, Angelica Hamilton, David E. Russell, Janice M. Huss, and Paul J. Schaeffer Phenotypic flexibility across the annual cycle allows birds to adjust to fluctuating ecological demands. Varying energetic demands associated with time of year have been demonstrated to drive metabolic and muscle plasticity in birds, but it remains unclear what molecular mechanisms control this flexibility. We sampled Gray catbirds at five stages across their annual cycle: tropical wintering (January), northward spring (late) migration (early May), breeding (mid June), the fall pre-migratory period (early Augus...
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: DeMoranville, K., Corder, K. R., Hamilton, A., Russell, D. E., Huss, J. M., Schaeffer, P. J. Tags: RESEARCH ARTICLE Source Type: research

Phenotypic plasticity in the invasive pest Drosophila suzukii: activity rhythms and gene expression in response to temperature [RESEARCH ARTICLE]
C. Plantamp, H. Henri, T. Andrieux, C. Regis, G. Mialdea, S. Dray, P. Gibert, and E. Desouhant Phenotypic plasticity may contribute to the invasive success of an alien species in a new environment. A higher plastic species may survive and reproduce in more diverse environments, thereby supporting establishment and colonization. We focused on plasticity in the circadian rhythm of activity, which can favour species coexistence in invasion, for the invasive species Drosophila suzukii, which is expected to be a weaker direct competitor than other Drosophila species of the resident community. We compared between the invasive D....
Source: Journal of Experimental Biology - June 25, 2019 Category: Biology Authors: Plantamp, C., Henri, H., Andrieux, T., Regis, C., Mialdea, G., Dray, S., Gibert, P., Desouhant, E. Tags: RESEARCH ARTICLE Source Type: research

Antioxidant capacity and anoxia tolerance in Austrofundulus limnaeus embryos [RESEARCH ARTICLE]
Josiah T. Wagner, Michael J. Knapp, and Jason E. Podrabsky Embryos of Austrofundulus limnaeus can tolerate extreme environmental stresses by entering into a state of metabolic and developmental arrest known as diapause. Oxidative stress is ubiquitous in aerobic organisms and the unique biology and ecology of A. limnaeus likely results in frequent and repeated exposures to oxidative stress during development. The antioxidant capacity of A. limnaeus was explored during development by measuring antioxidant capacity due to small molecules and several enzymatic antioxidant systems. Diapause II embryos can survive for several d...
Source: Journal of Experimental Biology - June 24, 2019 Category: Biology Authors: Wagner, J. T., Knapp, M. J., Podrabsky, J. E. Tags: RESEARCH ARTICLE Source Type: research

Seasonal muscle ultrastructure plasticity and resistance of muscle structural changes during temperature increases in resident black-capped chickadees and rock pigeons [RESEARCH ARTICLE]
Ana Gabriela Jimenez, Erin S. O'Connor, Karl J. Brown, and Christopher W. Briggs Resident birds in temperate zones respond to seasonally fluctuating temperatures by adjusting their physiology, such as changes in basal metabolic rate or peak metabolic rate during cold exposure, or altering their organ sizes, so as to match the thermogenic requirements of their current environment. Climate change is predicted to cause increases in the frequency of heat and cold wave events, which could increase the likelihood that birds will face an environmental mismatch. Here, we examined seasonality and the effects of acute and chronic h...
Source: Journal of Experimental Biology - June 24, 2019 Category: Biology Authors: Jimenez, A. G., O'Connor, E. S., Brown, K. J., Briggs, C. W. Tags: RESEARCH ARTICLE Source Type: research

Transplanting gravid lizards to high elevation alters maternal and embryonic oxygen physiology, but not reproductive success or hatchling phenotype [RESEARCH ARTICLE]
Laura Kouyoumdjian, Eric J. Gangloff, Jeremie Souchet, Gerardo A. Cordero, Andreaz Dupoue, and Fabien Aubret Increased global temperatures have opened previously inhospitable habitats, such as at higher elevations. However, the reduction of oxygen partial pressure with increase in elevation represents an important physiological constraint that may limit colonization of such habitats, even if the thermal niche is appropriate. To test the mechanisms underlying the response to ecologically-relevant levels of hypoxia, we performed a translocation experiment with the common wall lizard (Podarcis muralis), a widespread European ...
Source: Journal of Experimental Biology - June 24, 2019 Category: Biology Authors: Kouyoumdjian, L., Gangloff, E. J., Souchet, J., Cordero, G. A., Dupoue, A., Aubret, F. Tags: RESEARCH ARTICLE Source Type: research

Acetoin is a key odor for resource location in the giant robber crab Birgus latro [SHORT COMMUNICATION]
Markus Knaden, Sonja Bisch-Knaden, Jeanine Linz, Andreas Reinecke, Jakob Krieger, Susanne Erland, Steffen Harzsch, and Bill S. Hansson The terrestrial and omnivorous robber crab Birgus latro inhabits islands of the Indian Ocean and the Pacific Ocean. The animals live solitarily but occasionally gather at freshly opened coconuts or fructiferous arenga palms. By analyzing volatiles of coconuts and arenga fruit, we identified five compounds, including acetoin, which are present in both food sources. In a behavioral screen performed in the crabs' habitat, a beach on Christmas Island, we found that of 15 tested fruit compounds...
Source: Journal of Experimental Biology - June 21, 2019 Category: Biology Authors: Knaden, M., Bisch-Knaden, S., Linz, J., Reinecke, A., Krieger, J., Erland, S., Harzsch, S., Hansson, B. S. Tags: SHORT COMMUNICATION Source Type: research

ATP-induced reversed thermal sensitivity of O2 binding in both major haemoglobin polymorphs of the non-endothermic Atlantic cod, Gadus morhua [RESEARCH ARTICLE]
Charlotte Nelson, Samantha L. Barlow, and Michael Berenbrink Atlantic cod is a species that is affected by climate change, with some populations being exposed to higher temperatures than others. The two polymorphs of its major haemoglobin type (HbI) show an inverse change in frequency along a latitudinal temperature cline in the North East Atlantic, which has been associated with differences in population performance and behavioural traits. An earlier study at the northern distribution limit of the species reported differential temperature sensitivities of red blood cell oxygen (O2) affinity between the northern cold-wate...
Source: Journal of Experimental Biology - June 21, 2019 Category: Biology Authors: Nelson, C., Barlow, S. L., Berenbrink, M. Tags: Ecophysiology: responses to environmental stressors and change RESEARCH ARTICLE Source Type: research

Early-career researchers: an interview with Cosima Porteus [CONVERSATION]
Cosima Porteus is a Postdoctoral Fellow at the University of Exeter, UK, where she studies how fish sense, interact with and respond to their environment. She received her Bachelor's degree in Marine and Freshwater Biology from the University of Guelph, Canada, in 2004 before completing her Master's degree in Integrative Biology in 2006 at the same institution with Don Stevens and Pat Wright. After completing a PhD with Bill Milsom at the University of British Columbia, Canada, in 2012, Porteus joined Rod Wilson at the University of Exeter, UK, for a postdoctoral fellowship. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - June 20, 2019 Category: Biology Tags: CONVERSATION Source Type: research

How poison dart frogs export potent poisons to their skins [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - June 20, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Molecular physiology of chemical defenses in a poison frog [RESEARCH ARTICLE]
Stephanie N. Caty, Aurora Alvarez-Buylla, Gary D. Byrd, Charles Vidoudez, Alexandre B. Roland, Elicio E. Tapia, Bogdan Budnik, Sunia A. Trauger, Luis A. Coloma, and Lauren A. O'Connell Poison frogs sequester small molecule lipophilic alkaloids from their diet of leaf litter arthropods for use as chemical defenses against predation. Although the dietary acquisition of chemical defenses in poison frogs is well documented, the physiological mechanisms of alkaloid sequestration has not been investigated. Here, we used RNA sequencing and proteomics to determine how alkaloids impact mRNA or protein abundance in the little devil...
Source: Journal of Experimental Biology - June 20, 2019 Category: Biology Authors: Caty, S. N., Alvarez-Buylla, A., Byrd, G. D., Vidoudez, C., Roland, A. B., Tapia, E. E., Budnik, B., Trauger, S. A., Coloma, L. A., O'Connell, L. A. Tags: RESEARCH ARTICLE Source Type: research

Ventilatory sensitivity to ammonia in the Pacific hagfish (Eptatretus stoutii), a representative of the oldest extant connection to the ancestral vertebrates [RESEARCH ARTICLE]
Junho Eom, Marina Giacomin, Alexander M. Clifford, Greg G. Goss, and Chris M. Wood Ventilatory sensitivity to ammonia occurs in teleosts, elasmobranchs, and mammals. Here we investigated whether the response is present in hagfish. Ventilatory parameters (nostril flow, pressure amplitude, velar frequency, and ventilatory index, the latter representing the product of pressure amplitude times frequency), together with blood and water chemistry, were measured in hagfish exposed to either high environmental ammonia (HEA) in the external sea water or internal ammonia loading by intra-vascular injection. HEA exposure (10 mM NH4HC...
Source: Journal of Experimental Biology - June 20, 2019 Category: Biology Authors: Eom, J., Giacomin, M., Clifford, A. M., Goss, G. G., Wood, C. M. Tags: RESEARCH ARTICLE Source Type: research