In vivo measurement of lung volume in ringed seals: insights from biomedical imaging [SHORT COMMUNICATION]
Holly Hermann-Sorensen, Nicole M. Thometz, Kathleen Woodie, Sophie Dennison-Gibby, and Colleen Reichmuth Marine mammals rely on oxygen stored in blood, muscle and lungs to support breath-hold diving and foraging at sea. Here, we used biomedical imaging to examine lung oxygen stores and other key respiratory parameters in living ringed seals (Pusa hispida). Three-dimensional models created from computed tomography (CT) images were used to quantify total lung capacity (TLC), respiratory dead space, minimum air volume and total body volume to improve assessment of lung oxygen storage capacity, scaling relationships and buoya...
Source: Journal of Experimental Biology - January 26, 2021 Category: Biology Authors: Hermann-Sorensen, H., Thometz, N. M., Woodie, K., Dennison-Gibby, S., Reichmuth, C. Tags: SHORT COMMUNICATION Source Type: research
Adiposity, reproductive and metabolic health, and activity levels in zoo Asian elephant (Elephas maximus) [RESEARCH ARTICLE]
This study investigated relationships between estimated body composition and metabolic function, inflammatory markers, ovarian activity (females only) and physical activity levels in 44 Asian elephants (n=35 females, n=9 males). Deuterium dilution was used to measure total body water from which fat mass (FM) and fat-free mass (FFM) could be derived to estimate body composition. Serum was analyzed for progestagens and estradiol (females only), deuterium, glucose, insulin and amyloid A. Physical activity was assessed by an accelerometer placed on the elephant's front leg for at least 2 days. Relative fat mass (RFM) &nda...
Source: Journal of Experimental Biology - January 26, 2021 Category: Biology Authors: Chusyd, D. E., Nagy, T. R., Golzarri-Arroyo, L., Dickinson, S. L., Speakman, J. R., Hambly, C., Johnson, M. S., Allison, D. B., Brown, J. L. Tags: RESEARCH ARTICLE Source Type: research
In the field: an interview with Robyn Hetem [CONVERSATION]
Robyn Hetem is a Senior Lecturer at the University of the Witwatersrand, South Africa, where she is a conservation physiologist. After completing her undergraduate degree in Zoology and Physiology, she was appointed as a Researcher in 2008 while completing her PhD at the same university. Hetem has been recognised as a young researcher with the potential to become a future leader in her field by the National Research Foundation in South Africa. Telling us about her research experiences in southern Africa, Hetem reflects on working with species ranging from aardvark to zebra and the challenges they face as a consequence of c...
Source: Journal of Experimental Biology - January 22, 2021 Category: Biology Tags: CONVERSATION Source Type: research
Sex-specific microhabitat use is associated with sex-biased thermal physiology in Anolis lizards [RESEARCH ARTICLE]
We examined microhabitat use and thermal physiology in two ectothermic congeners that are ecologically similar but differ in their degree of sexual size dimorphism. Brown anoles (Anolis sagrei) exhibit male-biased sexual size dimorphism and live in thermally heterogeneous habitats, whereas slender anoles (Anolis apletophallus) are sexually monomorphic in body size and live in thermally homogeneous habitats. We hypothesized that differences in habitat use between the sexes would drive sexual divergence in thermal physiology in brown anoles, but not slender anoles, because male and female brown anoles may be exposed to diver...
Source: Journal of Experimental Biology - January 22, 2021 Category: Biology Authors: Logan, M. L., Neel, L. K., Nicholson, D. J., Stokes, A. J., Miller, C. L., Chung, A. K., Curlis, J. D., Keegan, K. M., Rosso, A. A., Maayan, I., Folfas, E., Williams, C. E., Casement, B., Gallegos Koyner, M. A., Padilla Perez, D. J., Falvey, C. H., Alexan Tags: RESEARCH ARTICLE Source Type: research
Sticking to it: testing passive pull-off forces in waterfall-climbing fishes across challenging substrates [SHORT COMMUNICATION]
In this study, we investigated the influence of surface wettability (hydrophobic versus hydrophilic surface charges) and substrate roughness on the passive adhesive system of four species of gobies with different climbing abilities. Overall, passive adhesive performance varied by species and substrate, with the strongest climbers showing the highest shear pull-off forces, particularly on rough surfaces. Thus, differences in passive adhesive performance may help to explain the ability of some species to migrate further upstream than others and contribute to their ability to invade new habitats. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 21, 2021 Category: Biology Authors: Palecek, A. M., Schoenfuss, H. L., Blob, R. W. Tags: Comparative biomechanics of movement SHORT COMMUNICATION Source Type: research
Three auditory brainstem response (ABR) methods tested and compared in two anuran species [RESEARCH ARTICLE]
In conclusion, the mABR method gave the most sensitive audiograms. The tABR method showed a similar audiogram when using relatively long-duration tone bursts (25 ms). The ltABR method is not a good choice for studying hearing thresholds above 1000 Hz because of the bias introduced by spike rate saturation in the nerve fibers and their inability to phase lock. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 19, 2021 Category: Biology Authors: Lauridsen, T. B., Brandt, C., Christensen-Dalsgaard, J. Tags: RESEARCH ARTICLE Source Type: research
Differing thermal sensitivities of physiological processes alter ATP allocation [RESEARCH ARTICLE]
In this study of developmental stages of the Pacific oyster, Crassostrea gigas, thermal sensitivities were measured for growth, survivorship, protein synthesis, respiration and transport of amino acids and ions. At warmer temperatures, larvae grew faster but suffered increased mortality. An analysis of temperature sensitivity (Q10 values) revealed that protein synthesis, the major ATP-consuming process in larvae of C. gigas, is more sensitive to temperature change (Q10 value of 2.9±0.18) than metabolic rate (Q10 of 2.0±0.15). Ion transport by Na+/K+-ATPase measured in vivo has a Q10 value of 2.1±0.09. ...
Source: Journal of Experimental Biology - January 19, 2021 Category: Biology Authors: Pan, F. T. C., Applebaum, S. L., Manahan, D. T. Tags: RESEARCH ARTICLE Source Type: research
Early developmental stages of native populations of Ciona intestinalis under increased temperature are affected by local habitat history [RESEARCH ARTICLE]
E. A. Clutton, G. Alurralde, and T. Repolho Temperature modulates marine ectotherm physiology, influencing survival, abundance and species distribution. While native species could be susceptible to ocean warming, thermal tolerance might favour the spread of non-native species. Determining the success of invasive species in response to climate change is confounded by the cumulative, synergistic or antagonistic effects of environmental drivers, which vary at a geographical and temporal scale. Thus, an organism's acclimation or adaptive potential could play an important evolutionary role by enabling or conditioning species to...
Source: Journal of Experimental Biology - January 19, 2021 Category: Biology Authors: Clutton, E. A., Alurralde, G., Repolho, T. Tags: RESEARCH ARTICLE Source Type: research
Different fuel regulation in two types of myofiber results in different antioxidant strategies in Daurian ground squirrels (Spermophilus dauricus) during hibernation [RESEARCH ARTICLE]
Shen-Hui Xu, Wei-Wei Fu, Jie Zhang, Hui-Ping Wang, Kai Dang, Hui Chang, and Yun-Fang Gao We previously showed that different skeletal muscles in Daurian ground squirrels (Spermophilus dauricus) possess different antioxidant strategies during hibernation; however, the reason for these varied strategies remains unclear. To clarify this issue, we studied REDD1, FOXO4, PGC-1α, FOXO1 and atrogin-1 proteins to determine the potential cause of the different antioxidant strategies in Daurian ground squirrels during hibernation, and to clarify whether different strategies affect atrophy-related signals. Results showed that t...
Source: Journal of Experimental Biology - January 18, 2021 Category: Biology Authors: Xu, S.-H., Fu, W.-W., Zhang, J., Wang, H.-P., Dang, K., Chang, H., Gao, Y.-F. Tags: RESEARCH ARTICLE Source Type: research
The Murphy number: how pitch moment of inertia dictates quadrupedal walking and running energetics [RESEARCH ARTICLE]
Delyle T. Polet Many quadrupedal mammals transition from a four-beat walk to a two-beat run (e.g. trot), but some transition to a four-beat run (e.g. amble). Recent analysis shows that a two-beat run minimizes work only for animals with a small pitch moment of inertia (MOI), though empirical MOI were not reported. It also remains unclear whether MOI affects gait energetics at slow speeds. Here I show that a particular normalization of the pitch moment of inertia (the Murphy number) has opposite effects on walking and running energetics. During walking, simultaneous fore and hindlimb contacts dampen pitching energy, favouri...
Source: Journal of Experimental Biology - January 18, 2021 Category: Biology Authors: Polet, D. T. Tags: RESEARCH ARTICLE Source Type: research
Omega-3 fatty acids accelerate fledging in an avian marine predator: a potential role of cognition [RESEARCH ARTICLE]
Jessika Lamarre, Sukhinder Kaur Cheema, Gregory J. Robertson, and David R. Wilson Consuming omega-3 fatty acids (n3-LCPUFAs) during development improves cognition in mammals, but the effect remains untested in other taxa. In aquatic ecosystems, n3-LCPUFAs are produced by phytoplankton and bioaccumulate in the food web. Alarmingly, the warming and acidification of aquatic systems caused by climate change impair n3-LCPUFA production, with an anticipated decrease of 80% by the year 2100. We tested whether n3-LCPUFA consumption affects the physiology, morphology, behaviour, and cognition of a top marine predator's chicks, the ...
Source: Journal of Experimental Biology - January 18, 2021 Category: Biology Authors: Lamarre, J., Cheema, S. K., Robertson, G. J., Wilson, D. R. Tags: RESEARCH ARTICLE Source Type: research
Efficient high-voltage protection in the electric catfish [RESEARCH ARTICLE]
Georg Welzel and Stefan Schuster For thousands of years, starting with detailed accounts in the ancient Egypt, the African electric catfish (Malapteruridae) is renowned for its ability to hunt and to defend itself with powerful electric shocks. Surprisingly, it has never been analysed to what degree electric catfish are protected against their own or external electric shocks, how specific any protection would be to the species-specific waveform and whether it requires a discharging catfish to actively prepare for the onset of its high-voltage discharges. Here we used digital high-speed video to record catfish during their ...
Source: Journal of Experimental Biology - January 18, 2021 Category: Biology Authors: Welzel, G., Schuster, S. Tags: RESEARCH ARTICLE Source Type: research
Departures from isotropy: the kinematics of a larval snail in response to food [RESEARCH ARTICLE]
Michelle H. DiBenedetto, Kirstin S. Meyer-Kaiser, Brooke Torjman, Jeanette D. Wheeler, and Lauren S. Mullineaux The swimming behavior of invertebrate larvae can affect their dispersal, survival and settlement in the ocean. Modeling this behavior accurately poses unique challenges as behavior is controlled by both physiology and environmental cues. Some larvae use cilia to both swim and create feeding currents, resulting in potential trade-offs between the two functions. Food availability is naturally patchy and often occurs in shallow horizontal layers in the ocean. Also, larval swimming motions generally differ in the ho...
Source: Journal of Experimental Biology - January 15, 2021 Category: Biology Authors: DiBenedetto, M. H., Meyer-Kaiser, K. S., Torjman, B., Wheeler, J. D., Mullineaux, L. S. Tags: RESEARCH ARTICLE Source Type: research
Strain-specific differences in muscle Ca2+ transport and mitochondrial electron transport chain proteins between FVB/N and C57BL/6J mice [SHORT COMMUNICATION]
Sushant Singh, Muthu Periasamy, and Naresh C. Bal Genetically engineered mouse models have been used to determine the role of sarcolipin (SLN) in muscle. However, a few studies had difficulty in detecting SLN in FBV/N mice and questioned its relevance to muscle metabolism. It is known that genetic alteration of proteins in different inbred mice strains produces dissimilar functional outcomes. Therefore, here we compared the expression of SLN and key proteins involved in Ca2+ handling and mitochondrial metabolism between FVB/N and C57BL/6J mouse strains. Data suggest that SLN expression is less abundant in the skeletal mus...
Source: Journal of Experimental Biology - January 15, 2021 Category: Biology Authors: Singh, S., Periasamy, M., Bal, N. C. Tags: SHORT COMMUNICATION Source Type: research
FreeClimber: automated quantification of climbing performance in Drosophila [METHODS [amp ] TECHNIQUES]
We present an alternative: FreeClimber. This open source, Python-based platform subtracts a video's static background to improve detection for flies moving across heterogeneous backgrounds. FreeClimber calculates a cohort's velocity as the slope of the most linear portion of a mean vertical position versus time curve. It can run from a graphical user interface for optimization or a command line interface for high-throughput and automated batch processing, improving accessibility for users with different expertise. FreeClimber outputs calculated slopes, spot locations for follow-up analyses (e.g. tracking), and several visu...
Source: Journal of Experimental Biology - January 15, 2021 Category: Biology Authors: Spierer, A. N., Yoon, D., Zhu, C.-T., Rand, D. M. Tags: METHODS [amp ] TECHNIQUES Source Type: research