Recently, abundant evidence has clarified that long noncoding RNAs (lncRNAs) play an oncogenic or anticancer role in the tumorigenesis and development of diverse human cancers. Described as a crucial regulator in some cancers, MIR22HG has not yet been studied in laryngocarcinoma and therefore the underlying regulatory role of MIR22HG in laryngocarcinoma is worth detecting. In this study, MIR22HG expression in laryngocarcinoma cells was confirmed to be downregulated, and upregulated MIR22HG expression led to suppressive effects on laryngocarcinoma cell proliferation and migration. Molecular mechanism assays revealed that MIR22HG sponges miR-5000-3p in laryngocarcinoma cells. Besides, decreased expression of miR-5000-3p suppressed laryngocarcinoma cell proliferation and migration. Moreover, the FBXW7 gene was reported to be a downstream target gene of miR-5000-3p in laryngocarcinoma cells. More importantly, rescue assays verified that FBXW7 depletion or miR-5000-3p upregulation countervailed the repressive effects of MIR22HG overexpression on laryngocarcinoma progression. In addition, E2F6 was proved to be capable of inhibiting MIR22HG transcription in laryngocarcinoma cells. To sum up, E2F6-induced downregulation of MIR22HG promotes laryngocarcinoma progression through the miR-5000-3p/FBXW7 axis.

Background:

Patient identification is an important step for advance care planning (ACP) discussions.

Background:

Facilitation is an effective approach for helping practices implement sustainable evidence-based practice improvements. Few studies examine the facilitation infrastructure and support needed for large-scale dissemination and implementation initiatives.

Introduction:

Understanding patients’ perspectives about their diabetes and what causes those perspectives to shift is critical to building a treatment strategy with the patient and facilitating patient self-management behavior. Key "turning points" can provide crucial opportunities to enact a change in perspective. The goal of this study is to identify "turning points" that have significance to diabetes-related health.

Purpose:

Excess weight gain during pregnancy is at epidemic proportions, and pregnancy complications are also on the rise. We sought to determine whether better weight gain counseling of expectant mothers will improve obstetric outcomes.

Access to services related to reproductive and sexual health is critical to the health of women but has been threatened in recent years. Family physicians are trained to provide a range of women’s health care services and are an essential part of the health care workforce in rural and underserved areas, where access to these services may be limited.

Evaluations of health care–based screening programs for social risks often report that a relatively small proportion of patients screening positive for social risk factors are interested in receiving assistance from their health care teams to address them. The relatively low number of patients who desire assistance is relevant to the growing number of initiatives in US health care settings designed to collect data on and address patients’ social risks. We highlight multiple studies that have found differences between positive risks screens and desire for assistance. We explore possible explanations for those differences—focusing on the fallibility of screening tools as well as patient preferences, priorities, and lived experiences—and the potential implications for health equity.

Family physician researchers continue to provide assistance to improve family medicine care. Commentaries on social determinants of health lead off this issue. Next, we have several papers on successful interventions by clinicians and/or patients to improve diabetes control, and then other provide information on other practice interventions that make a difference in overall care. Drug advertising continues to mislead. There is costly and nonproductive overuse of specific types of care. Herein is also a Scoping Review of possible indices for determining timely initiation of advance care planning. The issue’s clinical reviews on use of transgender care, cervical myelopathy, and inhaled steroids for chronic obstructive pulmonary disease are pertinent, thorough, and timely.

Kathryn Knight

William Joyce and Tobias Wang

Rafael Dalmau

Lucy A. Winder, Stewart A. White, Andreas Nord, Barbara Helm, and Dominic J. McCafferty

During winter at temperate and high latitudes, the low ambient temperatures, limited food supplies and short foraging periods mean small passerines show behavioural, morphological and physiological adaptations to reduce the risk of facing energy shortages. Peripheral tissues vasoconstrict in low ambient temperatures to reduce heat loss and cold injury. Peripheral vasoconstriction has been observed with food restriction in captivity but has yet to be explored in free-ranging animals. We experimentally food restricted both wild and captive great tits (Parus major) during winter months and measured surface temperatures of the bill and eye region using thermal imaging, to investigate whether birds show rapid local heterothermic responses, which may reduce their thermoregulatory costs when facing a perceived imminent food shortage. Our results of a continuously filmed wild population showed that bill temperature was immediately reduced in response to food restriction compared with when food was available ad libitum, an apparent autonomic response. Such immediacy implies a ‘pre-emptive’ response before the bird experiences any shortfalls in energy reserves. We also demonstrate temporal variation in vasoconstriction of the bill, with bill temperature gradually rising throughout the food restriction after the initial drop. Eye-region temperature in the wild birds remained at similar levels throughout food restriction compared with unrestricted birds, possibly reflecting the need to maintain steady circulation to the central nervous and visual systems. Our findings provide evidence that birds selectively allow the bill to cool when a predictable food supply is suddenly disrupted, probably as a means of minimising depletion of body reserves for a perceived future shortage in energy.

Fredrik Andreasson, Arne Hegemann, Andreas Nord, and Jan-Ake Nilsson

The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared with unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction.

Andreas Nord, Arne Hegemann, and Lars P. Folkow

Animals in seasonal environments must prudently manage energy expenditure to survive the winter. This may be achieved through reductions in the allocation of energy for various purposes (e.g. thermoregulation, locomotion, etc.). We studied whether such trade-offs also include suppression of the innate immune response, by subjecting captive male Svalbard ptarmigan (Lagopus muta hyperborea) to bacterial lipopolysaccharide (LPS) during exposure to either mild temperature (0°C) or cold snaps (acute exposure to –20°C), in constant winter darkness when birds were in energy-conserving mode, and in constant daylight in spring. The innate immune response was mostly unaffected by temperature. However, energy expenditure was below baseline when birds were immune challenged in winter, but significantly above baseline in spring. This suggests that the energetic component of the innate immune response was reduced in winter, possibly contributing to energy conservation. Immunological parameters decreased (agglutination, lysis, bacteriostatic capacity) or did not change (haptoglobin/PIT54) after the challenge, and behavioural modifications (anorexia, mass loss) were lengthy (9 days). While we did not study the mechanisms explaining these weak, or slow, responses, it is tempting to speculate they may reflect the consequences of having evolved in an environment where pathogen transmission rate is presumably low for most of the year. This is an important consideration if climate change and increased exploitation of the Arctic would alter pathogen communities at a pace outwith counter-adaption in wildlife.

Ana Gabriela Jimenez, Emily Cornelius Ruhs, Kailey J. Tobin, Katie N. Anderson, Audrey Le Pogam, Lyette Regimbald, and Francois Vezina

Seasonal changes in maximal thermogenic capacity (M_sum) in wild black-capped chickadees suggests that adjustments in metabolic performance are slow and begin to take place before winter peaks. However, when mean minimal ambient temperature (T_a) reaches –10°C, the chickadee phenotype appears to provide enough spare capacity to endure days with colder T_a, down to –20°C or below. This suggests that birds could also maintain a higher antioxidant capacity as part of their cold-acclimated phenotype to deal with sudden decreases in temperature. Here, we tested how environmental mismatch affected oxidative stress by comparing cold-acclimated (–5°C) and transition (20°C) phenotypes in chickadees exposed to an acute 15°C drop in temperature with that of control individuals. We measured superoxide dismutase, catalase and glutathione peroxidase activities, as well as lipid peroxidation damage and antioxidant scavenging capacity in pectoralis muscle, brain, intestine and liver. We generally found differences between seasonal phenotypes and across tissues, but no differences with respect to an acute cold drop treatment. Our data suggest oxidative stress is closely matched to whole-animal physiology in cold-acclimated birds compared with transition birds, implying that changes to the oxidative stress system happen slowly.

Fredrik Christiansen, Kate R. Sprogis, Jasmin Gross, Juliana Castrillon, Hunter A. Warick, Eva Leunissen, and Susan Bengtson Nash

An animal's body condition provides valuable information for ecophysiological studies, and is an important measure of fitness in population monitoring and conservation. While both the external body shape of an animal and its internal tissues (i.e. fat content) can be used as a measure of body condition, the relationship between the two is not always linear. We compared the morphological body condition (external metric obtained through aerial photogrammetry) of migrating humpback whales (Megaptera novaeangliae) with their outer blubber lipid concentration (internal metric obtained through blubber biopsy sampling) off the coast of south-west Australia early and late in the breeding season (spanning ~4.5 months). The external body condition index of juvenile and adult humpback whales decreased by 26.9 (from 18.8% to –8.1%) and 12.0 percentage points (from 8.6% to –3.4%), respectively, between the early and late phase. In contrast, we found no intra-seasonal change in blubber lipid concentration, and no difference between reproductive classes (juveniles, adults and lactating females); however, the small sample size prevented us from effectively testing these effects. Importantly, however, in the 33 animals for which paired metrics were obtained, we found no correlation between the morphometric body condition index and the blubber lipid concentration of individual whales. The lack of a linear relationship suggests that changes in outer blubber lipid concentration do not reflect external changes in body shape, thus limiting the utility of outer blubber lipid reserves for individual body condition evaluation. The wider spectrum of change in body morphometry captured with aerial photogrammetry supports the use of body morphometry as a reliable and well-tested method.

Zhi-Jun Zhao, Davina Derous, Abby Gerrard, Jing Wen, Xue Liu, Song Tan, Catherine Hambly, and John R. Speakman

Lactating mice increase food intake 4- to 5-fold, reaching an asymptote in late lactation. A key question is whether this asymptote reflects a physiological constraint, or a maternal investment strategy (a ‘restraint’). We exposed lactating mice to periods of food restriction, hypothesizing that if the limit reflected restraint, they would compensate by breaching the asymptote when refeeding. In contrast, if it was a constraint, they would by definition be unable to increase their intake on refeeding days. Using isotope methods, we found that during food restriction, the females shut down milk production, impacting offspring growth. During refeeding, food intake and milk production rose again, but not significantly above unrestricted controls. These data provide strong evidence that asymptotic intake in lactation reflects a physiological/physical constraint, rather than restraint. Because hypothalamic neuropeptide Y (Npy) was upregulated under both states of restriction, this suggests the constraint is not imposed by limits in the capacity to upregulate hunger signalling (the saturated neural capacity hypothesis). Understanding the genetic basis of the constraint will be a key future goal and will provide us additional information on the nature of the constraining factors on reproductive output, and their potential links to life history strategies.

Karen L. Carleton, Daniel Escobar-Camacho, Sara M. Stieb, Fabio Cortesi, and N. Justin Marshall

Among vertebrates, teleost eye diversity exceeds that found in all other groups. Their spectral sensitivities range from ultraviolet to red, and the number of visual pigments varies from 1 to over 40. This variation is correlated with the different ecologies and life histories of fish species, including their variable aquatic habitats: murky lakes, clear oceans, deep seas and turbulent rivers. These ecotopes often change with the season, but fish may also migrate between ecotopes diurnally, seasonally or ontogenetically. To survive in these variable light habitats, fish visual systems have evolved a suite of mechanisms that modulate spectral sensitivities on a range of timescales. These mechanisms include: (1) optical media that filter light, (2) variations in photoreceptor type and size to vary absorbance and sensitivity, and (3) changes in photoreceptor visual pigments to optimize peak sensitivity. The visual pigment changes can result from changes in chromophore or changes to the opsin. Opsin variation results from changes in opsin sequence, opsin expression or co-expression, and opsin gene duplications and losses. Here, we review visual diversity in a number of teleost groups where the structural and molecular mechanisms underlying their spectral sensitivities have been relatively well determined. Although we document considerable variability, this alone does not imply functional difference per se. We therefore highlight the need for more studies that examine species with known sensitivity differences, emphasizing behavioral experiments to test whether such differences actually matter in the execution of visual tasks that are relevant to the fish.

Samantha M. Logan, Kama E. Szereszewski, Nigel C. Bennett, Daniel W. Hart, Barry van Jaarsveld, Matthew E. Pamenter, and Kenneth B. Storey

Mole-rats are champions of self-preservation, with increased longevity compared to other rodents their size, strong antioxidant capabilities, and specialized defenses against endogenous oxidative stress. However, how the brains of these subterranean mammals handle acute in vivo hypoxia is poorly understood. This study is the first to examine the molecular response to low oxygen in six different species of hypoxia-tolerant mole-rats from sub-Saharan Africa. Protein carbonylation, a known marker of DNA damage (hydroxy-2’-deoxyguanosine), and antioxidant capacity did not change following hypoxia but HIF-1 protein levels increased significantly in the brains of two species. Nearly 30 miRNAs known to play roles in hypoxia-tolerance were differentially regulated in a species-specific manner. The miRNAs exhibiting the strongest response to low oxygen stress inhibit apoptosis and regulate neuroinflammation, likely providing neuroprotection. A principal component analysis using a subset of the molecular targets assessed herein revealed differences between control and hypoxic groups for two solitary species (Georychus capensis and Bathyergus suillus), which are ecologically adapted to a normoxic environment, suggesting a heightened sensitivity to hypoxia relative to species that may experience hypoxia more regularly in nature. By contrast, all molecular data were included in the PCA to detect a difference between control and hypoxic populations of eusocial Heterocephalus glaber, indicating they may require many lower-fold changes in signaling pathways to adapt to low oxygen settings. Finally, none of the Cryptomys hottentotus subspecies showed a statistical difference between control and hypoxic groups, presumably due to hypoxia-tolerance derived from environmental pressures associated with a subterranean and social lifestyle.

Christopher T. Richards and Enrico A. Eberhard

Muscle force-length dynamics are governed by intrinsic contractile properties, motor stimulation and mechanical load. Although intrinsic properties are well-characterised, physiologists lack in vitro instrumentation accounting for combined effects of limb inertia, musculoskeletal architecture and contractile dynamics. We introduce in vitro virtual-reality (in vitro-VR) which enables in vitro muscle tissue to drive a musculoskeletal jumping simulation. In hardware, muscle force from a frog plantaris was transmitted to a software model where joint torques, inertia and ground reaction forces were computed to advance the simulation at 1 kHz. To close the loop, simulated muscle strain was returned to update in vitro length. We manipulated 1) stimulation timing and, 2) the virtual muscle's anatomical origin. This influenced interactions among muscular, inertial, gravitational and contact forces dictating limb kinematics and jump performance. We propose that in vitro-VR can be used to illustrate how neuromuscular control and musculoskeletal anatomy influence muscle dynamics and biomechanical performance.

Krishnamoorthy Krishnan, Asif Shahriar Nafi, Roi Gurka, and Roi Holzman

Fish larvae are the smallest self-sustaining vertebrates. As such, they face multiple challenges that stem from their minute size, and from the hydrodynamic regime in which they dwell. This regime, of intermediate Reynolds numbers, was shown to affect the swimming of larval fish and impede their ability to capture prey. Prey capture is impeded because smaller larvae produce weaker suction flows, exerting weaker forces on the prey. Previous observations on feeding larvae also showed prey exiting the mouth after initially entering it (hereafter "in-and-out"), although the mechanism causing such failures had been unclear. In this study, we used numerical simulations to investigate the hydrodynamic mechanisms responsible for the failure to feed caused by this in-and-out prey movement. Detailed kinematics of the expanding mouth during prey capture by larval Sparus aurata were used to parameterize age-specific numerical models of the flows inside the mouth. These models revealed that for small larvae which expand their mouth slowly, fluid entering the mouth cavity is expelled through the mouth before it is closed, resulting in flow reversal at the orifice. This relative efflux of water through the mouth was >8% of the influx through the mouth for younger ages. However similar effluxes were found when we simulated slow strikes by larger fish. The simulations can explain the observations of larval fish failing to fish due to the in-and-out movement of the prey. These results further highlight the importance of transporting the prey from the gape deeper into the mouth cavity in determining suction-feeding success.

Rohini Singh and Timothy A. Linksvayer

Wolbachia is a widespread group of maternally-transmitted endosymbiotic bacteria that often manipulates the reproductive strategy and life history of its hosts to favor its own transmission. Wolbachia mediated phenotypic effects are well characterized in solitary hosts, but effects in social hosts are unclear. The invasive pharaoh ant, Monomorium pharaonis, shows natural variation in Wolbachia infection between colonies and can be readily bred under laboratory conditions. We previously showed that Wolbachia-infected pharaoh ant colonies had more queen-biased sex ratios than uninfected colonies, which is expected to favor the spread of maternally-transmitted Wolbachia. Here, we further characterize the effects of Wolbachia on the short- and longer-term reproductive and life history traits of pharaoh ant colonies. First, we characterized the reproductive differences between naturally infected and uninfected colonies at three discrete time points and found that infected colonies had higher reproductive investment (i.e. infected colonies produced more new queens), particularly when existing colony queens were three months old. Next, we compared the long-term growth and reproduction dynamics of infected and uninfected colonies across their whole life cycle. Infected colonies had increased colony-level growth and early colony reproduction, resulting in a shorter colony life cycle, when compared to uninfected colonies.

Meike Stumpp, Inga Petersen, Femke Thoben, Jia-Jiun Yan, Matthias Leippe, and Marian Y. Hu

Larval stages of the abulacraria superphylum including echinoderms and hemichordates have highly alkaline midguts. To date the reason for the evolution of such extreme pH conditions in the gut of these organisms remains unknown. Here, we test the hypothesis that analogous to the acidic stomachs of vertebrates, these alkaline conditions may represent a first defensive barrier to protect from environmental pathogens.

pH-optimum curves for five different species of marine bacteria demonstrated a rapid decrease in proliferation rates by 50-60% between pH 8.5 and 9.5. Using the marine bacterium Vibrio diazotrophicus which elicits a coordinated immune response in the sea urchin larva of Strongylocentrotus purpuratus, we studied the physiological responses of the midgut pH regulatory machinery to this pathogen. Gastroscopic microelectrode measurements demonstrate a stimulation of midgut alkalization upon infection with V. diazotrophicus accompanied by an upregulation of acid-base transporter transcripts of the midgut. Pharmacological inhibition of midgut alkalization resulted in an increased mortality rate of larvae during Vibrio infection. Reductions in seawater pH resembling ocean acidification (OA) conditions lead to moderate reductions in midgut alkalization. However, these reductions in midgut pH do not affect the immune response and resilience of sea urchin larvae to a Vibrio infection under OA conditions.

Our study addressed the evolutionary benefits of the alkaline midgut of ambulacraria larval stages. The data indicate that alkaline conditions in the gut may serve as a first defensive barrier against environmental pathogens and that this mechanism can compensate for changes in seawater pH.

Brian K. McNab and Kerry A. Weston

The thermal physiology of the endangered New Zealand rockwren (Xenicus gilviventris) is examined. It is a member of the Acanthisittidae, a family unique to New Zealand. This family, derived from Gondwana, is thought to be the sister taxon to all other passerines. Rockwrens permanently reside above the climatic timberline at altitudes from 1,000 to 2,900 meters in the mountains of South Island. They feed on invertebrates and in winter face ambient temperatures far below freezing and deep deposits of snow. Their body temperature and rate of metabolism are highly variable. Rockwrens regulate body temperature at ca. 36.4°C, which in one individual decreased to 33.1°C at an ambient temperature of 9.4°C. Its rate of metabolism decreased by 30%; body temperature spontaneously returned to 36°C. The rate of metabolism in a second individual twice decreased by 35%, nearly to the basal rate expected from mass without a decrease in body temperature. The New Zealand rockwren's food habits, entrance into torpor, and continuous residence in a thermally demanding environment suggest that it may hibernate. For that conclusion to be accepted, evidence of its use of torpor for extended periods is required. Those data are not presently available. Acanthisittids are distinguished from other passerines by the combination of their permanent temperate distribution, thermal flexibility, and a propensity to evolve a flightless condition. These characteristics may principally reflect their geographical isolation in a temperate environment isolated from Gondwana for 82 million years in the absence of mammalian predators.

Yi Huang, Jazmin Osorio Mendoza, Catherine Hambly, Baoguo Li, Zengguang Jin, Li Li, Moshen Madizi, Sumei Hu, and John R. Speakman

The heat dissipation limit theory predicts lactating female mice consuming diets with lower specific dynamic action (SDA) should have enhanced lactation performance. Dietary fat has lower SDA than other macronutrients. Here we tested the effects of graded dietary fat levels on lactating Swiss mice. We fed females five diets varying in fat content from 8.3 to 66.6%. Offspring of mothers fed diets of 41.7% fat and above were heavier and fatter at weaning compared to those of 8.3% and 25% fat diets. Mice on dietary fat contents of 41.7% and above had greater metabolizable energy intake at peak lactation (8.3%: 229.4±39.6, 25%: 278.8±25.8, 41.7%: 359.6±51.5, 58.3%: 353.7±43.6, 66.6%: 346±44.7 kJ day^–1), lower daily energy expenditure (8.3%: 128.5±16, 25%: 131.6±8.4, 41.7%: 124.4±10.8, 58.3%: 115.1±10.5, 66.6%: 111.2±11.5 kJ day^–1) and thus delivered more milk energy to their offspring (8.3%: 100.8±27.3, 25%: 147.2±25.1, 41.7%: 225.1±49.6, 58.3%: 238.6±40.1, 66.6%: 234.8±41.1 kJ day^–1). Milk fat content (%) was unrelated to dietary fat content, indicating females on higher fat diets (> 41.7%) produced more rather than richer milk. Mothers consuming diets with 41.7% fat or above enhanced their lactation performance compared to those on 25% or less, probably by diverting dietary fat directly into the milk, thereby avoiding the costs of lipogenesis. At dietary fat contents above 41.7% they were either unable to transfer more dietary fat to the milk, or they chose not to do so, potentially because of a lack of benefit to the offspring that were increasingly fatter as maternal dietary fat increased.

Imants G. Priede, Rhoderick W. Burgass, Manolis Mandalakis, Apostolos Spyros, Petros Gikas, Finlay Burns, and Jim Drewery

Whereas upper ocean pelagic sharks are negatively buoyant and must swim continuously to generate lift from their fins, deep-sea sharks float or swim slowly buoyed up by large volumes of low-density oils in their livers. Investigation of the Pressure, Volume, Temperature (PVT) relationships for liver oils of 10 species of deep-sea Chondrichthyes shows that the density difference between oil and seawater, remains almost constant with pressure down to full ocean depth (11 km, 1100 bar); theoretically providing buoyancy far beyond the maximum depth of occurrence (3700 m) of sharks. However, , does change significantly with temperature and we show that the combined effects of pressure and temperature can decrease buoyancy of oil by up to 10% between the surface and 3500 m depth across interfaces between warm southern and cold polar waters in the Rockall Trough in the NE Atlantic. This increases drag more than 10 fold compared with neutral buoyancy during horizontal slow swimming (0.1 m s^–1) but the effect becomes negligible at high speeds. Chondrichthyes generally experience positive buoyancy change during ascent and negative buoyancy change during descent but contrary effects can occur at interfaces between waters of different densities. During normal vertical migrations buoyancy changes are small, increasing slow-speed drag by no more than 2–3 fold. Equations and tables of density, pressure and temperature are provided for squalene and liver oils of Chimaeriformes (Harriotta raleighana, Chimaera monstrosa, Chimaera monstrosa), Squaliformes (Centrophorus squamosus, Deania calcea, Centroscymnus coelolepis, Centroscyllium fabricii, Etmopterus spinax) and Carcharhiniformes (Apristurus laurussonii, Galeus murinus).

Daniel J. Tobiansky, Meredith C. Miles, Franz Goller, and Matthew J. Fuxjager

Performance trade-offs can dramatically alter an organism's evolutionary trajectory by making certain phenotypic outcomes unattainable. Understanding how these trade-offs arise from an animal's design is therefore an important goal of biology. To explore this topic, we study how androgenic hormones, which regulate skeletal muscle function, influence performance trade-offs relevant to different components of complex reproductive behaviour. We conduct this work in golden-collared manakins (Manacus vitellinus), a Neotropical bird in which males court females by rapidly snapping their wings together above their back. Androgens help mediate the snap displays by radically increasing the twitch speed of a dorsal wing muscle [scapulohumeralis caudalis (SH)], which actuates the bird's wing-snap. Through hormone manipulations and in situ muscle recordings, we test how these positive effects on SH speed influence trade-offs with endurance. Indeed, this trait impacts the display by shaping signal length. We find that androgen-dependent increases in SH speed incur a cost to endurance, particularly when this muscle performs at its functional limits. Moreover, when behavioural data are overlaid on our muscle recordings, displaying animals appear to balance display speed with fatigue-induced muscle fusion (physiological tetanus) to generate the fastest possible signal while maintaining an appropriate signal duration. Our results point to androgenic hormone action as a functional trigger of trade-offs in sexual performance—they enhance one element of a courtship display, but in doing so, impede another.

Annebelle C. M. Kok, Lisette van Kolfshoten, James A. Campbell, Alexander M. von Benda-Beckmann, Patrick J. O. Miller, Hans Slabbekoorn, and Fleur Visser

Group-living animals must communicate to stay in contact. In long-finned pilot whales, there is a trade-off between the benefits of foraging individually at depth and the formation of tight social groups at the surface. Using theoretical modelling and empirical data of tagged pairs within a group, we examined the potential of pilot whale social calls to reach dispersed group-members during foraging periods. Both theoretical predictions and empirical data of tag pairs showed a potential for communication between diving and non-diving group members over separation distances up to at least 385 m (empirical) and 1800 m (theoretical). These distances are at or exceeding pilot whale dive depths recorded across populations. Call characteristics and environmental characteristics were analysed to investigate determinants of call detectability. Longer calls with a higher sound pressure level (SPL) that were received in a quieter environment were more often detected than their shorter, lower SPL counterparts within a noisier environment. In a noisier environment, calls were louder and had a lower peak frequency, indicating mechanisms for coping with varying conditions. However, the vulnerability of pilot whales to anthropogenic noise is still of concern as the ability to cope with increasing background noise may be limited. Our study shows that combining propagation modelling and actual tag recordings provides new insights into the communicative potential for social calls in orientation and reunion with group members for deep-diving pilot whales.

Thomas J. Lisney, Shaun P. Collin, and Jennifer L. Kelley

Ecological factors such as spatial habitat complexity and diet can explain variation in visual morphology, but few studies have sought to determine whether visual specialisation can occur among populations of the same species. We used a small Australian freshwater fish (the western rainbowfish, Melanotaenia australis) to determine whether populations showed variation in eye size and eye position, and whether this variation could be explained by environmental (light availability, turbidity) and ecological (predation risk, habitat complexity, invertebrate abundance) variables. We investigated three aspects of eye morphology, (1) eye size relative to body size, (2) pupil size relative to eye size, and (3) eye position in the head, for fish collected from 14 sites in a major river catchment in northwest Western Australia. We found significant variation among populations in all three measures of eye morphology, but no effect of sex on eye size or eye position. Variation in eye diameter and eye position was best explained by the level of habitat complexity. Specifically, fish occurring in habitats with low complexity (i.e. open water) tended to have smaller, more dorsally-located eyes, than those occurring in more complex habitats (i.e. vegetation present). The size of the pupil relative to the size of the eye was most influenced by the presence of surrounding rock formations; fish living in gorge habitats had significantly smaller pupils (relative to eye size) than those occupying semi-gorge sites or open habitats. Our findings reveal that different ecological and environmental factors contribute to habitat-specific visual specialisations within a species.

Rachel L. Sutcliffe, Shaorong Li, Matthew J. H. Gilbert, Patricia M. Schulte, Kristi M. Miller, and Anthony P. Farrell

We examined cardiac pacemaker rate resetting in rainbow trout following a reciprocal temperature transfer. In the original experiment, performed in winter, 4°C-acclimated fish transferred to 12°C reset intrinsic heart rate after just 1 h (from 56.8±1.2 to 50.8±1.5 bpm); 12°C-acclimated fish transferred to 4°C reset intrinsic heart rate after 8 h (from 33.4±0.7 to 37.7±1.2 bpm). However, in a replicate experiment, performed in the summer using a different brood year, intrinsic heart rate was not reset, even after 10 weeks at a new temperature. Using this serendipitous opportunity, we compared mRNA expression changes of a suite of proteins in sinoatrial node (SAN), atrial and ventricular tissues after both 1 h and longer than 3 weeks for both experimental acclimation groups to identify those changes only associated with pacemaker rate resetting. Of the changes in mRNA expression occurring after more than 3 weeks of warm acclimation and associated with pacemaker rate resetting, we observed downregulation of NKA α1c in the atrium and ventricle, and upregulation of HCN1 in the ventricle. However, in the SAN there were no mRNA expression changes unique to the fish with pacemaker rate resetting after either 1 h or 3 weeks of warm acclimation. Thus, despite identifying changes in mRNA expression of contractile cardiac tissues, there was absence of changes in mRNA expression directly involved with the initial, rapid pacemaker rate resetting with warm acclimation. Importantly, pacemaker rate resetting with thermal acclimation does not always occur in rainbow trout.

Jing Wen, Tingbei Bo, Xueying Zhang, Zuoxin Wang, and Dehua Wang

Ambient temperature and food composition can affect energy metabolism of the host. Thermal transient receptor potential (thermo-TRPs) ion channels can detect temperature signals and are involved in the regulation of thermogenesis and energy homeostasis. Further, the gut microbiota has also been implicated in thermogenesis and obesity. In the present study, we tested the hypothesis that thermo-TRPs and gut microbiota are involved in reducing diet-induced obesity (DIO) during low temperature exposure. C57BL/6J mice in obese (body mass gain >45%), lean (body mass gain <15%), and control (body mass gain<1%) groups were exposed to high (23±1°C) or low (4±1°C) ambient temperature for 28 days. Our data showed that low temperature exposure attenuated DIO, but enhanced brown adipose tissue (BAT) thermogenesis. Low temperature exposure also resulted in increased norepinephrine (NE) concentrations in the hypothalamus, decreased TRP melastatin 8 (TRPM8) expression in the small intestine, and altered composition and diversity of gut microbiota. In DIO mice, there was a decrease in overall energy intake along with a reduction in TRP ankyrin 1 (TRPA1) expression and an increase in NE concentration in the small intestine. DIO mice also showed increases in Oscillospira, [Ruminococcus], Lactococcus, and Christensenella and decreases in Prevotella, Odoribacter, and Lactobacillus at the genus level in fecal samples. Together, our data suggest that thermos-TRPs and gut microbiota are involved in thermogenesis and energy metabolism during low temperature exposure in DIO mice.

Itsumi Nakamura, Rui Matsumoto, and Katsufumi Sato

It is generally assumed that the body temperature of large animals is less likely to change due to their large body size, resulting in a high thermal inertia and a smaller surface area to volume ratio. The goal of this study was to investigate the stability of body temperature in large fish using data from field experiments. We measured the muscle temperatures of free-ranging whale sharks (Rhincodon typus), the largest extant fish globally, and investigated their ectothermic physiology and the stability of their body temperatures. The measured muscle temperature of the whale sharks changed substantially more slowly than the water temperature fluctuations associated with vertical movements, and the whole-body heat-transfer coefficients (HTC) of whale sharks estimated using heat-budget models were lower than those of any other fish species measured to date. The heat-budget models also showed that internal heat production does not contribute to changes in muscle temperature. A comparative analysis showed that the HTC at cooling in various fish species including both ectothermic and endothermic species ranging from 10^–4 to 10³ kg was proportional to body mass^–0.63. This allometry was present regardless of whether the fish were ectothermic or endothermic, and was an extension of the relationship observed in previous studies on small fish. Thus, large fish have the advantage of body temperature stability while moving in environments with large temperature variations. Our results suggest that the large body size of whale sharks aids in preventing a decrease in body temperature during deep excursions to more than 1000 m depths without high metabolic costs of producing heat.

David E. Cade, J. Jacob Levenson, Robert Cooper, Rafael de la Parra, D. Harry Webb, and Alistair D. M. Dove

Whale sharks (Rhincodon typus Smith 1828) – the largest extant fish species – reside in tropical environments, making them an exception to the general rule that animal size increases with latitude. How this largest fish thrives in tropical environments that promote high metabolism but support less robust zooplankton communities has not been sufficiently explained. We used open-source inertial measurement units (IMU) to log 397 hours of whale shark behavior in Yucatan, Mexico, at a site of both active feeding and intense wildlife tourism. Here we show that the strategies employed by whale sharks to compensate for the increased drag of an open mouth are similar to ram-feeders five orders of magnitude smaller and one order of magnitude larger. Presumed feeding constituted 20% of the total time budget of four sharks, with individual feeding bouts lasting up to 11 consecutive hrs. Compared to normal, sub-surface swimming, three sharks increased their stroke rate and amplitude while surface feeding, while one shark that fed at depth did not demonstrate a greatly increased energetic cost. Additionally, based on time-depth budgets, we estimate that aerial surveys of shark populations should consider including a correction factor of 3 to account for the proportion of daylight hours that sharks are not visible at the surface. With foraging bouts generally lasting several hours, interruptions to foraging during critical feeding periods may represent substantial energetic costs to these endangered species, and this study presents baseline data from which management decisions affecting tourist interactions with whale sharks may be made.

Jack Nguyen and Meir M. Barak

Cortical bone remodeling is an ongoing process triggered by microdamage, where osteoclasts resorb existing bone and osteoblasts deposit new bone in the form of secondary osteons (Haversian systems). Previous studies revealed regional variance in Haversian systems structure and possibly material, between opposite cortices of the same bone. As bone mechanical properties depend on tissue structure and material, it is predicted that bone mechanical properties will vary in accordance with structural and material regional heterogeneity. To test this hypothesis, we analyzed the structure, mineral content and compressive stiffness of secondary bone from the cranial and caudal cortices of the white-tailed deer proximal humerus. We found significantly larger Haversian systems and canals in the cranial cortex but no significant difference in mineral content between the two cortices. Accordingly, we found no difference in compressive stiffness between the two cortices and thus our working hypothesis was rejected. Seeing that the deer humerus is curved and thus likely subjected to bending during habitual locomotion, we expect that similar to other curved long bones, the cranial cortex of the deer humerus is likely subjected primarily to tensile strains and the caudal cortex is likely subject primarily to compressive strains. Consequently, our results suggest that strain magnitude (larger in compression) and sign (compression vs. tension) affect differently the osteoclasts and osteoblasts in the BMU. Our results further suggest that osteoclasts are inhibited in regions of high compressive strains (creating smaller Haversian systems) while osteoblasts’ osteoid deposition and mineralization is not affected by strain magnitude and sign.

Flemming Dahlke, Magnus Lucassen, Ulf Bickmeyer, Sylke Wohlrab, Velmurugu Puvanendran, Atle Mortensen, Melissa Chierici, Hans-Otto Pörtner, and Daniela Storch

The vulnerability of fish embryos and larvae to environmental factors is often attributed to a lack of adult-like organ systems (gills) and thus insufficient homeostatic capacity. However, experimental data supporting this hypothesis are scarce. Here, by using Atlantic cod (Gadus morhua) as a model, the relationship between embryo vulnerability (to projected ocean acidification and warming) and homeostatic capacity was explored through parallel analyses of stage-specific mortality and in vitro activity and expression of major ion pumps (ATP-Synthase, Na⁺/K⁺-ATPase, H⁺-ATPase) and co-transporters (NBC1, NKCC1). Immunolocalization of these transporters was used to study ionocyte morphology in newly-hatched larvae. Treatment-related embryo mortality until hatch (+20% due to acidification and warming) occurred primarily during an early period (gastrulation) characterized by extremely low ion transport capacities. Thereafter, embryo mortality decreased in parallel with an exponential increase in activity and expression of all investigated ion transporters. Significant changes in transporter activity and expression in response to acidification (+15% activity) and warming (-30% expression) indicate some potential for short-term acclimatization, although likely associated with energetic trade-offs. Interestingly, whole-larvae enzyme capacities (supported by abundant epidermal ionocytes) reached levels similar to those previously measured in gill tissue of adult cod, suggesting that early-life stages without functional gills are better equipped in terms of ion homeostasis than previously thought. This study implies that the gastrulation period represents a critical transition from inherited (maternal) defenses to active homeostatic regulation, which facilitates enhanced resilience of later stages to environmental factors.

Maria Stager, Nathan R. Senner, Bret W. Tobalske, and Zachary A. Cheviron

Flexibility in heat generation and dissipation mechanisms provides endotherms the ability to match their thermoregulatory strategy with external demands. However, the degree to which these two mechanisms account for seasonal changes in body temperature regulation is little explored. Here we present novel data on the regulation of avian body temperature to investigate how birds alter mechanisms of heat production and heat conservation to deal with variation in ambient conditions. We subjected Dark-eyed Juncos (Junco hyemalis) to chronic cold acclimations of varying duration and subsequently quantified their metabolic rates, thermal conductance, and ability to maintain normothermia. Cold-acclimated birds adjusted traits related to both heat generation (increased summit metabolic rate) and heat conservation (decreased conductance) to improve their body temperature regulation. Increases in summit metabolic rate occurred rapidly, but plateaued after one week of cold exposure. In contrast, changes to conductance occurred only after nine weeks of cold exposure. Thus, the ability to maintain body temperature continued to improve throughout the experiment, but the mechanisms underlying this improvement changed through time. Our results demonstrate the ability of birds to adjust thermoregulatory strategies in response to thermal cues and reveal that birds may combine multiple responses to meet the specific demands of their environments.

Christine Elizabeth Cooper, Laura Leilani Hurley, Pierre Deviche, and Simon Charles Griffith

Desert birds inhabit hot, dry environments that are becoming hotter and drier as a consequence of climate change. Extreme weather such as heatwaves can cause mass-mortality events that may significantly impact populations and species. There are currently insufficient data concerning physiological plasticity to inform models of species’ response to extreme events and develop mitigation strategies. Consequently, we examine here the physiological plasticity of a small desert bird in response to hot (mean maximum ambient temperature=42.7°C) and cooler (mean maximum ambient temperature=31.4°C) periods during a single Austral summer. We measured body mass, metabolic rate, evaporative water loss, and body temperature, along with blood parameters (corticosterone, glucose, and uric acid) of wild zebra finches (Taeniopygia guttata; Gould 1837) to assess their physiological state and determine the mechanisms by which they respond to heatwaves. Hot days were not significant stressors; they did not result in modification of baseline blood parameters or an inability to maintain body mass, provided drinking water was available. During heatwaves, finches shifted their thermoneutral zone to higher temperatures. They reduced metabolic heat production, evaporative water loss and wet thermal conductance, and increased hyperthermia, especially when exposed to high ambient temperature. A consideration of the significant physiological plasticity that we have demonstrated to achieve more favourable heat and water balance is essential for effectively modelling and planning for the impacts of climate change on biodiversity.

Background

Fluid overload in patients undergoing hemodialysis contributes to cardiovascular morbidity and mortality. There is a global trend to lower dialysate sodium with the goal of reducing fluid overload.

Background

After accounting for known risk factors for CKD progression in children, clinical outcomes among children with CKD still vary substantially. Biomarkers of tubular injury (such as KIM-1), repair (such as YKL-40), or inflammation (such as MCP-1, suPAR, TNF receptor-1 [TNFR-1], and TNFR-2) may identify children with CKD at risk for GFR decline.

Background

Water and solute transport across epithelia can occur via the transcellular or paracellular pathways. Tight junctions play a key role in mediating paracellular ion reabsorption in the kidney. In the renal collecting duct, which is a typical absorptive tight epithelium, coordination between transcellular sodium reabsorption and paracellular permeability may prevent the backflow of reabsorbed sodium to the tubular lumen along a steep electrochemical gradient.

Group II introns are mobile genetic elements that perform both self-splicing and intron mobility reactions. These ribozymes are comprised of a catalytic RNA core that binds to an intron-encoded protein (IEP) to form a ribonucleoprotein (RNP) complex. Splicing proceeds through two competing reactions: hydrolysis or branching. Group IIC intron ribozymes have a minimal RNA architecture, and splice almost exclusively through hydrolysis in ribozyme reactions. Addition of the IEP allows the splicing reaction to form branched lariat RNPs capable of intron mobility. Here we examine ribozyme splicing, IEP-dependent splicing, and mobility reactions of a group IIC intron from the thermophilic bacterium Thermoanerobacter italicus (Ta.it.I1). We show that Ta.it.I1 is highly active for ribozyme activity, forming linear hydrolytic intron products. Addition of purified IEP switches activity to the canonical lariat forming splicing reaction. We demonstrate that the Ta.it.I1 group IIC intron coordinates the progression of the forward splicing reaction through a –' interaction between intron domains II and VI. We further show that branched splicing is supported in the absence of the IEP when the –' interaction is mutated. We also investigated the regulation of the two steps of reverse splicing during intron mobility into DNA substrates. Using a fluorescent mobility assay that simultaneously visualizes all steps of intron integration into DNA, we show that completion of reverse splicing is tightly coupled to cDNA synthesis regardless of mutation of the –' interaction.

Glycine riboswitches utilize both single- and tandem-aptamer architectures. In the tandem system, the relative contribution of each aptamer toward gene regulation is not well understood. To dissect these contributions, the effects of 684 single mutants of a tandem ON switch from Bacillus subtilis were characterized for the wild-type construct and binding site mutations that selectively restrict ligand binding to either the first or second aptamer. Despite the structural symmetry of tandem aptamers, the response to these mutations was frequently asymmetrical. Mutations in the first aptamer often significantly weakened the K_1/2, while several mutations in the second aptamer improved the amplitude. These results demonstrate that this ON switch favors ligand binding to the first aptamer. This is in contrast to the tandem OFF switch variant from Vibrio cholerae, which was previously shown to have preferential binding to its second aptamer. A bioinformatic analysis of tandem glycine riboswitches revealed that the two binding pockets are differentially conserved between ON and OFF switches. Altogether, this indicates that tandem ON switch variants preferentially utilize binding to the first aptamer to promote helical switching, while OFF switch variants favor binding to the second aptamer. The data set also revealed a cooperative glycine response when both binding pockets were maximally stabilized with three GC base pairs. This indicates a cooperative response may sometimes be obfuscated by a difference in the affinities of the two aptamers. This conditional cooperativity provides an additional layer of tunability to tandem glycine riboswitches that adds to their versatility as genetic switches.

Transposable elements (TEs) can damage genomes, thus organisms use a variety of mechanisms to repress TE expression. The PIWI–piRNA pathway is a small RNA pathway that represses TE expression in the germline of animals. Here we explore the function of the pathway in the somatic stem cells of Hydra, a long-lived freshwater cnidarian. Hydra have three stem cell populations, all of which express PIWI proteins; endodermal and ectodermal epithelial stem cells (ESCs) are somatic, whereas the interstitial stem cells have germline competence. To study somatic function of the pathway, we isolated piRNAs from Hydra that lack the interstitial lineage and found that these somatic piRNAs map predominantly to TE transcripts and display the conserved sequence signatures typical of germline piRNAs. Three lines of evidence suggest that the PIWI–piRNA pathway represses TEs in Hydra ESCs. First, epithelial knockdown of the Hydra piwi gene hywi resulted in up-regulation of TE expression. Second, degradome sequencing revealed evidence of PIWI-mediated cleavage of TE RNAs in epithelial cells using the ping-pong mechanism. Finally, we demonstrated a direct association between Hywi protein and TE transcripts in epithelial cells using RNA immunoprecipitation. Altogether, our data reveal that the PIWI–piRNA pathway represses TE expression in the somatic cell lineages of Hydra, which we propose contributes to the extreme longevity of the organism. Furthermore, our results, in combination with others, suggest that somatic TE repression is an ancestral function of the PIWI–piRNA pathway.

Relevant publications related to medicinal and toxic aerosols are discussed in this review. Treatment of COPD includes a combination of long-acting bronchodilators and long-acting muscarinic antagonists. A combination of aclidinium bromide and formoterol fumarate was approved in the United States. The combination was superior to its components alone, as well as tiotropium and a salmeterol-fluticasone combination. Increased risk of an asthma exacerbation was reported in children exposed to electronic nicotine delivery systems. A smart inhaler capable of recording inspiratory flow was approved in the United States. The use of as-needed budesonide-formoterol was reported to be superior to scheduled budesonide and as-needed terbutaline for the treatment of adults with mild-to-moderate asthma. A survey among teens with asthma and their caregivers revealed a disagreement in the number of inhaled controller medications the teen was taking. Treatment with inhaled hypertonic saline resulted in a decreased lung clearance index in infants and preschool children with cystic fibrosis. Surgical masks were well tolerated and significantly decreased the burden of aerosolized bacteria generated by coughing in adults with cystic fibrosis. Inhaled liposomal amikacin in addition to guideline-based therapy was reported to be superior to guideline-based therapy alone in achieving negative sputum cultures in adult subjects with Mycobacterium avium complex pulmonary disease. During 2019, lung injury associated to e-cigarette or vaping was reported, including 60 casualties.