Floral organ abscission in Arabidopsis requires the combined activities of three TALE homeodomain transcription factors.

Floral organ abscission is a separation process in which sepals, petals, and stamens detach from the plant at abscission zones. Here, we investigated the collective role of three amino-acid-loop-extension (TALE) homeobox genes ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1), KNAT6 (for KNOTTED LIKE from Arabidopsis thaliana) and KNAT2, which form a module that patterns boundaries under the regulation of BLADE-ON-PETIOLE 1 and 2 (BOP1/2) co-activators. These TALE homeodomain transcription factors were shown to maintain boundaries in the flower, functioning as a unit to coordinate the growth, patterning, and activity of abscission zones. Together with BOP1 and BOP2, ATH1 and its partners KNAT6 and KNAT2 collectively contribute to the differentiation of lignified and separation layers of the abscission zone. The genetic interactions of BOP1/2 and ATH1 with INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) were also explored. We showed that BOP1/2 co-activators and ATH1 converge with the IDA signalling pathway to promote KNAT6 and KNAT2 expression in the abscission zone and cell separation. ATH1 acts as a central regulator in floral organ abscission as it controls the expression of other TALE genes in abscission zone cells.

An unexpected new red-bellied Stumpffia (Microhylidae) from forest fragments in central Madagascar highlights remaining cryptic diversity.

The Madagascan endemic subfamily Cophylinae in the family Microhylidae, is an example of a taxonomic group for which much is still to be discovered. Indeed, the cophyline frogs present a large portion of Madagascar's cryptic and microendemic amphibian diversity, yet they remain understudied. A new red-bellied species of the microhylid frog genus Stumpffia is described from the central plateau of Madagascar. Visual encounter surveys in Ambohitantely and Anjozorobe in 2019 and 2020 identified this previously unknown Stumpffia species, which closely resembles Stumpffiakibomena known from Andasibe in the east. Stumpffialynnae sp. nov. adds another species to the red-bellied species complex, differing from S.kibomena by genetic differentiation in the mitochondrial 16S rRNA gene (3.6-3.9%) and distinct nuclear RAG1 haplotypes, as well as strongly by its advertisement call. The new species is known from across Ambohitantely Special Reserve and Anjozorobe Angavo protected area, but is known only from one complete specimen and eight individual tissue samples. Based on the rarity of the species, the small number of locations in which it has been found, and its disappearing forest habitat, its IUCN Red List classification is suggested as "Endangered". This species is the first Stumpffia described from Madagascar's central plateau, highlighting the importance of conserving the remnant forest fragments in this area and the ongoing need to survey and protect this threatened habitat type.

Thoracic weighting of restrained subjects during exhaustion recovery causes loss of lung reserve volume in a model of police arrest.

Restraint asphyxia has been proposed as a mechanism for some arrest-related deaths that occur during or shortly after a suspect is taken into custody. Our analysis of the literature found that prone positioning, weight applied to the back, recovery after simulated pursuit, and restraint position have led to restrictive, but non life-threatening respiratory changes when tested in subsets. However, the combined effects of all four parameters have not been tested together in a single study. We hypothesized that a complete protocol with high-sensitivity instrumentation could improve our understanding of breathing physiology during weighted restraint. We designed an electrical impedance tomography (EIT)-based protocol for this purpose and measured the 3D distribution of ventilation within the thorax. Here, we present the results from a study on 17 human subjects that revealed FRC declines during weighted restrained recovery from exercise for subjects in the restraint postures, but not the control posture. These prolonged FRC declines were consistent with abdominal muscle recruitment to assist the inspiratory muscles, suggesting that subjects in restraint postures have increased work of breathing compared to controls. Upon removal of the weighted load, lung reserve volumes gradually increased for the hands-behind-the-head restraint posture but continued to decrease for subjects in the hands-behind-the-back restraint posture. We discuss the possible role this increased work of breathing may play in restraint asphyxia.

A simple and dynamic thermal gradient device for measuring thermal performance in small ectotherms.

The body temperature of ectothermic animals is heavily dependent on environmental temperature, impacting fitness. Laboratory exposure to favorable and unfavorable temperatures is used to understand these effects, as well as the physiological, biochemical, and molecular underpinnings of variation in thermal performance. Although small ectotherms, like insects, can often be easily reared in large numbers, it can be challenging and expensive to simultaneously create and manipulate several thermal environments in a laboratory setting. Here, we describe the creation and use of a thermal gradient device that can produce a wide range of constant or varying temperatures concurrently. Conservatively, this system as designed can operate between -6 °C and 40 °C. This device is composed of a solid aluminum plate and copper piping, combined with a pair of refrigerated circulators. As a simple proof-of-concept, we completed single experimental runs to produce a low-temperature survival curve for flies (Drosophila melanogaster) and explore the effects of daily thermal cycles of varying amplitude on growth rates of crickets (Gryllodes sigillatus). This approach avoids the use of multiple heating/cooling water or glycol baths or incubators for large-scale assessments of organismal thermal performance. It makes static or dynamic thermal experiments (e.g., creating a thermal performance or survival curves, quantifying responses to fluctuating thermal environments, or monitoring animal behavior across a range of temperatures) easier, faster, and less costly.

Using Electrical Impedance Tomography in an Experimental Model of Weighted Restraint.

One restraint technique used by police and paramedical personnel is to apply weight to a prone subject. There is concern that the weight and posture cause breathing difficulties and that restraint asphyxia could contribute to rare, inexplicable arrest-related deaths. Previous studies on restraint asphyxia have used global measures of breathing, which are less sensitive to ventilation changes than other methods. We present a methodology for monitoring individual adaptations to the conditions present in weighted restraint using electrical impedance tomography, which can image the changing distribution of ventilation over time. Results from a pilot study of seven subjects indicated that loss of lung reserve volume was a common consequence of weighted restraint. Our results imply that in more extreme scenarios in which the full weight of one or more officers is applied to a subject during recovery from strenuous activity, weighted restraint may augment risk to the subject. Finally, subjects in the restraint posture of hands behind their heads on average had larger tidal volumes during recovery than subjects with hands behind their backs or at their sides, suggesting this posture permitted deeper breathing and may be preferred in practice, though further study in a larger population is needed.

Comparison of the nutritional content of the captive and wild diets of the critically endangered mountain chicken frog (Leptodactylus fallax) to improve its captive husbandry.

It is vital to provide appropriate nutrition to maintain healthy populations in conservation breeding programs. Knowledge of the wild diet of a species can be used to inform captive diet formulation. The nutritional content of the wild diet of the critically endangered mountain chicken frog (Leptodactylus fallax) is unknown, like that of most amphibians. In this study, we analyzed the nutritional content of food items that comprise 91% of the wild diet of L. fallax, by dry weight of food items, and all food items offered to captive L. fallax at ZSL London Zoo and Jersey Zoo. We subsequently compared the nutritional content of the wild diet and captive diet at ZSL London Zoo consumed by L. fallax. To the authors' knowledge, this is the first study to directly compare the nutritional content of the wild and captive diets of an anuran amphibian. The captive diet at ZSL London Zoo, without dusting of nutritional supplements, was higher in gross energy and crude fat and lower in ash, calcium and calcium:phosphorus ratio than the wild diet. Most of the food items in the captive diets had a high omega-6:omega-3 fatty acid ratio and in the wild diet had a low omega-6:omega-3 fatty acid ratio. We recommend a combination of modifications to the captive diets to better reflect the nutritional content of the wild diet. Nutritional analysis of captive and wild diets is recommended for other species in conservation breeding programs to improve captive husbandry and ultimately fitness.

Swimming activity and energetic costs of adult lake sturgeon during fishway passage.

Fish migrations through riverine systems can be energetically demanding, and the presence of fishways to facilitate upstream passage can add an additional energetic cost that may directly affect fitness. Successful fishway passage is a function of the ability of fish to select appropriate paths and swimming strategies that do not exceed their swimming capacity. Triaxial accelerometers were used to estimate the energetic expenditure of adult lake sturgeon (Acipenser fulvescens) swimming through a vertical slot fishway, to determine whether individual behaviour or path selection, resulting in differences in cumulative energy use, explain fishway passage success. Most individuals attempted to pass the fishway (n=30/44; 68%), although successful passage only occurred for a subset of those attempting (n=7/30; 23%). High-speed swimming was rarely observed during upstream passage through fishway basins, and was of short duration. Two turning basins delayed passage, subsequently resulting in a higher energetic cost. The rate at which energy was expended did not differ among successful and unsuccessful individuals, although successful sturgeon exhibited higher costs of transport (42.75 versus 25.85 J kg(-1) m(-1)). Energy expenditure metrics were not predictive of successful fishway passage, leading us to conclude that other endogenous or exogenous factors influence passage success. In a practical application of field measurements of energy expenditure, we demonstrate that fishway passage through a structure designed to facilitate migration does result in an energetic loss for lake sturgeon (3249-16,331 J kg(-1)), equivalent to individuals travelling 5.8-28.2 km in a lentic system.

Assessing the global zoo response to the amphibian crisis through 20-year trends in captive collections.

Global amphibian declines are one of the biggest challenges currently facing the conservation community, and captive breeding is one way to address this crisis. Using information from the International Species Information System zoo network, we examined trends in global zoo amphibian holdings across species, zoo region, and species geographical region of origin from 1994 to 2014. These trends were compared before and after the 2004 Global Amphibian Assessment to assess whether any changes occurred and whether zoo amphibian conservation effort had increased. The numbers of globally threatened species (GTS) and their proportional representation in global zoo holdings increased and this rate of increase was significantly greater after 2004. North American, European, and Oceanian GTS were best represented in zoos globally, and proportions of Oceanian GTS held increased the most since 2004. South American and Asian GTS had the lowest proportional representation in zoos. At a regional zoo level, European zoos held the lowest proportions of GTS, and this proportion did not increase after 2004. Since 1994, the number of species held in viable populations has increased, and these species are distributed among more institutions. However, as of 2014, zoos held 6.2% of globally threatened amphibians, a much smaller figure than for other vertebrate groups and one that falls considerably short of the number of species for which ex situ management may be desirable. Although the increased effort zoos have put into amphibian conservation over the past 20 years is encouraging, more focus is needed on ex situ conservation priority species. This includes building expertise and capacity in countries that hold them and tracking existing conservation efforts if the evidence-based approach to amphibian conservation planning at a global level is to be further developed.

How age influences phonotaxis in virgin female Jamaican field crickets (Gryllus assimilis).

Female mating preference can be a dominant force shaping the evolution of sexual signals. However, females rarely have consistent mating preferences throughout their lives. Preference flexibility results from complex interactions of predation risk, social and sexual experience, and age. Because residual reproductive value should theoretically decline with age, older females should not be as choosy as younger females. We explored how age influences phonotaxis towards a standard mate attraction signal using a spherical treadmill (trackball) and a no-choice experimental protocol. Female Jamaican field crickets, Gryllus assimilis, were highly variable in their phonotaxis; age explained up to 64% of this variation. Females 10 days post imaginal eclosion and older oriented toward the mate attraction signal, with 10- and 13-day females exhibiting the greatest movement in the direction of the signal. Our study suggests 10- and 13-day old females would be most responsive when quantifying the preference landscape for G. assimilis sexual signals.

No neural evidence for dynamic auditory tuning of the A1 receptor in the ear of the noctuid moth, Noctua pronuba.

By examining the mechanical properties of the tympanum of the noctuid moth, Noctua pronuba, Windmill et al. (2006) suggested that this insect increases (up-tunes) the frequencies of its best hearing when exposed to high intensity sounds (HIS) resembling the echolocation calls of attacking bats. We tested whether this biophysical phenomenon was encoded in the neural responses of this moth's most sensitive auditory receptor (A1 cell) before and after exposure to HIS. We measured: (1) the number of A1 action potentials (spikes) per stimulus pulse; (2) the proportion of A1 spike periods below that determined to elicit evasive flight maneuvers and, (3) the change in A1 cell firing (spike number, interspike interval, stimulus/spike latency) over a duration of time similar to that in which up-tuning lasts. We observed no significant spiking response changes in the predicted direction to any of the frequencies tested following exposure to HIS and we observed only two of the 24 predicted time-dependent changes to A1 firing. These results indicate that tympanal up-tuning does not result in a change to this moth's auditory frequency sensitivity and we suggest either sensillar resonances or increases in thoracic muscle tension following exposure to HIS as alternative explanations.

Pediatric hospitalists fill varied roles in the care of newborns.

The use of hospitalists in the care of newborns appears to be increasing and may be advantageous for several reasons, including decreased cost, decreased length of stay, increased patient survival, increased availability, and greater experience among hospitalists. Research specific to the use of hospitalists in newborn medicine needs to be done to support this hypothesis. Non-clinical activities such as teaching, developing clinical guidelines, and taking an active role in hospital and academic leadership also may improve education and patient care. It is essential that hospitalists who provide care in nurseries work to smooth the transition to a PCP and not act as a barrier. Relatively speaking, the care provided by hospitalists is most often short-term, and the relationship between infants and their parents with the PCP should begin as soon as possible.

Auditory encoding during the last moment of a moth's life.

The simple auditory system of noctuoid moths has long been a model for anti-predator studies in neuroethology, although these ears have rarely been experimentally stimulated by the sounds they would encounter from naturally attacking bats. We exposed the ears of five noctuoid moth species to the pre-recorded echolocation calls of an attacking bat (Eptesicus fuscus) to observe the acoustic encoding of the receptors at this critical time in their defensive behaviour. The B cell is a non-tympanal receptor common to all moths that has been suggested to respond to sound, but we found no evidence of this and suggest that its acoustic responsiveness is an artifact arising from its proprioceptive function. The A1 cell, the most sensitive tympanal receptor in noctuid and arctiid moths and the only auditory receptor in notodontid moths, encodes the attack calls with a bursting firing pattern to a point approximately 150 ms from when the bat would have captured the moth. At this point, the firing of the A1 cell reduces to a non-bursting pattern with longer inter-spike periods, suggesting that the moth may no longer express the erratic flight used to escape very close bats. This may be simply due to the absence of selection pressure on moths for auditory tracking of bat echolocation calls beyond this point. Alternatively, the reduced firing may be due to the acoustic characteristics of attack calls in the terminal phase and an acoustic maneuver used by the bat to facilitate its capture of the moth. Although the role of less sensitive A2 cell remains uncertain in the evasive flight responses of moths it may act as a trigger in eliciting sound production, a close-range anti-bat behaviour in the tiger moth, Cycnia tenera.