Assessment of oxidant susceptibility of red blood cells in various species based on cell deformability

The present study was designed to investigate the oxidant susceptibility of red blood cells (RBC) from four species (echidna, human, koala, Tasmanian devil) based on changes in cellular deformability. These species were specifically chosen based on differences in lifestyle and/or biology associated with varied levels of oxidative stress. The major focus was the influence of superoxide radicals generated within the cell (phenazine methosulfate, PMS, 50 μM) or in the extracellular medium (xanthine oxidase-hypoxanthine, XO-HX, 0.1 U/ml XO) on RBC deformability at various shear stresses (SS). RBC deformability was assessed by laser-diffraction analysis using a "slit-flow ektacytometer". Both superoxide-generating treatments resulted in significant increases of methemoglobin for all species (p < 0.01), with Tasmanian devil RBC demonstrating the most sensitivity to either treatment. PMS caused impaired RBC deformability for all species, but vast interspecies variations were observed: human and koala cells exhibited a similar sigmoid-like response to SS, short-beaked echidna values were markedly lower and only increased slightly with SS, while Tasmanian devil RBC were extremely rigid. The effect of XO-HX on RBC deformability was less when compared with PMS (i.e., smaller increase in rigidity) with the exception of Tasmanian devil RBC which exhibited essentially no deformation even at the highest SS; Tasmanian devil RBC response to XO-HX was thus comparable to that observed with PMS. Our findings indicate that ektacytometry can be used to determine the oxidant susceptibility of RBC from different species which varies significantly among mammals representing diverse lifestyles and evolutionary histories. These differences in susceptibility are consistent with species-specific discrepancies between observed and allometrically-predicted life spans and are compatible with the oxidant theory of aging.     

Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobranchii: Batoidea: Myliobatiformes) in the Sea of Okhotsk: first record from cold temperate waters

The northernmost record for Chilean devil ray Mobula tarapacana, a circumglobal species that occurs in tropical, subtropical and limited warm temperate waters, is described. An adult female was caught incidentally in the Sea of Okhotsk on 17 September 2011. This specimen is the first confirmed occurrence of devil rays Mobula spp. in cold temperate waters.     

Characterization of major histocompatibility complex class I and class II genes from the Tasmanian devil (<Emphasis Type="Italic">Sarcophilus harrisii</Emphasis>)

The Tasmanian devil (Sarcophilus harrisii) is currently threatened by an emerging wildlife disease, devil facial tumour disease. The disease is decreasing devil numbers dramatically and may lead to the extinction of the species. At present, nothing is known about the immune genes or basic immunology of the devil. In this study, we report the construction of the first genetic library for the Tasmanian devil, a spleen cDNA library, and the isolation of full-length MHC Class I and Class II genes. We describe six unique Class II beta chain sequences from at least three loci, which belong to the marsupial Class II DA gene family. We have isolated 13 unique devil Class I sequences, representing at least seven Class I loci, two of which are most likely non-classical genes. The MHC Class I sequences from the devil have little heterogeneity, indicating recent divergence. The MHC genes described here are most likely involved in antigen presentation and are an important first step for studying MHC diversity and immune response in the devil.     

Production of reactive oxygen species (ROS) by various marine fish species during the larval stage

Previous studies have indicated that the devil stinger produces reactive oxygen species (ROS) during early development from fertilized egg to larva. To determine whether ROS generation is a common feature in marine fish species, we conducted chemiluminescence analysis using ROS specific probe (L012) on larvae of six marine fish species. Marbled rockfish, black rockfish, and devil stinger showed higher levels of chemiluminescence response (CR), whereas the levels of CR of sevenband grouper, tiger puffer, and red seabream were fairly lower. These CRs were inhibited by the addition of superoxide dismutase. Hypersensitive photon-counting microscopic observation of black rockfish suggested that ROS production was concentrated in the head area. Our results suggest that the larvae of these six marine fishes produce ROS to considerably different extents depending on species, and that rockfish species, belonging to ovoviviparous fish, tend to produce much higher levels of ROS especially at the later larval stage.     

Relaxation of risk-sensitive behaviour of prey following disease-induced decline of an apex predator,the Tasmanian devil

Apex predators structure ecosystems through lethal and non-lethal interactions with prey, and their global decline is causing loss of ecological function. Behavioural changes of prey are some of the most rapid responses to predator decline and may act as an early indicator of cascading effects. The Tasmanian devil (Sarcophilus harrisii), an apex predator, is undergoing progressive and extensive population decline, of more than 90% in long-diseased areas, caused by a novel disease. Time since local disease outbreak correlates with devil population declines and thus predation risk. We used hair traps and giving-up densities (GUDs) in food patches to test whether a major prey species of devils, the arboreal common brushtail possum (Trichosurus vulpecula), is responsive to the changing risk of predation when they forage on the ground. Possums spend more time on the ground, discover food patches faster and forage more to a lower GUD with increasing years since disease outbreak and greater devil population decline. Loss of top–down effects of devils with respect to predation risk was evident at 90% devil population decline, with possum behaviour indistinguishable from a devil-free island. Alternative predators may help to maintain risk-sensitive anti-predator behaviours in possums while devil populations remain low.     

Production of reactive oxygen species (ROS) by devil stinger (Inimicus japonicus) during embryogenesis

In aqua-cultural industry, the seed production of devil stinger, a valuable fish in Japan, has not succeeded yet due to the cryptogenic mass mortality. We found that survival rate of the larvae of devil stinger increased by the addition of green tea extract rich in catechin into rearing tank. Generation of reactive oxygen species (ROS) was detected in the embryo of devil stinger by chemiluminescence analysis under the normal growth conditions without addition of specific stimulants. Even in the unfertilized egg, certain level of ROS was detected. ROS were continuously detected during the development from fertilized egg to larva and tended to increase gradually. Observation of embryos and post-hatching larvae with hypersensitive photon-counting microscopy indicated that ROS were produced on the surface of embryo and the head region of larva especially peripheries of eyes. When the embryo proteins were analyzed by immunoblotting using antibody against the human neutrophil cytochrome b558 large subunit (gp91 phox), a main band of approximately 91 kDa was detected, suggesting the presence of NADPH oxidase-like ROS generating system in the embryo of devil stinger. After treatment with streptomycin and penicillin G for 1 day, the level of ROS production in larvae decreased with increase in the survival rate of larvae. Our results suggest that devil stinger has ROS generation system that is already activated at fairly early stage of development before the maturation of usual immune system.     

The characterization of Tasmanian devil Sarcophilius harrisii pelage fibres and their associated lipids

The Tasmanian devil (Sarcophilius harrisii) is the largest living marsupial carnivore left on Earth. In this paper we report the results of the first thorough characterization of the keratin fibres comprising the Tasmanian devil pelage. The fibre's morphology, structure, composition and surface have been investigated. The results have been compared with those of a number of other mammalian species including carnivores and herbivores. The fibres structure was found to be consistent with that expected for a keratin fibre. From the results of the bound lipid analysis it can be concluded that the Tasmanian devil is a typical mammal in which the 21‐carbon atom anteiso branched fatty acid is the predominant bound fatty acid. This is consistent with the Tasmanian devil's position in the mammalian phylogenetic tree. The amino acid analysis places the devil in line with other carnivores. The high cystine and proline content may correlate with the Tasmanian devil's diet which is rich in muscle and collagen proteins.     

Lesser devil rays Mobula cf. hypostoma from Venezuela are almost twice their previously reported maximum size and may be a new sub‐species

Three rays opportunistically obtained near Margarita Island, Venezuela, were identified as lesser devil rays Mobula cf. hypostoma, but their disc widths were between 207 and 230 cm, which is almost double the reported maximum disc width of 120 cm for this species. These morphometric data suggest that lesser devil rays are either larger than previously recognized or that these specimens belong to an unknown sub‐species of Mobula in the Caribbean Sea. Better data are needed to describe the distribution, phenotypic variation and population structure of this poorly known species.     

Patterns of Detection and Capture Are Associated with Cohabiting Predators and Prey

Avoidance behaviour can play an important role in structuring ecosystems but can be difficult to uncover and quantify. Remote cameras have great but as yet unrealized potential to uncover patterns arising from predatory, competitive or other interactions that structure animal communities by detecting species that are active at the same sites and recording their behaviours and times of activity. Here, we use multi-season, two-species occupancy models to test for evidence of interactions between introduced (feral cat Felis catus) and native predator (Tasmanian devil Sarcophilus harrisii) and predator and small mammal (swamp rat Rattus lutreolus velutinus) combinations at baited camera sites in the cool temperate forests of southern Tasmania. In addition, we investigate the capture rates of swamp rats in traps scented with feral cat and devil faecal odours. We observed that one species could reduce the probability of detecting another at a camera site. In particular, feral cats were detected less frequently at camera sites occupied by devils, whereas patterns of swamp rat detection associated with devils or feral cats varied with study site. Captures of swamp rats were not associated with odours on traps, although fewer captures tended to occur in traps scented with the faecal odour of feral cats. The observation that a native carnivorous marsupial, the Tasmanian devil, can suppress the detectability of an introduced eutherian predator, the feral cat, is consistent with a dominant predator – mesopredator relationship. Such a relationship has important implications for the interaction between feral cats and the lower trophic guilds that form their prey, especially if cat activity increases in places where devil populations are declining. More generally, population estimates derived from devices such as remote cameras need to acknowledge the potential for one species to change the detectability of another, and incorporate this in assessments of numbers and survival.     

Rare or just unknown? The occurrence of the giant devil ray (Mobula mobular) in the Adriatic Sea

The presence of the giant devil ray (Mobula mobular) in the Adriatic Sea was evaluated based on new records collected through field research, information from interviews with fisherman and marine biology experts, and a review of existing data from the literature and Internet sources. Presented are 14 new records of 20 individual giant devil rays collected between 2008 and 2011, doubling the number of animals recorded in the Adriatic in the previous 125 years. In total, 28 records of 42 giant devil rays exist for the Adriatic to date. The cryptic life history of the species, its pelagic distribution and lack of systematic data collection have resulted in a low number of historical records. The results suggest that the species is not as rare as previously considered. Occurring mainly in the central and southern Adriatic Sea from early spring to early autumn, its appearance coincides with the general increase in local prey abundance. Interaction with fisheries is identified as a source of potential mortality, and the monitoring of multi‐gear schemes should be carried out at the regional level. Further research on the distribution and abundance of the giant devil ray is crucial for the elaboration of any effective conservation strategy for this endangered species.     

Low MHC class II diversity in the Tasmanian devil (Sarcophilus harrisii)

The largest remaining carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii), is currently under threat of extinction due to a fatal contagious cancer-devil facial tumour disease. Low major histocompatibility complex (MHC) class I diversity is believed to have contributed to the transmission of the tumour allograft through devil populations. Here, we report low MHC class II variability in this species, with DA β chain genes (Saha-DAB1, 2 and 3) exhibiting very limited diversity and the sole α chain gene (Saha-DAA) monomorphic. Three, six and three alleles were found at Saha-DAB1, 2 and 3, respectively, with a predominant allele found at each locus. Heterozygosity at these three loci is low in the eastern population and modestly higher in northwestern individuals. The results are indicative of a selective sweep likely due to an infectious disease resulting in the fixation of selectively favoured alleles and depletion of genetic diversity at devil class II loci. Several attempts were made to isolate the other marsupial classical class II gene family, namely, DB, resulting in only one DBB pseudogene being found. These findings further support the view that this species has a compromised capacity to respond to pathogen evolution, emerging infectious diseases and environmental changes.     

Landscape genetics of the Tasmanian devil: implications for spread of an infectious cancer

Emerging infectious diseases are increasingly recognized in species’ declines and extinctions. Landscape genetics can be used as a tool to predict disease emergence and spread. The Tasmanian devil is threatened with extinction by a nearly 100% fatal transmissible cancer, which has spread across 95% of the species’ geographic range in 20 years. Here, we present a landscape genetic analysis in the last remaining uninfected parts of the Tasmanian devil’s geographic range to: describe population genetic structure, characterize genetic diversity, and test the influence of landscape variables on Tasmanian devil gene flow to assess the potential for disease spread. In contrast to previous genetic studies on Tasmanian devils showing evidence for two genetic populations island-wide, our genetic based assignment tests and spatial principal components analyses suggest at least two, and possibly three, populations in a study area that is approximately 15% of the size of the overall species’ geographic range. Positive spatial autocorrelation declined at about 40 km, in contrast to 80 km in eastern populations, highlighting the need for range-wide genetic studies. Strong genetic structure was found between devils in the northern part of the study area and those found south of Macquarie Harbor, with weaker structure found between the northeastern and northwestern portion of our study area. Consistent with previous work, we found low overall genetic diversity, likely owing to a combination of founder effects and extreme weather events thousands of years ago that likely caused large-scale population declines. We also found possible signs of recent bottlenecks, perhaps resulting from forest clearing for dairy farming in the central part of the study area. This human disturbance also may have contributed to weak genetic structuring detected between the northeastern and northwestern part of the study area. Individual-based least cost path modeling showed limited influence of landscape variables on gene flow, with weak effects of variation in elevation in the northeast. In the northwest, however, landscape genetic models did not perform better than the null isolation-by-distance model. At the larger spatial scale of the northern part of the study area, elevation and temperatures were negatively correlated with gene flow, consistent with low dispersal suitability of higher elevation habitats that have lower temperatures and dense, wet vegetation. Overall, Tasmanian devils are a highly vagile species for which dispersal and gene flow appear to be influenced little by landscape features, and spread of devil facial tumor disease to the remaining portion of the devil’s geographic range seems imminent. Nonetheless, strong genetic structure found between the northern and southern portions of our study area, combined with low densities and limited possible colonization of DFTD from the east suggest there is some time for implementation of management strategies.     

Temporal partitioning of activity: rising and falling top‐predator abundance triggers community‐wide shifts in diel activity

Top predators cause avoidance behaviours in competitors and prey, which can lead to niche partitioning and facilitate coexistence. We investigate changes in partitioning of the temporal niche in a mammalian community in response to both the rapid decline in abundance of a top predator and its rapid increase, produced by two concurrent natural experiments: 1) the severe decline of the Tasmanian devil due to a transmissible cancer, and 2) the introduction of Tasmanian devils to an island, with subsequent population increase. We focus on devils, two mesopredators and three prey species, allowing us to examine niche partitioning in the context of intra‐ and inter‐specific competition, and predator–prey interactions. The most consistent shift in temporal activity occurred in devils themselves, which were active earlier in the night at high densities, presumably because of heightened intraspecific competition. When devils were rare, their closest competitor, the spotted‐tailed quoll, increased activity in the early part of the night, resulting in increased overlap with the devil's temporal niche and suggesting release from interference competition. The invasive feral cat, another mesopredator, did not shift its temporal activity in response to either decreasing or increasing devil densities. Shifts in temporal activity of the major prey species of devils were stronger in response to rising than to falling devil densities. We infer that the costs associated with not avoiding predators when their density is rising (i.e. death) are higher than the costs of continuing to adopt avoidance behaviours as predator densities fall (i.e. loss of foraging opportunity), so rising predator densities may trigger more rapid shifts. The rapid changes in devil abundance provide a unique framework to test how the non‐lethal effects of top predators affect community‐wide partitioning of temporal niches, revealing that this top predator has an important but varied influence on the diel activity of other species.     

Lack of genetic diversity across diverse immune genes in an endangered mammal,the Tasmanian devil (Sarcophilus harrisii)

The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction due to the spread of devil facial tumour disease. Polymorphisms in immune genes can provide adaptive potential to resist diseases. Previous studies in diversity at immune loci in wild species have almost exclusively focused on genes of the major histocompatibility complex (MHC); however, these genes only account for a fraction of immune gene diversity. Devils lack diversity at functionally important immunity loci, including MHC and Toll‐like receptor genes. Whether there are polymorphisms at devil immune genes outside these two families is unknown. Here, we identify polymorphisms in a wide range of key immune genes, and develop assays to type single nucleotide polymorphisms (SNPs) within a subset of these genes. A total of 167 immune genes were examined, including cytokines, chemokines and natural killer cell receptors. Using genome‐level data from ten devils, SNPs within coding regions, introns and 10 kb flanking genes of interest were identified. We found low polymorphism across 167 immune genes examined bioinformatically using whole‐genome data. From this data, we developed long amplicon assays to target nine genes. These amplicons were sequenced in 29–220 devils and found to contain 78 SNPs, including eight SNPS within exons. Despite the extreme paucity of genetic diversity within these genes, signatures of balancing selection were exhibited by one chemokine gene, suggesting that remaining diversity may hold adaptive potential. The low functional diversity may leave devils highly vulnerable to infectious disease, and therefore, monitoring and preserving remaining diversity will be critical for the long‐term management of this species. Examining genetic variation in diverse immune genes should be a priority for threatened wildlife species. This study can act as a model for broad‐scale immunogenetic diversity analysis in threatened species.     

Space use and temporal partitioning of sympatric Tasmanian devils and spotted‐tailed quolls

Sympatric species can minimise interspecific competition by spatial avoidance or by altering their temporal activity to reduce encounter rates. The Tasmanian devil (Sarcophilus harrisii), the largest carnivorous marsupial, coexists with the smaller spotted‐tailed quoll (Dasyurus maculatus) in Tasmania, Australia. Quolls may be susceptible to interspecific competition from devils, because they utilise similar habitats, consume similar prey species and are displaced by devils at food sources. Such competition might cause quolls to spatially or temporally avoid devils. To investigate whether spatial or temporal avoidance occurred, we deployed GPS collars on sympatric devils and quolls and conducted a camera survey at a site in northwest Tasmania where the devil population was not affected by devil facial tumour disease. GPS tracking coincided with the lactation period when devils and quolls had young in dens and continued until weaning occurred. We found little spatial segregation of home range and core area placement between devils and quolls and among devils. Quolls showed more spatial segregation within the sexes than between them. Devils had larger home ranges than quolls. Male devils had larger home ranges than females, but there was no difference in home range size between the sexes of quolls. Females of both species travelled significantly further per night than did males. There was moderate temporal partitioning between the two species: devil activity peaked after dusk and devils remained active until the early morning, while quoll activity showed distinct peaks around dusk and dawn. In conclusion, quolls did not spatially avoid devils but moderate temporal partitioning occurred. It is plausible that quolls are active at different times of the diel cycle to reduce encountering devils, but further studies are needed to resolve the cause of this temporal partitioning.     

The differentiation state of the Schwann cell progenitor drives phenotypic variation between two contagious cancers

Contagious cancers are a rare pathogenic phenomenon in which cancer cells gain the ability to spread between genetically distinct hosts. Nine examples have been identified across marine bivalves, dogs and Tasmanian devils, but the Tasmanian devil is the only mammalian species known to have given rise to two distinct lineages of contagious cancer, termed Devil Facial Tumour 1 (DFT1) and 2 (DFT2). Remarkably, DFT1 and DFT2 arose independently from the same cell type, a Schwann cell, and while their ultra-structural features are highly similar they exhibit variation in their mutational signatures and infection dynamics. As such, DFT1 and DFT2 provide a unique framework for investigating how a common progenitor cell can give rise to distinct contagious cancers. Using a proteomics approach, we show that DFT1 and DFT2 are derived from Schwann cells in different differentiation states, with DFT2 carrying a molecular signature of a less well differentiated Schwann cell. Under inflammatory signals DFT1 and DFT2 have different gene expression profiles, most notably involving Schwann cell markers of differentiation, reflecting the influence of their distinct origins. Further, DFT2 cells express immune cell markers typically expressed during nerve repair, consistent with an ability to manipulate their extracellular environment, facilitating the cell’s ability to transmit between individuals. The emergence of two contagious cancers in the Tasmanian devil suggests that the inherent plasticity of Schwann cells confers a vulnerability to the formation of contagious cancers.     

Ant-plant symbioses: Stalking the chuyachaqui

According to Quechua-speaking peoples, orchard-like stands ('Supay Chacras') of two Amazonian ant-plant species are cultivated by the devil, or 'Chuyachaqui'. These "devil gardens" offer extreme examples of specializations that have evolved repeatedly in ant-plant associations. Numerous investigations are beginning to disclose the identity of the Chuyachaqui - the forces behind evolutionary specialization in ant-plant symbioses. These developments have important implications for our understanding of modes of coevolution in symbiotic mutualism, remarkable convergent similarities in the form of ant-plant symbioses on different continents, and pronounced intercontinental differences in the diversity and taxonomic composition of associates.     

Trophic rewilding establishes a landscape of fear: Tasmanian devil introduction increases risk‐sensitive foraging in a key prey species

Global declines of large carnivores have reduced the ‘landscape of fear’ that constrains the behaviour of other species. In recent years, active and passive trophic rewilding have potentially begun restoring these lost top–down controls. The Tasmanian devil Sarcophilus harrisii has declined severely due to a novel transmissible cancer. In response to extinction fears, devils were introduced to the devil‐free Maria Island, where their abundance rapidly increased. We tested how this introduction influenced risk‐sensitive foraging in the common brushtail possum Trichosurus vulpecula, a major prey species for devils, using giving‐up densities (GUDs). Before the introduction of devils, possum GUDs on Maria Island were indistinguishable from the long‐diseased region of Tasmania, where devils have been rare since ~2000. Three years after devil introduction, GUDs were 64% higher on Maria Island than the control region, demonstrating that after an initial period of high mortality, possums quickly adopted risk‐sensitive foraging behaviours. Devil activity across Maria Island was variable, leading to a heterogeneous landscape of fear and highlighting that top predators must be at functional densities to elicit behavioural responses from prey. Our study provides strong evidence that top predators modify the behaviour of prey by instilling fear, causing rapid ecological change following recoveries.     

Extreme Telomere Length Dimorphism in the Tasmanian Devil and Related Marsupials Suggests Parental Control of Telomere Length

Telomeres, specialised structures that protect chromosome ends, play a critical role in preserving chromosome integrity. Telomere dynamics in the Tasmanian devil (Sarcophilus harrisii) are of particular interest in light of the emergence of devil facial tumour disease (DFTD), a transmissible malignancy that causes rapid mortality and threatens the species with extinction. We used fluorescent in situ hybridisation to investigate telomere length in DFTD cells, in healthy Tasmanian devils and in four closely related marsupial species. Here we report that animals in the Order Dasyuromorphia have chromosomes characterised by striking telomere length dimorphism between homologues. Findings in sex chromosomes suggest that telomere length dimorphism may be regulated by events in the parental germlines. Long telomeres on the Y chromosome imply that telomere lengthening occurs during spermatogenesis, whereas telomere diminution occurs during oogenesis. Although found in several somatic cell tissue types, telomere length dimorphism was not found in DFTD cancer cells, which are characterised by uniformly short telomeres. This is, to our knowledge, the first report of naturally occurring telomere length dimorphism in any species and suggests a novel strategy of telomere length control. Comparative studies in five distantly related marsupials and a monotreme indicate that telomere dimorphism evolved at least 50 million years ago.     

Harpagoside: from Kalahari Desert to pharmacy shelf

Harpagoside is an iridoid glycoside that was first isolated from Harpagophytum procumbens (devil’s claw, Pedaliaceae), a medicinal plant in which it is the major constituent of the iridoid pool. Both the pure compound and devil’s claw extracts have potent anti-rheumatic, anti-inflammatory and analgesic effects. According to the European Pharmacopoeia commercial devil’s claw products should contain at least 1.2% harpagoside. However, the compound has also been isolated from several other plant species and in vitro plant culture systems. Recent advances in knowledge of harpagoside distribution, biosynthesis/accumulation and pharmacology are summarized in this review. We also discuss the possible synergism and/or antagonism between major constituents in harpagoside-containing phytopharmaceutical products. Finally, future perspectives for its potential application are highlighted.