Unravelling the mystery of endemic versus translocated populations of the endangered Australian lungfish (Neoceratodus forsteri)

The Australian lungfish is a primitive and endangered representative of the subclass Dipnoi. The distribution of this species is limited to south-east Queensland, with some populations considered endemic and others possibly descending from translocations in the late nineteenth century shortly after European discovery. Attempts to resolve the historical distribution of this species have met with conflicting results based on descriptive genetic studies. Understanding if all populations are endemic or some are the result of, or influenced by, translocation events, has implications for conservation management. In this work, we analysed the genetic variation at three types of markers (mtDNA genomes, 11 STRs and 5196 nuclear SNPs) using the approximate Bayesian computation (ABC) algorithm to compare several demographic models. We postulated different contributions of Mary River and Burnett River gene pools into the Brisbane River and North Pine River populations, related to documented translocation events. We ran the analysis for each marker type separately, and we also estimated the posterior probabilities of the models combining the markers. Nuclear SNPs have the highest power to correctly identify the true model among the simulated datasets (where the model was known), but different marker types typically provided similar answers. The most supported demographic model able to explain the real dataset implies that an endemic gene pool is still present in the Brisbane and North Pine Rivers and coexists with the gene pools derived from past documented translocation events. These results support the view that ABC modelling can be useful to reconstruct complex historical translocation events with contemporary implications, and will inform ongoing conservation efforts for the endangered and iconic Australian lungfish.

Relaxation of Natural Selection in the Evolution of the Giant Lungfish Genomes

Nonadaptive hypotheses on the evolution of eukaryotic genome size predict an expansion when the process of purifying selection becomes weak. Accordingly, species with huge genomes, such as lungfish, are expected to show a genome-wide relaxation signature of selection compared with other organisms. However, few studies have empirically tested this prediction using genomic data in a comparative framework. Here, we show that 1) the newly assembled transcriptome of the Australian lungfish, Neoceratodus forsteri, is characterized by an excess of pervasive transcription, or transcriptional leakage, possibly due to suboptimal transcriptional control, and 2) a significant relaxation signature in coding genes in lungfish species compared with other vertebrates. Based on these observations, we propose that the largest known animal genomes evolved in a nearly neutral scenario where genome expansion is less efficiently constrained.

Quantifying movement of multiple threatened species to inform adaptive management of environmental flows

There is a growing need for water managers to refine and optimise environmental flow strategies (e-flows) to balance water requirements for humans and nature. With increasing demands for freshwater and consequent declines in biodiversity, managers are faced with the problem of how to adaptively manage e-flows for multiple stakeholders and species whose flow requirements may overlap or vary. This study assessed the effectiveness of a regulated e-flow release strategy from a dam, aimed at providing movement opportunities and facilitating reproductive processes for multiple threatened species. Movements of 24 Mary River cod (Maccullochella mariensis), 20 Australian lungfish (Neoceratodus forsteri) and 13 Mary River turtle (Elusor macrurus) were quantified using acoustic telemetry over a three-year period. The influence of regulated e-flow releases, season, river depth, water temperature and rainfall on animal movements was assessed using Generalised linear mixed models (GLMMs). Models showed that hydraulic connectivity provided by both natural flows and regulated e-flow releases facilitated movement of all three species between pool habitats, throughout the year. Mary River turtles made extensive use of regulated e-flow releases when moving between habitats, whereas Mary River cod and Australian lungfish required additional natural rises in river height above the regulated e-flows to trigger movements. Significant movement activity was also recorded for cod and turtles during the dry season (winter and spring), broadly coinciding with breeding periods for these species. The effectiveness of, and potential improvements to, current e-flow strategies to sustain key life-history requirements of these species is discussed. Findings suggest a revised e-flow strategy with relatively minor increases in the magnitude of e-flow releases throughout winter and spring, would be effective in providing movement opportunities and supporting reproductive success for all three species. This study demonstrates that by quantifying movement behaviour in an e-flow context, ecological risk assessment frameworks can then be used to assess and provide for critical life-history requirements of multiple species within the context of a highly regulated system under increasing water use demands.

Age structure of the Australian lungfish (Neoceratodus forsteri)

The Australian lungfish has been studied for more than a century without any knowledge of the longevity of the species. Traditional methods for ageing fish, such as analysis of otolith (ear stone) rings is complicated in that lungfish otoliths differ from teleost fish in composition. As otolith sampling is also lethal, this is not appropriate for a protected species listed under Australian legislation. Lungfish scales were removed from 500 fish from the Brisbane, Burnett and Mary rivers. A sub–sample of scales (85) were aged using bomb radiocarbon techniques and validated using scales marked previously with oxytetracycline. Lungfish ages ranged from 2.5–77 years of age. Estimated population age structures derived using an Age Length Key revealed different recruitment patterns between river systems. There were statistically significant von Bertalanffy growth model parameters estimated for each of the three rivers based on limited sample sizes. In addition, length frequency distributions between river systems were also significantly different. Further studies will be conducted to review drivers that may explain these inter-river differences.

Monitoring age-related trends in genomic diversity of Australian lungfish

An important challenge for conservation science is to detect declines in intraspecific diversity so that management action can be guided towards populations or species at risk. The lifespan of Australian lungfish (Neoceratodus forsteri) exceeds 80 years, and human impacts on breeding habitat over the last half century may have impeded recruitment, leaving populations dominated by old postreproductive individuals, potentially resulting in a small and declining breeding population. Here, we conduct a "single-sample" evaluation of genetic erosion within contemporary populations of the Australian lungfish. Genetic erosion is a temporal decline in intraspecific diversity due to factors such as reduced population size and inbreeding. We examined whether young individuals showed signs of reduced genetic diversity and/or inbreeding using a novel bomb radiocarbon dating method to age lungfish nonlethally, based on 14 C ratios of scales. A total of 15,201 single nucleotide polymorphic (SNP) loci were genotyped in 92 individuals ranging in age from 2 to 77 years old. Standardized individual heterozygosity and individual inbreeding coefficients varied widely within and between riverine populations, but neither was associated with age, so perceived problems with recruitment have not translated into genetic erosion that could be considered a proximate threat to lungfish populations. Conservation concern has surrounded Australian lungfish for over a century. However, our results suggest that long-lived threatened species can maintain stable levels of intraspecific variability when sufficient reproductive opportunities exist over the course of a long lifespan.

DNA barcoding of freshwater fishes and the development of a quantitative qPCR assay for the species-specific detection and quantification of fish larvae from plankton samples

The barcoding of mitochondrial cytochrome c oxidase subunit 1 (coI) gene was amplified and sequenced from 16 species of freshwater fishes found in Lake Wivenhoe (south-eastern Queensland, Australia) to support monitoring of reservoir fish populations, ecosystem function and water health. In this study, 630-650 bp sequences of the coI barcoding gene from 100 specimens representing 15 genera, 13 families and two subclasses of fishes allowed 14 of the 16 species to be identified and differentiated. The mean ± s.e. Kimura 2 parameter divergence within and between species was 0.52 ± 0.10 and 23.8 ± 2.20% respectively, indicating that barcodes can be used to discriminate most of the fish species accurately. The two terapontids, Amniataba percoides and Leiopotherapon unicolor, however, shared coI DNA sequences and could not be differentiated using this gene. A barcoding database was established and a qPCR assay was developed using coI sequences to identify and quantify proportional abundances of fish species in ichthyoplankton samples from Lake Wivenhoe. These methods provide a viable alternative to the time-consuming process of manually enumerating and identifying ichthyoplankton samples.

Spawning activity of the Australian lungfish Neoceratodus forsteri in an impoundment

This study assessed the spawning activity of the threatened Australian lungfish Neoceratodus forsteri by measuring egg densities within the artificial habitat of a large impoundment (Lake Wivenhoe, Australia). Eggs were sampled (August to November 2009) from multiple locations across the impoundment, but occurred at highest densities in water shallower than 40 cm along shorelines with a dense cover of submerged terrestrial vegetation. The numbers of eggs declined over the study period and all samples were dominated by early developmental stages and high proportions of unviable eggs. The quality of the littoral spawning habitats declined over the study as flooded terrestrial grasses decomposed and filamentous algae coverage increased. Water temperatures at the spawning site exhibited extreme variations, ranging over 20·4° C in water shallower than 5 cm. Dissolved oxygen concentrations regularly declined to <1 mg l⁻¹ at 40 and 80 cm water depth. Spawning habitats utilised by N. forsteri within impoundments expose embryos to increased risk of desiccation or excessive submergence through water-level variations, and extremes in temperature and dissolved oxygen concentration that present numerous challenges for successful spawning and recruitment of N. forsteri in large impoundment environments.

A new coccidian (Apicomplexa: Eimeriidae) from Galápagos tortoise, Chelonoidis sp. (Testudines: Testudinidae), from the Dallas Zoo

During January 1994, feces from a captive juvenile Galápagos tortoise, Chelonoidis sp., from the Dallas Zoo, Dallas County, Texas was examined for coccidia. The tortoise was found to harbor an eimerian which is described as new. Sporulated oocysts of Eimeria iversoni n. sp. were ovoidal with a smooth, single-layered wall (∼ 0.5-0.8) that measured (L × W) 13.5 × 10.3 μm, with a length/width (L/W) ratio of 1.3; micropyle, oocyst residuum, and polar granule(s) were all absent; 2 conical projections were present on 1 end of oocyst and measured 1.0-1.5. Sporocysts were elongate-ellipsoidal and measured 8.3 × 4.5 μm, with L/W of 1.8; a Stieda body (∼ 0.5 high) was present, but substieda and parastieda bodies were absent; a sporocyst residuum was composed of 2-5 granules in a compact mass between sporozoites; sporozoites were banana-shaped and measured 9.5 × 2.5 in situ, with an ellipsoidal posterior refractile body and a spheroidal anterior refractile body. This is only the second time an eimerian has been reported from Galápagos tortoises.

Predicting the vulnerability of reservoirs to poor water quality and cyanobacterial blooms

Cyanobacterial blooms in drinking water reservoirs present a major ecosystem functioning and human health issue. The ability to predict reservoir vulnerability to these blooms would provide information critical for decision making, hazard prevention and management. We developed a new, comparative index of vulnerability based on simple measures of reservoir and catchment characteristics, rather than water quality data, which were instead used to test the index's effectiveness. Testing was based on water quality data collected over a number of seasons and years from 15 drinking water reservoirs in subtropical, southeast Queensland. The index correlated significantly and strongly with algal cell densities, including potentially toxic cyanobacteria, as well as with the proportions of cyanobacteria in summer months. The index also performed better than each of the measures of reservoir and catchment characteristics alone, and as such, was able to encapsulate the physical characteristics of subtropical reservoirs, and their catchments, into an effective indicator of the vulnerability to summer blooms. This was further demonstrated by calculating the index for a new reservoir to be built within the study region. Under planned dimensions and land use, a comparatively high level of vulnerability was reached within a few years. However, the index score and the number of years taken to reach a similar level of vulnerability could be reduced simply by decreasing the percentage of grazing land cover via revegetation within the catchment. With climate change, continued river impoundment and the growing demand for potable water, our index has potential decision making benefits when planning future reservoirs to reduce their vulnerability to cyanobacterial blooms.

Guidelines for treatment of onychomycosis

These guidelines for management of onychomycosis have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation.

Onychomycosis: current treatment and future challenges

Onychomycosis is a fungal infection of the nails, more often of the toenails. It is a common condition, with an estimated overall prevalence of 3-10% in European populations. Dermatophytes, especially Trichophyton rubrum and Trichophyton mentagrophytes, are the usual pathogens. Some 50% of infected patients fail to seek medical advice. Medically confirmed onychomycosis should be treated. This recommendation is based on several disease-specific considerations: cosmetic and functional disability, lack of spontaneous remission, impairment of health and wellbeing in elderly patients and the need to reduce contamination in communal bathing places. Current treatments for onychomycosis include oral antifungal agents such as terbinafine (Lamisil) and itraconazole (Sporanox). They offer significantly improved rates of cure, shorter treatment regimens and a lower level of adverse events than was previously the case. Comparative studies have shown that terbinafine is more effective than griseofulvin, fluconazole or itraconazole in the treatment of this condition, providing a cure rate of 70-80% and an excellent tolerability profile. Terbinafine is also the most cost-effective agent. However, several problems remain that will provide future challenges in the treatment of onychomycosis, not least the consistent treatment failure rate of 20%. In many of these cases, surgery may need to precede drug therapy in order to maximise the prospects of clinical and mycological cure. In addition, duration of treatment also needs to be more closely adjusted to the individual case by prior identification of severity and extent of toenail infection, and combined oral and topical therapy also requires further investigation.

Oral terbinafine (Lamisil) in the treatment of fungal infections of the skin and nails

The efficacy and safety of antifungal drugs depend upon their mode of action, the minimal inhibitory concentration (MIC) and its relationship to the minimal fungicidal concentration (MFC), the spectrum of activity and drug kinetics at the involved site. Terbinafine acts at the fungal cell wall. Its MIC against dermatophytes is the lowest of all currently available systemic antifungal agents. It is the only one with an MIC:MFC ratio of 1:1 so that terbinafine should be effective over very short treatment durations in dermatophyte infections of the scalp, palms and soles, and nail, providing that drug penetration is adequate, as it appears to be. Therapeutic levels persist for a considerable period after the cessation of treatment, also favouring short-duration therapy. Terbinafine is effective against all varieties of dermatophyte. Terbinafine given over 4 weeks or less is effective against Trichophyton of the scalp in children and adults. Its efficacy in zoophilic ectrothrix infection is anecdotal, but it is likely on theoretical grounds. Terbinafine is also effective against pityriasis versicolor and vaginal candidosis, but only topically. As of March 1996, around 3,000,000 patients have been treated worldwide with terbinafine, mostly for 12 weeks for toe-nail onychomycosis. Gastro-intestinal disturbance and minor skin rashes are seen in 5 and 2% of patients, respectively.

Comparison of fluticasone propionate ointment, 0.005%, and betamethasone-17,21-dipropionate ointment, 0.05%, in the treatment of psoriasis

The efficacy, safety, and tolerability of the mid-potency corticosteroid, fluticasone propionate ointment, 0.005%, were compared with those of a high-potency corticosteroid, betamethasone-17,21-dipropionate ointment, 0.05%, in a twelve-week randomized, double-blind, parallel-group, multicenter study of seventy-four patients with moderate-to-severe psoriasis. Efficacy was evaluated for four weeks; safety was evaluated over a twelve-week period. Fluticasone ointment, 0.005%, was not significantly different from betamethasone ointment, 0.05%, at day 15 (P = 0.147), at the end of treatment analysis (P = 0.245), or at day 29 (P = 0.154). Neither medication resulted in any abnormal laboratory values over the twelve-week study period, including plasma cortisol levels. Both medications were well tolerated.

Oral therapeutic agents in fungal nail disease

Oral griseofulvin has been the first-line drug in the therapy of dermatophyte onychomycosis for many years. Even when used long-term, it is effective in only about 30% of patients. Ketoconazole is not much more effective than griseofulvin in toenail infections, and there are significant problems with hepatotoxicity. Recently the triazoles, itraconazole and fluconazole, and the allylamine, terbinafine, were introduced and are believed to be potentially suitable for the oral treatment of fungal nail infection. Terbinafine is particularly effective in the treatment of dermatophyte onychomycosis, with a much shorter treatment period than griseofulvin. Cure rates of well over 80% have been noted in fingernail and toenail infection during treatment periods of 6 and 12 weeks, respectively. Itraconazole, 200 mg/day, has been noted in some studies to be similarly effective in the same treatment period. Few studies of fluconazole in nail infection have been carried out. These new agents appear to be safe, and results thus far suggest that they will soon overtake griseofulvin as the drug of choice in the oral therapy of nail infection.

Prevalence of dermatophyte onychomycosis in the United Kingdom: results of an omnibus survey

A computer omnibus survey to determine the prevalence of onychomycosis in the United Kingdom was carried out in the early part of 1990. A total population of 9332 adults, aged 16 years and over, was interviewed face-to-face, and a questionnaire completed, which consisted of questions and photographs of various nail dystrophies, including onychomycosis. The results in the population surveyed revealed a prevalence of dermatophyte nail infection of 2.8% in men and 2.6% in women. In the group aged 16-34 years, the prevalence rate was 1.3%; this increased to 2.4% in the group aged 35-50 years, and to 4.7% in those aged 55 years or over. Of those found to have onychomycosis, 27% had sought advice from a chiropodist and less than 12% had consulted a specialist. These results suggest that nearly 1.2 million people in the UK have a fungal nail infection and the majority had not sought medical advice, although over 80% stated that they would do so if they were aware that their nail disorder was of fungal origin. A similar proportion would wish to be treated if an effective treatment was available.

Comparison of ketoconazole and griseofulvin in the treatment of tinea pedis

Twenty-nine patients with mycologically proven tinea pedis were randomly allocated to oral treatment with either ketoconazole 200 mg daily or griseofulvin 1 g daily for a period of up to 8 weeks. Mycological cure rate at 4 weeks was 33% for ketoconazole and 29% for griseofulvin, and at 8 weeks was 53% and 57% respectively. The efficacy of both drugs in the treatment of interdigital tinea pedis is similar, and is considerably lower than that found with topical imidazole preparations where cure rates of over 70% are generally expected.

Hereditary coproporphyria presenting with photosensitivity induced by the contraceptive pill

A 26-year-old woman developed photosensitivity and jaundice after starting on an oral contraceptive agent. She was found to have hereditary coproporphyria. Histological examination of two liver biopsies taken during and after the acute attack did not reveal any changes thought to be due to hereditary coproporphyria. Screening of the patient's family revealed a further six latent cases.

Efficacy of miconazole in the topical treatment of tinea pedis in sportsmen

A double-blind trial of 2% miconazole in a cream and in a powder base and of the respective vehicles was done in a group of forty-five young sportsmen regularly training and using the showers in a gymnasium. After 4 weeks treatment, the mycological cure rate using the active preparation was 60% compared to 24% for the placebo (P less than 0-05).