Ancient drainages divide cryptic species in Australia's arid zone: morphological and multi-gene evidence for four new species of Beaked Geckos (Rhynchoedura)

Deserts and other arid zones remain among the least studied biomes on Earth. Emerging genetic patterns of arid-distributed biota suggest a strong link between diversification history and both the onset of aridification and more recent cycles of severe aridification. A previous study based on 1 kb of mtDNA of the monotypic gecko genus Rhynchoedura identified five allopatric clades across the vast Australian arid zone. We supplemented this data with 2.2kb from three nuclear loci and additional mtDNA sequences. Phylogenetic relationships estimated from the mtDNA data with ML and Bayesian methods were largely concordant with relationships estimated with the nDNA data only, and mtDNA and nDNA data combined. These analyses, and coalescent-based species-tree inference methods implemented with (?)BEAST, largely resolve the relationships among them. We also carried out an examination of 19 morphological characters for 268 museum specimens from across Australia, including all 197 animals for which we sequenced mtDNA. The mtDNA clades differ subtly in a number of morphological features, and we describe three of them as new species, raise a fourth from synonymy, and redescribe it and the type species, Rhynchoedura ornata. We also describe a morphologically distinctive new species from Queensland based on very few specimens. The distribution of arid zone clades across what is now relatively homogeneous sand deserts seems to be related to a topographic divide between the western uplands and eastern lowlands, with species' distributions correlated with dryland rivers and major drainage divides. The existence of five cryptic species within the formerly monotypic Rhynchoedura points to ancient divergences within the arid zone that likely were driven by wet phases as well as dry ones.     

Cost-effectiveness of HIV screening in STD clinics, emergency departments, and inpatient units: a model-based analysis

Background

Identifying and treating persons with human immunodeficiency virus (HIV) infection early in their disease stage is considered an effective means of reducing the impact of the disease. We compared the cost-effectiveness of HIV screening in three settings, sexually transmitted disease (STD) clinics serving men who have sex with men, hospital emergency departments (EDs), settings where patients are likely to be diagnosed early, and inpatient diagnosis based on clinical manifestations.

Methods and Findings

We developed the Progression and Transmission of HIV/AIDS model, a health state transition model that tracks index patients and their infected partners from HIV infection to death. We used program characteristics for each setting to compare the incremental cost per quality-adjusted life year gained from early versus late diagnosis and treatment. We ran the model for 10,000 index patients for each setting, examining alternative scenarios, excluding and including transmission to partners, and assuming HAART was initiated at a CD4 count of either 350 or 500 cells/µL. Screening in STD clinics and EDs was cost-effective compared with diagnosing inpatients, even when including only the benefits to the index patients. Screening patients in STD clinics, who have less-advanced disease, was cost-effective compared with ED screening when treatment with HAART was initiated at a CD4 count of 500 cells/µL. When the benefits of reduced transmission to partners from early diagnosis were included, screening in settings with less-advanced disease stages was cost-saving compared with screening later in the course of infection. The study was limited by a small number of observations on CD4 count at diagnosis and by including transmission only to first generation partners of the index patients.

Conclusions

HIV prevention efforts can be advanced by screening in settings where patients present with less-advanced stages of HIV infection and by initiating treatment with HAART earlier in the course of infection.     

Systemic maternal inflammation and neonatal hyperoxia induces remodeling and left ventricular dysfunction in mice

Aims

The impact of the neonatal environment on the development of adult cardiovascular disease is poorly understood. Systemic maternal inflammation is linked to growth retardation, preterm birth, and maturation deficits in the developing fetus. Often preterm or small-for-gestational age infants require medical interventions such as oxygen therapy. The long-term pathological consequences of medical interventions on an immature physiology remain unknown. In the present study, we hypothesized that systemic maternal inflammation and neonatal hyperoxia exposure compromise cardiac structure, resulting in LV dysfunction during adulthood.

Methods and Results

Pregnant C3H/HeN mice were injected on embryonic day 16 (E16) with LPS (80 µg/kg; i.p.) or saline. Offspring were placed in room air (RA) or 85% O₂ for 14 days and subsequently maintained in RA. Cardiac echocardiography, cardiomyocyte contractility, and molecular analyses were performed. Echocardiography revealed persistent lower left ventricular fractional shortening with greater left ventricular end systolic diameter at 8 weeks in LPS/O₂ than in saline/RA mice. Isolated cardiomyocytes from LPS/O₂ mice had slower rates of contraction and relaxation, and a slower return to baseline length than cardiomyocytes isolated from saline/RA controls. α-/β-MHC ratio was increased and Connexin-43 levels decreased in LPS/O₂ mice at 8 weeks. Nox4 was reduced between day 3 and 14 and capillary density was lower at 8 weeks of life in LPS/O₂ mice.

Conclusion

These results demonstrate that systemic maternal inflammation combined with neonatal hyperoxia exposure induces alterations in cardiac structure and function leading to cardiac failure in adulthood and supports the importance of the intrauterine and neonatal milieu on adult health.     

Global conservation priorities for marine turtles

Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a “conservation priorities portfolio” system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world''s 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa.