Pan genome of the phytoplankton Emiliania underpins its global distribution

Coccolithophores have influenced the global climate for over 200 million years1. These marine phytoplankton can account for 20 per cent of total carbon fixation in some systems2. They form blooms that can occupy hundreds of thousands of square kilometres and are distinguished by their elegantly sculpted calcium carbonate exoskeletons (coccoliths), rendering themvisible fromspace3.Although coccolithophores export carbon in the form of organic matter and calcite to the sea floor, they also release CO2 in the calcification process. Hence, they have a complex influence on the carbon cycle, driving either CO2 production or uptake, sequestration and export to the deep ocean4. Here we report the first haptophyte reference genome, from the coccolithophore Emiliania huxleyi strain CCMP1516, and sequences from 13 additional isolates. Our analyses reveal a pan genome (core genes plus genes distributed variably between strains) probably supported by an atypical complement of repetitive sequence in the genome. Comparisons across strains demonstrate thatE. huxleyi, which has long been considered a single species, harbours extensive genome variability reflected in different metabolic repertoires. Genome variability within this species complex seems to underpin its capacity both to thrive in habitats ranging from the equator to the subarctic and to form large-scale episodic blooms under a wide variety of environmental conditions

Evaluating the provision of Further Enabling Care at Home (FECH+) for informal caregivers of older adults discharged home from hospital: Protocol for a multicentre randomised controlled trial

Introduction: There are personal and societal benefits from caregiving; however, caregiving can jeopardise caregivers’ health. The Further Enabling Care at Home (FECH+) programme provides structured nurse support, through telephone outreach, to informal caregivers of older adults following discharge from acute hospital care to home. The trial aims to evaluate the efficacy of the FECH+ programme on caregivers’ health-related quality of life (HRQOL) after care recipients’ hospital discharge. Methods and analysis: A multisite, parallel-group, randomised controlled trial with blinded baseline and outcome assessment and intention-to-treat analysis, adhering to Consolidated Standards of Reporting Trials guidelines will be conducted. Participants (N=925 dyads) comprising informal home caregiver (18 years or older) and care recipient (70 years or older) will be recruited when the care recipient is discharged from hospital. Caregivers of patients discharged from wards in three hospitals in Australia (one in Western Australia and two in Queensland) are eligible for inclusion. Participants will be randomly assigned to one of the two groups. The intervention group receive the FECH+ programme, which provides structured support and problem-solving for the caregiver after the care recipient’s discharge, in addition to usual care. The control group receives usual care. The programme is delivered by a registered nurse and comprises six 30–45min telephone support sessions over 6months. The primary outcome is caregivers’ HRQOL measured using the Assessment of Quality of Life—eight dimensions. Secondary outcomes include caregiver preparedness, strain and distress and use of healthcare services. Changes in HRQOL between groups will be compared using a mixed regression model that accounts for the correlation between repeated measurements. Ethics and dissemination: Participants will provide written informed consent. Ethics approvals have been obtained from Sir Charles Gairdner and Osborne Park Health Care Group, Curtin University, Griffith University, Gold Coast Health Service and government health data linkage services. Findings will be disseminated through presentations, peer-reviewed journals and conferences. Trial registration number: ACTRN12620000060943

A morphometric dive into fish diversity

International audienceTrait-based approaches are increasingly popular in ecology to describe communities and their responses to natural or anthropogenic changes. Morphology is an integrative trait that combines functional and evolutionary information. However, the objective and quantitative description of the morphological diversity is quite challenging. Modern morphometrics encompass an array of mathematical approaches that turn shapes into quantitative variables. For models with no or only a few homologous points, outline analysis (e.g., elliptical Fourier transform) converts the outline geometry into quantitative variables, which can be used in the multivariate framework. The elliptical Fourier transform here describes the shape of 85 fish species found in the North Sea. This study shows that the main component of morphological diversity in the North sea is the elongation and development of dorsal, pelvic, and caudal fins. The spatial distribution of morphological diversity decreases along a latitudinal gradient, with higher diversity in the southern part of the study area. Compared to species diversity, our results indicate that environmental conditions filter morphological traits in the northern North Sea. Outline analysis is a powerful approach to provide an objective description of fish morphology and to improve our understanding of the diversity of large marine ecosystems

Comparative genomic analysis of three Leishmania species that cause diverse human disease

Leishmania parasites cause a broad spectrum of clinical disease. Here we report the sequencing of the genomes of two species of Leishmania: Leishmania infantum and Leishmania braziliensis. The comparison of these sequences with the published genome of Leishmania major reveals marked conservation of synteny and identifies only 200 genes with a differential distribution between the three species. L. braziliensis, contrary to Leishmania species examined so far, possesses components of a putative RNA-mediated interference pathway, telomere-associated transposable elements and spliced leader–associated SLACS retrotransposons. We show that pseudogene formation and gene loss are the principal forces shaping the different genomes. Genes that are differentially distributed between the species encode proteins implicated in host-pathogen interactions and parasite survival in the macrophage