Viral ecogenomics across the Porifera

BackgroundViruses directly affect the most important biological processes in the ocean via their regulation of prokaryotic and eukaryotic populations. Marine sponges form stable symbiotic partnerships with a wide diversity of microorganisms and this high symbiont complexity makes them an ideal model for studying viral ecology. Here, we used morphological and molecular approaches to illuminate the diversity and function of viruses inhabiting nine sponge species from the Great Barrier Reef and seven from the Red Sea.ResultsViromic sequencing revealed host-specific and site-specific patterns in the viral assemblages, with all sponge species dominated by the bacteriophage order Caudovirales but also containing variable representation from the nucleocytoplasmic large DNA virus families Mimiviridae, Marseilleviridae, Phycodnaviridae, Ascoviridae, Iridoviridae, Asfarviridae and Poxviridae. Whilst core viral functions related to replication, infection and structure were largely consistent across the sponge viromes, functional profiles varied significantly between species and sites largely due to differential representation of putative auxiliary metabolic genes (AMGs) and accessory genes, including those associated with herbicide resistance, heavy metal resistance and nylon degradation. Furthermore, putative AMGs varied with the composition and abundance of the sponge-associated microbiome. For instance, genes associated with antimicrobial activity were enriched in low microbial abundance sponges, genes associated with nitrogen metabolism were enriched in high microbial abundance sponges and genes related to cellulose biosynthesis were enriched in species that host photosynthetic symbionts.ConclusionsOur results highlight the diverse functional roles that viruses can play in marine sponges and are consistent with our current understanding of sponge ecology. Differential representation of putative viral AMGs and accessory genes across sponge species illustrate the diverse suite of beneficial roles viruses can play in the functional ecology of these complex reef holobionts

Prevalent and persistent viral infection in cultures of the coral algal endosymbiont Symbiodinium

© 2017, Springer-Verlag Berlin Heidelberg. Reef corals are under threat from bleaching and disease outbreaks that target both the host animal and the algal symbionts within the coral holobiont. A viral origin for coral bleaching has been hypothesized, but direct evidence has remained elusive. Using a multifaceted approach incorporating flow cytometry, transmission electron microscopy, DNA and RNA virome sequencing, we show that type C1 Symbiodinium cultures host a nucleocytoplasmic large double-stranded DNA virus (NCLDV) related to Phycodnaviridae and Mimiviridae, a novel filamentous virus of unknown phylogenetic affiliation, and a single-stranded RNA virus related to retroviruses. We discuss implications of these findings for laboratory-based experiments using Symbiodinium cultures

A genomic view of the microbiome of coral reef demosponges

Sponges underpin the productivity of coral reefs, yet few of their microbial symbionts have been functionally characterised. Here we present an analysis of ~1200 metagenome-assembled genomes (MAGs) spanning seven sponge species and 25 microbial phyla. Compared to MAGs derived from reef seawater, sponge-associated MAGs were enriched in glycosyl hydrolases targeting components of sponge tissue, coral mucus and macroalgae, revealing a critical role for sponge symbionts in cycling reef organic matter. Further, visualisation of the distribution of these genes amongst symbiont taxa uncovered functional guilds for reef organic matter degradation. Genes for the utilisation of sialic acids and glycosaminoglycans present in sponge tissue were found in specific microbial lineages that also encoded genes for attachment to sponge-derived fibronectins and cadherins, suggesting these lineages can utilise specific structural elements of sponge tissue. Further, genes encoding CRISPR and restriction-modification systems used in defence against mobile genetic elements were enriched in sponge symbionts, along with eukaryote-like gene motifs thought to be involved in maintaining host association. Finally, we provide evidence that many of these sponge-enriched genes are laterally transferred between microbial taxa, suggesting they confer a selective advantage within the sponge niche and therefore play a critical role in host ecology and evolution

[PP. 27.24] DIAGNOSTIC ACCURACY AND DIAGNOSTIC GAIN OF CRITERIA TO INTERPRET UNILATERALLY SELECTIVE ADRENAL VEIN SAMPLING (AVS) RESULTS

Objective: 10–20% of AVS performed in Excellence centers for primary aldosteronism (PA) are not bilaterally selective. The ratio of cortisol-corrected aldosterone concentration between adrenal vein and inferior vena cava (unilateral ratio, UR) has been proposed to interpret unilaterally selective AVS [1]:UR<0.5could suggest unilateral PA on the opposite side; UR >5.5 could suggest unilateral PA on the same side, and UR 0.5–5.5 would be inconclusive. Design and method: This retrospective study evaluates the diagnostic value of the UR on AVS data collected over10 years in a referral centre. French AVS-consensus criteria (selectivity index >2, lateralisation ratio >4) were used for AVS interpretation. We first assessed the numbers of cases with left and right UR both <0.5 or both >5.5, because in these cases the interpretation of unilaterally selective AVS will depend only on the side of successful adrenal vein cannulation, not on the side of the disease. We then assessed the sensitivity, specificity and PPV of these criteria for the diagnosis of unilateral PA. Cases with left and right UR both <0.5 or both >5.5 were counted as false positives for these calculations. We finally assessed the diagnostic impact of using the unilateral criteria in case of unilaterally selective AVS. Results: -537AVS were performed from 2001–2010, 64(12%) were not bilaterally selective using the reference criteria (28unilaterally selective and 36 bilaterally non-selective), 287 (53%) were diagnostic of bilateral PA, 99 (18%) of left PA and 87 (16%) of right PA [Table 1]. -Among 473 bilaterally selective AVS, 7 (1.5%) had left and right UR both <0.5 and 32 (7%) had left and right UR both >5.5 [Table 2]. -Sensitivity of UR <0.5 to detect unilateral PA was 55%, specificity 91%, PPV79%. -Sensitivity of UR >5.5 was 51%, specificity71%, PPV53% [Table3]. -Using these criteria to interpret 28 unilaterally selective AVS led to diagnose 2right PA but 0left PA with a contralateral UR <0.5, 10 right PA and 6left PA with an ipsilateral UR >5.5, the remaining 10 cases staying inconclusive. However, among the 16 unilateral PA diagnosed with an ipsilateral UR >5.5, we must expect 8 false positives

Visual tools for developing student capacity for cross-disciplinary collaboration, innovation and entrepreneurship

This volume identifies and documents pedagogical and practice-based visual approaches to scaffolding and developing capacity for cross-disciplinary collaboration, innovation and entrepreneurship