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It is difficult to disentangle the many variables (e.g. internal or external cues and random events) that shape the microbiota in the gastrointestinal tract of any living species. Ecological assembly processes applied to microbial communities can elucidate these drivers. In our study, farmed Atlantic cod (Gadus morhua) were fed a diet of 10% macroalgae supplement (Ulva rigida [ULVA] or Ascophyllum nodosum [ASCO] or a non-supplemented control diet [CTRL]) over 12 weeks. We determined the influence of ecological assembly processes using a suite of null-modelling tools. We observed dissimilarity in the abundance of common OTUs over time, which was driven by deterministic assembly. The CTRL samples showed selection as a critical assembly process. While dispersal limitation was a driver of the gut microbiome for fish fed the macroalgae supplemented diet at Week 12 (i.e., ASCO and ULVA). Fish from the ASCO grouping diverged into ASCO_N (normal) and ASCO_LG (lower growth), where ASCO_LG individuals found the diet unpalatable. The recruitment of new taxa overtime was altered in the ASCO_LG fish, with the gut microbiome showing phylogenetic underdispersion (nepotistic species recruitment). Finally, the gut microbiome (CTRL and ULVA) showed increasing robustness to taxonomic disturbance over time and lower functional redundancy. This study advances our understanding of the ecological assembly and succession in the hindgut of juvenile Atlantic cod across dietary treatments. Understanding the processes driving ecological assembly in the gut microbiome, in fish research specifically, could allow us to manipulate the microbiome for improved health or resilience to disease for improved aquaculture welfare and production.

BACKGROUND: High-quality peritoneal dialysis (PD) catheter insertion pathways are essential for optimal access to the therapy. Dialysis outcomes are influenced by a range of patient and center-related factors, and there is a need to better understand these so that catheter insertion pathways can be better matched to individual circumstances. OBJECTIVES: To examine how patient- and center-related factors influence the choice of catheter insertion pathways for a PD patient, and the impact of such factors and pathways on patient outcomes, and specifically, to compare the occurrence of and recovery from PD catheter-related adverse events and mortality in individuals who had surgical catheter insertion with those who had medical catheter insertion, and evaluate health economics. STUDY DESIGN: A prospective multi-center cohort study of incident PD patients at catheter insertion. This is an ancillary study nested within the International Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS). METHODS: Patients will be recruited during a 30-month recruitment period at 45 United Kingdom (UK) renal facilities, with a minimum 12-month follow-up. A graphical Markov model will be fitted to describe the associations between patient demographics, comorbidities, and catheter insertion pathways that are not explained by center practices and their impact on the occurrence of catheter-related adverse events, and patient-reported outcomes. The model will also explore the extent to which the catheter insertion pathway is determined by the center practice patterns, accounting for patient mix. Multi-state models will compare the rate of occurrence of a PD catheter-related adverse event, recovery from this, and mortality in individuals who had surgical catheter insertion compared with those who had medical catheter insertion, accounting for competing events, and adjusting for patient and center factors. A health economics evaluation will establish which, if any, catheter insertion pathway is superior in terms of cost effectiveness. DISCUSSION: The study will provide information on which catheter insertion pathways are better according to individual characteristics and whether it is acceptable for dialysis units to rely on a single catheter insertion technique or whether they should invest in developing flexible pathways that incorporate both medical and surgical PD catheter insertion techniques.

The Mississippian Strathclyde Group of the Midland Valley of Scotland yields some of the earliest non-marine ostracods. The succession records shallow marine, deltaic, estuarine, lagoonal, lacustrine, fluvial and swamp environments representing a series of staging-posts between fully marine and limnetic settings. Macrofossils and ostracods are assigned to marine, marginal marine, brackish and freshwater environments based on their faunal assemblage patterns. Key brackish to freshwater ostracods are Geisina arcuata, Paraparchites circularis n. sp., Shemonaella ornata n. sp. and Silenites sp. A, associated with the bivalves Anthraconaia, Carbonicola, Cardiopteridium, Curvirimula, Naiadites, the microconchid ‘Spirorbis’, Spinicaudata and fish. Many Platycopina and Paraparchiticopina ostracods are interpreted as euryhaline, which corresponds with their occurrence in marine to coastal plain water bodies, and supports the ‘estuary effect’ hypothesis of non-marine colonization. The success of non-marine colonization by ostracods was dependent on the intrinsic adaptations of ostracod species to lower salinities, such as new reproductive strategies and the timing of extrinsic mechanisms to drive non-marine colonization, such as sea-level change. The genus Carbonita is the oldest and most common freshwater ostracod, and went on to dominate freshwater environments in the Late Palaeozoic.

Background: During the pre-patent stage of infection, juvenile Schistosoma blood flukes co-opt signals from the adaptive immune system to facilitate parasite development, but the types of responses that are induced at this early stage of infection, and the parasite antigens they target, have not been characterized. Results: Through analysis of experimental pre-patent infections, we show that the S. mansoni cysteine protease SmCB1 is rapidly targeted by an antigen-specific IgE response. The induction of this response is independent of schistosome eggs as infection with male or female worms alone also induced SmCB1-specific IgE. We also show that the SmCB1-specific IgE response is dependent on cognate CD4(+) T cell help and IL-4, suggesting that prepatent Th2 responses provide T cell help for the SmCB1-specific IgE response. Finally, exposed human subjects also produced IgE against SmCB1. Conclusions: Our data demonstrate that, like eggs, schistosome worms also induce functional type 2 responses and that a parasite cysteine protease is an inducer of type 2 responses during the early stages of schistosome infection.

Se describe en sistema de enseñanza superior de ingeniería británico en los años cuarenta, enumerando los conocimientos y condiciones que se exigen a los ingenieros recién licenciados. Este sistema educativo admite una considerable flexibilidad y da gran importancia a la parte práctica en los estudios. Su gran desarrollo es uno de los principales motivos de los progresos científicos y el desenvolvimiento industrial de la época. Ministerio Educación CIDE Biblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; biblioteca@mecd.es ESP

Lake sediments have the potential to preserve proxy records of past climate change. Organic material suitable for radiocarbon dating often provides age control of such proxy records. Six shallow freshwater lakes on the sub-Antarctic island of South Georgia were investigated for carbon reservoir effects that may influence age-depth profiles from lake sediment records in this important region. Paired samples of particulate organic matter (POM) from the water column and surface sediment (bulk organic carbon) were analyzed by accelerator mass spectrometry C-14. POM in 4 lakes was found to be in equilibrium with the atmosphere (similar to107% modern), whereas 2 lakes showed significant depletion of 14C. In each lake, the surface sediment ages were older than the paired POM age. Surface sediment ages showed a much greater range of ages compared to the equivalent POM ages, even for lakes located in close proximity. We conclude that sediment disturbance during coring, bioturbation, and periodic resuspension of sediments are likely factors causing the difference in the apparent age of surface sediments.