A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Military uses of groundwater : a driver of innovation

Military need has been a positive driver to the development of the modern day, and now mature, science of hydrogeology. The important synergy between geology and water supply was appreciated by military men in the mid-nineteenth century but the first real test of this learning only took place in the First World War. German, British and American geologists then mapped water resources and the potential for exploiting groundwater in Belgium and northern France. Technical innovations included deployment of rapid drilling techniques and the promotion of well screens for use in unconsolidated sediments. The mapping techniques were developed further during the Second World War when innovative remote mapping of enemy-occupied territory became an important planning tool to both Allied and German armies. Work in North Africa and other arid and semi-arid terrains promoted insight into the occurrence of groundwater in fresh-water aquifers little replenished by recharge. Mapping of hard rock basement-type environments in the islands of Jersey and Guernsey by German geologists was a concept new to the British Isles. Collectively, these varied initiatives provided part of the foundation for post-Second World War development of modern-day applied hydrogeology

Host-specific adaptation governs the interaction of the marine diatom, Pseudo-nitzschia and their microbiota

The association of phytoplankton with bacteria is ubiquitous in nature and the bacteria that associate with different phytoplankton species are very diverse. The influence of these bacteria in the physiology and ecology of the host and the evolutionary forces that shape the relationship are still not understood. In this study, we used the Pseudo-nitzschia–microbiota association to determine (1) if algal species with distinct domoic acid (DA) production are selection factors that structures the bacterial community, (2) if host-specificity and co-adaptation govern the association, (3) the functional roles of isolated member of microbiota on diatom–hosts fitness and (4) the influence of microbiota in changing the phenotype of the diatom hosts with regards to toxin production. Analysis of the pyrosequencing-derived 16S rDNA data suggests that the three tested species of Pseudo-nitzschia, which vary in toxin production, have phylogenetically distinct bacterial communities, and toxic Pseudo-nitzschia have lower microbial diversity than non-toxic Pseudo-nitzschia. Transplant experiments showed that isolated members of the microbiota are mutualistic to their native hosts but some are commensal or parasitic to foreign hosts, hinting at co-evolution between partners. Moreover, Pseudo-nitzschia host can gain protection from algalytic bacteria by maintaining association with its microbiota. Pseudo-nitzschia also exhibit different phenotypic expression with regards to DA production, and this depends on the bacterial species with which the host associates. Hence, the influences of the microbiota on diatom host physiology should be considered when studying the biology and ecology of marine diatoms

Bacterial assembly and temporal dynamics in activated sludge of a full-scale municipal wastewater treatment plant

Understanding environmental and biological influences on the dynamics of microbial communities has received great attention in microbial ecology. Here, utilizing large time-series 16S rRNA gene data, we show that in activated sludge of an environmentally important municipal wastewater treatment plant, 5-year temporal dynamics of bacterial community shows no significant seasonal succession, but is consistent with deterministic assemblage by taxonomic relatedness. Biological interactions are dominant drivers in determining the bacterial community assembly, whereas environmental conditions (mainly sludge retention time and inorganic nitrogen) partially explain phylogenetic and quantitative variances and indirectly influence bacterial assembly. We demonstrate a correlation-based statistical method to integrate bacterial association networks with their taxonomic affiliations to predict community-wide co-occurrence and co-exclusion patterns. The results show that although taxonomically closely related bacteria tend to positively co-occur (for example, out of a cooperative relationship), negative co-excluding correlations are deterministically observed between taxonomically less related species, probably implicating roles of competition in determining bacterial assembly. Overall, disclosures of the positive and negative species–species relations will improve our understanding of ecological niches occupied by unknown species and help to predict their biological functions in ecosystems

A meta-analysis of changes in bacterial and archaeal communities with time

Ecologists have long studied the temporal dynamics of plant and animal communities with much less attention paid to the temporal dynamics exhibited by microbial communities. As a result, we do not know if overarching temporal trends exist for microbial communities or if changes in microbial communities are generally predictable with time. Using microbial time series assessed via high-throughput sequencing, we conducted a meta-analysis of temporal dynamics in microbial communities, including 76 sites representing air, aquatic, soil, brewery wastewater treatment, human- and plant-associated microbial biomes. We found that temporal variability in both within- and between-community diversity was consistent among microbial communities from similar environments. Community structure changed systematically with time in less than half of the cases, and the highest rates of change were observed within ranges of 1 day to 1 month for all communities examined. Microbial communities exhibited species–time relationships (STRs), which describe the accumulation of new taxa to a community, similar to those observed previously for plant and animal communities, suggesting that STRs are remarkably consistent across a broad range of taxa. These results highlight that a continued integration of microbial ecology into the broader field of ecology will provide new insight into the temporal patterns of microbial and ‘macro'-bial communities alike