Composition and Distribution of Extracellular Polymeric Substances in Aerobic Flocs and Granular Sludge

Extracellular polymeric substances (EPS) were quantified in flocculent and aerobic granular sludge developed in two sequencing batch reactors with the same shear force but different settling times. Several EPS extraction methods were compared to investigate how different methods affect EPS chemical characterization, and fluorescent stains were used to visualize EPS in intact samples and 20-µm cryosections. Reactor 1 (operated with a 10-min settle) enriched predominantly flocculent sludge with a sludge volume index (SVI) of 120 ± 12 ml g–1, and reactor 2 (2-min settle time) formed compact aerobic granules with an SVI of 50 ± 2 ml g–1. EPS extraction by using a cation-exchange resin showed that proteins were more dominant than polysaccharides in all samples, and the protein content was 50% more in granular EPS than flocculent EPS. NaOH and heat extraction produced a higher protein and polysaccharide content from cell lysis. In situ EPS staining of granules showed that cells and polysaccharides were localized to the outer edge of granules, whereas the center was comprised mostly of proteins. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on a noncellular, protein core. The comparison of EPS methods explains how significant cell lysis and contamination by dead biomass leads to different and opposing conclusions

Pan-Arctic Analysis of Cultural Ecosystem Services Using Social Media and Automated Content Analysis

In the Arctic, as in many parts of the world, interactions with the natural world are an important part of people\u27s experience and are often recorded in photographs. Emerging methods for automated content analysis of social media data offers opportunities to discover information on cultural ecosystem services from photographs across large samples of people and countries. We analysed over 800,000 Flickr photographs using Google\u27s Cloud Vision algorithm to identify the components of the natural environment most photographed and to map how and where different people interact with nature across eight Arctic countries. Almost all (91.1%) of users took one or more photographs of biotic nature, and such photos account for over half (53.2%) of Arctic photos on Flickr. We find that although the vast majority of Arctic human-nature interactions occur outside protected areas, people are slightly more likely to photograph nature inside protected areas after accounting for the low accessibility of Arctic protected areas. Wildlife photographers travel further from roads than people who take fewer photographs of wildlife, and people venture much further from roads inside protected areas. A large diversity of nature was reflected in the photographs, from mammals, birds, fish, fungi, plants and invertebrates, signalling an untapped potential to connect and engage people in the appreciation and conservation of the natural world. Our findings suggest that, despite limitations, automated content analysis can be a rapid and readily accessed source of data on how and where people interact with nature, and a large-scale method for assessing cultural ecosystem services across countries and cultures

Scale-dependent response diversity of seabirds to prey in the North Sea

Functional response diversity is defined as the diversity of responses to environmental change among species that contribute to the same ecosystem function. Because different ecological processes dominate on different spatial and temporal scales, response diversity is likely to be scale dependent. Using three extensive data sets on seabirds, pelagic fish, and zooplankton, we investigate the strength and diversity in the response of seabirds to prey in the North Sea over three scales of ecological organization. Two-stage analyses were used to partition the variance in the abundance of predators and prey among the different scales of investigation: variation from year to year, variation among habitats, and variation on the local patch scale. On the year-to-year scale, we found a strong and synchronous response of seabirds to the abundance of prey, resulting in low response diversity. Conversely, as different seabird species were found in habitats dominated by different prey species, we found a high diversity in the response of seabirds to prey on the habitat scale. Finally, on the local patch scale, seabirds were organized in multispecies patches. These patches were weakly associated with patches of prey, resulting in a weak response strength and a low response diversity. We suggest that ecological similarities among seabird species resulted in low response diversity on the year-to-year scale. On the habitat scale, we suggest that high response diversity was due to interspecific competition and niche segregation among seabird species. On the local patch scale, we suggest that facilitation with respect to the detection and accessibility of prey patches resulted in overlapping distribution of seabirds but weak associations with prey. The observed scale dependencies in response strength and diversity have implications for how the seabird community will respond to different environmental disturbances

Cell-seeded thermoreversible hydrogel-polyurethane composites for nucleus pulposus augmentation

Tissue engineering represents an alternative approach to the current invasive surgical procedures for the intervertebral disc (IVD) repair. The combination of injectable hydrogels and elastic biomaterials allow three-dimensional cell cultures and provide mechanical stability. In the present study a thermoreversible hyaluronan (HA) hydrogel as well as fibrin glue were mixed with polyurethane (PU) and their effect was investigated on the proliferation and differentiation of human IVD (hIVD cells) and mesenchymal stem cells (hMSCs) by in vitro and ex-vivo experiments

A flow cell simulating a subsurface rock fracture for investigations of groundwater-derived biofilms

Laboratory scale continuous-flow-through chambers (flow cells) facilitate the observation of microbes in a controlled, fully hydrated environment, although these systems often do not simulate the environmental conditions under which microorganisms are found. We developed a flow cell that mimics a subsurface groundwater-saturated rock fracture and isamenable to confocal laser scanning microscopy while allowing for the simple removal of the attached biomass. This flow cell was used to investigate the effect of toluene, a representative contaminant for non-aqueous phase liquids, on groundwater-derived biofilms. Reduced average biofilm biomass and thickness, and diminished diversity of amplifiable 16S rRNA sequences were observed for biofilms that developed in the presence of toluene, compared to the biofilms grown in the absence of toluene. The flow cell also allowed the detection of fluorescent protein-labelled cells

Buoyant densities of DNA from various strains of Streptococcus mutans

The buoyant densities of eight strains of Streptococcus mutans were determined by analytical ultracentrifugation in caesium chloride. The results were as follows (in g/cm3): K-1-R(1.7044); SL-1(1.7040); E-49(1.7010); BHT(1.7009); FA-1(1.7000); Ingbritt(1.6967); NCTC-10449(1.6964); GS-5(1.6962). These data add to the mounting evidence for genetic heterogeneity in Strept. mutans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34097/1/0000379.pd

Ongoing outbreaks of hepatitis A among men who have sex with men (MSM), Berlin, November 2016 to January 2017 – linked to other German cities and European countries

Since 14 November 2016, 38 cases of hepatitis A have been notified in Berlin; of these, 37 were male and 30 reported to have sex with men (MSM). Median age of MSM cases is 31 years (range: 24–52 years). Phylogenetic analysis revealed three distinct sequences, linking cases in Berlin to those in other German cities and to clusters recognised in other European countries in 2016