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Accumulation of plastics in the marine environment has widespread detrimental consequences for ecosystems and wildlife. Marine plastics are rapidly colonised by a wide diversity of bacteria, including human pathogens, posing potential risks to human health. Here, we investigate the effect of polymer type, residence time and estuarine location on bacterial colonisation of common household plastics, including pathogenic bacteria. To do so, we submerged five main household plastic types: low-density PE (LDPE), high-density PE (HDPE), polypropylene (PP), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) at an estuarine site in Cornwall (U.K.) and tracked bacterial colonisation dynamics. Using both culture-dependent and culture-independent approaches, we found that bacteria rapidly colonised plastics irrespective of polymer type. While biofilm community composition changed with colonisation time, no difference was observed between polymer types. Likewise, the presence of pathogenic bacteria, quantified using the insect model Galleria mellonella, increased over a five-week period, with no consistent differences observed between polymer types. Pathogens isolated from plastic biofilms using Galleria enrichment included Serratia and Enterococcus species and harboured a wide range of antimicrobial resistance genes. Our findings show that plastics in coastal waters are rapidly colonised by a wide diversity of bacteria, including known human pathogens, independent of polymer type.

Cyclic feeding schedules are now commonly used in conjunction with closed enteral feeding systems. Some manufacturers and clinicians have speculated that closed system cyclic feeding may promote formula contamination via retrograde movement of bacteria during the "no-flow" periods. Using both laboratory and clinical settings, our study evaluated whether retrograde bacterial movement under "no-flow" conditions results in contamination of closed system feeding containers. The clinical phase was conducted with 57 closed system feeding containers used to feed nursing home residents. In both laboratory and clinical testing there was no evidence of container contamination at 36-48 h, nor was there evidence of retrograde movement of bacteria beyond the drip chamber. Formula waste and costs were also analyzed using several 24- or 36-h hang time scenarios. Provided the appropriate container size is used, potential cost savings between $67 to $135 per patient per month may be achieved with the 36-h hang time scenarios. Retrograde movement of bacteria does not appear to be a source of closed system feeding container contamination in systems that incorporate a drip chamber. Using the appropriate size feeding container and systems with at least a 36-h hang time will result in significant cost savings.

Human African trypanosomiasis is caused by two subspecies of Trypanosoma brucei. Trypanosoma brucei rhodesiense is found in East Africa and frequently causes acute disease, while Trypanosoma brucei gambiense is found in West Africa and is associated with chronic disease. Samples taken from a single focus of a Ugandan outbreak of T. b. rhodesiense in the 1980s were associated with either chronic or acute disease. We sequenced the whole genomes of two of these isolates, which showed that they are genetically distinct from each other. Analysis of single nucleotide polymorphism markers in a panel of 31 Ugandan isolates plus 32 controls revealed a mixture of East African and West African haplotypes, and some of these haplotypes were associated with the different virulence phenotypes. It has been shown recently that T. b. brucei and T. b. rhodesiense populations undergo genetic exchange in natural populations. Our analysis showed that these strains from the Ugandan epidemic were intermediate between the reference genome sequences of T. b. gambiense and T. b. brucei and contained haplotypes that were present in both subspecies. This suggests that the human-infective subspecies of T. brucei are not genetically isolated, and our data are consistent with genomic introgression between East African and West African T. b. brucei subspecies. This has implications for the control of the parasite, the spread of drug resistance, and understanding the variation in virulence and the emergence of human infectivity., IMPORTANCE We present a genetic study of the acute form of “sleeping sickness” caused by the protozoan parasite Trypanosoma brucei rhodesiense from a single outbreak in Uganda. This represents an advance in our understanding of the relationship between the T. b. rhodesiense and Trypanosoma brucei gambiense subspecies that have previously been considered geographically distinct. Our data suggest that introgression of West African-derived T. brucei haplotypes may be associated with differences in disease presentation in the East African disease. These findings are not only of scientific interest but also important for parasite control, as they suggest that the human-infective T. brucei subspecies are not genetically isolated.

Map based cloning in Arabidopsis thaliana can be a difficult and time-consuming process, specifically if the phenotype is subtle and scoring labour intensive. Here, we have re-sequenced the 120-Mb genome of a novel Arabidopsis clock mutant early bird (ebi-1) in Wassilewskija (Ws-2). We demonstrate the utility of sequencing a backcrossed line in limiting the number of SNPs considered. We identify a SNP in the gene AtNFXL-2 as the likely cause of the ebi-1 phenotype.

The film of microalgae and macroalgal propagules which coats intertidal rocks is the main food resource of limpets, the dominant grazers on exposed shores of north-west Europe. Spatial and temporal variability in feeding activity of limpets and abundance of microalgae were examined at mid-tide level across a European gradient from the Isle of Man in the British Isles to south-west Portu- gal. Feeding activity was assessed as the frequency of radula scrapes on wax surfaces placed on the shore. This was undertaken monthly at 2 shores at each of 4 locations, the Isle of Man, south-west Eng- land, northern Spain and south-west Portugal, over 1 yr. The abundance of the microalgal film was de- termined simultaneously at 3 of the 4 locations by measuring the concentration of chlorophyll a on the rock surface. The density and species diversity of limpets increased with decreasing latitude. This was mirrored by a trend of increased levels of limpet grazing, although 1 location (northern Spain) did not fit this trend. Seasonal changes in limpet grazing intensity were found at 3 of the 4 locations, charac- terised by elevated grazing during the summer and autumn. The seasonal variations resulted from changes in the level of foraging of individual limpets and were positively correlated with mean sea temperature in the Isle of Man and south-west England. The pattern of grazing activity was not solely a function of sea temperature. In the Isle of Man, grazing by Patella vulgata declined during the later stages of gonad development and increased following spawning. Seasonal variation in the standing stock of microalgae, measured as the concentration of chlorophyll a, was found at all 3 locations ex- amined, the Isle of Man, south-west England and northern Spain, with greater abundance in the win- ter compared to summer. This pattern was consistent over both large (among locations: 100s of kilo- metres) and medium (between shores: 1000s of metres) scales. There were no correlations between microalgal abundance and limpet grazing activity at any location. There were significant negative cor- relations between chlorophyll a and maximum monthly air temperature and monthly sunshine hours. Comparison of microalgal abundance among locations showed a general decline in standing stock with decreasing latitude, but differences between specific locations varied with season. South-west England showed similar levels of microalgal abundance to the most northerly location (Isle of Man) in winter, and to the most southerly location (northern Spain) in the summer.

BACKGROUND: Entamoeba histolytica is a significant cause of disease worldwide. However, little is known about the genetic diversity of the parasite. We re-sequenced the genomes of ten laboratory cultured lines of the eukaryotic pathogen Entamoeba histolytica in order to develop a picture of genetic diversity across the genome. RESULTS: The extreme nucleotide composition bias and repetitiveness of the E. histolytica genome provide a challenge for short-read mapping, yet we were able to define putative single nucleotide polymorphisms in a large portion of the genome. The results suggest a rather low level of single nucleotide diversity, although genes and gene families with putative roles in virulence are among the more polymorphic genes. We did observe large differences in coverage depth among genes, indicating differences in gene copy number between genomes. We found evidence indicating that recombination has occurred in the history of the sequenced genomes, suggesting that E. histolytica may reproduce sexually. CONCLUSIONS: E. histolytica displays a relatively low level of nucleotide diversity across its genome. However, large differences in gene family content and gene copy number are seen among the sequenced genomes. The pattern of polymorphism indicates that E. histolytica reproduces sexually, or has done so in the past, which has previously been suggested but not proven.