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Decay rates for sunlight inactivation of polymerase chain reaction (PCR) markers for total Bacteroidales, human-specific Bacteroidales, Escherichia coli, and Bifidobacterium adolescentis relative to cultured £. coli were investigated. The experiment used 100-L chambers of fresh water and seawater (paired with dark controls) seeded with human sewage and exposed to natural sunlight over three summer days. Culturable E. coli levels in sunlight-exposed chambers decreased by at least 3 logs on day 1, and by day 3 a total reduction of 4.5 to 5.5 logs was achieved in fresh water and seawater, respectively. In contrast, PCR detection of the four gene targets in sunlight-exposed chambers reduced by no more than 2 logs over the duration of the study (kt < 0.071 loge units h-1). Under these experimental conditions, PCR markers are considerably more conservative than culturable E. coli and can persist for extended periods of time following inactivation of E. coli [ABSTRACT FROM AUTHOR]

We provide evidence for the origin of sexual individuals from parthenogenetic progenitors in natural populations. We demonstrate that this reversal has occurred independently in three geographically separated populations of the Asteraceous polyploid, Hieracium pilosella. We used chromosome counts and flow cytometry to determine ploidy and crossing experiments and flow cytometry to confirm sexuality. Inter-simple sequence repeat and allozyme markers demonstrated that the sexuals at each site were more closely related to their parthenogenetic neighbors than to sexuals at other sites. The same markers were used to estimate levels of ramet diversity, which were equally high among the parthenogens and sexuals. The observation that sexuals were always tetraploid is possibly explained by their having arisen through a rare sexual event, the fusion of two reduced (2x) gametes from pentaploid, facultatively apomictic parents. Such a reversal from almost total clonality to obligate sexual reproduction is unusual, and further work will determine whether the sexuals are in evolutionary equilibrium, are increasing at the expense of asexuals, or are simply surviving because of a lack of negative selection pressure. [ABSTRACT FROM AUTHOR]

Thirty on-site greywater systems were sampled to determine greywater characteristics and practices in the field. Kitchen greywater was present at eight sites and urine was included at seven sites. These non-traditional sources resulted in significantly higher concentrations of enterococci and 5-day biochemical oxygen demand (BOD5) in greywater. Even with the removal of these sources, the concentrations of microbial indicators indicated high levels of contamination could occur across all greywater sources, including "light" greywater. Using multiple microbial indicators showed that all samples had the potential for faecal contamination. Bacteroidales markers were confirmed in treated greywater and in each greywater source, highlighting the potential for human faecal contamination. Although Escherichia coli was absent in treated greywater recycled to the house, other microbial indicators were present; hence, caution is required in using E. coli concentrations as the sole indicator of microbiological water quality. High BOD5 or total suspended solid concentrations exceeded the levels recommended for effective disinfection. Subsurface irrigation, which is assumed to provide a five-log reduction in exposure, is a suitable reuse option for non-disinfected greywater. Only half the occupants had a good understanding of their greywater systems and 25 % of systems were poorly maintained. Elevated microbial indicator contamination of greywater sludge is a potential hazard during maintenance. [ABSTRACT FROM AUTHOR]