Phages of Bacteroides (GB-124): a novel tool for viral waterborne disease control?

Current fecal indicator bacteria (FIB) and emerging microbial source tracking (MST) methods may indicate the presence and even the likely source of water contamination, but they are less effective at determining the potential risk to health from human enteric viruses. This paper investigates the presence of human-specific phages (detected using a low-cost MST method) in municipal wastewaters (MW) and assesses whether they may be used effectively to screen for the likely presence of human adenovirus (HAdV) and norovirus (NoV). The findings demonstrated that all samples positive for HAdV and/or NoV also contained phages infecting Bacteroides GB-124 (mean = 4.36 log(10) PFU/100 mL) and that GB-124 phages, HAdV, and NoV were absent from samples of nonhuman origin. HAdV and NoV were detected more frequently in MW samples containing higher levels of phages (e.g., >10(2)) and FIB (e.g., >10(3)). Interestingly, at one sewage treatment works (STW), the levels of GB-124 phages present in treated MW were not significantly lower (p = 0.001) than those in untreated MW. There was a positive correlation (R = 0.42) between the size of STW and the number of GB-124 phages present in the final treated effluent. Therefore, the detection of GB-124 phages by a simple phage-lysis method may have considerable potential as a low-cost surrogate for the detection of certain human pathogenic viruses in MW and receiving waters.

Application of the heteroduplex mobility assay (HMA) for the investigation of the genomic diversity among noroviruses in environmental samples.

Recent studies have demonstrated the widespread contamination of river and seawater with noroviruses (NV), often with more than one strain. The heteroduplex mobility assay (HMA) in which amplicons from study samples are hybridised (by denaturing and reannealing) to amplicons from reference strains and resolved by electrophoresis, has the potential to provide a simple and rapid means to identify samples containing multiple NV strains and to establish the diversity of strains within that sample. PCR amplicons from environmental samples that were tested directly in the HMA assay were shown to contain more than one strain. In order to evaluate HMA for investigations of NV diversity in environmental samples, amplicons from three representative samples were cloned and, for each, 20 amplicons derived from individual clones were analysed by HMA. Between two and six different HMA profiles were demonstrated among clones from a single sample indicating the extent of NV diversity in the sample. Sequence analysis confirmed the relationship of HMA profile and NV 'genotype'. Far greater diversity was seen among Genogroup (G) II (Ni/E3) amplicons than Genogroup (G) I (Ando/E3) amplicons (generated from the RNA dependent RNA polymerase region of the ORF1 of noroviruses), which often contained only a single strain, which is reflective of the greater prevalence of GII NVs over GI NVs. Overall, four GII and four GI strains were identified in these environmental water/sewage samples.

Relative Effectiveness of Reading Intervention Programs for Adults with Low Literacy.

To compare the efficacy of instructional programs for adult learners with basic reading skills below the seventh grade level, 300 adults were randomly assigned to one of three supplementary tutoring programs designed to strengthen decoding and fluency skills, and gains were examined for the 148 adult students who completed the program. The three intervention programs were based on or adapted from instructional programs that have been shown to benefit children with reading levels similar to those of the adult sample. Each program varied in its relative emphasis on basic decoding versus reading fluency instruction. A repeated measures MANOVA confirmed small to moderate reading gains from pre- to post-testing across a battery of targeted reading measures, but no significant relative differences across interventions. An additional 152 participants who failed to complete the intervention differed initially from those who persisted. Implications for future research and adult literacy instruction are discussed.

Relationships among reading skills of adults with low literacy.

In this study, confirmatory factor analyses were used to examine the interrelationships among latent factors of the simple view model of reading comprehension (word recognition and language comprehension) and hypothesized additional factors (vocabulary and reading fluency) in a sample of 476 adult learners with low literacy levels. The results provided evidence for reliable distinctions between word recognition, fluency, language comprehension, and vocabulary skills as components of reading. Even so, the data did not support the hypothesis that the simple view needs to be expanded to include vocabulary or fluency factors, as has been posited in a few prior studies of younger and more able readers. Rather, word recognition and language comprehension alone were found to account adequately for variation in reading comprehension in adults with low literacy.