Amixicile, a novel strategy for targeting oral anaerobic pathogens

The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

Utility of field-based techniques to assess Indigenous Australians' functional fitness and sedentary time

OBJECTIVE

To examine the utility of field-based techniques to assess functional exercise capacity and sedentary time in Indigenous and non-Indigenous regional Australian adults.

STUDY DESIGN

Observational, analytic cohort study.

METHODS

Ninety six adults residing in regional and remote Australian communities participated in this study (Indigenous n = 61 and non-Indigenous Australians n = 35). Participants undertook a field-based test of functional exercise capacity (6 min walk test; 6 MWT) and wore an accelerometer during waking hours for seven days, provided self-report data on physical activity and sedentary time and rated experiences in regard to the ease of complying with study protocols.

RESULTS

There were high levels of compliance in this study (Indigenous: 91% and non-Indigenous: 97%). Functional exercise capacity was lower in Indigenous Australians (P < 0.001), and independently associated with advancing age, higher BMI, and indigeneity, with 45% of variability in the 6 MWT distance explained by these factors. The relationship between accelerometer and self-report measures of sedentary behaviour was significant (P < 0.001) but only explained 17% of the total variation.

CONCLUSIONS

This study demonstrated very good compliance for the methods utilised and is the first to report reduced functional exercise capacity in Indigenous people.

IMPLICATIONS

The field-based techniques from this study demonstrate good utility for larger scale implementation in regional Indigenous populations.

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists.

Self-reported health benefits in patients recruited into New Zealand's 'Green Prescription' primary health care program

To assess the effectiveness of the 'Green Prescription' (GRx) program in promoting self-reported health benefits in previously inactive individuals, between 2001 and 2002, a retrospective survey was administered to 124 GRx patients throughout New Zealand. Participants were a non-randomized subset of a larger GRx population. Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for differences in health outcomes between participants who had increased physical activity levels compared to participants who had decreased or not altered activity levels since first being prescribed the GRx. Completed surveys were obtained from 124 of 263 eligible participants; a response rate of 47%. Fifty-six percent of participants reported increases in physical activity levels after the GRx program, with 70% still undertaking some form of physical activity. Participants accumulated at least 30 minutes of physical activity per day on 3.4 +/- 2.5 days (mean +/- SD) per week. Participants who reported increased physical activity levels after the GRx reported substantially higher energy levels and improved breathing when compared to participants who reported less or about the same physical activity after the GRx intervention. Increased physical activity in GRx patients was associated with greater perceived health benefits. Effective and ongoing support networks were seen as important for behavior change.