Nitrogen fixation associated with sago (Metroxylon sagu) and some implications
- Shipton, Warren, Baker, Anthony, Blaney, Barry, Horwood, Paul, Warner, Jeffrey, Pelowa, Daniel, Greenhill, Andrew
- Authors: Shipton, Warren , Baker, Anthony , Blaney, Barry , Horwood, Paul , Warner, Jeffrey , Pelowa, Daniel , Greenhill, Andrew
- Date: 2011
- Type: Text , Journal article
- Relation: Letters in Applied Microbiology Vol. 52, no. 1 (2011), p. 56-61
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- Description: Aims: To determine the presence and contribution of diazotrophic bacteria to nitrogen concentrations in edible starch derived from the sago palm (Metroxylon sagu).Methods and Results: Isolation of diazotrophic bacteria and analysis of nitrogen fixation were conducted on pith, root and sago starch samples. Acetylene reduction showed that five of ten starch samples were fixing nitrogen. Two presumptive nitrogen-fixing bacteria from starch fixed nitrogen in pure culture and five isolates were positive for the nif H gene. Nitrogen concentrations in 51 starch samples were low (37 samples <0.2 g kg-1; 14 ranging from 0.2 to 2.0 g kg-1).Conclusions: Nitrogen fixation occurs in sago starch, which undoubtedly plays a role in fermentation ecology. Nitrogen levels are considered too low to be of nutritional benefit and to protect against nutritional-associated illnesses.Significance and Impact of the Study: Sago starch does not add significantly to the protein calorie intake and may be associated with susceptibility to nutritional-associated illness.
Molecular phylogeny of Burkholderia pseudomallei from a remote region of Papua New Guinea
- Baker, Anthony, Pearson, Talima, Price, Erin, Dale, Julia, Keim, Paul, Hornstra, Heidie, Greenhill, Andrew, Padilla, Gabriel, Warner, Jeffrey
- Authors: Baker, Anthony , Pearson, Talima , Price, Erin , Dale, Julia , Keim, Paul , Hornstra, Heidie , Greenhill, Andrew , Padilla, Gabriel , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 3 (2011), p.
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- Reviewed:
- Description: Background: The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales. Methodology/Principal Findings: We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability. Conclusions/Significance: Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.
- Authors: Baker, Anthony , Pearson, Talima , Price, Erin , Dale, Julia , Keim, Paul , Hornstra, Heidie , Greenhill, Andrew , Padilla, Gabriel , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 3 (2011), p.
- Full Text:
- Reviewed:
- Description: Background: The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales. Methodology/Principal Findings: We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability. Conclusions/Significance: Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.
Groundwater seeps facilitate exposure to Burkholderia pseudomallei
- Baker, Anthony, Tahani, Donald, Gardiner, Christopher, Bristow, Keith, Greenhill, Andrew, Warner, Jeffrey
- Authors: Baker, Anthony , Tahani, Donald , Gardiner, Christopher , Bristow, Keith , Greenhill, Andrew , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: Applied and Environmental Microbiology Vol. 77, no. 20 (2011), p. 7243-7246
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- Reviewed:
- Description: Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and water from seasonal groundwater seeps were collected around the base of Castle Hill and analyzed by quantitative real-time PCR targeting the type III secretion system genes for the presence of B. pseudomallei. The organism was identified in 65% (95% confidence interval [CI], 49.5 to 80.4) of soil samples (n =40) and 92.5% (95% CI, 83.9 to 100) of seasonal groundwater samples (n =40). Further sampling of water collected from roads and gutters in nearby residential areas after an intense rainfall event found that 88.2% (95% CI, 72.9 to 100) of samples (n =16) contained viable B. pseudomallei at concentrations up to 113 CFU/ml. Comparison of isolates using multilocus sequence typing demonstrated clinical matches and close associations between environmental isolates and isolates derived from clinical samples from patients in Townsville. This study demonstrated that waterborne B. pseudomallei from groundwater seeps around Castle Hill may facilitate exposure to B. pseudomallei and contribute to the clinical clustering at this site. Access to this type of information will advise the development and implementation of public health measures to reduce the incidence of melioidosis. © 2011, American Society for Microbiology.
- Authors: Baker, Anthony , Tahani, Donald , Gardiner, Christopher , Bristow, Keith , Greenhill, Andrew , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: Applied and Environmental Microbiology Vol. 77, no. 20 (2011), p. 7243-7246
- Full Text:
- Reviewed:
- Description: Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and water from seasonal groundwater seeps were collected around the base of Castle Hill and analyzed by quantitative real-time PCR targeting the type III secretion system genes for the presence of B. pseudomallei. The organism was identified in 65% (95% confidence interval [CI], 49.5 to 80.4) of soil samples (n =40) and 92.5% (95% CI, 83.9 to 100) of seasonal groundwater samples (n =40). Further sampling of water collected from roads and gutters in nearby residential areas after an intense rainfall event found that 88.2% (95% CI, 72.9 to 100) of samples (n =16) contained viable B. pseudomallei at concentrations up to 113 CFU/ml. Comparison of isolates using multilocus sequence typing demonstrated clinical matches and close associations between environmental isolates and isolates derived from clinical samples from patients in Townsville. This study demonstrated that waterborne B. pseudomallei from groundwater seeps around Castle Hill may facilitate exposure to B. pseudomallei and contribute to the clinical clustering at this site. Access to this type of information will advise the development and implementation of public health measures to reduce the incidence of melioidosis. © 2011, American Society for Microbiology.
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