Alison Ling - Academia.edu (original) (raw)

Papers by Alison Ling

Research paper thumbnail of Bacterial Bioaerosol Enrichment Downwind from a Conventional Wastewater Aeration Basin Manifests from Selective Actinomycete Partitioning

Over a period of eleven days, size segregated aerosols were collected in consecutive 24 hour samp... more Over a period of eleven days, size segregated aerosols were collected in consecutive 24 hour sampling campaigns; these were concurrently executed upwind and downwind of a conventional activated sludge wastewater treatment plant. Airborne particulate matter was separated by mean aerodynamic diameter and continually impacted on polycarbonate filters, which were subsequently extracted with ethanol and chloroform to isolate and purify DNA. As judged by analyses of 16s rDNA sequences from an Illumina Miseq platform, airborne bacteria immediately downwind from the aeration basin was enriched with Actinomycetes when compared to the airborne microbes recovered upwind of this site. Concurrent DNA analyses of the activated sludge suggest that the aerated wastewater was the source of airborne Actinomycetes, and that selected genera were selectively partitioning into a local bioaerosol which included, but was not limited to, Mycobacteria spp., Saccaropolyspora spp., and Streptomyces spp.. These...

Research paper thumbnail of Carbon Dioxide and Hydrogen Sulfide Associations with Regional Bacterial Diversity Patterns in Microbially Induced Concrete Corrosion

Environmental Science & Technology, 2014

The microbial communities associated with deteriorating concrete corrosion fronts were characteri... more The microbial communities associated with deteriorating concrete corrosion fronts were characterized in 35 samples taken from wastewater collection and treatment systems in ten utilities. Bacterial communities were described using Illumina MiSeq sequencing of the V1V2 region of the small subunit ribosomal ribonucleic acid (SSU-rRNA) gene recovered from fresh corrosion products. Headspace gas concentrations (hydrogen sulfide, carbon dioxide, and methane), pore water pH, moisture content, and select mineralogy were tested for correlation to community outcomes and corrosion extent using pairwise linear regressions and canonical correspondence analysis. Corroding concrete was most commonly characterized by moisture contents greater than 10%, pore water pH below one, and limited richness (<10 taxa). Bacterial community composition was not correlated to geographic location when considered independently from other environmental factors. Corrosion was most severe in sites with high levels of hydrogen sulfide (>100 ppm) and carbon dioxide (>1%) gases, conditions which also were associated with low diversity biofilms dominated by members of the acidophilic sulfur-oxidizer genus Acidithiobacillus.

Research paper thumbnail of Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

Journal of Power Sources, 2010

Activated carbon fiber felt Non-catalyst cathode Upflow microbial fuel cell a b s t r a c t An ac... more Activated carbon fiber felt Non-catalyst cathode Upflow microbial fuel cell a b s t r a c t An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m −2 , compared to lower values with cathodes made of plain carbon paper (67 mW m −2 ), carbon felt (77 mW m −2 ), or platinum-coated carbon paper (124 mW m −2 , 0.2 mg-Pt cm −2 ). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm −2 ) increases the maximum power density to 391 mW m −2 . Power production is further increased to 784 mW m −2 by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m −2 (0.5 cm granules), and 667 mW m −2 (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst.

Research paper thumbnail of Tetracycline Resistance and Class 1 Integron Genes Associated with Indoor and Outdoor Aerosols

Environmental Science & Technology, 2013

Genes encoding tetracycline resistance and the integrase of Class 1 integrons were enumerated usi... more Genes encoding tetracycline resistance and the integrase of Class 1 integrons were enumerated using quantitative PCR from aerosols collected from indoor and outdoor environments. Concentrated animal feeding operations (CAFOs) and human-occupied indoor environments (two clinics and a homeless shelter) were found to be a source of airborne tet(X) and tet(W) genes. The CAFOs had 10- to 100-times higher concentrations of airborne 16S rRNA, tet(X), and tet(W) genes than other environments sampled, and increased concentrations of aerosolized bacteria correlated with increased concentrations of airborne resistance genes. The two CAFOs studied had statistically similar concentrations of resistance genes in their aerosol samples, even though antibiotic use was markedly different between the two operations. Additionally, tet(W) genes were recovered in outdoor air within 2 km of livestock operations, which suggests that antibiotic resistance genes may be transported via aerosols on local scales. The integrase gene (intI1) from Class 1 integrons, which has been associated with multidrug resistance, was detected in CAFOs but not in human-occupied indoor environments, suggesting that CAFO aerosols could serve as a reservoir of multidrug resistance. In conclusion, our results show that CAFOs and clinics are sources of aerosolized antibiotic resistance genes that can potentially be transported via air movement.

Research paper thumbnail of GENOME ANALYSIS AND MARKERS

Cruciferae Newsletter, 2008

Canola (Brassica napus) is an economically important crop in Australia, supplying 13% of the worl... more Canola (Brassica napus) is an economically important crop in Australia, supplying 13% of the world demand for canola oil. Blackleg, caused by Leptosphaeria maculans is the most damaging disease affecting canola. In Australia highly virulent pathotypes predominate, leading to annual yield loss 10-15% with much greater losses, of up to 100%, observed during some years. We have developed gene expression microarray technology to examine changes in gene expression associated with blackleg infection in canola. Over 20,000 ...

Research paper thumbnail of High-Resolution Microbial Community Succession of Microbially Induced Concrete Corrosion in Working Sanitary Manholes

PLOS ONE, 2015

Microbially-induced concrete corrosion in headspaces threatens wastewater infrastructure worldwid... more Microbially-induced concrete corrosion in headspaces threatens wastewater infrastructure worldwide. Models for predicting corrosion rates in sewer pipe networks rely largely on information from culture-based investigations. In this study, the succession of microbes associated with corroding concrete was characterized over a one-year monitoring campaign using rRNA sequence-based phylogenetic methods. New concrete specimens were exposed in two highly corrosive manholes (high concentrations of hydrogen sulfide and carbon dioxide gas) on the Colorado Front Range for up to a year. Community succession on corroding surfaces was assessed using Illumina MiSeq sequencing of 16S bacterial rRNA amplicons and Sanger sequencing of 16S universal rRNA clones. Microbial communities associated with corrosion fronts presented distinct succession patterns which converged to markedly low α-diversity levels (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 10 taxa) in conjunction with decreasing pH. The microbial community succession pattern observed in this study agreed with culture-based models that implicate acidophilic sulfur-oxidizer Acidithiobacillus spp. in advanced communities, with two notable exceptions. Early communities exposed to alkaline surface pH presented relatively high α-diversity, including heterotrophic, nitrogen-fixing, and sulfur-oxidizing genera, and one community exposed to neutral surface pH presented a diverse transition community comprised of less than 20% sulfur-oxidizers.

Research paper thumbnail of Bacterial Bioaerosol Enrichment Downwind from a Conventional Wastewater Aeration Basin Manifests from Selective Actinomycete Partitioning

Over a period of eleven days, size segregated aerosols were collected in consecutive 24 hour samp... more Over a period of eleven days, size segregated aerosols were collected in consecutive 24 hour sampling campaigns; these were concurrently executed upwind and downwind of a conventional activated sludge wastewater treatment plant. Airborne particulate matter was separated by mean aerodynamic diameter and continually impacted on polycarbonate filters, which were subsequently extracted with ethanol and chloroform to isolate and purify DNA. As judged by analyses of 16s rDNA sequences from an Illumina Miseq platform, airborne bacteria immediately downwind from the aeration basin was enriched with Actinomycetes when compared to the airborne microbes recovered upwind of this site. Concurrent DNA analyses of the activated sludge suggest that the aerated wastewater was the source of airborne Actinomycetes, and that selected genera were selectively partitioning into a local bioaerosol which included, but was not limited to, Mycobacteria spp., Saccaropolyspora spp., and Streptomyces spp.. These...

Research paper thumbnail of Carbon Dioxide and Hydrogen Sulfide Associations with Regional Bacterial Diversity Patterns in Microbially Induced Concrete Corrosion

Environmental Science & Technology, 2014

The microbial communities associated with deteriorating concrete corrosion fronts were characteri... more The microbial communities associated with deteriorating concrete corrosion fronts were characterized in 35 samples taken from wastewater collection and treatment systems in ten utilities. Bacterial communities were described using Illumina MiSeq sequencing of the V1V2 region of the small subunit ribosomal ribonucleic acid (SSU-rRNA) gene recovered from fresh corrosion products. Headspace gas concentrations (hydrogen sulfide, carbon dioxide, and methane), pore water pH, moisture content, and select mineralogy were tested for correlation to community outcomes and corrosion extent using pairwise linear regressions and canonical correspondence analysis. Corroding concrete was most commonly characterized by moisture contents greater than 10%, pore water pH below one, and limited richness (<10 taxa). Bacterial community composition was not correlated to geographic location when considered independently from other environmental factors. Corrosion was most severe in sites with high levels of hydrogen sulfide (>100 ppm) and carbon dioxide (>1%) gases, conditions which also were associated with low diversity biofilms dominated by members of the acidophilic sulfur-oxidizer genus Acidithiobacillus.

Research paper thumbnail of Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

Journal of Power Sources, 2010

Activated carbon fiber felt Non-catalyst cathode Upflow microbial fuel cell a b s t r a c t An ac... more Activated carbon fiber felt Non-catalyst cathode Upflow microbial fuel cell a b s t r a c t An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m −2 , compared to lower values with cathodes made of plain carbon paper (67 mW m −2 ), carbon felt (77 mW m −2 ), or platinum-coated carbon paper (124 mW m −2 , 0.2 mg-Pt cm −2 ). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm −2 ) increases the maximum power density to 391 mW m −2 . Power production is further increased to 784 mW m −2 by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m −2 (0.5 cm granules), and 667 mW m −2 (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst.

Research paper thumbnail of Tetracycline Resistance and Class 1 Integron Genes Associated with Indoor and Outdoor Aerosols

Environmental Science & Technology, 2013

Genes encoding tetracycline resistance and the integrase of Class 1 integrons were enumerated usi... more Genes encoding tetracycline resistance and the integrase of Class 1 integrons were enumerated using quantitative PCR from aerosols collected from indoor and outdoor environments. Concentrated animal feeding operations (CAFOs) and human-occupied indoor environments (two clinics and a homeless shelter) were found to be a source of airborne tet(X) and tet(W) genes. The CAFOs had 10- to 100-times higher concentrations of airborne 16S rRNA, tet(X), and tet(W) genes than other environments sampled, and increased concentrations of aerosolized bacteria correlated with increased concentrations of airborne resistance genes. The two CAFOs studied had statistically similar concentrations of resistance genes in their aerosol samples, even though antibiotic use was markedly different between the two operations. Additionally, tet(W) genes were recovered in outdoor air within 2 km of livestock operations, which suggests that antibiotic resistance genes may be transported via aerosols on local scales. The integrase gene (intI1) from Class 1 integrons, which has been associated with multidrug resistance, was detected in CAFOs but not in human-occupied indoor environments, suggesting that CAFO aerosols could serve as a reservoir of multidrug resistance. In conclusion, our results show that CAFOs and clinics are sources of aerosolized antibiotic resistance genes that can potentially be transported via air movement.

Research paper thumbnail of GENOME ANALYSIS AND MARKERS

Cruciferae Newsletter, 2008

Canola (Brassica napus) is an economically important crop in Australia, supplying 13% of the worl... more Canola (Brassica napus) is an economically important crop in Australia, supplying 13% of the world demand for canola oil. Blackleg, caused by Leptosphaeria maculans is the most damaging disease affecting canola. In Australia highly virulent pathotypes predominate, leading to annual yield loss 10-15% with much greater losses, of up to 100%, observed during some years. We have developed gene expression microarray technology to examine changes in gene expression associated with blackleg infection in canola. Over 20,000 ...

Research paper thumbnail of High-Resolution Microbial Community Succession of Microbially Induced Concrete Corrosion in Working Sanitary Manholes

PLOS ONE, 2015

Microbially-induced concrete corrosion in headspaces threatens wastewater infrastructure worldwid... more Microbially-induced concrete corrosion in headspaces threatens wastewater infrastructure worldwide. Models for predicting corrosion rates in sewer pipe networks rely largely on information from culture-based investigations. In this study, the succession of microbes associated with corroding concrete was characterized over a one-year monitoring campaign using rRNA sequence-based phylogenetic methods. New concrete specimens were exposed in two highly corrosive manholes (high concentrations of hydrogen sulfide and carbon dioxide gas) on the Colorado Front Range for up to a year. Community succession on corroding surfaces was assessed using Illumina MiSeq sequencing of 16S bacterial rRNA amplicons and Sanger sequencing of 16S universal rRNA clones. Microbial communities associated with corrosion fronts presented distinct succession patterns which converged to markedly low α-diversity levels (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 10 taxa) in conjunction with decreasing pH. The microbial community succession pattern observed in this study agreed with culture-based models that implicate acidophilic sulfur-oxidizer Acidithiobacillus spp. in advanced communities, with two notable exceptions. Early communities exposed to alkaline surface pH presented relatively high α-diversity, including heterotrophic, nitrogen-fixing, and sulfur-oxidizing genera, and one community exposed to neutral surface pH presented a diverse transition community comprised of less than 20% sulfur-oxidizers.