Life Sciences | Open Access Articles | Digital Commons Network™

Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks

Dartmouth Scholarship

Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. …

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Deriving Fuel Mass By Size Class In Douglas-Fir (Pseudotsuga Menziesii) Using Terrestrial Laser Scanning, Carl Seielstad, Crystal Stonesifer, Eric Rowell, Lloyd Queen

Forest Management Faculty Publications

Requirements for describing coniferous forests are changing in response to wildfire concerns, bio-energy needs, and climate change interests. At the same time, technology advancements are transforming how forest properties can be measured. Terrestrial Laser Scanning (TLS) is yielding promising results for measuring tree biomass parameters that, historically, have required costly destructive sampling and resulted in small sample sizes. Here we investigate whether TLS intensity data can be used to distinguish foliage and small branches (less than or equal to 0.635 cm diameter; coincident with the one-hour timelag fuel size class) from larger branchwood (>0.635 cm) in Douglas-fir (Pseudotsuga …

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Effects Of Species, Water, And Nitrogen On Competition Among Three Prairie Grasses, Jerry L. Weatherford, Randall W. Myster

The Prairie Naturalist

We conducted an experiment to investigate effects of species, water (W), and nitrogen (N) on competition among little bluestem (Schizachyrium scoparium), sideoats grama (Bouteloua curtipendula), and indiangrass (Sorghastrum nutans). All biomass parameters and the root:shoot ratio of little bluestem were reduced by the presence off 1 of 2 other species, and its shoot biomass and total biomass were both increased by addition of N. Root and shoot biomass of sideoats grama were reduced by the presence of indiangrass and its total biomass was reduced by the presence of itself, whereas its shoot biomass was increased by addition of W at …

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Global Human Footprint On The Linkage Between Biodiversity And Ecosystem Functioning In Reef Fishes, Camilo Mora, Octavio Aburto-Oropeza, Arturo Ayala Bocos, Paula M. Ayotte, Stuart Banks, Andrew G. Bauman, Maria Beger, Sandra Bessudo, David J. Booth, Eran Brokovich, Andrew Brooks, Pascale Chabanet, Josh Eli Cinner, Jorge Cortes, Juan J. Cruz-Motta, Amilcar Cupul Magaña, Edward E. Demartini, Graham J. Edgar, David A. Feary, Sebastian C. A. Ferse, Alan M. Friedlander, Kevin J. Gaston, Charlotte Gough, Nicholas A. J. Graham, Alison Green, Hector M. Guzman, Marah Hardt, Michel Kulbicki, Yves Letourneur, Andres López Pérez, Michel Loreau, Yossi Loya, Camilo Martinez, Ismael Mascareñas-Osorio, Tau Morove, Marc-Olivier Nadon, Yohei Nakamura, Gustavo Paredes, Nicholas V.C. Polunin, Morgan S. Pratchett, Hector Reyes Bonilla, Fernando Rivera, Enric Sala, Stuart A. Sandin, German Soler, Rick Stuart-Smith, Emmanuel Tessier, Derek P. Tittensor, Mark Tupper, Paolo Usseglio, Laurent Vigliola, Laurent Wantiez, Ivor D. Williams, Shaun K. Wilson, Fernando A. Zapata

Marine & Environmental Sciences Faculty Articles

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more …

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Performance Screening Of Chemostat Adapted Recombinant Zymomonas Mobilis Strains, Deirdre M. Beard, Nancy Dowe

STAR Program Research Presentations

Corn stover biomass can be pretreaed and hydrolyzed into soluble sugars to be fermented by microorganisms to ethanol. NREL has developed a recombinant bacteria Zymomonas mobilis 8b that metabolizes both five and six carbon sugars. During pretreatment, toxic inhibitors such as furfural and acetate are produced. NREL has made an attempt to adapt two sub-strains of Z. mobilis 8b to acetate and furfural by using a chemostat method. During the chemostat process, cultures were frozen back in glycerol and saved. In this study, those frozen cultures were revived and analyzed for performance in environments with varying concentrations of furfural and …

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Nitrogen Fixation And Seeding Rates Of Common Vs. Hairy Vetch For Interseeding Into Established Switchgrass Stands, K. Warwick, F. L. Allen, Patrick D. Keyser, G. E. Bates, D. D. Tyler, P. L. Lambdin, A. J. Ashworth

Research Reports

Interest in alternatives to synthetic nitrogen (N) fertilizer sources for switchgrass (Panicum virgatum L.) production, such as interseeding with N- fixing legumes continues to increase. Common vetch (Vicia sativa) is a N-fixing legume that occurs naturally throughout the U.S. and has less hard seed than hairy vetch (Vicia villosa), making it potentially less invasive, and it may fix N at similar rates to that of hairy vetch. However, little data exist to substantiate this. In this study, N-fixation rates via the N-difference method were determined to be 59.3 and 43.3 kg N ha-1 …

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Forest Structure And Aboveground Biomass In The Southwestern United States From Modis And Misr, Mark Chopping, Crystal B. Schaaf, Feng Zhao, Zhuosen Wang, Anne Nolin, Gretchen G. Moisen, John V. Martonchik, Michael Bull

USDA Forest Service / UNL Faculty Publications

Red band bidirectional reflectance factor data from the NASA MODerate resolution Imaging Spectroradiometer (MODIS) acquired over the southwestern United States were interpreted through a simple geometric–optical (GO) canopy reflectance model to provide maps of fractional crown cover (dimensionless), mean canopy height (m), and aboveground woody biomass (Mg ha⁻¹) on a 250 m grid. Model adjustment was performed after dynamic injection of a background contribution predicted via the kernel weights of a bidirectional reflectance distribution function (BRDF) model. Accuracy was assessed with respect to similar maps obtained with data from the NASA Multiangle Imaging Spectroradiometer (MISR) and to contemporaneous …

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Stem-Boring Caterpillars Of Switchgrass In The Midwestern United States, Jarrad R. Prasifka, Jennifer E. Buhay, Thomas W. Sappington, Emily A. Heaton, Jeffrey Bradshaw, Michael E. Gray

Panhandle Research and Extension Center

Lepidopteran stem borers were collected from switchgrass, Panicum virgatum L., tillers showing symptoms of infestation at seven locations in Illinois and Iowa, with additional observations made on larval and adult activity. Blastobasis repartella (Dietz) (Coleophoridae), whose only known host is switchgrass, was common in plots grown for >5 yr, whereas the polyphagous stalk borer, Papaipema nebris (Guenée) (Noctuidae), was abundant in newly established (i.e., first- and second year) switchgrass. Haimbachia albescens Capps (Crambidae) was collected from two locations in Illinois, making switchgrass the first known host for this species. Entry holes made by B. repartella and H. albescens were usually …

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Effects Of Aging On Organic Aerosol From Open Biomass Burning Smoke In Aircraft And Laboratory Studies, M J. Cubison, A M. Ortega, P L. Hayes, D K. Farmer, D Day, M J. Lechner, W H. Brune, E Apel, G S. Diskin, J A. Fisher, H E. Fuelberg, A Hecobian, D J. Knapp, T Mikoviny, D Riemer, G W. Sachse, W Sessions, R Weber, A J. Weinheimer, A Wisthaler, J L. Jimenez

Faculty of Science - Papers (Archive)

Biomass burning (BB) is a large source of primary and secondary organic aerosols (POA and SOA). This study addresses the physical and chemical evolution of BB organic aerosols. Firstly, the evolution and lifetime of BB POA and SOA signatures observed with the Aerodyne Aerosol Mass Spectrometer are investigated, focusing on measurements at high-latitudes acquired during the 2008 NASA ARCTAS mission, in comparison to data from other field studies and from laboratory aging experiments. The parameter f60 , the ratio of the integrated signal at m/z 60 to the total signal in the organic component mass spectrum, is used as a …

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Full-Text Articles in Life Sciences

Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks

Dartmouth Scholarship

Deriving Fuel Mass By Size Class In Douglas-Fir (Pseudotsuga Menziesii) Using Terrestrial Laser Scanning, Carl Seielstad, Crystal Stonesifer, Eric Rowell, Lloyd Queen

Forest Management Faculty Publications

Effects Of Species, Water, And Nitrogen On Competition Among Three Prairie Grasses, Jerry L. Weatherford, Randall W. Myster

The Prairie Naturalist

Marine & Environmental Sciences Faculty Articles

Performance Screening Of Chemostat Adapted Recombinant Zymomonas Mobilis Strains, Deirdre M. Beard, Nancy Dowe

STAR Program Research Presentations

Nitrogen Fixation And Seeding Rates Of Common Vs. Hairy Vetch For Interseeding Into Established Switchgrass Stands, K. Warwick, F. L. Allen, Patrick D. Keyser, G. E. Bates, D. D. Tyler, P. L. Lambdin, A. J. Ashworth

Research Reports

Forest Structure And Aboveground Biomass In The Southwestern United States From Modis And Misr, Mark Chopping, Crystal B. Schaaf, Feng Zhao, Zhuosen Wang, Anne Nolin, Gretchen G. Moisen, John V. Martonchik, Michael Bull

USDA Forest Service / UNL Faculty Publications

Stem-Boring Caterpillars Of Switchgrass In The Midwestern United States, Jarrad R. Prasifka, Jennifer E. Buhay, Thomas W. Sappington, Emily A. Heaton, Jeffrey Bradshaw, Michael E. Gray

Panhandle Research and Extension Center

Faculty of Science - Papers (Archive)