High-biomass sorghums for biomass biofuel production

High-biomass sorghums are being developed as a dedicated energy crop for biofuels. Their high biomass yields provide large quantities of structural carbohydrates (cellulose, lignin, etc.) for energy production. Sorghum improvement for applications such as grain or fodder production is well established, but development of high-biomass sorghums for biofuels is not. Thus the objectives of this research were to develop information on sorghum improvement methods and criteria for high-biomass sorghums including marker-assisted selection, use of exotic germplasm, heterosis, and GxE variability of biomass composition. Marker-assisted selection was compared to testcross selection for identifying photoperiod-insensitive (PI) experimental lines that yield photoperiod-sensitive (PS) hybrids within the Ma1/Ma5/Ma6 hybrid production system. High-biomass sorghums are PS and the Ma1/Ma5/Ma6 hybrid production system produces PS hybrids with PI parents by manipulating alleles at the Ma1, Ma5 and Ma6 sorghum maturity loci. Four hundred eighty three sorghum lines were genotyped at the Ma1 and Ma5 loci to predict their hybrid photoperiod reactions and testcrossed to establish their actual hybrid photoperiod reactions. Ma1/Ma5 marker selections for lines producing PI hybrids were reliable and could be used to discard such lines. Ma1/Ma5 marker selections for lines producing PS hybrids were not reliable and identification of such lines will require testcrossing or potentially, genotyping at Ma6 or other additional loci. An attempt was made to determine whether meaningful relationships exist between the passport data (geographic origin) of exotic sorghum accessions and high-biomass desirability. Such a relationship could be used to prioritize exotic sorghum accessions for breeding evaluations. Seventeen hundred ninety two exotic sorghum accessions from 7 different geographic origins were evaluated for high-biomass desirability in 3 environments. Significant relationships between passport data and high-biomass desirability were identified within environments but were not applicable across environments because of large GxE interactions. A larger sampling of environments will be needed to understand and establish reliable passport data and high-biomass desirability GxE patterns. High-parent heterosis can improve yields in high-biomass sorghums and hybrid entries derived from high-biomass sorghum pollinators and grain sorghum females were evaluated for biomass heterosis. Grain sorghum females enable commercial seed production of high-biomass sorghums. Moderate levels of biomass high-parent heterosis were widely available in the hybrids. Heterosis and biomass yields were maximized in specific hybrid combinations and were subject to GxE interactions. Biomass composition (percent cellulose, hemicellulose, etc.) affects the conversion efficiency of biomass to liquid fuels and may be altered via breeding selections. Breeding methods and genotype recommendations for biomass composition will require consideration of GxE variability. The biomass composition of 12 sorghums grown across 5 environments was estimated using Near-Infrared Spectroscopy to identify GxE patterns. Significant GxE interactions for biomass composition were identified, but most compositional variability was attributable to environmental differences. Differences between genotypes for compositional traits were small (1-3 percent), but may prove important with large-scale biomass processing

Hybrid Quantum and Classical Mechanical Monte Carlo Simulations of the Interaction of Hydrogen Chloride with Solid Water Clusters

Monte Carlo simulations using a hybrid quantum and classical mechanical potential were performed for crystal and amorphous-like HCl-water(n) clusters The subsystem composed by HCl and one water molecule was treated within Density Functional Theory, and a classical force field was used for the rest of the system. Simulations performed at 200 K suggest that the energetic feasibility of HCl dissociation strongly depends on its initial placement within the cluster. An important degree of ionization occurs only if HCl is incorporated into the surface. We observe that local melting does not play a crucial role in the ionization process.Comment: 14 Latex pages with 4 postscript figures, to appear in Chem. Phys. Let

Challenging homophobic bullying in schools: the politics of progress

In recent years homophobic bullying has received increased attention from NGOs, academics and government sources and concern about the issue crosses traditional moral and political divisions. This article examines this ‘progressive’ development and identifies the ‘conditions of possibility’ that have enabled the issue to become a harm that can be spoken of. In doing so it questions whether the readiness to speak about the issue represents the opposite to prohibitions on speech (such as the notorious Section 28) or whether it is based on more subtle forms of governance. It argues that homophobic bullying is heard through three key discourses (‘child abuse’, ‘the child victim’ and ‘the tragic gay’) and that, while enabling an acknowledgement of certain harms, they simultaneously silence other needs and experiences. It then moves to explore the aspirational and ‘liberatory’ political investments that underlie these seemingly ‘common-sense’ descriptive discourses and concludes with a critique of the quasi-criminal responses that the dominant political agenda of homophobic bullying gives rise to. The article draws on, and endeavours to develop a conversation between, critical engagements with the contemporary politics of both childhood and sexuality

Max filtering with reflection groups

Given a finite-dimensional real inner product space V and a finite subgroup G of linear isometries, max filtering affords a bilipschitz Euclidean embedding of the orbit space V/G. We identify the max filtering maps of minimum distortion in the setting where G is a reflection group. Our analysis involves an interplay between Coxeter's classification and semidefinite programming

Wolbachia and DNA barcoding insects: patterns, potential and problems

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region

Comparing the performace of f1 testers versus their inbred line parents in evaluating experimental sorghum b and r lines in testcrosses.

An appropriate tester correctly identifies the relative performance of experimental lines while maximizing the differences between lines. Most sorghum breeding programs use elite inbred lines testers. Inbred line testers evaluate experimental lines against a specific genetic background, possibly increasing the probability of incorrectly discarding material. A potential solution would be to use F1 testers that combine two genetic backgrounds. The purpose of this research was to compare F1 testers versus inbred line testers for evaluating experimental sorghum lines in testcrosses Line x tester analyses were performed to assess tester consistency in assigning ranks. With one exception, all of the line x tester analyses were non-significant, indicating that the testers provided similar evaluations of the experimental lines. Correlations between the ranking of the experimental lines by their average performance and the rank assignments of each tester were measured to further asses tester accuracy. In all cases, the rank correlations were highly significant, implying that all of the testers accurately ranked experimental lines. In addition, all of the testers consistently identified the majority of the top performing experimental lines despite some important rank shifts. F-ratios for variance among the experimental lines (entry effect) were compared with the Schumann-Bradley statistical test to compare efficiencies. With one exception, the F1 testers always produced the largest or second largest entry effect F-ratio. Where the F1 testers produced the second largest F-ratio, it was not declared statistically different from the largest F-ratio by the Schumann-Bradley test, indicating that the testers had similar discriminatory efficiencies. Testcross variances were measured to further compare discriminatory efficiencies. With one exception, the F1 testers consistently produced the largest variances, evidence that the F1 testers were effective in maximizing differences among the experimental lines. The results indicate that F1 testers represent valid testers for evaluating experimental sorghum lines against two genetic backgrounds in a single testcross

Buried Bedrock Topography of the Cannon River System Around Northfield, Minnesota

A geophysical survey in the area of Northfield, Minnesota, involving electrical earth resistivity profiling and seismic refraction soundings, showed sizeable buried river channels in the bedrock in the Cannon River Valley which greatly increase in size downstream of Northfield. The channels upstream from the Northfield appear to be continuous and connect with the large buried channel between Northfield and Cannon Falls. The major buried valley deviates from the modern course of the Cannon River within the City of Northfield, but appears to follow elsewhere

Predatory senescence in ageing wolves

It is well established that ageing handicaps the ability of prey to escape predators, yet surprisingly little is known about how ageing affects the ability of predators to catch prey. Research into long-lived predators has assumed that adults have uniform impacts on prey regardless of age. Here we use longitudinal data from repeated observations of individually-known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to demonstrate that adult predatory performance declines with age and that an increasing ratio of senescent individuals in the wolf population depresses the rate of prey offtake. Because this ratio fluctuates independently of population size, predatory senescence may cause wolf populations of equal size but different age structure to have different impacts on prey populations. These findings suggest that predatory senescence is an important, though overlooked, factor affecting predator-prey dynamics. Supplemental table S! (15 pp.) attached below

Genome-wide binding of the CRISPR endonuclease Cas9 in mammalian cells

Bacterial type II CRISPR-Cas9 systems have been widely adapted for RNA-guided genome editing and transcription regulation in eukaryotic cells, yet their in vivo target specificity is poorly understood. Here we mapped genome-wide binding sites of a catalytically inactive Cas9 (dCas9) from Streptococcus pyogenes loaded with single guide RNAs (sgRNAs) in mouse embryonic stem cells (mESCs). Each of the four sgRNAs we tested targets dCas9 to between tens and thousands of genomic sites, frequently characterized by a 5-nucleotide seed region in the sgRNA and an NGG protospacer adjacent motif (PAM). Chromatin inaccessibility decreases dCas9 binding to other sites with matching seed sequences; thus 70% of off-target sites are associated with genes. Targeted sequencing of 295 dCas9 binding sites in mESCs transfected with catalytically active Cas9 identified only one site mutated above background levels. We propose a two-state model for Cas9 binding and cleavage, in which a seed match triggers binding but extensive pairing with target DNA is required for cleavage.National Institutes of Health (U.S.) (Grant RO1-GM34277)National Institutes of Health (U.S.) (Grant R01-CA133404)National Cancer Institute (U.S.) (Grant PO1-CA42063)National Cancer Institute (U.S.) (Cancer Center Support (Core) Grant P30-CA14051)National Institutes of Health (U.S.) (Director's Pioneer Award 1DP1-MH100706)Damon Runyon Cancer Research FoundationKinship Foundation. Searle Scholars ProgramSimons Foundatio

Evaluation of process for sludge particle size reduction

This document evaluates the available technology for K Basin sludge particle size. The results can be used to demonstrate the sensitivity or lack thereof, of K Basin sludge to available reduction processes and TWRS proposed particle acceptance criteria