Generating Phenotypic Diversity in a Fungal Biocatalyst to Investigate Alcohol Stress Tolerance Encountered during Microbial Cellulosic Biofuel Production

peer-reviewedConsolidated bioprocessing (CBP) of lignocellulosic biomass offers an alternative route to renewable energy. The crop pathogen Fusarium oxysporum is a promising fungal biocatalyst because of its broad host range and innate ability to co-saccharify and ferment lignocellulose to bioethanol. A major challenge for cellulolytic CBP-enabling microbes is alcohol inhibition. This research tested the hypothesis that Agrobacterium tumefaciens - mediated transformation (ATMT) could be exploited as a tool to generate phenotypic diversity in F. oxysporum to investigate alcohol stress tolerance encountered during CBP. A random mutagenesis library of gene disruption transformants (n=1,563) was constructed and screened for alcohol tolerance in order to isolate alcohol sensitive or tolerant phenotypes. Following three rounds of screening, exposure of select transformants to 6% ethanol and 0.75% n-butanol resulted respectively in increased (≥11.74%) and decreased (≤43.01%) growth compared to the wild –type (WT). Principal component analysis (PCA) quantified the level of phenotypic diversity across the population of genetically transformed individuals and isolated candidate strains for analysis. Characterisation of one strain, Tr. 259, ascertained a reduced growth phenotype under alcohol stress relative to WT and indicated the disruption of a coding region homologous to a putative sugar transporter (FOXG_09625). Quantitative PCR (RT-PCR) showed FOXG_09625 was differentially expressed in Tr. 259 compared to WT during alcohol-induced stress (P<0.05). Phylogenetic analysis of putative sugar transporters suggests diverse functional roles in F. oxysporum and other filamentous fungi compared to yeast for which sugar transporters form part of a relatively conserved family. This study has confirmed the potential of ATMT coupled with a phenotypic screening program to select for genetic variation induced in response to alcohol stress. This research represents a first step in the investigation of alcohol tolerance in F. oxysporum and has resulted in the identification of several novel strains, which will be of benefit to future biofuel research.Funding provided through the Irish Department of Agriculture and Food's Research Stimulus Fund (Project Code RSF 07 513

Reactions to the Presistent Gender Disparity in Student Note Publication

Article published in the Michigan State Law Review

Silence as Insubordination: Friday and Michael K’s Wordless Weapon, A Post-Colonial Approach toJ.M. Coetzee’s Foe and Life and Times of Michael K

While most critics of J.M. Coetzee’s fiction focus on silence as a weapon of imperial oppressive forces to subjugate representations of the other, this thesis argues that, on the contrary, characters representing the traditional colonially oppressed use their silence as a weapon to in turn oppress the representations of imperial power. Through close reading explication and the use of the post-colonial theories of both Homi Bhabha and Edward Said, I focus on the inverted oppression, the shifting of identity, and the role of authorial authority within the novels, Foe and Life & Times of Michael K. By engaging in this close examination, I debunk early criticisms of Coetzee’s fiction that his work failed to take a formative stance on the politics of the Apartheid. My main focus is the way in which Coetzee chooses his diction to evoke powerful imagery and symbolism, correlating the conflicts, both internal and external, of his characters with the real ideological and physical conflicts that encompassed the Apartheid

Dendritic to globular morphology transition in ternary alloy solidification

The evolution of solidification microstructures in ternary metallic alloys is investigated by adaptive finite element simulations of a general multicomponent phase-field model. A morphological transition from dendritic to globular growth is found by varying the alloy composition at a fixed undercooling. The dependence of the growth velocity and of the impurity segregation in the solid phase on the composition is analyzed and indicates a smooth type of transition between the dendritic and globular growth structures.Comment: 4 pages, 2 figure

Immiscible fluid: Heat of fusion heat storage system

Both heat and mass transfer in direct contact aqueous crystallizing systems were studied as part of a program desig- ned to evaluate the feasibility of direct contact heat transfer in phase change storage using aqueous salt system. Major research areas, discussed include (1) crystal growth velocity study on selected salts; (2) selection of salt solutions; (3) selection of immiscible fluids; (4) studies of heat transfer and system geometry; and (5) system demonstration

Flowering in Vitis: Effects oi genotype on cytokinin-induced conversion oi tenddls into inflorescences

Tendrils of several Vitis species and hybrids were transformed into inflorescences by repeated treatment of shoot apices with 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA, 50-1000 flM). Tendrils of male vines were more readily converted into inflorescences by PBA-treatment than those of females or hermaphrodite vines. V. vinifera, V. rupestris and their hybrids were more responsive to PBA-treatment than V. monticola, V. girdiana and Muscadinia rotundifolia. Bunches of gmpes with viable seeds were produced by tendril-derived inflorescences of the V. vinifera cultivars Muscat of Alexandria (☿) and Katakourgan (♀) and of a V. vinifera X V. rupestris hybrid (♂).Die Blütenbildung bei der Rebe: Der Einfluß des Genotyps auf die Cytokinin-induzierteUmwandlung von Ranken in InfloreszenzenDie Ranken verschiedener Vitis-Arten und -Bastarde entwickelten sich zu Infloreszenzen, wenn die Triebspitzen wiederholt mit 6-(Benzylamino)-9-(2-tetrahydropyranyl)-9H-purin (PBA; 50-1000 pM) behandelt wurden. Die Ranken männlicher Reben ließen sich durch PBA-Behandlung leichter in Infloreszenzen umwandeln als diejenigen weiblicher oder zwittriger Reben. V. vinifera, V. rupestris und ihre Kreuzungen reagierten stärker auf die PBA-Behandlung als V. monticola, V. girdiana und Muscadinia rotundifolia. Trauben mit lebensfähigen Samen entstanden aus rankenbürtigen Infloreszenzen der V.-vinifera-Sorten Muskat von Alexandria,(☿) und Katakourgan (♀) sowie einer V.-vinifera- x V.-rupestris-Kreuzung (♂)

GEODYN programmer's guide, volume 2, part 2

A computer program for executive control routine for orbit integration of artificial satellites is presented. At the beginning of each arc, the program initiates required constants as well as the variational partials at epoch. If epoch needs to be reset to a previous time, the program negates the stepsize, and calls for integration backward to the desired time. After backward integration is completed, the program resets the stepsize to the proper positive quantity

Low temperature shape relaxation of 2-d islands by edge diffusion

We present a precise microscopic description of the limiting step for low temperature shape relaxation of two dimensional islands in which activated diffusion of particles along the boundary is the only mechanism of transport allowed. In particular, we are able to explain why the system is driven irreversibly towards equilibrium. Based on this description, we present a scheme for calculating the duration of the limiting step at each stage of the relaxation process. Finally, we calculate numerically the total relaxation time as predicted by our results and compare it with simulations of the relaxation process.Comment: 11 pages, 5 figures, to appear in Phys. Rev.