Biology Commons^™

Analysis Of Plant Lignin Formation And Engineering For Biofuels Production, Deborah Lynn Petrik

Theses and Dissertations

ANALYSIS OF PLANT LIGNIN FORMATION AND ENGINEERING FOR BIOFUELS PRODUCTION

Deborah L. Petrik

149 Pages August 2015

Grasses such as switchgrass and Miscanthus are attractive feedstock candidates for second generation biofuels because they are perennials that can grow on less fertile or "marginal" lands not used for food crops, require little fertilizer and modest pest and disease management, and are not a human food source. Releasing the energy potential contained in plant-based cellulosic material requires either conversion to a liquid biofuel such as ethanol or burning. Thus, much of the current research focuses on not only understanding grass development as …

Factors Constraining The Reproductive Output Of Baptisia Alba Macrophylla, Ashley Morgan Hembrough

Theses and Dissertations

Baptisia alba macrophylla, a native, herbaceous perennial legume, produces inflorescences with a large number of flowers, yet matures relatively few fruits. We hypothesized that the number of seeds matured by B. alba macrophylla is maximized based on resource availability at each stage of development, but this optimal number is further compromised by extrinsic factors including pollen limitation and pre-dispersal seed predation by the weevils Apion rostrum and Tychius sordidus. To test this hypothesis, we conducted a field experiment at two sites: (i) the John English Prairie, located in Hudson, IL, and also (ii) the Sugar Grove Nature Center and Funks …

Switching Tactics: Phenotypic Plasticity In The Alternative Mate-Finding Tactics Of Burying Beetles, Theresa Mulrey

Theses and Dissertations

Male Nicrophorus burying beetles utilize two alternative mate-finding tactics, representing an ideal model system to test the influence of environmental cues on the expression of alternative tactics. The "searching" tactic involves flying in search of a carcass on which to mate. This tactic can result in high levels of paternity, but is risky in that carcasses are rare and competition for carcasses is fierce. The "signaling" tactic, which involves emitting pheromone in the absence of a carcass to attract females, is energetically less costly, but a signalling male must mate with multiple females to achieve the same reproductive returns as …

Investigations Into The Genomes Of Two Ascomyetes, Jay Wilbur Pyle

Theses and Dissertations

Fusarium verticillioides is a filamentous ascomycete that is both a plant endophyte and pathogen, causing disease during any life stage of the plant. When F. verticillioides grows in maize the fungus can synthesis a number of mycotoxins including the fumonisins, which have been linked with human esophageal cancer and neural tube associated birth defects. In an attempt to control fumonisin production our lab is searching the genome of F. verticillioides for a selfish genetic element known as Spore killer. The plan is simple; we envision creating a bio-control strain capable of harnessing the genetic transmission-distorting properties of Spore killer to …

Investigating The Initial Detection Stage Of Meiotic Silencing By Unpaired Dna In The Model Organism Neurospora Crassa, Pegan A. Sauls

Theses and Dissertations

In an attempt to neutralize transposable elements or retrovirus invasions Neurospora crassa will rely on one of its many genome defense mechanism, Meiotic Silencing by Unpaired DNA (MSUD). MSUD works in a two-step process that first detects unpaired sequences between homologous chromosomes followed by downstream silenced expression of the sequence. The ultimate silencing stage of MSUD is widely accepted to operate through an RNAi-like system. However, the mechanics of the detection step of MSUD remains elusive. The research presented attempts to elaborate on how the initial stage of MSUD occurs and its specifics. First, a genetic approach is utilized to …

Hatching Asynchrony In European Starlings ( Sturnus Vulgaris ), Jason Hanser

Theses and Dissertations

Across a wide range of avian taxa, eggs within clutches hatch asynchronously, placing later hatched nestlings at a disadvantage. Here, we explore the proximate and ultimate causes of hatching asynchrony within European starlings, Sturnus vulgaris. Specifically, we investigate the effect of ambient temperature on egg viability and incubation behavior prior to clutch completion. Additionally, we examine the potential for storage time and maternally-deposited yolk testosterone to influence rates of embryonic development and hatching patterns within European starlings.

Seta Structure In Members Of The Coleochaetales ( Streptophyta ), Timothy Richard Rockwell

Theses and Dissertations

The charophycean green algae, which include the Coleochaetales, together with land plants form a monophyletic group, the streptophytes. The order Coleochaetales, a possible sister taxon to land plants, is defined by its distinguishing setae (hairs), which are encompassed by a collar. Previous studies of these setae yielded conflicting results and were confined to one species, Coleochaet. scutata. In order to interpret these results and learn about the evolution of this character, setae of four species of Coleochaete and the genus Chaetosphaeridium within the Coleochaetales were studied to determine whether cellulose, callose, and phenolic compounds contribute to the chemical composition of …

Environmental Impacts On Life History In Container Breeding Mosquitoes, Kathleen May Westby

Theses and Dissertations

In this dissertation I explore different ways that the environment impacts life history in mosquitoes in ways that may alter vectorial capacity. In chapter I, I tested if short-term sugar deprivation experienced after exposure to La Crosse virus altered infection rates in Aedes albopictus and if sugar treatment and virus infection status altered blood feeding behavior and fecundity. I found no evidence that sugar deprivation impacted infection rates or fecundity. Sugar deprivation did increase blood feeding. There was no effect of infection status on blood feeding or fecundity. In chapter II, I tested for effects of seasonal cues (temperature and …

In Vivo Modulation Of Rhythmically Active Neural Networks In The Crustacean Stomatogastric Ganglion, Alexandra Mead Yarger

Theses and Dissertations

Rhythmic motor patterns are found throughout all living organisms and are responsible for maintaining some of our most fundamental behaviors. The motor circuits producing these behaviors are flexible and able to adapt to changing internal and environmental conditions, yet stable enough to maintain function within certain boundaries. Central pattern generators (CPGs), which are the primary source of this stability, reliably maintain activity patterns and thus the behaviors they drive. The crab stomatogastric nervous system contains the well-characterized gastric mill (chewing) and pyloric (filtering of food) CPGs. In vitro, the pyloric rhythm is stereotyped with little variation over time. Temperature, inter-circuit …

Using Deuterium And Garp To Estimate Geographic Extents Of Source Populations Of Hoary ( Lasiurus Cinereus ) And Eastern Red ( Lasiurus Borealis ) Bats Killed At A Central Illinois Wind Facility, Rachael Anne Van Essen

Theses and Dissertations

High bat mortality at wind energy facilities is a widely cited conservation issue, but the population-level impacts are not understood. In Illinois, the main species affected are migratory tree bats like the Hoary (Lasiurus cinereus) and Eastern Red (Lasiurus borealis).This research used deuterium isotope analysis of hair combined with ecological niche modeling (GARP: Genetic Algorithm for Rule-set Prediction) in a novel way to map the geographic extents of Hoary and Eastern Red bat specimens salvaged at a single central Illinois wind facility from 2008-2010. Hair was chosen after determining that the claw is currently a problematic tissue due to a …

The Effects Of Invasive Macrophytes Phragmites Australis And Typha Angustifolia On Nitrate Removal In High Nitrate Wetland Sediments, Lauren Mackenzie Beal

Theses and Dissertations

Constructed wetlands are quickly becoming inundated with invasive species like Phragmites australis and Typha angustifolia which are capable of changing whole ecosystem function and community composition. We wanted to assess how plants affect dissolved oxygen (DO) and dissolved organic carbon concentrations (DOC), and in turn if they increase nitrate (NO3-N) removal rates relative to barren sediments. Using a NO3-N/Br tracer test, we tested NO3-N removal rates, DO, and DOC concentrations. After the tracer test, we measured above- and below-ground plant biomass and sediment characteristics. NO3-N removal did not differ across the treatments. Phragmites australis microcosms had significantly higher sediment bulk …

Identification Of Transcriptionally Quiescent Regions In The Neurospora Crassa Genome, Katie Marie Groskreutz

Theses and Dissertations

Sexual reproduction and genetic exchange via meiosis are important and highly conserved processes in many living organisms. Occasionally, complications occur during meiosis that can result in chromosome abnormalities. In humans, improper chromosome development can cause life altering disorders such as Down Syndrome, Edwards Syndrome, and Patau Syndrome. Unfortunately, despite its importance, gaps remain in our knowledge of how this process works. For instance, little is known about how homolog identification occurs and what proteins identify matching chromosomes during pairing. This fundamental process occurs early during meiosis and ensures proper development of gametes.

Understanding the proteins involved during homolog pairing may …

An Investigation Into The Presynaptic Actions By Which Amphetamine Activates Dopamine Signaling Within Striatal Subregions Of The Rat., Dan P. Covey

Theses and Dissertations

Despite decades of intense research and a consensus view in the field, the work presented herein provides strong evidence that the primary mechanism of amphetamine action should be re-evaluated. Rather than depleting vesicular dopamine stores and promoting non-exocytotic efflux through the dopamine transporter in vivo, recent evidence demonstrates that amphetamine augments phasic dopamine signaling instead. This signaling modality is critical for reinforcement learning and is dependent on intact vesicular stores. The new findings support over-activation of phasic dopamine signaling as a common mechanism in the addiction process.