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Full-Text Articles in Organisms

The Discovery Of Metarhizium Anisopliae (Metchnikoff) Sorokin Isolates From Arkansas And Their Pathogenicity To Amblyomma Americanum L., Austin Goldsmith May 2020

The Discovery Of Metarhizium Anisopliae (Metchnikoff) Sorokin Isolates From Arkansas And Their Pathogenicity To Amblyomma Americanum L., Austin Goldsmith

Graduate Theses and Dissertations

The lone star tick Amblyomma americanum L. is the most abundant tick in Arkansas and has been implicated as a vector of many important disease-causing pathogens. Many species of entomopathogenic fungi have been isolated from several species of ticks, with some of these fungi being utilized for tick biocontrol. However, few studies have assessed the pathogenicity of entomopathogenic fungi to A. americanum. The objectives of this study were to: isolate and identify native Arkansas isolates of entomopathogenic fungi from wild A. americanum ticks exposed to soil and to compare the pathogenicity of one isolate (Metarhizium anisopliae (Metchnikoff) Sorokin isolate Savoy …


Selectivity Of Infrared Heat Treatment On Inactivation Of Mycotoxigenic Fungi On Stored Grain, Shantae A. Wilson Aug 2019

Selectivity Of Infrared Heat Treatment On Inactivation Of Mycotoxigenic Fungi On Stored Grain, Shantae A. Wilson

Graduate Theses and Dissertations

Selective Infrared (IR) heating holds great potential to decontaminate spores of unsafe fungi in corn. The objectives for this study were to investigate the impact of exposing corn to infrared energy at selected peak wavelengths (λ), infrared intensities and treatment durations, followed by tempering for further inactivation of microbes on the grain and explore a method for decontaminating Aspergillus flavus (A. flavus) spores on corn. Freshly harvested corn with initial moisture contents (IMCs) of 16%, 20%, and 24% wet basis (w.b.) were used. The corn samples were treated at different infrared wavelengths (3.2, 4.5, and 5.8 μm) for 20, 40 …


The Effect Of Prescribed Burning On Wood-Decay Fungi In The Forests Of Northwest Arkansas, Nawaf Ibrahim Alshammari Aug 2019

The Effect Of Prescribed Burning On Wood-Decay Fungi In The Forests Of Northwest Arkansas, Nawaf Ibrahim Alshammari

Graduate Theses and Dissertations

Prescribed burning is defined as the process of the planned application of fire to a predetermined area under specific environmental conditions in order to achieve a desired outcome such as land management. This project used both morphological and molecular methods to identify and characterize the wood-decay fungi associated with the forests of northwest Arkansas—Pea Ridge National Military Park, Devil’s Den State Park, and the Buffalo National River—through frequent visits made between February 2018 and February 2019. In addition, in order to assess the effects of prescribed burning, incubation chambers were used to compare the growth of fungi from both unburned …


Effect Of Macrograzers (Campostoma Spp. And Faxonius Spp.) On Periphyton In Ozark Streams With Considerations Given To Macrograzer Biomass, Phosphorus, And Season: Mensurative And Manipulative Studies, Kayla R. Sayre Dec 2018

Effect Of Macrograzers (Campostoma Spp. And Faxonius Spp.) On Periphyton In Ozark Streams With Considerations Given To Macrograzer Biomass, Phosphorus, And Season: Mensurative And Manipulative Studies, Kayla R. Sayre

Graduate Theses and Dissertations

Nutrient and benthic algal biomass relationships can guide numeric nutrient criteria development in lotic systems. However, herbivorous macrograzers may confound this relationship by reducing the slope of the positive relationship between nutrients and periphyton biomass in streams. I conducted a mensurative field study to determine if stoneroller and crayfish abundance related to algal biomass at varying nutrient concentrations and manipulated macrograzer presence with electrical exclosures in streams to examine macrograzer effects on algal biomass and understand whether these effects on periphyton varied with total phosphorus (TP) or season. Macrograzer density was quantified across a TP gradient (n=15 streams; range = …


Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen Dec 2017

Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen

Graduate Theses and Dissertations

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, …


The Production Of Biobutanol From Biomass Via A Hybrid Biological/Chemical Process, Thomas Melvin Potts May 2015

The Production Of Biobutanol From Biomass Via A Hybrid Biological/Chemical Process, Thomas Melvin Potts

Graduate Theses and Dissertations

Biobutanol use as a fuel began in the late 19th century. Problems remain in economic viability. A review of the state of the art and need for technical advances is presented.

The technical potential of producing biofuel from a naturally occurring macroalgae was studied. The algae grow in Jamaica Bay, New York City, in contaminated water. The process consisted of mechanical harvesting, drying, grinding, and acid hydrolysis to form an algal sugar solution. Clostridium beijerinckii and C. saccharoperbutylacetonicum were used in an acetone butanol ethanol (ABE) fermentation to make butanol. Fermentation was followed by distillation Butanol concentrations during fermentation reached …


Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour Dec 2014

Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour

Graduate Theses and Dissertations

Filamentous fungi are responsible for numerous plant and animal diseases. The filamentous ascomycete Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. Also of substantial concern is the contamination of infected kernels with fumonisins, toxic secondary metabolites linked to toxicoses in humans and livestock. The number of sequenced fungal genomes is rapidly increasing. However, functional characterization of fungal genes has not progressed at a comparable rate. In pathogenic fungi, uncharacterized genes represent a source for novel virulence factors or anti-fungal targets. Therefore, to fully understand the genetic mechanisms underlying fungal pathogenesis, …


Development Of Novel Antifungal Peptides Based On A Natural Model Of Histatin-5 Peptide, Duy Tu Nguyen Dec 2013

Development Of Novel Antifungal Peptides Based On A Natural Model Of Histatin-5 Peptide, Duy Tu Nguyen

Graduate Theses and Dissertations

Our research group is working toward the development of novel antifungal peptides based on a natural model of peptide histatin-5. Histatin-5 is found in human saliva and known to protect our body against oral infections by Candida species. Candidiasis, or an infection caused by Candida species, is considered one of the most medically important fungal infections worldwide. Blood stream infections caused by Candida species are the fourth leading cause of hospital-acquired fungal infections that is associated with high mortality rates and high costs of treatment. This study investigated the modes of action of histatin-5 with the use of one 16-mer …


Relationships Between Landscape Factors And Crayfish Density And The Interacting Effects Of Grazing And Increased Sedimentation On Algal Biomass, Katheryn Haley Rose Dec 2013

Relationships Between Landscape Factors And Crayfish Density And The Interacting Effects Of Grazing And Increased Sedimentation On Algal Biomass, Katheryn Haley Rose

Graduate Theses and Dissertations

In recent years in the United States there has been a rapid expansion in anthropogenic sources of sediment in streams including construction, agriculture, and drilling for natural gas. Potential effects land disturbance associated with activities from natural gas development on aquatic biota in surrounding streams have not yet been well documented. An increase in inorganic sediment in streams can be detrimental to organisms through a variety of mechanisms including alteration of dominant substrate type, higher turbidity resulting in lower visibility, and burial of food resources such as algae and detritus. Increasing sedimentation in stream environments through anthropogenic disturbance is a …


Role Of Lactic Acid Bacteria As A Bio-Sanitizer To Prevent Attachment Of Listeria Monocytogenes On Deli Slicer Contact Surfaces, And The Influence Of Listeria Innocua On The Attachment Of L. Monocytogenes On Selected Materials Located In The Food-Processing Environment, Jean Baptiste Ndahetuye May 2012

Role Of Lactic Acid Bacteria As A Bio-Sanitizer To Prevent Attachment Of Listeria Monocytogenes On Deli Slicer Contact Surfaces, And The Influence Of Listeria Innocua On The Attachment Of L. Monocytogenes On Selected Materials Located In The Food-Processing Environment, Jean Baptiste Ndahetuye

Graduate Theses and Dissertations

Listeria monocytogenes an important foodborne pathogen that continues to be a serious problem for the food industry. This pathogen contaminates food primarily during post-harvest in the food-processing environment. Its ecology in the food-processing environment is not well understood but previous research has demonstrated the ability of L. monocytogenes to survive on food contact surfaces after cleaning and disinfection. The current study explored the attachment of three lactic acid bacteria (LAB) strains, Lactobacillus animalis , Lb. amylovorus and Pediococcus acidilactici , their combination in a cocktail, and their influence to prevent the attachment of L. monocytogenes at room temperature by examining …


Recombinant Protein Production In Bacillus Species, Isolation And Methionine Production In Methionine-Producing Microorganisms, Suwat Saengkerdsub May 2012

Recombinant Protein Production In Bacillus Species, Isolation And Methionine Production In Methionine-Producing Microorganisms, Suwat Saengkerdsub

Graduate Theses and Dissertations

Linoleic acid isomerase (LAI) is the enzyme that converts linoleic acid to conjugated linoleic acids (CLAs) which appear to be capable of lowering cancer risk and enhancing immunity. There is an interest in developing commercial processes for the production of single isomers of CLA by biotransformation of LA using microbial cells and enzymes. However, the evaluation of these strains suggest that growth and LA isomerase production levels by these anaerobes are insufficient to support economic commercial production of single CLA isomers. A better alternative is to clone the isomerase gene and to generate new production strains using recombinant technology. Bifidobacterium …