Gadusol is a UV-B-absorbent compound found in fish and other marine organisms where it is presumed to play a role as a sunscreen and antioxidant. In light of commercial potential as a replacement for problematic synthetic sunscreens, a process to produce recombinant gadusol in the yeast Saccharomcyces cerevisiae was investigated....
The yeast Saccharomyces cerevisiae, commonly used in winemaking, baking, and brewing, also serves as a host for the production of therapeutically valuable pharmaceuticals. Recently, the Bakalinsky laboratory constructed a recombinant yeast strain expressing two zebrafish (Danio rerio) genes in order to produce a UV-protective “sunscreen” compound called gadusol. An antioxidant...
Reductive sulfate assimilation, the biological process by which sulfur-containing amino acids and key derivatives are synthesized from sulfate, is broadly shared among bacteria, fungi, and plants. It is the major, if not sole source of methionine and cysteine for Saccharomyces cerevisiae during wine fermentation. Two obligate intermediates formed in the...
Lignocellulosic biomass represents a vast and renewable source of fermentable sugar for
production of biofuels. However, native lignocellulose—comprised of cellulose,
hemicellulose and lignin—is refractory to degradation because the crystalline cellulose is
not easily hydrolyzed by cellulases. Standard chemical treatments of lignocellulose to
reduce the crystallinity of cellulose prior to enzymatic...
The studies described in this thesis were motivated by ongoing efforts to develop lignocellulosic biomass as an efficient and practical source of renewable energy. Enormous problems complicate these efforts to reduce reliance on greenhouse gas-generating fossil fuels. Simply obtaining the fermentable sugars available in the cellulose and hemicellulose components of...
Global warming and on-going depletion of fossil fuels have stimulated research to develop renewable sources of energy. Current renewable energy use comprises only 10% of the energy consumed in the US and is focused mostly on generating electricity. The majority of the energy consumed by the US transportation sector is...
The purpose of this study was to identify antimutagens in yogurt active against the
experimental colon carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Our
initial experiments showed that acetone extracts of yogurt, or milk fermented by various
lactic acid bacteria were antimutagenic against MNNG and 3,2'-dimethyl-4-aminobiphenyl
(DMAB) in the Ames test (Salmonella typhimurium TA...
In an effort to understand the basis for sulfite detoxification in S. cerevisiae,
the functions of two genes were analyzed. SSU1, which encodes a plasma membrane
protein, was found to be required for efficient sulfite efflux. FZFl-4, a dominant
allele of a transcriptional activator of SSUl, was also found to...
Sequence-specific PCR markers were derived from one new and eight previously identified random amplified polymorphic DNA (RAPD) markers for the purpose of identifying grape (Vitis) rootstocks. The markers were developed because the RAPD assay was found to be inconsistent and the original RAPD markers unreliable. Southern hybridization analysis of the...
Sulfite mutants representing five complementation groups, previously derived from
an ethyl methanesulfonate-treated haploid strain of Saccharomyces cerevisiae were studied.
Although the wildtype S. cerevisiae strain used (isogenic to X2180-1 A) had a basal
tolerance for sulfite (7 μM free H₂SO₃), the sensitive and resistant mutants were found to
tolerate less...
A number of methods to isolate and quantify protein in Pinot noir wines were evaluated. The combination of precipitation by acetone containing 10% w/v trichloroacetic acid followed by quantification with the Bradford assay, reported in yeast invertase equivalents yielded the most accurate results when compared to micro-Kjeldahl analysis. The technique...
Yeast mannoproteins released during the process of aging wine on the yeast lees have been reported to make important contributions to wine quality. However, few mannoproteins have been identified in wine and their lifespan during aging is unknown. As a first step towards better understanding the contributions of yeast mannoproteins...
Objectives:
1. Isolation or construction of an acid protease-excreting laboratory strain of Saccharomyces
cerevisiae.
2. Evaluation of enzyme activity against model protein, protein-tannin, and grape protein substrates.
3. Selection or screening of isolates producing greater enzyme activity with improved specificity.
4. Construction of an acid protease-excreting wine strain of Saccharomyces...
Correct identification of grapevines is of extreme importance to the expanding U.S. viticulture and wine industries. Several recent cases of misidentifications have occurred because the tools for accurate typing of plants are either inadequate or lacking. We have been applying one type of DNA-based procedure that has shown great promise...
Hydrogen sulfide and related sulfur compounds produced internally by yeast during fermentation are considered highly undesirable if they are excreted and exceed threshold concentrations in the finished wine, as they cause an unpleasant "reduced character". The threshold for hydrogen sulfide is on the order of parts per billion and that...
1-Phenyl-3-(2-Thiazoly1)-2-Thiourea (PTTU), has been reported to
inhibit dopamine-fi-hydroxylase (a copper-containing enzyme involved in
the pathway of biosynthesis of adrenaline in animal systems). In the
present study, PTTU has been shown to have cytokinin activity in the
tobacco bioassay. The cytokinin activity of PTTU suggested that
cytokinin-active N⁶-substituted adenine derivatives might...
Cytokinins are plant hormones regulating cell division and differentiation.
Most developmental events from germination, vegetative morphogenesis to seed
and fruit set are influenced by cytokinins. t,ns-Zeatin is the major natural
occurring cytokinin. Its isomer, cis-zeatin, and its derivatives are usually present in
low quantities and have traditionally been considered as...
One of the most common problems in wine production is the formation of hydrogen sulfide (H₂S) and other volatile sulfur compounds (VSCs), which can mask positive aromas at low concentrations and result in unpleasant aromas such as rotten egg, cabbage, garlic, and rubber at higher concentrations. Despite the large body...
Studies reporting on potentially toxic interactions between aqueous fullerene nanoparticles (nC₆₀) and
microorganisms have been contradictory. When known confounding factors were avoided, growth yields of
Saccharomyces cerevisiae and Escherichia coli cultured in the presence and absence of independently prepared
lots of underivatized nC₆₀ were found not to be significantly different.
'Golden Delicious' winter squash (GDWS), Cucurbita maxima Duchesne, provides significant amounts of pollen (24 mg) and nectar (236 μl), but with a low reward of 14% nectar sugar. The quantity of nectar produced per GDWS flower differed between sites and floral sex. The GDWS male flowers had 25% higher sugar...
Moderate wine consumption, particularly pigment-rich red wine, is thought by many to be beneficial for the cardiovascular system. Both ethanol and phytochemicals are thought to contribute to this cardioprotective property. Metabolic disturbances associated with overconsumption of food are related to the initiation and progression of many chronic diseases, and cardiovascular...
Peptide-phosphorodiamidate morpholino oligomers (PPMOs) are synthetic DNA mimics that bind and silence gene targets. Through designing PPMOs that silence essential or resistance genes in pathogens, these antisense oligomers could be utilized as novel antimicrobials. Towards this end, my thesis employed minimum inhibitory concentration assays (MICs) to identify PPMOs capable of...
Contaminants can exist in a wide range of states in aqueous environments, especially in surface waters. They can be freely dissolved or associated with dissolved or particulate organic matter depending on their chemical and physical characteristics. The freely dissolved fraction represents the most bioavailable fraction to an organism. These freely...
The yeast Brettanomyces bruxellensis is the most important wines spoilage yeast encountered during winemaking as it can survive in wine for long periods, requires minimal nutrients for growth, and can be difficult to control. Brettanomyces produces two major spoilage products, the volatile phenols 4-ethylphenol (Band-Aid, medicinal smell) and 4-ethylguaiacol (smoke,...
The research described in this thesis was aimed at understanding how particle size, porosity, and enzyme accessible surface area influence the rate of saccharification of microcrystalline cellulose. Microcrystalline cellulose (MCC) is a commonly used substrate for the study of cellulolytic enzymes. MCC preparations of different particle size are commercially available....
Pesticides are among the most pervasive environmental contaminants and they are an important potential risk for human health. Agricultural workers are constantly exposed to pesticide spray, drift and residues in the soil and foliage. Many agricultural pesticides are readily absorbed by the body, through contact with the skin, the respiratory...
Successful cell division requires proper chromosome movement, including accurate congression to the metaphase plate and proper segregation to spindle poles. Errors that occur in either event can cause chromosome aneuploidy in daughter cells, which may lead to cell death, genetic diseases and cancers (Matson and Stukenberg,2012, Compton, 2000). The force...
Pergamasus quisquiliarum Canestini is a polyphagous predatory mite that has been shown to feed on the economically important arthropod, Scutigerella immaculata Newport (Symphyla: Scutigerellidae), Collembola, Diptera larvae, Enchytraeid worms, and miscellaneous other soil organisms. This study examined the feeding behavior of P. quisquiliarum, the effects of cover cropping and tillage...
This research investigated yeast populations and diversity during pre-fermentation cold maceration and alcoholic fermentation of Vitis vinifera L. cv. Pinot noir grapes from a commercial vineyard (Dayton, OR). Fermentations were conducted at the Oregon State University research winery in 100 L tanks while grapes from the same vineyard lot were...
This study reports finding of two rootstock experiments planted in 1997. The purpose of the first experiment was to evaluate the performance of Pinot noir on 19 phylloxera-resistant rootstocks and as an ungrafted vine. The purpose of the second experiment was to evaluate the performance of V. Vinifera cultivars Pinot...
This thesis summarizes an investigation into the need for removing extractives
from herbaceous biomass feedstocks prior to their chemical characterization. Switchgrass
(Panicum virgatum), was used in this study as a representative herbaceous biomass
feedstock. The influence of extractives on the chemical analysis of switchgrass was done
by comparing the composition...
A low, but significant, fraction of the carbohydrate portion of herbaceous biomass may be composed of fructose/fructosyl-containing components (“fructose equivalents”); such carbohydrates include sucrose, fructo-oligosaccharides, and fructans. Standard methods used for the quantification of structural-carbohydrate-derived neutral monosaccharide-equivalents in biomass are not particularly well suited for the quantification of fructose equivalents...
SAR11 Alphaproteobacteria are the most abundant aerobic chemoheterotrophs in ocean surface waters. Previous studies have indicated SAR11 cells play an important role in marine carbon cycling and consume up to half of some common dissolved organic compounds, such as amino acids. During sequencing of the first SAR11 genome, genes for...
Metabolomics is a comprehensive analysis of small molecules, or metabolites, in a system. Metabolomics is a hypothesis-generating experiment and offers an unbiased analysis of cell metabolism that can aid in the understanding of fundamental biological processes. Metabolomics is widely and broadly applicable in the biological sciences and has been used...
The objectives of this research project are to gain a better understanding of juice/must nutrition and the production of hydrogen sulfide and other 'off' sulfide odors in Oregon wines in relationship to both viticulture and winemaking practices. Specifically, the objectives of this research project are: · To analyze commercial juices/musts...
The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that is a member of the basic helix-loop-helix PER-ARNT-SIM (bHLH/PAS) protein family of cellular sensors. The AHR is conserved across multiple animal phyla and is required for proper vertebrate development. A structurally diverse group of chemicals, including polycyclic aromatic...
Many members of the Phylum Cnidaria are mutualistic with unicellular dinoflagellates belonging to the genus Symbiodinium. Corals are the most widely recognized example of these associations due to their key ecological importance in coral reef ecosystems where they serve as the structural and trophic foundation of these rich ecosystems. Coral...
This thesis is an account of investigation on the natural products deriving from various marine algae and has resulted in the discovery of eleven novel bioactive metabolites. Isolation and characterization of these new molecules were carried out using different chromatographic techniques and by analyses of different spectroscopic data, respectively. Using...
Metabolic syndrome is a problem affecting people around the world. In a number of studies, soy intake has been documented to possess antidiabetic and anticardiovascular effect. My project is focused on the impact of the intake of compounds found within soy, the isoflavones, their impact on metabolic syndrome symptoms, and...
The efficiency of cellulose hydrolysis under straight saccharification and simultaneous saccharification and fermentation (SSF) conditions was evaluated using three lignocellulosic materials (switchgrass, cornstover, and poplar), which had been pretreated with dilute sulfuric acid under conditions which optimized xylose concentrations in the prehydrolysate liquid. Yields of glucose, cellobiose and ethanol obtained...
Oysters are filter-feeding bivalves, which filter water for nutrients and often accumulate contaminants and human pathogens such as Vibrio parahaemolyticus and Vibrio vulnificus naturally occurring in the marine environment. These naturally occurring pathogens have been frequently isolated from raw shellfish, particularly oyster, in the United States and are recognized as...
The enterotoxin-producing Clostridium perfringens type A isolates are responsible for the third most common foodborne illness in the United States and can also cause non-foodborne human gastrointestinal (GI) diseases such as antibiotic- associated and sporadic diarrheas. Three important factors contribute to the ability of C. perfringens to cause GI diseases,...
Lichens are an important part of the biota in western Oregon forests, where
they perform valuable ecological roles and contribute significantly to biodiversity.
Lichens in western Oregon are threatened by a number of factors including air
pollution and land use practices. If we wish to maintain the persistence of lichens...
The objectives of this project were to evaluate the efficacies of electrolyzed oxidizing (EO) and ozonated waters as antimicrobial agents for enhancing the microbiological safety of fresh strawberries (Fragaria x ananassa). The influence of sodium chloride (NaCl) concentrations used for preparing EO water was evaluated on their bactericidal activities against...
Lignocellulosic biomass represents a vast supply of fermentable carbohydrates and functional aromatic compounds. Conversion of lignocellulosics to ethanol and other useful products would be of widespread economical and environmental benefit. Better understanding of the behavior of different lignicellulosic feedstocks in fermentation protocols as well as catalytic activities involved in lignocellulosic...
The aim of this study was to gain more information about the
interactions between DNA and the histone octamer during the
process of transcription. This work used a pUC8 plasmid derivative
that contained the core promoter region of the RNA polymerase I of
Acanthamoeba castellanii, placed upstream of four repeats...
Previous studies have shown that rainbow trout exposed to dieldrin via diet for 9 to 12 weeks increased biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500%. This was not explained by induction of the cytochrome P-450 (CYP) system involved in oxidative metabolism of these compounds. We hypothesized that...