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.