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More than 30 members of the diverse amphidinolide family of biologically active macrolides have been isolated over last three decades. From this family, amphidinolides C and F stand among the most complex ...
Citation Citation
- Title:
- Computational study on proline sulfonamide-catalyzed aldol reaction
- Author:
- Mahapatra, Subham
More than 30 members of the diverse amphidinolide family of biologically active macrolides have been isolated over last three decades. From this family, amphidinolides C and F stand among the most complex and densely functionalized affiliates. Recently, we have accomplished the first total synthesis of amphidinolide F. The all-carbon framework of amphidinolide C has been synthesized. During endeavor toward the total syntheses of amphidinolides F / C, we have uncovered a "hidden symmetry element" present in the northern and southern domains of amphidinolides F / C. The southern C₁-C₈ and northern C₁₈-C₂₅ tetrahydrofuran segments were derived from a common intermediate. A scalable silver-catalyzed isomerization / cyclization on propargyl-benzoate / diol furnished the common intermediate in multigram quantity. The common intermediate provided access to over half of carbon backbone of the macrocycle as well as majority of stereochemistry present in amphidinolides F / C. Two strategically different techniques have been developed for the C₉-C₁₁ diene preparation. A metal-catalyst free Weinreb amide-vinyl lithium coupling / methylenation sequence furnished the diene motif. Alternately, diastereoselective addition of a dienyl iodide derived 2-lithio-1,3-diene species to an α-oxy aldehyde installed the C₉-C₁₁ diene and secured the C₈ stereochemistry in single operation. The dienyl iodide was prepared via a regioselective hydrostannylation on an enyne. A challenging alkylation between an α-branched sulfone and an α-silyloxy iodide generated the all-carbon frameworks of amphidinolides F / C. An efficient oxidative desulfurization incorporated the carbonyl moiety at C₁₅. The protecting group on C₁₈ alcohol was found to have significant effect on the sulfone-iodide alkylation / oxidative desulfurization sequence. Installation of chelating ethoxyethyl ether on C₁₈ alcohol helped the successful incorporation of C₁₅ ketone and solved the deprotection problem in advanced stage of synthesis. A detailed analytical and computational study on proline sulfonamide-catalyzed aldol reactions has been performed. The pKa value of a proline sulfonamide catalyst was determined experimentally via NMR titration technique. Computational study revealed the origin of enhanced stereoselectivity by proline sulfonamide catalysts over parent proline. The non-classical hydrogen bonding interactions were found to be responsible for improved diastereoselectivity.
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This study examined the financial management practices of a group of middle and upper class retired couples in a period of rising prices and relatively fixed incomes. The objective of this study was to ...
Citation Citation
- Title:
- Financial management practices of a selected group of retired couples
- Author:
- Pulley, Mary Ann
This study examined the financial management practices of a group of middle and upper class retired couples in a period of rising prices and relatively fixed incomes. The objective of this study was to describe (1) financial planning of retired couples, (2) expenditures of these couples, (3) adjustments of their expenditures to income, (4) place of credit in their financial management, (5) financial management problems faced since retirement, and (6) feeling about their financial position. The data were obtained from a sample of 50 couples who considered themselves retired. They lived in an adult community near Portland, Oregon, owned or were buying a single-family dwelling and were willing to cooperate in the study. The 50 couples were interviewed in their homes during the summer of 1971. The age of the husbands at retirement ranged from 52 to 79 with a mean age of 64.8. The mean number of year retired was seven. Based on Hollingshead's Two-factor Index of Social Position, all the husbands were from the middle or upper social positions. In 1970, incomes of the couples ranged from $2,000 to $40,000 with a median of $8,400. Their net worth ranged from $23,000 to over $200,000 with a median of $80,000. All couples reported enough income for current needs. Forty-eight couples indicated they had adequate provision for an extended illness and sufficient income to visit children and relatives as often as they wished. Forty-six couples lived close enough to their pre-retirement level of living to please them. Thirty-nine of the couples used a financial plan, but only five couples had made written plans. Most couples based their financial plan on past experiences and adjusted their plan as needs changed. Those with a financial plan usually planned for a month or a longer period. All couples reported some degree of flexibility in their plans. Thirty-eight of the 45 couples who at some time had used a financial plan felt it had been an aid to a higher level-of-living than would have been possible without a plan. The total expenditures of the 50 couples in 1970 ranged from $2,695 to $20,264 with a mean of $8,287. By income level the mean total expenditures were: $4,255 for the $5,000 or less income group; $7,973 for the $5,001 to $10,000 group; $10,753 for the $10,001 to $15,000 group; and $13,570 for the group with income of $15,001 or more. The expenditures represent dissavings in the two lower income groups in decreasing amounts as income increased. Savings in the two upper income groups increased in amounts as income increased. The mean 1970 expenditures for all couples were: food, $1,450; housing, $1,538; transportation, $1,213; clothing and clothing care, $327; medical, $571; other family consumption, $1,414; gifts and contributions, $391; life insurance, $224; and personal taxes, $1,147. When asked about adjustments of expenditures to income, 35 couples reported they had made adjustments to increasing costs in 1970. All couples used their time, energy or skills as substitutes for purchased services. The services performed and named in order of frequency of substitution were: laundering, cleaning, making minor household repairs and doing maintenance work. Ninety-eight percent of the couples found satisfaction in performing these services. Forty-seven of the 50 couples used credit in 1970. Credit cards were used by 40 couples and monthly charge accounts by 24 couples. The items most frequently purchased on credit in 1970 were gas and oil followed by clothing and household items. Only three couples reported financial management problems after retirement. The problems reported were: having children in school after retirement; selling home to buy in a more desirable neighborhood; receiving reduced income from investments; and supporting an aged parent in a nursing home.
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153. [Image] Vegetation and fire history of Ponderosa Pine - White Fir forest in Crater Lake National Park
ill., maps; Typescript (photocopy); Thesis (M.S.)-Oregon State University, 1975; Includes bibliographical references (leaves 120-127)Citation Citation
- Title:
- Vegetation and fire history of Ponderosa Pine - White Fir forest in Crater Lake National Park
- Author:
- McNeil, Robert Curlan
- Year:
- 1975, 2009, 2010
ill., maps; Typescript (photocopy); Thesis (M.S.)-Oregon State University, 1975; Includes bibliographical references (leaves 120-127)
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The stereospecific reagent-controlled homologation (StReCH) of boronic esters with putative lithiooxiranes generated in situ from appropriate precursors via sulfoxide-lithium exchange, tin-lithium exchange, ...
Citation Citation
- Title:
- Chain extension of boronic esters with stereo- and regio-defined lithiated oxiranes
- Author:
- Alwedi, Embarek
The stereospecific reagent-controlled homologation (StReCH) of boronic esters with putative lithiooxiranes generated in situ from appropriate precursors via sulfoxide-lithium exchange, tin-lithium exchange, and direct lithiation is described with an emphasis on the first lithiation technique which allows for the regio- and stereo-specific generation of all types of lithiooxirane isomer. Transient lithiooxiranes[LiCR²(O)CR³R³'] react at low temperature (≤ –30 °C) with boronic esters [R⁰B(OR')₂] to give intermediate ate-complexes that experience 1,2-metallate rearrangement upon warming to room temperature to give chain extended β-alkoxy boronates [R³R³'C(OLi)R⁰R²CB(OR')₂]. Providing the lithiooxirane maintains configurational stability on the time-scale of its interception by the boronic ester, such reactions are anticipated to give anti-like boronate products from cis-lithiooxiranes and syn-like boronate products from trans-lithiooxiranes. Three methods were evaluated to prepare stereodefined scalemic sulfinylepoxides [p-TolS(O)CR²(O)CR³R³'] from enantioenriched sulfoxide containing precursors: (i) a Darzens-type condensation of α-chlorosulfoxides [p-TolS(O)CHR²Cl, R² = H or Me] with aldehydes or ketones, (ii) basic hydrogen peroxide mediated nucleophilic epoxidation of (E)- and (Z)-vinylsulfoxides [p-TolS(O)CR²=CR³R³'] formed via Horner-Wadsworth-Emmons olefination, and (iii) multi-step epoxide formation from the same vinylsulfoxides via vicinal halohydrin formation followed by cyclization. Method (i) led to the production of separable mixtures of cis- and trans-sulfinylepoxides in good overall yield (67-87%, cis:trans ~ 6:1): for non-enolizable carbonyl compounds, epoxide formation mediated by t-BuOK base occurred spontaneously in a single-pot mode; however, a two-step protocol involving LDA mediated chlorohydrin formation followed by t-BuOK mediated cyclization was required to access sulfinylepoxides from enolizable carbonyl compounds. Partial racemization of the α-chlorosulfoxide starting material accompanied epoxide formation via each variant of method (i) (chlorosulfoxide %ee ≥ 95% vs. sulfinylepoxide %ee ~ 85%). Methods (ii) and (iii) were less expedient but resulted in the formation of pure cis-epoxides from cis-vinylsulfoxides and pure trans-epoxides from trans-vinylsulfoxides. Little, if any, racemization accompanied methods (i) and (ii). 3-Substituted sulfinylepoxides were easily obtained from all three methods; however, the formation of unsubstituted and 2-substituted sulfinylepoxides, 2,3-disubstituted, and 2,3,3-trisubstituted sulfinylepoxides could only be successfully achieved via method (i). Lithiooxiranes [LiCR²(O)CR³R³', R² = H or Me; R³/R³'= H/Me, H/n-Pr, H/Ph, H/t-Bu, or Me/Ph] generated by sulfoxide-lithium exchange from the stereodefined sulfinylepoxides (using PhLi or t-BuLi, THF, ≤ –90 °C) were employed for StReCH of boronic esters R⁰-Bpin (R⁰ = BnCH₂, allyl, c-C₆H₁₁, Ph). Addition of TBSOTf to the intermediate ate-complexes gave β-silyloxyboronates which could be converted to vicinal diol monosilylethers upon oxidative work-up with aq. NaOOH. The 2°/2° (4-32%, dr > 98:2), 2°/3° (21-66%, dr ≥ 65:35), and 3°/3° (59-68%, dr ≥ 95:5) vicinal stereodiad containing compounds created in this manner were typically obtained in a highly stereocontrolled manner. In general, and as expected, cis-sulfinylepoxides afforded anti-like stereodiads while trans-sulfinylepoxides gave instead syn-like stereodiads. A deuterium labeling study revealed that sulfinylepoxides with α-H-atoms give StReCH products in low yield (≤32%) because of proton exchange between the transient basic lithiooxirane and its acidic sulfoxide precursor. Due to its apparent configurational instability, LiCMe(O)CHPh afforded anti-like 2°/3° motifs regardless of the cis- or trans-stereochemistry of its sulfinylepoxide precursor. Significant quantities (15-25% yield) of stereochemically pure (E)- or (Z)-tetrasubstituted alkene by-products accompanied the formation of β-hydroxyboronate products from 2,3,3-trisubstituted sulfinylepoxides. The stereochemistry of products was established by NMR spectroscopic (including nOe studies of acetonides derived from vicinal diols) and single-crystal X-ray diffraction methods. Tin-lithium exchange from 2-(tributylstannyl)oxirane was explored as a means to generate the parent lithiooxirane for StReCH of boronic esters. (±)-2-(Tributylstannyl)oxirane was prepared by addition of vinylmagnesium bromide to n-Bu₃SnCl following by m-CPBA mediated epoxidation of the resulting vinyl stannane. Jacobsen's hydrolytic kinetic resolution (HKR) procedure failed to resolve this epoxide and subsequent StReCH studies were conducted with its racemate. Treatment of mixtures of a boronic ester R⁰-Bpin (R⁰ = BnCH₂, allyl) and n-Bu₃SnCH(O)CH₂ with n-BuLi (THF, –90 °C) followed by the addition of TBSOTf and TMEDA, resulted in the formation of the expected chain extended products [TBSOCH₂CHR⁰Bpin] in excellent yield (≥81%).This process was applied to an enantiodivergent synthesis of the carbon skeletons of the pyrrolizidine alkaloids (–)-hastanecine and (+)-dihydroxyheliotridane. Thus, B-allyl pinacol boronate was chain extended with (±)-lithiooxirane using the above method and the resulting racemic β-siloxyboronate further homologated with the enantiopure trans-lithiooxirane generated by deprotonation of (S)-2-[(tert-butyldimethylsilyloxy)ethyl]oxirane with LiTMP (THF, –30 °C). Oxidative work-up afforded a pair of enantiopure epimeric carbinols (in an overall unoptimized yield of 13%) containing all carbon-atoms of the target alkaloids.
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155. [Article] Simplified Reversed Chloroquines to Overcome Malaria Resistance to Quinoline-based Drugs
Malaria is a major health problem, mainly in developing countries, and causes an estimated 1 million deaths per year. Plasmodium falciparum is the major type of human malaria parasite, and causes the most ...Citation Citation
- Title:
- Simplified Reversed Chloroquines to Overcome Malaria Resistance to Quinoline-based Drugs
- Author:
- Gunsaru, Bornface
- Year:
- 2010
Malaria is a major health problem, mainly in developing countries, and causes an estimated 1 million deaths per year. Plasmodium falciparum is the major type of human malaria parasite, and causes the most infections and deaths. Malaria drugs, like any other drugs, suffer from possible side effects and the potential for emergence of resistance. Chloroquine, which was a very effective drug, has been used since about 1945, but its use is severely limited by resistance, even though it has mild side effects, and is otherwise very efficacious. Research has shown that there are chloroquine reversal agents, molecules that can reinstate antimalarial activity of chloroquine and chloroquine-like drugs; many such reversal agents are composed of two aromatic groups linked to a hydrogen bond acceptor several bonds away. By linking a chloroquine-like molecule to a reversal agent-like molecule, it was hoped that a hybrid molecule could be made with both antimalarial and reversal agent properties. In the Peyton Lab, such hybrid "Reversed Chloroquine" molecules have been synthesized and shown to have better antimalarial activity than chloroquine against the P. falciparum chloroquine-sensitive strain D6, as well as the P. falciparum chloroquine-resistant strains Dd2 and 7G8. The work reported in this manuscript involves simplifying the reversal agent head group of the Reversed Chloroquine molecules, to a single aromatic ring instead of the two rings groups described by others; this modification retained, or even enhanced, the antimalarial activity of the parent Reversed Chloroquine molecules. Of note was compound PL154, which had IC50 values of 0.3 nM and 0.5 nM against chloroquine-sensitive D6 and chloroquine-resistant Dd2. Compound PL106 was made to increase water solubility (a requirement for bioavailability) of the simplified Reversed Chloroquine molecules. Molecular modifications inherent to PL106 were not very detrimental to the antimalarial activity, and PL106 was found to be orally available in mice infected with P. yoelli, with an ED50 value of about 5.5 mg/kg/d. Varying the linker length between the quinoline ring and the protonatable nitrogen, or between the head group and the protonatable nitrogen, did not have adverse effects on the antimalarial activities of the simplified Reversed Chloroquine molecules, in accord with the trends observed for the original design of Reversed Chloroquine molecules as found from previous studies in the Peyton Lab. The simplified Reversed Chloroquine molecules even tolerated aliphatic head groups (rather than the original design which specified aromatic rings), showing that major modifications could be made on the Reversed Chloroquine molecules without major loss in activity. A bisquinoline compound, PL192, was made that contained secondary nitrogens at position 4 of the quinoline ring (PL192 is a modification of piperaquine, a known antimalarial drug that contains tertiary nitrogens at position 4 of the quinoline ring); this compound was more potent than piperaquine which had an IC50 value of 0.7 nM against CQS D6 and an IC50 of 1.5 nM against CQR Dd2, PL192 had IC50 values of 0.63 nM against chloroquine sensitive D6 and 0.02 nM against chloroquine resistant Dd2. Finally, the mechanism of action of these simplified "Reversed Chloroquines" was evaluated; it was found that the simplified "Reversed Chloroquines" behaved like chloroquine in inhibiting β-hematin formation and in heme binding. However, the simplified "Reversed Chloroquines" were found to inhibit chloroquine transport for chloroquine resistant P. falciparum chloroquine resistance transporter expressed in Xenopus oocytes to a lesser extant than the classical reversal agent verapamil. From these studies it was noted that the simplified "Reversed Chloroquines" may not behave as well as classical reversal agents would in restoring chloroquine efficacy, but they are very potent, and so could be a major step in developing drug candidates against malaria.
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156. [Article] TonB-dependent outer-membrane proteins of Pseudomonas fluorescens : diverse and redundant roles in iron acquisition
Pseudomonas is a diverse genus of Gram-negative bacteria that includes pathogens of plants, insects, and humans as well as environmental strains with no known pathogenicity. Pseudomonas fluorescens itself ...Citation Citation
- Title:
- TonB-dependent outer-membrane proteins of Pseudomonas fluorescens : diverse and redundant roles in iron acquisition
- Author:
- Hartney, Sierra Louise, 1980-
Pseudomonas is a diverse genus of Gram-negative bacteria that includes pathogens of plants, insects, and humans as well as environmental strains with no known pathogenicity. Pseudomonas fluorescens itself encompasses a heterologous group of bacteria that are prevalent in soil and on foliar and root surfaces of plants. Some strains of P. fluorescens suppress plant diseases and the genomic sequences of many biological control strains are now available. I used a combination of bioinformatic and phylogenetic analyses along with mutagenesis and biological assays to identify and compare the TonB-dependent outer-membrane proteins (TBDPs) of ten plant-associated strains of P. fluorescens and related species. TBDPs are common in Gram-negative bacteria, functioning in the uptake of ferric-siderophore complexes and other substrates into the cell. I identified 14 to 45 TBDRs in each strain of P. fluorescens or P. chlororaphis. Collectively, the ten strains have 317 TBDPs, which were grouped into 84 types based upon sequence similarity and phylogeny. As many as 13 TBDPs are unique to a single strain and some show evidence of horizontal gene transfer. Putative functions in the uptake of diverse groups of microbial siderophores, sulfur-esters, and other substrates were assigned to 28 of these TBDP types based on similarity to characterized orthologs from other Pseudomonas species. Redundancy of TBDP function was evident in certain strains of P. fluorescens, especially Pf-5, which has three TBDPs for ferrichrome/ferrioxamine uptake, two for ferric-citrate uptake and three for heme uptake. Five TBDP types are present in all ten strains, and putative functions in heme, ferrichrome, cobalamin, and copper/zinc uptake were assigned to four of the conserved TBDPs. The fluorescent pseudomonads are characterized by the production of pyoverdine siderophores, which are responsible for the diffusible UV fluorescence of these bacteria. Each of the ten plant-associated strains of P. fluorescens or P. chlororaphis has three to six TBDPs with putative roles in ferric-pyoverdine uptake (Fpv). To confirm the roles of the six Fpv outer membrane proteins in P. fluorescens Pf-5, I introduced deletions into each of the six fpv genes in this strain and evaluated the mutants and the parental strain for heterologous pyoverdine uptake. I identified at least one ferric-pyoverdine that was taken up by each of the six Fpv outer-membrane proteins of Pf-5. By comparing the ferric-pyoverdine uptake assay results to a phylogenetic analysis of the Fpv outer-membrane proteins, I observed that phylogenetically-related Fpv outer-membrane proteins take up structurally-related pyoverdines. I then expanded the phylogenetic analysis to include nine other strains within the P. fluorescens group, and identified five additional types of Fpv outer-membrane proteins. Using the characterized Fpv outer-membrane proteins of Pf-5 as a reference, pyoverdine substrates were predicted for many of the Fpv outer-membrane proteins in the nine other strains. Redundancy of Fpv function was evident in Pf-5, as some pyoverdines were recognized by more than one Fpv. It is apparent that heterologous pyoverdine recognition is a conserved feature, giving these ten strains flexibility in acquiring iron from the environment. Overall, the TBDPs of the P. fluorescens group are a functionally diverse set of structurally-related proteins present in high numbers in many strains. While putative functions have been assigned to a subset of the proteins, the functions of most TBDPs remain unknown, providing targets for further investigations into nutrient uptake by P. fluorescens spp.. The work presented here provides a template for future studies using a combination of bioinformatic, phylogenetic, and molecular genetic approaches to predict and analyze the function of these TBDPs.
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157. [Article] Evolutionary Genomic Responses to Mitochondrial Dysfunction in Caenorhabditis elegans
Understanding the impact of mitochondrial dysfunction on genome evolution has the potential not only to provide new insights on the basic evolutionary processes influencing mitochondrial and nuclear genomes, ...Citation Citation
- Title:
- Evolutionary Genomic Responses to Mitochondrial Dysfunction in Caenorhabditis elegans
- Author:
- Wernick, Riana I.
Understanding the impact of mitochondrial dysfunction on genome evolution has the potential not only to provide new insights on the basic evolutionary processes influencing mitochondrial and nuclear genomes, but may also reveal novel avenues for evolutionary adaptive recovery from harmful mutations. Aberrant mitochondrial activity is fundamental to the pathology of mitochondrial diseases in addition to neurodegenerative disorders. While the effects of mitochondrial dysfunction have received much attention, less is known about their impact on genome evolution and potential target mechanisms for ameliorating the harmful effects of mitochondrial impairment. Characterizing genome modifications in animal populations predisposed to mitochondrial dysfunction may identify novel genes, mechanisms, and physiological pathways to target for recovery and provides a genome-wide perspective on the impact of aberrant mitochondrial activity. This dissertation research investigates how mitochondrial and nuclear genomes evolve in organisms genetically predisposed to mitochondrial dysfunction and contrasts genomic evolution in large and small population sizes. This work furthers understanding of the impact of evolutionary forces which influence genome evolution in population with reduced fitness, and reveals new insights into genomic responses to mitochondrial dysfunction. Chapters 2 and 3 of this dissertation focus on genome evolution using a set of mitochondrial respiratory chain mutant (gas-1¬ strain) and wild-type (N2 strain) Caenorhabditis elegans mutation-accumulation (MA) lines that experienced single-worm bottlenecking. The N2 MA lines, derived from a previous experiment, were bottlenecked for 250 generations. The gas-1 MA lines were created for this research, and bottlenecked in the laboratory for a maximum of 50 generations. Chapter 2 investigates mitogenomic evolution and heteroplasmic inheritance patterns evolving under extreme drift in gas-1 and N2 MA lines. Chapter 3 analyzes nuclear genome evolution using this same set of gas-1 and N2 MA lines. In contrast, Chapter 4 provides a complementary perspective, analyzing mitochondrial and nuclear genome evolution in twenty-four gas-1 'recovery line' (RC) populations, evolved in large population sizes for sixty generations. Bioinformatic methods and computational simulations were applied to characterize and evaluate genome evolution and provide a comprehensive investigation of the impact of mitochondrial dysfunction within a population genetics framework. In Chapter 2 our results of inherited mitochondrial DNA (mtDNA) heteroplasmy are in alignment with predictions of theories where a small subset of mtDNA molecules from the parental generation repopulates the mitochondrial genome pool for the progeny. Comparisons between Chapter 2 and 4 suggest that in both gas-1 and N2 strains organelle genome copy number is elevated in an environment characterized with extreme genetic drift but is less impacted throughout evolution in large populations when the force of genetic drift is reduced. Investigation of nuclear genome evolution in Chapter 3 revealed putative beneficial nuclear mutations in bottlenecked gas-1 populations. Additionally, compared to the N2 MA lines, the gas-1 MA lines were also observed to have a greater number of mutations located within the gas-1 gene interaction network. These observations reveal new insights into the potential fitness landscape for beneficial mutation and how nuclear genome evolution differs when predisposed to mitochondrial dysfunction in an environment characterized by extreme genetic drift. In Chapter 4, focusing on evolution in large populations, we observed parallel and potentially compensatory mitochondrial mutations indicative of positive selection in the gas-1 RC lines. Identified at heteroplasmy levels near-fixation, these mtDNA mutations were located in genes predicted to physically interact with the gas-1 gene. As signatures of positive selection were not detected in the mitochondrial genomes of gas-1 MA lines analyzed in Chapter 2, this work suggests that the processes by which beneficial mtDNA mutations rise to homoplasmy within the population may be less likely to occur in small populations. Additionally, we determined the evolutionary rate of nuclear genome change in Chapter 4 to be three times slower than published mutations rate values for C. elegans suggesting the influence of purifying selection in RC lines. Given that a quarter of nuclear mutations were located in genes exhibiting interactions within two-degrees of gas-1 it is likely that positive selection also influenced nuclear genome evolution. Overall, this research demonstrates that although adaptation from harmful mutation may occur in small or large populations, the observed paths to evolutionary adaptive recovery involve different mechanisms and suggests that although an environment with pervasive genetic drift may permit the fixation of beneficial nuclear mutations, the processes by which beneficial mtDNA mutations rise to homoplasmy within the population may be less permissive.
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158. [Article] Rogue pod traits in Phaseolus vulgaris
Snap beans are the vegetable form of dry bean (Phaseolus vulgaris L.) with low fiber, stringless and round, succulent pods that are eaten in the immature stage. Seed companies commit significant resources ...Citation Citation
- Title:
- Rogue pod traits in Phaseolus vulgaris
- Author:
- Al-Bader, Noor
Snap beans are the vegetable form of dry bean (Phaseolus vulgaris L.) with low fiber, stringless and round, succulent pods that are eaten in the immature stage. Seed companies commit significant resources to maintaining purity and uniformity of snap bean cultivars. While some variability may be introduced through outcrossing (beans are highly self-pollinated but occasional outcrosses do occur) and mechanical mixes of seed, mutation may also play a role. For traits such as pod cross-section (round vs. oval or flat), pod wall fiber and pod suture fiber (strings), reversions from the snap bean phenotype (round, low fiber, stringless) to the dry bean phenotype (oval or flat, high fiber, stringy) may occur. The reversions occur at many times the background mutation rate and are called "rogues" in the industry. Many cultivars, both commercially released and OSU bred show rogue traits and in the OSU breeding program, lines are grown out and inspected for off types every year. Among the rogue traits, strings and oval pods are of greatest concern. The reversions of round and stringless pods are of the most economically costly phenomena. In the past century scientists have studied snap bean pod traits, including suture strings, ovals and increased pod wall fiber per se. Results reported by researchers are in conflict regarding the heritability and gene models, including specific gene(s) controlling the phenotypic traits of interests. In addition, the advent of new molecular tools allows us to examine the reversion phenomenon at the molecular level. In the present study, three major approaches were used to get at the rogue question. First, we observed the inheritance of traits of interest by collecting seed of 98 off type plants representing 11 cultivars and breeding lines. These plants were self-pollinated and grown and classified for phenotype over three generations. Results obtained from this study revealed that traits were initially segregating in every case, but families became increasingly fixed over time. However, observed segregation ratios failed to fit expected segregation ratios. In addition, some families that were nearly fixed still showed a few individuals of the opposite phenotype. From the selfing of individual plants, we saw skewed segregation ratios that did not fit previous published inheritance models, any classical Mendalian one or two gene models or the populations within varieties segregating in a similar manner. Analyzing phenotype data showed an association of string with low or moderately low fiber content, which is congruent with non-rogue fixed pods, while oval pods showed association to high or moderately high fiber content. The second avenue of research was to make controlled crosses to conduct tests of allelism and inheritance. The objective of inheritance crosses was to decipher the dominance-recessive relationships of strings and ovals. The test of allelism, by crossing two stringy off type plants was to determine if strings were controlled by the same or different loci in different genetic backgrounds. A test of inheritance, by crossing an off type to a parental plant (string by stringless), was made to shed light on the genetic model of the trait. Due to time limitations, only the first hybrid generation was grown, which revealed dominance for the stringless and round pod phenotype. The third research strategy was to initiate molecular analysis using genotyping by sequencing (GBS) of a pooled sample of stringless genotypes compared to a pooled set of stringy genotypes to find single nucleotide polymorphisms (SNPs) between the two groups that would suggest candidate gene(s) for string (or lack of string) formation. Ninety-six samples split into two genotype pools (stringy and stringless), both with low fiber content were sequenced. In the stringy pool 31,212 SNPs were initially found and 38,936 SNPs were found in the stringless pool. SNPs with low quality and probability, due to low read depth, and SNPs that did not have a high impact on the gene itself (high impact SNPs are those with altered start, stop or splice sites that change gene function) were removed. Forty-three SNPs in the stringless pool that differed from the reference genome and 41 in the stringy pool were annotated as candidate genomic regions of control. Due to the fact that off types within the same family showed a lack of homogeneity for the phenotypic data within varieties, the high impact polymorphisms could have been due to factors other than the trait of interest. None of our SNPs of interest were present in published candidate genes for pod suture strings, fiber, or pod shattering, but novel areas of the genome were identified. Using our SNP data and putative candidate regions that have been identified, expression in these regions can be analyzed to further refine the list of potential candidate gene(s) controlling strings.
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Prostate cancer is the second leading cause of cancer related death in American men. Epidemiologic studies suggest that cruciferous vegetable intake may lower the risk for many cancers, including prostate ...
Citation Citation
- Title:
- Prostate cancer prevention with broccoli : from cellular to human studies
- Author:
- Clarke, John D.
Prostate cancer is the second leading cause of cancer related death in American men. Epidemiologic studies suggest that cruciferous vegetable intake may lower the risk for many cancers, including prostate and colon. Isothiocyanates (ITC) are phytochemicals derived from cruciferous vegetables such as broccoli, Brussels sprouts, cauliflower, and cabbage that may have health promoting properties. Broccoli and broccoli sprouts are a good source of sulforaphane (SFN), a well studied chemopreventive ITC. SFN is known to inhibit histone deacetylase (HDAC) activity and alter epigenetic endpoints. A key factor in understanding the efficacy of SFN as a chemoprevention agent is to determine the metabolism, distribution and bioavailability of SFN, and the factors that alter these parameters. The present study was undertaken to provide further evidence that SFN can alter HDAC activity, alter prostate cancer cell proliferation, both in vitro and in vivo and expands our understanding of SFN metabolism and tissue distribution. We characterized the effects of SFN in normal (PrEC), benign hyperplasia (BPH1) and cancerous (LnCap and PC3) prostate epithelial cells. We observed that 15 µM SFN differentially induced cell cycle arrest and apoptosis in BPH1, LnCap and PC3 cells but not PrEC cells. SFN treatment also differentially decreased HDAC activity, and Class I and II HDAC proteins, increased acetylated histone H3 at the promoter for P21, induced p21 expression and increased tubulin acetylation in prostate cancer cells. In PrEC cells, SFN caused only a transient reduction in HDAC activity with no change in any other endpoints tested. Therefore, normal prostate cells were refractory to the cytotoxic and epigenetic effects of SFN. In order for SFN to be an effective chemopreventive agent it must be metabolized and reach target tissues. Nrf2 wild-type and Nrf2 knockout (Nrf2-/-) mice were treated with 5 or 20 µmoles of SFN, and SFN metabolites were detected in all tissues tested at 2 and 6 h in a dose dependent manner. Genotype only had marginal effects at 5 µmoles, whereas, at 20 µmoles the female Nrf2-/- mice had dramatically higher levels. The relative abundance of each metabolite was not strikingly different between genders and genotypes, although different ratios between tissues were observed. In the transgenic adenoma of the mouse prostate model dietary SFN, fed as freeze-dried broccoli sprouts, increased SFN content in the prostate and decreased the severity of prostate cancer at 12 and 28 weeks of age. In humans, the differences in metabolism of isothiocyanates between whole food and broccoli supplements have yet to be determined. Two separate human trials were conducted; the first was a randomized 7 day feeding study where subjects consumed either broccoli sprouts or a broccoli supplement, and the second study was a randomized single dose cross-over study with broccoli sprouts, followed by a washout period, then broccoli supplement. In plasma and urine, the total amounts of SFN and erucin (ERN) metabolites were greater and the peak concentration occurred sooner in subjects who consumed broccoli sprouts. Glutathione-S-transferase pi-1 polymorphisms did not affect ITC metabolism. Interconversion of SFN to ERN was observed. Histone deacetylase activity in peripheral blood mononuclear cells was inhibited only in subjects who consumed sprouts. In conclusion, these data provide evidence that SFN alters HDAC activity and protein acetylation in cancerous prostate cells but not normal prostate cells. For the first time we show that SFN is bioavailable to many tissues types, including the prostate and are largely found as SFN metabolites not the parent SFN compound. We also show that the bioavailability of ITCs is markedly lower in human subjects who consume a broccoli supplement. Decreased HDAC activity in the peripheral blood of subjects who consumed sprouts indicates that higher ITC plasma concentrations can alter HDAC activity in vivo. Taken together, these data show that SFN is an effective prostate cancer chemopreventive agent that can easily be utilized in the diet from whole food.
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160. [Article] A comparative analysis of factors influencing smoking behaviors of college students, 1963-1987
Cigarette smoking continues to be one of the country's major health concerns. It has been defined as the single largest preventable cause of disease and death in the United States. Although research has ...Citation Citation
- Title:
- A comparative analysis of factors influencing smoking behaviors of college students, 1963-1987
- Author:
- Gray, Nancy L.
Cigarette smoking continues to be one of the country's major health concerns. It has been defined as the single largest preventable cause of disease and death in the United States. Although research has indicated that overall cigarette consumption has decreased in the nation over the past decades, cigarette smoking remains a significant problem among young people in the United States. This fact, coupled with studies indicating that cigarette smoking increases with age into the early twenties suggests that research should be conducted to determine those variables that encourage smoking behavior of late adolescents and young adults. The purpose of the study was to compare the relationship between selected predisposing factors and subsequent smoking behaviors exhibited in 1963 and 1987 respectively. Assessments of smoking behaviors of college students in Oregon in 1963-64 and 1986-87 were conducted to determine relationships between students smoking behaviors and selected socio-demographic variables. Comparisons were made between the resulting data for students in the 1963-64and 1986-87 studies. Aquestionnaire relating to smoking behavior was developed and administered to 3,786 college students attending introductory personal health classes during the 1963-64 school year at four selected colleges in the state of Oregon. During the 1986-87 school year a modified version of the questionnaire was developed and administered to college students attending introductory personal health classes at three of the same four universities that were utilized in the 1963-64 study. Stepwise logistic regression, chi square and descriptive statistics were used to analyze the data. Results indicated that there were significantly more smokers in 1963-64 and their daily consumption rates were significantly higher when compared to 1986-87 data. Although a larger percentage of females were smokers in the total population surveyed in 1963-64, there were more female smokers in the population of smokers in 1986-87. Whereas males consumed significantly more cigarettes per day than did females in 1963-64, there was no significant difference between male and female consumption rates in 1986-87. Significant numbers of smokers in 1986-87 started smoking at an earlier age than did smokers in 1963-64. When separating by gender, this was significant for females but not for males. Peer smoking was listed as the number one reason for starting to smoke by more than half of the respondents in 1986-87 as compared to 40% who listed curiosity in 1963-64. Physical reasons were indicated as the main reason for quitting by ex-smokers in 1963-64 and in 1986-87, over one half of the respondents indicated that they quit because of a concern for their physical health. Stepwise logistic regression equations were used to determine the set of variables that best accounted for smoking status in 1963-64 and 1986-87. Results indicated that the variables which predisposed individuals toward subsequent smoking behavior did differ when comparing the two studies. In 1963-64, an individual with the highest probability of smoking was one who had one or more older sisters who smoked, both parents smoked, father was a high school non-graduate and was from an urban setting. The individual with the lowest probability of smoking in 1963-64 had no older sisters who smoked, mother and father did not smoke, father was a high school graduate and lived in a rural setting. In 1986-87, the only variable to significantly increase the probability of an individual smoking was one or more older brothers who smoked. The following data were collected only for the 1986-87 population of students because questions relating to these issues were not included on the 1963-64 questionnaire. Use of alcohol, marijuana and smokeless tobacco by cigarette smokers was not significantly different when compared to non-smokers. Illicit substance use (cocaine, crack, heroin, quaaludes, etc) was significantly different for cigarette smokers and non-smokers. Smokers were more likely to use illicit substances than were non-smokers. The largest number of smokeless tobacco users were males in the 18-19 age category. Use of alcohol, marijuana and other illicit substances were significantly different for smokeless tobacco users than for non-users. Smokeless tobacco users were more likely to consume more alcohol on a weekly basis and use marijuana and illicit substances on an occasional and regular basis than were non-users of smokeless tobacco.