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Chemistry Seminar Series

CHEMISTRY SEMINAR SERIES Spring 2004

Seminars are scheduled on Fridays from 3:00 PM to 4:00 PM in Keyes 105 unless stated otherwise
Every seminar will be followed by a short reception in Keyes 104

February 6

No seminar

February 13

Jennifer Koviach
Bates College

"The Ends and Means of Carboyhydrate Synthesis"

February 19

 

7 PM in Olin 1

Jim Gentile
Department of Biology at Hope College

"Carcinogens in the Environment: Separating Fact from Fiction"

Please note: Prof. Gentile will also be giving a Biology seminar, "Acquired Infectious Disease and Cancer" at 1 PM on Friday, Feb. 20 in Olin 01.

February 27

No seminar

March 5

Sharon Treat
Colby College

"What are they thinking? Science, politics and the legislative process"
Maine, like many states, prides itself on its part-time, citizen legislature.  But how well does a legislature made up of regular people and limited staff make decisions on complex issues that involve scientific and technical issues?  Do legislators have the information they need to make science-based decisions? And how should science affect legislative decisions?  Sharon Treat, Maine's Senate Majority Leader and an environmental attorney, explores how the legislative process intersects with science as legislative policymakers grapple with issues such as mercury in the environment, decommissoning nuclear power plants, reducing dioxin from paper mills, whether to ban the gasoline additive MTBE, and labeling of products such as genetically modified food and milk from cows treated with hormones.

 

March 12

Introduction to EndNote for Chemists

March 19

Spring Break, No Seminar

March 26

Spring Break, No Seminar

April 2

Sunhee Choi
Middlebury College

"Mechanistic Study of Pt(IV) Anticancer Complexes"

April 9

Senior Chemistry Presentations:

Roy, Eric

Analysis of Fe(III)-Desferrioxamine

A method was developed to detect the Fe(III)-Desferrioxamine complex at nanomolar concentrations in aqueous samples. Fe(III)-Desferrioxamine is very stable towards common reductants and is not photochemically active.   However, addition of the oxalate ligand did promote photochemical reduction of Fe(III)-Desferrioxamine by 256 nm light, probably through a photoactive, ternary complex.   The reduced iron was quantified using the colorimetric reagent ferrozine, producing an analytical signalthat can be quantified at 562 nm with a long pathlength flow cell.This method will be used as part of an iron nano-sensor designed to selectively detect bioavailable iron in marine environments.

 

 

Foley, Brian

Production of significant HOOH concentrations in the deep waters of temperate lakes

A continuous flow-injection based, chemiluminescence method was developed to measure H 2O2in Fe(II)-rich freshwater lakes. Vertical profiles of H2O2 concentrations in temperate, thermally stratified, lakes in central Maine exhibited a surface maximum of 600 nM and a deep maximum of 450 nM above the sediment-water interface. Diel cycling was observed for surface H2O2 consistent with photochemical production and biologically mediated decay.   The presence of high concentrations of H2O2 in suboxic waters is consistent with dark, abiotic formation of H2O2 from Fe(II) reduction of dissolved oxygen.   The formation of H2O2 in the deep water of lakes could have important implications for the redox equilibiria and kinetics of metals in the hypolimnion of many temperate lakes.

April 16

Senior Chemistry Presentations:

 

Poage, Graham M.

Phosphate chemistry of potential anticancer ruthenium compounds

The anticancer activity of both the cis- and trans- isomers of RuCl2(DMSO)4 have been documented by other laboratories.  Previous work in our laboratory has shown that cis-RuCl2(DMSO)4 undergoes an apparent dimerization reaction in the presence of inorganic phosphate, whereas the trans isomer does not.  In this work, each isomer of RuCl2(DMSO)4 was allowed to react with phosphate buffer under various reaction conditions and screened for products by reversed-phase HPLC.  Isolation and characterization of these products will be presented and discussed, particularly with relevance to attenuation of antitumor activity of the parent compounds.


Mojo, Jennifer A.

Overexpression and Purification of Three Cereal Grain Proteins

TaABF, TaWD40 and AFN1-3

Abstract: PKABA 1 is a protein kinase located within the abscisic acid (ABA) signaling pathway responsible for ABA-suppressed gene expression in cereal grains.   Three proteins have been found that interact with PKABA1.   TaABF and TaWD40 directly interact with PKABA1 in wheat cells.   AFN1-3, an oat protein, is believed to signal and initiate the early steps of seed germination.   In order to study the functional roles of these three proteins, large quantities of each protein needs to be produced.   To produce larger samples, colonies of E. coli containing plasmids with partial cDNA inserts of each protein were used to overexpress each fusion protein.   Nickel affinity columns were used to separate the fusion proteins from the E. coli proteins.   During the purification procedure, the 6x His-tag fusion proteins adhered to the column, while the E. coli proteins were removed with washes of various pHs.   In theory, the majority of the E. coli proteins are removed during the washes.   However, the purification and overexpression technique still need some improvement.

April 23

Senior Chemistry Presentations:
Collins, Meredith S.

Synthetic Approaches to a Highly Functionalized Indanone Metabolite

The densely functionalized indanone 1 is a naturally occurring metabolite isolated from the filamentous marine cyanobacterium Lyngbya majuscula. Compound 1 is known to be an in vitro inhibitor of the hypoxia-induced activation of the vascular endothelial growth factor (VEGF) gene promoter in Hep3B human liver tumor cells. It thus appears to have a role in affecting tumor angiogenesis. In this work, the progress made toward the total synthesis of 1 is described.


Romano, Keith P.

Reaction of epichlorohydrin and epibromohydrin with synthetic DNA oligomers.

            Epichlorohydrin (ECH) has a variety of industrial uses, including the manufacture of epoxy resins, agricultural pesticides, adhesives, and plastics. The structure of ECH suggests that it should act as a bifunctional alkylator of DNA, which could account for its mutagenic properties\ in humans.   We are using denaturing polyacrylamide gel electrophoresis (dPAGE) to investigate the reactivity of ECH and the related compound epibromohydrin (EBH) with synthetic DNA oligomers.   Both compounds produce a low-mobility band on denaturing gels consistent with an interstrand cross-link. This product is piperidine-cleavable, suggesting alkylation at N7 of guanine. Its rate of formation varies dramatically for ECH and EBH, with the ECH reaction showing a marked pH-dependence. Our research may ultimately shed light on the way in which ECH and similar epoxides disrupt cellular systems.  


Olenick, Laura L.

Synthesis of a tetradentate sulfur ligand and new biomimetic molybdenum complexes of that ligand

The syntheses of novel biomimetic sulfur-ligated complexes that are potential models for metalloenzymes, such as molybdenum oxidases, are being pursued. These complexes can be used to determine the basic inorganic chemistry of a metal ion in a similar ligand environment to the appropriate metalloenzyme.  The target complexes will incorporate the new tetradentate bisthiolate, bisthioether ligand L that also contains two biphenyl groups.  The synthesis of L takes five steps and begins with biphenyl.  The synthesis and characterization of L will be discussed, along with any molybdenum complexes of this ligand that have been prepared.

April 30

Senior Chemistry Presentations:
Juskewitch, Justin E.

Mapping of Diepoxybutane Damage in the Cytochrome b Domain of Mitochondrial and the b -globin Domain of Genomic Chicken DNA Using Quantitative PCR

Diepoxybutane (DEB), a known industrial carcinogen, reacts with DNA primarily at the N7 position of deoxyguanosine residues and creates a variety of DNA adducts, including interstrand cross-links at the sequence 5'-GNC.   We are using a quantitative polymerase chain reaction (QPCR) to measure the amount of DEB damage (lesion frequency) within three different targets – mitochondrial (unpackaged) DNA, an open chromatin region, and a closed chromatin region.   Initial measurements of DEB damage within these three targets were not consistent because the template DNA was not the limiting reagent in the PCR.   Follow-up PCR trials using a limiting amount of DNA are still in progress although initial experiments looks promising.   Sequencing of these three targets to confirm the primer targets has only been successfully performed for the closed chromatin target and does not match the sequence from NIH used to design that primer pair.   Further sequencing trials need to be conducted on all three targets to assure that a mitochondrial, open chromatin, and closed chromatin region are actually being amplified in this experimental series.  


Goldberg, Jeffrey H.

A Laser Flash Photolysis Study of Dihalocarbenes in Room Temperature Ionic Liquids

There appears to be no report to date of the photochemistry of dihalocarbenes in room temperature ionic liquids (RTIL). This work will describe the results of time resolved laser flash photolysis (LFP) studies of selected dihalocarbenes, generated in RTIL, from the photolysis of precursors such as 1 and 2 . To understand the effect of the ionic media, carbene lifetimes determined in RTIL will be compared with known lifetimes obtained in conventional organic solvents.


Hayward, Jessica H.

Synthesis of a tetradentate sulfur ligand and new biomimetic nickel complexes of that ligand
 
  The syntheses of novel biomimetic sulfur-ligated complexes that are potential models for metalloenzymes, such as the nickel hydrogenases are being pursued. These complexes can be used to determine the basic inorganic chemistry of a metal ion in a similar ligand environment to the appropriate metalloenzyme.  The target complexes will incorporate the new tetradentate bisthiolate, bisthioether ligand L that also contains two biphenyl groups.  The synthesis of L takes five steps and begins with biphenyl.  The synthesis and characterization of L will be discussed, along with any nickel complexes of this ligand that have been prepared.

 

Seminar program coordinated by D. Whitney King

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Last Modified: 04/13/04 03:08:37 PM