All posts by cpage

Communicating Climate Science: Consensus Matters

Dr. Sarah Green, Professor
Department of Chemistry
Michigan Technological University
Date: April 22, 2016
Place: Chem-Sci Room 101
Time: 3:00 pm

Abstract

Climate science does not translate directly into political action to curb climate change. We are conducting a global experiment by modifying the basic chemistry, physics, and biology of the planet. Climate science explains past changes and projects the possible outcomes of this experiment according to parameters that are adjusted through political decisions. The public cannot be expected to grasp all the details of climate science. Yet public acceptance of its key findings is essential to support climate policy. Recognition of the consensus among experts is a gateway to accepting the reality of climate change. How do we know there is a scientific consensus and how do we communicate that fact to the public?


At the End of Chemistry

Dr. Donald Bergstrom
Professor Emeritus
Department of Medical Chemistry and Molecular Pharmacology,
Purdue University, West Lafayette, Indiana
Date: October 16, 2015
Place: Chem-Sci Room 101
Time: 3:00 pm

Abstract
For more than a half century I have designed and created new molecules. My research has been shaped within the contexts of culture, time, and place, at times responding to the work of others, but always attempting to ride the wave front of science. “At the End of Chemistry” follows the trajectory of my research from rocket design in the 1950’s to nanomaterials in the 21st century. It is both report and inquiry about the nature of research.

Biography
Don Bergstrom has held faculty positions at Purdue University (1989-2011), the University of North Dakota, and the University of California, Davis. He holds degrees in chemistry from the University of Washington (BS, 1965) and the University of California, Berkeley (PhD, 1970). From the early 1970s the work in his laboratory focused on nucleic acid chemistry, particularly the synthetic chemistry and applications of nucleosides. In the 21st century his efforts expanded into areas of nanotechnology and new approaches to drug design based on concepts of molecular self-assembly. He is currently a 2nd year graduate student in the MFA program in Applied Craft + Design at the Pacific Northwest College of Art.


Atomistic Resolution Dances of Membrane Proteins by NMR

Dr. Ayyalusamy Ramamoorthy, Professor
Biophysics and Department of Chemistry, University of Michigan
Date: September 25, 2015
Place: Chem-Sci Room 101
Time: 3:00 pm


Abstract

Membrane proteins are an exciting class of biomacromolecules and play important roles in a variety of biological processes that are directly linked to major diseases including cancer, aging-related diseases, and infectious diseases. A complete understanding of their function can only be accomplished using high-resolution structures and dynamics. In spite of recent developments in structural biology, membrane proteins continue to pose tremendous challenges to most biophysical techniques. A major area of research in my group is focused on the development of NMR techniques to study the dynamic structures of membrane bound proteins such as cytochrome b5, cytochrome P450 and cytochrome P450-reductase. In my talk, I will present strategies to study the structure and dynamics of these challenging systems and also on the electron transfer mechanism that enables the enzymatic function of P450. Atomic-level resolution NMR structures of amyloidogenic proteins revealing the misfolding pathway and early intermediates that play key roles in amyloid toxicity will also be presented.
References:
J. Biol. Chem. (2015) 290:12705-18; 290: 4843-55; 288:22080-95.
Chem. Soc. Rev. (2014) 43:6692-6700; J. Phys. Chem. Lett. (2014) 5:1864.

Biography

Dr. Ayyalusamy Ramamoorthy is Professor of Biophysics and Chemistry at University of Michigan, where he has been since 1996. He has applied NMR spectroscopy and other biophysical techniques to investigate high-resolution structure, dynamics, and functional properties of membrane proteins, amyloid proteins/peptides, and antimicrobial peptides. He has published more than 250 peer-reviewed papers in leading high impact journals like Science, PNAS, JACS, J. Biol. Chem., and Angew. Chem. Eng. Intl., written several review articles, edited 2 books on NMR spectroscopy, brought out several special issues as a guest editor, and organized several conferences related to NMR spectroscopy. He is a member of editorial boards of J. Biol. Chem., Plos One, Scientific Reports, Peer J, Biochimica Biophysica Acta, Journal of Magnetic Resonance, Chemistry and Physics of Lipids, Solid State Nuclear Magnetic Resonance Spectroscopy, and Magnetic Resonance in Chemistry. He has been a PI or co-PI on several NIH (and other) sponsored projects.
For more information visit http://rams.biop.lsa.umich.edu/


Engineering Bimetallic Nanostructures as Peroxidase Mimics for Disease Diagnosis

Dr. Xiaohu Xia
Assistant Professor
Department of Chemistry, Michigan Tech
September 18, 2015
Chem-Sci Room 101 3:00pm

Abstract
Peroxidase mimics (or artificial peroxidase) with dimensions at the nanoscale have received great interest as emerging artificial enzymes for biomedicine and environmental protection. While a variety of peroxidase mimics have been actively developed since 2007, limited progress has been made toward improving their catalytic efficiency. In our recent work (ACS Nano, 2015, in press, DOI: 10.1021/acsnano.5b03525), we reported a novel type of peroxidase mimic with record high efficiency. Our peroxidase mimic was engineered by depositing Ir atoms as ultrathin skins (a few atomic layers) on Pd nanocubes (i.e., Pd-Ir cubes). The Pd-Ir cubes exhibited significantly enhanced efficiency that is over 400-fold higher than that of natural peroxidase. In this talk, I will introduce the rational design, experimental synthesis, and mechanistic understanding of such a new peroxidase mimic. At the end, using human prostate specific antigen as a model example, I will highlight the application of our peroxidase mimic in ultrasensitive detection of disease biomarkers.


ON THE PROTECTIVE PROPERTIES OF GLYCINE BASED OSMOLYTES IN A THIOL REDUCING ENVIRONMENT

Michigan Technological University
Department of Chemistry
John Hausman
Advisor: Dr. Ashutosh Tiwari
Master’s Defense
Monday August 10, 2015
9:30 am, Chem-Sci 101

ON THE PROTECTIVE PROPERTIES OF GLYCINE BASED OSMOLYTES IN A THIOL REDUCING ENVIRONMENT

The protective properties of osmolytes have been studied intently for decades. Originally used to aid in the crystallization of proteins in x-ray diffraction studies, these cosolvents have been shown to reverse protein denaturation and aggregation. Osmolytes aid extremophiles in surviving harsh environments by preferentially excluding themselves from the surface of the protein, thus directing water molecules to the protein’s surface. Their use is increasing and affects the everyday consumer as these osmolytes are naturally found in many health foods and also in many daily use products such as shampoo. Consumers also supplement their diets with thiol-based antioxidants such as glutathione as part of healthier life style. However, thiol-based antioxidants in high concentration have been known to cause un-intended health issues that relate to its disulfide reducing property. The disulfide-reducing agent can cleave the proteins’ disulfide-bonds and promote misfolding and aggregation. In this thesis, we investigated the influence of commonly consumed glycine-based osmolytes on providing stability to proteins against a disulfide-reducing agent. We chose glycine, sarcosine (N-methyl glycine), di-methyl glycine (DMG), and betaine (N,N,N-trimethylglycine) with increasing number of methyl groups. An added benefit to studying this class of osmolytes is to also investigate the impact N-methyl substitution has on the osmolytes’ protective properties. We studied the effect of these osmolytes on protein aggregation using spectroscopic techniques such as UV-visible absorbance, intrinsic fluorescence and extrinsic fluorescence measurements. In addition, we carried out non-reducing SDS-PAGE to check for higher order aggregates and characterized morphology of these aggregates using scanning electron microscopy. Overall, our results show that of all the osmolytes used, glycine was the best stabilizer followed by sarcosine. Betaine and dimethylglycine did not provide effective protection against disulfide-reducing influence.


Gold Nanorod-based Theranostics for Specific Cancer Imaging and Therapy

Jianheng Bi
Original Research Proposal
Michigan Technological University
Department of Chemistry
Advisor- Dr. Haiying Liu
Tuesday August 4, 2015
9:00 am
Chem-Sci 101

ABSTRACT
This proposal describes the preparation, characterization and application of gold nanorod-based theranostics for specific cancer imaging and therapy. Cancer theranostics will be constructed by modifying the gold nanorods with near-infrared dyes and cancer-imaging peptides via silica layers and poly(ethylene glycol) tethered spacers. The thickness of the silica layers will be carefully controlled to significantly enhance the fluorescence intensity of near-infrared dyes via a surface plasma of gold nanrods while specific targeting and imaging will be achieved through strong specific multivalent interactions of cancer-homing peptide residues with cancer cells and tissues. Once specific targeting to cancer cells or tissues are achieved, thermotherapy and photodynamic therapy will be conducted to kill cancer cells and tissues via thermal heat from gold nanorods and singlet oxygen generated by photodynamic agent under near-infrared pulse laser.


Title: Soil Organic Matter Matters: Why is there so much carbon underground?

Chemistry Seminar
Dr. Katherine Heckman, Research Biologist
USDA Forest Service, Northern Research Station

Friday July 24, 2015
Chem Sci Room 101
3:00 pm

Title: Soil Organic Matter Matters: Why is there so much carbon underground?
Abstract:

Soils contain roughly twice as much carbon as the atmosphere, and 1.5 times as much as the atmosphere and aboveground vegetation combined. Yet the mechanisms regulating the stability of this massive carbon pool remain the largest uncertainty in terrestrial carbon models. To provide context, a brief review of the soil carbon cycle and mechanisms of soil carbon stabilization will be given, followed by the results of a recent investigation into how mineral crystallinity influences soil carbon stability.

Bio:
Kate Heckman earned her PhD in Soil Science at the University of Arizona in 2010, and since then has been working for the USDA Forest Service. In addition to doing basic research involving soil, Kate also runs the Radiocarbon Collaborative, a research initiative focused on making radiocarbon analyses more accessible to earth systems researchers. Kate will be moving up to Houghton this fall where she will continue her research in the Forestry Sciences Laboratory at Michigan Tech.


Xu Xiang
PhD Defense
Doctoral Candidate, Department of Chemistry
Advisor: Dr. Patrica Heiden

Friday July 24, 2015
Memorial Union Ballroom A-1
9:00 a.m.

Novel Drug Delivery Systems: Thermo-responsive drug delivery designs and Multi-drug delivery scaffold designs

Abstract:
This research has three parts: two deal with novel medical devices for drug delivery, and one looks at properties of fish scales as an abundant waste resource that can be modified to have value in medical and other areas. This presentation discusses two novel drug delivery designs, including their synthesis and characterization. These nanoparticle devices address two current challenges in drug delivery. The first is designing a drug-carrier to more efficiently deliver toxic (e.g. chemotherapy) drugs, which harm all cells. So non-specific delivery of the drug is wasteful and harmful to the patient. Knowledge gained from a fundamental study of the effects of polymer architecture (linear amphiphilic diblock and triblock copolymers and star copolymers) and end group polarity, on thermally triggered drug delivery led to selecting two diblock copolymers to assemble into novel gold-core hybrid nanoparticles. These nanoparticles were tested for their ability to reduce low temperature release and efficiently release the drug at a triggered temperature. The second drug delivery system extended the capabilities of a new type of tissue support device (a scaffold) by showing that the system can independently control the simultaneous release of different drugs, and that the spatial distribution of these drugs within the device, called a “nanoparticle fiber”, can be controlled. Three different model drugs were assembled and their release proven, within the nanoparticle fiber. This work succeeded in yielding a novel, flexible, and robust system of assembled fibers of nanoparticles that could independently control the release of multiple drugs.


Total Synthesis of Belizentrin

Total Synthesis of Belizentrin

Shahien Shahsavari
Original Research Proposal
Michigan Technological University
Department of Chemistry

Advisor- Dr. Shiyue Fang
Monday July 6, 2015
10:00 am
Chem-Sci 101

Abstract

Marine organisms are known to produce some of the most bioactive secondary metabolites found in nature. Currently, many of these marine-derived molecules are used as “first-in-class” drugs in the market. This proposal describes the total synthesis of belizentrin, a novel polyketide-derived macrocycle isolated from the marine dinoflagellate Prorocentrum belizeanum. Belizentrin has already demonstrated effective changes in neuronal survival assays in vitro at nanomolar concentrations. Additionally, its highly bioactive properties and structural similarities with other known immunosuppressant compounds make it a valuable target for medical research. However, since the extraction yield is minimal, it is essential to produce this compound in larger quantities from readily available starting materials for a complete investigation of its biological activities. The overall synthetic strategy involves a convergent late-stage coupling of three major fragments. The key features of the synthesis include iterative asymmetric allylic substitutions, titanium-catalyzed asymmetric epoxidation of terminal olefins, and the Yamaguchi macrolactonization to form the macrocyclic core of the molecule.


T Synthesis of Isobractatin and Neobractatin

Shanshan Hou
Original Research Proposal
Michigan Technological University
Department of Chemistry
Advisor- Dr. Lanrong Bi
Tuesday April 21, 2015
9:00 am
Chem-Sci 106

T Synthesis of Isobractatin and Neobractatin

Abstract
The new Garcinia derivatives, neobractatin and isobractatin, will be synthesized. These compounds are caged-prenylxanthones which are isolated from Chinese native Garcinia bracteata. They displayed strong inhibition of cancer cells, which could significantly induce cell apoptosis and inhibit autophagy. However, the compounds which are extracted from the Chinese native Garcinia species have very low yield. Total synthesis of these derivatives will provide adequate quantities for biological studies. In addition, the new synthetic methodologies could not only produce the target compounds but also give rise to their isomers which could be potential anti-tumor candidates and used for future research.