Department Seminar Speakers - 2009
- Dr. Mihaela Bojin (QCC, CUNY)
- November 20, 2009
- Title: "What Happens To Amino Acids When the pH Changes?"
- Abstract: Using computational chemistry we explore different conformations of a series of amino acids using density functional (DFT) methods. Amino acids intra- and intermolecular interactions are significantly influenced by surrounding residues and the pH of their environments. Hydrogen bonds, in particular, control folding in secondary and tertiary structures in proteins and significantly affect enzymatic activity. By employing the B3LYP/6-31+G(d,p) method we determine the major conformers of aspartic acid (Asp), asparagine (Asn), serine (Ser) and threonine (Thr) in their neutral (no charges), zwitterionic, acidic (protonated), and basic (deprotonated) forms, in gaseous and aqueous media. We find that changes in acidity critically influence and limit hydrogen bonding patterns, and thus the stability of the resulting conformers.
- Dr. Gloria Proni (John Jay College of Criminal Justice)
- October 16, 2009
- Title: "1. Probing Chirality of Diamines by CD-sensitive Dimeric Zn-porphyrin Tweezers
2. Index of Freshness Analysis of Tuna Sushi and Sashimi Gathered from New York City Markets"
- Abstract: 1. For more than a decade, dimeric metalloporphyrin hosts, known as tweezers, have been successfully applied as chirality probes for determination of absolute configuration of a wide variety of chiral synthetic compounds and natural products. The tweezer methodology relies on a stereo-differentiating host/guest complexation between bis-porphyrin tweezer and chiral substrate containing two sites of coordination. This results in an intense exciton-split CD signal, which is diagnostic for the absolute configuration of the guest. In this presentation recent advances in the technique will be discussed, in particular its application to several classes of substrates and important natural compounds.
2. News articles have shown that the quality and safety of raw fish sold in New York City is questionable. Because of the potential dangers associated with the consumption of raw fish, the freshness of the raw tuna in the form of sushi and sashimi from 12 restaurants in New York metropolitan area was investigated. The determination of the index of freshness (K coefficient) and consequently the biochemical age of several fish samples was achieved by using a technique that extracts and quantifies the products of the ATP breakdown during fish aging. In this presentation data regarding the biochemical ages of the samples and their index of freshness are presented.
- Dr. Spiro Alexandratos (Hunter College, CUNY)
- September 25, 2009
- Title: "The Earth in Crisis: Pollution of Water in the Biosphere – Current Status and Steps Towards Renewal"
- Abstract: Groundwater is an essential resource yet it is being contaminated with metals and molecules that are highly toxic to plant and animal life. Metals (nickel, cobalt, chromium, copper, lead, cadmium, etc.) may be present at a level of 1 part per million – a level that seems low but is high enough to be toxic. As one of many examples, a site in the state of North Carolina, declared toxic by the US Environmental Protection Agency, is the former location of a battery recycling operation where lead from 95000 cubic meters of contaminated soil has migrated into the aquifer to a depth of 18 meters and now contaminates 320000 cubic meters of groundwater. Compounds that can contaminate groundwater include fuel components, pesticides, and steroids; this is especially serious because some alter the reproductive and endocrine systems of wildlife and humans by acting with estrogen, androgen, and thyroid hormone receptors. Current approaches to the removal of toxic metals from groundwater will be described, including contributions from our laboratory that have led to the development of three polymer-supported reagents: one for the removal of arsenic, one for the removal of radioactive metals, and one for the removal of perchlorate.
- Dr. Sanjai Kumar (Queens Collge, CUNY)
- April 3, 2009
- Title: "Understanding the Role of Protein Phosphorylation in Cell Siganling Using Chemical Biology Approaches"
- Abstract: Nek2 is a Ser/Thr centrosomal kinase that tightly regulates centrosome cohesion and separation so that accurate chromosome segregation is achieved during mitosis. In animal model, it has been shown that any abnormal activity of Nek2 kinase may lead to a loss of regulation in precise chromosome segregation during mitosis. In fact, Nek2 has been found to be abnormally expressed in many types of cancer cells and is a target for cancer therapy. While biochemical, proteomics and microscopic data strongly suggest that one of the main biological roles of Nek2 is to oversee the function of centrosome during the early mitosis and possibly during the entire cell cycle, a precise mechanism by which this is achieved at molecular level remains to be unraveled. We intend to develop novel chemical tools (inhibitors, substrates, and sensors) that will be used for discovering the unknown biological function of Nek2 in human biology and cancer.
- Dr. Richard Stripp (John Jay College)
- February 20, 2009
- Title: "Forensic Toxicology: The Medico-legal Aspects of Drugs and Chemicals"
- Abstract: This seminar will serve as an introduction to the basic principles of forensic toxicology. The emphasis will be on the common drugs/poisons that are encountered by the practicing forensic toxicologist and the approach to determining their medico-legal role in establishing the cause of death and disease. Topics that are explored include impairment versus intoxication and how the interpretation of drug effect is utilized in the criminal court setting. The science of ethanol and drugs of abuse, along with other important agents (sports doping drugs, therapeutic drugs, CO etc.), will be discussed as they relate to toxicology. An introduction to the basic applied methods of forensic toxicology is also presented including; biological samples, analytical schemes, and some of the special problems commonly encountered in forensic toxicology.