Saroj K. Pramanik

Toxicity of Polychlorobiphenyls and its Bioremediation

Abstract PCBs are chlorinated aromatic compounds known to have toxic effects on humans and animals. They are well known mutagens and carcinogens and are known to affect almost all systems of the body. They have neurotoxic effects especially on infants and children and may have persisting effects in adults as well. The mechanism of action of neurotoxicity is probably through disruption of Ca2+ homeostasis. PCBs are known to cause hepatocarcinoma through genotoxicity and through receptor mediated deregulation of apoptosis. They have deleterious effects on the endocrine system because of their structural similarity with the steroid hormones especially estrogen. They also act as goitrogens and increase the thyroid stimulating hormone level. Polychlorobiphenyls also down-regulate the immune system probably through apoptotic pathways. As they cross placenta neurotoxic, immunomodulatory and other developmental effects are seen on the new born. Infants are also affected by PCB secreted through breast milk. PCBs are also found to cause atherosclerosis through oxidative stress and endothelial cell dysfunction. Available methods of PCB removal through incineration may lead to formation of more toxic dioxin like compounds. Partial metabolites of PCB are also equally harmful. Complete biodegradation may be the only way to clean up the PCB contamination which is persistent in the environment even after being banned from USA since 1977. Many bacteria and fungus which can degrade PCB have been identified. Since the prevalent hypothesis of degradation, first by dechlorination by anaerobic organisms followed by ring cleavage by aerobic organism has inherent difficulties, a novel finding of reductive dechlorination by the white rot fungus may help to accelerate PCB biodegradation.

Quantum dots: a promising tool in molecular biology

Quantum dot is a spatial semiconductor of periodic groups of II-VI, III-V, or IV-VI materials, which generates optically stable fluorophores upon excitations at various wavelengths (from UV-IR). To date, quantum dot technologies are used in various fields and the use in molecular biology has increased dramatically over the past years. In this review article, we would discuss the potential uses of this versatile nano crystal. Quantum dot technology is also used in cell labelling, bio-sensing, in-vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. We would also discuss toxicity issues surrounding this nano crystal and speculate about the future uses of quantum dot in large areas of biomedical sciences.

Abstract 4485: Anticancer properties of novel rhenium compounds against human cancer cell lines.

Cisplatin, carboplatin, oxaliplatin, and related metallodrugs are extensively being used in the treatment of a variety of cancers. Unfortunately these drugs are highly toxic and tumor becomes drug-resistance. These circumstances have led researchers to look for new cytotoxic agents that may exhibit less toxicity and devoid of drug resistance. It is believed that cisplatin and related drugs directly bind to genomic DNA through purine bases. Synthesis of new metallodrugs which does not follow the above mechanism of action might yield better drugs with less toxicity and devoid of drug resistance. Recently we have demonstrated that several anticancer rhenium compounds do not directly bind to DNA. We have synthesized numerous rhenium pentylcarbonato and acetylsalicylato complexes which include (CO)3(2,2’-Bipyridyl)ReOC(O)OC5H11 (PC-1), (CO)3(1,10-Phenanthroline)ReOC(O)OC5H11 (PC-2), (CO)3(5-Methyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)OC5H11 (PC-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)Re ReOC(O)OC5H11 (PC-7), (CO)3(2,2’-Bipyridyl)ReOC(O)C6H4·C(O)OCH3 (ASP-1), (CO)3(1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3, (ASP-2), (CO)3(5-Methyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-3), (CO)3(2,9-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-4), (CO)3(5,6-Dimethyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-5), (CO)3(4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-6), (CO)3(2,9-Dimethyl-4,7-Diphenyl-1,10-Phenanthroline)ReOC(O)C6H4·C(O)OCH3 (ASP-7). The anticancer properties of the compounds were evaluated using human prostate, alveolar lung, brain, colon, and leukemia cancer cell lines and normal bone marrow cell lines. The results of this study demonstrate that these complexes have significant anticancer properties. Therefore, these complexes can potentially find applications in the treatment of these cancers. Acknowledgment. The work at MSU was partially supported by grants from the National Institutes of Health (Grant No. G11HD038439) and Nuclear Regulatory Commission (Grant No. NRC-HQ-12-G-27-0086). The work at ECSU-UNC was partially supported by grant from the Department of Energy (TMCF/DOE grant). Citation Format: Hirendra N. Banerjee, Deidre Vaughan, Jewe Medley, Gwyn Hyman, Christopher Krauss, Carl Parson, Santosh Mandal, Pola Olczak, Michael Mbagu, Divine Kebulu, Saroj Pramanik, Fazlul Sarkar. Anticancer properties of novel rhenium compounds against human cancer cell lines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4485. doi:10.1158/1538-7445.AM2013-4485

Mathematical models for Enterococcus faecalis recovery after microwave water disinfection.

Microwave water disinfection is a rapid purification technique which can give billions of people access to clean drinking water. However, better understanding of bacterial recovery after microwave heating over time is necessary to determine parameters such as delayed bacterial growth rates and maximum bacterial yields. Mathematical models for Enterococcus faecalis recovery after microwave treatment in optimum growth conditions were developed for times up to 5 minutes using an optical absorbance method. Microwave times below 3 minutes (2,450 MHz, 130W) showed that bacterial recovery maintained a time-dependent sigmoidal form which included a maximum value. At microwave times greater than three minutes, bacterial recovery, with a time-dependent exponential form, significantly decreased and did not reach the maximum value within the interval of observance (0-8 hours). No bacterial growth was found after 6 minutes of microwave treatment. The prepared mathematical models were produced by transforming the given variables to the logistic or exponential functions. We found that time-dependent maximum growth rates and lag times could be approximated with second order polynomial functions. The determined models can be used as a template to illustrate bacterial survival during water purification using microwave irradiation, in both commercial and industrial processes.