Dr.M.K.Chattopadhyay,
M.Pharm, Ph.D from Jadavpur University, Kolkata
Summary of the lecture delivered in the Golden Jubilee of the Department of Pharmaceutical Technology, Jadavpur University, Kolkata on 23 February 2013
During the past few decades, the widespread emergence of antibiotic-resistant strains of bacteria and other microorganisms has posed a serious challenge to the prospect of chemotherapy. Hence discovery of new antibiotics is the need of the hour. The task is beset with a number of problems and fewer and fewer antibiotics were commercialized during the recent past compared to what we got during the Golden Era of antibiotics (mid 1940s to mid 1970s). In order to contain the looming crisis, a number of approaches have been adopted. Pharmaceutical companies are tapping new sources (samples obtained from tropical rain forests, myxobacteria, marine bacteria, extremophilic bacteria) for novel antibiotics. Attempts are made to develop antimicrobials targeted against bacterial molecules, which were not targeted earlier (e.g, bacteria DNA polymerase III, the cell division protein FtsZ, fibronecting binding proteins). Genes indispensable for survival of the pathogens are being shortlisted in search of new targets. In another strategy, molecular techniques are being used to clone the antibiotic biosynthetic gene cluster of a strain into a different strain, ultimately to get a hybrid molecule with antibiotic activity. In another approach called directed evolution, libraries are developed with randomly mixed and matched gene clusters obtained from different antibiotic producer strains. These libraries are transformed into protoplasts and recombinants are screened for improved spectrum of antibiotic activity. Large number of new compounds synthesized on a solid support, are screened for activity in another technique called combinatorial chemistry. These strategies are expected to generate new compounds with novel antimicrobial activities.
Present address: Scientist, Centre for Cellular and Molecular Biology (CSIR), Hyderabad 500 007, A.P, Tel: 040-27192545, E-mail: mkc@ccmb.res.in