Selman Waksman Revisited

Rutgers Professor of Microbiology Selman Waksman won the 1952 Nobel Prize in Physiology or Medicine for the discovery of streptomycin. Working at Rutgers’ College of Agriculture, Waksman and his students spent nearly three decades analyzing soil microbes before they isolated and identified the antibiotic streptomycin in 1943, which helped combat the scourge of tuberculosis during the 20th century.

Waksman and most of his co-workers are long gone, but his legacy lives on. With the emergence of drug resistant bacteria that cause diseases, such as tuberculosis, the search for new antibiotics has become a priority. At Rutgers’ Biotechnology Center for Agriculture and the Environment, molecular biologist Gerben Zylstra leads an initiative that picks up where Waksman left off, but now employing molecular tools to streamline and accelerate laboratory processes.

The first challenge the new generation of researchers face, however, is that the discovery potential of our local soils was exhausted by Waksman’s group. Continued soil testing would only show bacteria they had already found, over and over. Thus, the search for the small number of as yet undiscovered microbes and antibiotics has become a much more challenging and labor intensive process.

But shifting the search to the other side of the world has now expanded the horizons for discovery. Through Professor Ilya Raskin’s Global Institute for BioExploration, Zylstra is working with microbial biochemist Jerry Kukor and marine microbiologist Lee Kerkhof in the central Asian republic of Kyrgyzstan. The unexplored soils in this exotic locale contain unique bacteria that the researchers hope will yield new and different chemicals with antibiotic properties.

These 21^st century researchers are still faced with the arduous task of screening the

thousands of new Asian soils and microbes in the hope of finding new antibiotic chemicals.

The Rutgers team is now employing sophisticated molecular tools, first in pre-screening the soils for the DNA of new microbes or of new ways to produce chemicals. If the sample tests positive, they isolate the bacteria that match the test results, and grow them to produce the chemicals which are then analyzed for antibiotic potential.

However, some bacteria cannot grow in the laboratory – only in their home soils – so a different approach is used, called metagenomics. This is the pursuit of genetic information in the absence of lab cultures of microbes, a field in which School of Environmental and Biological Sciences Dean Robert M. Goodman did some pioneering work.

In this cutting-edge technique, researchers isolate all of the DNA from a soil sample and clone it. The particular bacterium need not be identified. The focus is solely on finding genes that make chemicals that may have antibiotic properties.

“You can go directly after those genes and fish them out, put them in a bacterium that you can work with in the lab and, hopefully, it will start to make something that’s new and different,” Zylstra explained.