The New Age In Microbiology

"Microbiology has always been at the forefront of science," says Mitch Singer, assistant professor of microbiology. "If you look at the major technological advances in biology within the past three decades, many have been made through work in microbes."

Singer is right. One of the most significant of these advances, recombinant DNA technology, was developed in the early 1970s using the well-studied intestinal bacterium Escherichia coli. Used to create new combinations of unrelated genes in the laboratory, recombinant DNA techniques have made it possible to find and manipulate genes from a variety of organisms, including humans. Another revolutionary technique, polymerase chain reaction, or PCR, was developed using the heat-stable bacterium Thermus aquaticus. First described in 1985, PCR has become a widely used method to amplify the number of copies of a specific sequence of DNA to produce enough DNA to be adequately studied.

Left: Mitch Singer.

The advent of these techniques and others made it possible to expand studies of biological processes into systems more directly relevant to human biology, without sole reliance on microbes as models of more complex systems, says Singer. "Now, for example, we could use molecular tools to study a disease process in cultured mammalian cells." As a result, the scientific community experienced a shift in focus from microbiology toward areas such as cell and developmental biology during the 1970s and '80s, he says.

Ironically, the same technological advances that shifted the focus away from microbiology are playing a role in its revival. "We've come full circle. We're now going back and using molecular and genomic techniques to reexamine aspects of microbiology that we couldn't examine before," says Singer. "The ability to isolate, identify, and characterize microbes has become explosive."

Professor Doug Nelson says one of the astounding things to come out in microbiology in recent years is the tremendous diversity of bacteria on Earth. "What's in culture may represent a tenth or a hundredth of a percent of everything that's out there," he notes.

Right: Doug Nelson(Photo: Rich Pebroncelli, S&S/Prentice Hall College).

Nelson says the field is currently in a phase in which scientists are using molecular techniques, including recombinant DNA and PCR, to collect lots of data about uncultured organisms, and to determine their evolutionary relationship. He thinks the next step will involve the hard work of getting uncultured organisms that are prevalent in the environment into culture, and to learn something about their physiological properties.

"It's essential that we develop a baseline understanding of microbial populations that are dominant in the biosphere," he says. "We need to know how they are adapted to their environment, and what happens to them if they are perturbed." A specialist in the ecology of microbes living in deep-sea hydrothermal vents, Nelson is particularly concerned about the marine environment. "If people are going to continue to dump wastes into the ocean, we need to know what the capacity is for the system to catabolize the waste," he adds.

Mitch Singer has also observed a push to study bacteria as members of natural populations. "Microbes do not exist as a single entity like we've studied in the lab for the past 50 years," he remarks. Singer is well aware of the social nature of bacteriahe is an expert on the biology of Myxococcus xanthus, whose social behavior has been studied for more than 100 years. "We now know that many types of bacteria communicate with one another by producing pheromone-like substances," he says.

Microbiologist Michele Igo has noticed a growing appreciation within the scientific community of the value of using bacteria such as E. coli to study the dynamic nature of biological events. "People are just beginning to look at how things like cellular communication pathways work at real rates and real timeand they're doing it in E. coli," says the associate professor. "In mammalian systems, there is still a lot of work to be done simply identifying the components. In microbial systems, we've already identified many of the key components and can now focus on how they interact."

Right: Michele Igo

In her own research, Igo uses E. coli as a model to study how organisms sense and respond to environmental cues. Specifically, she studies a communication pathway known as a two-component regulatory system. "This type of system appears to be a common strategy used by cells to process environmental information," she explains.

Interest in two-component regulatory systems has grown in recent years. They are used by many pathogenic microbes to adapt to microenvironments in the host and undergo a successful pathogenic cycle. Two-component systems have been found to control virulence by Bordetella pertussis, the cause of whooping cough, Staphylococcus aureus, implicated in toxic shock syndrome, and Salmonella typhimurium, a culprit in gastroenteritis.

Igo attributes the increased visibility of the field of microbiology in part to growing publicity about medical problems associated with bacteria. "There have been reports in the media about bacterial contamination of food and water, communicable diseases such as tuberculosis, and antibiotic-resistant bacteria," she says. "These problems have certainly prompted people to think more about the field."

MICROBIOLOGISTS WANTED

The outlook is bright for microbiology graduates seeking a career in biotechnology. As companies in the industry become increasingly successful in getting products to market, their manufacturing capabilities must grow and so must their work force. Since many biotechnology products are produced in microbial systems, formal studies in microbiology are particularly relevant to the work.

"Some companies are currently recruiting large numbers of new people, especially in manufacturing, quality control, and production," says Mary Beth Mountan, a health and biological sciences coordinator in the campus's Internship and Career Center. Among these are Genentech, which plans to hire 350 new employees to staff its new manufacturing plant in Vacaville, CA, and Amgen of Thousand Oaks, CA, which plans to add 1,000 new employees. The majority of these positions will be at the bachelor's degree level.

"These are well-paying positions, starting in the low thirties," offers Mountan. "You're also likely to make more money in manufacturing with a bachelor's degree. You can enter a management track, which leads to higher salaries. And production often goes 24 hours a day, so there are shift differentials in pay."

The outlook is especially bright for UC Davis graduates. According to Mountan, both Genentech and Amgen favor the campus as a recruitment site. In fact, the companies are so interested in UC Davis students, they've each hired an undergraduate to work on the campus as an ambassador who interacts with students to increase the company's visibility.

"We're particularly interested in life sciences students who have hands-on work experience, and who are well-rounded, doing volunteer or philanthropic work in the community," says Marnie Moody from Genentech's Employment Department. "It's never hard to find these types of students at UC Davis."

The Health and Biological Sciences Program in the UC Davis Internship and Career Center is a national leader in providing professional-caliber internships to students in the sciences, placing some 3,000 students in internships each year. Information about science careers, employers, and job openings is available free of charge to UC Davis students and alumni at 203 South Hall (phone: 916/752-1823) and on-line at http://icc.ucdavis.edu/areas/hbs/hbs1.htm, the program's World Wide Web site.