A super-flexible robot snake, a vaccine for diabetes and a system to prevent surgical sponges from being left inside patients were among the highlights of a Pittsburgh Life Sciences Greenhouse tour yesterday for Mayor Luke Ravenstahl and County Executive Don Onorato.

The tour was given to tout the Hazelwood-based nonprofit's success in assisting nearly 300 companies in the early stages of their development since the Greenhouse's founding in 2001.

Standing on a fifth-floor terrace overlooking the Monongahela River valley, president and CEO John W. Manzetti pointed out the region was once home to some 200,000 people employed by steel mills that lined the river's banks. "Now we employ about 200,000 high-tech folks," he said, about half in the life sciences.

City and county officials plan to highlight that next month when visitors arrive for the G-20 international summit. "We will steer them to places like this" to illustrate Pittsburgh's transformation, said Mr. Ravenstahl.

Mr. Onorato said Pittsburgh is a model for other places. "If you want to see what the future of an old industrial site could like, we have it right here."

The tour included visits with CardioRobotics, creators of the robot snake designed to enter the body through a quarter-inch incision so that surgery can be performed using tools attached to it; Diamyd, developers of the diabetes vaccine undergoing testing; and Clear Count Medical Solutions, the company with the surgical sponge tracking system.

Thirteen companies share the Greenhouse incubator space but its services to startups range from consultation to mentoring to capital investment. Spokeswoman Lynn M. Brusco said on an ongoing basis, the nonprofit has about 200 companies under review.