Abstract: The invention relates to a method for producing stable, surface-expressed polypeptides from recombinant gram-negative bacterial cell hosts. A tripartite chimetic gene and its related recombinant vector include separate DNA sequences for directing or targeting and translocating a desired gene product from a cell periplasm to the external cell surface. A wide range of polypeptides may be efficiently surface expressed, including .beta.-lactamase and alkaline phosphatase. Full enzyme activity is maintained and the proteins remain anchored to the bacterial outer membrane surface.

Abstract: A valve is disclosed herein having an open-ended passageway with a movable gate inbetween its opposite ends for selectively opening and closing the passageway. The opposite valve ends defining the passageway include a threaded fitting or cap carried on a valve body defining a tapered gland occupied by a frustro-conical resilient seal cooperating with the gland to seal between a conduit and the valve body. The valve body is adapted for installation in a situation joining opposing ends of separated conduit or pipes.