Abstract: The present invention provides methods for screening for compounds that modulate, e.g. inhibit, the activity of topoisomerases such as DNA gyrase, comprising providing cells expressing topoisomerase and containing a promoter sensitive to changes in DNA topology having a reporter gene operatively linked thereto, and measuring the expression of said reporter gene in the presence and in the absence of a test compound. Compounds that modulate the activity of topoisomerase can be identified by virtue of an alteration in reporter gene expression.

Abstract: A locking mechanism and method are provided for use in any photographic system which uses film cartridges. One embodiment includes a drive lever and an actuator which prevent movement of a slider door release, thus preventing unlocking of a film door when a film spool is improperly parked within a cartridge. Proper parking is determined by the position of a drive spindle, which operatively engages the film spool. In another embodiment, an actuator contacts a drive spindle and selectively engages a light lock driver. When the light lock driver is not engaged, the slider door release is moveable to unlock the film door. When the light lock driver is engaged, the slider door release is not moveable to unlock the film door. A user controlled mechanism may be included to properly park a film spool in the event that the photographic system improperly parks the film spool. An electro-mechanical switch may be included for properly parking the film spool.

Abstract: A camera is provided that includes a door which is selectively movable between an open position and a closed position and a release which is movable between a home position and an away position for selectively retaining said door in said closed position. Door position, release position and film sensors each have at least two states for determining the position of the door and release and for determining presence of film in the camera. The sensors are disposed within an electric circuit for allowing operation of the camera as a function of the states of the sensors.