The invention provides isolated PR1-C10 nucleic acids and their encoded polypeptides. The seat rail assembly includes a lower rail which is fastened to a floor panel of a vehicle body, and an upper rail to which the seat is secured. Accordingly, a disposable container having an excellent hardness, elasticity and compact texture can be manufactured by using the biodegradable materials. The extruded starch product thus formed may be used in connection with a number of film-forming, coating, and other applications.