The present invention is directed to novel polypeptides and to nucleic acid molecules encoding those polypeptides. The packaging can be folded into overlapping flaps and wings which are folded and interlocked to define a generally trapezoidal packaging which can receive a variety of different pot sizes and types. Kits suitable for such a screening method are also disclosed. In addition, the feedback circuit comprises single feedback loop having stacked photocouplers, one controlling the AC-to-DC converter and the other controlling the DC-to-DC booster converter, to select the overall DC output voltage.