FIGURE 1 Extraction and preparation of water stress protein. (A) Physical extraction of water stress protein using pyruvate precipitation method. WSP is located near the 45 kD of protein marker. 1: WSP of the “ Nostoc commune ” Vauch after ammonium sulfate treatment. 2: crude extract. (B) Recombinant water stress protein created by genetic engineering. WSP is located near the 40 kD of protein marker detected by SDS-PAGE. 3: bacteriophage after ultrasonication lysis treatment. 4: WSP after af fi nity puri fi cation. (C) Puri fi ed water stress protein through nickel column puri fi cation (nickel puri fi ed), and anion exchange chromatography (anion exchange). 4: WSP after af fi nity puri fi