Figure 4

Chemical compositions of the filaments by. A. FTIR absorbance spectra of the straw cells (CACO2 and bovine liver), along with proteins (serum, BSA), polysaccharide (blue dextran) controls indicate the straw cells are dominated by bands characteristic of polysaccharide. B. SDS/PAGE of the straw cells. Collapsed filaments were dissolved in 1 × SDS loading dye and separated on 8% acrylamide gel. Approximately 1% of loading material was stained positive with Coomasia blue as proteins. Their molecular weights are approximately 50 KD. The In-gel tryptic digestion and de novo peptide sequencing identified band 1 as BSA, which has been reduced by a factor of 5,000 from the starting medium having 10% fetal bovine serum. Band 2 and 3, enriched from straw cells, are likely to be acidic and glycosylated proteins, per their response to Coomasia blue.