Consequently, we switched to
comparing melanized and non-melanized acapsular cells but again
failed to assign melanin spectral features in the diffraction
spectrum. Our inability to detect a clear melanin signature from
the comparison of melanized and non-melanized cells is perhaps
not surprising if one considers that the amount of melanin per cell
is likely to be only a small percentage of the total mass [10]. Of
interest, we noted the absence of the broad monotonic band in
acapsular cells and proceeded to investigate whether this signal
was originating from the polysaccharide capsule. Analysis of
isolated polysaccharide confirmed that it produced a diffraction
spectrum dominated by a broad monotonic band which was
intriguingly similar to that of melanin.