Bacillus cereus58 (Bc58) is a UV-resistant
wild type strain that has an ability to produce a sorrel pigment
induced by L-tyrosine. The Fourier-transform infrared
(FT-IR) spectra and chemical tests of its pigment are similar
to that of the standard melanin (Sigma). A bioassay shows that
the LC
50
of a Bacillus thuringiensis (Bt) formulation added
with the melanin of Bc58 and exposed to UV for 5 h is
16.1 µg/m1, which is similar to that of the Bt formulation
without UV treatment, however, it is almost double that of the
Bt formulation exposed to UV without the melanin of Bc58.
The result of SDS-PAGE indicates that the melanin of Bc58
can protect the insecticidal crystal proteins from degradation.
This suggests that it is an excellent UV protective agent for
the insecticidal crystal proteins of the Bt formulation.
peptone-yeast extract agar and synthetic tyrosine-agar. They also show the positive reaction to L-tyrosine or L-dopa substrates. The pigment has been referred to be as merely as dark brown water-soluble pigment, as melanoid or melanin. The different carbon and nitrogen sources which influence
the pigment production in the Streptomyces isolates were also investigated, and the carotenoid content
in the pigment was analyzed. The melanin formation in the Streptomyces species is the key feature for
the classification of the Stretomyces group.