[Consumption of the triazine herbicide atrazine by laccase and laccase-free variants of the soil fungus Mycelia sterilia INBI-2-26].
Asporogenic fungus Mycelia sterilia INBI 2-26 isolated from tropical soils with high residual dioxin content (as a result of Agent Orange defoliant treatment during the Vietnamese-American war) and capable of atrazine decomposition was treated to obtain protoplasts. This technique resulted in isolation of laccase-positive and laccase-negative clones. Atrazine consumption by liquid surface cultures of Mycelia sterilia INBI 2-26 was monitored by using enzyme immune assay and reversed phase HPLC. Atrazine (20 micrograms/l) stimulated fungal growth. Laccase-positive clone consumed up to 80% of atrazine within four weeks. However, no correlation of atrazine consumption and laccase activity in the culture medium was observed. Moreover, the laccase-negative clone was also capable of consuming at least 60-70% of atrazine within three weeks. Surprisingly, in the corresponding control set (cultivation of laccase-negative clone without atrazine) an unidentified metabolite having a retention time and UV-spectrum similar to those of atrazine was also found. It was concluded that the presence of laccase was not a crucial factor in atrazine consumption by this fungus.
Vasil'chenko
L G
LG
Bach Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 119071 Russia.
Khromonygina
V V
VV
Koroleva
O V
OV
Landesman
E O
EO
Gaponenko
V V
VV
Kovaleva
T A
TA
Kozlov
Iu P
IuP
Rabinovich
M L
ML
D001280:Atrazine / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D005658:Fungi / Q000201:enzymology / Q000378:metabolism*; D006540:Herbicides / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D042845:Laccase; D010088:Oxidoreductases / Q000378:metabolism*
D003470:Culture Media; D006540:Herbicides; D010088:Oxidoreductases; D042845:Laccase; D001280:Atrazine