Biotransformation of explosives by Reticulitermes flavipes--associated termite Endosymbionts.
OBJECTIVE
Termites have an important role in the carbon and nitrogen cycles despite their reputation as destructive pests. With the assistance of microbial endosymbionts, termites are responsible for the conversion of complex biopolymers into simple carbon substrates. Termites also rely on endosymbionts for fixing and recycling nitrogen. As a result, we hypothesize that termite bacterial endosymbionts are a novel source of metabolic pathways for the transformation of nitrogen-rich compounds like explosives.


METHODS
Explosives transformation capability of termite (Reticulitermes flavipes)-derived endosymbionts was determined in media containing the chemical constituents nitrotriazolone (NTO) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) that comprise new insensitive explosive formulations. Media dosed with 40 µg/ml of explosive was inoculated with surface-sterilized, macerated termites. Bacterial isolates capable of explosives transformation were characterized by 16S rRNA sequencing.


RESULTS
Termite-derived enrichment cultures demonstrated degradation activity towards the explosives NTO, RDX, as well as the legacy explosive 2,4,6-trinitrotoluene (TNT). Three isolates with high similarity to the Enterobacteriaceae(Enterobacter, Klebsiella) were able to transform TNT and NTO within 2 days, while isolates with high similarity to Serratia marcescens and Lactococcus lactis were able to transform RDX.


CONCLUSIONS
Termite endosymbionts harbor a range of metabolic activities and possess unique abilities to transform nitrogen-rich explosives.
US Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Miss., USA.
Karl J
KJ
Indest
Hillary L
HL
Eaton
Carina M
CM
Jung
Caly B
CB
Lounds
D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001711:Biotransformation; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D053834:Explosive Agents / Q000378:metabolism*; D020049:Isoptera / Q000382:microbiology*; D008969:Molecular Sequence Data; D009574:Nitro Compounds / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014227:Triazines / Q000378:metabolism; D014230:Triazoles / Q000378:metabolism; D014303:Trinitrotoluene / Q000378:metabolism
C505897:3-nitro-1,2,4-triazol-5-one; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D053834:Explosive Agents; D009574:Nitro Compounds; D012336:RNA, Ribosomal, 16S; D014227:Triazines; D014230:Triazoles; D014303:Trinitrotoluene; C009160:cyclonite