title: Bacillus thuringiensis HD-1 Cry- : development of a safe, non-insecticidal simulant for Bacillus anthracis.
abstract: OBJECTIVE
  A representative simulant for spores of Bacillus anthracis is needed for field testing. Bacillus thuringiensis is gaining recognition as a suitable organism. A strain that does not form the insecticidal, parasporal crystals that are characteristic of this species is a more accurate physical representative of B. anthracis spores. We developed noninsecticidal derivatives of two isolates of B. thuringiensis HD-1.
  
  
  RESULTS
  Two plasmid-cured derivatives of B. thuringiensis HD-1, unable to make crystal toxins ('Cry(-) '), were isolated. These isolates and the existing Cry(-) strain, B. thuringiensis Al Hakam, were probed with PCR assays against the known insecticidal genes cry, vip and cyt. Their genomic DNA was sequenced to demonstrate a lack of insecticidal genes. This was confirmed by bioassays against a number of invertebrate species. Real-time PCR assays were developed to identify the B. thuringiensis HD-1 Cry(-) derivatives and an effective differential and selective medium was assessed.
  
  
  CONCLUSIONS
  All three Cry(-) isolates are devoid of known insecticidal determinants. The B. thuringiensis HD-1 Cry(-) derivatives can easily be recovered from soil and identified by PCR with some selectivity.
  
  
  CONCLUSIONS
  The B. thuringiensis HD-1 Cry(-) derivatives represent accurate, nongenetically manipulated simulants for B. anthracis with excellent human and environmental safety records.
authors.affiliation: Detection Department, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK.
authors.forename: A H
authors.initials: AH
authors.lastname: Bishop
authors.forename: C V
authors.initials: CV
authors.lastname: Robinson
mesh_terms: D000818:Animals; D001408:Bacillus anthracis; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000302:isolation & purification; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics; D004731:Endotoxins / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012988:Soil Microbiology; D013171:Spores, Bacterial
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus anthracis; Bacillus thuringiensis; noninsecticidal; safety; simulant; spore