Use of silkworm larvae to study pathogenic bacterial toxins

Muktadir S. Hossain, Hiroshi Hamamoto, Yasuhiko Matsumoto, Iony M. Razanajatovo, Jorge Larranaga, Chikara Kaito, Hiroshi Kasuga, Kazuhisa Sekimizu

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Injection of stationary phase culture-supernatants of Staphylococcus aureus and Pseudomonas aeruginosa into the hemolymph of silkworm larvae caused their death, whereas a culture-supernatant of a non-pathogenic strain of Escherichia coli did not. A culture-supernatant of a mutant of agr, a global virulence regulator of S. aureus that is required for exotoxin production, was much less toxic to silkworm larvae. A culture-supernatant of a disruption mutant of the S. aureus beta-toxin gene did not kill larvae, whereas one of a deletion mutant of alpha-toxin, gamma-toxin, or aureolysin killed larvae, indicating that the beta-toxin gene is required for staphylococcal supernatant-mediated killing of silkworm larvae. The 50% lethal doses (LD50) of staphylococcal alpha-toxin and beta-toxin, Pseudomonas exotoxin A and diphtheria toxin were 12 μg/g, 9 μg/g, 0.14 μg/g and 1.1 μg/g, respectively. As the purified toxins killed the larvae, silkworm larvae could be used as a model to study the actions of pathogenic bacterial toxins in animal bodies.

Original languageEnglish
Pages (from-to)439-444
Number of pages6
JournalJournal of biochemistry
Issue number3
Publication statusPublished - Sept 1 2006
Externally publishedYes


  • Animal model
  • Infection
  • Pathogenic bacterial toxins
  • Silkworm larva
  • Staphylococcus aureus

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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