title: Bacillus megaterium spore germination is influenced by inoculum size.
abstract: OBJECTIVE
  The effect of spore density on the germination (time-to-germination, percent germination) of Bacillus megaterium spores on tryptic soy agar was determined using direct microscopic observation.
  
  
  RESULTS
  Inoculum size varied from approximately 10(3) to 10(8) cfu ml(-1) in a medium where pH=7 and the sodium chloride concentration was 0.5% w/v. Inoculum size was measured by global inoculum size (the concentration of spores on a microscope slide) and local inoculum size (the number of spores observed in a given microscope field of observation). Both global and local inoculum sizes had a significant effect on time-to-germination (TTG), but only the global inoculum size influenced the percentage germination of the observed spores.
  
  
  CONCLUSIONS
  These results show that higher concentrations of Bacillus megaterium spores encourage more rapid germination and more spores to germinate, indicating that low spore populations do not behave similarly to high spore populations.
  
  
  CONCLUSIONS
  A likely explanation for the inoculum size-dependency of germination would be chemical signalling or quorum sensing between Bacillus spores.
authors.affiliation: Food Risk Analysis Initiative, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Caipo
authors.forename: S
authors.initials: S
authors.lastname: Duffy
authors.forename: L
authors.initials: L
authors.lastname: Zhao
authors.forename: D W
authors.initials: DW
authors.lastname: Schaffner
mesh_terms: D001410:Bacillus megaterium / Q000254:growth & development / Q000502:physiology*; D015169:Colony Count, Microbial; D003470:Culture Media; D008853:Microscopy; D008954:Models, Biological; D013171:Spores, Bacterial / Q000502:physiology*
chemical_list: D003470:Culture Media