title: Factors affecting the activity of bovicin HC5, a bacteriocin from Streptococcus bovis HC5: release, stability and binding to target bacteria.
abstract: OBJECTIVE
  To determine the factors affecting the release, stability and binding of bovicin HC5 to sensitive bacteria.
  
  
  RESULTS
  Stationary phase Streptococcus bovis HC5 cultures had little cell-free bovicin HC5 activity until the final pH was <5.0, and even more bacteriocin was released by treatment with acidic NaCl (pH 2.0, 100 mmol l(-1)). Cultures grown with Tween 80 had more cell-free bovicin HC5 than untreated controls, but this nonionic detergent enhanced activity rather than release. Bovicin HC5 binding to S. bovis JB1 (a susceptible strain) was greater at pH values <6.0. Bovicin HC5 bound other sensitive Gram-positive bacteria, but not Gram-negative species. Cultures retained most of their activity for 35 days, but only if the final pH was <5.6. If the final pH was >5.6, peptidases destroyed much of the activity.
  
  
  CONCLUSIONS
  Bovicin HC5 remains cell associated until the culture pH is <5.0, but it can be easily dissociated from the cell surface by acidic NaCl. It is highly stable in acidic environments and only binds sensitive bacteria at pH values <6.0.
  
  
  CONCLUSIONS
  Streptococcus bovis HC5 does not have generally regarded as safe status. However, bovicin HC5 has a broad spectrum of activity and sensitive bacteria do not become resistant. Based on these results, bovicin HC5 may be a useful bacteriocin model.
authors.affiliation: Department of Microbiology, Cornell University, NY 14853, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Houlihan
authors.forename: J B
authors.initials: JB
authors.lastname: Russell
mesh_terms: D001430:Bacteriocins / Q000378:metabolism* / Q000493:pharmacokinetics; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D010447:Peptide Hydrolases / Q000378:metabolism; D011136:Polysorbates / Q000378:metabolism; D012995:Solubility; D016985:Streptococcus bovis / Q000378:metabolism*; D013501:Surface-Active Agents / Q000378:metabolism
chemical_list: D001430:Bacteriocins; D003470:Culture Media; D011136:Polysorbates; D013501:Surface-Active Agents; C514465:bovicin HC5, Streptococcus bovis HC5; D010447:Peptide Hydrolases; D005947:Glucose