Bacillus strain and antibiotic screening method

Abstract

A Bacillus strain has a chromosome with the following modifications: a mutation of a spoIIIE gene which blocks transfer of the prespore chromosome; a mutation which prevents loss of SpoOJ function from blocking sporulation; a first reporter gene dependent on σ F factor and placed at a location where impaired SpoOJ function leads to increased trapping in the prespore; and a second reporter gene having a promoter which is dependent on σ F factor and where impaired SpoOJ function leads to reduced trapping in the prespore. The strain is useful in a method of screening for putative antibiotics.

1 - 10 . (cancelled).  
     
     
         11 . a method of killing or inhibiting the growth of bacteria, which method comprises applying to the bacteria an agent to kill or inhibit the growth of the bacteria, said agent being identified by a method comprising: 
 providing a  Bacillus  strain having a functional SpoOJ gene and having a chromosome with the following modifications:    a) a mutation of a spoIIIE gene which blocks transfer of the prespore chromosome,    b) a mutation of soj which prevents loss of SpoOJ function from blocking sporulation, together with    c) a first reporter gene having a promoter which is dependent on σ F  factor and placed at a location on said chromosome where impaired SpoOJ function leads to increased trapping of said first reporter gene and hence to increased expression thereof in the prespore, and/or    d) a second reporter gene having a promoter which is dependent on σ F  factor and placed at a location on said chromosome where impaired SpoOJ function leads to reduced trapping of said second reporter gene and hence to reduced expression thereof in the prespore, and inducing said  Bacillus  strain to divide asymmetrically, as during sporulation, in the presence of the agent, and observing expression of the first and/or the second reporter gene to determine said agent.    
     
     
         12 . The method according to  claim 11 , wherein the first reporter gene and the second reporter gene are each fused to a σ F -dependent factor gpr promoter.  
     
     
         13 . The method according to  claim 11 , wherein the first reporter gene and the second reporter gene each express a different detectable enzyme.  
     
     
         14 . The method according to  claim 11 , wherein the expression of the first and/or second reporter gene(s) are/is observed by monitoring the levels of their expression products.  
     
     
         15 . The method according to  claim 14 , wherein the first and/or second reporter gene(s) are/is expressed as enzymes whose activities are observed by fluorimetry or spectrophotometry.  
     
     
         16 . The method according to  claim 11 , wherein the  Bacillus  strain is induced to divide asymmetrically and is contacted, just prior to asymmetric cell division, with said agent.