HEAT-SHOCK RESPONSE AND GROEL-SEQUENCE OF BARTONELLA-HENSELAE AND BARTONELLA-QUINTANA

Transmission of Bartonella species from edoparasites to the mammalian host involves adaptation to thermal and other forms of stress. in orde r to better understand this process, the heat shock response of Barton ella henselae and Bartonella quintana was studied. Cellular proteins s ynthesized after shift to higher temperatures were intrinsically label led with [S-35]methionine and analysed by gel electrophoresis and fluo rography. The apparent molecular masses of three of the major heat sho ck proteins produced by the two Bartonella species were virtually iden tical, migrating at 70, 60 and 10 kDa. A fourth major shock protein wa s larger in B. quintana (20 kDa) than in B. henselae (17 kDa). The max imum heat shock response in B. quintana and B. henselae was observed a t 39 degrees C and 42 degrees C, respectively. The groEL genes of both Bartonella species were amplified, sequenced and compared to other kn own groEL genes. The phylogenetic tree based on the groEL alignment pl aces B. quintana and B. henselae in a monophyletic group with Bartonel la bacilliformis. the deduced amino acid sequences of Bartonella GroEL homologues contain signature sequences that are uniquely shared by me mbers of the Gram-negative alpha-purple subdivision of bacteria, which live within eukaryotic cells. Recombinant His(6)-GroEL fusion protein s were expressed in Escherichia coli to generate specific rabbit antis era. The GroEL antisera were used to confirm the identity of the 60 kD a Bartonella heat shock protein. These studies provide a foundation fo r evaluating the role of the heat shock response in the pathogenesis o f Bartonella infection.