Biological properties and structure of the lipopolysaccharide of a vaccine strain of Francisella tularensis generated by inactivation of a quorum sensing system gene qseC.
A knockout mutant with a deletion in a quorum sensing system gene qseC was generated from the vaccine strain Francisella tularensis 15 by site-directed mutagenesis. The variant with the inactivated gene qseC differed from the parental strain in growth rate on solid nutrient medium but had the same growth dynamics in liquid nutrient medium. The mutation abolished almost completely the resistance of the vaccine strain to normal rabbit serum and its ability to survive in macrophages; in addition, the strain lost the residual virulence. A significant phenotypic alteration was observed in the lipopolysaccharide of F. tularensis. Particularly, the mutant strain synthesized no noticeable amount of the lipopolysaccharide with the high-molecular-mass O-polysaccharide, presumably as a result of impairing biosynthesis of the repeating unit, namely, a loss of the ability to incorporate a formyl group, an N-acyl substituent of 4-amino-4,6-dideoxy-D-glucose.
Mokrievich
A N
AN
State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, 142279, Russia. mokrievich@obolensk.org
Kondakova
A N
AN
Valade
E
E
Platonov
M E
ME
Vakhrameeva
G M
GM
Shaikhutdinova
R Z
RZ
Mironova
R I
RI
Blaha
D
D
Bakhteeva
I V
IV
Titareva
G M
GM
Kravchenko
T B
TB
Kombarova
T I
TI
Vidal
D
D
Pavlov
V M
VM
Lindner
B
B
Dyatlov
I A
IA
Knirel
Yu A
YA
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001428:Bacterial Vaccines / Q000276:immunology; D005604:Francisella tularensis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D055786:Gene Knockout Techniques; D008070:Lipopolysaccharides / Q000737:chemistry*; D016297:Mutagenesis, Site-Directed; D019081:O Antigens / Q000737:chemistry; D010641:Phenotype; D053038:Quorum Sensing / Q000235:genetics*; D011817:Rabbits; D021241:Spectrometry, Mass, Electrospray Ionization; D014774:Virulence
D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D008070:Lipopolysaccharides; D019081:O Antigens