We demonstrate that tet(S), identical to tet(S) DNA Damage inhibitor found on the enterococcal conjugative transposon Tn6000, is responsible for the observed resistance. The gene is located on a small, low copy number plasmid and is flanked by IS1216 elements. The tet(S) gene is capable of excising from the plasmid together with one of the IS1216 elements. The plasmid contains a putative toxin/antitoxin system related to relBE. Deletion of the toxin, relE, did not result in plasmid instability but did increase the fitness of the mutant compared to the wild-type
“In the presence of vaporized p-cresol, Pseudomonas alkylphenolia KL28 forms specialized aerial structures (SAS). A transposon mutant of strain KL28 (C23) incapable of forming mature SAS was isolated. Genetic analysis of the C23 mutant revealed the transposon insertion in a gene (ssg) encoding a putative glycosyltransferase, which is homologous to the Pseudomonas aeruginosa PAO1 PA5001 gene. Deletion of ssg in KL28 caused the loss of lipopolysaccharide O antigen and altered the composition of the exopolysaccharide. Wild-type KL28 produced a fucose-, glucose- and mannose-rich exopolysaccharide, while the mutant exopolysaccharide completely lacked fucose and mannose, resulting in an exopolysaccharide with glucose as the major component. The mutant
strain showed reduced surface spreading, pellicle and biofilm formation, probably due to the cumulative effect of lipopolysaccharide truncation and altered exopolysaccharide composition. ABT-199 concentration Our results show that the ssg gene of KL28 is involved in both lipopolysaccharide and exopolysaccharide biosynthesis and thus plays an important role in cell surface properties and cell–cell interactions of P. alkylphenolia. Pseudomonas is a genus
of Gammaproteobacteria, capable of thriving in diverse environments ranging from hydrocarbon-contaminated water and soil to plant Reverse transcriptase and animal tissues (Rocchetta et al., 1999; Gibson & Parales, 2000; Stover et al., 2000; Ramos et al., 2001). Its ecological success stems in part from the outer cell membrane, which mainly consists of lipopolysaccharide. Lipopolysaccharide mediates interactions with the environment, reduces outer membrane permeability thereby increasing resistance to agents such as antibiotics and plays a critical role in cell motility, adhesion and attachment to a substratum/surface (Nikaido & Vaara, 1985; King et al., 2009; Lindhout et al., 2009). In addition to lipopolysaccharide, the exopolysaccharide that is secreted by bacteria also plays a physical role in cell–cell and cell–substratum attachment, thereby aiding the establishment of multicellular communities such as biofilms (Sutherland, 2001).