Anti-Salmonella type H-k Polyclonal antibody

In the present study, we characterized the involvement of Lon protease in bacterial virulence and intracellular survival inSalmonellaunder abiotic stress conditions resembling the conditions of a natural infection. Wild type (JOL401) and thelonmutant (JOL909)SalmonellaTyphimurium were exposed to low temperature, pH, osmotic, and oxidative stress conditions and changes in gene expression profiles related to virulence and metal ion uptake were investigated. Expression of candidate genesinvFandhilCofSalmonellaPathogenicity Island (SPI)-1 andsifAandsseJof SPI-2 revealed that Lon protease controls SPI-1 genes and not SPI-2 genes under all stress conditions tested. Thelonmutant exhibited increased accumulation of hydroxyl (OH center dot) ions that lead to cell damage due to oxidative stress. This oxidative damage can also be linked to an unregulated influx of iron due to the upregulation of ion channel genes such asfepAin thelonmutant. The deletion oflonfrom theSalmonellagenome causes oxidative damage and increased expression of virulence genes. It also prompts the secretion of host pro-inflammatory cytokines leading to early clearance of the bacteria from host cells. We conclude that poor bacterial recovery from mice infected with thelonmutant is a result of disrupted bacterial intracellular equilibrium and rapid activation of cytokine expression leading to bacterial lysis.

Thymus algeriensis Bioss & Reut is an Algerian native plant traditionally used for culinary and medicinal purposes. To evaluate the in vivo antioxidant and antimicrobial properties of T. algeriensis, phenolic compounds were extracted using hydromethanolic solutions and administrated to Swiss albinos mice. It was observed that the plasma antioxidant capacity increased, as well as catalase and glutathione levels, whereas malondialdehyde decreased. In vitro assays confirmed that the extract scavenged 2,2-diphenyl-1-picrylhydrazyl, DPPH center dot (7 mu g/mL), chelated (EC50: 512 mu g/mL) and reduced iron ions (5.3 mM FeSO4/g), and inhibited beta-carotene bleaching (90% at 2 mg/mL). Antibacterial effects were also observed towards Salmonella typhimurium and Proteus mirabilis. However, the methanolic fraction obtained by reversed solid phase cartridge, showed antibacterial activity against Escherichia coli (MIC = 9.37 mg/mL), Proteus mirabilis (MIC = 4.68 mg/mL), Salmonella typhimurium (MIC = 7.06 mg/mL), Micrococcus luteus (MIC = 7.03 mg/mL), and Bacillus cereus (MIC = 2.34 mg/mL). UHPLC-DAD-ESI-MSn analysis showed that these properties could result from rosmarinic acid, caffeoyl rosmaniric acid, and kaempferol and eriodictyol glycoside derivatives. These results pave the way for the understanding of T. algeriensis traditional applications and its use for the development of novel food applications.