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Listeria monocytogenes is a facultative intracellular bacterial pathogen that is frequently associated with food-borne infection. Of particular concern is the ability of L. monocytogenes to breach the blood-brain barrier, leading to life-threatening meningitis and encephalitis. The mechanisms used by bacterial pathogens to infect the brain are not fully understood. Here we show that L. monocytogenes is able to utilize vimentin for invasion of host cells. Vimentin is a type III intermediate filament protein within the cytosol but is also expressed on the host cell surface. We found that L. monocytogenes interaction with surface-localized vimentin promoted bacterial uptake. Furthermore, in the absence of vimentin, L. monocytogenes colonization of the brain was severely compromised in mice. The L. monocytogenes virulence factor InlF was found to bind vimentin and was necessary for optimal bacterial colonization of the brain. These studies reveal a novel receptor-ligand interaction that enhances infection of the brain by L. monocytogenes and highlights the importance of surface vimentin in host-pathogen interactions.

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Foaming in products based on micellar solutions has considerable importance in various consumer applications, such as washing and cleaning. In this work, the effects of surfactant concentration, oil content, and salts containing mono-, di-, and trivalent counterions on foam formation and stability were studied. The foams were generated by employing the Blender Test. The presence of salts caused a significant reduction in foam volume. Effectiveness of the salts followed the sequence Al 3+ > Ca 2+ > Na + . However, the foam collapse rate was slower in the presence of salt. The rate of adsorption of surfactant molecules at the air−water interface was augmented by salt. Oil reduced the foam volume and its stability. The entering, spreading, and bridging coefficients were calculated. These coefficients qualitatively explained the stability of foam in the presence of oil.

Ammonia is a major source of water pollution. One of the most common methods for removal of ammonia from water is oxidation. In this work, ozonation of ammonia using microbubbles was studied in a pilot plant. The experimental results indicate that ozone microbubbles were quite effective in oxidizing ammonia. Oxidation of ammonia was effective at high pH and high ozone generation rates. Ozonation was found to occur by direct reaction of ozone with ammonia at the higher pH. However, the hydroxyl radicals were also involved at the lower pH. Bromide ions acted as a catalyst in the ozonation process, and a faster rate of oxidation of ammonia and lower yield of nitrate was observed. The volumetric mass transfer coefficient of ozone in water was determined. It increased with the increasing rate of ozone generation and the pH of the medium.

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Mycobacterium avium subspecies paratuberculosis ( M. ap ) is the causative agent of paratuberculosis or Johne's disease (JD) in herbivores with potential involvement in cases of Crohn's disease in humans. JD is spread worldwide and is economically important for both beef and dairy industries. Generally, pathogenic ovine strains ( M. ap -S) are mainly found in sheep while bovine strains ( M. ap -C) infect other ruminants (e.g. cattle, goat, deer), as well as sheep. In an effort to characterize this emerging infection in dromedary/Arabian camels, we successfully cultured M. ap from several samples collected from infected camels suffering from chronic, intermittent diarrhea suggestive of JD. Gene-based typing of isolates indicated that all isolates belong to sheep lineage of strains of M. ap ( M. ap -S), suggesting a putative transmission from infected sheep herds. Screening sheep and goat herds associated with camels identified the circulation of this type in sheep but not goats. The current genome-wide analysis recognizes these camel isolates as a sub-lineage of the sheep strain with a significant number of single nucleotide polymorphisms (SNPs) between sheep and camel isolates (∼1000 SNPs). Such polymorphism could represent geographical differences among isolates or host adaptation of M. ap during camel infection. To our knowledge, this is the first attempt to examine the genomic basis of this emerging infection in camels with implications on the evolution of this important pathogen. The sequenced genomes of M. ap isolates from camels will further assist our efforts to understand JD pathogenesis and the dynamic of disease transmission across animal species.