The first point is whether phagocytic cells are required for germination and outgrowth of B.
In that model, infected macrophages were transported to the regional lymph nodes, and germination of the spores within macrophages at those sites was followed by outgrowth and then dissemination of extracellular bacilli.Įven with this fundamental work by Ross, two central issues related to the pathogenesis of anthrax in animal models are sources of controversy. She described the uptake of spores by alveolar macrophages following intratracheal or aerosol delivery in guinea pigs. One of the first and still considered seminal reports on this subject was published in 1957 by Ross ( 30). The impact of this bioterrorism event on those individuals specifically and on society in general provided the impetus for researchers to further define the early steps in establishment of pulmonary anthrax, with the goal of developing potential intervention strategies. mail in 2001 led to 11 occurrences of cutaneous anthrax and 11 cases of inhalational anthrax, with five deaths in the latter group (summarized in reference 20). The dissemination of infective Bacillus anthracis spores in the U.S. anthracis spore germination is the lungs. We conclude that in this animal system, the primary site of B. In contrast, mediastinal lymph nodes remained nonluminescent throughout the infection. After 24 h, few free spores were observed in the alveolar spaces most of the spores detected by immunofluorescence were in the cytoplasm of interstitial macrophages. By 6 h after infection, polymorphonuclear leukocytes with intracellular spores were evident in the alveolar spaces. Microscopic histochemical and immunofluorescence studies on luminescent lung sections and imprints revealed that macrophages were the first cells in contact with the B. While luminescence only became evident in live animals at 18 h, dissection after sacrificing infected mice at earlier time points revealed luminescence in lung tissue at 30 min after intranasal infection. Mice were monitored for up to 14 days with the Xenogen In Vivo Imaging System. We then infected A/J mice intranasally with spores that harbored the germination reporter. In contrast, Sterne transformed with a similarly constructed plasmid with lux expression under control of the protective antigen promoter displayed luminescence only during vegetative growth. anthracis Sterne transformed with our sspBp:: lux plasmid was only luminescent during germination. subtilis, sspB-driven synthesis of luciferase during sporulation results in incorporation of the enzyme in spores. For that purpose, we constructed a reporter plasmid with the lux operon under control of the spore small acid-soluble protein B ( sspB) promoter. We sought to visualize the site of Bacillus anthracis spore germination in vivo.
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