Abstract：
:Shigella flexneri kills macrophages through apoptosis, involving the induction of host cell DNA fragmentation and characteristic morphological changes. Shigella can only cause damage if it escapes from the phagolysosome into the cytoplasm. The S. flexneri cytotoxic genes have been localized to the ipa operon of shigella's virulence plasmid. ipaB, C and D deletion mutants are not invasive and therefore not cytotoxic. In order to distinguish genes involved in the escape from the phagolysosome as distinct from cytotoxicity, we constructed Shigella strains that secrete low amounts of Escherichia coli haemolysin (hly(low)). These strains can escape into the cytoplasm of the macrophage even in the absence of the invasion plasmid as verified by electron microscopy and resistance to chloroquine. Macrophages were infected with different ipa mutants expressing hly(low). Both delta ipaC hly(low) and delta ipaD hly(low) were cytotoxic whilst delta ipaB hly(low) and a hly(low) strain cured of shigella's pathogenicity plasmid were not. Furthermore, both delta ipaC hly(low) and delta ipaD hly(low) killed through apoptosis as shown by both changes in ultrastructural morphology and fragmentation of the host cell DNA. These results demonstrate that ipaB is essential for S. flexneri to induce apoptosis in macrophages.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Zychlinsky A,Kenny B,Ménard R,Prévost MC,Holland IB,Sansonetti PJdoi
10.1111/j.1365-2958.1994.tb00341.xsubject
Has Abstractpub_date
1994-02-01 00:00:00pages
619-27issue
4eissn
0950-382Xissn
1365-2958journal_volume
11pub_type
杂志文章abstract：:Clostridium difficile, an emerging nosocomial pathogen of increasing clinical significance, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The precise mechanisms by which toxin synthesis is regulated in response to environmental change have yet to be discove...
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journal_title：Molecular microbiology
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更新日期：1998-06-01 00:00:00
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pub_type： 杂志文章,评审
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更新日期：2004-09-01 00:00:00
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pub_type： 杂志文章
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更新日期：1989-01-01 00:00:00
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journal_title：Molecular microbiology
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