کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4359401 | 1300504 | 2007 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Inactivation of ppk differentially affects virulence and disrupts ATP homeostasis in Salmonella enterica serovars Typhimurium and Gallinarum
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
ایمنی شناسی و میکروب شناسی
میکروبیولوژی و بیوتکنولوژی کاربردی
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چکیده انگلیسی
Polyphosphate is involved in resistance to stress in a number of bacterial species; however, its role in the virulence of Salmonella enterica serovars which differ in their host range has not been described. We examined the role of polyphosphate kinase in infection, growth and survival of S. Typhimurium (broad-host range) and S. Gallinarum (avian-adapted). We also used ppk mutants to assess the downstream effects on intracellular ATP levels. ppk mutants had significantly (PÂ <Â 0.05) elevated ATP in stationary phase compared to the wild-type and, depending on the serovar, were defective in growth, survival and virulence. The virulence of S. Typhimurium ppk::SpcStr was significantly (PÂ <Â 0.05) attenuated following oral infection of both Rhode Island Red chickens and BALB/c mice. In contrast, inactivation of the ppk gene of S. Gallinarum did not affect growth or virulence. The differential contribution of polyphosphate to the virulence of S. Typhimurium and S. Gallinarum may reflect aspects of the pathogenesis and host range of these serovars. The ppk mutant of both serovars survived significantly less well (PÂ <Â 0.05) in a saline starvation-survival model, relative to the respective parent. The effect of ppk mutation on survival was formally described by fitting the data to the Weibull model and by estimation of kmax. Measurement of rpoS promoter activity using a lacZ transcriptional fusion demonstrated repression of rpoS in a ppk background, confirming a role for polyphosphate in RpoS induction. Together the data indicate the crucial importance of maintaining stable intracellular ATP during infection and nutritional stress. We suggest that polyphosphate plays a central role in homeostasis during growth and stress.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Research in Microbiology - Volume 158, Issue 1, JanuaryâFebruary 2007, Pages 79-85
Journal: Research in Microbiology - Volume 158, Issue 1, JanuaryâFebruary 2007, Pages 79-85
نویسندگان
Alisdair McMeechan, Margaret A. Lovell, Tristan A. Cogan, Kerrie L. Marston, Tom J. Humphrey, Paul A. Barrow,