HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Kahane, S. Articles by Friedman, M. G. Search for Related Content PubMed PubMed Citation Articles by Kahane, S. Articles by Friedman, M. G. Agricola Articles by Kahane, S. Articles by Friedman, M. G.

The growth cycle of Simkania negevensis

Department of Virology, Faculty of Health Sciences, Ben Gurion University of the Negev, PO Box 653, Beer Sheva, Israel84105-IL¹

Author for correspondence: Maureen G. Friedman. Tel: +972 8 6403857. Fax: +972 8 6276215. e-mail: maureen{at}bgumail.bgu.ac.il

Simkania negevensis, a bacterium formerly referred to as ‘the micro-organism Z’ or ‘Simkania Z’, belongs to the order Chlamydiales, assigned to the family Simkaniaceae. The purpose of this study was to investigate the production of Simkania negevensis progeny in infected cells in comparison with the well-documented Chlamydiaceae developmental cycle. It was found that replicating Simkania negevensis in Vero cells resembled the reticulate bodies of all known chlamydial species: in electron micrographs they were reticulated, homogeneously staining, and often caught in the process of binary division. These replicative forms were found in low abundance shortly after infection, but by 3 days post-infection they were the most prevalent particles in host cells. Electron-dense forms of Simkania negevensis began to appear on the third day post-infection, but quantitatively did not account for the high titre of infectivity in extracts from these host cells. These had both electron-dense and electron-lucent areas, a characteristic seen only in a few chlamydial species. Simkania negevensis infectivity did not appreciably change during the ensuing 12 days required for host cell lysis, despite an eightfold increase in the proportion of electron-dense bacteria over this time. The emergence of electron-dense bodies, increase in infectivity and host-cell lysis were not synchronized developmental events. This is a novel finding in Chlamydiales spp. and suggests that Simkania negevensis will provide new perspectives in the mechanisms of chlamydial intracellular growth.

Keywords: Chlamydia-like micro-organism, infectivity, Simkania

Abbreviations: EB, elementary body; EM, electron microscopy; IFU, infectious-centre-forming unit; p.i., post-infection; PIPA, plate immunoperoxidase assay; RB, reticulate body

This article has been cited by other articles:

				A. Collingro, S. Poppert, E. Heinz, S. Schmitz-Esser, A. Essig, M. Schweikert, M. Wagner, and M. Horn Recovery of an environmental chlamydia strain from activated sludge by co-cultivation with Acanthamoeba sp. Microbiology, January 1, 2005; 151(1): 301 - 309. [Abstract] [Full Text] [PDF]

				G. Soldati, Z. H. Lu, L. Vaughan, A. Polkinghorne, D. R. Zimmermann, J. B. Huder, and A. Pospischil Detection of Mycobacteria and Chlamydiae in Granulomatous Inflammation of Reptiles: A Retrospective Study Vet. Pathol., July 1, 2004; 41(4): 388 - 397. [Abstract] [Full Text] [PDF]

				S. Kahane, N. Platzner, B. Dvoskin, A. Itzhaki, and M. G. Friedman Evidence for the Presence of Simkania negevensis in Drinking Water and in Reclaimed Wastewater in Israel Appl. Envir. Microbiol., June 1, 2004; 70(6): 3346 - 3351. [Abstract] [Full Text] [PDF]