Electron Microscopic Observations on the Effects of Penicillin on the Morphology ofChlamydia psittaci

Abstract

L ceRs were infected at high multiplicity with meningopneumonitis organisms and incubated in medium containing 200 units per ml of penicillin. At intervals up to 48 hr after infection, cells were removed and thin sections were prepared for electron microscopic studies on the morphology of the developing organism. Penicillin had no effect on the initial reorganization of the infecting elementary body to form the developmental reticulate body (RB), and, up to 12 hr after infection, the treated and untreated cultures were identical. After that time, however, penicillin-treated organisms showed striking differences in that binary fission was prevented, large abnormal RB forms were seen in great numbers, masses of RB cytoplasmic membranes and envelopes were formed within and outside the RB itself, and large numbers of empty or partially filled small vesicles were pinched off the RB. After 36 hr immature nucleoids were formed within the RB. Throughout all of this period, both the outer cell envelope and the cytoplasmic membrane of these RB were recognized. When infected cells were transferred into penicillin-free medium, the abnormal RB showed recovery to form normal RB both by a budding-like process and by internal fragmentation or subdivision rather like endosporulation. We have concluded that penicillin inhibits binary fission and prevents the synthesis of certain components essential for the formation of the elementary body envelope. Organisms in the genus Chlamydia undergo a complex growth cycle in which the infectious form [elementary body (EB)] penetrates a sus

Mixed infections with Chlamydia and porcine epidemic diarrhea virus - a new in vitro model of chlamydial persistence

“…It should be noted, that in the latter study, chlamydial persistence was not demonstrated using the characteristic features now associated with the morphology of persistent chlamydial infections. Detailed description of electron microscopic observations on the effects of penicillin on the morphology of Chlamydia psittaci Cal10 in L cells showing aberrant chlamydial stages were published by Matsumoto and Manire [13].…”

“…Persistent forms of Chlamydia trachomatis and Chlamydia pneumoniae are well described by their characteristic electron microscopic appearance [2,13,14]. Thus, chlamydial ultrastructure in single and co-infected cells was compared by transmission electron microscopy (TEM).…”

Drosophila melanogaster S2 cells: a model system to study Chlamydia interaction with host cells

“…Furthermore, treatment of L2-infected S2 cells with penicillin resulted in enlarged RBs (unpubl. data), similar to the changes reported in mammalian cells (Matsumoto and Manire, 1970;Kramer and Gordon, 1971). The fact that IncG was produced and localized to the inclusion suggests that Chlamydia was metabolically active and modified the inclusion as it does during mammalian infection.…”

Chlamydia persistence – a tool to dissect chlamydia–host interactions

“…Penicillin-exposure inhibited C. psittaci RB to EB conversion, forming greatly enlarged, irregular, less electrondense RB (i.e. AB) that shed membrane blebs [5]. Amoxicillinexposed, Chlamydia muridarum-infected murine epithelial cells show the characteristic AB morphology (Fig.…”