Victorian Ethical Optics: Innocent Eyes and Aberrant Bodies

Victorian Ethical Optics asks how artists and authors in the Victorian period answer the ethical question of how one should live with others by turning to a more specific one: how should one look at others? Looking would seem to necessarily lead to interpretation and judgment, but this book shows how Victorian artists and authors imagined other ethical and optical relations. In an era in which aberrant, deformed, and disabled bodies proliferated—particularly those bodies ravaged by industrial labor and poverty—the ideological and economic stakes of looking at such bodies peaked; moreover, as work became a gospel and the question of deservingness became central, looking at aberrant bodies was always a matter of ethics and politics. The aesthetic thinking of John Ruskin animates the ethical optics at the center of this book, as he advocates for “innocence of the eye,” which calls for a return to infantile sight of a kind that precedes judgment or classification. Although Ruskin understands such innocence to be an asymptote, optical innocence remains an ethical demand, and it is to this demand that this book attends. Encounters between normative and aberrant characters or figures within the texts and objects under discussion shape the encounter that the external reader or viewer has with those same aberrant bodies. Among the authors and artists included are Charles Dickens, George Eliot, Wilkie Collins, Henry Mayhew, Ford Madox Brown, John Everett Millais, other members of the Pre-Raphaelite Brotherhood, and English genre painters.

Chlamydiae, such as Chlamydia trachomatis and Chlamydia pneumoniae, can cause chronic infections. It is believed that persistent forms called aberrant bodies (ABs) might be involved in this process. AB formation seems to be a common trait of all members of the Chlamydiales order and is caused by distinct stress stimuli, such as β-lactam antibiotics or nutrient starvation. While the diverse stimuli inducing ABs are well described, no comprehensive morphological characterization has been performed in Chlamydiales up to now. We thus infected mammalian cells with the Chlamydia-related bacterium Waddlia chondrophila and induced AB formation using different stimuli. Their morphology, differences in DNA content and in gene expression were assessed by immunofluorescence, quantitative PCR, and reverse transcription PCR, respectively. All stimuli induced AB formation. Interestingly, we show here for the first time that the DNA gyrase inhibitor novobiocin also caused appearance of ABs. Two distinct patterns of ABs could be defined, according to their morphology and number: (i) small and multiple ABs versus (ii) large and rare ABs. DNA replication of W. chondrophila was generally not affected by the different treatments. Finally, no correlation could be observed between specific types of ABs and expression patterns of mreB and rodZ genes.

Aberrant chlamydial developmental forms in the gastrointestinal tract of pigs spontaneously and experimentally infected with Chlamydia suis

Screening Method for Hepatic Fibrinogen Storage Disease Associated with Congenital Hypofibrinogenemia

The chlamydiae are Gram-negative, obligate intracellular bacteria with a complex developmental cycle comprising a metabolically less-active, infectious stage, the elementary body (EB), and a metabolically more active stage, the reticulate body (RB). They are responsible for many acute and chronic diseases in humans and animals. In order to play a causative role in chronic diseases, chlamydiae would need to persist and to re-activate within infected cells/tissues for extended periods of time. Persistence in vitro is defined as viable but non-cultivable chlamydiae involving morphologically enlarged, aberrant, and nondividing RBs, termed aberrant bodies (AB). In vitro, alterations of the normal developmental cycle of chlamydiae can be induced by the addition of Interferon-? (IFN-?), tumor necrosis factor-a (TNF-a) and penicillin G exposure as well as amino acid or iron deprivation, monocyte infection and co-infection with viruses. In vivo, key questions include whether or not ABs occur in infected patients and animals and whether such ABs can contribute to prolonged, chronic inflammation, fibrosis, and scarring through continuing stimulation of the host immune system known from diseases such as trachoma, pelvic inflammatory disease, reactive arthritis and atherosclerosis. To date, the direct causal role in the pathogenesis of chlamydial infection and persistence in vivo has been questioned since there was no tractable animal model of chlamydial persistence so far. A very recent study was able to establish an experimental animal model of in vivo persistence, when C. muridarum vaginally-infected mice were gavaged with amoxicillin. Amoxicillin treatment induced C. muridarum to enter the persistent state in vivo. Recent in vivo data from patients indicate that viable but non-infectious developmental stages are present in the genital tract of chronically-infected women and that the gastrointestinal tract might be a reservoir for persistent chlamydial infections at other sites.

Chronic infections caused by obligate intracellular bacteria belonging to the Chlamydiales order are related to the formation of persistent developmental forms called aberrant bodies (ABs), which undergo DNA replication without cell division. These enlarged bacteria develop and persist upon exposure to different stressful conditions such as β-lactam antibiotics, iron deprivation and interferon-γ. However, the mechanisms behind ABs biogenesis remain uncharted. Using an RNA-sequencing approach, we compared the transcriptional profile of ABs induced by iron starvation to untreated bacteria in the Chlamydia-related species Waddliachondrophila, a potential agent of abortion in ruminants and miscarriage in humans. Consistent with the growth arrest observed following iron depletion, our results indicate a significant reduction in the expression of genes related to energy production, carbohydrate and amino acid metabolism and cell wall/envelope biogenesis, compared to untreated, actively replicating bacteria. Conversely, three putative toxin-antitoxin modules were among the most up-regulated genes upon iron starvation, suggesting that their activation might be involved in growth arrest in adverse conditions, an uncommon feature in obligate intracellular bacteria. Our work represents the first complete transcriptomic profile of a Chlamydia-related species in stressful conditions and sets the grounds for further investigations on the mechanisms underlying chlamydial persistence.

BackgroundChlamydiae induce persistent infections, which have been associated with a wide range of chronic diseases in humans and animals. Mixed infections with Chlamydia and porcine epidemic diarrhea virus (PEDV) may result in generation of persistent chlamydial infections. To test this hypothesis, an in vitro model of dual infection with cell culture-adapted PEDV and Chlamydia abortus or Chlamydia pecorum in Vero cells was established.ResultsInfected cultures were investigated by immunofluorescence (IF), transmission electron microscopy (TEM) and re-infection experiments. By IF, Chlamydia-infected cells showed normal inclusions after 39 hpi. Dual infections with Chlamydia abortus revealed a heterogenous mix of inclusion types including small inclusions consisting of aberrant bodies (ABs), medium-sized inclusions consisting of ABs and reticulate bodies and normal inclusions. Only aberrant inclusions were observable in dual infection experiments with Chlamydia pecorum and PEDV. TEM examinations of mixed infections with Chlamydia abortus and Chlamydia pecorum revealed aberrant chlamydial inclusions containing reticulate-like, pleomorphic ABs, which were up to 2 μm in diameter. No re-differentiation into elementary bodies (EBs) was detected. In re-infection experiments, co-infected cells produced fewer EBs than monoinfected cells.ConclusionsIn the present study we confirm that PEDV co-infection alters the developmental cycle of member species of the family Chlamydiaceae, in a similar manner to other well-described persistence induction methods. Interestingly, this effect appears to be partially species-specific as Chlamydia pecorum appears more sensitive to PEDV co-infection than Chlamydia abortus, as evidenced by TEM and IF observations of a homogenous population of aberrant inclusions in PEDV - Chlamydia pecorum co-infections.

The Chlamydiae phylum is comprised of obligate intracellular bacteria including human pathogens such as Chlamydia trachomatis and lesser-known Chlamydia-related bacteria like Waddlia chondrophila or Simkania negevensis. Despite broad differences, these bacteria share a similar development including a persistent state induced using stressors such as immune responses, nutrient starvation, or penicillin introduction. In microbiology, this persistent state is identified by enlarged bacteria, called aberrant bodies, which are unable to divide but are able to survive and resume the developmental cycle upon clearance of the stressor. Clinically, chlamydial persistence is thought to be linked to chronic disease and long-term infections with pathogenic strains. This review aims to share and discuss the latest discoveries made on the little-known mechanisms that take place during stress response. The results indicate that an inter-linked homeostasis between iron and tryptophan is required for effective bacterial proliferation. During stress, Chlamydiae attempt to compensate by inducing tight regulations of the tryptophan and iron acquisition operons. These compensations allow bacterial survival but result in the halting of cell division. As cell division is tightly linked to peptidoglycan synthesis and regulation, treatment with β-lactamase inhibitors can also exhibit an aberrant body phenotype.

Victorian Ethical Optics: Innocent Eyes and Aberrant Bodies by Natalie Prizel (review)

Only a few previous works investigated the involvement of Chlamydia pneumoniae (Chlamydophila pneumoniae) in arterial calcification. The present study investigated a possible association between C. pneumoniae and medial calcification. Carotid artery segments obtained by endarterectomy from 60 patients were examined by PCR and immunohistochemistry to identify the presence of C. pneumoniae. Arterial specimens showing double-positive (n = 17), double-negative (n = 22), and single-positive results (n = 21) were further analyzed by a combination of histology, immunohistochemistry, and electron microscopy. Medial calcification occurred in 10 of 17 (58.8%) C. pneumoniae double-positive arterial specimens, but no medial calcification was observed in any of 22 C. pneumoniae double-negative arterial specimens. Electron microscopy indicated C. pneumoniae in smooth muscle cells (SMCs) in foci of medial calcification. Medial SMCs showing damage to the cytoplasm and basement membrane contained the structures with the appearance of elementary, reticulate, and aberrant bodies of C. pneumoniae. The presence of C. pneumoniae in SMCs was confirmed by electron-microscopic immunocytochemistry. In the extracellular matrix, calcification was observed in C. pneumoniae aberrant bodies that exited the SMCs. The findings offer a new hypothesis of arterial calcification: they suggest that C. pneumoniae infection of medial SMCs may be associated with the pathophysiological events of arteriosclerotic calcification of the tunica media.

Despite broad genetic variability, members of the Chlamydiota phylum share a crucial stress response phenotype, the formation of aberrant bodies. However, how this response operates upon exposure to different kinds of stressors is still largely unknown. In Waddlia chondrophila, wcw_0502 RNA levels are upregulated in aberrant bodies induced by iron starvation. Wcw_0502 is a putative type III secretion system (T3SS) effector and has a homologue in every known chlamydial species, regardless of their host. However, the upregulation of the wcw_0502 gene expression upon iron starvation is not conserved in other chlamydial species such as Chlamydia trachomatis, Chlamydia pneumoniae, Simkania negevensis or Estrella lausannensis. Moreover, among all the stressors examined, only heat shock induced a strong upregulation of wcw_0502 and its C. trachomatis homologue, ctl0271. A Controlling Inverted Repeat of Chaperone Expression sequence is present in the promoter region of wcw_0502 and its homologues. We hypothesized that in the absence of stress, the conserved repressor HrcA, in association with the Hsp60 chaperone, binds this sequence and represses transcription. A decreased occupancy of HrcA and Hsp60 at the wcw_0502 promoter region was observed in aberrant bodies induced by iron starvation when compared to reticulate bodies, which may lead to wcw_0502 upregulation. The precise function of this newly described T3SS effector is still unclear. A cystine knot-like domain, a structural feature never described before in bacterial proteins, was found in the C-terminal region of Wcw_0502. This structure is described as highly resistant to proteolytic, chemical and thermic stressors, an advantageous property for a secreted protein with an increased production during stresses that impact protein integrity.

Tobacco smoke induces persistent infection of Chlamydophila pneumoniae in HEp-2 cells

Persistence, more recently termed the chlamydial stress response, is a viable but non-infectious state constituting a divergence from the characteristic chlamydial biphasic developmental cycle. Damage/danger associated molecular patterns (DAMPs) are normal intracellular components or metabolites that, when released from cells, signal cellular damage/lysis. Purine metabolite DAMPs, including extracellular ATP and adenosine, inhibit chlamydial development in a species-specific manner. Viral co-infection has been shown to reversibly abrogate Chlamydia inclusion development, suggesting persistence/chlamydial stress. Because viral infection can cause host cell DAMP release, we hypothesized DAMPs may influence chlamydial development. Therefore, we examined the effect of extracellular ATP, adenosine, and cyclic AMP exposure, at 0 and 14 hours post infection, on C. pecorum and C. trachomatis serovar E development. In the absence of de novo host protein synthesis, exposure to DAMPs immediately post or at 14 hours post infection reduced inclusion size; however, the effect was less robust upon 14 hours post infection exposure. Additionally, upon exposure to DAMPs immediately post infection, bacteria per inclusion and subsequent infectivity were reduced in both Chlamydia species. These effects were reversible, and C. pecorum exhibited more pronounced recovery from DAMP exposure. Aberrant bodies, typical in virus-induced chlamydial persistence, were absent upon DAMP exposure. In the presence of de novo host protein synthesis, exposure to DAMPs immediately post infection reduced inclusion size, but only variably modulated chlamydial infectivity. Because chlamydial infection and other infections may increase local DAMP concentrations, DAMPs may influence Chlamydia infection in vivo, particularly in the context of poly-microbial infections.

In the original publication [...].

Chlamydia spp. are important causes of acute and persistent/chronic infections. All Chlamydia spp. display a unique biphasic developmental cycle alternating between an infectious elementary body (EB) and a replicative form, the reticulate body (RB), followed by the multiplication of RBs by binary fission and progressive differentiation back into EBs. During its intracellular life, Chlamydia employs multiple mechanisms to ensure its persistence inside the host. These include evasion of diverse innate immune responses, modulation of host cell structure and endocytosis, inhibition of apoptosis, activation of pro-signaling pathways, and conversion to enlarged, non-replicative but viable “aberrant bodies” (ABs). Early research described several systems for Chlamydial persistence with a significant number of variables that make a direct comparison of results difficult. Now, emerging tools for genetic manipulations in Chlamydia and advances in global microarray, transcriptomics, and proteomics have opened new and exciting opportunities to understand the persistent state of Chlamydia and link the immune and molecular events of persistence with the pathogenesis of recurrent and chronic Chlamydial infections. This chapter reviews our current understanding and advances in the molecular biology of Chlamydia persistence.