The Relation of the Psittacosis Group (Chlamydiae) to Bacteria and Viruses

Moulder, James W.

doi:10.1146/annurev.mi.20.100166.000543

Cited by 115 publications

(53 citation statements)

References 38 publications

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“…We therefore examined the metabolic capabilities of R. typhi and C. psittaci (strain 6BC), which are cytoplasmic (2,10) and phagosomal pathogens (2,50,56) of eukaryotes, respectively. Both of these organisms are representative members of the two orders ofrickettsias, and both were shown to metabolize glutamate (2,57). In contrast to C. burnetii but in accord with compartmentalized replication, both R. typhi and C. psittaci metabolized glutamate optimally at about pH 7.0-7.4, and neither metabolized glucose to a detectable level at any pH examined (58).…”

Section: Methodsmentioning

confidence: 99%

Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii.

Hackstadt¹,

Williams²

1981

Proc. Natl. Acad. Sci. U.S.A.

301

290

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Coxiella burnetti, the etiologic agent of Q fever, is an oligate intracellular parasite of eukaryotes. Unlike the majority of successful bacterial parasites, which escape the bactericidal environment of the phagolysosome by various means, C. burnetii multiplies only in the phagolysosome. In view of the relatively harsh environment inhabited by C. burnetii, we have examined (i) the in vitro metabolism of glucose and glutamate by whole cells of C. burnetii under conditions designed to approximate the pH within the phagolysosome and (ii) the effect of manipulation of the phagolysosomal pH by lysosomotropic amines on the replication of C. burnetii in chicken embryo fibroblasts. The transport, catabolism, and incorporation of both glucose and glutamate were found to be highly stimulated by acidic conditions, whereas at pH 7.0 metabolism of these substrates was minimal. The transport processes were shown to be energy dependent and highly sensitive to inhibition by uncouplers of oxidative phosphorylation. Increasing the phagolysosomal pH ofinfected chicken embryo fibroblasts by use of the lysosomotropic agents chloroquine, methylamine, or ammonium chloride inhibited the multiplication of C. burnetii, thus demonstrating the in vivo requirement for the acidic conditions ofthe phagolysosome. This apparent dependence upon phagosome-lysosome fusion to generate pH conditions favorable to C. burnetii replication suggests a unique biochemical mechanism of parasite activation. A pathogenic mechanism based on regulation of microbial metabolism by H+-dependent stimulation of cell function is proposed.

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Section: Methodsmentioning

confidence: 99%

Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii.

Hackstadt¹,

Williams²

1981

Proc. Natl. Acad. Sci. U.S.A.

301

290

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“…In 1966, Moulder published a comprehensive review of the growth, division, structure, chemical composition, and metabolism of the group, taking into account the definitions of viruses and bacteria that had recently been proposed by Lwoff and Stanier, respectively. He concluded fairly unequivocally that chlamydiae were intracellular bacteria, with a distinctive developmental cycle and unique structure (151). The Taxonomy Committee of the American Society for Microbiology unified these organisms in the genus Chlamydia and supported their status as bacteria (166).…”

Section: Causative Organism Historical Perspectivementioning

confidence: 99%

Diagnosis and Assessment of Trachoma

et al. 2004

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Trachoma is caused by Chlamydia trachomatis. Clinical grading with the WHO simplified system can be highly repeatable provided graders are adequately trained and standardized. At the community level, rapid assessments are useful for confirming the absence of trachoma but do not determine the magnitude of the problem in communities where trachoma is present. New rapid assessment protocols incorporating techniques for obtaining representative population samples (without census preparation) may give better estimates of the prevalence of clinical trachoma. Clinical findings do not necessarily indicate the presence or absence of C. trachomatis infection, particularly as disease prevalence falls. The prevalence of ocular C. trachomatis infection (at the community level) is important because it is infection that is targeted when antibiotics are distributed in trachoma control campaigns. Methods to estimate infection prevalence are required. While culture is a sensitive test for the presence of viable organisms and nucleic acid amplification tests are sensitive and specific tools for the presence of chlamydial nucleic acids, the commercial assays presently available are all too expensive, too complex, or too unreliable for use in national programs. There is an urgent need for a rapid, reliable test for C. trachomatis to assist in measuring progress towards the elimination of trachoma

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“…Although initially believed to be a virus [1], Gram-negative Chlamydiae were the first 16 obligate intracellular bacteria with a biphasic lifecycle to be described [2]. 17…”

Section: Introduction 14 15mentioning

confidence: 99%

Making connections: snapshots of chlamydial type III secretion systems in contact with host membranes

Dumoux

Nans

Saibil

et al. 2015

Current Opinion in Microbiology

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Chlamydiae are obligate intracellular bacterial pathogens with an unusual biphasic lifecycle, which is underpinned by two bacterial forms of distinct structure and function. Bacterial entry and replication require a type III secretion system (T3SS), a widely conserved nanomachine responsible for the translocation of virulence effectors into host cells. Recent cell biology experiments supported by electron and cryo-electron tomography have provided fresh insights into Chlamydia-host interactions. In this review, we highlight some of the recent advances, particularly the in situ analysis of T3SSs in contact with host membranes during chlamydial entry and intracellular replication, and the role of the host rough endoplasmic reticulum at the recently described intracellular 'pathogen synapse'.

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The Relation of the Psittacosis Group (Chlamydiae) to Bacteria and Viruses

Cited by 115 publications

References 38 publications

Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii.

Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii.

Diagnosis and Assessment of Trachoma

Making connections: snapshots of chlamydial type III secretion systems in contact with host membranes

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