Developmental stage-specific metabolic and transcriptional activity of Chlamydia trachomatis in an axenic medium

Abstract

Chlamydia trachomatis is among the most clinically significant human pathogens, yet their obligate intracellular nature places severe restrictions upon research. Chlamydiae undergo a biphasic developmental cycle characterized by an infectious cell type known as an elementary body (EB) and an intracellular replicative form called a reticulate body (RB). EBs have historically been described as metabolically dormant. A cell-free (axenic) culture system was developed, which showed high levels of metabolic and biosynthetic activity from both EBs and RBs, although the requirements differed for each. EBs preferentially used glucose-6-phosphate as an energy source, whereas RBs required ATP. Both developmental forms showed increased activity when incubated under microaerobic conditions. Incorporation of isotopically labeled amino acids into proteins from both developmental forms indicated unique expression profiles, which were confirmed by genome-wide transcriptional analysis. The described axenic culture system will greatly enhance biochemical and physiological analyses of chlamydiae.

Structural and Biochemical Characterization of Chlamydia trachomatis Hypothetical Protein CT263 Supports That Menaquinone Synthesis Occurs through the Futalosine Pathway

“…The medically important human pathogen C. trachomatis is capable of oxidative level phosphorylation, generating ATP through the electron transport chain (30). However, the source of electron shuttling quinones has been unclear and is further compounded by the presence of four genes with homology to enzymes common to both the UQ and MK biosynthetic pathways (10).…”

The Rebirth of Culture in Microbiology through the Example of Culturomics To Study Human Gut Microbiota

“…However, 16S rRNA sequencing also exhibits several biases, notably a high degree of conservation in some genera (49). Genomic sequences from microorganisms constitute a major source of genetic information that could provide unequaled data for the development and identification of genotyping tools as well as for the design of culture media (260)(261)(262)(263). We believe that microbiogenomics, which consists of sequencing of the genomes of all microorganisms cultured for which no such sequences are yet available, will be a major advance in clinical microbiology (Fig.…”

Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen

“…However, targeting RBs for transformation within infected cells requires exogenous DNA to traverse through four lipid bilayers (the host plasma membrane, the inclusion membrane, and the RB outer and inner membranes) before encountering the RB chromosome. RBs can be isolated and potentially transformed in axenic media (48). However, because RBs are noninfectious, their utility in pathogenesis studies is limited unless methods are developed to permit their transition to EBs.…”