{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T13:55:23Z","timestamp":1790776523982,"version":"4.1.0"},"reference-count":61,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,12,9]],"date-time":"2021-12-09T00:00:00Z","timestamp":1639008000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:p>Cell size regulation in bacteria is a function of two basic cellular processes: the expansion of the cell envelope and its constriction at spatially defined points at what will eventually become the division plane. In most bacterial species, both cell wall expansion and restriction are dependent on peptidoglycan (PG), a structural polymer comprised of sugars and amino acids that imparts strength and rigidity to bacterial membranes. Pathogenic <jats:italic>Chlamydia<\/jats:italic> species are unique in that their cell walls contain very little PG, which is restricted almost entirely to the apparent division plane of the microbe\u2019s replicative forms. Very little is known about the degree to which PG affects the size and shape of <jats:italic>C. trachomatis<\/jats:italic> during its division process, and recent studies suggest the process is initiated <jats:italic>via<\/jats:italic> a polarized mechanism. We conducted an imaging study to ascertain the dimensions, orientation, and relative density of chlamydial PG throughout the organism\u2019s developmental cycle. Our analysis indicates that PG in replicating <jats:italic>C. trachomatis<\/jats:italic> can be associated with four, broad structural forms; polar\/septal disks, small\/thick rings, large rings, and small\/thin rings. We found that PG density appeared to be highest in septal disks and small\/thick rings, indicating that these structures likely have high PG synthesis to degradation ratios. We also discovered that as <jats:italic>C. trachomatis<\/jats:italic> progresses through its developmental cycle PG structures, on average, decrease in total volume, indicating that the average cell volume of chlamydial RBs likely decreases over time. When cells infected with <jats:italic>C. trachomatis<\/jats:italic> are treated with inhibitors of critical components of the microbe\u2019s two distinct PG synthases, we observed drastic differences in the ratio of PG synthesis to degradation, as well as the volume and shape of PG-containing structures. Overall, our results suggest that <jats:italic>C. trachomatis<\/jats:italic> PG synthases differentially regulate the expansion and contraction of the PG ring during both the expansion and constriction of the microbe\u2019s cell membrane during cell growth and division, respectively.<\/jats:p>","DOI":"10.3389\/fmicb.2021.733850","type":"journal-article","created":{"date-parts":[[2021,12,9]],"date-time":"2021-12-09T10:53:35Z","timestamp":1639047215000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":18,"title":["Localized Peptidoglycan Biosynthesis in Chlamydia trachomatis Conforms to the Polarized Division and Cell Size Reduction Developmental Models"],"prefix":"10.3389","volume":"12","author":[{"given":"George W.","family":"Liechti","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,12,9]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"e1005822","DOI":"10.1371\/journal.ppat.1005822","article-title":"Polarized cell division of Chlamydia trachomatis","volume":"12","author":"Abdelrahman","year":"2016","journal-title":"PLoS Pathog."},{"key":"ref2","doi-asserted-by":"publisher","first-page":"420","DOI":"10.1128\/jb.151.1.420-428.1982","article-title":"Chlamydia trachomatis has penicillin-binding proteins but not detectable muramic acid","volume":"151","author":"Barbour","year":"1982","journal-title":"J. Bacteriol."},{"key":"ref3","doi-asserted-by":"publisher","first-page":"686","DOI":"10.1128\/mr.58.4.686-699.1994","article-title":"Persistent chlamydiae: from cell culture to a paradigm for chlamydial pathogenesis","volume":"58","author":"Beatty","year":"1994","journal-title":"Microbiol. Rev."},{"key":"ref4","doi-asserted-by":"publisher","first-page":"15971","DOI":"10.1073\/pnas.2535394100","article-title":"Transcriptome analysis of chlamydial growth during IFN-gamma-mediated persistence and reactivation","volume":"100","author":"Belland","year":"2003","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"ref5","doi-asserted-by":"publisher","first-page":"17","DOI":"10.3389\/fcimb.2014.00017","article-title":"Chlamydia exploit the mammalian tryptophan-depletion defense strategy as a counter-defensive cue to trigger a survival state of persistence","volume":"4","author":"Bonner","year":"2014","journal-title":"Front. Cell. Infect. Microbiol."},{"key":"ref6","doi-asserted-by":"publisher","first-page":"e00184","DOI":"10.1128\/mSystems.00184-17","article-title":"Genomewide transcriptional responses of iron-starved Chlamydia trachomatis reveal prioritization of metabolic precursor synthesis over protein translation","author":"Brinkworth","year":"2018","journal-title":"mSystems"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"e0068520","DOI":"10.1128\/IAI.00685-20","article-title":"Persistence alters the interaction between Chlamydia trachomatis and its host cell","volume":"89","author":"Brockett","year":"2021","journal-title":"Infect. Immun."},{"key":"ref8","doi-asserted-by":"publisher","first-page":"e00630","DOI":"10.1128\/JB.00630-20","article-title":"Genome copy number regulates inclusion expansion, septation, and infectious developmental form conversion in Chlamydia trachomatis","volume":"203","author":"Brothwell","year":"2021","journal-title":"J. Bacteriol."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"1300","DOI":"10.1016\/j.cell.2014.11.017","article-title":"Beta-lactam antibiotics induce a lethal malfunctioning of the bacterial cell wall synthesis machinery","volume":"159","author":"Cho","year":"2014","journal-title":"Cell"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"12588","DOI":"10.1038\/s41598-020-69397-x","article-title":"Penicillin-binding proteins regulate multiple steps in the polarized cell division process of Chlamydia","volume":"10","author":"Cox","year":"2020","journal-title":"Sci. Rep."},{"key":"ref11","doi-asserted-by":"publisher","first-page":"8","DOI":"10.1111\/j.1749-6632.2012.06818.x","article-title":"The physiology of bacterial cell division","volume":"1277","author":"Egan","year":"2013","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref12","doi-asserted-by":"publisher","first-page":"385","DOI":"10.1038\/nrmicro.2016.30","article-title":"Chlamydia cell biology and pathogenesis","volume":"14","author":"Elwell","year":"2016","journal-title":"Nat. Rev. Microbiol."},{"key":"ref13","first-page":"395","article-title":"The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis","volume":"58","author":"Falcieri","year":"1979","journal-title":"Boll. Ist. Sieroter. Milan."},{"key":"ref14","doi-asserted-by":"publisher","first-page":"7144","DOI":"10.1073\/pnas.86.18.7144","article-title":"Interferon gamma-resistant mutants are defective in the induction of indoleamine 2,3-dioxygenase","volume":"86","author":"Feng","year":"1989","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"ref15","doi-asserted-by":"publisher","first-page":"835","DOI":"10.1128\/iai.58.3.835-837.1990","article-title":"Muramic acid is not detectable in Chlamydia psittaci or Chlamydia trachomatis by gas chromatography-mass spectrometry","volume":"58","author":"Fox","year":"1990","journal-title":"Infect. Immun."},{"key":"ref16","doi-asserted-by":"publisher","first-page":"1493","DOI":"10.1099\/13500872-141-7-1493","article-title":"The planctomycetes: emerging models for microbial ecology, evolution and cell biology","volume":"141","author":"Fuerst","year":"1995","journal-title":"Microbiology"},{"key":"ref17","doi-asserted-by":"publisher","first-page":"315","DOI":"10.1099\/00221287-80-1-315","article-title":"A search for the bacterial mucopeptide component, muramic acid, in Chlamydia","volume":"80","author":"Garrett","year":"1974","journal-title":"J. Gen. Microbiol."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"575","DOI":"10.1084\/jem.100.6.575","article-title":"Intracellular forms of meningopneumonitis virus","volume":"100","author":"Gaylord","year":"1954","journal-title":"J. Exp. Med."},{"key":"ref19","doi-asserted-by":"publisher","first-page":"264","DOI":"10.1093\/infdis\/87.3.264","article-title":"The effect of antibiotics on agents of the psittacosis-lymphogranuloma group","volume":"87","author":"Gogolak","year":"1950","journal-title":"J. Infect. Dis."},{"key":"ref20","doi-asserted-by":"publisher","first-page":"e07118","DOI":"10.7554\/eLife.07118","article-title":"Coordination of peptidoglycan synthesis and outer membrane constriction during Escherichia coli cell division","volume":"4","author":"Gray","year":"2015","journal-title":"elife"},{"key":"ref21","doi-asserted-by":"publisher","first-page":"964","DOI":"10.1002\/j.1460-2075.1996.tb00433.x","article-title":"Chlamydia trachomatis interrupts an exocytic pathway to acquire endogenously synthesized sphingomyelin in transit from the Golgi apparatus to the plasma membrane","volume":"15","author":"Hackstadt","year":"1996","journal-title":"EMBO J."},{"key":"ref22","doi-asserted-by":"publisher","first-page":"1457","DOI":"10.1128\/IAI.68.3.1457-1464.2000","article-title":"Chlamydial development is adversely affected by minor changes in amino acid supply, blood plasma amino acid levels, and glucose deprivation","volume":"68","author":"Harper","year":"2000","journal-title":"Infect. Immun."},{"key":"ref23","doi-asserted-by":"publisher","first-page":"297","DOI":"10.1111\/j.1476-5381.1953.tb00798.x","article-title":"The therapy of experimental psittacosis and lymphogranuloma venereum (inguinale) II. The activity of quinoxaline-1:4-dioxide and substituted and related compounds, with a note on the morphological changes induced in lymphogranuloma virus by these compounds and by antibiotics","volume":"8","author":"Hurst","year":"1953","journal-title":"Br. J. Pharmacol. Chemother."},{"key":"ref24","doi-asserted-by":"publisher","first-page":"11430","DOI":"10.1073\/pnas.0703218104","article-title":"Mechanisms of host cell exit by the intracellular bacterium Chlamydia","volume":"104","author":"Hybiske","year":"2007","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"ref25","doi-asserted-by":"publisher","first-page":"3578","DOI":"10.1038\/ncomms4578","article-title":"Cell wall precursors are required to organize the chlamydial division septum","volume":"5","author":"Jacquier","year":"2014","journal-title":"Nat. Commun."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"e1010","DOI":"10.1016\/j.cell.2018.01.021","article-title":"Lysozyme counteracts beta-lactam antibiotics by promoting the emergence of L-form bacteria","volume":"172","author":"Kawai","year":"2018","journal-title":"Cell"},{"key":"ref28","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1111\/mmi.12855","article-title":"Chlamydia trachomatis protein CT009 is a structural and functional homolog to the key morphogenesis component RodZ and interacts with division septal plane localized MreB","volume":"95","author":"Kemege","year":"2015","journal-title":"Mol. Microbiol."},{"key":"ref29","doi-asserted-by":"publisher","first-page":"2745","DOI":"10.1021\/acschembio.9b00664","article-title":"Mechanisms of incorporation for D-amino acid probes that target peptidoglycan biosynthesis","volume":"14","author":"Kuru","year":"2019","journal-title":"ACS Chem. Biol."},{"key":"ref30","doi-asserted-by":"publisher","first-page":"2573","DOI":"10.1099\/mic.0.29032-0","article-title":"The effect of penicillin on Chlamydia trachomatis DNA replication","volume":"152","author":"Lambden","year":"2006","journal-title":"Microbiology"},{"key":"ref31","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1038\/s41467-017-02432-0","article-title":"Replication-dependent size reduction precedes differentiation in Chlamydia trachomatis","volume":"9","author":"Lee","year":"2018","journal-title":"Nat. Commun."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"4","DOI":"10.1186\/1471-2121-10-4","article-title":"The cell cycle of the planctomycete Gemmata obscuriglobus with respect to cell compartmentalization","volume":"10","author":"Lee","year":"2009","journal-title":"BMC Cell Biol."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"71","DOI":"10.3389\/fcimb.2014.00071","article-title":"Morphologic and molecular evaluation of Chlamydia trachomatis growth in human endocervix reveals distinct growth patterns","volume":"4","author":"Lewis","year":"2014","journal-title":"Front. Cell. Infect. Microbiol."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"507","DOI":"10.1038\/nature12892","article-title":"A new metabolic cell-wall labelling method reveals peptidoglycan in Chlamydia trachomatis","volume":"506","author":"Liechti","year":"2014","journal-title":"Nature"},{"key":"ref35","doi-asserted-by":"publisher","first-page":"e1005590","DOI":"10.1371\/journal.ppat.1005590","article-title":"Pathogenic Chlamydia lack a classical Sacculus but synthesize a narrow, mid-cell peptidoglycan ring, regulated by MreB, for cell division","volume":"12","author":"Liechti","year":"2016","journal-title":"PLoS Pathog."},{"key":"ref36","doi-asserted-by":"publisher","first-page":"372","DOI":"10.1093\/infdis\/116.3.372","article-title":"Patterns of response to sulfadiazine, D-cycloserine and D-alanine in members of the psittacosis group","volume":"116","author":"Lin","year":"1966","journal-title":"J. Infect. Dis."},{"key":"ref37","doi-asserted-by":"publisher","first-page":"634","DOI":"10.1038\/nature19331","article-title":"SEDS proteins are a widespread family of bacterial cell wall polymerases","volume":"537","author":"Meeske","year":"2016","journal-title":"Nature"},{"key":"ref38","doi-asserted-by":"publisher","first-page":"e04629","DOI":"10.7554\/eLife.04629","article-title":"General principles for the formation and proliferation of a wall-free (L-form) state in bacteria","volume":"3","author":"Mercier","year":"2014","journal-title":"elife"},{"key":"ref39","first-page":"87","article-title":"Why is Chlamydia sensitive to penicillin in the absence of peptidoglycan?","volume":"2","author":"Moulder","year":"1993","journal-title":"Infect. Agents Dis."},{"key":"ref40","doi-asserted-by":"publisher","first-page":"707","DOI":"10.1128\/jb.85.3.707-711.1963","article-title":"Inhibition of the growth of agents of the psittacosis group by D-Cycloserine and its specific reversal by D-alanine","volume":"85","author":"Moulder","year":"1963","journal-title":"J. Bacteriol."},{"key":"ref41","doi-asserted-by":"publisher","first-page":"164","DOI":"10.1111\/j.1365-2958.2012.08100.x","article-title":"Chlamydia co-opts the rod shape-determining proteins MreB and Pbp2 for cell division","volume":"85","author":"Ouellette","year":"2012","journal-title":"Mol. Microbiol."},{"key":"ref42","doi-asserted-by":"publisher","first-page":"e00252","DOI":"10.1128\/JB.00252-20","article-title":"Division without binary fission: cell division in the FtsZ-less Chlamydia","volume":"202","author":"Ouellette","year":"2020","journal-title":"J. Bacteriol."},{"key":"ref43","doi-asserted-by":"publisher","first-page":"279","DOI":"10.3389\/fmicb.2014.00279","article-title":"Analysis of MreB interactors in Chlamydia reveals a RodZ homolog but fails to detect an interaction with MraY","volume":"5","author":"Ouellette","year":"2014","journal-title":"Front. Microbiol."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"11660","DOI":"10.1073\/pnas.1514026112","article-title":"Structural characterization of muropeptides from Chlamydia trachomatis peptidoglycan by mass spectrometry resolves \u201cchlamydial anomaly\u201d","volume":"112","author":"Packiam","year":"2015","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"ref45","doi-asserted-by":"publisher","first-page":"3101","DOI":"10.3389\/fmicb.2018.03101","article-title":"Chlamydia persistence: a survival strategy to evade antimicrobial effects in-vitro and in-vivo","volume":"9","author":"Panzetta","year":"2018","journal-title":"Front. Microbiol."},{"key":"ref46","doi-asserted-by":"publisher","first-page":"244","DOI":"10.1016\/S0022-5320(84)90122-9","article-title":"Ultrastructure of Chlamydia trachomatis infection of the mouse oviduct","volume":"88","author":"Phillips","year":"1984","journal-title":"J. Ultrastruct. Res."},{"key":"ref47","doi-asserted-by":"publisher","first-page":"2856","DOI":"10.1038\/ncomms3856","article-title":"Discovery of chlamydial peptidoglycan reveals bacteria with murein sacculi but without FtsZ","volume":"4","author":"Pilhofer","year":"2013","journal-title":"Nat. Commun."},{"key":"ref48","doi-asserted-by":"publisher","first-page":"e03222","DOI":"10.1128\/mBio.03222-19","article-title":"Chlamydial MreB directs cell division and peptidoglycan synthesis in Escherichia coli in the absence of FtsZ activity","volume":"11","author":"Ranjit","year":"2020","journal-title":"mBio"},{"key":"ref49","doi-asserted-by":"publisher","first-page":"e1001565","DOI":"10.1371\/journal.pbio.1001565","article-title":"Three-dimensional reconstruction of bacteria with a complex endomembrane system","volume":"11","author":"Santarella-Mellwig","year":"2013","journal-title":"PLoS Biol."},{"key":"ref50","doi-asserted-by":"publisher","first-page":"e2104686118","DOI":"10.1073\/pnas.2104686118","article-title":"Starvation induces shrinkage of the bacterial cytoplasm","volume":"118","author":"Shi","year":"2021","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"ref51","doi-asserted-by":"publisher","first-page":"e00086","DOI":"10.1128\/IAI.00086-20","article-title":"Chlamydia trachomatis oligopeptide transporter performs dual functions of oligopeptide transport and peptidoglycan recycling","volume":"88","author":"Singh","year":"2020","journal-title":"Infect. Immun."},{"key":"ref52","doi-asserted-by":"publisher","first-page":"e1008078","DOI":"10.1371\/journal.ppat.1008078","article-title":"Fosmidomycin, an inhibitor of isoprenoid synthesis, induces persistence in Chlamydia by inhibiting peptidoglycan assembly","volume":"15","author":"Slade","year":"2019","journal-title":"PLoS Pathog."},{"key":"ref53","doi-asserted-by":"publisher","first-page":"754","DOI":"10.1126\/science.282.5389.754","article-title":"Genome sequence of an obligate intracellular pathogen of humans: Chlamydia trachomatis","volume":"282","author":"Stephens","year":"1998","journal-title":"Science"},{"key":"ref54","doi-asserted-by":"publisher","first-page":"678","DOI":"10.1093\/infdis\/131.6.678","article-title":"Light and electron microscopic study of Chlamydia trachomatis infection of the uterine cervix","volume":"131","author":"Swanson","year":"1975","journal-title":"J. Infect. Dis."},{"key":"ref55","doi-asserted-by":"publisher","first-page":"587","DOI":"10.1038\/s41564-018-0345-x","article-title":"FtsW is a peptidoglycan polymerase that is functional only in complex with its cognate penicillin-binding protein","volume":"4","author":"Taguchi","year":"2019","journal-title":"Nat. Microbiol."},{"key":"ref56","doi-asserted-by":"publisher","first-page":"1184","DOI":"10.1128\/jb.94.4.1184-1188.1967","article-title":"Preparation and chemical composition of the cell membranes of developmental reticulate forms of meningopneumonitis organisms","volume":"94","author":"Tamura","year":"1967","journal-title":"J. Bacteriol."},{"key":"ref57","doi-asserted-by":"publisher","first-page":"408","DOI":"10.1128\/jb.114.1.408-412.1973","article-title":"Miniature cell formation in Chlamydia psittaci","volume":"114","author":"Tanami","year":"1973","journal-title":"J. Bacteriol."},{"key":"ref58","doi-asserted-by":"publisher","first-page":"1757.e5","DOI":"10.1016\/j.cub.2017.05.076","article-title":"Fatty acid availability sets cell envelope capacity and dictates microbial cell size","volume":"27","author":"Vadia","year":"2017","journal-title":"Curr. Biol."},{"key":"ref59","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1093\/infdis\/87.3.249","article-title":"The effect of antibiotics on agents of the psittacosis-lymphogranuloma group. I. The effect of penicillin","volume":"87","author":"Weiss","year":"1950","journal-title":"J. Infect. Dis."},{"key":"ref60","doi-asserted-by":"publisher","first-page":"1047","DOI":"10.1111\/j.1462-5822.2006.00686.x","article-title":"Stimulation of the cytosolic receptor for peptidoglycan, Nod1, by infection with Chlamydia trachomatis or Chlamydia muridarum","volume":"8","author":"Welter-Stahl","year":"2006","journal-title":"Cell. Microbiol."},{"key":"ref61","doi-asserted-by":"publisher","first-page":"2379","DOI":"10.1128\/IAI.68.4.2379-2385.2000","article-title":"Ultrastructural analysis of developmental events in Chlamydia pneumoniae-infected cells","volume":"68","author":"Wolf","year":"2000","journal-title":"Infect. Immun."},{"key":"ref62","doi-asserted-by":"publisher","first-page":"88","DOI":"10.1086\/652394","article-title":"Chlamydia trachomatis persistence in vitro: an overview","volume":"201","author":"Wyrick","year":"2010","journal-title":"J. Infect. Dis."}],"container-title":["Frontiers in Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2021.733850\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,12,9]],"date-time":"2021-12-09T10:53:42Z","timestamp":1639047222000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2021.733850\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,9]]},"references-count":61,"alternative-id":["10.3389\/fmicb.2021.733850"],"URL":"https:\/\/doi.org\/10.3389\/fmicb.2021.733850","relation":{},"ISSN":["1664-302X"],"issn-type":[{"value":"1664-302X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,9]]},"article-number":"733850"}}