biostudies-literatureSexton DLGouvernement du Canada | Natural Sciences and Engineering Research Council of Canadae0190621https://www.ebi.ac.uk/biostudies/studies/S-EPMC8788754biostudies-literatureUnknown88(2)Dehalococcoides mccartyi (<i>Dhc</i>) and <i>Dehalogenimonas</i> spp. (<i>Dhgm</i>) are members of the class <i>Dehalococcoidia</i>, phylum Chloroflexi, characterized by streamlined genomes and a strict requirement for organohalogens as electron acceptors. Here, we used cryo-electron tomography to reveal morphological and ultrastructural features of <i>Dhc</i> strain BAV1 and "<i>Candidatus</i> Dehalogenimonas etheniformans" strain GP cells at unprecedented resolution. <i>Dhc</i> cells were irregularly shaped discs (890 ± 110 nm long, 630 ± 110 nm wide, and 130 ± 15 nm thick) with curved and straight sides that intersected at acute angles, whereas <i>Dhgm</i> cells appeared as slightly flattened cocci (760 ± 85 nm). The cell envelopes were composed of a cytoplasmic membrane (CM), a paracryApplied and environmental microbiologyUltrastructure of Organohalide-Respiring <i>Dehalococcoidia</i> Revealed by Cryo-Electron Tomography.PMC878875404345546024Kara Murdoch FTocheva EILoffler FESexton DLChen GHashimi AfalseUltrastructure of Organohalide-Respiring <i>Dehalococcoidia</i> Revealed by Cryo-Electron Tomography.Dehalococcoides mccartyi (<i>Dhc</i>) and <i>Dehalogenimonas</i> spp. (<i>Dhgm</i>) are members of the class <i>Dehalococcoidia</i>, phylum Chloroflexi, characterized by streamlined genomes and a strict requirement for organohalogens as electron acceptors. Here, we used cryo-electron tomography to reveal morphological and ultrastructural features of <i>Dhc</i> strain BAV1 and "<i>Candidatus</i> Dehalogenimonas etheniformans" strain GP cells at unprecedented resolution. <i>Dhc</i> cells were irregularly shaped discs (890 ± 110 nm long, 630 ± 110 nm wide, and 130 ± 15 nm thick) with curved and straight sides that intersected at acute angles, whereas <i>Dhgm</i> cells appeared as slightly flattened cocci (760 ± 85 nm). The cell envelopes were composed of a cytoplasmic membrane (CM), a paracry2022-01-01T00:00:00Z2022 Jan2026-06-07T07:30:49.22Z2025-04-19T10:46:51.699ZS-EPMC87887543478806010.1128/AEM.01906-2110.1128/aem.01906-21