TraitMech

TraitMech › MORPHOLOGY

ovoid shaped

METPO:1000677 · CLASS · REVIEWED

A cell shape in which an organism has an oval morphology, rounded at both ends with one end often slightly broader than the other.

Ovoid-shape midcell peptidoglycan mechanism

Evidence-backed causal sketch linking ovoid morphology to midcell peptidoglycan assembly, MapZ division-site placement, DivIVA-associated growth, and rounded ovoid geometry.

Ovoid-shape midcell peptidoglycan mechanism Interactive directed graph showing evidence-backed causal relationships for ovoid shaped.

Edge evidence

  • MapZ positions midcell peptidoglycan assembly

    MapZ participates in division-site placement for ovoid growth.

    • DOI:10.1016/j.mib.2016.07.014 relies on the membrane protein MapZ Supports MapZ as a division-positioning factor in S. pneumoniae.
  • midcell peptidoglycan assembly causes ovoid geometry biolink:causes

    Midcell peptidoglycan assembly shapes ovoid cell geometry.

    • DOI:10.1016/j.cub.2021.04.041 peptidoglycan synthesis ... in the ovoid bacterium Supports PG assembly dynamics in ovoid S. pneumoniae.
  • DivIVA controls septum splitting RO:0002211

    DivIVA controls septum splitting and elongation dynamics.

    • DOI:10.1128/mbio.01311-24 DivIVA controls the dynamics of septum splitting and cell elongation Supports DivIVA in ovococcal cell morphogenesis.
  • septum splitting contributes to ovoid geometry RO:0002326

    Septum splitting and elongation dynamics contribute to ovoid morphology.

    • DOI:10.1128/mbio.01311-24 how ovoid bacteria proliferate Supports septum/elongation dynamics as relevant to ovoid bacterial proliferation.
  • ovoid geometry manifests as ovoid shaped METPO:2007400

    Ovoid cell-body geometry manifests the ovoid-shaped trait.

    • DOI:10.1016/j.cub.2021.04.041 ovoid-shaped bacteria Supports the trait endpoint.
  • midcell peptidoglycan assembly has component septal peptidoglycan synthesis

    Ovococcal midcell growth includes a distinct septal PG synthesis mode.

    • DOI:10.1042/BSR20221664 There are two spatially distinct modes of PG synthesis: septal and peripheral.
  • midcell peptidoglycan assembly has component peripheral peptidoglycan synthesis

    Ovococcal midcell growth includes a distinct peripheral PG synthesis mode.

    • DOI:10.1042/BSR20221664 There are two spatially distinct modes of PG synthesis: septal and peripheral.
  • FtsZ treadmilling drives septal peptidoglycan synthesis

    FtsZ treadmilling drives septal PG synthesis.

    • DOI:10.1042/BSR20221664 FtsZ treadmilling drives septal PG synthesis together with the FtsW-PBP2x complex.
  • FtsW-PBP2x complex synthesizes septal peptidoglycan synthesis

    The FtsW-PBP2x complex synthesizes the division septum.

    • DOI:10.1042/BSR20221664 Septal PG synthesis is driven by the FtsW-PBP2x complex to synthesize the division septum.
  • RodA-PBP2b elongasome drives peripheral peptidoglycan synthesis

    The RodA-PBP2b elongasome drives peripheral PG synthesis.

    • DOI:10.1042/BSR20221664 Peripheral (elongation) activity is carried out by the elongasome, driven by the RodA-PBP2b pair.
  • MapZ positions FtsZ ring

    MapZ guides movement and positioning of the FtsZ ring.

    • DOI:10.1042/BSR20221664 MapZ guides movement of FtsZ and associated proteins from the septal ring to the equatorial ring.
  • midcell peptidoglycan assembly assembles as concentric midcell rings

    Septal and peripheral PG machineries assemble at midcell into concentric rings.

    • DOI:10.1042/BSR20221664 Septal and peripheral PG-synthesis machineries assemble at mid-cell into concentric rings (inner septal, outer peripheral).

Provenance

Source
METPO (2025-11-25)
Author
Luke Wang
Definition source
DOI:10.1016/j.cub.2021.04.041

Parent traits (1)

Synonyms (2)

  • S_ovoid RELATED_SYNONYM · metpo.owl
  • ovoid-shaped RELATED_SYNONYM · metpo.owl

kg-microbe context

Matched 1 kg-microbe node via direct_metpo.

  • METPO:1000677 [+1.410, -5.519, -0.585, +0.196, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Deep research

Generated by just research-trait; source: research/traits/morphology/ovoid_shaped-deep-research-falcon.md

Unreviewed literature output — not curated TraitMech content Ontology identifiers suggested below have not been resolved against their ontologies, and some are known to be wrong. Check any CURIE against the source before using it. 
# Curation report: ovoid-shaped microbial cells

## Trait record and scope

- **Trait:** ovoid shaped
- **Identifier:** **METPO:1000677**
- **Category / kind:** MORPHOLOGY / CLASS
- **Reviewed definition:** an oval cell morphology rounded at both ends, often with one end slightly broader.
- **Parent:** METPO:1000666
- **Synonyms:** *S_ovoid*, *ovoid-shaped*
- **Best-supported mechanistic model:** *Streptococcus pneumoniae* (pneumococcus; an “ovococcus”).

For causal-graph purposes, the trait should represent an **individual-cell shape**, not cell chaining, colony morphology, capsule appearance, or an environmental preference. In pneumococcus, the mature cell is described as a **prolate ellipsoid/rugby-ball shape**, conveniently expressible by an elliptic ratio, length/diameter (E = L/D). The morphology is generated by balanced **septal** and **peripheral** peptidoglycan (PG) synthesis at midcell. It is therefore a continuously produced morphogenetic state rather than a static structural attribute. (trouve2021nanoscaledynamicsof pages 7-9, stamsas2020acozehomolog pages 1-2)

### Boundaries

1. **Versus spherical cocci:** near-spherical cells have little or insufficient longitudinal extension. In pneumococcus, depletion of the peripheral-growth factors PBP2b, MreC, or MreD produces rounded/spherical cells, providing an operational boundary between ovoid and spherical morphologies. (xiang2019regulationofcell pages 24-30)
2. **Versus rods:** rods generally use MreB-guided, dispersed lateral-wall insertion. Pneumococcus lacks MreB and instead performs zonal elongation in a restricted annulus around midcell. Thus, an elongated cell caused by blocked septation is not necessarily a normal rod-shaped phenotype. (trouve2021nanoscaledynamicsof pages 1-3, fenton2016cozeisa pages 2-4)
3. **Versus diplococcal/chained arrangements:** diplococci and chains describe cell arrangement, not the shape of each cell. Chaining frequently accompanies morphogenesis defects but should be represented separately.
4. **Versus “lentil,” pointed, or minicell phenotypes:** these are abnormal shape outcomes caused by perturbing PG assembly or division-site placement and should not be treated as synonyms of ovoid.
5. **Taxonomic boundary:** the detailed graph below is principally a pneumococcal mechanism. “Ovoid shaped” occurs in other microbes, but homology of shape does not establish homology of mechanism.

## Current mechanistic understanding

Pneumococcus coordinates two PG-synthesis systems in the same nanoscale midcell zone. The **elongasome** supports peripheral PG synthesis and longitudinal extension; the **divisome** synthesizes septal PG and drives constriction. Both initially occupy one annular region and subsequently resolve into concentric zones. Elongation can continue after septation is complete. (trouve2021nanoscaledynamicsof pages 1-3)

The central current model adds PG hydrolysis to this synthesis-only description. Septal PG is produced from early in the cycle but is promptly cleaved; peripheral machinery inserts material into or around the remodeled layers. A visible septum develops when centripetal septal synthesis outpaces cleavage. Ovoid morphology therefore emerges from the relative rates and spatial displacement of septal synthesis, peripheral synthesis, and PG cleavage—not from two cleanly separated, sequential growth phases. (trouve2021nanoscaledynamicsof pages 10-11)

FtsZ supplies the common spatial organizer in this MreB-lacking bacterium. PBP2x–FtsW is associated with septal synthesis, whereas PBP2b–RodA and associated MreC/MreD/RodZ proteins support peripheral synthesis. PBP1a provides additional glycosyltransferase/transpeptidase activity whose localization and activation are controlled by proteins including CozE and, according to recent work, GarP and the pneumococcal S protein. (trouve2021nanoscaledynamicsof pages 1-3, stamsas2020acozehomolog pages 1-2, briggs2021thepneumococcaldivisome pages 6-7, millat2024characterizationofa pages 9-12, burnier2024abacterialcell pages 1-4)

## Candidate nodes grouped by type

### Phenotypes and processes

- **ovoid shaped — METPO:1000677**
- prolate-ellipsoid cell morphology — label-only candidate
- cell elongation — **GO:0051301** may be inappropriate because that term is cell division; retain label-only pending ontology review
- cell division — **GO:0051301**
- peptidoglycan biosynthetic process — **GO:0009252**
- septal peptidoglycan synthesis — label-only candidate
- peripheral peptidoglycan synthesis — label-only candidate
- septum formation/constriction — label-only candidate
- septum splitting — label-only candidate
- PG cleavage/remodeling — label-only candidate
- division-site/Z-ring positioning — label-only candidate
- cell-size homeostasis — label-only candidate
- protein phosphorylation — **GO:0006468**

### Cellular structures and locations

- midcell
- equatorial ring / PG assembly annulus
- FtsZ ring (Z-ring)
- division septum
- leading edge of invaginating septum
- peripheral/outer PG synthesis ring
- divisome complex
- elongasome complex
- cytoplasmic membrane
- peptidoglycan-containing cell wall

Showing the first 60 of 231 lines of findings; the linked file also carries the run's front matter and the prompt it was given — read the full report.

Curation history

  1. · SEEDED_FROM_METPO · seed_from_metpo

    imported from data/raw/metpo.owl (CLASS)

  2. · CURATED_WITH_LITERATURE · codex

    Added DOI-backed definition and causal graph for MapZ, DivIVA, midcell peptidoglycan assembly, septum splitting, and ovoid cell geometry.

  3. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002326×1).

  4. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002211×1, METPO:2007400×1).

  5. · RENAME_PREDICATE_LABELS · claude

    Renamed 1 causal-edge predicate label(s) to align with existing groundings: shapes → causes ×1.

  6. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (biolink:causes×1).

  7. · GROUND_CAUSAL_NODES · claude

    Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:Q1IYG2×1).

  8. · ENRICH_CAUSAL_GRAPH · claude

    Added 7 evidence-backed generic edges (7 new nodes) from the deep-research report.