osmiophilic body

GO:0044310 · Membrane organelle · Membrane bounded organelle · Proposed

A membrane-bounded vesicle found predominantly in Plasmodium female gametocytes, that becomes progressively more abundant as the gametocyte reaches full maturity. These vesicles lie beneath the subpellicular membrane of the gametocyte, and the release of their contents into the parasitophorous vacuole has been postulated to aid in the escape of gametocytes from the erythrocyte after ingestion by the mosquito. [GO:0044310]

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
osmiophilic body membrane	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Membrane boundary of the electron-dense osmiophilic body in mature Plasmodium falciparum female gametocytes. `GO:0044310` GO defines osmiophilic bodies as membrane-bounded vesicles. `DOI:10.1111/j.1365-2958.2007.06039.x` De Koning-Ward et al. 2008 studied membrane-bound osmiophilic bodies in P. falciparum female gametocytes.
Pfg377 osmiophilic body protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	Pfg377		UNKNOWN	Gametocyte protein associated with P. falciparum osmiophilic bodies and required for the normal osmiophilic-body complement of female gametocytes. `DOI:10.1016/0166-6851(95)02491-3` Alano et al. 1995 identified Pfg377 as a P. falciparum gametocyte antigen associated with osmiophilic bodies. `DOI:10.1111/j.1365-2958.2007.06039.x` De Koning-Ward et al. 2008 used targeted gene disruption to tie Pfg377 to normal osmiophilic-body formation.

Taxonomic distribution

NCBITaxon:5833 Plasmodium falciparum — COMMON: Osmiophilic bodies are directly evidenced in mature P. falciparum female gametocytes, where Pfg377 loss reduces the normal organelle complement. [DOI:10.1111/j.1365-2958.2007.06039.x]

Canonical examples

NCBITaxon:5833 Plasmodium falciparum — Human malaria parasite in which Pfg377 disruption connected osmiophilic body formation to female gametocyte emergence and mosquito infectivity. [DOI:10.1111/j.1365-2958.2007.06039.x]

Functions

female gametocyte emergence support — Osmiophilic bodies in mature P. falciparum female gametocytes support efficient emergence from erythrocytes after gametogenesis is induced.
- DOI:10.1111/j.1365-2958.2007.06039.x De Koning-Ward et al. 2008 found that Pfg377-negative female gametocytes lack the full osmiophilic-body complement and are less efficient at emergence from erythrocytes.
mosquito infection support — Normal osmiophilic-body formation contributes to P. falciparum transmission to mosquitoes after a gametocyte-containing blood meal.
- DOI:10.1111/j.1365-2958.2007.06039.x De Koning-Ward et al. 2008 linked the Pfg377-negative osmiophilic-body defect to a strong reduction in mosquito oocyst formation.

Mechanism graphs

Pfg377 supports osmiophilic-body abundance and gametocyte emergence (FUNCTION)

Pfg377 associates with P. falciparum osmiophilic bodies and supports normal osmiophilic-body formation; female gametocytes with a reduced organelle complement emerge from erythrocytes less efficiently and are defective in mosquito infection.

Subject	Predicate	Object	Evidence
osmiophilic body membrane	bounds	osmiophilic body	`GO:0044310` GO defines osmiophilic bodies as membrane-bounded vesicles of Plasmodium female gametocytes.
Pfg377 osmiophilic body protein	associates with	osmiophilic body	`DOI:10.1016/0166-6851(95)02491-3` Alano et al. 1995 identified Pfg377 as a P. falciparum gametocyte antigen associated with osmiophilic bodies.
Pfg377 osmiophilic body protein	supports formation of	osmiophilic body	`DOI:10.1111/j.1365-2958.2007.06039.x` De Koning-Ward et al. 2008 found fewer osmiophilic bodies in Pfg377-negative female gametocytes.
osmiophilic body	supports	female gametocyte emergence	`DOI:10.1111/j.1365-2958.2007.06039.x` De Koning-Ward et al. 2008 connected the Pfg377 osmiophilic-body defect to reduced female gametocyte emergence.
female gametocyte emergence	supports	mosquito oocyst formation	`DOI:10.1111/j.1365-2958.2007.06039.x` De Koning-Ward et al. 2008 found that the reduced emergence of Pfg377-negative gametocytes strongly impaired mosquito oocyst formation.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings for Pfg377 and the osmiophilic body membrane. This first osmiophilic-body record keeps the Pfg377 protein and the vesicle membrane label-only because no exact InterPro, Pfam, NCBIfam, or GO identifier for those source-neutral component classes was verified.
INTERPRETATION (RESOLVED): Avoid asserting a direct osmiophilic-body cargo-release mechanism for female gametocyte egress until direct physical evidence is curated. GO's definition and De Koning-Ward et al. describe release of osmiophilic-body contents into the parasitophorous vacuole as a postulated aid to escape. The graph therefore captures the supported Pfg377-to-organelle and emergence phenotypes without converting that postulate into a causal edge.

Evidence

GO:0044310 Gene Ontology cellular-component term for osmiophilic body.
GO:0031410 Gene Ontology cellular-component parent term for cytoplasmic vesicles.
DOI:10.1016/0166-6851(95)02491-3 Alano et al. 1995, COS cell expression cloning of Pfg377, a Plasmodium falciparum gametocyte antigen associated with osmiophilic bodies, Molecular and Biochemical Parasitology.
DOI:10.1111/j.1365-2958.2007.06039.x De Koning-Ward et al. 2008, The role of osmiophilic bodies and Pfg377 expression in female gametocyte emergence and mosquito infectivity in the human malaria parasite Plasmodium falciparum, Molecular Microbiology.
DOI:10.1074/mcp.m116.060681 Suarez-Cortes et al. 2016, Comparative Proteomics and Functional Analysis Reveal a Role of Plasmodium falciparum Osmiophilic Bodies in Malaria Parasite Transmission, Molecular & Cellular Proteomics.

Curation history

2026-10-03T03:16:45Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-03T03:18:15Z codex · EXPANDED_RECORD — Added cytoplasmic-vesicle parentage, membrane and Pfg377 components, P. falciparum female-gametocyte scope, DOI/GO evidence, a nonmechanistic Pfg377 emergence graph, and component-grounding and release-scope discussions.

Source: data/structures/membrane_organelle/osmiophilic_body.yaml