Parasites

Overview

This project is a broad umbrella for gene reviews of parasitic and
host-associated organisms — species whose biology is defined by a parasitic
(or otherwise intimate host-exploiting) lifestyle. It collects the gene biology
that is specific to parasitism: host invasion, host-immune evasion/modulation,
nutrient acquisition from the host, and the molecular machinery of the
parasite–host (and parasite–symbiont) interface.

It serves as a hub that ties together more focused parasite-related efforts
rather than duplicating them — see Related projects.

Scope

• Animal-parasitic and insect-parasitic nematodes, including
  entomopathogenic nematodes (EPNs) such as Steinernema, which kill insect
  hosts in mutualistic partnership with Xenorhabdus/Photorhabdus bacteria.
• Other metazoan and protozoan parasites as gene reviews accrue
  (helminths, apicomplexans, etc.).
• Host-modulating secreted proteins of parasites and blood-feeders —
  these are the subject of the existing
  PARASITE_IMMUNE_MODULATORS project, treated
  here as a sub-topic.

A note on boundaries: not every host-associated nematode is a parasite.
Necromenic associates (e.g. Pristionchus pacificus, which rides live beetles
but only feeds after they die) and free-living comparators (e.g.
Caenorhabditis briggsae) are not parasites and are tracked under
SATELLITE_MODEL_ORGANISMS. True insect-parasitic
nematodes that are also used as comparative models are cross-listed.

Species in scope

Species	Parasitic lifestyle	In repo?	Notes
Steinernema carpocapsae	Entomopathogenic (insect-parasitic) nematode	✅ genes/STECR/nas-8	Best-annotated EPN. UniProt code STECR, NCBITaxon:34508. Holds the genus's only reviewed (Swiss-Prot) entry: D2KBH9 (NAS8_STECR), a secreted astacin metalloprotease — the parasitism-relevant anchor seed.
Steinernema hermaphroditum	Entomopathogenic (insect-parasitic) nematode	❌ not yet	Mutualist of Xenorhabdus; emerging genetic model for EPN/symbiosis biology. UniProt code 9BILA (provisional, auto-assigned), NCBITaxon:289476 → genes/9BILA/. No reviewed entries.
Brugia malayi	Filarial (human lymphatic filariasis), mosquito-borne	✅ 5 genes seeded (see below)	Model filarial nematode, UniProt code BRUMA, NCBITaxon:6279. The reviewed-rich anchor for the project (68 Swiss-Prot entries) — provides experimentally-characterized host-interaction/immune-evasion proteins to review.

The EPNs most biologically aligned with Steinernema (Heterorhabditis
bacteriophora, HETBA) and Strongyloides ratti (STRRB) have 0 reviewed
entries, so B. malayi was chosen as the reviewed-rich nematode anchor.
Additional parasites (other filariae — Onchocerca volvulus ONCVO 43,
Ascaris suum ASCSU 67 — parasitic helminths, protozoan parasites) to be added
as reviews are scoped.

Genes for review

• [x] Steinernema carpocapsae STECR nas-8 (D2KBH9, zinc metalloproteinase
  / astacin, EC 3.4.24.21) — seeded into genes/STECR/nas-8/; annotations are
  PENDING review. Secreted protease relevant to host invasion; carries an EXP
  metalloendopeptidase-activity annotation from PMID:20670659 (Sc-AST
  characterization) plus IEA terms.
• [ ] Steinernema hermaphroditum (9BILA, NCBITaxon:289476) — seed gene(s)
  TBD; not yet fetched into the repo. No reviewed entries, so any seed is a
  TrEMBL accession. Candidate areas: infective-juvenile development, host-immune
  evasion, and the Xenorhabdus symbiosis interface.
• BRUMA (B. malayi) host-interaction / immune-evasion set — reviewed,
  protein-level (PE=1) filarial genes; seeded, annotations PENDING:
• [ ] cpi-2 (A0A0K0IP23) — cystatin; secreted immunomodulator (inhibits
  host cysteine proteases / modulates antigen presentation). Has experimental
  annotations.
• [ ] far-1 (Q93142) — fatty-acid & retinol-binding protein (Bm20), a
  classic secreted excretory–secretory immunomodulator. Has experimental
  annotations.
• [ ] dpy-31 (A8Q2D1) — zinc metalloproteinase / astacin (procollagen
  C-proteinase), cuticle biogenesis — parallels the Steinernema nas-8 astacin.
• [ ] gp29 (P67877) — cuticular glutathione peroxidase, major surface
  antigen (oxidative defense at the host interface).
• [ ] mf1 (P29030) — endochitinase (MF1 antigen), microfilarial
  sheath / vaccine candidate.

Status / next steps

• SCOPING. Parasite seeds present: S. carpocapsae nas-8 (EPN anchor) and
  a 5-gene B. malayi host-interaction set (reviewed-rich filarial anchor) — all
  PENDING review.
• Annotation availability (UniProt, 2026-06): across the whole genus
  Steinernema there is exactly 1 reviewed (Swiss-Prot) entry — D2KBH9
  (NAS8_STECR, S. carpocapsae astacin metalloprotease). S. hermaphroditum
  (9BILA) has 0 reviewed entries (~36,000 TrEMBL); S. carpocapsae
  (STECR) has 1 reviewed + ~35,200 TrEMBL.
• Next: complete the PENDING annotation review of S. carpocapsae nas-8
  (start from the EXP PMID:20670659 evidence), then expand to S. hermaphroditum
  TrEMBL genes paired with literature + bioinformatics rather than relying on
  existing GO annotation.
• Pull the PARASITE_IMMUNE_MODULATORS candidate
  list under this umbrella's "host-modulation" sub-topic.

Related projects

• PARASITE_IMMUNE_MODULATORS — parasite/
  blood-feeder secreted proteins that modulate host immunity (sub-topic).
• SATELLITE_MODEL_ORGANISMS — non-parasitic
  comparative nematodes (C. briggsae) and necromenic associates
  (P. pacificus); some insect-parasitic nematodes are cross-listed there.