f_2_nh4_medium (CultureMech:000169)

Overview

External ontology

UTEX:f-2-nh4-medium (source link unavailable) — F/2 + NH4 Medium

Applications

Algae cultivation
Phytoplankton culture
Microalgae research

Notes

UTEX prepares F/2 + NH4 Medium by dispensing prepared F/2 Medium into 175 mL portions and adding a pinch of NH4MgPO4 to each flask.

Composition

flowchart LR
    CultureMech_000169["f_2_nh4_medium"]
    ing0_NH4MgPO4["NH4MgPO4"]
    CultureMech_000169 --> ing0_NH4MgPO4
    CHEBI_149425["CHEBI:149425"]
    ing0_NH4MgPO4 -.-> CHEBI_149425

Ingredients (1)

#	Ingredient	Concentration	Ontology	Notes
1	NH4MgPO4 H4N.Mg.O4P 137.314 g/mol Sigma 529354		CHEBI:149425 ammonium magnesium phosphate	Add a pinch of NH4MgPO4 to each 175 mL aliquot of prepared F/2 in a 250 mL flask. Pinch mass and final concentration are not quantified.

Preparation

Prepare F/2 Medium.
Dispense 175 mL into 250 mL flasks.
Add a pinch of NH4MgPO4 to each flask.

Solutions

F/2 Medium

Dose: 0.175 L

CultureMech:000170

Use 175 mL prepared F/2 per 250 mL flask before adding the unquantified supplement. The 0.175 L value is an absolute aliquot volume, not a per-liter concentration.

Target organisms

No target organisms are recorded.

Provenance

Timestamp	Curator	Action	Notes
2026-01-28T00:00:00+00:00	utex-import	Imported from UTEX Culture Collection	Source ID: f-2-nh4-medium, URL: https://utex.org/products/f-2-nh4-medium
2026-03-13T06:18:53.390357Z	culturemech-id-assigner-v1.0	Assigned CultureMech ID	Assigned stable identifier: CultureMech:000169
2026-03-17T19:45:04.328574+00:00	normalize_media_names_to_snake_case.py	NAME_NORMALIZED	Normalized name from "F/2 + NH4 Medium" to "f_2_nh4_medium" for consistent matching
2026-05-16T09:02:56.553737+00:00	migrate_legacy_fields.py	MIGRATED_LEGACY_FIELDS	curation_history.date->timestamp=1; references.reference_id->reference=2; category->lowercase=1
2026-05-16T09:11:01.668161+00:00	migrate_preparation_steps.py	MIGRATED_PREPARATION_STEPS	instruction->action+description for 9 step(s)
2026-08-30T00:58:31.626096+00:00	repair_utex_ingredients.py	REPAIRED_UTEX_COMPOSITION	Restored 2 ingredient name(s) and amount(s) from a re-fetched UTEX capture. The original fetcher read fixed column positions, so the row ordinal was stored as the ingredient name, the component name as the amount, and the Amount column was never read; concentration was then filled in as G_PER_L regardless. Source: https://utex.org/pages/algal-culture-media, captured 2026-08-29T17:46:40.207779.
2026-09-06T00:00:00-07:00	repair_utex_remaining_score50.py	RESOLVED_UTEX_SCORE50_ALGAE_GRAPH	UTEX prepares F/2 + NH4 Medium by dispensing prepared F/2 Medium into 175 mL portions and adding a pinch of NH4MgPO4 to each flask.
2026-10-10T00:39:00.252028+00:00	codex	CURATED_UTEX_F2_INGREDIENT_AND_STOCK_STAGE_EVIDENCE	Trace-metal source mass/molarity discrepancy remains unresolved; only mass-column stock amounts are supported. The parent and 1% HTML/PDF seawater salinity versions differ; neither is silently substituted for the other. The 5% source lists vitamin doses but omits a later vitamin-addition step; no missing procedure is invented. Narrative literature variants and existing organism/growth claims are unchanged and not certified by UTEX sources. No numeric amount is invented for makeup/carrier water, seawater or the NH4MgPO4 pinch.
2026-10-10T02:50:18.663542+00:00	codex	CURATED_F2_VARIANT_FORMULATION_AND_NH4_RELATIONSHIP_EVIDENCE	The selenite correction reports Table S1 only: 0.001 micromolar = 1 nanomolar. Main methods remain inaccessible, so possible main-text/table disagreement and the existing UTEX LB2658 strain claim are not resolved. The Table S1 recipe and Matsui artificial-seawater variant are not equivalent to canonical UTEX natural-seawater F/2; no parent ingredient or stock concentration changes. The Tetraselmis evidence is abstract-level only. Phosphorus repletion is a separate experimental condition, not an added ingredient in the nitrogen-replete variant. The NH4MgPO4 pinch remains unquantified; 250 mL is flask capacity, not final medium volume. Earlier UTEX stock molarity, salinity-version, chemical catalog and missing vitamin-step issues remain open. Existing organism/growth claims and earlier curation history are unchanged. Matsui methods were manually inspected, not captured as a complete HTTP download; current browser-check failures and production reference outcomes are reported separately.