The medium is the experiment, and the guess fails twice (#183, #543)

kb/communities/Suillus_Bacillus_Thiamine_Ectomycorrhizal_SynCom.yaml

@@ -326,6 +326,43 @@ growth_media:
       at 28°C in the dark
     explanation: Plate format, plug size, temperature and light regime for the assay.
 
+cultivation_setup:
+- cultivation_mode: BATCH
+  operating_temperature: 28.0
+  operating_temperature_unit: °C
+  instrument_detail: >-
+    The fungus as an 8 mm plug and B. altitudinis B4 at 50 μL of OD600 0.4, co-cultured in
+    P20 liquid medium made without thiamine, alongside single-partner treatments as controls.
+    Plate work ran at 28 °C in the dark.
+  notes: >-
+    The medium is the experiment. P20 without thiamine is what makes S. clintonianus - a
+    thiamine auxotroph - dependent on the bacterium, so recording the medium without the
+    omission would describe a system in which the interaction cannot be observed. This is the
+    same shape as the fumarate deliberately excluded from the syntrophy record: a single
+    component decides whether the partnership is necessary.
+
+    No `system_type` or `working_volume`: the source gives neither for the co-culture, and
+    both the liquid co-culture and the 60 mm plate assays appear, so one vessel value would
+    misdescribe half the work.
+
+    Predicted a likely refusal in #543 on the assumption that a plant-associated SynCom lives
+    on the plant. Wrong again, and differently: the two partners are co-cultured in liquid,
+    with the plant absent. Second of the five in that group to fail, which is why the
+    remaining three are not being classified without reading.
+  evidence:
+  - reference: PMID:41454778
+    supports: SUPPORT
+    evidence_source: IN_VITRO
+    snippet: clintonianus (8 mm) and B. altitudinis B4 (50 μL, OD600 = 0.4) were co-cultured in
+      P20 liquid medium (without thiamine)
+    explanation: The two members were grown together, in a medium lacking the vitamin at issue.
+  - reference: PMID:41454778
+    supports: SUPPORT
+    evidence_source: IN_VITRO
+    snippet: Fungal plugs (8 mm) were placed in the center of the plate (60 mm) and incubated at
+      28°C in the dark
+    explanation: Temperature and light regime for the plate assays.
+
 environmental_factors:
 - name: Thiamine limitation of the fungal partner
   value: fungus cannot effectively obtain or synthesize thiamine