{"id":"06c1b1ac-3a75-5921-94a2-39290227e2e7","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-microbial-cresol","predicate":"produces","statement":"C. difficile fermented tyrosine to p-cresol; a p-cresol-deficient mutant had altered competitive fitness in co-culture and a mouse relapse model.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"49aebce5-2fe5-5d4d-a43f-03c30ce8a1f4","mechanism_event_label":"The same precursor can feed a microbial competition mechanism.","subject":{"id":"0acfd2eb-4ac3-5045-add8-614757981f1f","slug":"c-difficile-tyrosine-fermentation","display_name":"Clostridioides difficile tyrosine fermentation","entity_type_key":"cellular_process"},"object":{"id":"f08177fb-b34e-5589-a96c-46066ef57131","slug":"p-cresol","display_name":"Para-cresol / p-cresol","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"49aebce5-2fe5-5d4d-a43f-03c30ce8a1f4","stable_key":"63ce713e-6aea-59f6-9896-ca30e010b2ce:l-tyrosine-microbial-cresol-event","event_type":"observed_relationship","label":"The same precursor can feed a microbial competition mechanism.","description":"C. difficile fermented tyrosine to p-cresol; 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species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-tyrosine","display_name":"L-Tyrosine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"The same precursor can feed a microbial competition mechanism.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Para-cresol production by Clostridium difficile affects microbial diversity and membrane integrity of Gram-negative bacteria. · 2018 · https://pubmed.ncbi.nlm.nih.gov/30208103/ · DOI 10.1371/journal.ppat.1007191","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"2f5afb5f-71bb-540b-97d4-dec1d61381b9","evidence_kind":"source_excerpt","locator":"Lines 348-354","start_line":348,"end_line":354,"excerpt":"## l-tyrosine-microbial-cresol\nThe same precursor can feed a microbial competition mechanism.\nC. difficile fermented tyrosine to p-cresol; a p-cresol-deficient mutant had altered competitive fitness in co-culture and a mouse relapse model.\nModel: C. difficile parent/mutant strains, bacterial co-cultures and mouse infection model.\nLimitations: This does not quantify effects of a tyrosine supplement on human infection.\nEvidence access: Primary abstract\nPara-cresol production by Clostridium difficile affects microbial diversity and membrane integrity of Gram-negative bacteria. · 2018 · https://pubmed.ncbi.nlm.nih.gov/30208103/ · DOI 10.1371/journal.ppat.1007191","model_system":"C. difficile parent/mutant strains, bacterial co-cultures and mouse infection model.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"12917df2-c6e0-5b61-850f-dbff6d4b4d30","stable_key":"import-63ce713e-6aea-59f6-9896-ca30e010b2ce","title":"L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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