Component

Para-cresol / p-cresol

Context-specific entity; species, compartment and exposure are stated on each claim.

4 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Exogenous p-cresol impaired susceptible Gram-negative bacterial membrane integrity; Gram-positive organisms were generally more tolerant.

    Para-cresol / p-cresol → Gram-negative bacterial membrane integrity under p-cresol exposure source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Defined bacterial exposure and membrane-integrity assays.
    limitations
    Susceptibility varies among organisms; no human systemic toxicity threshold is inferred.
    nutrient_topic
    L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Tyrosine
    plain_language
    A microbial breakdown product affects other community members.
    primary_references
    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

    L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 356–362

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Defined bacterial exposure and membrane-integrity assays. · source_derived_draft · unverified_draft

    ## l-tyrosine-cresol-membranes A microbial breakdown product affects other community members. Exogenous p-cresol impaired susceptible Gram-negative bacterial membrane integrity; Gram-positive organisms were generally more tolerant. Model: Defined bacterial exposure and membrane-integrity assays. Limitations: Susceptibility varies among organisms; no human systemic toxicity threshold is inferred. Evidence access: Primary abstract 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
    Complete structured claim and evidence

What acts on it

  1. C. difficile fermented tyrosine to p-cresol; a p-cresol-deficient mutant had altered competitive fitness in co-culture and a mouse relapse model.

    Clostridioides difficile tyrosine fermentation → Para-cresol / p-cresol source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    C. difficile parent/mutant strains, bacterial co-cultures and mouse infection model.
    limitations
    This does not quantify effects of a tyrosine supplement on human infection.
    nutrient_topic
    L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Tyrosine
    plain_language
    The same precursor can feed a microbial competition mechanism.
    primary_references
    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

    L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 348–354

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · C. difficile parent/mutant strains, bacterial co-cultures and mouse infection model. · source_derived_draft · unverified_draft

    ## l-tyrosine-microbial-cresol The same precursor can feed a microbial competition mechanism. C. difficile fermented tyrosine to p-cresol; a p-cresol-deficient mutant had altered competitive fitness in co-culture and a mouse relapse model. Model: C. difficile parent/mutant strains, bacterial co-cultures and mouse infection model. Limitations: This does not quantify effects of a tyrosine supplement on human infection. Evidence access: Primary abstract 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
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Loss of two C. difficile ABC-transporter genes was associated with lower tyrosine/phenylalanine uptake and p-cresol production, without a measurable growth or enterotoxin effect.

    Clostridioides difficile aromatic amino-acid ABC transport system → Clostridioides difficile tyrosine fermentation source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary abstract
    experimental_model
    Genomic and phenotypic strain comparisons; convergent loss and laboratory emergence.
    limitations
    Association is retained as such; this is not direct human host transporter evidence.
    nutrient_topic
    L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Tyrosine
    plain_language
    Microbial access to a nutrient can change its products without stopping growth.
    primary_references
    Convergent Loss of ABC Transporter Genes From Clostridioides difficile Genomes Is Associated With Impaired Tyrosine Uptake and p-Cresol Production. · 2018 · https://pubmed.ncbi.nlm.nih.gov/29867812/ · DOI 10.3389/fmicb.2018.00901
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 364–370

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Genomic and phenotypic strain comparisons; convergent loss and laboratory emergence. · source_derived_draft · unverified_draft

    ## l-tyrosine-bacterial-import Microbial access to a nutrient can change its products without stopping growth. Loss of two C. difficile ABC-transporter genes was associated with lower tyrosine/phenylalanine uptake and p-cresol production, without a measurable growth or enterotoxin effect. Model: Genomic and phenotypic strain comparisons; convergent loss and laboratory emergence. Limitations: Association is retained as such; this is not direct human host transporter evidence. Evidence access: Primary abstract Convergent Loss of ABC Transporter Genes From Clostridioides difficile Genomes Is Associated With Impaired Tyrosine Uptake and p-Cresol Production. · 2018 · https://pubmed.ncbi.nlm.nih.gov/29867812/ · DOI 10.3389/fmicb.2018.00901
    Complete structured claim and evidence

  2. Higher predose urinary p-cresol sulfate was associated with a lower postdose acetaminophen sulfate-to-glucuronide ratio.

    p-Cresol sulfate → Human urinary acetaminophen sulfate-to-glucuronide ratio source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_access
    Primary abstract
    experimental_model
    Human predose/postdose urine NMR after a standard acetaminophen dose.
    limitations
    The authors proposed competition for O-sulfonation; the association does not prove tyrosine intake depletes sulfate or increases drug toxicity.
    nutrient_topic
    L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Tyrosine
    plain_language
    Microbial metabolism can correlate with how a drug is processed.
    primary_references
    Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19667173/ · DOI 10.1073/pnas.0904489106
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 372–378

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human predose/postdose urine NMR after a standard acetaminophen dose. · source_derived_draft · unverified_draft

    ## l-tyrosine-cresol-drug-sulfation Microbial metabolism can correlate with how a drug is processed. Higher predose urinary p-cresol sulfate was associated with a lower postdose acetaminophen sulfate-to-glucuronide ratio. Model: Human predose/postdose urine NMR after a standard acetaminophen dose. Limitations: The authors proposed competition for O-sulfonation; the association does not prove tyrosine intake depletes sulfate or increases drug toxicity. Evidence access: Primary abstract Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19667173/ · DOI 10.1073/pnas.0904489106
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

    Evidence, AI assistance and curation standards