WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions.
Alishewanella is a genus of Gram-negative, facultative anaerobic bacteria within the class Gammaproteobacteria. Primarily known as environmental organisms, Alishewanella species have been identified in the microbiome of deep endometriosis — both in vaginal samples and w…
Ammonia is a nitrogen-containing product of microbial urease activity. When urease hydrolyzes urea, ammonia and bicarbonate are produced; in the microbial systems covered by WikiBiome, those products can provide nitrogen and raise local pH maier 2019 nickel microbial pa…
Antimicrobial metals are metal ions and metal-based materials that kill or inhibit microorganisms. Copper, silver, zinc, and gallium are the principal agents, each exploiting different aspects of microbial metal biology. What makes this field particularly relevant to Wi…
The ability of microorganisms to survive and replicate in the presence of antimicrobial agents — antibiotics, antifungals, antivirals, antiparasitic drugs — at concentrations that would normally inhibit or kill them. Antimicrobial resistance (AMR) is designated by the W…
Arsenic is a metalloid and potent carcinogen (IARC Group 1) that ranks among the most widespread environmental toxicants affecting human health. An estimated 225 million people worldwide are chronically exposed through contaminated drinking water alone ghosh 2023 heavy …
Cadmium is a toxic non-essential heavy metal (IARC Group 1 carcinogen) with a biological half-life of 17--30 years in mammals, primarily accumulating in the renal cortex via proximal tubular reabsorption of the Cd-metallothionein complex rasin 2025 cadmium exposure heal…
Clostridioides difficile is the current NCBI name for NCBITaxon:1496 and the correct, medically recommended combination recorded by LPSN. Both records retain Clostridium difficile as a validly published homotypic synonym of the same organism rather than a separate speci…
The process by which selection pressure from one agent — typically a heavy metal — simultaneously selects for resistance to a structurally unrelated agent such as an antibiotic, because the resistance determinants are genetically linked on the same mobile genetic elemen…
The co-occurrence of multiple diseases in the same individual at rates exceeding chance. Comorbidity patterns are a central puzzle in medicine -- why do IBD patients develop CVD? Why does PCOS cluster with T2D? Why do neurodegenerative diseases associate with depression…
Competitive exclusion is the ecological principle that two species competing for the same limiting resource cannot coexist indefinitely — one will outcompete the other. In the gut microbiome, competitive exclusion is the primary mechanism by which commensal bacteria pre…
Cross-feeding (syntrophy) is the metabolic cooperation in which one organism's waste product becomes another's substrate. It is the cooperative counterpart to competitive exclusion — rather than competing for the same resource, organisms partition metabolic labor into s…
A synthesis of how dietary heavy metal exposure varies across the human lifespan, highlighting that the same metals present different risks at different developmental stages due to changing absorption rates, detoxification capacity, dietary patterns, and organ vulnerabi…
Dysmenorrhea -- painful menstruation -- is the most common gynecological complaint, affecting 50-90% of reproductive-age women. It is classified as primary (no identifiable pelvic pathology) or secondary (caused by conditions such as endometriosis, adenomyosis, or fibro…
Membrane-spanning protein complexes that actively export substrates from the bacterial cell, using energy from ATP hydrolysis or the proton motive force. In the context of metal-microbiome biology, efflux pumps serve a dual role that has profound clinical consequences: …
A genus of Gram-positive bacteria (primarily E. faecalis and E. faecium) that exemplifies the metal-antibiotic resistance co-selection crisis. Enterococci carry diverse metal tolerance genes for mercury, arsenic, copper, and cadmium on the same mobile genetic elements a…
Epigenetic modifications — heritable changes in gene expression without altering the DNA sequence — are a primary mechanism through which both heavy metals and the gut microbiome influence disease across the lifespan. The three major epigenetic mechanisms (DNA methylati…
Epigenetics is the study of heritable changes in gene expression that occur without alterations to the DNA sequence itself. These changes -- primarily DNA methylation, histone modifications, and non-coding RNA regulation -- represent a molecular memory system that can b…
Erectile dysfunction (ED) affects 30-50% of men aged 40-70 Feldman et al. 1994, with prevalence increasing with age. Conventionally understood as a vascular and/or neurogenic disorder, ED is now recognized as a condition with a significant gut microbiome component -- th…
The primary intracellular iron storage protein, capable of sequestering up to 4,500 iron atoms in a single molecule as a mineralized ferric oxyhydroxide core. Ferritin is one of the most elegant solutions evolution has produced for the iron paradox: iron is essential fo…
The fifth most common cancer worldwide and third leading cause of cancer death, with over 1 million new cases annually. Gastric cancer stands unique in this wiki as the disease where a single microorganism -- helicobacter pylori -- provides the dominant causal pathway, …
Alphabetical definitions of specialist terms used throughout this wiki. Where a full concept page exists, the term links to it. --- AhR (aryl hydrocarbon receptor) -- A ligand-activated transcription factor that senses microbial metabolites (especially indoles from tryp…
The gut-penis axis is an emerging concept describing the systemic pathway by which gut microbiome dysbiosis impairs erectile function through endothelial nitric oxide (NO) suppression and chronic inflammation. Though less established than the gut-brain or gut-heart axes…
Heavy metals is a widely used but chemically imprecise umbrella term for elements discussed because of their density, persistence, environmental occurrence, or toxicity. One common convention uses density above 5 g/cm3, but density alone does not determine biological ha…
Horizontal gene transfer (HGT) is the movement of genetic material between organisms outside of parent-to-offspring inheritance. In the gut microbiome, HGT -- primarily mediated by mobile genetic elements (MGEs) including plasmids, transposons, integrons, and integrativ…
Hyperaccumulator plants are species that concentrate heavy metals in their tissues at 10–100× the levels found in non-accumulating species growing in the same soil. Over 700 plant species are known hyperaccumulators — primarily for nickel (~530 species), but also zinc, …
An umbrella term for chronic relapsing-remitting inflammatory conditions of the gastrointestinal tract, principally crohns disease (CD; transmural, any GI segment) and ulcerative colitis (UC; mucosal, colon only). Approximately 6 million patients worldwide. IBD represen…
Lachnospira eligens (Holdeman and Moore 1974) García-López et al. 2020 is the selected current name for NCBITaxon:39485. NCBI Taxonomy lists Eubacterium eligens as its basionym, and LPSN treats the two combinations as homotypic synonyms based on the same type strain, AT…
Mendelian randomization (MR) is a statistical method that uses genetic variants as instrumental variables to infer causal relationships between an exposure (e.g., gut microbiome composition) and an outcome (e.g., disease). Because genetic variants are randomly allocated…
Metabolomics is the comprehensive measurement of small-molecule metabolites (<1,500 Da) in a biological sample -- the functional readout of what the genome, transcriptome, and microbiome are actually doing. While genomics tells you what organisms are present and metagen…
Metal resistance genes encode proteins that allow bacteria to survive toxic metal concentrations through efflux pumps, enzymatic detoxification, or sequestration mechanisms. These genes are frequently carried on mobile genetic elements (plasmids, transposons, integrativ…
A metal ion that activates estrogen receptors and mimics the biological effects of estradiol. Metalloestrogens represent a distinct class of endocrine-disrupting compounds where the active agent is an inorganic metal rather than an organic xenoestrogen like BPA or phtha…
Methylation is the addition of a methyl group (-CH₃) to DNA, histones, proteins, or small molecules. DNA methylation (at CpG sites) is the primary epigenetic mechanism silencing gene expression, and it requires the methyl donor S-adenosylmethionine (SAMe), which depends…
This knowledge-base record is being expanded from WikiBiome’s evidence graph.
Nakaseomyces glabratus is the current name for NCBITaxon:5478. Takashima and Sugita established the current combination in 2022 as MycoBank MB 843854; Candida glabrata is a homotypic synonym and former combination, while Cryptococcus glabratus H.W. Anderson 1917 is the …
Necrotizing enterocolitis (NEC) is the most common and lethal gastrointestinal emergency in premature infants, affecting 5-12% of very low birth weight neonates (<1500 g) with mortality rates of 20-30%. Characterized by intestinal inflammation, necrosis, and perforation…
NiFe-hydrogenase (also called [Ni-Fe] hydrogenase or nickel-iron hydrogenase) is a class of enzymes that catalyze reversible hydrogen (H₂) oxidation. The active site contains both nickel (Ni) and iron (Fe) metal atoms arranged in a sophisticated bimetallic cluster. The …
Pancreatic cancer is the fifth leading cause of cancer death in Western nations, with rising incidence globally. Pancreatic ductal adenocarcinoma (PDAC) accounts for over 90% of cases. Five-year survival remains approximately 12%, owing to late-stage diagnosis, aggressi…
Peptidoglycan (murein) is the polymer of N-acetylglucosamine and N-acetylmuramic acid cross-linked by short peptides that forms the bacterial cell wall. It is a major pathogen-associated molecular pattern (PAMP) recognized by host TLR2 (intact peptidoglycan), NOD1 (meso…
A genus of Gram-positive, obligate anaerobic cocci within the Firmicutes phylum that exemplifies dual-nature microbiology — containing both keystone beneficial species and disease-associated pathobionts within the same genus. The genus spans multiple former taxonomic gr…
Shotgun metagenomics is a sequencing approach that fragments and sequences all DNA in a sample -- bacterial, archaeal, fungal, viral, and host -- without prior amplification of a specific gene target. Unlike 16S rRNA amplicon sequencing, which identifies "who is there" …
Lei et al. (2018) demonstrated that hydrogen sulfide promotes endometrial stromal cell proliferation via NF-kB activation. CBS and CSE (H2S-producing enzymes) are overexpressed in ectopic endometrium. NF-kB is also activated by nickel exposure in allergic contact mucosi…
Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that form the front line of the innate immune system. They detect conserved molecular patterns from microbes -- pathogen-associated molecular patterns (PAMPs) -- and damage-associated molecu…
Uremic toxins are metabolic waste products that accumulate in the blood when kidney function declines. A striking proportion of the most clinically significant uremic toxins are produced not by human metabolism but by the gut microbiome -- making the gut-kidney axis a c…
Zinc is the most widely utilized transition metal cofactor in biology. Approximately 9-10% of the eukaryotic proteome and 5-6% of the bacterial proteome consists of zinc-binding proteins capdevila 2024 bacterial metallostasis sensing trafficking. An estimated one-third …