WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions.
The intestinal epithelium is a single-cell-thick barrier separating the lumen -- home to trillions of microbes and ingested metals -- from the systemic circulation. When this barrier fails, the consequences cascade: microbial products translocate, metals gain unrestrict…
Roseburia intestinalis is a Gram-positive, obligate anaerobic member of the Lachnospiraceae family (Firmicutes). It is one of the most important butyrate producers in the human colon, converting dietary fiber into butyrate — the primary energy source for colonocytes and…
An acidic microenvironment is a local drop in pH — typically into the 4.5–6.5 range — inside a tissue, organ, or ecological niche. Acidification arises from three recurring sources: bacterial fermentative metabolism that releases short-chain fatty acids and lactate (lou…
A pathotype of escherichia coli that adheres to and invades intestinal epithelial cells, survives and replicates within macrophages, and is strongly associated with ileal Crohn's disease. Unlike classical diarrheagenic E. coli pathotypes (EPEC, ETEC, EHEC), AIEC does no…
Aeromonas is a genus of Gram-negative, facultatively anaerobic bacteria found in aquatic environments and, increasingly recognized as an opportunistic gut pathogen. Several species — particularly Aeromonas hydrophila, A. veronii, and A. caviae — are associated with gast…
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that functions as a master sensor at the intersection of gut microbial metabolism, environmental chemical exposure, and immune regulation. It is expressed broadly across immune cells, intesti…
A Gram-negative, obligate anaerobic, mucin-degrading bacterium that colonizes the intestinal mucus layer and has emerged as one of the most important next-generation probiotics. A. muciniphila is consistently depleted in disease states associated with metal dyshomeostas…
Anaerococcus is a genus of Gram-positive, obligate anaerobic cocci within the phylum Firmicutes. It is a normal inhabitant of the human vaginal, skin, and gastrointestinal microbiota, but is recognized as an opportunistic pathogen in dysbiotic states, particularly when …
Anxiety disorders are the most prevalent mental health conditions globally, affecting ~280 million people (~4.8% of the world population). They encompass generalized anxiety disorder (GAD), social anxiety, panic disorder, and phobias. In the WikiBiome context, anxiety f…
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 …
Aspirin (acetylsalicylic acid) is a non-steroidal anti-inflammatory drug (NSAID) that irreversibly inhibits cyclooxygenase (COX) enzymes, suppressing prostaglandin synthesis. While widely used as an antiplatelet and anti-inflammatory agent, aspirin carries significant i…
The Autoimmune Protocol (AIP) diet is an elimination diet that removes foods associated with increased intestinal permeability and autoimmune activation. In Hashimoto's thyroiditis, it targets the gut-thyroid connection by reducing antigenic triggers that drive molecula…
Bacteroides is the most abundant genus in the Western adult gut and a cornerstone of intestinal polysaccharide metabolism. As members of the bacteroidetes phylum, Bacteroides species encode enormous repertoires of carbohydrate-active enzymes (CAZymes) organized into pol…
Bacteroidetes (recently reclassified as Bacteroidota) is one of the two dominant bacterial phyla in the human gut, together with firmicutes typically comprising 90% of the intestinal microbiota. Bacteroidetes are Gram-negative, obligately anaerobic, non-spore-forming ro…
Barrett's esophagus (BE) is a premalignant condition in which the normal squamous epithelium of the distal esophagus is replaced by intestinal-type columnar epithelium (intestinal metaplasia). It is the primary risk factor for esophageal adenocarcinoma (EAC), a cancer w…
A heavy metal traditionally considered safe enough for over-the-counter gastrointestinal remedies (Pepto-Bismol, De-Nol), bismuth is re-emerging as a potent antimicrobial synergist. Its key property: Bi3+ competes with Fe3+ for binding sites on siderophores and bacteria…
A genus of Gram-negative intracellular pathogens causing brucellosis, the most common bacterial zoonosis worldwide. Brucella species depend on nickel-activated urease for gastrointestinal survival during the initial phase of infection, and urease immunization has been s…
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…
Cardiovascular disease (CVD) -- encompassing atherosclerosis, coronary artery disease, hypertension, myocardial infarction, heart failure, and stroke -- is the leading cause of death globally. The gut-heart axis has emerged as a central paradigm linking microbial metabo…
Celiac disease is a chronic autoimmune condition triggered by dietary gluten (gliadin proteins from wheat, barley, and rye) in genetically susceptible individuals (HLA-DQ2/DQ8, carried by ~30-40% of Europeans but penetrant in only ~1% of carriers). Gluten exposure cause…
Cerebral palsy (CP) is the most common motor disability in childhood, affecting 2-3 per 1,000 live births allen 2021 multi organ dysfunction cerebral palsy. Characterized by non-progressive disturbances in movement and posture arising from injury to the developing brain…
Cholestasis is the impairment or cessation of bile flow from the liver to the duodenum. It can be intrahepatic (hepatocyte or bile ductule dysfunction) or extrahepatic (mechanical obstruction). Beyond its direct hepatic consequences, cholestasis profoundly disrupts the …
Chromium is a transition metal (atomic number 24) whose toxicology is defined by a stark oxidation-state divide. Hexavalent chromium, Cr(VI), is an IARC Group 1 human carcinogen that causes DNA damage through a unique mechanism of intracellular reduction and ternary add…
Clostridium perfringens is a Gram-positive, strictly anaerobic, spore-forming bacterium infamous for causing gas gangrene, food poisoning, and necrotizing enterocolitis (NEC) in premature infants. It is one of the most widely distributed pathogenic bacteria in nature, f…
Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer death. Over 90% of cases are sporadic, driven by a complex interplay between genetic predisposition, dietary habits, gut microbiome composition, and environmental ex…
A chronic, relapsing-remitting inflammatory bowel disease (IBD) characterized by transmural inflammation of the gastrointestinal tract, most commonly affecting the terminal ileum and colon but capable of involving any segment from mouth to anus zhang 2017 intestinal mic…
Defensins are small (29–45 amino acid) cationic antimicrobial peptides that form the first line of chemical defense at mucosal surfaces. Alpha-defensins (HD5, HD6) are produced by Paneth cells in the small intestinal crypts; beta-defensins (hBD1-4) are produced by epith…
Depression is the most prevalent mental health disorder globally, affecting over 280 million people zhu 2025 microbiota gut brain axis depression review, and one of the most metal-sensitive conditions in this wiki. It sits at the convergence of nearly every pathway cata…
Dermatitis herpetiformis (DH) is the cutaneous manifestation of celiac disease, presenting as intensely pruritic, grouped vesicles on the elbows, knees, buttocks, and scalp. It is driven by IgA antibodies against epidermal transglutaminase (eTG), the skin homolog of tis…
A Gram-positive obligate anaerobe and key estrobolome member that links metabolic dysbiosis to hormone-driven diseases, particularly endometriosis. E. lenta is remarkable for its ability to inactivate cardiac glycosides (like digoxin) and to produce beta-glucuronidase, …
Enterococcus faecalis is a Gram-positive, facultatively anaerobic coccus that inhabits the gastrointestinal tract, oral cavity, and genitourinary tract of humans. It is a commensal in the healthy gut at low abundance but is one of the most clinically significant opportu…
Enterohepatic circulation (EHC) is the recycling loop by which compounds—primarily bile acids, conjugated estrogens, conjugated glucuronides, and metabolites of drugs and xenobiotics—are excreted in bile, reach the intestine, undergo deconjugation or dehydroxylation by …
Epilepsy is a chronic neurological disorder characterized by recurrent unprovoked seizures, affecting ~50 million people worldwide. Approximately 30% of patients have drug-resistant epilepsy -- a population where microbiome-targeted interventions (particularly the ketog…
Epithelial-mesenchymal transition (EMT) is a cellular program in which polarized epithelial cells lose their cell-cell adhesion and acquire migratory, mesenchymal properties. While essential during embryonic development and wound healing, aberrant EMT activation drives …
Erysipelotrichaceae is a family within the phylum Firmicutes that has drawn increasing attention for its consistent enrichment in metabolic disorders. Members of this family are Gram-positive, obligate anaerobes found throughout the mammalian gastrointestinal tract, whe…
Estrogen recirculation is the recycling loop by which conjugated estrogens excreted in bile are deconjugated by gut bacterial beta glucuronidase, reabsorbed across the intestinal epithelium, and returned to systemic circulation uzuner 2023 bidirectional relationship end…
The most abundant bacterium in the healthy human colon (5-15% of total fecal microbiota), F. prausnitzii is the premier butyrate producer in the gut and a cornerstone of anti-inflammatory intestinal homeostasis. Its depletion is one of the most consistent microbiome sig…
The farnesoid X receptor (FXR), also known as NR1H4, is a nuclear receptor that functions as the primary bile acid sensor in the body. Activated by bile acids — especially chenodeoxycholic acid (CDCA) — FXR regulates bile acid synthesis, cholesterol metabolism, glucose …
The transfer of processed stool from a healthy donor into a recipient's gastrointestinal tract to restore a disrupted microbial community. FMT is the most direct form of microbiome intervention -- replacing the entire community rather than supplementing individual strai…
Finegoldia is a genus of Gram-positive, strictly anaerobic cocci, with Finegoldia magna as the primary species of clinical relevance. Formerly classified within Peptostreptococcus, this organism inhabits mucosal surfaces including the vaginal, skin, and gastrointestinal…
Firmicutes (recently reclassified as Bacillota) is the dominant bacterial phylum in the Western adult gut, comprising the core community of short-chain fatty acid (SCFA) producers that maintain intestinal barrier integrity, regulate immune function, and influence system…
Fusicatenibacter is a Gram-positive obligate anaerobic genus within the Lachnospiraceae (Firmicutes). The primary species, F. saccharivorans, was isolated from human feces and is recognized as a beneficial commensal that produces butyrate and modulates intestinal immune…
A Gram-negative obligate anaerobe that has emerged as a major pathogen in colorectal cancer (CRC) and inflammatory bowel disease. F. nucleatum is significantly enriched in CRC tissue and tumors compared to healthy mucosa, making it one of the strongest microbe-cancer as…
A Gram-negative obligate anaerobe that occupies a paradoxical niche in the gut microbiota: as a weak butyrate producer (short-chain fatty acid), it has anti-inflammatory potential; as a virulent invasive pathobiont in inflammatory bowel disease (particularly ulcerative …
Gastroesophageal reflux disease (GERD) is a chronic condition in which stomach acid or bile flows back into the esophagus, causing mucosal damage and symptoms such as heartburn and regurgitation. Affecting approximately 20% of Western populations, GERD is conventionally…
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…
Graves' disease (GD) is an autoimmune thyroid disorder characterized by TSH receptor antibodies (TRAb) that stimulate the thyroid gland, causing hyperthyroidism kahaly 2022 graves disease targeted therapy review. It is the most common cause of hyperthyroidism, with conc…
Gut barrier dysfunction -- colloquially "leaky gut" -- is the pathological increase in intestinal permeability that permits translocation of bacteria, bacterial products (LPS, peptidoglycan), metals, and dietary antigens from the gut lumen into the systemic circulation.…
The community of trillions of microorganisms — bacteria, archaea, fungi (mycobiome), viruses, and bacteriophages — inhabiting the human gastrointestinal tract, with the highest density in the colon (~10¹¹ cells/g). The gut microbiome encodes 100–150 times more genes tha…
The gut-gonadal axis describes the bidirectional communication between the intestinal microbiome and the reproductive endocrine system. Gut bacteria modulate sex hormone levels through enzymatic activity (particularly beta glucuronidase-mediated estrogen deconjugation),…
The gut-kidney axis describes the bidirectional relationship between the gut microbiome and kidney function. As kidney disease progresses, the resulting biochemical changes (uremia, altered pH, fluid shifts) reshape the gut microbiome. The dysbiotic microbiome, in turn,…
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…
The gut-vagina axis describes the bidirectional relationship between the intestinal and vaginal microbiomes. Emerging evidence shows that gut microbial composition influences vaginal colonization patterns through immune modulation, metabolite exchange, and direct microb…
Haemophilus is a genus of small, Gram-negative, facultatively anaerobic coccobacilli that inhabit the upper respiratory tract, oral cavity, and gastrointestinal tract. The genus name literally means "blood-loving" -- a direct reference to its absolute requirement for he…
A Gram-negative, microaerophilic bacterium within the Epsilonproteobacteria (family Helicobacteraceae) that is the primary murine model of hepatobiliary and intestinal disease. Unlike its more famous relative helicobacter pylori, which colonizes the stomach, H. hepaticu…
Hypoxia refers to a state of low oxygen tension (partial pressure of O₂ < 5% in tissue, vs. ~21% in air). In the context of microbiome metallomics, hypoxia is a critical ecological determinant that reshapes bacterial community structure by favoring obligate and facultat…
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…
A functional gastrointestinal disorder affecting 10-15% of the global population, characterized by chronic abdominal pain, bloating, and altered bowel habits (diarrhea-predominant, constipation-predominant, or mixed) without identifiable structural pathology. From a met…
Lactobacillus rhamnosus is a Gram-positive, facultatively anaerobic lactic acid bacterium and one of the most extensively studied probiotic species. The GG strain (ATCC 53103), isolated from a healthy human intestinal tract by Gorbach and Goldin in 1983, is the single m…
Lead is a purely toxic heavy metal with no known biological function. It is the most extensively studied metal in relation to neurodevelopmental harm and is increasingly recognized as a contributor to chronic disease across virtually every organ system, even at levels o…
A Gram-negative obligate anaerobe traditionally considered an oral commensal, but increasingly recognized as an opportunistic pathobiont with the ability to translocate from oral biofilms to the gastrointestinal tract and bloodstream. Leptotrichia species are prominentl…
Maternal immune activation (MIA) describes the phenomenon in which infection or inflammatory stimulation during pregnancy produces persistent neurological and microbiome alterations in offspring, increasing risk for autism spectrum disorder, schizophrenia, and other neu…
Mercury is the most toxic heavy metal with no known biological function. Its organic form -- methylmercury (MeHg) -- is the primary concern for dietary exposure via fish consumption. Mercury's toxicity centers on thiol group binding, glutathione depletion, and blood-bra…
Morganella morganii is a Gram-negative, facultatively anaerobic rod belonging to the family Morganellaceae (formerly classified within Enterobacteriaceae). It inhabits the human gastrointestinal tract as a low-abundance commensal but becomes an opportunistic pathogen in…
Mortierella is a genus of soil-dwelling fungi in the phylum Mortierellomycota (formerly placed in Zygomycota). While primarily known as environmental saprotrophs, Mortierella species have recently been identified as residents of the human gut mycobiome -- the fungal com…
Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system, with a global prevalence of approximately 2.8 million attfield 2022 immunology ms nature review. The conventional framing centers on genetic susceptibility (HLA-DRB115:0…
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…
Non-alcoholic fatty liver disease (NAFLD), recently reclassified as metabolic dysfunction-associated steatotic liver disease (MASLD), encompasses a spectrum from simple hepatic steatosis to metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH), fibrosis…
The oral microbiome is the second most complex microbial community in the human body after the gut, harboring ~700 species across distinct niches (tongue, buccal mucosa, gingival crevice, saliva, dental plaque). While traditionally studied in the context of dental disea…
A family of Gram-positive obligate anaerobes (formerly classified as the genus Oscillospira, now reclassified into Oscillibacter and related genera within Oscillospiraceae) that serve as keystone butyrate producers in the healthy human distal colonic microbiota (Konikof…
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…
Pancreatitis is inflammation of the pancreas, occurring in acute (AP) and chronic (CP) forms. Acute pancreatitis ranges from mild self-limiting disease to severe necrotizing pancreatitis with 20-30% mortality. Chronic pancreatitis is a risk factor for pancreatic cancer …
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, flagellated bacteria within the lachnospiraceae family that ranks among the most important butyrate producers in the human gut. Key species include R. intestinalis and R. hominis. Roseburia is consistently depleted across in…
A Gram-positive obligate anaerobe that has emerged as a pro-inflammatory pathobiont enriched across multiple disease states including crohns disease, depression, and multiple sclerosis. R. gnavus produces a species-specific inflammatory polysaccharide that activates int…
See also: saccharomyces (genus page) Saccharomyces boulardii is a non-pathogenic yeast strain used as a probiotic across a wide range of gastrointestinal and inflammatory conditions. Taxonomically a strain of S. cerevisiae, it is phenotypically distinct — optimally acti…
A genus of Gram-negative, crescent-shaped, strictly anaerobic bacteria found in both the oral cavity and the gastrointestinal tract. Selenomonas species are characterized by their distinctive morphology -- a curved rod with a tuft of flagella arising from the concave si…
Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter with a remarkable split life: ~90-95% of body serotonin is produced in the gut by enterochromaffin (EC) cells, not in the brain. This peripheral serotonin regulates intestinal motility, secretion, vis…
Streptococcus thermophilus is a Gram-positive, facultative anaerobic coccus that is the primary probiotic species used in commercial yogurt fermentation and thermophilic dairy fermentation worldwide. Distinct from pathogenic Streptococcus species, S. thermophilus produc…