All articles A–Z
519,064 articles
Spheroplast
Spheroplasts: bacteria or yeast that have partially lost their cell wall and become round; wall-less Gram-negative forms retaining an outer membrane, used in patch clamp, imaging, transformation, and DNA delivery.
Spherulite
A spherulite is a spherically symmetric aggregate of fibrillar crystals that grow radially from a common nucleation center, formed when polymers and minerals crystallize from viscous melts at large undercooling.
Sphettos
Sphettos (Σφηττός, Sphettus), an inland Athenian deme of tribe Akamantis near modern Koropi in the Mesogaia; one of Theseus's twelve townships, with a theatre of Dionysos and the honorand Kallias of SEG 28.60.
Sphex pensylvanicus
Sphex pensylvanicus, the great black wasp or katydid hunter, is a 22–28 mm solitary digger wasp of North America (except the northwest) that nests in soft soil and provisions brood cells with 2–6 paralyzed katydids per cell.
Sphincter
A sphincter is a ring-shaped muscle that relaxes or tightens to open and close passages in the body, controlling the flow of food, urine, and stool.
Sphincterotomy
Sphincterotomy is an endoscopic procedure that cuts the biliary sphincter with high-frequency current, usually during ERCP, most often to treat gallstones lodged in the common bile duct.
Sphinganine
Sphinganine, also called dihydrosphingosine, is a saturated 18-carbon amino alcohol that is the first long-chain base made in de novo sphingolipid biosynthesis; its ratio to sphingosine is a biomarker of fumonisin mycotoxin exposure.
Sphingidae
Sphingidae, known as hawkmoths or sphinx moths, is a family of about 1,450 moth species found on every continent except Antarctica, whose hornworm caterpillars include major crop pests.
Sphingolipid
Sphingolipids: membrane and signaling lipids built on a sphingoid base backbone such as sphingosine, named by Thudichum in 1884. Key metabolites include ceramide and sphingosine-1-phosphate; dysregulation links to cardiovascular, metabolic, and neurodegenerative disease.
Sphingolipid metabolism
Sphingolipid metabolism is the biochemical network that makes, converts, and breaks down sphingolipids, with ceramide as its central hub and roles in apoptosis and disease.
Sphingomonas
Sphingomonas (Yabuuchi et al. 1990), type species S. paucimobilis: Gram-negative, aerobic rods with glycosphingolipids instead of LPS; biodegrade PAHs and dioxins, produce gellan sphingans, promote plant growth, and occasionally cause nosocomial infections.
Sphingomyelin
Sphingomyelin (ceramide-1-phosphocholine, SM) is a sphingolipid phospholipid with a phosphocholine head group, abundant in the outer plasma-membrane leaflet, lipid rafts, and lipoproteins; its metabolism via sphingomyelinases and synthases links it to Niemann-Pick disease and atherosclerosis.
Sphingomyelin phosphodiesterase
Sphingomyelin phosphodiesterase (EC 3.1.4.12), also called acid or neutral sphingomyelinase, hydrolyzes sphingomyelin to ceramide and phosphocholine; SMPD1 deficiency causes Niemann-Pick disease types A/B.
Sphingomyelinase C/phospholipase C
Sphingomyelinase C/phospholipase C (InterPro IPR017766) is a DNase I-fold enzyme family; bacterial SMase C (EC 3.1.4.12) cleaves sphingomyelin to ceramide and phosphorylcholine and acts as a secreted virulence factor.
Sphingomyelinase D
Sphingomyelinase D (SMase D) is a phospholipase D enzyme that acts as the principal tissue-destroying toxin in brown recluse spider venom, causing dermonecrosis and intravascular hemolysis.
Sphingosine
Sphingosine is an 18-carbon amino alcohol, named after the Sphinx in 1884, that serves as the backbone of sphingolipids and acts as a broad-spectrum antimicrobial on epithelial surfaces.
Sphingosine 1-phosphate receptor
Sphingosine 1-phosphate receptors (S1PR1-5, formerly EDG receptors) are lipid G protein-coupled receptors for sphingosine 1-phosphate, regulating vascular tone, cardiac rhythm, and lymphocyte trafficking, and targeted by fingolimod and other multiple sclerosis drugs.
Sphingosine 1-phosphate receptor 1
S1PR1 (EDG-1, CD363) is a 382-amino-acid human Gi-coupled GPCR for sphingosine 1-phosphate that controls lymphocyte egress, angiogenesis, and endothelial barrier function, and is the target of MS drugs fingolimod, siponimod, ozanimod, and ponesimod.
Sphingosine-1-phosphate
Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid made by sphingosine kinases SPHK1/SPHK2, signals through five GPCRs (S1PR1-5) controlling lymphocyte trafficking and vascular integrity; receptor modulators fingolimod, siponimod, ozanimod, and ponesimod treat multiple sclerosis.
Sphinx
Sphinx: hybrid creature with a lion's body and human head, known in Egypt and Mesopotamia from the mid-3rd millennium BCE. Egyptian male royal guardian (Great Sphinx of Giza); Greek winged female monster of Thebes defeated by Oedipus's riddle answer, Man.
Sphinx of Memphis
The Sphinx of Memphis, also called the Alabaster Sphinx, is a colossal calcite statue uncovered at Mit Rahina in 1912, the largest sphinx after the Great Sphinx of Giza.
Sphinx of Taharqo
The Sphinx of Taharqo, also known as the Sphinx of Taharqa, is a granite sphinx of the Kushite pharaoh Taharqo, found at Kawa in Sudan and now in the British Museum.
Sphinx of Tanis
The Sphinx of Tanis, also known as the Great Sphinx of Tanis, is a monumental rose granite sphinx found at Tanis in the Nile Delta and displayed in the Louvre since 1826.
Sphinx Systems
Sphinx Systems, also known as Sphinx Systems Limited, was a Swiss manufacturer of hand-fitted semi-automatic pistols such as the Sphinx 3000, founded in 1876 and bankrupt by 2015.
Sphinx water erosion hypothesis
Sphinx water erosion hypothesis: Robert Schoch and John Anthony West's claim that rainfall runoff, not wind, weathered the Giza Sphinx enclosure, implying a date far older than the conventional Khafre attribution around 2500 BCE.
SPHK1
SPHK1 (sphingosine kinase 1, SphK1, SK1) is a human lipid kinase, EC 2.7.1.91, on chromosome 17q25.1, that phosphorylates sphingosine to sphingosine-1-phosphate, promoting cell growth, survival, and inflammatory signaling, distinct from the pro-apoptotic SphK2 isoform.
SPHL
SPHL (Southern Professional Hockey League), founded 2004, independent class-A minor hockey league in the U.S. Southeast and Midwest; President's Cup champion, ECHL feeder, 13 teams by 2026-27.
Sphoṭa (स्फोट)
Sphoṭa (स्फोट), "burst," is the Sanskrit grammarians' indivisible meaning-bearing linguistic entity, manifested by but distinct from speech sounds; developed by Bhartṛhari in the Vākyapadīya, opposed by Kumārila, Jayanta, and Śaṅkara.
Sphoungaras
Sphoungaras is a Minoan cemetery on a hill about 300 meters north of the Bronze Age town of Gournia in eastern Crete, known for pithos burials in large clay storage jars.
Sphujidhvaja
Sphujidhvaja (स्फुजिध्वज) was the author, or named transmitter, of the Yavanajataka, a Sanskrit verse work on Greek-style horoscopic astrology, traditionally composed in 269/270 CE in the realm of the Western Kshatrapas.