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Speos Artemidos
Speos Artemidos, also called the Speos of Pakhet, is a rock-cut temple for the lioness goddess Pakhet near Beni Hasan, begun by Queen Hatshepsut around 1473 BC.
Spercheiai
Spercheiai (Σπέρχεια, also Sperchiae) was a Classical-Hellenistic fortified settlement of the Spercheios valley in ancient Thessaly, ravaged by the Aitolians in 198 BC per Livy, probably at Kastrorachi or Makrakomi in Phthiotis, Greece.
Spergula
Spergula (spurry) is a Caryophyllaceae genus of annual herbs, published by Linnaeus in 1753, native to temperate Eurasia and southern South America; S. arvensis, corn spurrey, is a cereal weed producing 5,000-10,000 seeds per plant.
Spergula arvensis
Spergula arvensis (corn spurrey, corn spurry, sandweed) is an annual Caryophyllaceae weed of sandy acid arable land, native from Europe to NW. India and tropical Africa, with tiny whorled linear leaves, white flowers, a persistent seed bank, and ALS-herbicide-resistant biotypes in Norway.
Spergularia
Spergularia, sand-spurreys or sea-spurreys, a conserved genus of about 60-67 herbs in Caryophyllaceae, type S. rubra, diverse in the Mediterranean and temperate South America, mostly in saline coastal habitats.
Sperm
Sperm (spermatozoon) is the male gamete: a small, motile haploid cell with head, midpiece, and flagellum, discovered in 1677, requiring capacitation before fertilization and shaped evolutionarily by sperm competition.
Sperm bank
Sperm bank (semen bank): facility freezing and storing human sperm in liquid nitrogen for donor insemination or fertility preservation. First frozen-sperm births 1953 by Bunge and Sherman in Iowa; first banks 1964; FDA screening and family limits govern donors.
Sperm banking
Sperm banking is a reproductive medicine service that collects, freezes, and stores sperm in liquid nitrogen, mainly to preserve fertility before cancer treatment and for donor conception.
Sperm competition
Sperm competition, also called post-copulatory sexual selection, is competition between sperm of different males to fertilize a female's eggs; founded by Geoff Parker's 1970 insect review, it drives larger testes, longer sperm, strategic ejaculation, and cryptic female choice.
Sperm Count
Sperm count, also called semen analysis, measures the number of sperm in an ejaculate; WHO 6th edition (2021) 5th centile is 16 million/ml concentration, 39 million total, not a fertile-infertile cutoff.
Sperm cryopreservation
Sperm cryopreservation is a reproductive medicine technique that freezes and stores sperm at −196 °C in liquid nitrogen for later insemination, IVF, or ICSI, preserving fertility before cancer treatment.
Sperm donation
Sperm donation, also called donor insemination via sperm banks, provides semen for women or couples needing third-party conception. Distinguished by FDA/ASRM screening, 6-month quarantine, family-size limits, and varying anonymity laws.
Sperm mitochondrial-associated cysteine-rich protein
SMCP (sperm mitochondrial-associated cysteine-rich protein, gene SMCP, UniProt P49901) is a cysteine- and proline-rich structural protein of the sperm mitochondrial capsule supporting sperm motility and zona pellucida penetration; not the selenoprotein once assumed.
Sperm Motility
Sperm motility, the movement characteristics of spermatozoa in fresh semen, is graded by WHO as progressive, non-progressive, or immotile, with a 30% progressive reference limit, measured manually or by CASA.
Sperm retrieval
Sperm retrieval, also called testicular sperm retrieval, is a group of surgical procedures collecting sperm from the epididymis or testis for ICSI in azoospermia, used routinely since 1992.
Sperm whale
The sperm whale (Physeter macrocephalus) is the largest toothed whale, a deep-diving oceanic predator named for the spermaceti oil in its oversized head, diving about 800 meters to hunt giant squid.
Sperm-associated antigen 5
Sperm-associated antigen 5 (SPAG5), also called astrin or MAP126, is a human 17q11.2 mitotic spindle protein regulating sister chromatid separation, kinetochore attachments, and an overexpressed oncogenic prognostic biomarker in many cancers.
Spermaceti
Spermaceti (cetaceum, spermaceti wax, CAS 8002-23-1) is the cetyl palmitate-rich wax from the sperm whale's head, once prized for clean-burning candles and replaced by jojoba oil after the whaling moratorium.
Spermacoce alata
Spermacoce alata Aubl. (syn. Borreria alata, S. latifolia), broadleaf buttonweed, a Rubiaceae herb native from Colombia to northern South America and W. Brazil, naturalized weed and medicinal plant in Asia, Africa, and Oceania.
Spermadhesin
Spermadhesins are 12–16 kDa CUB-domain secretory proteins of ungulate seminal plasma (pig, cattle, horse), major sperm-surface ligand-binding proteins with five porcine genes (AQN-1, AQN-3, AWN, PSP-I, PSP-II) involved in fertilization.
Spermatic cord
The spermatic cord (funiculus spermaticus) is either of a pair of tubular structures in males that suspends the testis in the scrotum and carries the ductus deferens, blood vessels, and nerves.
Spermatid
Spermatid (nematoblast, spermatoblast): haploid male germ cell (CL:0000018) formed from secondary spermatocytes by meiosis II; without dividing again it transforms via spermiogenesis, about 23 days in humans, into a spermatozoon.
Spermatocyte
Spermatocyte: male germ cell arising from spermatogonia; primary spermatocytes (diploid, largest germ cells) undergo a 24-day meiosis I in humans to form haploid secondary spermatocytes, which complete meiosis II in about 8 hours to yield four spermatids each.
Spermatocytic seminoma
Spermatocytic seminoma, now called spermatocytic tumour, is a rare testicular germ cell tumor of older men, unrelated to seminoma, lacking GCNIS, rarely metastasizing, cured by orchiectomy, with rare aggressive sarcomatous transformation.
Spermatogenesis
Spermatogenesis: production of haploid spermatozoa from spermatogonia via mitosis, meiosis, and spermiogenesis; 64–74 days in humans, FSH/testosterone-regulated, 150–275 million sperm daily.
Spermatogonium
Spermatogonium (Spermatogonia) is a diploid male germ cell at the earliest stage of spermatogenesis, residing on the basement membrane of the seminiferous tubules, where it maintains the stem cell pool.
Spermicide
Spermicide: chemical contraceptive, usually nonoxynol-9, in foams, gels, films, or suppositories; kills sperm, low effectiveness alone (18-28% annual failure), no STI protection, can irritate tissue.
Spermidine
Spermidine is a naturally occurring polyamine synthesized from putrescine in nearly all living cells, essential for protein synthesis, an inducer of autophagy, and a focus of longevity research.
Spermidine synthase
Spermidine synthase (SpdS, putrescine aminopropyltransferase, EC 2.5.1.16, human gene SRM) transfers an aminopropyl group from dcAdoMet to putrescine, making spermidine and MTA; structures, mechanism, and inhibitors known across species.
Spermine
Spermine is a naturally occurring polyamine required for eukaryotic growth, first observed as crystals in human semen by van Leeuwenhoek in 1678 and named for that source.