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Heterodon
Heterodon, the North American hog-nosed snakes (eastern, plains, Mexican, dusty, southern), is a dipsadid snake genus with upturned snouts, toad-heavy diet, death-feigning defense, mild rear-fang venom, and five species from Canada to Mexico.
Heterogeneous nuclear ribonucleoprotein
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a family of RNA-binding proteins that package newly made pre-mRNA in the nucleus and regulate splicing, export, stability, and translation.
Heterogeneous ribonucleoprotein particle
Heterogeneous ribonucleoprotein particles (hnRNPs): complexes of pre-mRNA (hnRNA) with about 20 canonical RNA-binding proteins (A1 to U) that package nascent transcripts, regulate splicing, export, and translation, and are implicated in ALS, cancer, and neurodevelopmental disorders.
Heterokaryon
Heterokaryon: a fungal cell or mycelium holding genetically different nuclei in one cytoplasm; coined by Burgeff (1912), controlled by het loci, central to the parasexual cycle and dikaryons.
Heterokaryon incompatibility
Heterokaryon incompatibility, also called vegetative incompatibility, is a fungal self/nonself recognition process in which hyphal fusion between strains differing at het or vic loci triggers programmed cell death, blocking stable heterokaryon formation and limiting mycovirus transfer.
Heterokaryon incompatibility Het-C
Het-C is a heterokaryon incompatibility locus in Neurospora crassa (alleles OR, PA, GR) and Podospora anserina, encoding polymorphic proteins whose unlike combinations trigger programmed cell death of fused hyphae.
Heterokaryon incompatibility protein 6
Heterokaryon incompatibility protein 6 (HET-6, het-6 gene, NCU03533) is a Neurospora crassa HET-domain protein that, with un-24, triggers programmed cell death between genetically unlike fungal strains via OR and PA haplotypes.
Heteromyidae
Heteromyidae, the kangaroo rats, kangaroo mice, and pocket mice, is a New World rodent family of about 59 species in 6 genera, defined by external fur-lined cheek pouches, seed caching, and desert-adapted nocturnal foraging.
Heteromys
Heteromys, forest spiny pocket mice, is a genus of heteromyid rodents (Desmarest, 1817) with 17 species ranging from Texas to Ecuador; the only heteromyid genus in South America, absorbing the former genus Liomys.
Heterophoria
Heterophoria (phoria, latent strabismus), ICD-10 H50.5, is a latent eye misalignment visible only when fusion is broken; about 80% of people have some degree, symptomatic only when vergence compensation fails.
Heteropoda venatoria
Heteropoda venatoria, the pantropical huntsman or giant crab spider (basionym Aranea venatoria), is a large Sparassidae spider from tropical Asia, introduced worldwide, with a 7–12 cm leg span, webless nocturnal cockroach hunting, and a painful but non-dangerous bite.
Heteropogon
Heteropogon (tanglehead) is a genus of about four to six tropical Andropogoneae grasses, type species H. contortus (black speargrass), with twisted hygroscopic awns, pungent calluses, pantropical savanna distribution, and non-monophyletic circumscription.
Heteropogon contortus
Heteropogon contortus (black speargrass, tanglehead, pili grass) is a tufted perennial Poaceae grass of the seasonally dry tropics, a major Queensland pasture grass whose barbed, twisted-awned seeds injure livestock and make it invasive in Florida.
Heterosis
Heterosis, also called hybrid vigor or outbreeding enhancement, is the superior performance of hybrid offspring over their parents on traits such as yield, growth rate, and fertility.
Heterospory
Heterospory is the production of two kinds of spores by the sporophytes of land plants: male microspores and larger female megaspores. It first evolved in the Devonian period.
Heterospory in ferns
Heterospory in ferns: production of microspores and megaspores with separate male and female gametophytes, found only in the water fern order Salviniales (Marsileaceae, Salviniaceae), evolved independently of lycophyte and seed plant heterospory.
Heterosynaptic plasticity
Heterosynaptic plasticity: lasting synaptic strength changes at synapses not active during induction, also called modulatory input-dependent plasticity. It counteracts Hebbian runaway dynamics, stabilizes synaptic weights, and supports long-term memory maintenance.
Heterotardigrada
Heterotardigrada (Marcus, 1927) is one of the two major tardigrade classes, sister to Eutardigrada, defined by a lateral cirrus, with orders Arthrotardigrada and Echiniscoidea; Arthrotardigrada may be paraphyletic.
Heterotis
Heterotis names two valid genera: Heterotis Benth. (1849), an African Melastomataceae plant genus with 5-7 species, and Heterotis Rüppell 1829, a monotypic arapaimid fish genus containing the African bonytongue Heterotis niloticus.
Heterotis niloticus
Heterotis niloticus, the African bonytongue or African arowana, is a large obligate air-breathing osteoglossiform fish native to Sahelo-Sudanese African river basins, introduced elsewhere, IUCN Least Concern, and used in fisheries and aquaculture.
Heterotopic sebaceous glands
Heterotopic sebaceous glands, also called ectopic sebaceous glands or Fordyce spots, are hair-follicle-free oil glands at mucosal sites such as the lips, buccal mucosa, and genitals; benign, present in about 80% of adults, ICD-11 ED91.0.
Heterotopic transplantation
Heterotopic transplantation is a surgical approach that implants an organ graft at a non-anatomical site while leaving the native organ in place, as in the piggyback heart transplant.
Heterotroph
Heterotroph: organism obtaining carbon and energy from organic compounds made by autotrophs; includes all animals, fungi, most bacteria; spans consumers, detritivores, chemoheterotrophs, and photoheterotrophs.
Heterozygote
Heterozygote (heterozygous): an individual carrying two different alleles at a gene locus, one from each parent. Covers dominance, carriers, heterozygote advantage such as sickle-cell malaria resistance, and molecular heterosis.
Hevea
Hevea is a genus of ten Euphorbiaceae tree species native to South Tropical America; Hevea brasiliensis, the rubber tree, supplies all commercial natural rubber, used mainly in tires, with guayule and dandelion as alternatives.
Hevea brasiliensis
Hevea brasiliensis, the Pará rubber tree, is an Amazonian Euphorbiaceae tree whose phloem latex is the sole commercial source of natural rubber, grown mainly in Southeast Asian plantations and limited in South America by South American leaf blight.
Hexachlorophene
Hexachlorophene, sold as Phisohex, is a chlorinated bisphenol compound that was widely used for decades as a topical antiseptic in soaps and surgical scrubs before neurotoxicity concerns led to severe restrictions on its use.
Hexaconazole
Hexaconazole, a systemic triazole (conazole) fungicide introduced by Zeneca in 1986, inhibits 14-alpha-sterol demethylase in ergosterol synthesis; used on rice, fruit, vegetables, and wood, with enantioselective activity and toxicity.
Hexacorallia
Hexacorallia (Zoantharia) is a cnidarian subclass of Anthozoa with six-fold polyp symmetry, containing six orders: sea anemones, stony corals, black corals, tube anemones, corallimorpharians, and zoanthids.
Hexactinellid
Hexactinellid (glass sponge, class Hexactinellida): marine sponge with six-rayed siliceous spicules, syncytial tissue, no mesohyl; deep-sea, 200 to over 6,000 m; oldest sponge group.