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Castration
Castration (orchiectomy/gonadectomy) is removal or destruction of the gonads, routinely performed on male livestock and pets to prevent breeding, reduce aggression, and improve meat quality; methods include surgery, Burdizzo, elastration, and GnRH immunocastration.
Casuarina
Casuarina is a genus of about 17 species of flowering trees and shrubs, native from tropical Asia to the western Pacific, known as she-oak or Australian pine.
Casuarina equisetifolia
Casuarina equisetifolia (she-oak, Australian pine, horsetail tree), a nitrogen-fixing Casuarinaceae tree native from India to the western Pacific; fast-growing coastal windbreak and fuelwood species, invasive and prohibited in Florida.
Casuarinaceae
Casuarinaceae R.Br. (she-oaks, beefwoods) is a Fagales family of four genera, Allocasuarina, Casuarina, Ceuthostoma, Gymnostoma, and about 90-97 species, native to Australia, Malesia, and the western Pacific, with jointed photosynthetic twigs, scale leaves, woody cones, and Frankia nitrogen-fixing root nodules.
Caswell A. Evans Jr.
Caswell A. Evans Jr. is an American dentist and dental public health specialist, best known as executive editor of the first Surgeon General's report on oral health in 2000.
Cat
Domestic cat (Felis catus), house cat, from Near Eastern wildcat Felis silvestris lybica; obligate-carnivore felid, nearly 1 billion worldwide, self-domesticated ~10,000 years ago, 70+ breeds, major predator of wildlife.
Cat anatomy
Cat anatomy: bodily structure of the domestic cat Felis catus, with 230–240 bones, vertebral formula C7 T13 L7 S3 Cd20–23, 30 teeth, vestigial clavicle, retractable claws, tapetum lucidum, and obligate-carnivore gut.
Cat behavior
Cat behavior covers the social, predatory, and developmental behavior of Felis catus: flexible feral grouping, a 2–7 week socialization window, solitary hunting, and strong individual variation in sociability toward humans.
Cat bite
A cat bite is a puncture wound from a cat's teeth, carrying a higher infection risk than bites from other domestic animals, infecting in 20 to 80% of cases.
Cat coat genetics
Cat coat genetics: genes controlling feline color and pattern, including ASIP agouti, TYRP1 brown, MLPH dilute, temperature-sensitive colorpoint, and the X-linked ARHGAP36 orange mutation behind ginger and calico cats.
Cat communication
Cat communication: how domestic cats (Felis catus) signal via vocalizations (meow, purr, chirp, hiss), scent marking, and body language; the meow is largely human-directed and shaped by domestication.
Cat intelligence
Cat intelligence: cognitive abilities of the domestic cat (Felis silvestris catus), covering object permanence, memory, concept learning, and human-directed social cognition; far less studied than dog cognition, with no settled cat-versus-dog verdict.
Cat meat
Cat meat (thịt mèo, "little tiger") is domestic cat flesh eaten in a few countries, mainly Vietnam, where over 1 million cats are trafficked yearly; banned in Taiwan, China, and the US.
Cat senses
Cat senses: the sensory systems of Felis catus, also called the domestic cat. Hearing reaches about 45 Hz to 65 kHz, smell is 14 times stronger than human, and the vomeronasal organ detects pheromones via the flehmen response.
CAT tailing
CAT tailing is a laboratory method for measuring poly(A) tail length on RNA, combining RNA circularization with tailing plus template switching to create a sequenceable tail.
Cat-eye syndrome
Cat-eye syndrome (Schmid-Fraccaro syndrome), a rare chromosomal disorder from partial tetrasomy or trisomy of 22q11, marked by iris coloboma, anal atresia, preauricular tags, and heart and kidney defects.
Cat-scratch disease
Cat-scratch disease (CSD) is a Bartonella henselae bacterial infection from cat scratches, especially kittens, causing fever and swollen lymph nodes; usually self-limited, treated with azithromycin when needed.
Catabolism
Catabolism, the energy-releasing half of metabolism, breaks down carbohydrates, fats, and proteins through four stages ending in the citric acid cycle and electron-transport chain, capturing energy as ATP.
Catabolite control protein A
Catabolite control protein A (CcpA), LacI/GalR-family transcription regulator of Gram-positive bacteria; with corepressor HPr-Ser46-P binds cre operators, mediating carbon catabolite repression, virulence, and antibiotic resistance links.
Catabolite repression
Carbon catabolite repression (CCR), also called catabolite repression, is a microbial regulatory mechanism that prioritizes preferred carbon sources like glucose, via PTS-cAMP-CRP in E. coli, CcpA-HPr in Firmicutes, and Hfq-Crc in Pseudomonas.
Catagonus
Catagonus is a genus of New World peccaries (Tayassuidae) named by Ameghino in 1904, best known for the endangered Chacoan peccary Catagonus wagneri, described as a fossil in 1930 and rediscovered alive in Paraguay in 1975.
Catahoula Leopard Dog
Catahoula Leopard Dog (Louisiana Catahoula Leopard Dog, Catahoula Cur), Louisiana's only native dog breed and state dog since 1979; a multi-purpose herding, hunting, and catch dog with varied merle coats and eye colors, 22-24 inches, 50-95 pounds.
Catalan Sheepdog
Catalan Sheepdog (Gos d'atura català), a medium Spanish herding dog from the Catalan Pyrenees, FCI breed 87, recognized 1929, with double hind dewclaws, long rough coat, fawn-sable-grey colors, 47-55 cm height.
Catalaphyllia
Catalaphyllia is a monotypic stony coral genus (Euphylliidae) whose sole species, C. jardinei, the elegance coral, is a turbid-water, soft-bottom Indo-West Pacific coral, CITES Appendix II, IUCN Least Concern (2024), with a published 651.3 Mb genome.
Catalase
Catalase (CAT, EC 1.11.1.6) is a heme tetrameric antioxidant enzyme in peroxisomes that decomposes hydrogen peroxide into water and oxygen; crystallized by Sumner and Dounce in 1937, used industrially in textile bleaching and studied as a therapy for oxidative stress diseases.
Catalase-peroxidase haem
Catalase-peroxidase haem (InterPro IPR000763) is the protein family of KatG enzymes, bifunctional heme b proteins with catalase and peroxidase activity, found in bacteria and fungi but not plants or animals.
Catalepsy (κατάληψις)
Catalepsy (κατάληψις) is a neuropsychiatric sign of prolonged involuntary posture-holding against gravity, a cardinal motor feature of catatonia in DSM-5, assessed by physical examination and distinct from cataplexy.
Catalpa
Catalpa (catalpa, Indian bean tree) is a genus of about eight Bignoniaceae tree species native to China, eastern North America, and the Greater Antilles, grown for showy white flowers and long bean-like pods; southern catalpa C. bignonioides and hardier northern catalpa C. speciosa are the common ornamentals.
Catalytic Domain
Catalytic domain: the region of an enzyme that interacts with its substrate to cause the enzymatic reaction (MeSH D020134). Carries the active site; conserved across evolution; examples include RuBisCO TIM barrel and polymerase palm domains.
Catalytic triad
A catalytic triad is a coordinated set of three amino acid residues in an enzyme's active site that together perform catalysis, typically a serine or cysteine nucleophile, a histidine base, and an aspartic acid.