Columbia Encyclopedia

Search results

403 results found

ehrlichiosis

(Encyclopedia)ehrlichiosis ârlĭkēōˈsĭs [key], any of several diseases caused by rickettsia of the genera Ehrlichia and Anaplasma. Ehrlichiosis is transmitted by ticks. Both human forms tend to develop about n...

Clostridium

(Encyclopedia)Clostridium, genus of gram-positive bacteria (see Gram's stain), several species of which cause significant, potentially deadly diseases in humans as a result of the toxins that each produces. Clostri...

neurotransmitter

(Encyclopedia)neurotransmitter, chemical that transmits information across the junction (synapse) that separates one nerve cell (neuron) from another nerve cell or a muscle. Neurotransmitters are stored in the nerv...

Nematoda

(Encyclopedia)Nematoda nĕmˌətōdˈə [key], phylum consisting of about 12,000 known species, and many more predicted species, of worms (commonly known as roundworms or threadworms). Nematodes live in the soil an...

sunburn

(Encyclopedia)sunburn, inflammation of the skin caused by actinic rays from the sun or artificial sources. Moderate exposure to ultraviolet radiation is followed by a red blush, but severe exposure may result in bl...

measles

(Encyclopedia)measles or rubeola ro͞obēˈələ [key], highly contagious disease typically contracted during childhood, caused by a filterable virus and spread by droplet spray from the nose, mouth, and throat of ...

Hippocrates

(Encyclopedia)Hippocrates hĭpŏkˈrətēz [key], c.460–c.370 b.c., Greek physician, recognized as the father of medicine. He is believed to have been born on the island of Cos, to have studied under his father, ...

alkaloid

(Encyclopedia)alkaloid, any of a class of organic compounds composed of carbon, hydrogen, nitrogen, and usually oxygen that are often derived from plants. Although the name means alkalilike, some alkaloids do not e...

coronavirus

(Encyclopedia)coronavirus, any of a group (family Coronaviridae, subfamily Orthocoronavirinae) of enveloped single-stranded RNA viruses that have a crownlike or sunlike appearance under an electron microscope due t...

Pauling, Linus Carl

(Encyclopedia)Pauling, Linus Carl pôˈlĭng [key], 1901–94, American chemist, b. Portland, Oreg. He was one of the few recipients of two Nobel Prizes, winning the chemistry award in 1954 and the peace prize in 1...