Dictionary:

agar

  (ā'gär', ä'gär') also agar-agar (ā'gär-ā'gär', ä'gär-ä'-)

Also from Answers.com... Human Papilloma Virus HPV How to know if you have HPV.

1. A gelatinous material derived from certain marine algae. It is used as a base for bacterial culture media and as a stabilizer and thickener in many food products.
2. A culture medium containing this material.

[Short for Malay agar-agar.]

[AH-gahr; AY-gahr] Also called kanten and Japanese gelatin, this tasteless dried seaweed acts as a setting agent and is widely used in Asia. It is marketed in the form of blocks, powder or brittle strands and is available at Asian markets and natural food stores. Agar can be substituted for gelatin but has stronger setting properties (about 5 times greater) so less of it is required. Unlike gelatin, agar will set at room temperature.

A dried hydrophilic, colloidal substance extracted from various species of red algae. When suspended in a liquid medium and heated to 212°F (100°C), the agar dissolves. When it is allowed to cool to 110°F (43°C) the medium becomes a solid gel. It is used in culture media for bacteria and other microorganisms, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis. Because of its bulk it is also used in medicines to promote peristalsis and relieve constipation.

• birdseed a. — one containing Guizotia abyssinicia (Niger) seed and creatinine, used for growing Cryptococcus neoformans. Called also Niger agar.
• bismuth sulfite a. — a special preparation used for isolation of salmonellae from food.
• blood a. — a culture medium used for the growth of bacteria. Consists of agar and intact erythrocytes.
• brain heart infusion a. — used for cultivating the yeast phase of dimorphic fungi.
• brilliant green a. — used to cultivate salmonellae.
• chocolate a. — an enriched agar for the growth of Hemophilus, some Actinobacillus, and Taylorella spp. A molten agar and blood mixture is held at 122°F (50°C) prior to pouring plates. The additional nutrients supplied are hemin and NAD.
• a. diffusion test — see antimicrobial sensitivity test.
• eosin-methylene blue (EMB) a. — used for the identification of Eschericha coli.
• a. gel immunodiffusion test — see immunodiffusion tests.
• MacConkey a. — contains bile salts, lactose and neutral red indicator for isolation of enterobacteria.
• mannitol salt a. — selective for staphylococci.
• milk a. — contains skim milk and used to demonstrate casein digestion.
• Niger seed a. — see birdseed agar (above).
• nutrient a. — the basic growth medium for bacteria, composed of beef extract and peptone.
• potato dextrose a. — used in cultivating fungi; promotes sporulation and pigmentation.
• Sabouraud's dextrose a. — one used for isolation of fungi. See also dermatophyte test medium.
• a. sausage — see medium sausage.
• xylose lysine (XLD) a. — used to differentiate Enterbacteriaceae.